Influence of patient-prosthesis mismatch on postoperative outcome after aortic valve replacement for pure aortic stenosis in the presence of impaired left ventricular contractility

OBJECTIVES: To assess the effects of patient/prosthesis mismatch (PPM) (EOAI < 1 cm2/m2) on postoperative results of patients submitted to aortic valve replacement (AVR) for pure valve stenosis with concomitant left ventricular dysfunction (LVEF ≤ 40%). The persistence of left ventricular outflow tract obstruction after AVR might affect postoperative results in the presence of LV contractile impairment. METHODS: From January 1989 to December 2001, 201 patients submitted to AVR for pure aortic valve stenosis and affected by LV dysfunction (mean LVEF 30±6.8%) were retrospectively identified. After surgery, 161 patients had no PPM whereas PPM was present in 40 patients (mean EOAI 0.87±0.07 cm2/m2). All patients were followed up in terms of postoperative survival, morbidity and functional capacity. Univariate and Cox regression analysis were carried out to evaluate predictors of postoperative outcome. RESULTS: Follow up was 99,8% complete, and 985 patients/year were available for the analysis. No differences were found between the two groups in terms of demographics, except for age (73±9 years in PPM group, and 67±11 years in the second group, respectively). Adjusted Kaplan-Meyer estimations did not show any difference between the two groups in terms of postoperative event-free outcomes. Postoperative functional capacity improved in the majority of the patients, irrespective of the presence of PPM. At multivariate analysis PPM did not show to represent a negative determinant of postoperative outcome, whereas advanced age and NYHA class were predictive of unfavorable results. CONCLUSIONS: After AVR for pure aortic stenosis in the presence of LV dysfunction, PPM did not apparently influence mortality and morbidity outcomes. Further investigations are necessary to elucidate LV response in this setting.