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 cm2, 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 < or = 0.85 cm2/m2, 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.