Downstream testing after exercise ECG stress test – can we predict ischemia on subsequent vasodilator stress cardiac magnetic resonance?
Authors: Gabaldon-Perez A , Marcos-Garces V , Merenciano-Gonzalez H , Nunez-Marin G , Lorenzo-Hernandez M , Gavara J , Perez-Sole N , De Dios E , Bonanad C , Racugno P , Lopez-Lereu M P , Monmeneu J V , Chorro F J , Bodi V 
Published: October 2021

Abstract

Background
Exercise ECG stress test (ExECG) is useful in the diagnostic work-up of patients with chest pain and known or suspected stable ischemic heart disease (SIHD). However, current guidelines recommend a stress imaging, ischemia-detecting technique such as vasodilator stress cardiac magnetic resonance (vs-CMR) if available. Whether clinical and ExECG variables can predict ischemia on subsequent vs-CMR testing is unknown.

Material and methods
We retrospectively included 289 patients who underwent an ExECG and a subsequent vs-CMR in the year after this test and who didn't undergo a revascularization procedure in this time frame. Clinical, ExECG and vs-CMR variables were included in the registry. vs-CMR was considered positive if ischemia was evident in at least one myocardial segment on stress first-pass perfusion without concomitant necrosis on late gadolinium enhancement imaging. We performed univariate and multivariate analysis to check for the association of variables with the risk of ischemia on vs-CMR.

Results
Mean time from ExECG to vs-CMR was 97,27±88,31 days and 91 vs-CMR were positive for ischemia. Age, male sex, diabetes mellitus, hypertension, dyslipidaemia and personal history of ischemic heart disease, percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) were predictors of ischemia on vs-CMR in the univariate analysis. On ExECG, time of exercise, exercise capacity, chest pain during ExECG, maximum heart rate (HR) and systolic blood pressure (SBP), % of predicted HR, chronotropic reserve index, maximum and reserve of double product and Duke Treadmill Score were also associated with ischemia on vs-CMR. However, the only independent predictors on multivariate binary logistic regression stepwise analysis were history of PCI (HR 3.79 [2.03–7.09], p&lt;0.001) or CABG (HR 5.57 [1.80–17.26], p=0.003), maximum double product (HR 0.94 [0.90–0.99] per 1000 increase, p=0.02) and Duke Treadmill Score (HR 0.95 [0.91–0.99], p=0.019). Subgroup analysis showed that male sex (HR 1.95 [1.16–3.28], p=0.012), history of ischemic heart disease (HR 4.73 [2.88–7.76], p&lt;0.001) and maximum double product (HR 0.94 [0.90–0.98] per 1000 increase, p=0.006) were predictors of ischemia on vs-CMR in non-revascularized patients (n=212). In revascularized patients (n=77) the only independent predictor was the Duke Treadmill Score on ExECG (HR 0.93 [0.86–0.99], p=0.048).

Conclusions
Several ExECG variables, namely Duke Treadmill Score and parameters of myocardial oxygen consumption such as maximum doble product, can predict the risk of ischemia on subsequent vs-CMR in revascularized and non-revascularized patients with chest pain. This can help select patients who should undergo vs-CMR afeter ExECG for ischemia detection.

Funding Acknowledgement
Type of funding sources: None.