Influence of a Novel Morphology-Driven Classification on Limb Salvage After Tibial Intervention for Limb-Threatening Critical Ischemia

Abstract

Infrapopliteal interventions for limb-threatening critical ischemia can be affected by the morphology of the tibial vessels. The aim of this study was to examine the impact of a novel morphology-driven classification on the outcomes of endovascular intervention for limb-threatening critical ischemia. A database of patients undergoing lower extremity endovascular interventions between 2007 and 2017 was retrospectively queried. Patients with isolated infrapopliteal disease were identified, and their anatomy was scored by lesion calcification, target vessel diameter <3.0 mm, lesion length >300 mm, and poor pedal runoff score. Patients were then divided into three groups with 0 or 1 (low risk), 2 (moderate risk), and 3 or 4 (high risk) factors. Intention-to-treat analysis by patient was performed. Outcomes were then assessed for amputation-free survival and freedom from major adverse limb events (MALEs). Anatomic predictors and risk stratification for MALEs were analyzed by Cox proportional hazard analysis. There were 1334 patients (55% male; average age, 60 years; 2134 vessels) who underwent tibial intervention for limb-threatening critical ischemia. The average Edifoligide for the Prevention of Vein Graft Failure in Lower Extremity Bypass Surgery—Phase III Trial (PREVENT III) amputation risk score (PIII score) was 4.5 ± 1.6 (mean ± standard deviation), with 13% considered high risk overall. Technical success was 96%. Overall major adverse cardiovascular event rate was 3% and MALE rate was 19% at 30 days. Major amputation rate was 11% at 30 days. At 5 years, overall cardiac event rate was 41% ± 4% (mean ± standard error of the mean); overall amputation-free survival, 34% ± 3%; and overall MALE rate, 45% ± 4%. When stratified by morphology, those patients with high-risk morphology had worse short-term and long-term outcomes (Table).TableOutcomes of endovascular tibial intervention stratified by morphologyLow riskModerate riskHigh riskNo. of limbs at risk240507587No. of vessels598918619High-risk PIII score35a8b30-Day MACE12330-Day MALE418a45b30-Day amputation rate81233a5-Year CE, mean ± SEM58 ± 540 ± 6a23 ± 9 b,c5-Year AFS, mean ± SEM55 ± 537 ± 6a18 ± 7b,c5-Year MALE, mean ± SEM60 ± 546 ± 5a22 ± 9b,dAFS, Amputation-free survival; CE, cardiac event; MACE, major adverse cardiovascular event; MALE, major adverse limb event; PIII, Edifoligide for the Prevention of Vein Graft Failure in Lower Extremity Bypass Surgery—Phase III Trial (PREVENT III); SEM, standard error of the mean.Values are reported as percentage unless otherwise indicated.aP < .05 compared with low risk.bP < .01 compared with low risk.cP < .05 compared with moderate risk.dP < .01 compared with moderate risk. Open table in a new tab AFS, Amputation-free survival; CE, cardiac event; MACE, major adverse cardiovascular event; MALE, major adverse limb event; PIII, Edifoligide for the Prevention of Vein Graft Failure in Lower Extremity Bypass Surgery—Phase III Trial (PREVENT III); SEM, standard error of the mean. Values are reported as percentage unless otherwise indicated. aP < .05 compared with low risk. bP < .01 compared with low risk. cP < .05 compared with moderate risk. dP < .01 compared with moderate risk. Anatomic morphology affects isolated endovascular tibial intervention, with adverse morphology associated with poorer short- and long-term outcomes. Risk stratification based on anatomic predictors should be considered as one intervenes on infrapopliteal vessels for limb-threatening critical ischemia.