Suture technique in preventing dehiscence of prosthetic mitral valves

To evaluate suture techniques for mitral valve replacement, 60 fresh porcine hearts were used to determine suture holding strength. Using four techniques (simple interrupted, figure-of-eight, and horizontal without and with pledgets), the anterior leaflet, the posterior leaflet, and the commissures were sutured. The free ends of the sutures were then attached to a force transducer, and tension was increased until disruption occurred. In the anterior leaflet, horizontal mattress sutures disrupted with significantly less force than the other techniques. Pledgets increased the holding strength of mattress sutures, but figure-of-eight and simple interrupted sutures had greater holding strength than sutures with pledgets, suggesting that the direction of the suture vs that of tissue fibers is critical. Histologic studies confirmed this point. The posterior leaflet exhibited less holding strength than the anterior leaflet for all suture techniques but did not demonstrate a superiority for any specific technique. The posterior leaflet is the problem area for suture disruption from the mitral anulus. We secure mitral prostheses with horizontal mattress sutures with pledgets around the entire anulus, placing them from the atrial side.