Assessment of Diffusely Diseased Coronary Artery by Instantaneous Wave-Free Ratio Co-Registration versus Quantitative Coronary Angiography

Purpose: Coronary physiological assessment is now routinely applied in the catheter laboratory to guide percutaneous coronary intervention (PCI). Currently most physiological assessment is performed in a binary manner to determine whether a vessel requires intervention. Although studies have reported the high diagnostic efficiency of physiological assessment in minimizing the number of vessels requiring treatment, it is widely recognized that interrogation of individual stenosis in the presence of tandem lesions or diffuse disease under hyperemic conditions makes PCI planning complex and less practical. The aim of this study was to perform assessment of severity of coronary lesions of a pressure guide wire with continuous instantaneous wave-free ratio (iFR) co-registration measurement compared coronary angiography and quantitative coronary analysis (QCA) aiming to minimize the procedure, decrease number and length of stents used. Methodology: This non randomized controlled trial was conducted at Cardiology Department, Benha University, National Heart Institute (NHI) from February 2020 to September 2022. The study included a group of 30 patients presented with diffuse coronary artery disease and undergoing elective PCI. Findings: The study found out that the distribution of risk factors among studied groups was HTN representing 54%, regarding DM 60%, concerning dyslipidemia 64% and smokers represented 57%. The median of expected length of stent using QCA assessment was 40.2 mm with standard deviation (SD) (8mm) higher than detected actually deployed by iFR co-registration. The mean length of stents used by IFR co-registration was 20.2 mm stents (SD: 11.2 mm) and P-value was 0.0000.  Also, all patients needed stent via QCA while only 86% actually need stent application via iFR co-registration assessment, leading to a fewer stents placed per patient. The difference was statistically significant p<0.0022. This study demonstrates that iFR co-registration performed under resting conditions predicted the physiological outcome of PCI with a high degree of accuracy.  Compared with QCA, iFR co-registration significantly decreased the number and length of hemodynamically significant lesions identified for revascularization. iFR co-registration should be performed under resting Recommendation: iFR co-registration should be performed under resting conditions to predict the physiological outcome of PCI with a high degree of accuracy.