Rupture of a peripheral popliteal artery plaque documented by intravascular ultrasound: a case report.

A 58-year-old male with dyslipidemia and coronary spastic angina suddenly experienced pain in the right limb while walking on November 1, 2008. Right-ankle brachial pressure index (ABI) was decreased (0.80) and left-ABI was normal (1.24). Bilateral ABI was normal during January 2008. Ultrasonography in the right-lower limb artery revealed severe stenosis in the right-popliteal artery with extended and large echolucent plaques containing an isoechoic area. We carried out lower limb angiography: subtotal occlusion of the popliteal artery was found. By intravascular ultrasound (IVUS), right-popliteal artery plaques were echolucent and eccentric; ulceration with a thin fibrous cap was noted. Percutaneous transluminal angioplasty was done and popliteal artery blood flow was improved. Right-ABI improved to 1.13 after 4 days. To prevent the progression and rupture of the plaques, lipid-lowering therapy and antiplatelet therapy were started. Plaque rupture of the popliteal artery was diagnosed by these characteristics on IVUS. Patients with peripheral artery disease may have plaque rupture similar to those with acute coronary syndromes who have identical unstable plaques and unstable atheromas. In addition to appropriate local revascularization, systemic therapy to stabilize the unstable plaque is indicated because failure to do so may cause recurrent events.