Clinical Validation of a Novel Pressure Microcatheter-Based Nonhyperemic Pressure Ratio (SUPREME II Study).

backgroundThe constant resistance ratio (cRR) is a novel nonhyperemic pressure ratio based on piezoresistive pressure microcatheter (PMC) measurements. With repeated measurements in randomized order of PMC and pressure wire techniques, this study aimed primarily to validate the diagnostic performance of cRR compared with fractional flow reserve (FFR) in coronary lesions of 30% to 90% diameter stenosis.

methodsSUPREME II (Sensor-Equipped Ultrathin Pressure Microcatheter Versus Pressure Wire for Physiological Measurements) was a multicenter, prospective study that included 466 patients (483 vessels) from 11 centers. All target vessels were assessed using both pressure wire and PMC separately in randomized order under resting and hyperemic conditions. The primary end point was the diagnostic accuracy of the cRR using a PMC-based FFR of ≤0.80 as the reference standard. Secondary end points included the cRR "gray zone" of the cRR-FFR hybrid strategy and the proportion of patients in whom diagnosed was achieved without vasodilator use.

resultsThe optimal cRR cutoff was 0.89, which correctly classified 82.8% of the patients, with a sensitivity and specificity of 87.0% and 80.1%, respectively, and achieved an area under the curve of 0.92 with FFR

conclusionsIn coronary stenosis of 30% to 90% diameter stenosis, cRR measurements were highly feasible. The diagnostic accuracy of cRR with FFR REGISTRATION: URL: https://clinicaltrials.gov/study/NCT05417763; Unique Identifier: NCT05417763.