A novel CFD based method for assessing the coronary microvascular dysfunction: combining coronary angiography and routine fractional flow reserve Running Title: CFD based method for assessing the CMD

Abstract

Background A novel computational fluid dynamics (CFD) based method was proposed for the measurement of intracoronary mean flow rate (Q) and absolute microvascular resistance (AMR) by combining coronary angiography and routine fractional flow reserve (FFR) measurement. The aim of this study is to explore the potential of the proposed method to assess the presence of coronary microvascular dysfunction (CMD). Methods Patients without hemodynamically significant coronary artery stenosis or those after a successful PCI were enrolled. Rest SPECT myocardial perfusion imaging (MPI) was employed as evidence for assessing the presence of CMD. Based on the sum rest score of target vessel (SRSTV), patients were divided into normal MPI group (SRSTV ≤ 1) and abnormal MPI group (SRSTV > 1). Q and AMR were obtained with a CFD based method during rest and hyperemia condition, and receiver operating characteristic (ROC) curve analyses were performed for discriminating patients with normal MPI and with abnormal MPI. Results A total of 57 patients with 61 target vessels were investigated. Based on SRSTV, 22 patients (38.6%) with 23 target vessels (37.7%) were associated with abnormal MPI. Compared with abnormal MPI group, the AMR was significantly lower in normal MPI group (1.97 ± 1.50 mmHg·s/ml vs 3.41 ± 2.30 mmHg·s/ml, p = 0.011), and the Q was significant higher in normal MPI group (0.94 ± 70 mmHg·s/ml vs 0.56 ± 0.50 mmHg·s/ml, p = 0.025). According to ROC curve analysis, the ROC-AUC of Q and AMR for discriminating normal MPI and abnormal MPI was 0.720(95% CI: 0.591–0.828, p = 0.001) and 0.731(95% CI: 0.602–0.836, p = 0.001). Conclusions The new CFD based method provides an easy and accurate way to measure the intracoronary flow rate and absolute microvascular resistance, and constitutes a new opportunity for assessing the presence of CMD.