Peak Systolic Velocity Ratio Cutoffs for Diagnosing Hemodynamically Significant Iliac Artery Stenosis: A Systematic Review and Evidence Gap Analysis

Peak systolic velocity ratio (PSVR) measured by duplex ultrasound has not been systematically compared against a physiologic reference standard. This systematic review and evidence gap analysis aimed to assess studies evaluating the validity of PSVR cut-offs in identifying hemodynamically significant iliac artery stenosis versus hyperemic intra-arterial (IA) pressure gradients. Five prospective studies with a total of 254 patients and 278 iliac artery segments from European vascular centers were identified in a comprehensive search of 7 databases from inception through August 6, 2025, with no language restriction. The heterogeneous hyperemic stimuli (papaverine, nitroglycerin, exercise) and heterogeneous reference thresholds were used in the studies and prevented pooling; hence, they were analyzed as four distinct target condition groups (Group A: ≥10 mmHg absolute; Group B: composite ≥20 mmHg/≥15% femoral-brachial index (FBI); Group C: ≥18% relative gradient; Group D: arteriographic). Using the most tested PSVR ≥ 2.5, sensitivity was 37%-83%, and specificity was 67%-93% between Groups A and B alone. Absolute PSV increase (DPSVe) ≥ 1.4 m/s after exercise was found to have 93% sensitivity and 87% specificity in the borderline-stenosis group. None of the studies had confidence intervals (CI). A structured sensitivity/specificity tabulation was used in the absence of reconstructable 2 x 2 data as a substitute for visual synthesis; formal meta-analysis was not possible. The quality of evidence was very low using the GRADE method. The main value of this review is to show that there is very limited and low-certainty evidence supporting physiologically validated PSVR thresholds; PSVR ≥ 2.5 should be considered an expert practice standard, rather than a validated diagnostic criterion.