Abstract 18325: Comparative and Incremental Diagnostic and Prognostic Yield of Exercise ECG, CMR and SPECT in Patients With Suspected Ischaemic Heart Disease: A CE-MARC Sub-Study

Abstract

Background: Guidelines recommend exercise ECG and stress imaging as first line diagnostic tests for the management of patients with suspected ischemic heart disease (IHD). We compared 1) the accuracy in detection of angiographically defined IHD and 2) the prognostic significance of exercise ECG, single photon emission computed tomography (SPECT) and cardiovascular magnetic resonance (CMR), as well as the sequential use of exercise ECG and an imaging test, in the CE-MARC study. Methods and Results: Of 752 patients in CE-MARC, 580 had exercise ECG and angiography, and 503 also had SPECT and CMR. The sensitivity, specificity, positive and negative predictive values (95%CI) of exercise ECG were 68.3 (61.9,74.0), 72.5 (67.6,76.9), 61.0 (54.8,66.8), 78.4 (73.7,82.5). Exercise ECG was significantly less sensitive than CMR and less specific than CMR and SPECT. Furthermore a positive exercise ECG result was not predictive of MACE at follow-up (HR 1.14 [95% CI 0.75 to 1.72], p = 0.53). Sequential SPECT following an inconclusive exercise ECG compared to SPECT alone resulted in improved sensitivity (86.3% vs. 65.5%) and negative predictive value (79.0% vs. 87.9%) but at a cost of reduced specificity and positive predictive values (83.7% vs. 64.1%; 72.1% vs. 60.7%), and was not prognostically significant (HR 2.31 [95% CI, 0.88 to 6.08], p = 0.091). CMR alone had greater diagnostic and prognostic yield than exercise ECG, SPECT or a combination of the two. Sequential CMR in patients with inconclusive exercise ECG did not outperform CMR alone, but allowed effective prognostication (p = 0.011), contrary to SPECT (p = 0.081). Conclusions: In patients recruited to CE-MARC, exercise ECG was less sensitive than CMR and less specific than both CMR and SPECT. Positive exercise ECG results had no clear prognostic value. CMR alone was more sensitive and offered greater prognostic yield than exercise ECG, SPECT, or a combination of both. Diagnostic and prognostic yield of CMR was not improved by combination with exercise ECG. Importantly, sequential use of CMR, but not SPECT, improved prognostication following an inconclusive exercise ECG.