Classification of corkscrew collaterals in thromboangiitis obliterans (Buerger's disease): relationship between corkscrew type and prevalence of ischemic ulcers.

BACKGROUND

A corkscrew collateral appearance on angiography is one of the diagnostic criteria for Buerger's disease. The purpose of the present study was to classify the angiographic findings of corkscrew collaterals and to evaluate the relationship between corkscrew collateral type and the severity of Buerger's disease.

METHODS AND RESULTS

Corkscrew collaterals were assessed on digital subtraction angiography in lower extremities of 28 patients with Buerger's disease (55 limbs). The corkscrew sign was classified into 4 types by size and pattern as follows: type I, artery diameter >2 mm, large helical sign; type II, diameter >1.5 mm and <or=2 mm, medium helical sign; type III, diameter >or=1 mm and <or=1.5 mm, small helical sign; and type IV, diameter <1 mm, tiny helical sign. The prevalence of ischemic ulcers was significantly higher in patients with types III and IV corkscrew collaterals than in patients with types I and II corkscrew collaterals either below or above the knee. Multiple regression analysis indicated that types III and IV below the knee are independent predictors of risk of ischemic ulcers.

CONCLUSIONS

The prevalence of ischemic ulcers is significantly higher in patients who have small corkscrew patterns in distal segments of limb collaterals than in patients who have large corkscrew collaterals.