Prognostic implications of left ventricular strain by speckle-tracking echocardiography in the general population: a meta-analysis

Purpose: Left ventricular (LV) mechanics by speckle-tracking echocardiography (STE) is prognostic in patients with cardiovascular diseases, but evidence related to community-dwelling individuals is uncertain. We therefore performed a systematic review and meta-analysis of STE as a predictor of adverse outcomes in the general population. Methods: PRISMA guidelines were followed and MEDLINE and EMBASE were searched to identify eligible studies. Primary outcome was all-cause mortality and secondary outcomes were composite cardiac and cardiovascular end-point. Random effects meta-analysis was performed, and a modified Newcastle-Ottawa Assessment Scale was used for quality assessment. Results: Eight papers matched the predefined criteria (total number of individuals studied=11,744). All publications assessed global longitudinal strain (GLS) by two-dimensional speckle-tracking echocardiography (2D-STE), one assessed circumferential, radial and transverse strains, and one assessed GLS-derived post-systolic shortening. None assessed LV rotational measures in association with outcomes. Two studies reported associations between GLS and all-cause mortality and composite cardiovascular end-point. Six papers reported an association between GLS and composite cardiac end-point, three of which were from the same study. Four papers were suitable for meta-analysis. GLS predicted all-cause mortality (pooled minimally adjusted HR per unit strain (%)=1.07 [95% CI 1.03-1.11], p=0.001), and composite cardiovascular (pooled maximally adjusted HR=1.18 [1.09-1.28], p<0.0001) and cardiac (HR=1.08 [1.02-1.14], p=0.006) end-points. GLS also predicted coronary heart disease (HR=1.15 [1.03-1.29], p=0.017) and heart failure (HR=1.07 [1.02-1.13], p=0.012). The quality of all studies was good. Conclusions: This study provides some evidence that STE may have utility as a measure of cardiac function and risk in the general population. 2D-STE-based GLS predicts total mortality, major adverse cardiac and cardiovascular end-points in community-dwelling individuals in a limited number of studies. Despite this, this systematic review also highlights important knowledge gaps in the current literature and further evidence is needed regarding the prognostic value of LV mechanics in unselected older populations.