Patent Publication Number: US-2022225998-A1

Title: Treating Heart Tissue

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. patent application Ser. No. 13/925,107 filed on Jun. 24, 2013, which is a continuation of U.S. patent application Ser. No. 13/549,585 filed on Jul. 16, 2012, which is a division of U.S. patent application Ser. No. 12/786,785 filed on May 25, 2010 and entitled “Treating Heart Tissue.” The entire contents of these previous applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This document relates to systems and methods that are configured to treat heart tissue, for example, to redistribute blood to damaged or ischemic heart muscle tissue. 
     BACKGROUND 
     The heart muscle receives arterial blood via coronary arteries so that the blood passes through and nourishes the heart muscle tissue. In some cases, a blockage in a coronary artery can result in a loss of blood flow through a portion of the heart muscle tissue, thereby creating an area of damaged or ischemic heart muscle tissue. After the blockage is removed or otherwise opened to resume blood flow, the ischemic portion of the heart muscle tissue (such as the reperfused microcirculation) may be damaged to point that normal blood flow does not return through the ischemic portion of the muscle tissue. 
     Some conventional systems attempt to repair or treat the ischemic heart muscle tissue by supplying the ischemic tissue with blood through retrograde perfusion. For example, the coronary sinus may be temporarily occluded so that the blood therein counterflows back from the coronary sinus through the coronary venous system and toward the ischemic muscle tissue that previously did not receive blood from the arterial side. The occlusion of the coronary sinus causes a pressure increase and, as a result, a redistribution of venous blood via the respective vein(s) into the capillaries of the border-zone ischemic muscle tissue so as to improve the supply of nutrients to that ischemic area. When the occlusion is ceased so that blood exits normally through the coronary sinus, the venous blood is flushed out while the metabolic waste products from the damaged tissue are carried off at the same time. The combination of venous pressure build-up with redistribution of flow and wash-out is believed to improve arterial blood demand and reduce ischemic tissue infarct size. Typically, the instrument for occluding the coronary sinus is employed during or after treatment of the blockage in the coronary artery. Thus, a coronary intervention tool (e.g., stent, angioplasty balloon, or the like) would be used to treat the blockage on the coronary arterial system before making any attempt to temporarily occlude the coronary sinus of the coronary venous system. 
     SUMMARY 
     Some embodiments of a system or method for treating heart tissue enable a surgeon or other user to treat ischemic or otherwise damaged heart muscle tissue (e.g., caused by a coronary arterial blockage or other ailment) by redistributing venous blood flow to the damaged heart muscle tissue. In particular, the system and methods may be configured to pre-treat the heart tissue before any blockage in a coronary artery is repaired or removed. In these circumstances, the ischemic or otherwise damaged heart muscle tissue can receive a redistribution of blood flow from the coronary venous system (e.g., due to an instrument that temporarily occludes the coronary sinus) prior to the restoration of normal blood flow from the coronary arterial system. Such pre-treatment of the heart muscle tissue can lead to improved muscle tissue recovery after the coronary arterial blockage is treated and arterial blood flow returns to the previously blood-deprived portion of the heart muscle tissue. 
     In addition or in the alternative, some embodiments of the system for treating heart tissue can include a coronary sinus occlusion catheter having an inflatable balloon device and a control system to control the inflation and deflation of the inflatable balloon device. Preferably, the coronary sinus occlusion catheter can be activated to perform a pressure-controlled intermittent coronary sinus occlusion (PICSO) procedure for at least a portion of the time in which the catheter  120  is positioned in the coronary sinus of the heart. The control system can be equipped with a graphical user interface that provides a surgeon or other user with time-sensitive, relevant data indicative of the progress of PICSO procedure and the condition of the heart. As such, the user can readily monitor the patient&#39;s condition and the effects of the PICSO treatment by viewing the individual graphical user interface while contemporaneously handling the coronary sinus occlusion catheter other heart treatment instruments. In particular circumstances, the control system can be configured to activate the inflatable balloon device as part of a predetermined pattern of occlusion periods and release periods that is independent of the coronary sinus pressure or as part of a pressure-dependent pattern that is at least partially defined by the coronary sinus pressure readings during the procedure. 
     In some embodiments, a method of treating heart tissue may include detecting a blockage in a coronary artery of the heart. The method may also include prior to intervening on the blockage in the coronary artery, advancing distal tip portion of a coronary sinus occlusion catheter through a guide sheath in a right atrium and into the coronary sinus. The coronary sinus occlusion catheter may include an inflatable balloon device configured to occlude the coronary sinus when inflated. The method may further include intermittently occluding the coronary sinus using the inflatable balloon device of the coronary sinus occlusion catheter to redistribute venous blood flow into heart muscle tissue affected by the blockage. The method may also include after intermittently occluding the coronary sinus, delivering a coronary intervention tool via a body artery and to the blockage in the coronary artery of the heart to perform a coronary intervention procedure. 
     In particular embodiments, a method of treating heart tissue may include delivering a distal end of a guide member though a venous system and into a right atrium. The method may also include advancing a distal tip portion of a first coronary sinus occlusion catheter slidably along the guide member in the right atrium and into a coronary sinus. The first coronary sinus occlusion catheter may include an inflatable balloon device configured to occlude the coronary sinus when inflated. The method may further include intermittently occluding the coronary sinus using the inflatable balloon device of the first coronary sinus occlusion catheter to redistribute venous blood into heart muscle tissue affected by the blockage. The method may also include, after intermittently occluding the coronary sinus, withdrawing the first coronary sinus occlusion catheter from a proximal end of the guide member while the distal end of the guide member remains in the right atrium. The method may further include monitoring bodily characteristics for a period of time after the first coronary sinus occlusion catheter is withdrawn. The method may also include delivering a distal tip portion of a second coronary sinus occlusion catheter via the guide member remaining in the right atrium and into the coronary sinus. The second coronary sinus occlusion catheter may be different from first coronary sinus occlusion catheter. 
     In some embodiments, a system for treating heart muscle tissue may include a coronary sinus occlusion catheter including a distal tip portion, a proximal hub portion, a pressure sensor lumen, and a balloon fluid lumen. The distal tip portion of the coronary sinus occlusion catheter may include an inflatable balloon device configured to occlude a coronary sinus when inflated with fluid via the balloon fluid lumen. The system may also include a control system to control the inflation and deflation of the inflatable balloon device for pressure-controlled intermittent coronary sinus occlusion. The control system may include a display device, a pressure signal input that receives a pressure signal indicative of coronary sinus pressure, an electrocardiogram (ECG) signal input, and a control circuit that activates a pneumatic subsystem to inflate or deflate the inflatable balloon device of the coronary sinus occlusion catheter for a selected period of time based at least in part on the pressure signal indicative of the coronary sinus pressure. The control system, during an initial period of operation, may activate the inflatable balloon device of the coronary sinus occlusion catheter to intermittently occlude the coronary sinus in a predetermined pattern of occlusion periods and release periods that is independent of the pressure signal indicative of the coronary sinus pressure. Also, the control system, during a second period of operation, may activate the inflatable balloon device of the coronary occlusion catheter to intermittently occlude the coronary sinus in a pattern that is dependent in part on the pressure signal indicative of the coronary sinus pressure. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a portion of a system for treating heart tissue, in accordance with some embodiments. 
         FIG. 2  is a perspective view of another portion of the system of  FIG. 1 . 
         FIG. 3  is a diagram of a control system illustrated in the system of  FIG. 2 . 
         FIG. 4  is a cross-sectional view of a catheter device and a guide member of the system of  FIG. 1 . 
         FIG. 5  is a side view of a portion of the catheter device of  FIG. 4 . 
         FIG. 6  is a cross-sectional view of a shaft portion the catheter device of  FIG. 4 . 
         FIG. 7  is a cross-sectional view of a tip portion the catheter device of  FIG. 4 . 
         FIG. 8  is a perspective view of the catheter device and the guide member of the system of  FIG. 1 , with the tip portion of the catheter device being arranged in a coronary sinus of a heart. 
         FIG. 9  is a perspective view of the catheter device and the guide member of  FIG. 8 , with a coronary intervention tool arranged in a coronary artery. 
         FIG. 10  is a perspective view of the guide member of  FIG. 8 , with the catheter device being withdrawn. 
         FIG. 11  is a flow chart of a process for of treating heart tissue, in accordance with some implementations. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-2 , some embodiments of a system  100  for treating heart tissue can include a coronary sinus occlusion catheter  120  and a control system  140  ( FIG. 2 ). The control system  140  can be configured to control the operation of the catheter  120  for providing pressure-controlled intermittent coronary sinus occlusion (PICSO) and to receive heart sensor data for display. The coronary sinus occlusion catheter  120  includes a distal tip portion  121  (leading to a distal end depicted in  FIG. 1 ) and a proximal portion  131 , which includes a proximal hub  132  that is coupled to the control system  140  via a number of fluid or sensor lines  133 ,  134 , and  135 . Accordingly, the control system  140  may be employed to operate one or more components at the distal tip portion  121  of the coronary sinus occlusion catheter  120  while also receiving one or more sensor signals that provide data indicative of heart characteristics (e.g., coronary sinus pressure, electrocardiogram (ECG) information, and the like). 
     Briefly, in use, the distal tip portion  121  of the coronary sinus occlusion catheter  120  can be arranged in a coronary sinus  20  of a heart  10  and thereafter activated to intermittently occlude the blood flow exiting from the coronary sinus  20  and into the right atrium  11 . During such an occlusion of the coronary sinus  20 , the venous blood flow that is normally exiting from the coronary sinus  20  may be redistributed into a portion of heart muscle tissue  30  that has been damaged due to blood deprivation or loss of functional myocardium. For example, the portion of heart muscle tissue  30  can suffer from a lack of blood flow due to a blockage  35  in a coronary artery  40 . As a result, the arterial blood flow to the affected heart muscle tissue  30  via a local artery  41  can be substantially reduced such that the heart muscle tissue  30  becomes ischemic or otherwise damaged. Further, because the arterial blood flow is reduced, the venous blood flow exiting from the local vein  21  is likewise reduced. Other branch veins  22  located at different regions along the heart  10  may continue to receive blood flow, thereby creating a supply of venous blood flow exiting through the coronary sinus  20 . In some embodiments, the coronary sinus occlusion catheter  120  can be delivered into the coronary sinus  20  and thereafter activated so as to intermittently occlude the coronary sinus  20  prior to treating the blockage  35  on the arterial side. Such an occlusion can cause the venous blood flow to be redistributed to the local vein  21  and then into the portion of heart muscle tissue  30  can suffer from a lack of blood flow due to a blockage  35  in a coronary artery  40 . As such, the ischemic or otherwise damaged heart muscle tissue  30  can be “pre-treated” with the redistributed venous blood flow in that the heart muscle tissue  30  receives an improved the supply of nutrients before the blockage  35  is repaired or removed to restore normal coronary arterial blood flow. 
     Furthermore, in use, the control system  140  ( FIG. 2 ) is configured to provide automated control of an occlusion component (e.g., an inflatable balloon  122  or the like) of the coronary sinus occlusion catheter  120 . As described in more detail below, the control system  140  includes a computer processor that executes computer-readable instructions stored on a computer memory device so as to activate or deactivate the occlusion in the coronary sinus  20  in accordance with particular patterns. For instance, the control system  140  can be configured to activate the occlusion component of the catheter  120  in the coronary sinus  20  as part of a predetermined pattern of occlusion periods and release periods that is independent of the coronary sinus pressure, or as part of a pressure-dependent pattern that is at least partially defined by the coronary sinus pressure readings during the procedure. In addition, the control system  120  is equipped with a display device  142  having a graphical user interface that provides a surgeon or other user with time-sensitive, relevant data indicative of the progress of a coronary sinus occlusion procedure and the condition of the heart  10 . As such, the user can readily monitor the patient&#39;s condition and the effects of intermittently occluding the coronary sinus  20  by viewing the graphical user interface while contemporaneously handling the coronary sinus occlusion catheter  120  other heart treatment instruments (e.g., angioplasty catheters, stent delivery instruments, or the like). It is believed that a rapid change in coronary flow can be detected by observing the pressure in the occluded coronary sinus, thus indicating any detrimental change of nutritive flow. Likewise, an improvement of coronary flow can be detected using trend data (i.e., coronary sinus pressure measurements over a period of time). An abrupt increment of coronary flow (e.g., when a stent is inserted to reopen a coronary artery in acute coronary syndromes) can also be detected by an increment of pressure in the occluded coronary sinus. Furthermore, the pressure increase in the coronary sinus may also indicate a level of resistance in the ischemic tissue/reperfused microcirculation, thereby providing the cardiologist with an indication for the integrity of these vessels and the success of the percutaneous coronary interventional procedure. 
     It should be understood from the description herein that, in some embodiments, the control system  140  and the coronary sinus occlusion catheter  120  can be used as part of a system for “pre-treating” the heart muscle tissue before the blockage  35  is repaired or removed to restore normal coronary arterial blood flow (as previously described). In some alternative embodiments, the control system  140  and the coronary sinus occlusion catheter  120  can be used as part of a system that intermittently occludes the coronary sinus  20  after the blockage  35  is repaired or removed to restore normal coronary arterial blood flow. 
     Referring in more detail to  FIG. 1 , the coronary sinus occlusion catheter  120  can be delivered via the venous system to the coronary sinus  20  prior to repairing or treating the blockage  35  the coronary artery  40 . In such circumstances, the portion of heart muscle tissue  30  that is damaged due to lack of arterial blood flow (as a result of the blockage) can be pre-treated with a supply of venous blood before the normal arterial blood flow is restored (as a result of repairing or removing the blockage  35 ). For example, as shown in  FIG. 1 , the distal tip portion  121  is delivered into the coronary sinus  20  for purposes of intermittently occluding the coronary sinus  20  before another catheter or instrument is advanced to the blockage  35  in the coronary artery  40 . 
     The system  100  may include a guide member  110  that is advanced through the venous system of the patient and into the right atrium  11 . The guide member  110  in this embodiment comprises a guide sheath having a lumen extending between a distal end  111  ( FIG. 1 ) and a proximal end  112  ( FIG. 4 ). In alternative embodiments, the guide member  110  can include a guide wire having an exterior surface extending between the distal end and the proximal end. Optionally, the guide member  110  includes a steerable mechanism to control the orientation of the distal end so as to steer the distal end  111  through the venous system and into the right atrium  11 . Also, the guide member  110  can include one or more marker bands along the distal end  111  so that the position of the distal end can be monitored during advancement using an imaging device. 
     After the guide member  110  is advanced into the right atrium  11 , the distal end  111  may be temporarily positioned in the coronary sinus  20 . From there, the distal tip portion  121  of the coronary sinus occlusion catheter  120  can be slidably advanced along the guide member  110  for positioning inside the coronary sinus  20 . In the embodiments in which the guide member  110  comprises a guide sheath, the distal tip portion  121  of the coronary sinus occlusion catheter  120  can slidably engage with an interior surface of the lumen during advancement toward the coronary sinus  20 . In the alternative embodiments in which the guide member  110  comprises a guide wire structure, the distal tip portion  121  of the coronary sinus occlusion catheter  120  can slidably advance over the exterior surface of the guide wire (e.g., a lumen of the catheter  120  passes over the guide wire) during advancement toward the coronary sinus  20 . After the coronary sinus occlusion catheter  120  reaches the coronary sinus  20 , the distal end  111  of the guide member  110  can be withdrawn from the coronary sinus  20  and remain in the right atrium  11  during use of the coronary sinus occlusion catheter  120 . 
     Still referring to  FIG. 1 , the distal tip portion  121  of the coronary sinus occlusion catheter  120  that is positioned in the coronary sinus  20  includes an occlusion component  122 , which in this embodiment is in the form of an inflatable balloon device. The occlusion component  122  can be activated so as to occlude the coronary sinus  20  and thereby cause redistribution of the venous blood into the heart muscle tissue  30  that is damaged due to a lack of arterial blood flow. As described in more detail below, the inflatable balloon device  122  can be in fluid communication with an internal lumen of the coronary sinus occlusion catheter  120 , which is in turn in communication with a pneumatic subsystem of the control system  140  ( FIG. 2 ). As such, the control system  140  can be employed to expand or deflate the balloon device  122  in the coronary sinus. 
     The distal tip portion  121  also includes a one or more distal ports  129  that are positioned distally forward of the inflatable balloon device. In the depicted embodiments, the distal ports  129  face is a generally radially outward direction and are substantially uniformly spaced apart from one another along the circumference of the distal tip. As described in more detail below, the distal ports  129  may all be in fluid communication with a single pressure sensor lumen extending through the coronary sinus occlusion catheter  120 . Accordingly, the coronary sinus pressure can be monitored via a pressure sensor device that is in fluid communication with the distal ports  129 . 
     Further details of particular embodiments of the coronary sinus occlusion catheter  120  are described in more detail below in connection with  FIGS. 4-7 . 
     Referring now to  FIG. 2 , the proximal portion  131  of the coronary sinus occlusion catheter  120  and the control system  140  are positioned external to the patient while the distal tip portion  121  is advanced into the coronary sinus  20 . The proximal portion  131  includes the proximal hub  132  that is coupled to the control system  140  via a set of fluid or sensor lines  133 ,  134 , and  135 . As such, the control system  140  can activate or deactivate the occlusion component  122  at the distal tip portion  121  of the coronary sinus occlusion catheter  120  while also receiving one or more sensor signals that provide data indicative of heart characteristics (e.g., coronary sinus pressure, electrocardiogram (ECG) information, and the like). 
     The proximal hub  132  of the coronary sinus occlusion catheter  120  serves to connect the plurality of fluid or sensor lines  133 ,  134 , and  135  with the portion of the coronary sinus occlusion catheter  120  that extends into the patient&#39;s venous system. For example, the first line  133  extending between the control system  140  and the proximal hub  132  comprises a fluid line through which pressurized fluid (e.g., helium, another gas, or a stable liquid) can be delivered to activate the occlusion component (e.g., to inflate the inflatable balloon device  122 ). The fluid line  133  is connected to a corresponding port  143  of the control system  140  (e.g., the drive lumen port in this embodiment) so that the line  133  is in fluid communication with the pneumatic subsystem  153  housed in the control system  140  (as shown in  FIG. 3 ). The proximal hub  132  joins the first line  133  with a balloon control lumen  123  ( FIG. 6 ) extending through the coronary sinus occlusion catheter  120  and to the inflatable balloon device  122 . 
     In another example, the second line  134  extending between the control system  140  and the proximal hub  132  comprises a balloon sensor line that is in fluid communication with the interior of the inflatable balloon device  122  so as to measure the fluid pressure within the balloon device  122 . The proximal hub  132  joins the second line  134  with a balloon pressure lumen  124  ( FIG. 6 ) extending through the coronary sinus occlusion catheter  120  and to the inflatable balloon device  122 . The pressure of the balloon device  122  may be monitored by an internal control circuit  155  ( FIG. 3 ) of the control system  140  as part of a safety feature that is employed to protect the coronary sinus  20  from an overly pressurized balloon device. The balloon sensor line  134  is connected to a corresponding port  144  of the control system  140  so that a pressure sensor arranged within the control system  140  can detect the fluid pressure in the balloon device  122 . Alternatively, the pressure sensor may be arranged in the distal tip portion  121  or the in the proximal hub  132  such that only a sensor wire connects to the corresponding port  144  of the control system  140 . 
     The proximal hub also connects with a third line  135  extending from the control system  140 . The third line  135  comprises a coronary sinus pressure line that is used to measure the fluid pressure in the coronary sinus both when the balloon device  122  is inflated and when it is deflated. The proximal hub  132  joins the third line  135  with a coronary sinus pressure lumen  125  ( FIGS. 5-6 ) extending through the coronary sinus occlusion catheter  120  and to the distal ports  129  that are forward of the balloon device  122 . As such, the coronary sinus pressure lumen  125  and at least a portion of the third line  135  may operate as fluid-filled path (e.g., saline or another biocompatible liquid) that transfers the blood pressure in the coronary sinus  20  to pressure sensor device  136  along a proximal portion of the third line  135 . The pressure sensor device  136  samples the pressure measurements (which are indicative of the coronary sinus pressure) and outputs an sensor signal indicative of the coronary sinus pressure to the corresponding port  145  of the controller system  140  for input to the internal control circuit  155  ( FIG. 3 ). As described in more detail below, the coronary sinus pressure data are displayed by the graphical user interface  142  in a graph form  156  (refer to  FIG. 3 ) so that a surgeon or other user can readily monitor the trend of the coronary sinus pressure while the coronary sinus  20  is in an occluded condition and in an non-occluded condition. Optionally, the graphical user interface  142  of the control system  140  can also output a numeric pressure measurement  157  (refer to  FIG. 3 ) on the screen so that the surgeon can readily view a maximum coronary sinus pressure, a minimum coronary sinus pressure, or both. In alternative embodiments, the pressure sensor device  136  can be integrated into the housing  141  of the control system  140  so that the third line  135  is a fluid-filled path leading up to the corresponding port  145 , where the internal pressure sensor device (much like the device  136 ) samples the pressure measurements and outputs a signal indicative of the coronary sinus pressure. 
     Still referring to  FIG. 2 , the system  100  may include one or more ECG sensors  149  to output ECG signals to the control system  140 . In this embodiment, the system  100  includes a pair of ECG sensor pads  149  that are adhered to the patient&#39;s skin proximate to the heart  10 . The ECG sensors  149  are connected to the control system  140  via a cable that mates with a corresponding port  149  along the housing of the control system  140 . As described in more detail below, the ECG data are displayed by the graphical user interface  142  in a graph form  158  (refer to  FIG. 3 ) so that a surgeon or other user can readily monitor the patient&#39;s heart rate and other characteristics while the coronary sinus is in an occluded condition and in an non-occluded condition. Optionally, the graphical user interface  142  of the control system  140  can also output numeric heart rate data  159  (refer to  FIG. 3 ) (based on the ECG sensor data on the screen so that the surgeon can readily view the heart rate (e.g., in a unit of beats per minutes). The ECG sensor signals that are received by the control system  140  are also employed by the internal control circuit  155  ( FIG. 3 ) so as to properly time the start of the occlusion period (e.g., the start time at which the balloon device  122  is inflated) and the start of the non-occlusion period (e.g., the start time at which the balloon device  122  is deflated). 
     As shown in  FIG. 2 , the coronary sinus occlusion catheter  120  is delivered to the heart  10  via a venous system using any one of a number of venous access points. Such access points may be referred to as PICSO access points in some embodiments in which the coronary sinus occlusion catheter  120  is controlled to perform a PICSO procedure for at least a portion of the time in which the catheter  120  is positioned in the coronary sinus  20 . For example, the guide member  110  and the distal tip portion  121  can be inserted into the venous system into an access point at a brachial vein, an access point at a subclavian vein, or at an access point at a jugular vein. From any of these access points, the guide member  110  can be advanced through the superior vena cava and into the right atrium  11 . Preferably, the guide member  110  is steered into an ostial portion of the coronary sinus  20 , and then the distal tip portion  121  of the catheter  120  is slidably advanced along the guide member  110  and into the coronary sinus  20  before the guide member  110  is backed out to remain in the right atrium  11 . In another example, the guide member  110  and the distal tip portion  121  can be inserted into the venous system into an access point at a femoral vein. In this example, the guide member  110  can be advanced through the inferior vena cava and into the right atrium  11 . As previously described, the distal tip portion  121  of the catheter  120  is slidably advanced along the guide member  110  and into the coronary sinus  20  before the guide member  110  is backed out to remain in the right atrium  11 . 
     In some embodiments, the coronary sinus occlusion catheter  120  is delivered to the coronary sinus  20  so as to pre-treat the heart tissue with redistributed venous blood flow before the blockage  35  in the coronary artery  40  is repaired or removed. In these circumstances, the damaged portion of heart muscle tissue  30  can receive a redistribution of blood flow from the coronary venous system (e.g., due to balloon device  122  that intermittently occludes the coronary sinus) prior to the restoration of normal blood flow from the coronary arterial system. Such pre-treatment of the heart muscle tissue can lead to improved muscle tissue recovery after the coronary arterial blockage is treated and arterial blood flow returns to the previously blood-deprived portion of the heart muscle tissue. In these embodiments, the coronary sinus occlusion catheter  120  can be delivered into the venous system (via one of the previously described PICSO access points illustrated in  FIG. 2 ) before a different coronary intervention tool is delivered into the arterial system for purposes of repairing or removing the blockage  35 . For example, the blockage  35  may be repaired or removed using a percutaneous coronary intervention (PCI) instrument such as an angioplasty balloon catheter, a stent delivery instrument, or the like. The PCI instrument may access the arterial system via any one of a number of PCI access points. In some implementations, the PCI instrument can be inserted into the arterial system into an access point at a femoral artery, an access point at a radial artery, or an access point at a subclavian artery. Thus, as previously described, some embodiments of the system  100  may employ a PICSO access point into the venous system prior to a PCI access point is employed to insert a PCI instrument into the arterial system. 
     Referring now to  FIG. 3 , some embodiments of the control system  140  include the internal control circuit subsystem  155  that communicates with the pneumatics subsystem  153 . The control circuit subsystem  155  can include one or more processors  152  that are configured to execute various software modules stored on at least one memory device  154 . The processors  152  may include, for example, microprocessors that are arranged on a motherboard so as to execute the control instructions of the control system  140 . The memory device  154  may include, for example, a computer hard drive device having one or more discs, a RAM memory device, that stored the various software modules. 
     In some embodiments, the memory device of the control circuit subsystem  155  stores a graphical user interface software module including computer-readable instructions for controlling the graphical user interface  142 . These graphical user interface control instructions may be configured to cause the interface  142  (which includes a touch screen display device in this embodiment) to display: the pressure data graph  156  indicative of the coronary sinus pressure, the coronary sinus pressure numerical data  157 , the ECG data graph  158 , and the heart rate numerical data  159  (previously described in connection with  FIG. 2 ). Optionally, the graphical user interface can be configured to display more than two the two graphs  157  and  158  on the screen. For example, in some embodiments, the graphical user interface can be configured to contemporaneously display three or four different graphs, such as the coronary sinus pressure numerical data  157 , the ECG data graph  158 , a third graph that depicts the arterial pressure as a function of time, and a fourth graph that illustrates another data output (e.g., the volume of blood flow). 
     Further, the graphical user interface control instructions stored in the control circuit subsystem  155  may be configured to cause the interface  142  to display numeric data of the time periods during which the coronary sinus is in an occluded state and in a non-occluded state. For example, the graphical user interface  142  can provide the occluded time numeric data  161  in units of seconds (e.g.,  7  seconds as shown in  FIG. 3 ). Also, the graphical user interface  142  can provide the non-occluded time numeric data  162  in units of seconds (e.g.,  11  seconds as shown in  FIG. 3 ). The calculation of the time periods during which the coronary sinus is in an occluded state and in a non-occluded state may be completed by the balloon inflate and deflate software module stored on the memory device  154 , as described in more detail below. This software module can be configured to determine a time derivative of the coronary sinus pressure curve over time during PICSO, which can be employed as a parameter in determining the balloon inflate and deflate times. The graphical user interface control instructions stored in the control circuit subsystem  155  may be configured to cause the interface  142  to display a number of touch screen buttons  163 ,  164 ,  165 , and  166  that enable the surgeon or other user to select different menu options or to input patient information or other data. In addition, the graphical user interface control instructions stored in the control circuit subsystem  155  may be configured to cause the interface  142  to display a number of one or more alerts  167 , which can be in the form of error messages or codes. The determination of which alert condition, if any, should be display is completed by the patient safety monitoring software module stored on the memory device  154 , as described in more detail below. 
     Still referring to  FIG. 3 , the balloon inflate and deflate software module stored on the memory device  154  can include computer-readable instructions that, when executed by one of the processors  152  (such as an embedded microprocessor), causes the pneumatic subsystem  153  to activate or deactivate the balloon device  122  at selected times. In some embodiments, the balloon inflate and deflate software module stored on the memory device  154  can implement a customized algorithm that calculates and updates the time periods during which the coronary sinus is in an occluded state and in a non-occluded state based upon the coronary sinus pressure measurements. In such circumstances, the coronary sinus  20  is not occluded and non-occluded according to a predetermined pattern of inflated times and deflated times that are independent of the patient, but instead the coronary sinus pressure measurements at least partially dictate the time periods during which the coronary sinus is in an occluded state and in a non-occluded state. In alternative modes, the balloon inflate and deflate software module stored on the memory device  154  may cause the coronary sinus  20  to be occluded and non-occluded according to a predetermined pattern of inflated times and deflated times that are independent of the patient and the coronary sinus pressure measurements. For example, as described in more detail below, the control circuit subsystem  154  may execute the balloon inflate and deflate software module and communicate with the pneumatic subsystem  153  to inflate and deflate the balloon device  122  according to the predetermined pattern of inflated times and deflated times during an initial phase when the catheter  120  is first delivered into the coronary sinus  20  and initially activated. After this initial phase during which the coronary sinus pressure measurements are sampled and displayed, the control circuit subsystem  154  may execute the balloon inflate and deflate software module and communicate with the pneumatic subsystem  153  so as to inflate and deflate the balloon device  122  according to the customized algorithm that is dependent upon the coronary sinus pressure measurements in the patient (e.g., a PICSO procedure in which the intermittent occlusion of the coronary sinus is pressure-controlled). 
     After this second phase during which the pneumatic subsystem  153  inflates and deflate the balloon device  122  according to the customized algorithm that is dependent upon the coronary sinus pressure measurements in the patient, the control circuit subsystem  154  may execute the balloon inflate and deflate software module during a third phase that again uses the predetermined pattern of inflated times and deflated times that are independent of the patient and the coronary pressure measurements. Because this predetermined pattern of occlusion periods and release periods from the first (initial) phase is repeated during the third phase, the coronary sinus pressure readings from these two different phases can be compared. For example, the coronary sinus pressure measurements during this third phase (having the predetermined pattern of occlusion and non-occlusion) is used to compare with the previous coronary sinus pressure measurements during the earlier first phase (having the predetermined pattern of occlusion and non-occlusion). The comparison can be displayed by the control system  140  so that the surgeon or other user can determine if the intermittent coronary sinus occlusion procedure has reached its clinical efficacy end-point or if further delivery of the coronary sinus occlusion treatment is required. In some cases, the cardiologist can observe the trend data (e.g., the coronary sinus pressure curve that increased toward a plateau level) to determine if clinical stability is reached (e.g., when the trend flattens). 
     The patient safety monitoring software module stored on the memory device  154  can include computer-readable instructions that, when executed by one of the processors  152 , causes the control circuit subsystem  155  to detect if any of the system sensors (e.g., the pressure sensors) output a measurement that is outside of a selected safety range. For example, if the coronary sinus pressure signal input to the control system  140  indicates a coronary sinus pressure that is above a selected threshold, the control circuit subsystem  155  can cause the graphical user interface  142  to display an alert  167  in the form of a textual message or an error code. Further, in some embodiments, the control circuit subsystem  155  may automatically cause the pneumatic subsystem to deflate the balloon device  122  so as to immediately reduce the high pressure in the coronary sinus  20 . 
     Still referring to  FIG. 3 , the pneumatic subsystem  153  of the control system  140  can be configured to promptly inflate or deflate the balloon device  122  in response to the control circuit subsystem. In some embodiments, the pneumatic subsystem may include a reservoir containing pressured gas, such as helium, and a vacuum pump. The reservoir and the vacuum pump can be controlled by a set of valves and are monitored by a set of pressure sensors that feedback into the control circuit subsystem  155 . In such circumstances, the pneumatic subsystem can be configured to inflate or deflate the balloon device  122  at the distal tip portion  121  of the coronary sinus occlusion catheter  120  in less than 1 second, less that about 0.6 seconds, and preferably less than about 0.4 seconds. 
     Referring now to  FIGS. 4-7 , the coronary sinus occlusion catheter  120  carries the inflatable balloon device  122  along its distal tip portion  121  while the proximal hub  132  is arranged along the proximal portion  131 . As previously described, the proximal hub  132  serves as the connection interface between the fluid or sensor lines  133 ,  134 , and  135  ( FIG. 4 ) and the corresponding lumens  123 ,  124 , and  125  ( FIG. 6 ) extending through the catheter  120 . In this embodiment depicted in  FIG. 4 , the coronary sinus pressure sensor line  135  is connected to the proximal hub  132  using a Luer lock  137  so as to maintain the fluid path from the central lumen  125  of the catheter  120  to the lumen of the line  135 . In some embodiments, the hub-to-tip distance (length “a” shown in  FIG. 4 ) can be selected to enable the catheter  120  to be introduced both via the access point at the jugular vein ( FIG. 2 ) and via access point at the femoral vein ( FIG. 2 ). 
     As previously described, the system  100  may include a guide member  110  that is used to direct the coronary sinus occlusion catheter  120  through the venous system and into the heart  10 . Referring to  FIG. 4 , the guide member  110  may be a guide sheath having a central lumen extending from a proximal end  112  ( FIG. 4 ) to a distal end  111  ( FIG. 1 .) As previously described, the guide member  110  may be equipped with a steering mechanism (e.g., steel cables, a shape memory element, or the like) so that the surgeon can more readily advance the guide member  110  through the venous system and into the right atrium. 
     Still referring to  FIGS. 4-7 , the inflatable balloon device  122  of the coronary sinus occlusion catheter  120  may have a predetermined shape when in the inflated condition. In this embodiment, the inflatable balloon device  122  includes a first conical portion narrowing down toward the distal direction, a second conical portion narrowing down toward the proximal direction, and a small generally cylindrical rim portion which is arranged between the conical portions. The narrowed ends of each of the conical portions are connected with the catheter shaft so as to provide a seal that prevents gas leakage from the balloon device  122 . In the inflated condition, the diameter of the balloon device  122  in the region of the cylindrical rim portion is, for example, between about 12 mm and about 22 mm, and preferably about 15 mm. The length “b” of the balloon device is, for example, between about 20 mm and about 30 mm, and preferably about 25 mm. As shown in  FIG. 5 , the coronary sinus occlusion catheter  120  can be equipped with a marker band  128  (positioned inside the balloon device  122  in this embodiment) that comprises an X-ray compatible material so as to be rendered visible during a surgery by suitable imaging processes. 
     As shown in  FIG. 6 , the shaft of the coronary sinus occlusion catheter  120  extending distally from the proximal hub  132  can include a plurality of lumens  123 ,  124 ,  125 , and  126 . In this embodiment, the ring segment-shaped lumen  123  serves to supply and discharge fluid (e.g., helium gas in this embodiment) for inflating and evacuating the balloon device  122 . The ring segment-shaped lumen  124 , which is smaller than the other lumen  123 , likewise communicates with the interior of the balloon device  122  and serves to measure the fluid pressure within the balloon device  122 . The central lumen  125  in this embodiment is employed for measuring the coronary sinus pressure. The central lumen  125  is in fluid communication with the distal ports  129  of the catheter  120  so that the blood pressure in the coronary sinus is transferred to the fluid-filled path extending through the central lumen  125  and to the pressure sensor device  136  ( FIG. 2 ). Alternatively, a miniature pressure sensor can be positioned immediate adjacent to the distal ports  129  such that a sensor wire (e.g., electrical or optical) extends through the central lumen  125  for communication with the control system  140  ( FIG. 2 ). In this embodiment, the shaft of the coronary sinus occlusion catheter  120  includes a fourth lumen  126  having a circular cross section. One or more additional sensors or sensor wires can be positioned in this fourth lumen. Alternatively, a stiffening wire can be arranged in the fourth lumen  126  so as to extend through the catheter shaft in the region of the balloon device  122 . The stiffening wire, which can comprise of a shape memory material such as Nitinol, can be used to facilitate delivery of the distal tip portion  121  into the coronary sinus  20 . 
     Referring to  FIGS. 5 and 7 , the distal ports  129  of the catheter  120  are arranged distally forward of the balloon device  122  and are oriented to face generally radially outward (e.g., not facing axially outward from the end of the catheter  120 ). This tip portion of the coronary sinus occlusion catheter  120  can be configured so that the fluid pressure in the coronary sinus can be accurately measured even if a portion of the distal end abuts against a wall of the coronary sinus. In this embodiment, the distal ports  129  comprise three ports that are evenly spaced apart along the circumference of the tip (which has a slightly conical barrel), thereby enabling the fluid pressure in the coronary sinus to be applied into one or more the ports  129  even if one side of the tip is pressed against a wall of the coronary sinus. 
     Optionally, a hypotube  127  can surround at least a portion the catheter shaft so as to permit the distal tip portion  121  of the catheter  120  to follow the curvatures of the venous system during delivery to the heart  10 . As shown in  FIGS. 5 and 7 , a hypotube  127  can surround at least a portion the catheter shaft at a distance “c” from the proximal end of the balloon device  122 . The hypotube  127  may comprise a helical line-shaped notch formed along its periphery, and the pitch of the helix at the distal portion of the hypotube  127  can be smaller than in a more proximally located region. This results in a reduced flexural strength in the distal portion of the hypotube  127  so as to enable the catheter to follow the curvatures of the venous system during delivery to the heart  10 . 
     Referring now to  FIGS. 8-10 , the system  100  previously described in connection with  FIGS. 1-2  can be configured to pre-treat damaged heart muscle tissue with redistributed venous blood flow before coronary artery blockage  35  repaired or removed. While  FIGS. 8-10  depicted some embodiments of using the system  100  to treat the heart muscle tissue, it should be understood from the description herein that the system  100  can also be employed in alternative procedures where the coronary sinus occlusion catheter  120  does not redistribute the coronary venous blood flow until after the coronary artery blockage  35  is initially accessed for repair or removal. 
     As shown in  FIG. 8 , the distal tip portion  121  of the coronary sinus occlusion catheter  120  can be arranged in the coronary sinus  20  and thereafter activated to occlude the blood flow exiting from the coronary sinus  20  and into the right atrium  11 . As previously describe din connection with  FIG. 1 , the coronary sinus occlusion catheter  120  can be delivered via the venous system to the coronary sinus  20  prior to repairing or treating the blockage  35  the coronary artery  40 . When the inflatable balloon device  122  of the catheter  120  occludes the coronary sinus, the portion of heart muscle tissue  30  that is damaged due to lack of arterial blood flow (as a result of the blockage) can be pre-treated with a supply of venous blood before the normal arterial blood flow is restored (as a result of repairing or removing the blockage  35 ). In particular, the venous blood flow that is normally exiting from the coronary sinus  20  will be redistributed into the portion of heart muscle tissue  30  that has been damaged due to blood deprivation via the local artery  41 . 
     During the period of occlusion of the coronary sinus  20 , other branch veins  22  located at different regions along the heart  10  may continue to receive blood flow, thereby creating a supply of venous blood flow attempting to exit through the coronary sinus  20 . Because the exit from the coronary sinus  20  is occluded by the balloon device  122 , the venous blood flow from the other veins  22  is redistributed to the local vein  21  and then into the portion of heart muscle tissue  30  that is suffering from a lack of blood flow due to the blockage  35  in the coronary artery  40 . This redistributed venous blood flow in the coronary venous system causes the ischemic or otherwise damaged heart muscle tissue  30  to be pre-treated with an improved the supply of nutrients before the blockage  35  is repaired or removed to restore normal coronary arterial blood flow. 
     Still referring to  FIG. 8 , the inflatable balloon device  122  of the coronary sinus occlusion catheter  120  can be intermittently inflated and deflated so as to cause the previously described redistribution of venous blood flow while also preventing the pressure in the coronary sinus from reaching unsafe levels. In particular embodiments, the control system  140  ( FIGS. 2-3 ) can activate and deactivate the balloon device  122  (causing inflation and deflation) according to one of two types of operations: (1) a predetermined pattern of intermittent coronary sinus occlusion (time periods are independent of coronary sinus pressure measurements), or (2) a pressure-controlled intermittent coronary sinus occlusion (time periods are dependent upon the coronary sinus pressure measurements). For example, during an initial phase when the catheter  120  is first delivered into the coronary sinus  20  and initially activated, the control system  140  can inflate and deflate the balloon device  122  according to the predetermined pattern of inflated times and deflated times. One example of the predetermined pattern may be:
         7 seconds of occluded state (balloon device  122  inflated),   3 seconds of non-occluded state (balloon device  122  deflated),   10 seconds of occluded state,   4 seconds of non-occluded state,   12 seconds of occluded state,   3 seconds of non-occluded state,   6 seconds of occluded state,   3 seconds of non-occluded state,   20 seconds of occluded state,   5 seconds of non-occluded state,   14 seconds of occluded state,   3 seconds of non-occluded state,   7 seconds of occluded state,   3 seconds of non-occluded state,   16 seconds of occluded state,   3 seconds of non-occluded state,   10 seconds of occluded state, and   4 seconds of non-occluded state.
 
During these time periods in the initial phase, the coronary sinus pressure measurements are recorded by the control system  140  (and displayed on the user interface  142 ), but the time periods for the occluded state and the non-occluded state are predetermined and do not changed based upon the coronary sinus pressure measurements. These time periods of occlusion and non-occlusion in the initial phase are used gather coronary sinus pressure data, which allows comparisons of the pressure curve at different times and permits the control system  140  to adjust or optimize a cycle length during the next phase (pressure-controlled coronary sinus occlusion). In some cases, the control system  140  repeats the predetermined pattern of occlusion periods and release periods so as to provide a quantitative estimated of changes within the treated heart.
       

     After this initial phase, the control system  140  can automatically switch the second type of operation in which the time periods for the occluded state and the non-occluded state are a function of the previously recorded coronary sinus pressure measurements. For example, the control system  140  can inflate and deflate the balloon device  122  according to the previously described algorithm that assesses a previous set of coronary sinus pressure measurements in a function that estimates the new time period for the next occluded state or non-occluded state. 
     Referring now to  FIG. 9 , when the balloon device  122  of the coronary sinus occlusion catheter  120  is in a deflated condition, the coronary sinus  20  is not occluded and the venous blood flow can resumes its normal path to exit fro the coronary sinus  20  into the right atrium. The blood that was previously redistributed to the damaged portion of the heart tissue  30  can also pass through the venous system and exit out of the coronary sinus  20 . While the venous blood is flushed out of the damaged tissue  30 , at least some portion of the metabolic waste products from the damaged tissue  30  can be carried off at the same time, thereby helping to reduce or eliminate the ischemic tissue infarct size. 
     As shown in the embodiment in  FIG. 9 , after the coronary sinus occlusion catheter  120  intermittently occludes the coronary sinus  20  (e.g., intermittently adjusts between the inflated condition in  FIG. 8  and the deflated condition in  FIG. 9 ) to pre-treat the damaged heart tissue  30 , a different instrument  200  can be advanced into the coronary artery  40  toward the blockage  35 . The blockage treatment instrument  200  can be a percutaneous coronary intervention (PCI) instrument, such as an angioplasty balloon catheter or a stent delivery instrument. In this embodiment, the PCI instrument  200  is in the form of stent delivery instrument which carries a stent device  220  along a distal portion for purposes of treating the blockage  35  in the coronary artery  40 . When the stent device  220  reaches the blockage  35 , the stent device  220  can expand to widen the artery and remove the blockage  35  that disrupted arterial blood flow to the local artery  41  near the damaged heart muscle tissue  30 . 
     It should be understood from the description herein that, in some embodiments, the coronary sinus occlusion catheter  120  may continue to intermittently occlude the coronary sinus (as shown in  FIG. 8 ) during use of the second instrument  200  to treat the arterial blockage  35 . In such circumstances, the balloon device  122  of the coronary sinus occlusion catheter  120  can intermittently occlude the coronary sinus  20  and thereby redistribute the venous blood flow to the damaged portion of the heart muscle tissue  30 . Further, in some embodiments, the coronary sinus occlusion catheter  120  may continue to intermittently occlude the coronary sinus (as shown in  FIG. 8 ) even after the second instrument  200  has completed the procedure to repair or remove the arterial blockage  35 . The duration of time for using the coronary sinus occlusion catheter  120  to intermittently occlude the coronary sinus  20  may be determined by the surgeon based upon a number of factors, including the trend of the coronary sinus pressure measurements (as displayed on the user interface  142 ), a measurement of particular bio-markers present in the patient&#39;s blood (e.g., lactate (which increases in the event of ischemia), potassium (an indicator of ischemic tissue), and the like). 
     Referring now to  FIG. 10 , the coronary sinus occlusion catheter  120  can be removed from the heart  10  some time after the blockage treatment device  200  is employed to repair the blockage in the coronary artery  40 . In circumstances, the guide member  110  can remain in the right atrium while the coronary sinus occlusion catheter  120  is removed. In this embodiment, the guide member  110  comprises a guide sheath, so the internal lumen of the guide sheath  110  may be subject to continued flushing after the coronary sinus occlusion catheter  120  is fully removed from the proximal portion of the guide sheath  110  outside the patient&#39;s body. As described in more detail below, the guide sheath  110  may remain in the right atrium during a post-treatment monitoring period after the coronary sinus occlusion catheter  120  is removed so as to provide simplified access in the event that a new coronary sinus occlusion catheter  120  is required. 
     For example, after the blockage is repaired ( FIG. 9 ) and the coronary sinus occlusion catheter  120  is withdrawn from the body ( FIG. 10 ), the patient&#39;s recovery may be closely monitored for a period of minutes or hours (e.g., about one to about six hours) to determine if additional intermittent coronary sinus occlusion treatment is warranted. During this period, the patient&#39;s biomarkers (e.g., lactate, potassium, and the like) and ECG data can be monitored to determine if the heart&#39;s condition is improving or if additional treatment with a new coronary sinus occlusion catheter  120  is required to treat damaged heart muscle tissue. If, during this post-treatment monitoring period, the patent&#39;s heart condition improves toward a satisfactory recovery, then the guide sheath  110  can be removed from the right atrium  11 . If, during this post-treatment monitoring period, the patent&#39;s heart condition indicates that additional treatment is required using a new coronary sinus occlusion catheter  120 , the new catheter  120  can be promptly advanced through the guide sheath  111  (which was previously employed with the first coronary sinus occlusion catheter  120 ) and into the coronary sinus as shown in  FIG. 1 . In one example, the new coronary sinus occlusion catheter can be employed to perform pressure-controlled coronary sinus occlusion treatment for a period time in an effort to limit or repair reperfusion damage as well as to establish pathways for recovery (e.g., limiting inflammation and inducing regeneration of microcirculation). 
     Referring now to  FIG. 11 , a process  300  of using the previously described system  100  can be implemented in combination with a cardiac interventional procedure for treating a blockage in the heart. For example, in some implementations, the process  300  can include the step  310  of detecting a blockage in a heart, such as a blockage in a coronary arterial of the heart (refer, for example, to  FIG. 1 ). In step  315 , the process  300  may include delivering a guide sheath or other guide member through the venous system and into the right atrium (refer, for example, to the sheath  110  in  FIG. 1 ). Also, in step  320 , the process  300  may include advancing a distal tip portion of a coronary sinus occlusion catheter through the guide sheath and into the coronary sinus. For example, the catheter may be controlled by the control unit  140  so that it operates as a PICSO (pressure-controlled intermittent coronary sinus occlusion) catheter. In step  325 , the process  300  may include the operation of intermittently occluding the coronary sinus using the PICSO catheter to reperfuse heart muscle tissue affected by the blockage (refer, for example, to  FIG. 8 ). The timing of the intermittent occlusion and non-occlusion periods may be automatically controlled by the control unit  140 . 
     The process  300  may include a step  330  of delivering a coronary intervention tool (e.g., a stent device, an angioplasty balloon, or the like) to the blockage in the coronary artery after the PICSO catheter is used to intermittently occlude the coronary sinus. In step  335 , the coronary intervention tool can be used to treat the blockage in the coronary artery. Accordingly, the PICSO catheter described in step  325  can be employed to “pretreat” to the heart tissue affected by the blockage before the blockage is repaired using the coronary intervention tool. 
     Optionally, the process  300  may include the step  340  in which the PICSO catheter is employed to continue to intermittently occlude the coronary sinus during and after the procedure in step  335  where the blockage is treated with the coronary intervention tool. In such circumstances, the heart muscle tissue that was affected by the blockage may continue to be reperfused with venous blood both during and after the procedure to repair the blockage. 
     As shown in step  345  of  FIG. 1 , the PICSO catheter can be withdrawn from the body while the guide sheath remains in the right atrium (refer, for example, to  FIG. 10 ). As previously described, the guide sheath  110  can remain in the right atrium during a post-operative monitoring period so as to provide simplified access to the heart in the event a subsequent PICSO treatment is warranted. For example, in step  350 , the process  300  includes monitoring bodily characteristics of the patient to determine if additional PICSO treatment in warranted. In some cases, blood samples may be tested to monitor bio-markers present in the blood that indicate the extent of ischemia or damaged heart muscle tissue. The measurement of the bio-markers present in the patient&#39;s blood may include a measurement of lactate, potassium, and other indicators of ischemic tissue. Further, the patient&#39;s ECG data can be monitored during this post-operative monitoring period. If the patient&#39;s bodily characteristics indicate that no further PICSO treatment is warranted, the process  300  may proceed to the step  355  in which the guide sheath is withdrawn from the patient&#39;s body. If, however, the patient&#39;s bodily characteristics indicate that additional PICSO treatment is warranted, the process  300  may proceed to step  360  in which a new PICSO catheter is delivered through the previous guide sheath. In this step, a distal tip portion of the new PICSO catheter can be delivered into the right atrium, and the control unit can be employed to cause the new PICSO catheter to intermittently occlude the coronary sinus. In step  365 , the new PICSO catheter can be withdrawn from the body after the additional PICSO treatment while the guide sheath remains in the right atrium (refer, for example, to  FIG. 10 ). The process  300  may then return to step  350  in which the guide sheath  110  can remain in the right atrium during a post-operative monitoring period. 
     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the scope of the invention. Accordingly, other embodiments are within the scope of the following claims.