Incremental Benefit of Strain Rate Imaging to the Accuracy of Novice and Expert Interpreters of Dobutamine Stress Echocardiography

Abstract

Background: Dobutamine stress echo (DbE) is accurate for the detection of coronary artery disease (CAD), but interpretation is subjective and accuracy is dependent on observer experience. Strain rate imaging (SRI) offers a quantitative technique for identification of CAD, but it is unclear whether this could improve the results of less expert readers. Methods: We studied 121 pts (42 female, 64 ± 10 years) who underwent DbE, SRI, and coronary angiography. Segmental peak systolic SR (SR) was measured independently and previously derived cut-offs were applied to categorize segments as normal or abnormal. The accuracy of WMS by novice, experienced and expert readers, and SRI were compared with quantitative coronary angiography (significant CAD = QCA diameter stenosis >50%). Results: The accuracy of WMS by novice (57%, AUC 0.59) and experienced echocardiographers (67%, AUC 0.63) was less than experts in DbE (89%, AUC 0.67, p < 0.0001). By applying a cut-off of <−0.9 s−1, the accuracy of SR in the diagnosis of CAD was 89% (AUC 0.69), which added incremental value to the sensitivity of WMS by experienced readers, and significantly improved the sensitivity and specificity of WMS by novice readers (Table). SRI added specificity to the diagnosis of LAD territory disease by experienced and novice readers (88% versus 80%, p = 0.03, and 62%, p < 0.0001). SRI also improved the sensitivity in the diagnosis of postero-lateral territory disease in experienced and novice readers (86% versus 47%, p < 0.0001, and 41%, p < 0.0001). SRI did not add to the accuracy of expert readers. Conclusion: SRI offers an improvement in accuracy of WMS to less expert echocardiographers.