Safety and diagnostic accuracy of stress Cardiac Magnetic Resonance imaging versus Exercise Tolerance Testing early after acute ST-Elevation Myocardial Infarction

¹ Academic Unit of Cardiovascular Medicine, University of Leeds, United Kingdom
² Department of Medical Physics, Leeds General Infirmary, United Kingdom
³ Cardiac Magnetic Resonance Unit, Leeds General Infirmary, United Kingdom

^* To whom correspondence should be addressed. E-mail: j.greenwood{at}leeds.ac.uk.

Accepted 2 January 2007

	Abstract

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 to standard exercise tolerance testing (ETT).

Design Cross sectional, observational study.

Setting University teaching hospital.

Patients Thirty-five 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 terms of identifying patients with significant coronary stenosis (70%) and the necessity for coronary revascularisation. Also, to determine if CMR can distinguish between ischaemia in the peri-infarct zone and ischemia 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) to detect significant coronary stenosis and more sensitive to predict revascularisation (94% vs. 56%, p=0.039). Inducible ischemia in the infarct related artery (IRA) 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.

Keywords: Magnetic resonance imaging, coronary heart disease, myocardial infarction, myocardial ischemia, myocardial perfusion