Carotid Duplex Findings in Patients with Acute Type A Dissection

OBJECTIVES: Ten percent of patients with acute Type A dissection present with neurologic deficit. Initial workup may include a carotid duplex scan. This retrospective study was performed to determine the sensitivity of carotid duplex in diagnosing acute type A dissection.
METHODS: Between September 1999 and October 2008, 241 consecutive patients presented with acute type A aortic dissection. Retrospective chart review identified fifty-four patients who had carotid duplex exams hospitalization. Two patients were excluded because images were not available. Carotid duplex studies were reviewed by three independent reviewers. Abnormalities on duplex included: dissection flap, reversal of flow in the false lumen, high resistance spectral waveforms patterns--typical of the external carotid artery, noted in the common and internal carotid arteries without evidence of distal disease, and multiple systolic peaks in the common carotid artery waveform.
RESULTS: 45 (87%) had abnormal waveforms consistent with Type A dissection. Left common carotid artery waveform was abnormal in 40 patients (78%). Dissection flap extending into the carotid arteries was uncommon. No patient had a high-grade stenosis or occlusion of the internal carotid artery. 8 patients (15%) patients presented with stroke (4) or TIA (4) pre-operatively. Four (8%) patients developed stroke post-operatively. All patients presenting with or developing neurologic deficit demonstrated abnormal flow.
CONCLUSIONS: Acute type A dissection may present with stroke or transient ischemic attack. This is the first time that an abnormal waveform in the carotid artery diagnostic of acute type A dissection has been described. Importantly, this waveform was present more often than a dissection flap extending into the great vessels. Physicians and sonographers performing vascular lab studies should be aware of this critical information.