String-like lumen in below-the-knee chronic total occlusions on contrast-enhanced magnetic resonance angiography predicts intraluminal recanalization and better blood flow restoration.

Objectives: To determine whether string-like lumina (SLs) on contrast-enhanced magnetic resonance angiography (CE-MRA) predict better outcomes in diabetic patients with below-the-knee (BTK) chronic total occlusions (CTOs).

Methods: This study involved 317 long-segment (>5 cm) BTK CTOs of 245 patients that were examined using CE-MRA and treated using endovascular angioplasty. An SL with a CTO was slowly filled with blood on conventional CE-MRA. Univariate and multivariate analyses were performed to identify predictors of procedural success, recanalisation method and immediate blood flow restoration. The target-lesion patency and limb-salvage rates were assessed.

Results: SL-positive CTOs (n = 60) achieved a higher technique success rate, preferred intraluminal angioplasty and better blood flow restoration than SL-negative CTOs (n = 257, P < 0.05). Multivariate analyses revealed that lesion length was the independent predictor of procedural success (P = 0.028). SL was a predictor of intraluminal angioplasty (P < 0.001) and good blood-flow restoration (P = 0.004). Kaplan-Meier analyses at 12 months revealed a higher target lesion patency rate (P = 0.04) and limb-salvage rate (P = 0.35) in SL-positive CTOs.

Conclusions: In patients with BTK CTOs, SL predicted intraluminal angioplasty and good blood-flow restoration for BTK CTOs.

Key Points: • Intraluminal recanalisation was more frequently used for BTK-CTOs with SLs than without • CTO length was the only independent predictor of successful CTO recanalisation • SL was the only predictor of intraluminal angioplasty for BTK-CTOs • SL and CTO length were predictors of good blood-flow restoration after recanalisation • Restenosis-free and limb-salvage rates were better for SL-positive CTOs than SL-negative CTOs.