[Short- and long-term changes in left ventricular function after surgical correction of mitral regurgitation]

After surgical treatment of mitral regurgitation (MR) left ventricular dysfunction (LVD) can appear, which is an important predictive factor of long-term morbidity and mortality. The aim of our retrospective study was the assessment of left ventricular function (LVF) with M-mode echo measurement in the early and late postoperative period. Between 01. 01. 1992. and 31. 12. 1996. 70 patients with MR (29 men, 41 women, mean age 53.8 years) had at least three M-mode echoes: before surgery (I.), after surgery within 1 year (II.) and after the first postoperative year (mean 2.4 years) (III.). The patients were divided into subgroups: a) prosthetic valve replacement (MB) 58 patients, valvuloplasty (PL) 12 patients, b) coronary bypass grafting (C) 12 patients, no coronary disease (NC) 58 patients, c) chordal rupture (R) 24 patients, other etiology (NR) 46 patients. The evaluation of LVF was based on the ejection fraction (EF) calculated from the end-diastolic (Dd) and end-systolic (Ds) diameters on M-mode echo. Statistical analysis was made by paired and unpaired t test and with correlation analysis. The Dd decreased in the whole group (T) and in all subgroups in the II. and III. measurements compared to the I. (T: 58.9 vs. 52.6 vs. 53.2 mm; p < 0.0001, p < 0.0001). The Ds did not change in any group. In all groups except C the EF decreased at the II. measurement compared to the I. values (T: 57.7 vs. 47.8%, p < 0.0001; MB: 56.6 vs. 46.6%, p < 0.0001; PL: 62.8 vs. 53.8%, p = 0.05; NC: 59.6 vs. 48.3%, p < 0.0001; R: 61.5 vs. 50.4%, p < 0.0003; NR: 55.6 vs. 46.5% p = 0.0002), and it remained significantly lower in the III. measurement as well. At the III. measurement the EF was below 55% in all groups. In the groups T, MB, NC, NR the EF increased at the III. measurement compared to the II. (W: 47.8 vs. 51.3%, p = 0.002; PVR: 46.6 vs. 51.4%, p = 0.001; NC: 48.3 vs. 52.8%, p = 0.005; NR: 46.5 vs. 49.9%, p = 0.05). In the group C the I., II., III. EF values were not significantly different. There were 33 patients with preoperative EF more than 60%. In this group the EF decreased at the II. measurement, but the III. measurement showed normalization of the EF (67.03 vs. 52.58 vs. 59.27%, p < 0.0001, p < 0.01). There was no strong correlation between the preoperative EF, Ds and early or late postoperative EF (r = 0.54, r = -0.58; r = 0.62, r = -0.56). In patients operated for MR the postoperative EF is diminished independently on the preoperative EF, the operative technique or etiology. Left ventricular dysfunction concealed by the volume overload is unmasked by the decreased EF in the early postoperative period. LVD is partly reversible in the majority of the cases, however complete reversibility takes place only in cases with preoperative EF over 60%. Hence the operation of MR in patients with EF less than 60% is considered to be too late for the reversibility of LVD.