Photo Credit: Ustas7777777

The following is a summary of “Angiography-versus wire-based microvascular resistance index to detect coronary microvascular obstruction associated with ST-segment elevation myocardial infarction,” published in the September 2024 issue of Cardiology by Wang et al.

Microvascular obstruction (MVO) assessed by cardiac magnetic resonance (CMR) after ST-segment elevation myocardial infarction (STEMI) holds significant prognostic value. While the invasive index of microvascular resistance (IMR) predicts MVO, the role of angiography-based IMR remains unclear. 

Researchers conducted a prospective study comparing wire-based IMR with angiography-derived IMR (Angio-IMR) in detecting MVO following STEMI. 

They undertook patients with a first STEMI and multivessel disease to a CMR imaging detection of MVO and had both angio-IMR and IMR measurements taken during primary percutaneous coronary intervention (PPCI) and at a 30-day follow-up. This was done for both STEMI culprit and non-culprit vessels.

The study included 58 patients (mean age 60.7 ± 9.9 years, 82% male). At PPCI, angio-IMR and IMR showed a strong correlation (r=0.70, P<0.001) and agreement (coefficient 0.58). Both predicted MVO well [Angio IMR: AUC 0.79 (95% CI: 0.667-0.928); IMR: AUC 0.70 (95% CI: 0.539-0.853), P=0.15] with cuts-off of Angio-IMR 40 U and IMR 34 U. In non-culprit vessels, angio-IMR and IMR also correlated well (rho=0.59, P<0.001) but had lower mean values compared to culprit vessels (Angio-IMR: 36 vs. 23; IMR: 39 vs. 22, P<0.001). 

Investigators concluded that Angio-IMR is a reliable alternative to wire-based IMR predicting MVO in patients with STEMI. Both methods showed a strong correlation in acute and subacute phases in both culprit and non-culprit vessels.

Source: sciencedirect.com/science/article/abs/pii/S0167527324008787