In patients with coronary artery disease undergoing PCI, an angiography-derived IMR ≥25.1 was associated with a significantly higher risk of cardiac death or heart failure readmission (HR 9.66).
Cohort (n=138)
Blinded core laboratory analysis
Yes
Does angiography-derived IMR accurately diagnose microcirculatory dysfunction and predict cardiac death or heart failure readmission in patients with CAD after PCI?
Angiography-derived IMR is a pressure-wire-free index that accurately identifies microcirculatory dysfunction and independently predicts long-term risk of cardiac death or heart failure readmission after PCI.
Hazard Ratio: 9.66 (95% CI 2.04–45.65)
Absolute Event Rate: 18.6% vs 5.4%
p-value: p=0.004
Background: Angiography-derived index of microcirculatory resistance (angio-IMR) is an emerging pressure-wire-free index to assess coronary microvascular function, but its diagnostic and prognostic value remains to be elucidated. Methods and Results: The study population consisted of three independent cohorts. The internal diagnostic cohort enrolled 53 patients with available hyperemic microcirculatory resistance (HMR) calculated from myocardial blood flow and pressure. The external diagnostic cohort included 35 ischemia and no obstructive coronary artery disease (INOCA) patients and 45 controls. The prognostic cohort included 138 coronary artery disease (CAD) patients who received PCI. Angio-IMR was calculated after the estimation of angiography-derived fractional flow reserve (angio-FFR) using the equation of angio-IMR = estimated hyperemic Pa × angio-FFR × vessel length/(K × V diastole ). The primary outcome was a composite of cardiac death or readmission due to heart failure at 28 months after index procedure. Angio-IMR demonstrated a moderate correlation with HMR (R = 0.74, p 0.001) and its diagnostic accuracy, sensitivity, specificity, and area under the curve to diagnose INOCA were 79.8, 83.1, 78.0, and 0.84, respectively, with a best cut-off of 25.1. Among prognostic cohort, patients with angio-IMR ≥25.1 showed a significantly higher risk of cardiac death or readmission due to heart failure than those with an angio-IMR 25.1 (18.6 vs. 5.4%, adjusted HR 9.66, 95% CI 2.04–45.65, p = 0.004). Angio-IMR ≥25.1 was an independent predictor for cardiac death or readmission due to heart failure (HR 11.15, 95% CI 1.76–70.42, p = 0.010). Conclusions: Angio-IMR showed a moderate correlation with HMR and high accuracy to predict microcirculatory dysfunction. Angio-IMR measured after PCI predicts the risk of cardiac death or readmission due to heart failure in patients with CAD. Clinical Trial Registration: Diagnostic and Prognostic Value of Angiography-derived IMR (CHART-MiCro), NCT04825028.
Dai et al. (Fri,) conducted a cohort in Coronary artery disease (CAD) (n=138). Angiography-derived IMR ≥25.1 vs. Angiography-derived IMR <25.1 was evaluated on Composite of cardiac death or readmission due to heart failure (HR 9.66, 95% CI 2.04-45.65, p=0.004). In patients with coronary artery disease undergoing PCI, an angiography-derived IMR ≥25.1 was associated with a significantly higher risk of cardiac death or heart failure readmission (HR 9.66).