Source: https://patents.google.com/patent/WO2000042919A1/en
Timestamp: 2019-08-19 13:29:01
Document Index: 269038415

Matched Legal Cases: ['art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art 12', 'art.\n8', 'art.\n13']

WO2000042919A1 - Anterior and inferior segment cardiac restoration apparatus and method - Google Patents
Anterior and inferior segment cardiac restoration apparatus and method Download PDF
WO2000042919A1
WO2000042919A1 PCT/US2000/001596 US0001596W WO0042919A1 WO 2000042919 A1 WO2000042919 A1 WO 2000042919A1 US 0001596 W US0001596 W US 0001596W WO 0042919 A1 WO0042919 A1 WO 0042919A1
PCT/US2000/001596
Buckberg Gerald D
Athanasuleas Constantine L
1999-01-22 Priority to US09/235,664 priority
2000-01-21 Application filed by Buckberg Gerald D, Athanasuleas Constantine L filed Critical Buckberg Gerald D
2000-07-27 Publication of WO2000042919A1 publication Critical patent/WO2000042919A1/en
ANTERIOR AND INFERIOR SEGMENT CARDIAC RESTORATION APPARATUS
The function of a heart in an animal is primarily to deliver life-supporting oxygenated blood to tissue throughout the body. This function is accomplished in four stages, each relating to a particular chamber of the heart.
Initially deoxygenated blood is received in the right auricle of the heart. This deoxygenated blood is pumped by the right ventricle of the heart to the lungs where the blood is oxygenated. The oxygenated blood is initially received in the left auricle of the heart and ultimately pumped by the left ventricle of the heart throughout the body. It can be seen that the left ventricular chamber of the heart is of particular importance in this process as it is relied upon to pump the oxygenated blood initially through a mitral valve into and ultimately throughout the entire vascular system.
As the ischemic area loses its contraction, the area of dilatation is restricted to the remaining muscle. The three regions of typical infraction include, 1) the anterior wall septum and anterolateral wall which are supplied by the anterior descending coronary artery; 2) the septum and inferior wall supplied by the left anterior artery and the right coronary artery which narrows due to the heart ' s elliptical shape; and 3) the lateral wall supplied by the circumflex artery which perfuses the lateral wall including the papillary muscle attachments to the ventricular wall.
As the ischemic cardiomyopathy progresses, the various structures of the heart are progressively involved including the sternum, the apex and the anterolateral wall of the left ventricle. Within a particular wall, the blood starvation begins at the inside of the wall and progresses to the outside of the wall . It can be seen that addressing ischemic cardiomyopathy shortly after the heart attack can limit the detrimental effects to certain elements of the heart structure, as well as the inner most thicknesses of the walls defining those structures.
Perhaps the most notable symptom of ischemic cardiomyopathy is the reduction in the ejection fraction which may diminish, for example, from a normal sixty percent to only twenty percent. This results clinically in fatigue, and inability to do stressful activities, that require an increase in output of blood from the heart . The normal response of the heart to a reduction in ejection fraction is to increase the size of the ventricle so that the reduced percentage continues to deliver the same amount of oxygenated blood to the body. By way of example, the volume of the left ventricle may double in size. Furthermore, a dilated heart will tend to change its architecture from the normal conical or apical shape, to a generally spherical shape. The output of blood at rest is kept normal, but the capacity to increase output of blood during stress (i.e., exercise, walking) is reduced. Of course, this change in architecture has a dramatic effect on wall thickness, radius, and stress on the heart wall. In particular, it will be noted that absent the normal conical shape, the twisting motion at the apex, which can account for as much as one half of the pumping action, is lost. As a consequence, the more spherical architecture must rely almost totally on the lateral squeezing action to pump blood. This lateral squeezing action is inefficient and very different from the more efficient twisting action of the heart . The change in architecture of the heart will also typically change the structure and ability of the mitral valve to perform its function in the pumping process .
Valvular insufficiency can also occur due to dilatation.
With inferior coronary artery involvement, the inferior wall, septum, and apex are affected. These elements form, naturally a myocardial triangle, with a base adjacent to the mitral valve, and the septum and free lateral walls forming the planes going to the cardiac apex. As the triangle becomes widened, due to loss of contracting muscle after infraction, the same form of ventricular dilatation occurs. However, instead of making the oval ventricle into a sphere in the anterior segment, with subsequent enlargement (dilatation) of the non-infarcted remaining contracting muscle, there is an increase in the triangle inferiorly. As a result, there is an increase in both the transverse diameter as well as the longitudinal dimension. Thus, inferior coronary involvement results in dilatation of the entire inferior segment. Although the dilated heart may be capable of sustaining life, it is significantly stressed and rapidly approaches a stage where it can no longer pump blood effectively. In this stage, commonly referred to as congestive heart failure, the heart becomes distended and is generally incapable of pumping blood returning from the lungs. This further results in lung congestive and fatigue. Congestive heart failure is a major cause of death and disability in the United States where approximately 400,000 cases occur annually.
Following coronary occlusion, successful acute reperfusion by thrombolysis, (clot dissolution) percutaneous angioplasty, or urgent surgery can decrease early mortality by reducing arrhythmias and cardiogenic shock. It is also known that addressing ischemic cardiomyopathy in the acute phase, for example with reperfusion, may salvage the epicardial surface . Although the myocardium may be rendered akinetic, at least it is not dyskinetic. Post-infarction surgical revascularization can be directed at remote viable muscle to reduce ischemia. However, it does not address the anatomical consequences of the akinetic region of the heart that is scarred. Despite these techniques for monitoring ischemia, cardiac dilation and subsequent heart failure continue to occur in approximately fifty percent of post- infarction patients discharged from the hospital.
In a further procedure, a round, circular patch has been proposed for placement typically in the lateral ventricular wall. Unfortunately, providing the patch with a circular shape has allowed the dilated heart to remain somewhat enlarged with a thin and over-stressed wall section. The exact placement of the patch has been visually determined using only a visual indication where the typically white scar tissue meets the typically red normal tissue. Location of the patch has been facilitated in a further procedure where a continuous suture has been placed around the ventricular wall to define a neck for receiving the patch. The neck has been formed in the white scar tissue rather than the soft viable muscle. This procedure has relied on cardioplegia methods to stop the beating of the heart and to aid in suture placement . In the past, the patch has been provided with a fixed or semi-rigid wall which has prevented the muscle from becoming reduced to an apical anchor which facilitates the twisting motion. The patches have had a fixed planar configuration which have prevented the lateral muscle from coapting to form an apex.
These surgical procedures have been met with some success as the ejection fraction has been increased, for example, from twenty-four percent to forty-two percent. However, despite this level of success, little attention has been paid to myocardial protection, the potential for monitoring the writhing action associated with apical structure, or the preferred structure for the patch.
Failure to protect the heart during restoration of the segment has increased hospital mortality, morbidity, and irreversibly damaged some normal muscle needed to maintain the heart ' s output .
A non-circular, anatomically-shaped, typically oval patch is proposed and may be formed of a sheet material such as mammalian fixed pericardium. The patch may include a continuous ring which separates the body of the material from a hemostatic rim or flange which facilitates bleeding control . The patch is fixed to the Fontan neck preferably using pledgeted, interrupted sutures to secure patch placement and avoid distortion. Closure of the excluded ventricle over the hemostatic patch avoids dead space and provides security against patch leaks and resulting expansion.
For anterior infarction, the Fontan suture will change the spherical circular muscle evident by ventricular opening, to an oval configuration which conforms more precisely to the elliptical or gothic ventricular configuration .
For inferior infarction, the endoventricular suture is placed to reform the triangle ( i . e . , septum, apex, inferior wall) that becomes enlarged by the noncontractile muscle after infarction. This muscle can either appear normal, be scarred trabecularly, or scarred completely to diverge from the normal triangular smaller size configuration. The intent is to "retriangulate" the inferior wall to its more normal configuration.
The restoration of an anatomically shaped apex with an oval patch may include the conical configuration of the patch to ensure progressive re-creation of the cone by the improving muscle. For this reason, the ring (attached to the more normal remaining muscle but not the contracting muscle) should be completely pliable (not rigid or semirigid) to allow reformation of the cone by contracting muscle. As cardiac output improves with ventricular volume reduction and wall motion, contractility increases during healing. A semi-rigid cone or apical patch can fix this transverse diameter to prevent coaptation.
These and other features and advantages of the invention will become more apparent with a description of preferred embodiments and reference to the associated drawings .
Fig. 1 is a perspective view of the abdominal cavity of a human body showing the heart in cross section; Fig. 2 is a front plan view of the heart showing coronary arteries which feed the septum, apex and lateral wall of the myocardium;
Fig. 4 is an anterior elevation view of the heart with an incision into the left ventricle through dyskinetic scar tissue; Fig. 5 is an anterior elevation view similar to Fig. 4 where the incision is made in marbled akinetic tissue;
Fig. 8 is an axial cross section view similar to Fig. 7 illustrating the palpating heart and a preferred zone of placement for a patch associated with the present invention;
Fig. 11 is a side elevation view of the opening illustrated in Fig. 9 with the Fontan suture tightened to facilitate the natural oval formation of the opening; Fig. 12A is a plan view of sheet material included in one embodiment of the patch associated with the present invention;
Fig. 12B is a cross section view taken along lines
12B-12B of Fig. 12A and illustrating the sheet material in a concave configuration;
Fig. 21 is an anterior elevation view similar to Fig. 11 and illustrating the placement of pledgeted, interrupted sutures engaging the patch in a remote location; Fig. 22A is an axial cross section view of the left ventricle illustrating the patch being moved along the interrupted sutures from the remote location to the Fontan neck;
Fig. 22B is a perspective view similar to Fig. 21 and illustrating an alternative method for placement of interrupted sutures ;
Fig. 28 is a front perspective view of a preferred embodiment of an inferior patch being sutured to the heart of Fig. 27; Fig. 29 is a front elevation view similar to Fig. 28 and illustrating final placement of the patch with a circumferential rim extending outwardly of the ventricle along the inner surface of the inferior wall; and
Abdominal portions of the human body are illustrated in Figure 1 and designated by the reference numeral 10. The body 10 is merely representative of any mammalian body having a heart 12 which pumps blood containing nutrients and oxygen, to vitalize tissue in all areas of the body 10.
Other organs of particular importance to this blood circulation process include the lungs 14 and 16, and the vasculature of the body 10 including arteries which carry blood away from the heart 12 and veins which return blood to the heart 12.
The pumping of the blood from the left ventricle 25 is accomplished by two types of motion. One of these motions is a simple squeezing motion which occurs between the lateral wall 38 and the septum 41 as illustrated by the arrows 43 and 45, respectively. The squeezing motion occurs as a result of a thickening of the muscle fibers in the myocardium. This compresses the blood in the ventricle chamber 25 and ejects it into the body 10. The thickening is reduced in diastole (when the heart is contracting) and increased in systole (when the heart is ejecting) . This is seen easily by echocardiogram, and can be routinely measured.
Recent studies by MRI show that twisting in systole accounts for approximately 80% of stroke volume, while untwisting (in diastole) accounts for 80% of left ventricle filling. This twisting and untwisting occurs in the same muscle segments, as the ventricle shortens during ejection and lengthens after blood is ejected. The amount of blood pumped from the left ventricle 25 divided by the amount of blood available to be pumped is referred to as the ejection fraction of the heart 12. Generally, the higher the ejection fraction the more healthy the heart. A normal heart, for example, may have a total volume of one hundred milliliters and an ejection fraction of sixty percent. Under these circumstances, 60 milliliters of blood are pumped with each beat of the heart 12. It is this volume of blood in the normal heart of this example, that is pumped with each beat to provide nutrients including oxygen to the muscles and other tissues of the body 10.
The muscles of the body, of course, include the heart muscle or myocardium which defines the various chambers 18-25 of the heart 12. This heart muscle also requires the nutrients and oxygen of the blood in order to remain viable . With reference to Figure 2, it can be seen that the anterior or front side of the heart 12 receives oxygenated blood through a common artery 50 which bifurcates into a septal artery branch 52, which is directed toward the septum 41, and an anterior descending artery 54 which is directed toward the apex 37 and the lateral ventricle wall 38. The inferior wall 44 is supplied by the right coronary artery which also perfuses the septum 41. This wall 44 forms a triangle which extends from the base 35 to the apex
37. Consequently, the apex 37 is supplied by both the anterior descending artery and the right coronary artery.
As the ischemia progresses through its various stages, the affected myocardium dies losing its ability to contribute to the pumping action of the heart. The ischemic muscle is no longer capable of contracting so it cannot contribute to either squeezing or the twisting motion required to pump blood. This non-contracting tissue is said to be akinetic. In severe cases the akinetic tissue, which is not capable of contracting, is in fact elastic so that blood pressure tends to develop a bulge or expansion of the chamber. This is particularly detrimental as the limited pumping action available, as the heart 12 loses even more of its energy to pumping the bulge instead of the blood. The body's reaction to ischemic infraction is of particular interest. The body 10 seems to realize that with a reduced pumping capacity, the ejection fraction of the heart is automatically reduced. For example, the ejection fraction may drop from a normal sixty percent to perhaps twenty percent. Realizing that the body still requires the same volume of blood for oxygen and nutrition, the body causes its heart to dilate or enlarge in size so that the smaller ejection fraction pumps about the same amount of blood. As noted, a normal heart with a blood capacity of seventy milliliters and an ejection fraction of sixty percent would pump approximately 42 milliliters per beat.
The body seems to appreciate that this same volume per beat can be maintained by an ejection fraction of only thirty percent if the ventricle 25 enlarges to a capacity of 140 milliliters. This increase in volume, commonly referred to as "remodeling" not only changes the volume of the left ventricle 25, but also its shape. The heart 12 becomes greatly enlarged and the left ventricle 25 becomes more spherical in shape losing its apex 37 as illustrated in Figure 3. In this view, the stippled area of cross section shows the ischemic or infracted region of the myocardium. On the level of the muscle fibers, it has been noted that dilation of the heart causes the fibers to reorient themselves so that they are directed away from the inner heart chamber containing the blood. As a consequence, the fibers are poorly oriented to accomplish even the squeezing action as the lines of force become less perpendicular to the heart wall. It will be noted that this change in fiber orientation occurs as the heart dilates and moves from its normal elliptical shape to its dilated spherical shape. The spherical shape further reduces pumping efficiency since the fibers which normally encircle the apex to facilitate writhing are changed to a more flattened formation as a result of these spherical configurations. The resulting orientation of these fibers produce lines of force which are also directed laterally of the ventricle chamber 25. Thus, the dilatation and resulting spherical configuration greatly reduce contraction efficiency. It also raises myocardial oxygen demands as torsional defamation (strain) increases.
When a remote muscle is supplied by a non-occluded vessel under stress, the remote muscle tends to contract inefficiently.
Ventricular volume is not excessive or >100 ml/m2 left ventricular end systolic volume. The akinetic lateral wall may contain non-functional (contractile tissue) that is hibernating. This indicates viable tissue that improves contraction several months after complete revascularization or when ventricular volume is reduced to produce a more normal ventricular contour (i.e., ellipse). This recovery after revascularization can occur only when ventricular volume is not very large, or the left ventricular end systolic volume index >100 ml/m2. This aspect of recovery of akinetic hibernating muscle is potentially important when the ventricular shape is changed surgically to go from a sphere (failing heart) to a conical or apical (more normal configuration) contour.
In some cases, the tissue surrounding the incision 61 will be somewhat marbled as illustrated in Figure 5 with patches of both scar tissue 63 and viable red tissue 65. This marbled tissue is often characterized by trabeculae 67 which form ridges along the inner surface or endothelium of the wall . In spite of the presence of some viable tissue 65, these marbled walls of the heart 12 may nevertheless be akinetic .
With reference to Figure 6, it is apparent that the akinetic portion of the myocardium may even appear to be viable with an absence of white scar tissue and the presence of a full red color. Nevertheless, these portions are akinetic and offer no positive effect to the pumping process . Given these factors, it is apparent that a determination as to where the akinetic portions begin and end cannot be a visual determination as relied on by the prior art. Although the visual appearance may be of some value in this determination, ultimately, one must palpate the tissue as illustrated in Figure 7. Note that this emphasizes the importance of performing the restorative surgery on a beating heart . By palpating the myocardial wall, one can feel where the contractions of the lateral ventricular wall 38 and the septum 41 begin and end.
Without regard for color or other properties visually distinguishable, the palpating will usually indicate viable tissue on one side of an imaginary circumferential line 70, with akinetic and dyskinetic tissue on the other side of the imaginary line 70. As described in greater detail below, a patch 72 will ultimately be positioned relative to this imaginary circumferential line 70 not only to reduce the volume of the left ventricle 25 but also to define that reduced volume with a larger percentage of viable heart muscle .
Providing the patch 72 with a configuration complimentary to the ovoid shape of the Fontan stitch 74 is believed to be of particular importance and advantage to the present invention. In the past, patches of a round, circular form were used. This form maintained the fibers in their less efficient transverse orientation. This was especially true of rigid and semi-rigid patches. As a result, the fiber contraction continued to be very inefficient. Providing the patch with an oval configuration restores the apex 37 or elliptical form of the heart 12. On a muscle fiber level, the fibers are directed back to the more efficient 60 degree orientation which produces lines of force more perpendicular with respect to the heart wall 38.
The sheet material 81 may be formed, for example, from Dacron (Hemoshield) , or polytetrafluroethylene (Gortex) .
However, in a preferred embodiment, the sheet material 81 is formed of autologous pericardium, or some other fixed mammalium tissue such as bovine or porcine pericardium. Importantly, the sheet material 81 is preferably sized and configured with a shape similar to that of the Fontan neck 78 as illustrated in Figure 11. As noted, this shape is non-circular and preferably oval. The sheet material 81 can have a generally flat planar configuration, or can be shaped as a section of a sphere.
The spherical shape can be achieved as illustrated in Figure
12B by fixing the pericardium while it is stretched over a spherical die to form a concave surface 90.
The ring 87 can be attached to the material 81 by adhesive or by stitches 97 passing over the ring 87 and through the material 81. Alternatively, the ring 87 can be sandwiched between two pieces of the sheet material . In this case, a second piece of the sheet material 99 can be positioned on the side of the ring 87 opposite to the sheet material 81. Appropriate sutures extending around the ring 87 and through the materials 81 and 99 will sandwich the ring and maintain it in the preferred position. The second piece of material 99 can be formed as a circle with an inner diameter 100 less than that of the ring 87, and an outer diameter 102 generally equal to that of the material 81.
It will be appreciated that many variations on these preferred embodiments of the patch 82 will be apparent, each having a generally non-circular sheet material, such as the material 81, and perhaps a somewhat flexible toroid or oval ring 87. In a preferred method for placing the patch 72, interrupted sutures 105 can be threaded through the Fontan neck 78 as illustrated in Figure 21. Where the tissue is soft, the sutures 105 can be looped through pledgets 110 on the interior side of the neck 78 with the free ends of the sutures 105 extending through the exterior side of the neck 78. These free ends, emanating from progressive positions around the circumferential neck 78, are passed in complementary positions through the body of the patch 72 which is initially positioned remotely of the neck 78 as illustrated in Figure 21. Since the Fontan stitch 74 maybe applied to normal (although akinetic) tissue, the pledgets
110 are preferred to insure that the sutures 105 are well anchored in the neck 78.
With the patch 72 suitably placed, the operative site can be closed by joining the myocardial walls in a pants- over-vest relationship as illustrated in Figure 24. Care should be taken not to distort the right ventricle 21 by folding the septum over the wall 41 ventricular wall 38. Alternatively, the lateral wall 38 can be disposed interiorly of the septum wall 41 so a majority of the force on the patch 72 is diverted to the lateral wall 38. These walls 38 and 41 can be overlapped in close proximity to the patch 72 in order to avoid creating any cavity between the patch 72 and the walls 38, 41. When air evacuation is confirmed by transesophageal echo, the patient can be weaned off bypass usually with minimal, if any, inotropic support. Decanulasation and closure is routine.
Figure 24 is positioned in proximity to Figure 3 in order to illustrate the dramatic difference between the pre- operative dilated heart of Figure 3 and the post-operative apical heart of Figure 24. For comparison it will again be noted that the dilated heart of Figure 3 might typically have a left ventricular volume of 140 milliliters which might produce a blood flow of 42 milliliters with an ejection fraction of 30%. Comparing this with the postoperative heart of Figure 24, it can be seen initially that the ventricular volume is reduced for example to 90 milliliters. The percentage of viable heart wall as opposed to akinetic heart wall is greatly increased thereby providing an increase in the ejection fraction, for example from thirty percent to forty-five percent. This combination results in a pumped blood volume of about 40 milliliters with each beat of the heart 12.
It may be found that muscle function will be restored to some remote areas following the altered ventricular architecture. Although not fully understood, it is believed that this restoration procedure improves remote segmental myocardial contractility by reducing the wall tension and stress in the myocardium due to a reduction in ventricular volume. The stress equation states that --
2h where
R is radius of the heart wall; and h is wall thickness.
The late recovery of hibernating muscle, which may be present in akinetic muscle whose fiber orientation is directed helically (toward the newly created apex) . This progressive shape change may provide further improvement in contractile function several months after restoration. Reducing the ventricular volume decreases the radius, increases the thickness, and thereby reduces wall stress. This improves the myocardial oxygen supply/demand relationship, but may also revive the contractibility of otherwise normal but previously stressed myocardium. At the very least, the reduced stress on the heart 12 is relieved along with any potential for congestive heart failure.
A further advantage of this procedure relates to the incision 61 in the left ventricle 25 which also provides access to the mitral valve 34. Replacing this mitral value 34 through the left ventricle 25 is much simpler than the present intra-aortic replacement procedure. Coronary artery bypass grafts also can be more easily accommodated intraoperatively. As a result, all of these repairs can be undertaken with greater simplicity and reduced time. While blood cardioplegia may be advantageously used for revascularization and valvular procedures, it would appear that the restorative procedure is best accomplished with continuous profusion of the beating open heart for cardiac protection. Placement of patch 70 can be further enhanced by providing in the patch kit a plurality of sizing disks which can be individually held in proximity to the Fontan neck in order to determine appropriate patch size. Similar discs, triangular in shape may be used for the inferior restoration process. The disks might have a generally planar configuration, and of course, would vary in size. Each disk might have a centrally located handle extending from the planar disk for ease of use. The patch 72 could be removably mounted on a holder also including a disk, on which the patch is mounted, and an elongate handle extending from the disk to facilitate placement.
Figure 25 illustrates the inferior wall 44 after the heart 12 has been lifted from the patient's chest and the apex 37 rotated upwardly, generally about the base 35 of the heart 12. Thus, the base 35 which is normally above the apex 37 is illustrated below the apex 37 in Figure 25. Extending along the inferior wall 44 is the right coronary artery 120 which branches into the posterior descending artery 122. A blockage or occlusion 126 in the right coronary artery has resulted in ischemia producing a non- contractive region 128 which is illustrated by shading in
Figure 25. It is the purpose of this procedure relating to the inferior wall 44 of the heart to remove the non- contracting muscle of the region 128 from the ventricle and to restore the ventricular architecture as previously discussed.
As the incision is opened and the non-contracting regions 128 on either side are laid back, a line of separation 137 can be located between the non-contracting region 128 and contracting regions designated generally by the reference numeral 140. Basting sutures 142 are placed generally along this line of separation 137. These basting sutures 142 include a base suture 144 which extends between pledgets 146 and 148 along the base 37. Similarly, lateral basting sutures 148 and 151 can be placed to extend along the line of separation 137 between pledgits 153 and 155, and pledgets 157 and 160, respectively. In a preferred orientation, the lateral basting sutures 148 and 151 meet at a basting apex 162 and diverge to individually intersect the basting sutures 142 at the base 37. Thus, the basting sutures 142, 148 and 151 form a triangle along the line of separation 137. A patch 171 similar to the patch 72 previously discussed can be configured as illustrated generally in Figure 28. This patch 171 can be formed from a sheet 173 of biocompatible material and a continuous ring 175 such as the ring 87 previously discussed.
With the inferior patch, the conical form is unnecessary and a more planar or spherical configuration is preferable. This configuration helps form the desired triangular contour for the inferior wall 44. With the inferior patch 171, the sheet material 173 can be made of pericardium or Dacron or fascia. The preferred material will be similar to that of the apical patch previously discussed, but can be autogenous, bovine, or porcelain pericardium. The sheet material 173 will preferably, have a triangular shape as will the ring 175.
In a preferred embodiment, the shape of the ring 175 is geometrically similar to that of the sheet material 173.
Thus, when the ring 175 is disposed centrally of the sheet material 173, it defines a central area 177 and a circumferential rim 179 having a generally constant width around the central area 177. In preferred embodiments, the triangular central area 177 will have sizes such as 2x3x1 and 3x4x1. The width of the circumferential rim 179 will typically be in a range between 1 and 2 centimeters.
In a preferred method, the ring 175 is sewn to the neck formed by the basting sutures 142, 148 and 151 by sutures 180 extending interiorly through pledgets 182. Similar sutures 183 can be placed to extend entirely through the inferior wall 44 and an exterior pericardial strip 184 in proximity to the lateral basting sutures 151.
With the patch 171 thus positioned, as illustrated in Figure 30, the central area 177 partially defines the left ventricular chamber 25. However, the circumferential rim 179 remains exteriorly of the chamber 25 and extends along the inner surface 131 of the non-contracting region 128. In a further step of this procedure illustrated in Figure 30, the circumferential rim 179 can be fixed to the inner surface 131 by a running suture 186. In the manner previously discussed the circumferential rim 179 thus sutured to the non-contracting region 128 will inhibit any bleeding which may result from placement of the basting sutures 142, 148, 151 or the sutures 180 and 183 associated with placement of the patch 171.
It is believed that cardioplegia arrest may be deleterious to ventricular function in the open ventricle
10 because of nonuniform flow distribution. By avoiding this cardioplegia arrest and operating on a beating heart, aortic cross clamping as well as the use of inter-aortic balloons and ventricular assist devices can be avoided. Patch -,-- placement can be intraoperatively adjusted guided by echo or radio nucleotide data. Placement of the patch is further simplified by creation of the Fontan neck 78 or triangular neck 175, and use of interrupted felt or pericardial pledgeted sutures 105. The circumferential rim 93
20 associated with the patch 72 facilitates bleeding control without distortion of the patch 72. Finally, using a pants- over-vest closure of the excluded ventricle obliterates dead space and provides security against patch leaks and 25 resultant expansion between the site of closure of the ejecting ventricle with the patch, and where the excluded muscle is closed by the excluded ventricle.
If the patch has a conical or elliptical contour, the pants-over-vest closure is excluded, so that progressive
30 recovery of potentially hibernating muscle (previously akinetic) can occur so that the muscle itself forms the apex. The pants-over-vest closure may prevent this, and that is the reason for excluding it. Within these wide objectives and parameters, there will be variations on the structure of the patch and the methods of restoration. Although the non-circular configuration of the sheet material and ring are believed to be critical, the shape of the patch 72 may vary widely to provide the best anatomical fit with the natural shape of the ventricle 25.
The sheet material 81 may be composed of a variety of materials, both natural and artificial. These materials may be woven or nonwoven to achieve a desired structure for the sheet material 81. The ring 87 may similarly be formed from a variety of materials and provided with a variety of shapes in order to add structure to the patch 72 without interfering with the normal contractions of the heart 12. Variations of the steps of the associated restoration method might include mounting the patch with a convex surface facing the ventricular cavity, use of tissue adhesives are also contemplated for attaching sealing and otherwise fixing the patch 72 to the Fontan neck 78 or the triangle 175.
1. A ventricular patch adapted for placement relative to the inferior wall of the heart, comprising: a sheet of biocompatible material having a generally planar configuration and the shape of a first triangle; a continuous ring fixed to the sheet and having the shape of a second triangle geometrically similar to the first triangle; the ring defining a central region of the patch interiorly of the ring and a circumferential region of the patch exteriorly of the ring; and the circumferential region of the patch having a generally constant width around the central region of the patch.
3. The ventricular patch recited in claims 1 or 2 , wherein the first triangle has three sides with associated lengths in ratios of about 2 to 3 to 1.
4. The ventricular patch recited in claims 1, 2, or 3 , wherein the first triangle has three sides with associated lengths in ratios of about 3 to 4 to 1.
5. The ventricular patch recited in claims 1, 2, 3, or , wherein the bio-compatable material includes at least one of pericardium, Dacron and fascia.
6. The ventricular patch recited in claims 1, 2, 3, 4, or 5, wherein the pericardium is one of autologous, bovine, and porcein.
7. A method for restoring the ventricular architecture of a heart having an anterior wall and an inferior wall, comprising the steps of : creating an incision in the inferior wall of the heart to expose an inner surface of the ventricle of the heart; forming a suture line around the inner surface of the inferior wall; providing a ventricular patch; and sewing the ventricular patch to the inner surface of the inferior wall along the suture line to restore the ventricular architecture of the heart.
8. The method recited in claim 7, wherein the providing step includes the step of forming the ventricular patch to include a sheet of biocompatible material and a continuous ring fixed to the sheet .
9. The method recited in claims 7 or 8 , wherein the creating step includes the steps of creating the incision in a non-contracting region of the inferior wall; opening the incision to expose an inner surface of the heart, the contracting region being separated from the non- contracting region by a line of separation.
10. The method recited in claim 9, wherein the forming step includes the step of forming the suture line generally along the line of separation.
11. The method recited in claims 8, 9, or 10, wherein the forming step includes the step of : attaching the ring to the biocompatible material so that the ring defines a central area of the material inwardly of the ring and an outer rim of the material outwardly of the ring.
12. The method recited in claim 11, wherein the attaching step includes the step of: sewing the continuous ring to the inner surface of the ventricle so that the central area of the material defines a portion of the ventricle of the heart; and sewing the outer rim to the inner surface of the ventricle outwardly of the ventricle of the heart.
13. The method recited in claims 9, 10, 11, or 12 wherein the opening step includes the step of spreading the incision to create a triangular opening extending into the ventricle of the heart .
14. The method recited in claims 8, 9, 10, 11, 12, or 13, wherein the forming step includes the step of forming the biocompatible material and the continuous ring in the shape of a triangle.
PCT/US2000/001596 1998-05-01 2000-01-21 Anterior and inferior segment cardiac restoration apparatus and method WO2000042919A1 (en)
US09/235,664 1999-01-22
WO2000042919A1 true WO2000042919A1 (en) 2000-07-27
PCT/US2000/001596 WO2000042919A1 (en) 1998-05-01 2000-01-21 Anterior and inferior segment cardiac restoration apparatus and method
Ref document number: 2000909954