Aim: An enhanced bileaflet valve, the Edwards MIRA feminine Mechanical Valve became available in 1998. Favorable hydrodynamic features and a redesigned sewing ring encouraged us to implant this device in indicated patients. Hemodynamics and clinical performance parameters were evaluated.
Methods: Between February 1998 and October 1999, 338 patients (171 males, 167 females) underwent native valve replacement with a MIRA prosthesis. Mean age 56.6+/-13.6 years, 320 patients were in NYHA class III/IV. Sixty-seven patients had echocardiographic examinations. Standard cardiopulmonary bypass was employed utilizing institutionally accepted implantation techniques. Aortic valve replacement was performed in 163 patients, mitral valve replacement in 134 patients, 35* double valve replacements and 1 triple valve replacement.
Results: Follow-up is 98% complete. Mean follow-up is 6.9+/-3.3 months (178.2 patient years). There were no operative deaths. Four early deaths were seen (1.18%). Late deaths reported in 12 patients. Linearized rate of late mortality was 6.7% per patient year (ppy). Overall actuarial survival at 13 months is 92.2%. Mean gradients and Effective Orifice Areas (EOA's) are comparable to other bileaflet valves. Linearized rates for valve-related complications was 4.49% ppy. Only 5 transient thromboembolic events (TE = 2.81% ppy) and 3 non-structural valve dysfunction events (NSVD = 1.68%) were seen. No reports of bleeding events, prosthetic endocarditis, valve thrombosis or structural valve deterioration. One patient required mitral valve reoperation for perivalvular leak.
Conclusions: Short-term hemodynamic and clinical results are comparable to other bileaflet valves. The sewing ring is non-obstructive, compliant with smoother needle penetration. Early clinical results are encouraging, follow-up should be continued.