Low Cardiac Output Syndrome: Incidence after Mitral Valve Replacement with or without Preservation of Mitral Valve Apparatus.

Standard mitral valve replacement in patients with chronic mitral valve regurgitation and mitral valve stenosis consistently results in a decrease in early postoperative left ventricular ejection performance. Some studies showed that preservation of mitral valve leaflet and subvalvular apparatus can reduce postoperative left ventricular dysfunction. On the basis of the concept, this randomized clinical trial comparing mitral valve replacement with preservation of mitral subvalvular apparatus and conventional mitral valve replacement performed in National Institute of Cardiovascular Diseases (NICVD), Dhaka, Bangladesh, in the period of July 2010 to December 2011. We included 60 patients of mitral regurgitation and mitral stenosis, among them 30 patients underwent mitral valve replacement with preservation of mitral subvalvular apparatus (Group A) and 30 patients underwent conventional mitral valve replacement (Group B). There was no significant difference between two groups in terms of peri-operative variables. But there was significant higher incidence of Low cardiac output (LOS) syndrome [36.7% vs. 6.9% (p<0.05)] and congestive heart failure in Group B than Group A. The duration of ICU stay was also significantly higher in conventional mitral valve replacement group [113.23±11.30 hours vs. 96.23±20.02 (p=0.001)]. Additionally, there was significantly less fall of left ventricular ejection fraction in preservation of mitral subvalvular apparatus group [preop 65.27±5.45, at discharge 54.31±3.78, after 3 months 58.28±5.20 (p<0.0001)] than conventional group [preop 66.43±4.58, at discharge 46.43±3.87, after 3 months 46.55±3.63 (p<0.0001)]. In this study left ventricular ejection fraction was used as measure of left ventricular function. We postulate that, this relative preservation of left ventricular ejection fraction was likely the result of preservation of mitral subvalvular apparatus.