Original Research
Coronary Microvascular Dysfunction Assessed by Pressure Wire and CMR After STEMI Predicts Long-Term Outcomes

https://doi.org/10.1016/j.jcmg.2021.02.023Get rights and content
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Abstract

Objectives

This study sought to evaluate the long-term prognostic implications of coronary microvascular dysfunction (CMD) when assessed with both cardiovascular magnetic resonance (CMR) and index of microcirculatory resistance (IMR) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

Background

Post-ischemic CMD can be assessed using the pressure-wire based IMR and/or by the presence of microvascular obstruction (MVO) on CMR.

Methods

A total of 198 patients with STEMI underwent IMR and MVO assessment. Patients were classified as follows: Group 1, no significant CMD (low IMR [≤40 U] and no MVO); Group 2, CMD with either high IMR (>40 U) or MVO; Group 3, CMD with both IMR >40 U and MVO. The primary endpoint was the composite of all-cause mortality, diagnosis of new heart failure, cardiac arrest, sustained ventricular tachycardia/fibrillation, and cardioverter defibrillator implantation.

Results

CMD with both high IMR and MVO was present in 23.7% of the cases (Group 3) and CMD with either high IMR or MVO was observed in 40.9% of cases (Group 2). At a median follow-up of 40.1 months, the primary endpoint occurred in 34 (17%) cases. At 1 year of follow-up, Group 3 (hazard ratio [HR]: 12.6; 95% confidence interval [CI]: 1.6 to 100.6; p = 0.017) but not Group 2 (HR: 7.2; 95% CI: 0.9 to 57.9; p = 0.062) had worse clinical outcomes compared with those with no significant CMD in Group 1. However, in the long-term, patients in Group 2 (HR: 4.2; 95% CI: 1.4 to 12.5; p = 0.009) and those in Group 3 (HR: 5.2; 95% CI: 1.7 to 16.2; p = 0.004) showed similar adverse outcomes, mainly driven by the occurrence of heart failure.

Conclusions

Post-ischemic CMD predicts a more than 4-fold increase in long-term risk of adverse outcomes, mainly driven by the occurrence of heart failure. Defining CMD by either invasive IMR >40 U or by CMR-assessed MVO showed similar risk of adverse outcomes.

Key Words

cardiovascular magnetic resonance
coronary microvascular dysfunction
heart failure
index of microcirculatory resistance
microvascular obstruction
primary percutaneous coronary intervention
prognosis
ST-segment elevation myocardial infarction

Abbreviations and Acronyms

CMD
coronary microvascular dysfunction
CMR
cardiovascular magnetic resonance
HF
heart failure
IMR
index of microcirculatory resistance
IQR
interquartile range
IS
infarct size
LVEF
left ventricle ejection fraction
MVO
microvascular obstruction
PPCI
primary percutaneous coronary intervention
STEMI
ST-segment elevation myocardial infarction
TIMI
Thrombolysis In Myocardial Infarction

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The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.

Drs. Scarsini and Shanmuganathan are joint first authors.

†Drs. Scarsini, Shanmuganathan, Channon, and Banning contributed equally to this work.