Mitroflow aortic bioprosthesis 5-year follow-up: north american prospective multicenter study

Abstract

Background: The Mitroflow valve (Sorin Group, Milan, Italy) has been in use since 1982 and has shown long-term durability in large studies from European centers but has not been studied for long-term hemodynamics in large standardized multicenter trials. This study sought to assess the hemodynamics of the Mitroflow valve by extending the duration of follow-up in an ongoing prospective multicenter trial conducted in North America.

Methods: Six sites participated in this midterm study requiring annual follow-up and echocardiographic evaluation using a standardized transthoracic echocardiography acquisition protocol.

Results: There were 276 patients enrolled (age 74±8 years) and 54% were in New York Heart Association (NYHA) functional class III-IV. Follow-up from the time of valve implantation had a mean of 4.0±1.7 years with a cumulative follow-up of 1,102 patient-years. At 5 years of follow-up, 99% of patients were free of moderate or severe aortic regurgitation and 94% were in NYHA functional class I or II. Between baseline and 5 years, mean gradients increased an average of 0.4 to 4.3 mm Hg. The change in effective orifice area was appreciably small (-0.1 to -0.3 cm2) after 5 years. There were 57 deaths (4 early and 53 late) and 9 valve explants.

Conclusions: The Mitroflow valve implanted in the aortic position has shown to be hemodynamically stable over a 5-year follow-up in an elderly population with a high prevalence of comorbid conditions.