Patient prosthesis mismatch and its impact on left ventricular regression following aortic valve replacement in aortic stenosis patients

Abstract

Patient prosthesis mismatch is known to alter post-operative remodeling of left ventricle adversely in aortic stenosis patients. An indexed orifice area of 0.85 is considered as conventional cutoff for patient prosthesis mismatch based on hemodynamic principles. Many patients have smaller annulus and annulus enlargement techniques may be required to avoid this benchmark which complicates the surgery. To determine incidence of patient prosthesis mismatch (PPM) in our population, to assess left ventricle (LV) regression and impact of indexed effective orifice area on LV regression, and to determine a minimum acceptable cut off indexed orifice area that will result in LV regression. A single-center retrospective observational study of all patients who underwent aortic valve replacement surgery for severe aortic stenosis between July 2015 and December 2015 was conducted. Patients who underwent concomitant revascularization or other valve surgery were excluded. Data regarding conventional risk factors for PPM, valve type, and indexed orifice area as well as pre-operative and late post-operative LV mass were collected. Thirty-seven of the 91 patients satisfied inclusion criteria. All patients had significant regression in LV mass. The incidence of PPM was 68%. Regression of indexed left ventricular mass showed a positive correlation of with indexed effective orifice area of the prosthetic valve. The correlation coefficient is + 0.48 (95% CI 0.18-0.698). Left ventricular mass regression was significantly higher in patients with indexed effective orifice area more than 0.75 (68.89 ± 29 vs 122.55 ± 58.84, p = 0.028). Relative left ventricular regression also was significantly higher in patients with an indexed effective orifice area more than 0.75 (39.53 ± 13.13 vs 49.73 ± 15.56, p = 0.022). There is a positive correlation between left ventricular regression and the reduction in mean gradient achieved by valve replacement. The correlation coefficient was +0.35 (95% CI 0.03-0.61). The incidence of PPM was found to be comparable to literature. There is a positive correlation between left ventricular regression and indexed effective orifice area of the prosthetic valve. Left ventricular regression was significantly higher in patients with an indexed effective area more than 0.75. This can be considered as criteria for significant PPM in study population.