Midterm follow-up of unstented biological valves.

We have used the stentless aortic biosprosthesis for aortic valve replacement during the last 10 years. Since 1988, 647 stentless aortic prosthesis were implanted: 384 unstented heterografts, 176 Ross procedures, and 87 homografts. Patients up to age 50 were offered the Ross procedure, those between the ages of 50 and 60 a homograft, and patients 60 years old and older received heterografts. All patients were evaluated at our clinic. An echocardiogram was obtained before discharge from the hospital, at 3 to 6 months postoperatively, and yearly thereafter. Gradients, regurgitation, and effective orifice area were recorded at each visit. The patient was also evaluated clinically. Early mortality rate was 5.4%, 1.7%, and 5.8% for heterograft, autograft, and homograft, respectively. The mean gradient for the unstented porcine valve was 7.6 mm Hg at 3 to 6 month but 5 mm Hg or less for the homografts or autografts. Unstented valves are relatively new but they showed superior hemodynamic performance compared with either mechanical or biological stented valves. Anticoagulation is not mandatory, which should decrease the number of complications. They are the replacement of choice for young and old patients with a small aortic root and are the best alternative to the natural valve.