The Impact of Sub-valvular Apparatus Preservation on Prosthetic Valve Dysfunction During Mitral Valve Replacement

Sub-valvular apparatus preservation (SAP) during mitral valve replacement (MVR) is not a new concept. Some surgeons prefer to excise the apparatus. The aim of this study was to reduce the risk of prosthetic valve dysfunction. This retrospective study included 151 patients with the mean age of 46 years who underwent MVR (Female/male = 93/58). In the group I consisting of 39 patients, MVR with chordae preservation was performed (Bi-leaflet preservation = 20; posterior leaflet preservation = 19). In the group II consisting of 112 patients, sub-valvular apparatus was resected completely during MVR. Preoperative patients’ characteristics, including age, sex, functional status, left ventricular ejection fraction, and end-diastolic or end-systolic dimensions were statistically similar in both groups. Mean follow-up period was 60.3 ± 26 months. The improvement of functional status was seen in almost all survivors but was more obvious in the group I. In early follow-up, 56.4% of group I cases and 44.1% of group II patients were classified as New York Heart Association class I. These rates were 84.2% and 71.2% in mid-term follow-up, respectively (P < 0.001). Mortality rate was significantly lower in the group I (2.6%) compared to the group II (8.9%) (P = 0.03). There was a trend for higher frequency of postoperative atrial fibrillation in the group II compared to that in the group I (52.7% vs. 38.5%, P = 0.12).The incidence of prosthetic valve dysfunction (PVD) was 5.1% in the group I and 4.5% in the group II, but this difference was not statistically significant (P = 0.56). Preservation of mitral annulus and papillary muscle continuity may enhance post- MVR cardiac performance with low mortality and morbidity rates. The risk of PVD was not significantly higher than conventional MVR in our series.