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


METHODS
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).


RESULTS
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.


CONCLUSIONS
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.


BACKGROUND
URL: https//www.clinicaltrials.gov. Unique identifier: NCT02072850.
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
David
D
Carrick
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Caroline
C
Haig
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Nadeem
N
Ahmed
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Jaclyn
J
Carberry
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Vannesa Teng
VT
Yue May
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Margaret
M
McEntegart
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Mark C
MC
Petrie
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Hany
H
Eteiba
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Mitchell
M
Lindsay
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Stuart
S
Hood
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Stuart
S
Watkins
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Andrew
A
Davie
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Ahmed
A
Mahrous
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Ify
I
Mordi
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Ian
I
Ford
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Aleksandra
A
Radjenovic
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.).
Keith G
KG
Oldroyd
From BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., I.M., A.R., K.G.O., C.B.), and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, UK; and West of Scotland Heart and Lung Centre, Golden Jubilee National Hospital, Clydebank, UK (D.C., N.A., J.C., V.T.Y.M., M.M., M.C.P., H.E., M.L., S.H.., S.W., A.D., A.M., I.M., K.G.O., C.B.). colin.berry@glasgow.ac.uk.
Colin
C
Berry
D000208:Acute Disease; D000368:Aged; D015331:Cohort Studies; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D006470:Hemorrhage / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D015425:Myocardial Reperfusion; D016017:Odds Ratio; D062645:Percutaneous Coronary Intervention; D011379:Prognosis; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000502:physiology
magnetic resonance imaging; microcirculation; myocardial infarction; prognosis