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Comparison of Hancock I and Hancock II Bioprostheses
Author(s) -
Oury James H.,
Angell William W.,
Koziol James A.
Publication year - 1988
Publication title -
journal of cardiac surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 58
eISSN - 1540-8191
pISSN - 0886-0440
DOI - 10.1111/jocs.1988.3.3s.375
Subject(s) - medicine , stent , aortic valve , fixation (population genetics) , surgery , stenosis , cardiology , population , environmental health
The Hancock II bioprosthesis was developed in order to provide the advantageous low pressure fixation, improved deirin stent design, and anticalcification treatment. These changes were made 6 years ago after 10 years of experience with the high pressure fixed rigid implantation ring and polypropylene stent used in the Hancock I valve. In 1983, based on our own experience with low pressure fixed valves in 76 patients, we began early clinical trials with the Hancock II valve. All valves were studied postoperatively by intraoperative catheterization and followed up with postoperative echocardiograms for measurement of valve gradients and areas. This series of 104 patients with Hancock II valves was then compared retrospectively with 119 patients receiving Hancock I valves from 1975 to 1983. A comparison of mortality, thromboembolism, and hemorrhage rates was not significantly different between groups and the valve failure incidence of Hancock I valves was an anticipated 2.34% per patient‐year. There has been one primary tissue failure In the Hancock II series. This patient had fibrinous excrescences on the outlfow surface of the valve in the aortic position. These nodules were compatible with an old thrombotic process of ill‐defined nature. Further investigation resulted in reports of this phenomenon, which had resulted in early valve stenosis, from other centers implanting the Hancock II valve. In conclusion, the Hancock II bioprosthesis has theoretical advantages over the Hancock I in stent design, fixation pressure, and anticaicification potential. There is an unusual thrombotic process in aortic valve replacements that we have not observed in the Hancock I group or in our experience with other porcine xenografts. In our opinion, there should be further documentation that this process is not related to the T6 anticalcification treatment of the Hancock II porcine xenograft.