Corkscrew collaterals in atherosclerosis obliterans.

Marked calcifications in the femoral artery obscured imaging of the artery in computed tomography (CT) and duplex ultrasonography. The presence of corkscrew collateral arteries in patients with Atherosclerosis obliterans (ASO) indicates total artery occlusion.

Introduction

Atherosclerosis obliterans (ASO) is a major cause of peripheral artery disease; revascularization is performed if the results of arterial imaging deem it feasible. Angiography is the gold standard of vascular imaging; however, it is an invasive procedure. Contrast computed tomography (CT) or duplex ultrasonography can also be performed, but severe calcification can cause artifacts, confounding a determination of arterial patency.

Case Report

We describe a 73‐year‐old man who presented with symptoms of intermittent claudication and diabetes mellitus. The ankle‐brachial index was low on the right side, and he was diagnosed with ASO. Early treatments, including the administration of both aspirin and sarpogrelate, did not improve his symptoms; thus, we considered angioplasty. Plane CT showed marked calcifications in the femoral artery (Fig. 1A); these artifacts obscured imaging of the femoral artery with the contrast agent. Color duplex ultrasonography also showed marked calcifications and acoustic shadow (Fig. 1B); these artifacts obscured imaging of the artery. After rotating the ultrasound probe at the same level, a corkscrew collateral artery was visible as dot sign (Fig. 2). Digital subtraction angiography showed occlusion of the femoral artery, with corkscrew collateral arteries in the femoral region (Fig. 3). The patient underwent peripheral angioplasty, and his symptoms improved.

Figure 1

Computed tomography showing marked calcifications in the femoral artery (arrow, panel A). Color duplex ultrasonography showing marked calcifications and acoustic shadow (panel B). These artifacts obscured imaging of the artery.

Figure 2

Corkscrew collateral arteries were visualized by color duplex ultrasonography.

Figure 3

Digital subtraction angiography showing occlusion of femoral artery (black arrow), with corkscrew collateral arteries (red arrow).

Discussion

Duplex ultrasonography and CT angiography have high specificities and sensitivities in detecting a stenosis or an occlusion 1. However, marked calcifications in the femoral artery obscured imaging of the artery.

After occlusion of main artery, the gradient between proximal and distal pressures recruits the growth of collateral arteries (arteriogenesis) 2. Existence of collateral arteries indirectly indicates main artery occlusion. Recently, color duplex ultrasonography has been used to clarify the sign of corkscrew collaterals 3, 4. The presence of corkscrew collateral arteries in patients with ASO indicates total artery occlusion.

Conclusion

We report an atherosclerotic case with intermittent claudication. Severe calcification can cause artifacts, confounding a determination of arterial patency. Existence of corkscrew collateral artery indicates that the patient is ASO with total artery occlusion.

Authorship

YF and HT: drafted the article and performed conception of this study. YF and TU: involved in performing the angiography. HT: performed percutaneous transluminal angioplasty. YU: involved in performing the duplex ultrasonography. YF: contributed to revising the article critically for important intellectual content.

Conflict of Interest

None declared.