Collateral vessel size and number could predict severe dissection after balloon angioplasty in patients with femoropopliteal artery chronic total occlusion.

Objective: Collateral vessels develop from pre-existing arterioles in response to shear stress from arterial stenosis and mechanosensor activation. Animal studies suggest that these vessels increase in number and size after arterial occlusion, potentially offering a natural bypass and protection against critical limb ischemia. Efforts to enhance collateral vessel growth aim to improve walking performance in peripheral arterial disease (PAD). Factors influencing collateral vessel formation include plaque accumulation, tissue components, and comorbid conditions. Balloon angioplasty is a primary treatment for PAD but often leads to vessel dissection, with severe dissections linked to reduced long-term patency and requiring additional treatments. The relationship between collateral vessel characteristics and dissection severity remains unexplored.

Materials and methods: This retrospective study analyzed endovascular treatments for femoropopliteal chronic total occlusion (FP-CTO) in 824 limbs of 706 PAD patients from January 2018 to May 2023. Exclusion criteria included prior treatments, severe aortoiliac and common femoral artery disease, and deep femoral artery disease. The final cohort comprised 410 limbs from 387 patients. Data on risk factors, lesion characteristics, and procedural details were collected. Collateral vessels were assessed by grade and number, and vessel dissection was categorized from Type A to Type F. Multivariate logistic regression identified predictors of severe dissection.

Results: Severe dissection was more frequent in TASC II C/D lesions and in patients with longer FP-CTO lengths, CTOP class-4 plaque morphology, flush ostial CTO, severe calcification, and large or numerous collateral vessels. Significant predictors of severe dissection included end-stage renal disease, FP-CTO length, CTOP class-4, flush ostial CTO, severe calcification, and large collateral vessels.

Conclusion: Longer CTO lengths and complex plaque characteristics increase the risk of severe dissection during balloon angioplasty. Large and numerous collateral vessels are associated with severe dissection. Severe dissection is more common in complex lesions and those with end-stage renal disease. The findings suggest that plaque compliance and collateral vessel characteristics are crucial in assessing dissection risk, highlighting the need for further research with larger cohorts and advanced imaging techniques.