Abstract:
A valvuloplasty system comprises a balloon adapted to be placed adjacent leaflets of a valve. The balloon is inflatable with a liquid. The system further includes a shock wave generator within the balloon that produces shock waves. The shock waves propagate through the liquid and impinge upon the valve to decalcify and open the valve. The balloon is carried on a catheter that includes a guidewire lumen. The system further includes a debris collecting basket carried on the catheter proximal to the balloon.

Description:
PRIORITY CLAIM 
       [0001]    The present application claims the benefit of copending U.S. Provisional Patent Application No. 61/411,798, filed Nov. 9, 2010, which application is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Aortic calcification, also called aortic sclerosis, is a buildup of calcium deposits on the aortic valve in the heart. This often results in a heart murmur, which can easily be heard with a stethoscope over the heart. However, aortic calcification usually doesn&#39;t significantly affect the function of the aortic valve. 
         [0003]    In some cases, though, the calcium deposits thicken and cause narrowing at the opening of the aortic valve. This impairs blood flow through the valve, causing chest pain or a heart attack. Doctors refer to such narrowing as aortic stenosis. 
         [0004]    Aortic calcification typically affects older adults. But when it occurs in younger adults, it&#39;s often associated with an aortic valve defect that is present at birth (congenital) or with other illnesses such as kidney failure. An ultrasound of the heart (echocardiogram) can determine the severity of aortic calcification and also check for other possible causes of a heart murmur. 
         [0005]    At present there is no specific treatment for aortic calcification. General treatment includes the monitoring for further developments of heart disease. Cholesterol levels are also checked to determine the need for medications to lower cholesterol in the hope to prevent progression of aortic calcification. If the valve becomes severely narrowed, aortic valve replacement surgery may be necessary. 
         [0006]    The aortic valve area can be opened or enlarged with a balloon catheter (balloon valvuloplasty) which is introduced in much the same way as in cardiac catheterization. With balloon valvuloplasty, the aortic valve area typically increases slightly. Patients with critical aortic stenosis can therefore experience temporary improvement with this procedure. 
         [0007]    Unfortunately, most of these valves narrow over a six to 18 month period. Therefore, balloon valvuloplasty is useful as a short-term measure to temporarily relieve symptoms in patients who are not candidates for aortic valve replacement. Patients who require urgent noncardiac surgery, such as a hip replacement, may benefit from aortic valvuloplasty prior to surgery. Valvuloplasty improves heart function and the chances of surviving non-cardiac surgery. Aortic valvuloplasty can also be useful as a bridge to aortic valve replacement in the elderly patient with poorly functioning ventricular muscle. Balloon valvuloplasty may temporarily improve ventricular muscle function, and thus improve surgical survival. Those who respond to valvuloplasty with improvement in ventricular function can be expected to benefit even more from aortic valve replacement. Aortic valvuloplasty in these high risk elderly patients has a similar mortality (5%) and serious complication rate (5%) as aortic valve replacement in surgical candidates. 
         [0008]    The present invention provides an alternative treatment system for stenotic or calcified aortic valves. As will be seen subsequently, the embodiments described herein provide a more tolerable treatment for aortic stenosis and calcified aortic valves than the currently performed aortic valve replacement. The invention also provides a more effective treatment than current valvuloplasty therapy. For patients undergoing trans aortic or catheter based aortic valve replacement the invention can soften, smooth, and open the aortic valve annulus more effectively than current valvuloplasty and prepare the area for the catheter delivered valve. 
         [0009]    Current valvuloplasty therapy can dislodge calcium particles which may flow down stream and cause blockage in smaller arteries. Such blockage can even occur in larger arteries, such as the carotid artery, for example. Carotid artery blockage is especially worrisome because the carotid arteries provide blood to the brain. Any blockage in a carotid artery could result in stroke or even death. 
       SUMMARY OF THE INVENTION 
       [0010]    The invention provides a valvuloplasty system comprising a balloon adapted to be placed adjacent leaflets of a valve. The balloon is inflatable with a liquid. The invention further comprises an embolic protection basket and a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the valve. The embolic protection basket is arranged for collecting debris resulting from the shock waves impinging upon the valve. 
         [0011]    The embolic protection basket is self-deployable. The system may further comprise an elongated tube. The balloon may be carried by the elongated tube and the embolic protection basket may also be carried on the elongated tube. The balloon may be at a distal end of the elongate tube and the embolic protection basket may be carried on the elongated tube proximal to the balloon. The embolic protection basket may include a tubular extension extending proximally from the embolic protection basket. The embolic protection basket and the tubular extension may be carried on the elongated tube. 
         [0012]    The shock wave generator may include a first electrical arc generator and a second electrical arc generator. The electrical arc generators may comprise at least one electrode adapted for connection to a voltage pulse generator. Each of the electrical arc generators may comprise an electrode pair adapted for connection to a voltage pulse generator. 
         [0013]    The system may further comprise an elongated tube having a lumen. The balloon may be carried by and about the elongated tube. The system may further include a guidewire adapted to slidingly receive the lumen of the elongated tube. 
         [0014]    The embolic protection basket may be carried on the elongated tube. The balloon and the embolic protection basket may be arranged on the elongated tube such that when the balloon is within the leaflets of an aortic valve, the embolic protection basket is distal to a brachiocephalic trunk. The system may further comprise an elongated over tube arranged to be received over the elongated tube, the balloon, and the embolic protection basket. The embolic protection basket and the balloon may be arranged to be in a collapsed state while being in the over tube. The system embolic protection basket may be further arranged to expand into a deployed state when exiting the over tube. 
         [0015]    The invention further provides a valvuloplasty system comprising an elongated tube having a proximal end, a distal end, and a longitudinal lumen extending there through and a balloon carried on the distal end of the elongated tube and adapted to be placed adjacent leaflets of a valve. The balloon is inflatable with a liquid. The system further comprises a guidewire slidingly received by the longitudinal lumen of the elongated tube for guiding the elongated tube and the balloon along a desired path and a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the valve. 
         [0016]    The system may further comprise an embolic protection basket carried on the elongated tube proximal to the balloon. The shock wave generator comprises an electrical arc generator. The electrical arc generator may comprise at least one electrode adapted for connection to a voltage pulse generator. 
         [0017]    The invention still further provides a valvuloplasty method of treating a valve having leaflets and an annulus. The method comprises the steps of placing a balloon adjacent to the leaflets of the valve, placing an embolic protection basket proximal to the balloon, and inflating the balloon with a liquid. The method further includes the steps of producing shockwaves within the balloon that propagate through the liquid for impinging upon the valve leaflets and the valve annulus, and capturing debris resulting from the shockwaves impinging upon the valve annulus and leaflets within the embolic protection basket. 
         [0018]    The placing step may be performed by placing the balloon on opposite sides of the valve leaflets. Alternatively, the placing step is performed by placing the balloon within the valve annulus. 
         [0019]    The invention still further provides a valvuloplasty method for treating a valve having leaflets and an annulus comprising the steps of providing an elongated tube having a proximal end, a distal end, and a longitudinal lumen extending there through, a balloon, inflatable with a liquid, carried on the distal end of the elongated tube and adapted to be placed adjacent leaflets of a valve, a guide wire, and a shock wave generator within the balloon that produces shock waves that propagate through the liquid for impinging upon the valve and advancing the guide wire along a desired path through the valve annulus. The method further includes the steps of sliding the elongated tube onto the guide wire, advancing the elongated tube on the guide wire until the balloon is adjacent the valve leaflets, inflating the balloon with the liquid, and producing shockwaves within the balloon with the shock wave generator. 
         [0020]    The method may further comprise the further steps of providing the elongated tube with an embolic protection basket proximal to the balloon, and capturing debris resulting from the shockwaves impinging upon the valve annulus and leaflets within the embolic protection basket. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The various described embodiments of the invention, together with representative features and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify identical elements, and wherein: 
           [0022]      FIG. 1  is a cut away view of the left ventricle, the aorta, and the aortic valve of a heart showing a reduced aortic valve open area and thickened valve leaflets due to calcium and fibrotic tissue; 
           [0023]      FIG. 2  is a cut away view of the aortic valve of a heart with a treatment balloon placed on both sides of the aortic valve leaflets, according aspects of the present invention; 
           [0024]      FIG. 3  is a schematic view of a valvuloplasty system employing a dual shockwave balloon according to aspects of the invention; 
           [0025]      FIG. 4  is a cut away view of a heart showing an alternate valvuloplasty shock wave balloon according to a further aspects of the present invention; 
           [0026]      FIG. 5  is cut away view of a valvuloplasty system including a shockwave balloon, deployed in relation to aortic valve leaflets, having a center guide lumen sized to be received over a guide wire and a guide tube which is used to deliver the shockwave balloon to the desired area of the heart according to further aspects of the invention; 
           [0027]      FIG. 6  is a cut away view of a heart showing the balloon of  FIG. 5  in position about the aortic valve leaflets and carried on the guide wire; and 
           [0028]      FIG. 7  is a partial cut away view of a heart to an enlarged scale showing an aorta with a balloon of a valvuloplasty system according to the invention positioned within the aortic valve and an embolic protection basket deployed with respect to the balloon to capture debris resulting from a valvuloplasty procedure performed with the valvuloplasty system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Referring now to  FIG. 1 , it is a cut away view of the left ventricle  12 , the aorta  14 , and the aortic valve  16  of a heart  10  with a stenotic and calcified aortic valve  16 . Here more particularly, it may be seen that the opening  17  of the stenotic and calcified aortic valve  16  is restricted in size and that the valve leaflets  18  are thickened with calcium deposits and fibrotic tissue. The thickened leaflets  18  and smaller valve opening  17  restrict blood flow from the heart creating excess work for the heart  10  and poor cardiac output. As previously mentioned, current treatment includes replacement of the valve or attempts to stretch the valve annulus with a balloon. 
         [0030]      FIG. 2  is a cut away view of the aortic valve  16  with a treatment balloon  22  placed on both sides of the aortic valve leaflets  18 . The balloon  22  may be formed from a compliant or a non-compliant material. The balloon, as seen in  FIG. 2 , is at the distal end of an elongated tube  23 . The treatment balloon  22  has two longitudinally spaced chambers  24  and  26  that share a common inflation lumen  25  of the tube  23 . Alternatively the balloon chambers  24  and  26  may not share the same inflation fluid path. The chambers  24  and  26  are longitudinally spaced such that chamber  24  is positioned on one side of the aortic valve leaflets  18  and chamber  26  is positioned on the other side of the aortic valve leaflets  18 . The chambers  24  and  26  are inflated with saline/contrast mixture, for example. Each chamber  24  and  26  may contain an electrode (as shall be seen subsequently) that can produce electrical arcs to deliver timed shock waves. The shock waves can be synchronized to concurrently impinge upon both sides of the leaflets  18  to maximize the effectiveness of breaking calcium deposits. Such shock waves may be generated and also synchronized to the R wave of the heart  10  in a manner as described for example in co-pending application No. 61/061,170 filed on Jun. 13, 2008, which application is incorporated herein in its entirety. 
         [0031]      FIG. 3  is a schematic view of a valvuloplasty system  11  that includes the dual shockwave balloon  22 . The balloon  22  has received a high voltage catheter  32  that is connected to a high voltage power supply  30 . The schematic representation shows the positioning of the balloon chambers  24  and  26  above and below the leaflets  18  of the aortic valve  16 . As previously described, shock waves will impinge upon opposite sides of the leaflets  18  to more effectively break calcium deposits in the valve leaflets  18 . The annulus will also be treated in this arrangement. To that end, the high voltage catheter  32  includes electrode pairs  34  and  36  that are coaxially arranged electrodes placed in chambers  24  and  26  respectively of the balloon  22 . More specifically, electrode pair  34  is at the distal end of a first cable and comprises a center conductor  33  and an outer conductive shield  35 . Similarly, electrode pair  34  is at the distal end of a second cable and comprises a center conductor  37  and an outer conductive shield  39 . High voltage pulses from power supply  30  are applied to the electrode pairs  34  and  36  in a manner as described in the aforementioned application Ser. No. 61/061,170 to create shockwaves within the fluid within the chambers  24  and  26  of the balloon  22 . The shock waves impinge upon the valve leaflets  18  and the valve annulus to cause the break up of calcium deposits and fibrotic tissue on the valve leaflets  18  and annulus to open and smooth the aortic valve  16 . 
         [0032]      FIG. 4  shows an alternate valvuloplasty shock wave balloon  42  at the distal end of an elongated tube  43 . The balloon  42  is placed in the annulus of the aortic valve  16 . To that end, the balloon  42  has a reduced diameter portion  45  for being received within the valve annulus. The balloon  42  has a high voltage catheter  44  therein that terminates in an electrode pair  46 . As in the previous embodiment, the electrode pair  46  may comprise a pair of coaxially arranged electrodes where a center conductor may form at least a part of one electrode and at an outer conductive shield may form at least a part of the other electrode. The catheter  44  and its electrode pair  46  provide shock waves as previously described. Such an arrangement will decalcify the leaflets  18 . This not only will decalcify the leaflets  18 , but will also soften the aortic valve annulus and expand its diameter. Hence, the balloon  42  provides the added advantage of exerting expansion pressure directly to the annulus of the valve to remodel the annulus diameter. 
         [0033]      FIG. 5  is a cut away view of a valvuloplasty system  50  embodying the present invention including a shockwave balloon  52  deployed on both sides of the aortic valve leaflets  18 . The balloon  52  may be formed from a compliant or a non-compliant material. The balloon, as seen in  FIG. 5 , is at the distal end of an elongated tube  53 . The treatment balloon  52  has two longitudinally spaced chambers  54  and  56  that share a common inflation lumen  55  of the tube  53 . Alternatively the balloon chambers  54  and  56  may not share the same inflation fluid path. The chambers  54  and  56  are longitudinally spaced such that chamber  54  is positioned on one side of the aortic valve leaflets  18  and chamber  56  is positioned on the other side of the aortic valve leaflets  18 . The chambers  54  and  56  may be inflated with saline/contrast mixture, for example. 
         [0034]    The system  50  further includes a shockwave generator including electrical arc generators  60  and  62 . Each of the electrical arc generators  60  and  62  includes an electrode pair  64  and  66 , respectively. The electrode pairs may include coaxially disposed electrodes similar to the electrodes of electrode pairs  34  and  36  of  FIG. 3 . 
         [0035]    Each balloon chamber  54  and  56  contains one of the electrodes pairs. As seen in  FIG. 5 , balloon chamber  54  has electrode pair  64  and balloon chamber  56  has electrode pair  66 . The elongated tube  53  further includes a center guide lumen  70 . The center guide lumen is sized to fit over a guide wire  72 . Also, shown is a guide tube  80  which is used to deliver the shockwave balloon to the desired area of the heart. 
         [0036]    As in previous embodiments, the balloon chambers  54  and  56  may be expanded with a mixture of saline and contrast which aides in shock formation and visualization via x-ray. An added benefit to contrast is the absorption of UV light waves generated by the arc of the shockwave generators. 
         [0037]    The shock waves can be synchronized to concurrently impinge upon both sides of the leaflets  18  to maximize the effectiveness of breaking calcium deposits. Such shock waves may be generated and also synchronized to the R wave of the heart  10  in a manner as described for example in co-pending application No. 61/061,170 filed on Jun. 13, 2008, which application is incorporated herein in its entirety. 
         [0038]      FIG. 6  is a cutaway view showing the system  50  of  FIG. 5  with the balloon in position about the aortic valve  18  and carried on the guide wire  72 . The guide wire  72  is placed through the aortic valve and in the left ventricle  12  to direct the placement of the system  50 . For simplicity the electrodes are not shown in  FIG. 6 . 
         [0039]      FIG. 7  is a partial cut away view of the aorta and the aortic valve of a heart to an enlarged scale together with a valvuloplasty system embodying the invention. The valvuloplasty system shown in  FIG. 7  is the valvuloplasty system  50  of  FIG. 5  but further including an embolic protection basket  90  carried on the elongated tube  53  proximal to the balloon  52 . The embolic protection basket  90  is also deployed on the elongated tube  53  distal to the brachiocephalic trunk  102 , the common carotid artery  104  and the subclavian artery  106 . With the embolic protection basket thus positioned, it will capture debris resulting from a valvuloplasty procedure performed with the valvuloplasty system  50  and prevent such debris from entering the brachiocephalic trunk  102 , the common carotid artery  104  or the subclavian artery  106 . 
         [0040]    The embolic protection basket  90  may be fixed to the elongated tube  53 . Alternatively, the basket may include a proximal extension  92  to permit the basket  90  to be slidingly disposed on the elongated tube  53 . This would allow the relative distance between the basket  90  and the balloon  52  to be adjusted. 
         [0041]    The basket preferably has an umbrella-like structure  94  formed of nitinol, for example. As is well known, nitinol has shape memory permitting the basket to be placed into the introduction guide tube  80  in a collapsed state. When the guide tube  80  is pulled back, the basket  90  will be freed and expand from the collapsed state to an expanded and deployed state as shown. 
         [0042]    In use of the system  50  and the embolic protection basket  90 , the guide wire  72  is first advanced into the heart and through the aortic valve leaflets  18 . The distal tip of the guide wire will extend into the left ventricle  12 . Next, the guide tube  80  is advance over the guide wire  72  until it is just past the valve leaflets  18 . The system  50 , together with the embolic protection basket  90  is then guided down the guide tube  80  on the guide wire  72 . Once the balloon  52  is adjacent the valve leaflets  18 , the guide tube is pulled back to expose the balloon  52 . The guide tube is pulled back further until the embolic protection basket  90  is exposed. This frees the basket to expand from the collapsed state to the expanded deployed state. The balloon  52  may now be inflated to form the chambers  54  and  56 . 
         [0043]    Electrical energy pulses may now be applied to the system  50  to create shock waves in the balloon chambers  54  and  56 . As previously described, the shock waves can be synchronized to concurrently impinge upon both sides of the leaflets  18  to maximize the effectiveness of breaking calcium deposits. Such shock waves may be generated and also synchronized to the R wave of the heart in a manner as previously described. During the procedure, the basket captures debris dislodged by the shock waves to protect against such debris from entering the brachiocephalic trunk  102 , the common carotid artery  104  or the subclavian artery  106  (and hence the brain) while at the same time allowing blood to flow through those arteries. After use, the system  50  and debris can be retracted into the over tube  80  and removed from the body. 
         [0044]    While particular embodiments of the present invention have been shown and described, modifications may be made, and it is therefore intended to cover all such changes and modifications which fall within the true spirit and scope of the invention.