Longitudinal strain impairment in organic mitral regurgitation: look beyond the valve

Abstract Aims Global longitudinal strain (GLS) is a hallmark of cardiac damage in mitral regurgitation (MR). GLS > −18% in patients with severe organic MR (OMR) and normal LV ejection fraction (LVEF) is an independent predictor of postoperative LV dysfunction. While it is known that GLS is impaired in less than severe functional ischaemic MR (FMR), the value of GLS in less than severe OMR is not known. We aimed to determine prevalence and determinants of any GLS impairment in OMR, in comparison to FMR. Methods We retrospectively evaluated 51 consecutive patients (33 OMR and 18 FMR) with mild-to-moderate, moderate and moderate-to-severe MR (Table*). Overall, GLS was higher in OMR than FMR (17.9±4.5 vs. 10.3±5.3, P<0.001), with rate of impairment of 45% in OMR and 89% in FMR (P= 0.0024). Results However, no significant difference was found in GLS between mild-to-moderate, moderate and moderate-to-severe MR patients within OMR (17.7±4.7 vs. 16.9±3.9 vs. 22.4±3, respectively, P>0.05), as well as FMR (9.8±6.6 vs. 10.7±5.3 vs. 10.4±5.3, respectively, P>0.05) groups. GLS correlated directly with left ventricular (LV) ejection fraction (EF) in both OMR (r=0.69, P<0.001) and FMR (r=0.90, P<0.001), and inversely with LV mass indexed for body surface area (LVMi) in both OMR (r = −0.50, P=0.005) and FMR (r = −0.48, P=0.042). While correlation with LVEF was better for FMR than OMR (Z − 1.95, P=0.026), correlation with LVMi was similar for OMR and FMR groups (Z − 0.082, P>0.05). Conclusions In patients with OMR, GLS may be reduced, despite normal LVEF, in less than severe MR. Prevalence and degree of GLS impairment in OMR is less than in FMR. In OMR, as well as in FMR, GLS impairment is independent of entity of MR, but rather correlates with LVMi, maybe reflecting impact of myocardial fibrosis derived by increased LVMi on GLS.