Resting global longitudinal strain and stress echocardiography to detect coronary artery disease burden

Stress echocardiography (SE) is a recommended diagnostic method in patients with suspected coronary artery disease (CAD).1 Resting global longitudinal strain (GLS), coronary flow velocity reserve in the left-anterior descending coronary artery (CFVR-LAD) and delta wall motion score index (d-WMSI) on SE have proven prognostic value.2,3 Diagnostic accuracy comparison of these parameters for the detection of CAD and CAD burden is lacking. The aim of this study was to compare the diagnostic accuracy of resting left-ventricular (LV) function variables (LVEF and GLS), and the stress-derived d-WMSI and CFVR-LAD in order to estimate the presence and the increasing severity of CAD. All consecutive patients who underwent SE for suspected CAD and coronary anatomy evaluation (invasive or not) within 90 days from SE were enrolled from 1 January 2009 to 31 December 2020 at the Parma University Hospital (Parma, Italy). The exclusion criteria were i) known heart disease or ii) poor acoustic window. All patients underwent transthoracic echocardiography at rest and SE with dipyridamole and contrast media for LV border enhancement (SonoVue, Bracco Imaging, Milan, Italy).4 Resting GLS measurements were calculated and expressed in absolute values by blinded operators (N.G., D.T.), after the recruitment was complete, using Philips QLAB software (version 10.7). The wall motion score index was calculated at baseline and at peak stress using a 17-segment model of the LV. The CFVR-LAD was calculated as the hyperemic and basal peak diastolic coronary velocity ratio.4 Obstructive CAD was defined as the presence of a luminal reduction of ≥50% in the epicardial vessels. The modified Duke Prognostic Index was used to classify CAD burden according to the extension, location, and coronary stenosis severity.5 Patients with Duke Prognostic Index class >5 were defined as having severe CAD burden.