Mechanical thrombectomy for acute ischemic stroke with absent opacification of the cervical internal carotid artery at CT-angiography: pathophysiology and outcome

Abstract

Purpose Occlusion of distal internal carotid artery can simulate a proximal occlusion of its cervical tract at CT angiography in patients with acute ischemic stroke, i.e. pseudo-occlusion. As true and false carotid occlusions can have similar presentation at non-invasive imaging of a patient undergoing endovascular treatment for stroke, our study aimed to evaluate clinical and technical differences of these conditions and the possible consequences of a misdiagnosis. Methods We retrospectively reviewed consecutive patients who underwent mechanical thrombectomy for acute ischemic stroke in a single center between July 2015 and July 2021 and included patients with absent opacification of cervical carotid artery at CT-angiography. Digital subtraction angiography (DSA) imaging and procedural data were evaluated to define the actual localization of occlusion. We compared imaging and clinical data of patients with true and false carotid occlusion, including collateral circulation at CTA, revascularization grade and clinical outcome at 3 months. Results 95 patients were included, 52 (49%) had true occlusion of cervical internal carotid artery. Compared to the pseudo-occlusion group, collateral circulation at CTA was moderate to good in 67% of cases (vs 29%; p < 0.01) and mean ASPECT score at 24h was 5.5 vs 2.7 (p < 0.001). Modified Rankin scale 0–2 at 90 days was more frequent in patients with true occlusion compared to patients with pseudo-occlusion (44.9 vs 14.6%; p 0.003). Conclusion Pseudo-occlusion of cervical internal carotid artery in patients with acute ischemic stroke seem to be associated with worst prognosis and poorer collateral circulation.