Relationship between myocardial blush grades, staining, and severe microvascular damage after primary percutaneous coronary intervention a study performed with contrast-enhanced magnetic resonance in a large consecutive series of patients.

BACKGROUND: Although angiographic perfusion has been traditionally evaluated by myocardial blush grade (MBG), pathophysiologic features underlying different MBG and the persistent blush, traditionally called staining, have been poorly explained. The aim of the study was to evaluate the correlation between MBG and morphologic aspects on cardiac magnetic resonance (CMR). METHODS: Myocardial blush grade and morphologic aspects on contrast-enhanced CMR, with special reference to staining phenomenon and persistent microvascular damage (PMD), were evaluated in a consecutive series of patients with acute myocardial infarction (AMI) treated by primary percutaneous coronary intervention. RESULTS: A total number of 294 AMI patients were enrolled and classified into 2 groups, that is, MBG 0/1 (115, 39%) and MBG 2/3 (179, 61%), according to the angiographic profile. By comparing MBG 0/1 versus MBG 2/3 patients, the former exhibited a larger enzymatic infarct size (P < .001) and a greater infarct size index (P < .001) and PMD (P < .001). In the MBG 0/1 group, a subgroup of 51 patients with staining phenomenon (MBG 0 staining) was also identified, with a worse CMR profile as PMD (P < .001). Multivariate analysis confirmed the strong association between MBG 0/1 and mean number of segments with transmural necrosis (odds ratio 1.62, 95% CI 1.17-2.24, P = .003) and PMD index (odds ratio 3.13, 95% CI 1.19-8.29, P = .021). CONCLUSIONS: In AMI patients treated by primary percutaneous coronary intervention, angiographic parameters of impaired reperfusion correlate with PMD as detected by contrast CMR. Among patients with MBG 0, the presence of the so-called staining phenomenon identifies a subgroup of patients with more severe PMD.

The contribution of intramyocardial hemorrhage to the "no-reflow phenomenon": a study performed by cardiac magnetic resonance.

BACKGROUND: Percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) is sometimes complicated by microvascular damage and hemorrhage. Hemoglobin degradation products have magnetic susceptibility effects which help in detecting hemorrhagic AMI by T2 -weighted cardiac magnetic resonance (CMR) images. OBJECTIVES: To investigate the possibility to detect intramyocardial hemorrhage after AMI and to assess its contribution to the delayed hypoenhanced core on late gadolinium enhancement (LGE) CMR, a feature traditionally referred to as microvascular obstruction. METHODS: Consecutive patients with AMI who underwent PCI and CMR were investigated. Hypointense zones T2 -weighted images were labelled as "hemorrhagic" AMI. Areas of late hypoenhancement on LGE CMR were considered as regions of persistent microvascular damage (PMD). Only transmural AMI were considered. RESULTS: A total number of 108 transmural AMI patients were eventually enrolled and divided into two groups according to the presence of hypoenhancement on T2 images. Thirty-two patients showed an hypointense stria within the high signal intensity zone on T2 -weighted images; all these patients showed midmural PMD on LGE. Among the remaining 76 patients, only 14 (18.4%) showed PMD in the subendocardial region. The angiographic outcome was worse in patients with hemorrhagic AMI, with a lower prevalence of TIMI 3 (65.6% vs. 96.1%, P = 0.017) and higher prevalence of myocardial blush grade 0 (84.4% vs. 13.2%, P < 0.001) post-PCI. CONCLUSIONS: T2 -weighted CMR in reperfused AMI allows identification of hemorrhage, related to PMD areas on LGE images and to a worse reperfusion profile on angiography. These features open new avenues of investigation for prognostic assessment of reperfused AMI.

At-admission risk stratification for in-hospital life-threatening ventricular arrhythmias and death in non-ST elevation myocardial infarction patients.

AIMS: Identification of patients with non-ST elevation acute myocardial infarction (NSTEMI) at higher risk of in-hospital life-threatening ventricular arrhythmias (LT-VA) and death is crucial for determining appropriate levels of care/monitoring during hospitalisation. We assessed predictors of in-hospital LT-VA and all-cause mortality in a consecutive series of NSTEMI patients. METHODS AND RESULTS: We prospectively studied 1325 consecutive patients (69.7% males, median age 70 (61-79) years) presenting with NSTEMI and undergoing continuous electrocardiographic monitoring. The primary study end-point was the occurrence of spontaneous (unrelated to coronary interventions) in-hospital LT-VA, including sustained ventricular tachycardia and ventricular fibrillation; the secondary end-point was in-hospital mortality from all causes. Of 1325 patients, 21 (1.5%) experienced LT-VA and 62 (4.7%) died from either arrhythmias (n=1) or other causes (n=61). Seven of the 20 patients who survived LT-VA subsequently died of heart failure. Independent predictors of in-hospital LT-VA were the Global Registry of Acute Coronary Events (GRACE) score >140 (odds ratio (OR)=7.5; 95% confidence interval (CI) 1.7-33.3; p=0.008) and left ventricular ejection fraction (LV-EF)<35% (OR=4.1; 95% CI 1.7-10.3; p=0.002). GRACE score >140 (OR=14.6; 95% CI 3.4-62) and LV-EF <35% (OR=4.4; 95% CI 1.9-10) also predicted in-hospital all-cause death. The cumulative probability of in-hospital LT-VA and death was respectively 9.2% and 23% in the 98 (7.4%) patients with GRACE score >140 and LV-EF<35%, while it was respectively 0.2% and 0% among the 627 (47.3%) with GRACE score ≤140 and LV-EF ≥35%. CONCLUSIONS: Simple risk stratification at admission based on GRACE score and echocardiographic LV-EF allows early identification of NSTEMI patients at higher risk of both in-hospital LT-VA and all-cause mortality.