Predicting residual pressure gradients after balloon angioplasty in patients with femoropopliteal artery lesions.

In endovascular therapy (EVT) for femoropopliteal artery (FPA) lesions, studies examining the relationship between lesion morphology and hemodynamic status are limited. The purpose of this study was to investigate FPA lesion characteristics, including imaging findings and their cutoff values that can predict hemodynamic significance after balloon angioplasty. This single-center retrospective study enrolled 50 de novo FPA lesions from 43 patients treated under intravascular ultrasound (IVUS) usage between June 2022 and March 2023. As a physiological parameter, the pressure gradient was measured, and the cutoff value of the residual pressure gradient (RPG) was defined as a systolic pressure > 10 mmHg through the lesions after balloon angioplasty. The pressure gradients were measured using a 0.014-inch wire-guided, rapid exchange-type microcatheter, Navvus II (Acist, Eden Prairie, Minnesota, USA). Predictive risk factors for RPG were analyzed using the random forest (RF) method. The relationship between the variables, RPG, and the cutoff points of each predictor was assessed using the partial dependence plot (PDP) method. RPG was observed in 20% of the lesions after balloon angioplasty. The RF model revealed that the percent diameter stenosis (%DS) and minimum lumen area (MLA) on IVUS assessment were strong predictive factors for RPG after balloon angioplasty. The PDP model revealed that a higher %DS (cutoff 30%) and smaller MLA (cutoff 10 mm