Thrombosis and degeneration of Hancock valves: clinical and pathological findings.

Of 415 Hancock valves implanted in 370 patients, 26 valve specimens were recovered at postmortem examination and 8 at reoperation. In 9 of these 34, thrombosis had formed without apparent alteration of the heterograft tissue (Group A). All were mitral prostheses, and the thrombi were attached to the sewing ring.

Thromboembolic complications after mitral valve replacement with Hancock xenograft.

Case histories of 140 patients who had mitral valve replacement with the Hancock xenograft were reviewed according to the incidence of thromboembolic complications. There were 16 patients with preoperative and/or postoperative low-output syndrome (Group A.) Eight of these patients died, and six had autopsies which showed major thrombi on the heterograft valve.