The durability of the xenograft cardiac substitute vales is of a great concern on the clinical grounds. Four groups of total and consecutive patients to the end of study operated on between 1976 and 1984 were Group ISM, 291 patients of MVR, ISA,
65
patients of AVR, and ISMA, 107 patients of MVR+AVR with the standard Ionescu-Shiley bovine pericardial valve, and H, 163 patients of valve replacement with the Hancock porcine aortic valve.
Operative mortality was 5.2%(ISM), 10.8(ISA), 7.5(ISMA and 6.1%(H). Early survivors were followed up for a total of 1148.3 patient-years(pt-yrs)(ISM), 271.2 pt-yrs(ISA), 488.1 pt-yrs(ISMA) and 822.9 pt-urs(H). Linearized late mortality was
2.1%/pt-yrs(ISM), 1.1%/pt-ur(ISA), 1.8%/pt-yr(ISMA) and 1.8%/pt-yr(H).
Thromboembolic complication was experienced at the linearized rate of 1.045%/pt-yr(H), and bleeding complication at the rate of 0.871%/pt-yr(ISM), 0.63%/pt-yr(ISA), 0.205%/pt-yr(ISMA) and 0.729%/pt-yr(H), respectively. Prosthetic valve
endocarditis
occurred at the rat of 0.610%/pt-yr(ISM), 1.475%/pt-yr(ISA), 1.639%/pt-yr(ISMA) and 0.972%/pt-yr(H).
The linearized annual incidence of primary tissue failure was 1.655%/pt-yr(ISM), 1.475%/pt-yr(ISA), 1.639%/pt-yr(ISMA), 2.187%/pt-yr(H) and 1.785%/pt-yr(Group HM : MVR with Hancock valve). The incidence of tissue failure was significantly high in
the
patients younger than 30 years of age compared with the older patients.
The actuarial survival was 87.7±2.5% at 10 years(ISM), 94.3±3.2% at 11 years(ISA), 89.6±3.4% at 10 years(ISMA) and 81.3±6.6% at 12 years(HM). The freedom from thromboembolism was 93.2±2.0% at 10 years(ISM), 90.6±4.6% at 11 years(ISA),
95.8±2.5%
at 10 years(ISMA) and 80.9±11.1% at 12 years(HM). And, the freedom from primary tissue failure was 84.2±12.7at 10 years(ISMA) and 65.6±9.8% at 12 years(HM).
In conclusion, the standard Ionescu-Shiley and the Hancock bioprosthetic valves are excellent in their antithrombogenicity and long-term survival. However, the features of the structural failure with the prolonged follow-up beyond 10 years appear
to be
guarding, and the clinical indications of these bioprostheses seem to be quite limited.
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