The Journal of Thoracic and Cardiovascular Surgery, Vol 90, 741-749, Copyright © 1985 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Long-term comparative analysis of the Bjork-Shiley and Hancock valves implanted in 1975
J Martinell, J Fraile, V Artiz, J Moreno and G Rabago
The long-term results in all patients undergoing isolated mitral, aortic,
or double mitral-aortic heart valve replacement operated upon in 1975 has
been retrospectively analyzed. A total of 153 patients received the
standard Bjork-Shiley (flat pyrolytic disc) mechanical prostheses and 150
patients received the noncomposite Hancock porcine xenograft. Overall
operative mortality was not significantly different between groups. All
patients receiving a Bjork-Shiley prosthesis, but none in the Hancock
group, received long-term anticoagulant therapy. Medium and long-term
actuarial survival rates (5 and 10 years postoperatively) were comparable
for the two groups (88% for Bjork- Shiley and 84% for Hancock [NS] at 5
years; 86% for Bjork-Shiley and 80% for Hancock at 10 years [NS]). The
incidence of systemic embolism was similar in the two groups (1.6% +/- 0.4%
per patient-year for the Bjork-Shiley group and 1.3% +/- 0.3% per
patient-year for the Hancock group [NS]). Also the incidence of
endocarditis was similar (0.6% +/- 0.2% per patient-year for the
Bjork-Shiley group and 0.8% +/- 0.3% per patient-year for the Hancock group
[NS]). In the Hancock group the overall incidence of reoperations was
significantly higher than in the Bjork-Shiley group (4.2% +/- 0.6% per
patient-year versus 0.9% +/- 0.3% per patient-year (p = 0.001). The major
cause for reoperation in the Hancock group was primary tissue failure (3%
+/- 0.5% per patient- year). In the Bjork-Shiley group the major cause of
reoperation was valve thrombosis (0.5% +/- 0.2% per patient-year).
Therefore, accepting the fact that other bioprostheses may behave
differently from the Hancock noncomposite xenograft, we currently restrict
our indications for valve replacement with bioprostheses.