Can resting segmental strain identify obstructive coronary artery disease in chronic coronary syndrome patients referred to CABG?

BACKGROUND: Noninvasive identification of patients with chronic coronary syndrome (CCS) with obstructive coronary artery disease (CAD) remains a clinical challenge. Strain imaging enables detection of subtle myocardial dysfunction at rest and may serve as a sensitive marker of multivessel or left main CAD. This study aimed to assess whether segmental systolic strain at rest can identify patients with obstructive CAD referred for coronary artery bypass grafting (CABG), and to compare diagnostic performance of tissue Doppler imaging strain with two-dimensional speckle-tracking echocardiography in a retrospective analysis of a selected CABG-referred cohort. METHODS: This retrospective study included 61 patients with CCS and obstructive CAD referred for CABG and 61 age- and sex-matched healthy controls from the population-based Nord-Trøndelag Health Study. All participants underwent echocardiography with both tissue Doppler and speckle-tracking strain analysis. The number of hypokinetic segments within one heart was counted, determined at different segmental peak longitudinal strain thresholds of -8% to -16%. The area under curve (AUC) using receiver operating characteristic analysis was used to evaluate diagnostic performance. Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (MRI) was used to assess myocardial scarring. RESULTS: LGE MRI confirmed that 78% of patients had no visible myocardial scar and that overall scar burden was low (2.8%). At a hypokinetic strain threshold of -8%, tissue Doppler strain demonstrated excellent diagnostic accuracy for identifying myocardial dysfunction in CABG-referred patients (AUC 0.95, 95% CI 0.91-1.00), performing at least as well as speckle-tracking strain (AUC 0.79, 95% CI 0.70-0.87). Tissue Doppler strain identified obstructive CAD with 95% sensitivity and 86% specificity. Comparable AUCs were found in a subgroup of 20 patients without coronary occlusion or myocardial scarring, indicating that regional hypokinesia was equally detectable in patients with normal EF and no LGE-defined scars. CONCLUSION: Segmental strain imaging at rest-by both tissue Doppler and speckle tracking-can detect subclinical regional dysfunction in CABG-referred patients with obstructive CAD, even in patients with preserved global left ventricular function and no evidence of myocardial scarring. Tissue Doppler strain showed at least as high diagnostic accuracy as speckle-tracking strain. These findings underscore the clinical potential of resting segmental strain analysis as a sensitive, noninvasive tool for identifying obstructive CAD in this selected CABG-referred population.