Thromboembolism in patients with pericardial valves in the absence of chronic anticoagulation: 12 years' experience

Fine structure of glycosaminoglycans from fresh and decellularized porcine cardiac valves and pericardium

Cardiac valves are dynamic structures, exhibiting a highly specialized architecture consisting of cells and extracellular matrix with a relevant proteoglycan and glycosaminoglycan content, collagen and elastic fibers. Biological valve substitutes are obtained from xenogenic cardiac and pericardial tissues. To overcome the limits of such non viable substitutes, tissue engineering approaches emerged to create cell repopulated decellularized scaffolds. This study was performed to determine the glycosaminoglycans content, distribution, and disaccharides composition in porcine aortic and pulmonary valves and in pericardium before and after a detergent-based decellularization procedure. The fine structural characteristics of galactosaminoglycans chondroitin sulfate and dermatan sulfate were examined by FACE. Furthermore, the mechanical properties of decellularized pericardium and its propensity to be repopulated by in vitro seeded fibroblasts were investigated. Results show that galactosaminoglycans and hyaluronan are differently distributed between pericardium and valves and within heart valves themselves before and after decellularization. The distribution of glycosaminoglycans is also dependent from the vascular district and topographic localization. The decellularization protocol adopted resulted in a relevant but not selective depletion of galactosaminoglycans. As a whole, data suggest that both decellularized porcine heart valves and bovine pericardium represent promising materials bearing the potential for future development of tissue engineered heart valve scaffolds.

Pericarbon pericardial bioprosthesis: an experience based on the lessons of the past

BACKGROUND

The Pericarbon pericardial bioprosthesis, at the time of its creation, showed a breakthrough in terms of low calcification deposit rate, absence of valvular tears, and durability. The purpose of this study was to evaluate results after 10 years.

METHODS

From September 1988 to December 1997, 277 patients received a total of 287 Pericarbon pericardial valves. There were 224 (80.8%) isolated aortic valve replacements (AVR), 39 isolated mitral valve replacements (MVR), 1 tricuspid valve replacement, 3 pulmonary valve replacements, and 10 aortic and mitral valve replacements. The total cumulative follow-up was 1,221.42 patient-years (mean 4.9+/-2.6 years).

RESULTS

Overall hospital mortality was 10.1%. The overall patient survival at 10.8 years was 55.8%+/-4.2%, for AVR it was 60.0%+/-4.5%, and for MVR it was 46.5%+/-11.9%. The freedom from valve-related death for the overall population at 10.8 years was 98.0%+/-1.0%, for AVR 97.6%+/-1.1%, and for MVR 100%. The overall freedom from structural valve deterioration was 96.6%+/-2.4%, for AVR 96.1%+/-2.7%, and for MVR 100%. The overall freedom from embolic events was 96.0%+/-1.5%, for AVR 96.0%+/-1.6%, and for MVR 100%. The overall freedom from reoperation was 88.1%+/-3.8%, for AVR 89.9%+/-4.2%, and for MVR 80.6%+/-7.3%.

CONCLUSIONS

These results show that over a period of up to 10 years, the Pericarbon pericardial bioprosthesis is an excellent and safe valve substitute. Developing a detoxification process aimed at improving the biological behavior of the glutaraldehyde-tanned valve may increase those advantages.

Mitroflow pericardial bioprosthesis: clinical performance to ten years

The Mitroflow pericardial bioprothesis, a second generation pericardial prosthesis, has clinical performance assessment to 10 years. This bioprosthesis was used in 445 operations in 445 patients between 1982 and 1992 inclusive (mean age, 59.1 years; age range, 19 to 94 years). There were 253 aortic valve replacements (AVR), 155 mitral valve replacements (MVR), 31 multiple valve replacements (MR), and 6 tricuspid valve replacements. Concomitant procedures were performed in 40 patients (14.2%). The age group distributions (years) were less than or equal to 35 years, 28 patients; 36 to 50 years, 79; 51 to 64 years, 167; 65 to 69 years, 70; and 70 years or more, 101 patients. The total follow-up was 1,524 patient-years (mean, 5.4 years), 96% complete. The early mortality was 6.3%/patient-year (28 patients) and the late mortality was 4.1%/patient-year (96 patients). Concomitant procedures did not influence either early or late mortality (p = not significant [NS]). The overall patient survival at 10 years was 58% +/- 5% (p = NS by valve position). The overall freedom from structural valve deterioration (SVD) at 8 years was 69% +/- 3% and at 10 years, 45% +/- 7%; and at 8 years AVR 80% +/- 4%, MVR 58% +/- 6%, and MR 38% +/- 11% (p < 0.05, AVR > MVR > MR). The freedom from thromboembolism (TE) was 87% +/- 2%, overall at 10 years, and was not different by valve position (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler echocardiographic comparison of small (19 mm) bileaflet and pericardial heart valve prostheses in aortic position

The resting haemodynamics of five types of small (19 mm) aortic valve prosthesis (2 bileaflet, 3 pericardial) were evaluated with Doppler echocardiography in 43 patients. Two received St Jude Medical and six CarboMedics bileaflet valves and 35 were given bioprostheses--16 Ionescu-Shiley, four Mitroflow and 15 Labcor-Santiago. No significant differences in peak or mean transvalvular pressure drop or in effective valve area were found between the bileaflet and the pericardial valves or among the three types of bioprosthesis. All but one of the bileaflet prostheses showed a characteristic regurgitation pattern, with two lateral and one central jet, and 16 (46%) of the bioprostheses showed central regurgitation, but in no case were these jets haemodynamically significant. Thus the 19 mm bileaflet and the studied pericardial prostheses all have satisfactory resting haemodynamics, and all are suitable for implanting in small aortic roots.

Mitral valve Carpentier-Edwards bioprosthetic replacement, thromboembolism, and anticoagulants

Patients undergoing mitral valve replacement (MVR) using a bioprosthesis are frequently placed on long-term anticoagulant treatment, and thereby lose the main advantage conferred by the bioprosthesis. To assess predictive factors of the need for long-term anticoagulant treatment, 100 consecutive patients surviving bioprosthetic MVR between 1977 and 1987 were followed up. The estimated thromboembolism-free survival was 88.9% +/- 3.6% after 6 years of follow-up. Preoperative risk factors for thromboembolism were supraventricular arrhythmia (p = 0.013) and a history of thromboembolism (p = 0.039). Among the preoperative and postoperative factors, only postoperative rhythm significantly influenced (p = 0.007) the thromboembolism-free survival, as determined by Cox regression analysis. Permanent anticoagulant treatment was instituted in 39 patients. Preoperative and peroperative risk factors associated with the need for long-term anticoagulant treatment, as evidenced by Fisher linear discriminant analysis, were supraventricular arrhythmia (p < 0.001), septal myotomy (p = 0.013), and predominant mitral stenosis (p = 0.013). Thus, in those patients with predominant mitral stenosis and supraventricular arrhythmia preoperatively, the subsequent need for permanent postoperative anticoagulant treatment is high, and the implantation of a mechanical valve is therefore recommended, providing there are no strict contraindications to anticoagulant treatment.