Long-term follow-up of morbidity and mortality after aortic valve replacement with a mechanical valve prosthesis

The aim of this study was to determine the incidence of valve-related complications in patients with a mechanical aortic valve prosthesis and to identify risk factors for an adverse outcome.

In the 424 patients, event-free survival rates 5 and 10 years after aortic valve replacement were 62% and 37%, respectively. The linearized incidence of thromboembolic events was 4.4% per patient-year, and of anticoagulant-related haemorrhage 8.5% per patient-year. Advanced NYHA functional class, atrial fibrillation, pure aortic regurgitation and thromboembolism prior to surgery decreased event-free survival. A history of pre-operative thromboembolism increased the risk for a first embolic event after aortic valve replacement (relative hazard [RH] 3.2), but was even more strongly associated with the risk for repeated events (> or =2 events, RH 5.4). After each thromboembolic episode that occurred, the risk for a subsequent one was increased. The risk for at least one, and up to three or more haemorrhages was increased in patients with a pre-operative history of bleeding (RH 3.3-5.1) and of atrial fibrillation (RH 1.8-3.9). The risk for a subsequent event was increased by a history of repeated haemorrhages, a short interval since previous bleeding, and high age.

There were few factors strongly related to valve related morbidity. However, previous bleedings and previous thromboembolism were powerful risk factors for repeated events.