Long-term outcomes after valve replacement for low-gradient aortic stenosis - Impact of prosthesis-patient mismatch

Background - The long-term outcomes of patients with low-gradient aortic stenosis (LGAS) after aortic valve replacement (AVR) are poorly defined. The purpose of this study was to define the long-term outcomes of LGAS patients after AVR and to evaluate the potential impact of prosthesis-patient mismatch (PPM) in these patients. Methods and Results - A cohort of 664 patients undergoing AVR for aortic stenosis after 1990 were followed-up prospectively with annual clinical assessment and echocardiography (total follow-up 3447 patient-years; mean follow- up 5.2 +/- 3.3 years). LGAS was defined as an aortic valve area < 1.2 cm(2), a mean transvalvular pressure gradient < 40 mm Hg, and a left ventricular (LV) ejection fraction < 50%, and was present in 79 patients. Rates and correlates of survival, freedom from congestive heart failure (CHF), and LV mass regression after AVR were determined using multivariate regression methods. Ten-year survival and freedom from CHF after AVR were 72.7 +/- 7.5% and 68.2 +/- 9.5%, respectively, for patients with LGAS, compared with 89.6 +/- 1.8% and 84.1 +/- 4.2% for patients without LGAS (hazard ratio [HR] for death and postoperative CHF, 3.1 +/- 1.1 and 2.7 +/- 0.9, respectively; P < 0.01). In LGAS patients, PPM, defined as an indexed effective orifice area <= 0.85 cm(2)/ m(2), was independently associated with increased rates of CHF ( HR, 3.6 +/- 2.2; P = 0.039), impaired LV mass regression (P = 0.037), and a trend toward increased late mortality (HR, 3.0 +/- 1.9; P = 0.084). Conclusions - Patients with LGAS have worse long-term outcomes after AVR compared with patients without LGAS. PPM adversely affects the long-term outcomes of LGAS patients and should be avoided in this population.