Impact of Plaque Calcification and Stent Oversizing on Clinical Outcomes of Atherosclerotic Femoropopliteal Arterial Occlusive Disease Following Stent Angioplasty

Objective: Plaque calcification and stent oversizing are two key factors contributing to in stent restenosis (ISR) following femoropopliteal stent angioplasty. This study aimed to explore a pre-operative quantitative assessment method of plaque calcification and rational parameters of stent oversizing in the femoropopliteal artery. Methods: A total of 115 patients with atherosclerotic femoropopliteal arterial occlusive disease treated from January 2013 to January 2016 were included retrospectively. Computed tomography angiography (CTA) imaging was performed to analyse calcified plaque parameters (calcified plaque volume [CV], standard CV [SCV], burden of calcified plaque) and stent oversizing parameters at different vessel segments (distal oversizing, maximum oversizing, plaque oversizing). Optimal cut offs for the six parameters were determined by the maximum Youden's index. The relationship between calcified plaque, stent oversizing, and clinical outcomes were assessed by correlation analysis and multivariable Cox regression models. Results: The one year primary patency rate was 77.4%; the rates of ISR, major amputation, target lesion revascularisation, and mortality were 40.9%, 8.7%, 17.4%, and 12.2%, respectively. For all six parameters, patients with values greater than the cut offs had a significantly higher incidence of ISR than those with values below the cut offs. ISR was positively correlated with all six calcification and oversizing parameters. Amputation and mortality were positively correlated with calcification parameters. Multivariable Cox regression analysis demonstrated that all six parameters were independent risk factors for ISR. All calcification parameters were identified as independent risk factors for amputation, while only CV and SCV were independent risk factors for mortality. Conclusion: Calcified plaque in the femoropopliteal artery can be quantitatively analysed on pre-operative CTA images. High calcified plaque burden and excessive stent oversizing were associated with unfavourable outcomes following stent angioplasty.