Comparative Prognostic Utility of Indexes of Microvascular Function Alone or in Combination in Patients With an Acute ST-Segment-Elevation Myocardial Infarction.

Primary percutaneous coronary intervention is frequently successful at restoring coronary artery blood flow in patients with acute ST-segment-elevation myocardial infarction; however, failed myocardial reperfusion commonly passes undetected in up to half of these patients. The index of microvascular resistance (IMR) is a novel invasive measure of coronary microvascular function. We aimed to investigate the pathological and prognostic significance of an IMR>40, alone or in combination with a coronary flow reserve (CFR≤2.0), in the culprit artery after emergency percutaneous coronary intervention for acute ST-segment-elevation myocardial infarction. Patients with acute ST-segment-elevation myocardial infarction were prospectively enrolled during emergency percutaneous coronary intervention and categorized according to IMR (≤40 or >40) and CFR (≤2.0 or >2.0). Cardiac magnetic resonance imaging was acquired 2 days and 6 months after myocardial infarction. All-cause death or first heart failure hospitalization was a prespecified outcome (median follow-up, 845 days). IMR and CFR were measured in the culprit artery at the end of percutaneous coronary intervention in 283 patients with ST-segment-elevation myocardial infarction (mean±SD age, 60±12 years; 73% male). The median IMR and CFR were 25 (interquartile range, 15-48) and 1.6 (interquartile range, 1.1-2.1), respectively. An IMR>40 was a multivariable associate of myocardial hemorrhage (odds ratio, 2.10; 95% confidence interval, 1.03-4.27; P=0.042). An IMR>40 was closely associated with microvascular obstruction. Symptom-to-reperfusion time, TIMI (Thrombolysis in Myocardial Infarction) blush grade, and no (≤30%) ST-segment resolution were not associated with these pathologies. An IMR>40 was a multivariable associate of the changes in left ventricular ejection fraction (coefficient, -2.12; 95% confidence interval, -4.02 to -0.23; P=0.028) and left ventricular end-diastolic volume (coefficient, 7.85; 95% confidence interval, 0.41-15.29; P=0.039) at 6 months independently of infarct size. An IMR>40 (odds ratio, 4.36; 95% confidence interval, 2.10-9.06; P<0.001) was a multivariable associate of all-cause death or heart failure. Compared with an IMR>40, the combination of IMR>40 and CFR≤2.0 did not have incremental prognostic value. An IMR>40 is a multivariable associate of left ventricular and clinical outcomes after ST-segment-elevation myocardial infarction independently of the infarction size. Compared with standard clinical measures of the efficacy of myocardial reperfusion, including the ischemic time, ST-segment elevation, angiographic blush grade, and CFR, IMR has superior clinical value for risk stratification and may be considered a reference test for failed myocardial reperfusion. URL: https//www.clinicaltrials.gov. Unique identifier: NCT02072850.

Carrick D ，Haig C ，Ahmed N ，Carberry J ，Yue May VT ，McEntegart M ，Petrie MC ，Eteiba H ，Lindsay M ，Hood S ，Watkins S ，Davie A ，Mahrous A ，Mordi I ，Ford I ，Radjenovic A ，Oldroyd KG ，Berry C ... -  《-》

Microvascular resistance of the culprit coronary artery in acute ST-elevation myocardial infarction.

Carrick D ，Haig C ，Carberry J ，May VTY ，McCartney P ，Welsh P ，Ahmed N ，McEntegart M ，Petrie MC ，Eteiba H ，Lindsay M ，Hood S ，Watkins S ，Mahrous A ，Rauhalammi SM ，Mordi I ，Ford I ，Radjenovic A ，Sattar N ，Oldroyd KG ，Berry C ... -  《JCI Insight》

Comparative Significance of Invasive Measures of Microvascular Injury in Acute Myocardial Infarction.

Maznyczka AM ，Oldroyd KG ，Greenwood JP ，McCartney PJ ，Cotton J ，Lindsay M ，McEntegart M ，Rocchiccioli JP ，Good R ，Robertson K ，Eteiba H ，Watkins S ，Shaukat A ，Petrie CJ ，Murphy A ，Petrie MC ，Berry C ... -  《-》

The Dynamic Relationship Between Invasive Microvascular Function and Microvascular Injury Indicators, and Their Association With Left Ventricular Function and Infarct Size at 1-Month After Reperfused ST-Segment-Elevation Myocardial Infarction.

Demirkiran A ，Robbers LFHJ ，van der Hoeven NW ，Everaars H ，Hopman LHGA ，Janssens GN ，Berkhof HJ ，Lemkes JS ，van de Bovenkamp AA ，van Leeuwen MAH ，Nap A ，van Loon RB ，de Waard GA ，van Rossum AC ，van Royen N ，Nijveldt R ... -  《-》

Myocardial Hemorrhage After Acute Reperfused ST-Segment-Elevation Myocardial Infarction: Relation to Microvascular Obstruction and Prognostic Significance.

The success of coronary reperfusion therapy in ST-segment-elevation myocardial infarction (MI) is commonly limited by failure to restore microvascular perfusion. We performed a prospective cohort study in patients with reperfused ST-segment-elevation MI who underwent cardiac magnetic resonance 2 days (n=286) and 6 months (n=228) post MI. A serial imaging time-course study was also performed (n=30 participants; 4 cardiac magnetic resonance scans): 4 to 12 hours, 2 days, 10 days, and 7 months post reperfusion. Myocardial hemorrhage was taken to represent a hypointense infarct core with a T2* value of <20 ms. Microvascular obstruction was assessed with late gadolinium enhancement. Adverse remodeling was defined as an increase in left ventricular end-diastolic volume ≥20% at 6 months. Cardiovascular death or heart failure events post discharge were assessed during follow-up. Two hundred forty-five patients had evaluable T2* data (mean±age, 58 [11] years; 76% men). Myocardial hemorrhage 2 days post MI was associated with clinical characteristics indicative of MI severity and inflammation. Myocardial hemorrhage was a multivariable associate of adverse remodeling (odds ratio [95% confidence interval]: 2.64 [1.07-6.49]; P=0.035). Ten (4%) patients had a cardiovascular cause of death or experienced a heart failure event post discharge, and myocardial hemorrhage, but not microvascular obstruction, was associated with this composite adverse outcome (hazard ratio, 5.89; 95% confidence interval, 1.25-27.74; P=0.025), including after adjustment for baseline left ventricular end-diastolic volume. In the serial imaging time-course study, myocardial hemorrhage occurred in 7 (23%), 13 (43%), 11 (33%), and 4 (13%) patients 4 to 12 hours, 2 days, 10 days, and 7 months post reperfusion. The amount of hemorrhage (median [interquartile range], 7.0 [4.9-7.5]; % left ventricular mass) peaked on day 2 (P<0.001), whereas microvascular obstruction decreased with time post reperfusion. Myocardial hemorrhage and microvascular obstruction follow distinct time courses post ST-segment-elevation MI. Myocardial hemorrhage was more closely associated with adverse outcomes than microvascular obstruction. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02072850.

Carrick D ，Haig C ，Ahmed N ，McEntegart M ，Petrie MC ，Eteiba H ，Hood S ，Watkins S ，Lindsay MM ，Davie A ，Mahrous A ，Mordi I ，Rauhalammi S ，Sattar N ，Welsh P ，Radjenovic A ，Ford I ，Oldroyd KG ，Berry C ... -  《-》