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A precaution when using the St. Jude Medical prosthesis in the aortic valve position
BRIEF REPORTS A PrecautionWhen Usingthe St. Jude Medical Prosthesis in the AorlticValve Position ELIZABETH M. ROSS, MD, WILLIAM C. ROBERTS, MD
The St. Jude Medical (SJM) prosthesis is increasingly being used for cardiac valve replacement. In 1980, the manufacturer supplied 9,000 SJM prostheses to surgeons, and in 1983 this number had increased to 18,500. From 1977 through 1983,45,000 SJM prostheses were supplied to surgeons. The SJM prosthesis appears to be durable,lp2 its orifice area is larger for its size than any other mechanical prosthesis or for any tissue valve mounted on a frame,3--s its low profile prevents interference to leaflet movement by adjacent tissues, and it appears to be less destructive to blood elements than any other mechanical prosthesis.g Its major disadvantage is its delicate hinge mechanism, which could be interfered with more easily than other mechanical prostheses by thrombus or suture or a calcific deposit.1°-12 Additionalky, like all mechanical prosthetic valves, anticoagulants are required.13 The SJM prosthesis is a bit more expensive than other available mechanical prostheses or bioprostheses. Recently, we examined the hearts of 2 patients who died early after replacement of the aortic valve with a SJM prosthesis. In each patient, it appeared that movement of 1 of the 2 SJM prosthetic leaflets was interfered with by underlying severe hypertrophy and leftward positioning of the ventricular septum in 1 patient (who died 6 days after aortic valve replacement) and by underlying severely thickened anterior mitral leaflet in the other patient (who could not be separated from cardiopulmonary bypass).
To better understand the real or potential interference to movement of I. or both leaflets of a SJM prosthesis in the aortic valve position, an appreciation of the normal opening and closing of these leaflets of the SJM prosthesis is essential. The 2 leaflets are suspended on parallel pivots, which allows each leaflet to open to 85” from the closed position (Fig. 1 and 2). This allows an orifice area of 1.6 to 5.1 cm2 for valve sizes 18 to 33. The valve in the open position has 3 approximately equalsized orifices. The leaflets are contained within a pyrolyte ring, and this results in a low-profile configuration. In the closed position, the leaflets fall entirely within the orifice ring and the leaflets meet the valve housing at a 30’ to 35” angle. The seamless sewing cuff ismade of double velour Dacron and is attached to the pyrolyte valve ring such that the leaflets do not contact the cuff. In the aortic valve position, the “v” formed by
From the Pathology Branch, National Heart, Lung, and Blood Institute, National InstiMes of Health, Bethesda, Maryland. Manuscript received and accepted March 21, 198’4.
the 2 leaflets of the SJM prosthesis when the valve is closed points “upstream,” i.e., toward the left ventricle. The key element to proper opening of the SJM valve in the aortic valve position during ventricular systole is the application of a greater pressure to the leaflet peripheral to the pivot compared to that applied central to the pivot. If either the ventricular septum or anterior mitral leaflet prevents adequate pressure from contacting the leaflet peripheral to the pivot, leaflet opening could be incomplete or prevented (Fig. 3). The most likely circumstance in which the ventricular septum could prevent the application of adequate pressure’s being applied to the undersurface of a SJM leaflet in the aortic valve position is in the older patient with aortic valve stenosis. In the normal aging process, the ascending aorta moves toward the right (presumably because the elasticity of the aortic wall diminishes and blood ejected from the left ventricle contacts the right wall of the aorta) and the left ventricular cavity gets smaller (presumably because the cardiac output and stroke volume decrease). The combination of the rightward movement of the aorta and the decreasing size of the left ventricular cavity results in the most cephalad portion of the muscular ventricular septum being located directly beneath the aortic valve, rather than to the right of it as in younger persons. When this normal occurrence of aging is complicated by aortic valve stenosis, the movement of the ascending aorta to the right is exaggerated (presumably because of the poststenotic jet effect) and the severe hypertrophy of the left ventricular walls allows even more of the ventricular septum to be located directly beneath the aortic valve (Fig. 4). The result, as we believe occurred in 1 of our 2 patients mentioned earlier, may be incomplete or total lack of opening of 1 of the SJM prosthetic leaflets as a result of inadequate application of left ventricular systolic pressure’s being applied to the ventricular as-
ew om de
Anterior-Posterior Orientation
Right-Left Orientation
FIGURE 1. Two orientations of a St. Jude prosthesis in the aortic valve position during ventricular systole.
232
BRIEF REPORTS
FIGURE 2. Views of the St. Jude’s Medical prosthesis from below (left) and from the side (right). Radiographs are shown in the upper panel.
Aorta
FIGURE 3. Diagram showing a St. Jude Medical prosthesis in the aortic valve position and how the 2 leaflets normally open and close (upper panel). Lower left, diagam showing how a thickened ventricular septum (VS) could prevent opening of 1 of the 2 prosthetic disc. Lower right, diagram showing how a very thidtened anterior mitral leaflet (AM) may prevent opening 1 of the 2 prosthetic leaflets.
FIGURE 4. Severely stenotic aortic valve from above (top) and longitudinal view of heart (bottom) showing a very thick ventricular septum (VS) with its crest pointing toward the left atrium (LA) and the aottic valve (AV) located almost to the right of the VS. Blood exiting the left ventricle (LV) must take a very sigmoid route. LM = left main coronary artery; MVA Ca++ = mitral valve anular calcium; R = right coronary artery; RV = right ventricular cavity.
July 1, 1984
pect of the leaflets. Awareness of the hazard of a thick ventricular septum dir’ectly beneath an excised aortic valve should caution the operator that a prosthesis (or bioprosthesis) other than a SJM might be preferred or that the orientation of the SJM prosthesis should be such that the septum could not prevent one of the SJM leaflets from receiving properly applied left ventricular systolic pressure. The orientation judgment with a SJM prosthesis must be made before insertion of the first prosthetic securing suture because rotation of the pyrolyte ring is not advised after the prosthesis has been sewn to the aortic wall. References 1. Nlcoloff DM, Emery RW, Arom KV, Northrup WF, Jorgensen CR, Wan9 Y, Mdsay WG. Clinical and hemodynamic results with the St. Jude Medical cardiac valve prosthesis. J lhorac Cardiovasc Surg 1981;82:674-683. 2. Horstkolle D, Korfer R, SelplleL, Blrcks W, LoogenF. Late complications in patients with Bjork-Shiley and St. Jude Medical heart valve replacement. Circulation 1983;68:suppl ll:ll-175-11-184.
Cardiac MorphologicFindingsLate After Partial Left Ventricular EndomyocalrdialResectionfor RecurrentVentricularTachycardia MARC A. SILVER, MD ANDREW I. COHEN, MD NEVIN M. KATZ, MD ROSS D. FLETCHER, MD VICTOR J. FERRANS, MD, PhD WILLIAM C. ROBERTS, MD
Operative excision of portions of left ventricular (LV) endocardium and underlying myocardium often abolishes chronic, recurrent, sustained ventricular tachycardia (VT) in patients with healed myocardial infarction (MI) with or without associated LV aneurysm.l Fenoglio et al2 described morphologic features of operatively excised LV subendocardial regions in 23 patients with recurrent VT. No studies have described early or late cardiac findings at necropsy in patients who have had focal endomyocardial LV resection for recurrent VT. Such is the purpose of this report. M.K., a 51-year-old man, had electrocardiographic evidence of a posterior wall acute MI at age 49 years. Because of subsequent angina pectoris and episodes of dizziness, he was hospitalized 10 weeks after the initial chest pain. A 24-hour Holter monitor recording at that time disclosed nonsustained (5 beats) VT. Sustained VT was inducible by 3 or 4 premature stimuli with a pacing catheter in the right
From the Pathology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; the Electrophysiology Laboratory and Deparb~nt oi Cardiilogy, District of Colurnbii Veterans Administration Medical Center, Washington, D.C.; and the Department of Surgery, Georgetown University, Washington, D.C. Manuscript received and accepted March 22, 1984.
THE AMERICAN JOURNAL OF CARDIOLOGY
Volume 54
233
3. Emery RW, NicoloffGM. St. Jude Medical cardiac valve prosthesis in vitro studies. J Thorac Cardiovasc Surg 1979;78:269-276. 4. Wortham DC, TrI TB, Bowen TE. Hemodynamic evaluation of the St. Jude Medical valve prosthesis in the small aortic anulus. J Thorac Cardiovasc Surg 1981;81:815-820. 5. Gill CC, King HC, Lytle BW, Cosgrove DM, Gelding LA, Loop FD. Early clinical evaluation after aortic valve replacement with the St. Jude Medical valve in patients with a small aortic root. Circulation 1982;66:147-149. 6. Yoganathan AP, Chaux A, Gray RJ, DeRoberlis M, Matlofl JM. Flow characteristics of the St. Jude prosthetic valve: An in vitro and in vivo study. Artificial Organs 1982;6:289-294. 7. Horstkotle D. Ha&en K. Selpei L. Korfer R. Budde T, Blrcks W. Looeen F. Central he&dynamics at iest and during exercise arter mitral halve-realacement with different orostheses. Circulation 1983:68:181-168. AP, Chaux A, Gray RJ, Woo YR, DeRobehls M, Wllllams FP, 6. &&atham Malloff JM. Bileaflet tilting disc and porcine aortic valve substitutes: In vivo hydrodynamic characteristics. J Am Coll Cardiol 1984;3:321-327. 9. Lillehel CW. Worldwide experience with the St. Jude valve prosthesis: clinical and hemodynamic results. Contemp Surg 1982;20:87. 10. Nuner L, lgleslas A, Sotlllo J. Entrapment of leaflet of St. Jude Medical cardiac valve prosthesis by miniscule thrombus: report of two cases. Ann Thora? Surg 1979;29:567-569. 11. 1 Commerford PJ, Lloyd EA, DeNobrega JA. Thrombosis of St. Jude Medical cardiac valve in the mitral position. Chest 1981;80:326-327. 12. Zlemer G, Luhmer I, Delerl H, Borsf HG. Malfunction of a St. Jude Medical heart valve in mitral position. Ann Thorac Surg 1981;33:391-395. 13. Chaux A, Gray RJ, Matloff JM, Feldman H, Sustalta H. An application of the new St. Jude valvular prosthesis. J Thorac Cardiovasc Surg 1981;81: 202-211.
ventricular cavity before and after administration of multiple antiarrhythmic drugs. LVangiography disclosed inferior wall akinesia without LVaneurysm. The LVejection fraction was 37% and the cardiac index was 2.6 liters/minfm2. By selective angiography, the luminal diameter of the left anterior descending coronary artery was decreased 51 to 75%) that of the left circumflex 100% , and that of the right 100%. The LVpressure was 11Ofll mm Hg and the pulmonary artery wedge mean pressure was 10 mm Hg. Endocardial pace mapping disclosed that the origin of the inducible VT was in the ventricular septum and in the mid- and basal lateral LV free wall. At operation, the VT focus was located between the LV papillary muscles. The endocardium of this region was slightly thickened, and it and the underlying subendocardium were resected, Also, a portion of ventricular septum, the endocardium of which was only mildly thickened, also was excised. After closing the LV incision, saphenous vein conduits were placed between the aorta and left anterior descending, 2 obtuse marginal branches and the posterior descending coronary arteries. The patient’s initial recovery was uneventful. Postoperative electrocardiogram revealed sinus rhythm and a new left bundle branch block. Soon after discharge, however, abdominal pain developed at the site of the subcutaneous pacemaker leads. The leads eventually eroded through the skin, causing a subcutaneous infection and, later, purulent mediastinitis. Despite antibiotics and sternotomy debridement, the patient died of sepsis 19 months after operation. VT never recurred postoperatively. At necropsy, the heart weighed 66Og. The saphenous vein bypass conduits were patent. The major epicardial coronary arteries were severely narrowed by atherosclerotic plaques. A small transmural scar was present in the LVposterior wall. Portions of the LV endocardium, including the ventricular septum and the area between and including both papillary muscles were white, smooth and thickened by fibrous tissue (Fig. 1,2 and 3) and the underlying myocardium in these areas was free of grossly visible scar. On electron microscopy, the white endocardial fibrous tissue consisted of collagen fibrils and elastic fibers, both of which were morphologically normal (Fig. 4). The ultrastructural appearance of this tissue resembled that described in the secondary or acquired form of endocardial fibroelastosis.3
The St. Jude Medical (SJM) prosthesis is increasingly being used for cardiac valve replacement. In 1980, the manufacturer supplied 9,000 SJM prostheses to surgeons, and in 1983 this number had increased to 18,500. From 1977 through 1983,45,000 SJM prostheses were supplied to surgeons. The SJM prosthesis appears to be durable,lp2 its orifice area is larger for its size than any other mechanical prosthesis or for any tissue valve mounted on a frame,3--s its low profile prevents interference to leaflet movement by adjacent tissues, and it appears to be less destructive to blood elements than any other mechanical prosthesis.g Its major disadvantage is its delicate hinge mechanism, which could be interfered with more easily than other mechanical prostheses by thrombus or suture or a calcific deposit.1°-12 Additionalky, like all mechanical prosthetic valves, anticoagulants are required.13 The SJM prosthesis is a bit more expensive than other available mechanical prostheses or bioprostheses. Recently, we examined the hearts of 2 patients who died early after replacement of the aortic valve with a SJM prosthesis. In each patient, it appeared that movement of 1 of the 2 SJM prosthetic leaflets was interfered with by underlying severe hypertrophy and leftward positioning of the ventricular septum in 1 patient (who died 6 days after aortic valve replacement) and by underlying severely thickened anterior mitral leaflet in the other patient (who could not be separated from cardiopulmonary bypass).
To better understand the real or potential interference to movement of I. or both leaflets of a SJM prosthesis in the aortic valve position, an appreciation of the normal opening and closing of these leaflets of the SJM prosthesis is essential. The 2 leaflets are suspended on parallel pivots, which allows each leaflet to open to 85” from the closed position (Fig. 1 and 2). This allows an orifice area of 1.6 to 5.1 cm2 for valve sizes 18 to 33. The valve in the open position has 3 approximately equalsized orifices. The leaflets are contained within a pyrolyte ring, and this results in a low-profile configuration. In the closed position, the leaflets fall entirely within the orifice ring and the leaflets meet the valve housing at a 30’ to 35” angle. The seamless sewing cuff ismade of double velour Dacron and is attached to the pyrolyte valve ring such that the leaflets do not contact the cuff. In the aortic valve position, the “v” formed by
From the Pathology Branch, National Heart, Lung, and Blood Institute, National InstiMes of Health, Bethesda, Maryland. Manuscript received and accepted March 21, 198’4.
the 2 leaflets of the SJM prosthesis when the valve is closed points “upstream,” i.e., toward the left ventricle. The key element to proper opening of the SJM valve in the aortic valve position during ventricular systole is the application of a greater pressure to the leaflet peripheral to the pivot compared to that applied central to the pivot. If either the ventricular septum or anterior mitral leaflet prevents adequate pressure from contacting the leaflet peripheral to the pivot, leaflet opening could be incomplete or prevented (Fig. 3). The most likely circumstance in which the ventricular septum could prevent the application of adequate pressure’s being applied to the undersurface of a SJM leaflet in the aortic valve position is in the older patient with aortic valve stenosis. In the normal aging process, the ascending aorta moves toward the right (presumably because the elasticity of the aortic wall diminishes and blood ejected from the left ventricle contacts the right wall of the aorta) and the left ventricular cavity gets smaller (presumably because the cardiac output and stroke volume decrease). The combination of the rightward movement of the aorta and the decreasing size of the left ventricular cavity results in the most cephalad portion of the muscular ventricular septum being located directly beneath the aortic valve, rather than to the right of it as in younger persons. When this normal occurrence of aging is complicated by aortic valve stenosis, the movement of the ascending aorta to the right is exaggerated (presumably because of the poststenotic jet effect) and the severe hypertrophy of the left ventricular walls allows even more of the ventricular septum to be located directly beneath the aortic valve (Fig. 4). The result, as we believe occurred in 1 of our 2 patients mentioned earlier, may be incomplete or total lack of opening of 1 of the SJM prosthetic leaflets as a result of inadequate application of left ventricular systolic pressure’s being applied to the ventricular as-
ew om de
Anterior-Posterior Orientation
Right-Left Orientation
FIGURE 1. Two orientations of a St. Jude prosthesis in the aortic valve position during ventricular systole.
232
BRIEF REPORTS
FIGURE 2. Views of the St. Jude’s Medical prosthesis from below (left) and from the side (right). Radiographs are shown in the upper panel.
Aorta
FIGURE 3. Diagram showing a St. Jude Medical prosthesis in the aortic valve position and how the 2 leaflets normally open and close (upper panel). Lower left, diagam showing how a thickened ventricular septum (VS) could prevent opening of 1 of the 2 prosthetic disc. Lower right, diagram showing how a very thidtened anterior mitral leaflet (AM) may prevent opening 1 of the 2 prosthetic leaflets.
FIGURE 4. Severely stenotic aortic valve from above (top) and longitudinal view of heart (bottom) showing a very thick ventricular septum (VS) with its crest pointing toward the left atrium (LA) and the aottic valve (AV) located almost to the right of the VS. Blood exiting the left ventricle (LV) must take a very sigmoid route. LM = left main coronary artery; MVA Ca++ = mitral valve anular calcium; R = right coronary artery; RV = right ventricular cavity.
July 1, 1984
pect of the leaflets. Awareness of the hazard of a thick ventricular septum dir’ectly beneath an excised aortic valve should caution the operator that a prosthesis (or bioprosthesis) other than a SJM might be preferred or that the orientation of the SJM prosthesis should be such that the septum could not prevent one of the SJM leaflets from receiving properly applied left ventricular systolic pressure. The orientation judgment with a SJM prosthesis must be made before insertion of the first prosthetic securing suture because rotation of the pyrolyte ring is not advised after the prosthesis has been sewn to the aortic wall. References 1. Nlcoloff DM, Emery RW, Arom KV, Northrup WF, Jorgensen CR, Wan9 Y, Mdsay WG. Clinical and hemodynamic results with the St. Jude Medical cardiac valve prosthesis. J lhorac Cardiovasc Surg 1981;82:674-683. 2. Horstkolle D, Korfer R, SelplleL, Blrcks W, LoogenF. Late complications in patients with Bjork-Shiley and St. Jude Medical heart valve replacement. Circulation 1983;68:suppl ll:ll-175-11-184.
Cardiac MorphologicFindingsLate After Partial Left Ventricular EndomyocalrdialResectionfor RecurrentVentricularTachycardia MARC A. SILVER, MD ANDREW I. COHEN, MD NEVIN M. KATZ, MD ROSS D. FLETCHER, MD VICTOR J. FERRANS, MD, PhD WILLIAM C. ROBERTS, MD
Operative excision of portions of left ventricular (LV) endocardium and underlying myocardium often abolishes chronic, recurrent, sustained ventricular tachycardia (VT) in patients with healed myocardial infarction (MI) with or without associated LV aneurysm.l Fenoglio et al2 described morphologic features of operatively excised LV subendocardial regions in 23 patients with recurrent VT. No studies have described early or late cardiac findings at necropsy in patients who have had focal endomyocardial LV resection for recurrent VT. Such is the purpose of this report. M.K., a 51-year-old man, had electrocardiographic evidence of a posterior wall acute MI at age 49 years. Because of subsequent angina pectoris and episodes of dizziness, he was hospitalized 10 weeks after the initial chest pain. A 24-hour Holter monitor recording at that time disclosed nonsustained (5 beats) VT. Sustained VT was inducible by 3 or 4 premature stimuli with a pacing catheter in the right
From the Pathology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland; the Electrophysiology Laboratory and Deparb~nt oi Cardiilogy, District of Colurnbii Veterans Administration Medical Center, Washington, D.C.; and the Department of Surgery, Georgetown University, Washington, D.C. Manuscript received and accepted March 22, 1984.
THE AMERICAN JOURNAL OF CARDIOLOGY
Volume 54
233
3. Emery RW, NicoloffGM. St. Jude Medical cardiac valve prosthesis in vitro studies. J Thorac Cardiovasc Surg 1979;78:269-276. 4. Wortham DC, TrI TB, Bowen TE. Hemodynamic evaluation of the St. Jude Medical valve prosthesis in the small aortic anulus. J Thorac Cardiovasc Surg 1981;81:815-820. 5. Gill CC, King HC, Lytle BW, Cosgrove DM, Gelding LA, Loop FD. Early clinical evaluation after aortic valve replacement with the St. Jude Medical valve in patients with a small aortic root. Circulation 1982;66:147-149. 6. Yoganathan AP, Chaux A, Gray RJ, DeRoberlis M, Matlofl JM. Flow characteristics of the St. Jude prosthetic valve: An in vitro and in vivo study. Artificial Organs 1982;6:289-294. 7. Horstkotle D. Ha&en K. Selpei L. Korfer R. Budde T, Blrcks W. Looeen F. Central he&dynamics at iest and during exercise arter mitral halve-realacement with different orostheses. Circulation 1983:68:181-168. AP, Chaux A, Gray RJ, Woo YR, DeRobehls M, Wllllams FP, 6. &&atham Malloff JM. Bileaflet tilting disc and porcine aortic valve substitutes: In vivo hydrodynamic characteristics. J Am Coll Cardiol 1984;3:321-327. 9. Lillehel CW. Worldwide experience with the St. Jude valve prosthesis: clinical and hemodynamic results. Contemp Surg 1982;20:87. 10. Nuner L, lgleslas A, Sotlllo J. Entrapment of leaflet of St. Jude Medical cardiac valve prosthesis by miniscule thrombus: report of two cases. Ann Thora? Surg 1979;29:567-569. 11. 1 Commerford PJ, Lloyd EA, DeNobrega JA. Thrombosis of St. Jude Medical cardiac valve in the mitral position. Chest 1981;80:326-327. 12. Zlemer G, Luhmer I, Delerl H, Borsf HG. Malfunction of a St. Jude Medical heart valve in mitral position. Ann Thorac Surg 1981;33:391-395. 13. Chaux A, Gray RJ, Matloff JM, Feldman H, Sustalta H. An application of the new St. Jude valvular prosthesis. J Thorac Cardiovasc Surg 1981;81: 202-211.
ventricular cavity before and after administration of multiple antiarrhythmic drugs. LVangiography disclosed inferior wall akinesia without LVaneurysm. The LVejection fraction was 37% and the cardiac index was 2.6 liters/minfm2. By selective angiography, the luminal diameter of the left anterior descending coronary artery was decreased 51 to 75%) that of the left circumflex 100% , and that of the right 100%. The LVpressure was 11Ofll mm Hg and the pulmonary artery wedge mean pressure was 10 mm Hg. Endocardial pace mapping disclosed that the origin of the inducible VT was in the ventricular septum and in the mid- and basal lateral LV free wall. At operation, the VT focus was located between the LV papillary muscles. The endocardium of this region was slightly thickened, and it and the underlying subendocardium were resected, Also, a portion of ventricular septum, the endocardium of which was only mildly thickened, also was excised. After closing the LV incision, saphenous vein conduits were placed between the aorta and left anterior descending, 2 obtuse marginal branches and the posterior descending coronary arteries. The patient’s initial recovery was uneventful. Postoperative electrocardiogram revealed sinus rhythm and a new left bundle branch block. Soon after discharge, however, abdominal pain developed at the site of the subcutaneous pacemaker leads. The leads eventually eroded through the skin, causing a subcutaneous infection and, later, purulent mediastinitis. Despite antibiotics and sternotomy debridement, the patient died of sepsis 19 months after operation. VT never recurred postoperatively. At necropsy, the heart weighed 66Og. The saphenous vein bypass conduits were patent. The major epicardial coronary arteries were severely narrowed by atherosclerotic plaques. A small transmural scar was present in the LVposterior wall. Portions of the LV endocardium, including the ventricular septum and the area between and including both papillary muscles were white, smooth and thickened by fibrous tissue (Fig. 1,2 and 3) and the underlying myocardium in these areas was free of grossly visible scar. On electron microscopy, the white endocardial fibrous tissue consisted of collagen fibrils and elastic fibers, both of which were morphologically normal (Fig. 4). The ultrastructural appearance of this tissue resembled that described in the secondary or acquired form of endocardial fibroelastosis.3