Midterm results with the Sorin Monostrut heart valve prosthesis

OBJECTIVE: To monitor the hematological and clinical sequelae of a single tilting disc cardiac valve prosthesis. DESIGN: Prospective nonrandomized trial. SETTING: University teaching hospital. PARTICIPANTS: All patients receiving a single mechanical cardiac valve prosthesis were offered the Sorin Monostrut valve if they met the criteria for valve use. Seventy-five per cent of the patients entered were in New York Heart Association (NYHA) functional class III or IV. One hundred and forty-seven patients were subsequently followed at three months and then yearly after valve implantation for seven years. MAIN OUTCOME MEASURES: At one year, preoperative indexes of hemolysis were compared with three-month and one-year postoperative values. Actuarial curves for survival, freedom from cerebrovascular events and explantation were constructed for the seven-year follow-up period. RESULTS: Hemolysis, as measured by lactate dehydrogenase values, commonly occurs preoperatively, remaining significantly elevated three months and one year following valve implantation. Serum haptoglobin was normal preoperatively but was significantly low at one year. Anemia was uncommon and most patients had normal reticulocyte counts at one year. At three years, 81% of patients were in NYHA functional class I. CONCLUSIONS: Midterm results show that this valve is structurally reliable and meets all current requirements for a safe mechanical valve.