Coronary Angiography-Derived Index of Microvascular Resistance

Abstract

A coronary angiography-derived index of microvascular resistance (caIMR) is proposed for physiological assessment of microvasular diseases in coronary circulation. The aim of the study is to assess diagnostic performance of caIMR, using wire-derived index of microvascular resistance (IMR) as the reference standard. IMR was demonstrated in 56 patients (57 vessels) with stable/unstable angina pectoris and no obstructive coronary arteries in three centers using the Certus pressure wire. Based on the aortic pressure wave and coronary angiograms from two projections, the caIMR was computed and assessed in blinded fashion against the IMR at an independent core laboratory. Diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of the caIMR with a cutoff value of 25 were 84.2% (95% CI: 72.1% to 92.5%), 86.1% (95% CI: 70.5% to 95.3%), 81.0% (95% CI: 58.1% to 94.6%), 88.6% (95% CI: 76.1% to 95.0%), and 77.3% (95% CI: 59.5% to 88.7%) against the IMR with a cutoff value of 25. The receiver-operating curve had area under the curve of 0.919 and the correlation coefficient equaled to 0.746 between caIMR and wire-derived IMR. Hence, caIMR could eliminate the need of a pressure wire, reduce technical error, and potentially increase adoption of physiological assessment of microvascular diseases in patients with ischemic heart disease.

Diagnostic Value of Angiography-Derived IMR for Coronary Microcirculation and Its Prognostic Implication After PCI

“…The angio-IMR measurement was conducted as described before using commercialized software (FlashAngio, Rainmed Ltd., Suzhou, China) (12). In brief, a three-dimensional reconstruction of coronary arteries was firstly conducted for the target vessels, followed by the estimation of angio-FFR by computational pressure-flow dynamics with a validated method (5); the estimated hyperemic Pa (Pa hyp ) was assumed by mean arterial pressure (MAP) during the index procedure-MAP×0.2 when MAP ≥95 mmHg or MAP-MAP × 0.15 when MAP <95 mmHg (5).…”

Diagnostic performance and prognostic impact of coronary angiography‐based Index of Microcirculatory Resistance assessment: A systematic review and meta‐analysis

“…In total, we included ten reports from eight studies. Among them, eight reports from six studies were included in the analysis of diagnostic accuracy 18–23 and four studies that evaluated the prognostic information of angio‐IMR were included in the analysis of adverse cardiovascular outcomes 18,22,24,25…”

“…In total, we included ten reports from eight studies. Among them, eight reports from six studies were included in the analysis of diagnostic accuracy [18][19][20][21][22][23] and four studies that evaluated the prognostic information of angio-IMR were included in the analysis of adverse cardiovascular outcomes. 18,22,24,25 Most of the included studies were prospective cohort studies and a total of 1653 coronary lesions were analyzed for the computation of angio-IMR.…”

Computational Pressure-Fluid Dynamics Applied to Index of Microcirculatory Resistance, Predicting the Prognosis of Drug-Coated Balloons Compared With Drug-Eluting Stents in STEMI Patients

“…The CPFD-IMR measurement was conducted using the software (FlashAngio, Rainmed Ltd., Suzhou, China, Figure 1 ) as described before ( Ai et al, 2020 ). In brief, a three-dimensional reconstruction of coronary arteries was firstly conducted for the target vessels, followed by the estimation of caIMR by CPFD with a validated method ( Li et al, 2020 ).…”