3D-Quantification of the no-reflow phenomenon with Delayed-Enhancement MR and clinical, electrocardiographic and bioumoral correlates

Background: No-Reflow (NR) phenomenon is considered a negative prognostic index in patients with acute myocardial infarction. Delayed contrast-enhanced magnetic resonance (DE-MR) can assess the presence, the size and location of NR. Aim: DE-MR evaluation and 3D-quantification of NR in the acute phase of ST elevation myocardial infarction (STEMI) in patient with singlevessel coronary artery disease treated with primary PTCA. Methods : 28 patients (mean age 62±12 years, male 23) underwent MR for evaluating DE and regional and global systolic function of left ventricle (LV) 6.6±3.2 days after PTCA. Global extent of DE (GDE) was calculated by tracing short axes of LV from the mitral valve plane to the apex. A software tool, allowing semi-automatic detection of endocardial and epicardial borders and DE areas, was used for quantifying the GDE and transmural extent of DE (TDE). The NR area was defined as a black area surrounded by a hyperenhanced area. A Wall motion Score Index (WMSI, from 1=normal to 4=dyskinetic in a 17 segment model of LV) was evaluated. Sigma ST (ST) was calculated as the sum of ST elevation (mm) in the 12 ECG leads registration. Results: There were no adverse effect during MR. Eleven patients (39%) had NR phenomenon (mean extent 8.8%±10.1) (NR group); 15 patients (53.5%) had DE without NR (HE group); 2 patients (7%) had no DE areas. History of CAD was more present in NR than in HE group (80% vs 33.3% p<0.015); cardiac enzymes values were similar in the 2 groups. ST was higher in NR than HE (mean 20.5±9.5 mm vs 9.8±6.8 mm, p<0.015). WMSI (NE 1.69±0.3 vs HE 1.33±0.2) was higher in NR than in HE. GDE was higher in NR than in HE (27.9±10.8% vs 11.2±7.21% p<0.0001); TDE was higher in NR than HE (31.5±13.3% vs 14±9.4% p<0.001); the number of LV segments with DE was higher in NR than HE (9.5±3.1 vs 6.3±3.4 p<0.019). At univariate analysis WMSI (p<0.01), GDE (p<0.008), TDE (p<0.008), ST (p<0.01) and history of CAD (p<0.05) were independent predictors of NR; at multivariate analysis GDE (p<0.01) was the only predictor of NR. Conclusions: DE-MRI is a usefull diagnostic tool to evaluate and three-dimensionally assess the presence, location and size of NR, and thus may be potentially used for the early prognostic stratification in patient with STEMI.