Angiographic validation of magnetic resonance assessment of myocardium at risk in non-ST-elevation myocardial infarction.

In the setting of acute myocardial ischemia, the hypoperfused portion of the myocardium is in danger of becoming irreversibly injured. This portion is called the area at risk (AAR). It is of clinical interest to be able to estimate the AAR for further evaluation and improvement of different revascularization strategies. The Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease Score (APPROACH-score) has been shown to be a jeopardy score with a good performance for angiographic assessment of the myocardium supplied by a coronary vessel, representing the AAR. Recently, cardiac magnetic resonance imaging (CMR) has been demonstrated to also provide good results in determining the AAR, especially in the setting of acute ST-elevation infarction patients. Therefore, the aim of our trial was to compare T2-weighted CMR imaging for assessment of AAR in patients with non-ST-elevation myocardial infarction (NSTEMI) and to validate this approach against the angiographic APPROACH-score. We enrolled sixty-four patients presenting with acute NSTEMI that underwent coronary X-ray angiography within 72 h of symptom onset. Two blinded readers performed offline angiographic AAR assessment using the modified APPROACH-score, as being described elsewhere. Furthermore, with the use of a semi-automatic T2w-CMR approach, the AAR was quantified by two fully blinded readers. The resulting mean AAR determined by the modified APPROACH-score was 28.6 ± 10.0 %. The mean CMR derived AAR was 27.6 ± 12.7 %. CMR assessment tended to slightly underestimate the AAR in comparison to angiographic scoring (difference -0.09 ± 7.6 %). There is a good correlation between the AAR assessed by CMR and by angiography (r = 0.65, p < 0.001). T2-weigthed CMR is able to quantify the AAR with very good correlation to the angiographic APPROACH-score in NSTEMI patients.