Myocardial hemorrhage after acute reperfused ST-segment–elevation myocardial infarction: relation to microvascular obstruction and prognostic significance

D Carrick, C Haig, N Ahmed, M McEntegart… - Circulation …, 2016 - Am Heart Assoc
D Carrick, C Haig, N Ahmed, M McEntegart, MC Petrie, H Eteiba, S Hood, S Watkins…
Circulation: Cardiovascular Imaging, 2016Am Heart Assoc
Background—The success of coronary reperfusion therapy in ST-segment–elevation
myocardial infarction (MI) is commonly limited by failure to restore microvascular perfusion.
Methods and Results—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 …
Background
The success of coronary reperfusion therapy in ST-segment–elevation myocardial infarction (MI) is commonly limited by failure to restore microvascular perfusion.
Methods and Results
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.
Conclusions
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.
Clinical Trial Registration
URL: http://www.clinicaltrials.gov. Unique identifier: NCT02072850.
Am Heart Assoc