394 AJR:186, February 2006 AJR 2006; 186:394–400 0361–803X/06/1862–394 © American Roentgen Ray Society M E D I C A L I M A G I N G A C E N T U R Y O F Grant et al. Sonography of Innominate Artery Occlusive Disease Vascular Imaging • Original Research Innominate Artery Occlusive Disease: Sonographic Findings Edward G. Grant 1 Suzie M. El-Saden 2 Beatrice L. Madrazo 3 J. Dennis Baker 4 Mark A. Kliewer 5 Grant EG, El-Saden SM, Madrazo BL, Baker JD, Kliewer MA Keywords: angiography, cardiovascular disease, Doppler sonography, innominate artery, subclavian steal syndrome DOI:10.2214/AJR.04.1000 Received June 25, 2004; accepted after revision January 24, 2005. 1 Department of Radiology, University of Southern California Keck School of Medicine, University Hospital, 1500 San Pablo St., Los Angeles, CA 90033. Address correspondence to E. G. Grant. 2 Department of Radiology, West Los Angeles VA Medical Center, Los Angeles, CA. 3 University of Miami Medical School, Miami, FL. 4 Department of Vascular Surgery, West Los Angeles VA Medical Center, Los Angeles, CA. 5 University of Wisconsin School of Medicine, Madison, WI. OBJECTIVE. The objective of this study was to report the sonographic abnormalities in a group of patients with angiographically proven innominate artery stenosis and occlusion. MATERIALS AND METHODS. A review of all cerebrovascular sonograms at our in- stitutions was undertaken to identify patients with complete or partial flow reversal in the right vertebral artery and reversal or midsystolic deceleration of flow in any one of the three major segments of the right carotid system (common, internal, or external carotid artery). The distri- bution and appearance of these abnormalities was evaluated, and the presence or absence of tar- dus-parvus waveforms was noted in any segment of the right carotid artery. Additionally, a left to right common carotid peak systolic velocity ratio (LCCA/RCCA) was calculated and com- pared to published normal values. All patients had correlative contrast or MR angiography. Correlation was made between the severity of stenosis as determined by angiographic images and waveform aberrations as well as the more objective LCCA/RCCA ratios. RESULTS. Twelve patients were identified as having the abnormalities described above in the right vertebral and carotid arteries. Doppler waveforms from the right vertebral artery revealed that eight of the 12 patients had complete reversal of flow at rest. Bidirectional flow was found in the remaining four as manifested by the presence of marked midsystolic deceleration. In the carotid arteries, one patient had complete reversal of flow in all segments of the right carotid sys- tem. Waveforms with midsystolic deceleration were identified in at least one of the carotid arteries of the remaining 11 patients: common carotid artery (8/11 = 73%), internal carotid artery (10/11 = 91%), external carotid artery (3/11 = 27%). The average LCCA/RCCA was 3.1 with a range of 1.7 to 5.7 (normal = 0.7–1.3). All patients had severe innominate artery disease (from 70% to occlusion) by contrast angiography or MR angiography. There was no correlation be- tween the angiographically determined degree of stenosis and the Doppler findings. CONCLUSION. A distinctive pattern of hemodynamic alterations occurs in the right ver- tebral and carotid arteries of patients with severe innominate artery disease. Findings include reversed or bidirectional flow in the right vertebral artery, the presence of midsystolic deceler- ation in any of the branches of the right carotid system, and elevated LCCA/RCCA ratio. tenosis or occlusion of the subcla- vian artery with subsequent sub- clavian steal syndrome is a well- recognized clinical entity [1]. The hallmark of subclavian steal is complete or par- tial reversal of flow in the ipsilateral vertebral artery in the neck [2]. Although these findings are relatively common in carotid sonography studies, most patients with this physiology are not symptomatic [3]. Stenosis or occlusion of the innominate artery is less common than sub- clavian obstruction and has received less atten- tion in the literature. In patients with signifi- cant innominate artery disease, blood flow to the arm is reconstituted by retrograde flow through the right vertebral artery, resulting in steal physiology similar to that seen with le- sions of the subclavian artery [4]. Unlike the hemodynamic alterations associated with sub- clavian lesions, however, innominate artery disease also affects the carotid circulation, put- ting patients at risk for both posterior fossa and hemispheric events (Fig. 1). The exact prevalence of innominate artery disease is difficult to determine, but reports indicate that hemodynamically significant le- sions are rare; in their study, Brunhölzl and von Reutern [5] identified only 20 cases among 30,000 patients. Older angiographic studies indicate that innominate artery lesions account for as many as 2.5–4% of atheroscle- rotic lesions of the extracranial and intracra- S Downloaded from www.ajronline.org by 52.73.204.196 on 05/16/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved