Syed Waqar Ahmed1, Fateh Ali Tipoo Sultan1, Safia Awan1
1Aga Khan University Hospital, Karachi, Pakistan
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. Hence 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.
We retrospectively analysed 147 patients with evidence of CAD that had a CMR at our centre between January 2011 to January 2019. LV volumes and regional wall motions were acquired by cine images, while infarct size was measured by late gadolinium enhancement. Evidence of CAD was determined by ECG features of prior myocardial infarction (MI), previous clinical records or angiographic evidence of CAD.
At a mean follow-up of 3.36 ± 2.22 years, cardiac events (non-fatal Myocardial Infarction, hospitalisation due to heart failure, life-threatening arrhythmia or cardiac death) occurred in 49 patients. An infarct size ≥ 35%, 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 three 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.
Integration of CMR derived factors like Infarct size 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.