Seventeen-millimeter St. Jude Medical Regent valve in patients with small aortic annulus: dose moderate prosthesis-patient mismatch matter?

BACKGROUND: The study was designed to evaluate the effects of moderate prosthesis-patient mismatch (defined as 0.65 cm(2)/m(2) <indexed effective orifice area ≤ 0.85 cm(2)/m(2)) on midterm outcomes after isolated aortic valve replacement with a 17-mm St. Jude Medical Regent valve in a large series of patients, and to determine if these effects are influenced by patient confounding variables.

METHODS: One-hundred and six patients with and without moderate prosthesis-patient mismatch early after implantation of a 17-mm Regent valve at aortic position were included. Both clinical and echocardiographic assessments were performed preoperatively, at discharge and during follow-up period (mean follow-up time 52.6 ± 11.9 months).

RESULTS: The prevalence of moderate prosthesis-patient mismatch was documented in 46 patients (43.4%) at discharge. During the follow-up period, no difference in the regression of left ventricular mass, decrease of transvalvular pressure gradients, mortality and prosthesis-related complications was observed between patients with and without moderate prosthesis-patient mismatch. After adjustment for several risk factors, moderate prosthesis-patient mismatch was associated with increased midterm mortality in patients with baseline left ventricular ejection fraction<50% (HR: 1.80, p=0.02), but with normal prognosis in those with preserved LV function. Younger age (cut off value=65 years) was not an independent predictor of increased midterm mortality and valve-related complications in patients with moderate prosthesis-patient mismatch.

CONCLUSIONS: Moderate prosthesis-patient mismatch after aortic valve replacement with a small mechanical prosthesis is associated with increased mortality and adverse events in patients with pre-existing left ventricular dysfunction. Selected patients with small aortic annulus can experience satisfactory clinical improvements and midterm survival after aortic valve replacement with a 17-mm Regent valve.