Coronary microvascular dysfunction assessed by pressure wire and CMR after STEMI predicts long-term outcomes

Journal article

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.

Authors: Scarsini, R; Shanmuganathan, M; De Maria, GL; Borlotti, A; Kotronias, RA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: JACC: Cardiovascular Imaging
• Volume: 14
• Issue: 10
• Pages: 1948-1959
• Publication date: 2021-04-14
• Acceptance date: 2021-02-25
• DOI: 10.1016/j.jcmg.2021.02.023
• EISSN: 1876-7591
• ISSN: 1936-878X
• Pmid: 33865789
• Language: English
• Keywords: cardiovascular magnetic resonance; FFR; microvascular obstruction; coronary microvascular dysfunction; index of microcirculatory resistance; ST-segment elevation myocardial infarction; primary percutaneous coronary intervention; heart failure; prognosis