Prognostic Significance of CMR Findings in Patients with Known Coronary Artery Disease - Experience from a South Asian Country

Objectives: South Asians (SA) have a higher burden of coronary artery disease (CAD) and are known to have a worse prognosis compared to other ethnicities. Therefore, it is imperative to improve the risk stratification of SA patient with CAD and to seek out newer prognostic markers beyond the conventional echocardiography.The aim of this study was to investigate whether variables obtained by cardiac magnetic resonance (CMR) improve risk stratification of South Asian patients with known CAD. Material and Methods: We retrospectively analyzed 147 patients with evidence of CAD that had a CMR at our center between January 2011 and January 2019. LV volumes and regional wall motions were acquired by cine images, while infarct size (IS) was measured by late gadolinium enhancement. At a mean follow-up of 3.36 ± 2.22 years, cardiac events (non-fatal myocardial infarction, hospitalization due to heart failure, life-threatening arrhythmia, or cardiac death) occurred in 49 patients. An IS ≥35%, left ventricular ejection fraction (LVEF) ≤31%, and a wall motion score index (WMSI) ≥1.9 were strongly associated with follow-up cardiac events (P < 0.001). Patients that had none or less than 3 of these factors, showed a lower risk of cardiac events (HR 0.22 CI [0.11-0.44] P < 0.001 and HR 0.12 CI [0.04-0.32] P < 0.001, respectively) compared to those with all three factors. Conclusion: Integration of CMR derived factors such as IS and WMSI with LVEF can improve the prognostication of the SA population with CAD. Better risk stratification of patients can lead to improved and cost-effective therapeutic strategies to ameliorate the prognosis of these patients.