Semiquantitative assessment of tibial artery calcification by computed tomography angiography and its ability to predict infrapopliteal angioplasty outcomes

Abstract

Tibial artery calcification (TAC) is associated with increased risk of amputation and mortality in peripheral artery disease. We sought to investigate whether the severity of TAC based on semiquantitative analysis of computed tomography angiography (CTA) can predict outcomes of endovascular therapy in patients with critical limb ischemia. We reviewed medical records of 124 patients who underwent lower extremity CTA before intervention. Based on CTA, TAC severity was categorized into three groups: minimal calcification (MC; n= 43), intermediate calcification (IC;n= 36), or extensive calcification (EC; n= 45). Immediate and late outcomes of infrapopliteal interventions were compared, and predictors of the outcomes were investigated. The categorized severity of target TAC correlated with the log-transformed TAC score (r= 0.873; P< .001). The EC group was younger and had more diabetes and chronic kidney disease compared with the MC or IC group (all P< .001). The technical success was lower in the EC group (71.1%) than in the MC (95.3%) or IC (91.7%) group (P= .001). The survival free of unplanned amputations at 2years was significantly lower in the EC group (58.9%) than in the MC (79.0%) or IC (95.3%) group (P< .001). Extensive TAC was an independent predictor of technical success (hazard ratio, 0.02; 95%confidence interval, 0.00-0.45; P= .014) and unplanned amputation (hazard ratio, 9.90; 95% confidence interval, 2.05-47.75; P= .004). The categorized severity of TAC by semiquantitative analysis of CTA correlated with TAC score, and extensive TAC was associated with a lower technical success rate of angioplasty and an increased incidence of unplanned amputation.