Safety and diagnostic accuracy of stress cardiac magnetic resonance imaging vs exercise tolerance testing early after acute ST elevation myocardial infarction

Objective: To determine the safety and diagnostic accuracy of adenosine- stress cardiac magnetic resonance (CMR) perfusion imaging early after acute ST elevation myocardial infarction (STEMI) compared with standard exercise tolerance testing (ETT). Design and setting: Cross sectional observational study in a university teaching hospital. Patients: 35 patients admitted with first acute STEMI. Interventions: All patients underwent a CMR imaging protocol which included rest and adenosine- stress perfusion, viability, and cardiac functional assessment. All patients also had an ETT (modified Bruce protocol) and x ray coronary angiography. Main outcome measures: Safety and diagnostic accuracy of adenosine- stress perfusion CMR vs ETT early after STEMI in identifying patients with significant coronary stenosis (> 70%) and the need for coronary revascularisation. Also, to determine if CMR can distinguish between ischaemia in the peri- infarct zone and ischaemia in remote myocardium. Results: CMR imaging was well tolerated (all patients completed the protocol) and no complications occurred. CMR was more sensitive (86% vs 48%, p = 0.0074) and more specific than ETT (100% vs 50%, p, 0.0001) for detecting significant coronary stenosis, and more sensitive for predicting revascularisation (94% vs 56%, p = 0.039). Inducible ischaemia in the infarct related artery territory was seen in 21 of 35 patients and was associated with smaller infarct size and less transmurality of infarction. Conclusions: Adenosine- stress CMR imaging is safe early after acute STEMI and identifies patients with significant coronary stenosis more accurately than ETT.