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Myocardial longitudinal strain reserve as a marker of severity of coronary artery disease during dobutamine stress echocardiography

Background Timely and prompt detection of coronary artery disease (CAD) is of paramount importance for patient management in daily clinical practice. Several noninvasive stress tests are available for evaluating CAD, of which dobutamine stress echocardiogram (DSE) is widely available for localization and extent of CAD. However, wall-motion analysis during DSE is subjective, so two-dimensional speckle tracking-derived longitudinal strain has been recently presented to allow quantitative assessment of global and regional wall motions. Aim To assess longitudinal strain reserve (LSR) during DSE test in predicting severity of CAD in chronic stable patients. Patients and methods The study included 48 patients with chronic stable angina referred to DSE unit. Patients were classified into two groups according to Gensini score: group 1 had Gensini score less than 20 (mild CAD) and group 2 had Gensini score more than or equal to 20 (severe CAD). All patients were subjected to complete history taking, full general and cardiac examination, ECG analysis, DSE test, and two-dimensional speckle-tracking echocardiography, where global longitudinal strain was measured at rest and at peak dobutamine stress, then LSR was measured, then average territorial longitudinal strain (TLS) of the three major epicardial arteries [left anterior descending (LAD), left circumflex artery (LCX), and right coronary artery (RCA)] was measured, and then selective coronary angiography results were used for Gensini score calculation. Results There was a statistically significant difference between the study groups regarding stress global longitudinal strain and LSR. Regarding TLS of LAD, there was a statistically significant difference between the study groups regarding average stress and regional strain reserve of LAD territory. Regarding TLS of LCX, there was a statistically significant difference between the study groups regarding stress and regional strain reserve of LCX territory. There was a significant inverse correlation between LSR and Gensini score (r=−0.79, P ≤ 0.001), with multivariate logistic regression stating age, smoking, and diabetes are significant predictors of low LSR in the study population. Regarding TLS of RCA, there was a statistically significant difference between the study groups regarding rest and stress RCA territory. We found a cutoff value of LSR that can significantly predict severe CAD, which was 2.9, and at a cut-off value of 2.7, LSR can significantly predict left main equivalent disease. Conclusions LSR is a significant predictor of severe CAD at a cutoff value of 2.9. In addition, LSR can significantly predict left main equivalent disease at a cutoff value of 2.7.