THROMBOEMBOLIC AND BLEEDING COMPLICATIONS AFTER MITRAL-VALVE REPLACEMENT

One thousand six hundred and sixty-eight consecutive patients who underwent isolated mitral valve replacement (MVR) from 1963 to 1984 were evaluated retrospectively. Thromboembolism occurred with a linearised rate of 2.5% ± 0.2%/patient-year (PY) for Starr-Edwards disc prosthesis Model6520, 2.4% ± 0.3%/PY for Bjørk-Shiley plane prosthesis, 3.0% ± 0.8%/PY for Bjørk-Shiley convexo-concave 60° prosthesis, 3.0% ± 0.8%/PY for St. Jude Medical prosthesis and 3.4% ± 0.5%/PY for Carpentier-Edwards tissue valve without the differences reaching significance. In the SJM group, the incidence of thromboembolism was significantly higher (P < 0.025) in smaller sizes (< M29) probably due to a more turbulent flow. The linearised rate for major haemorrhage was 1.6% ±0.1%/PY. Twenty-three percent of the thromboembolic and 18% of the bleeding events were fatal. Sixty-eight percent of the emboli involved the central nervous system and bleeding apart from fatalites was predominantly non-cerebral (81%). Whereas thromboembolism was a time-related event with more than twice as high a risk in the first postoperative year (4.2% ±0.5% vs. 1.7% ± 0.8%, P < 0.01), bleeding occurred with a constant rate over time (0.9% ± 0.4%). Adequacy of anticoagulation was an important risk factor for postoperative embolism with the prothrombin time (PT) exceeding the therapeutic range in 65% of all events. A preoperative history of embolism was the only additional patient-related risk factor forpostoperative embolism (18.3% vs. 9.6%, P < 0.001). In 30% of all haemorrhage, the PT was below 15%. Patients aged 60 or more years suffered significantly more bleeding events (13.3 % vs. 8.6%, P < 0.05). Careful anticoagulation is warranted in order to reduce thromboembolic and bleeding complications after MVR. © Springer-Verlag.