Utility of Global Longitudinal Strain in Mitral Regurgitation: A Systematic Review

Background: The assessment of myocardial function is important in both primary and secondary mitral regurgitation (MR), to determine the timing of interventions and to predict outcomes. Ejection fraction is relied on for clinical decisions, even though, it is well understood that it does not reflect myocardial function. Global longitudinal strain (GLS) is a promising parameter that correlates well with outcomes postinterventions. In this review, we aimed to determine the utility of GLS in both primary and secondary MR in predicting clinical outcomes. We also aimed to determine the GLS cutoff at which clinical decisions can be made. Methods: We conducted a systematic review of the literature regarding the use of GLS as a predictor of left ventricular (LV) function. We searched PubMed and Embase for relevant articles and identified 141 articles after removing duplicates. We screened titles and abstracts to identify 28 relevant articles from which data were extracted. Results: In 16 of the 28 studies, patients had primary MR mostly of degenerative etiology and the LV GLS cutoff for events ranged from −17.2% to −21%. In 10 studies, patients with secondary MR were included, and a cutoff ranging from −7%− to −9% was most often reported except for one study that reported-16.3%, as it included patients with atrial functional MR. Conclusion: GLS assesses LV dysfunction and is a good predictor of clinical and echocardiographic outcomes postinterventions. Values lower than the cutoff value of −17.2% to −21% in primary MR and −7% to −9% in secondary MR are associated with poorer outcomes. These findings suggest that the use of GLS as a routine assessment in patients with significant MR may be appropriate for both clinical decision-making and prognostication.