Fate of collateral vessels following subintimal angioplasty

Purpose: To evaluate the fate of collateral vessels adjacent to and within the target lesion following subintimal angioplasty (SIA). Methods: Pre and postprocedural angiograms were reviewed for 29 patients undergoing SIA of the lower extremity arteries over a 3-year period. The number of patent collateral vessels ≤5 cm proximal to the occlusion (proximal segment) and ≤5 cm distal to the occlusion (distal segment) were recorded pre and postprocedurally and compared. In addition, the number of collateral vessels that were re-opened within the recanalized segment following SIA was counted. Results: The mean number of patent collaterals in the proximal segment was 1.9 (range 0-4) preprocedurally and 1.4 (range 0-4) postprocedurally (p<0.002). The mean number of patent collaterals in the distal segment was 1.9 (range 0-4) pre-procedurally and 1.0 (range 0-4) postprocedurally (p<0.0001). Previously absent collaterals within the recanalized segment were observed in 4 (14%) of 29 patients post-SIA. The mean number of collateral vessels within all 3 segments (proximal, treated, and distal) was 3.9 collaterals preprocedurally and 2.9 collaterals postprocedurally Conclusions: Some collateral vessels are sacrificed during SIA, but the majority are preserved. In addition, SIA has the potential to open new collaterals within the occluded segment. These collaterals may play an important role should restenosis develop within the target segment.