Impact of "black rock" on clinical outcomes after endovascular therapy for de novo calcified femoropopliteal lesions

The relationship between severity of calcification and clinical outcomes after endovascular therapy (EVT) for femoropopliteal lesions is well known. We often encounter dense calcifications in our daily practice, which are darker than normal calcifications on angiography. Accordingly, we named it "black rock" (BR), and investigated its impact on clinical outcomes after EVT. We retrospectively analyzed 677 lesions in 495 patients who underwent EVT for de novo calcified femoropopliteal lesions at our hospital between April 2007 and June 2020. BR is defined as a calcification which is 1 cm or more in length, occupies more than half of the vessel diameter, and appears darker than the body of the femur on angiography. Propensity score matching analysis was performed to compare clinical outcomes between lesions with BR [BR (+) group] and without BR [BR (-) group]. A total of 119 matched pairs of lesions were analyzed. Primary patency at 2 years was significantly lower in the BR (+) group than in the BR (-) group (48% vs. 75%, p = .0007). Multivariate analysis revealed that the presence of BR [hazard ratio (HR) = 2.23, 95% confidence interval (CI); 1.48-3.38, p = .0001], lesion length (HR = 1.03, 95%CI; 1.00-1.06, p = .0244), and no scaffold use (HR = 1.58, 95%CI; 1.06-2.36, p = .0246) were predictors of restenosis. The presence of BR is independently associated with clinical outcomes after EVT for de novo calcified femoropopliteal lesions.