Remote Zone Extracellular Volume and Left Ventricular Remodeling in Survivors of ST-Elevation Myocardial Infarction
Jaclyn Carberry1, David Carrick1, Caroline Haig1
1From the BHF Glasgow Cardiovascular Research Centre (J.C., D.C., S.M.R., N.A., I.M., M.M., M.C.P., H.E., S.H., S.W., M.L., A.D., A.M., N.S., P.W., A.R., K.G.O., C.B.) and Robertson Centre for Biostatistics (C.H., I.F.), University of Glasgow, Glasgow, United Kingdom; and Golden Jubilee National Hospital, Dunbartonshire, United Kingdom (D.C., S.W., C.B.).
Insights
Extracellular volume (ECV) changes in the remote myocardium after ST-elevation myocardial infarction (STEMI) are linked to left ventricular remodeling. However, the small effect size limits ECV
Area of Science:
- Cardiology
- Radiology
- Biomedical Engineering
Background:
- Tissue remodeling in the remote myocardial zone after acute ST-elevation myocardial infarction (STEMI) is not fully understood.
- Cardiac magnetic resonance imaging (CMR) allows for extracellular volume (ECV) measurement in myocardial regions.
- The BHF MR-MI study investigated ECV changes post-STEMI.
Purpose of the Study:
- To assess the natural history and pathophysiological significance of myocardial tissue remodeling in the remote zone after acute STEMI.
- To evaluate the association between ECV in the remote zone and clinical factors.
- To determine if changes in remote zone ECV (ΔECV) correlate with left ventricular remodeling.
Main Methods:
- A cohort of 140 patients (2 days post-STEMI) and 131 patients (6 months post-STEMI) from the BHF MR-MI study underwent CMR.
- T1 mapping was used to measure ECV before and after gadolinium contrast administration.
- Multivariable regression analysis was employed to identify associations between ECV, ΔECV, and clinical parameters.
Main Results:
- Remote zone ECV was significantly lower than infarct zone ECV (25.6±2.8% vs. 51.4±8.9%).
- Left ventricular ejection fraction was inversely associated with remote zone ECV, while diabetes mellitus was positively associated.
- No ST-segment resolution and extent of ischemic area at risk were associated with ΔECV; ΔECV was associated with changes in left ventricular end-diastolic volume.
Conclusions:
- ΔECV is implicated in the pathophysiology of left ventricular remodeling post-STEMI.
- While ΔECV is associated with remodeling, its small effect size suggests limited clinical utility as a biomarker.
- Further research is needed to fully elucidate the role of tissue remodeling in the remote zone after STEMI.
Unlabelled:
The natural history and pathophysiological significance of tissue remodeling in the myocardial remote zone after acute ST-elevation myocardial infarction (STEMI) is incompletely understood. Extracellular volume (ECV) in myocardial regions of interest can now be measured with cardiac magnetic resonance imaging. Patients who sustained an acute STEMI were enrolled in a cohort study (BHF MR-MI [British Heart Foundation Magnetic Resonance Imaging in Acute ST-Segment Elevation Myocardial Infarction study]). Cardiac magnetic resonance was performed at 1.5 Tesla at 2 days and 6 months post STEMI. T1 modified Look-Locker inversion recovery mapping was performed before and 15 minutes after contrast (0.15 mmol/kg gadoterate meglumine) in 140 patients at 2 days post STEMI (mean age: 59 years, 76% male) and in 131 patients at 6 months post STEMI. Remote zone ECV was lower than infarct zone ECV (25.6±2.8% versus 51.4±8.9%; P<0.001). In multivariable regression, left ventricular ejection fraction was inversely associated with remote zone ECV (P<0.001), and diabetes mellitus was positively associated with remote zone ECV (P=0.010). No ST-segment resolution (P=0.034) and extent of ischemic area at risk (P<0.001) were multivariable associates of the change in remote zone ECV at 6 months (ΔECV). ΔECV was a multivariable associate of the change in left ventricular end-diastolic volume at 6 months (regression coefficient [95% confidence interval]: 1.43 (0.10-2.76); P=0.036). ΔECV is implicated in the pathophysiology of left ventricular remodeling post STEMI, but because the effect size is small, ΔECV has limited use as a clinical biomarker of remodeling.
Clinical Trial Registration:
URL: https://www.clinicaltrials.gov. Unique identifier: NCT02072850.
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