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Twenty-three lonescu-Shiley standard bovine pericardial bioprostheses (15 aortic, seven mitral, and one tricuspid) removed at surgery from 21 adults, 28 to 75 years old (mean 55 at reoperation), were examined after functioning for as long as 84 months (mean 26 BIOPROSTHESES fabricated from glutaraldehydepretreated porcine aortic valves or bovine pericardium are commonly used to replace diseased human cardiac valves. Primary tissue degeneration due to intrinsic cuspal calcification is the most frequent cause of failure of porcine aortic valve bioprostheses. [1][2][3][4][5] Commercially prepared glutaraldehyde-preserved bioprosthetic heart valves fabricated from bovine pericardium, introduced into general clinical practice in 1976, are now widely used. Actuarially determined freedom from primary tissue failure of the popular Ionescu-Shiley standard pericardial valve has been variably reported to be 60% at 6 years,6 80% to 95% at 6 years,7-and 90% at 11 years.

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Accumulated evidence indicates that fresh aortic valve homografts function longer than preserved grafts. Thus it becomes important to assess the viability of fresh homografts on a quantitative basis. Recently, we have used autoradiography in addition to tissue culture to determine the viability of fresh aortic and pulmonary valve homografts. The uptake of thymidine was gradually reduced to 50% after 18 days of preservation in a balanced salt solution with antibiotics and the uptake was reduced to 21 % in 63 days. We think that a nutrient medium is necessary if longer viability is to be obtained.

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Atrial natriuretic peptide (ANP) is a newly discovered peptide hormone present mainly in the atria. We investigated the occurrence and distribution of ANP immunoreactivity in the myocardiocytes of the ventricles of spontaneously hypertensive rats by use of immunocytochemistry at both light and electron microscopic level. ANP immunoreactivity was found in the specific granules in the cytoplasm of the cardiocytes in the subendocardium and the myocardium of the ventricles, as well as in the atria. The specific granules found in the ventricles of hypertensive rats were similar in size, shape, and ANP immunoreactive content to those in the atria. The abundance of ANP immunoreactivity in the GU, GONZALEZ-LAVIN through graded alcohols and xylene and embedded in paraffin. Eight-sm consecutive sections were cut and mounted on poly-L-lysine-coated glass slides (17). After dc-waxing, two sections from each region were stained with hematoxylin and eosin (H&E) to assess the general morphology. Four slides from each region were immunostained with antibodies to alpha-ANP.

Of 1,193 consecutive pediatric (less than 18 years) patients undergoing intracardiac repair from 1975 to 1984, 38 (3.2%) developed surgically induced complete heart block and were treated by permanent pacemaker implantation. Anomalies included complete atrioventricular septal defect = 9 (24%), simple ventricular septal defect = 9 (24%), atrioventricular discordant connection = 8 (212), tetralogy of Fallot = 7 (182), and other complex anomalies = 5 (13%). There were no hospital deaths. follow-up was 100% complete. There were six late deaths = 16%. Actuarial survival was 79 + 9% at 10 years. None of the late deaths were related to disturbance of cardiac rhythm or pacemaker system failure. Twelve patients (32%), required 27 reoperations for various types of pacemaker system failure. Indications for reoperation included: lead failure (44%). Pulse generator failure (44%), and wound sepsis (12%). Actuarial freedom from any pacemaker related reoperation was 50 + 16% at 48 months and 25 + 15% at 96 months. Only first reoperation was found to be an incremental risk factor for subsequent reoperation (p = 0.03). Surgical heart block has been neutralized as a risk factor for hospital death after repair of congenital cardiac defects. The risk of the development of surgical heart block now approaches zero, as indicated by a decreased incidence (1 of 401 = 0.25%) in our institution from 1985 to 1987, as compared to the era 1975 to 1984 (p = 0.001).