Page 61 - Advanced echocardiography in characterization and management of patients with secondary mitral regurgitation

Deja et al. (21) showed a trend toward improved survival in patients with a LVEF ≤35% and moderate-to-severe MR when adding mitral valve surgery to CABG versus CABG or medical treatment alone. Two randomized trials, evaluating the prognostic effect of transcatheter mitral valve treatment in patients with secondary MR, were recently published (1,2). Patients in the MITRA-FR trial did not benefit from transcatheter mitral valve treatment in terms of the combined endpoint of heart failure hospitalization and all-cause mortality, whereas in the COAPT trial, patients experienced a significantly lower rate of heart failure hospitalization and all-cause mortality as compared with patients receiving guideline-directed medical therapy. In the MITRA-FR trial, patients had larger LV volumes at baseline (LV end-diastolic volume index 136.2 ± 37.4 ml/m2 in the intervention group vs. 134.5 ± 33.1 ml/m2 in the control group) than did those included in the COAPT trial (LV end-diastolic volume 194.4 ± 69.2 ml in the intervention group vs. 191.0 ± 72.9 ml in the control group). This might reflect more advanced baseline LV disease in the MITRA-FR trial, which was not evident when comparing only the baseline LVEF (similar in both study populations). This finding emphasizes the fact that LVEF may overestimate LV systolic function in patients with secondary MR, owing to its load-dependent nature (22). LVEF may therefore not be the optimal parameter to select patients with secondary MR for intervention. Even in the presence of advanced LV systolic dysfunction, LVEF may be preserved, leading to the unmasking of LV disease after intervention, with subsequent poor outcome (16,22). Novel, more sensitive parameters for assessing LV systolic function in the presence of secondary MR, are therefore required.
LV GLS and outcome in secondary MR
Kamperidis et al. (5) demonstrated that LV GLS is a more sensitive marker of LV systolic dysfunction than is LVEF in patients with nonischemic dilated cardiomyopathy and significant secondary MR. Despite having comparable LVEF, patients with severe MR had more impaired LV GLS values than did those with mild MR. This highlights the fact that LV systolic dysfunction is better reflected by LV GLS than by LVEF in secondary MR. LV GLS has shown incremental prognostic value in addition to LVEF in patients with heart failure (23,24) and can be used in the risk stratification and timing of surgery in patients with aortic regurgitation and primary MR (25,26). However, the prognostic value of LV GLS in patients with secondary MR remained unknown.
This is the first study evaluating the incremental prognostic value of LV GLS (in addition to LVEF) in secondary MR. Patients with a more impaired LV GLS (<7.0%) experienced higher mortality rates than did those with a more preserved LV GLS (≥7.0%). Because no clear consensus exists whether intervention for secondary MR translates into
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