External Iliac Artery Dissection Described on Duplex Ultrasonography.

This case involves a 73-year-old man with chronic limb-threatening ischemia who presented for a left lower extremity angiogram, which demonstrated high-grade stenosis of the distal superficial femoral artery and high-grade stenosis at the proximal anterior tibial artery with flow to the foot and collaterals to the posterior tibial (PT) artery. A long 7F sheath was only able to be advanced into the external iliac artery (EIA) during the procedure. Lesions were treated with balloon angioplasty and stent of the superficial femoral artery and angioplasty of the anterior tibial artery. The patient was asymptomatic after the operation; on examination, however, he did not have dorsalis pedis or PT signals, which were previously biphasic signals. An arterial duplex was performed that demonstrated concern for a dissection of the left EIA and no flow in the mid and distal PT artery. Duplex spectral waveform demonstrated an increased peak systolic velocity, corresponding to a rapid systolic upstroke followed by a systolic cleft and dome, and minimal diastolic flow (Fig. 1). The "spike and dome" waveform reflects a high-pressure flow consistent with dynamic obstruction from the dissection flap. This pattern contrasts with normal external iliac waveforms, which demonstrate a triphasic flow pattern. A heparin drip was started, and repeat left lower extremity angiogram demonstrated EIA dissection consistent with ultrasonography findings (Fig. 2). The distal EIA dissection was treated with an 8x5-cm Viabahn stent (Gore Medical) and dilated with a 7-mm balloon. Completion angiogram demonstrated resolution of the dissection and appropriate filling of the foot. Biphasic dorsalis pedis and PT signals were obtained postoperatively.