Echocardiographic assessment of left ventricular mechanics in individuals with mitral valve prolapse: a systematic review and meta-analysis.

ABSTRACT

PURPOSE: During the last decade, a number of echocardiographic studies have employed speckle tracking echocardiography (STE) for assessing myocardial deformation properties in individuals with mitral valve prolapse (MVP), reporting not univocal results. Accordingly, we performed a systematic review and meta-analysis to summarize the main findings of these studies and to examine the overall influence of MVP on left ventricular (LV) global longitudinal strain (GLS). METHODS: All echocardiographic studies assessing conventional echoDoppler parameters and myocardial strain indices in MVP individuals vs. controls without MVP, selected from PubMed and EMBASE databases, were included. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment of Case-Control Studies. Continuous data (LV-GLS) were pooled as a standardized mean difference (SMD) comparing MVP group with healthy controls. The overall SMD of LV-GLS was calculated using the random-effect model. RESULTS: The full-texts of 15 studies with 1088 individuals with MVP and 591 healthy controls were analyzed. Average LV-GLS magnitude was significantly, even though modestly, reduced in MVP individuals in comparison to controls (19.4 ± 3.4% vs. 21.1 ± 2.8%, P < 0.001). The overall effect of MVP on LV-GLS was small-to-medium (SMD - 0.54, 95%CI -0.76,-0.32, P < 0.001). Substantial heterogeneity was detected for the included studies, with an overall I2 statistic value of 75.9% (P < 0.001). Egger's test for a regression intercept gave a P-value of 0.58, indicating no publication bias. On meta-regression analysis, none of the moderators (the age, the percentage of females among MVP individuals, body mass index, heart rate and systolic blood pressure of MVP individuals, the degree of mitral regurgitation, the type of ultrasound machine employed for strain echocardiographic imaging and finally the beta blocker treatment) was significantly associated with effect modification (all P < 0.05). Regional strain analysis, performed by two-third of the studies, highlighted a more enhanced reduction in myocardial strain parameters at level of the LV basal infero-lateral segments in all directions (longitudinal, circumferential and radial), with apical sparing. CONCLUSIONS: The longitudinal strain impairment detected in MVP individuals is more regional than global, with peculiar involvement of the LV basal infero-lateral segments and relative apical sparing pattern.