DOT sign indicates persistent hypoperfusion and poor outcome in patients with incomplete reperfusion following thrombectomy

Background Distal occlusions associated with incomplete reperfusion (expanded Thrombolysis in Cerebral Infarction, <eTICI 3) may not reperfuse spontaneously and thus prompt ischemia (ie, persistent hypoperfusion). We aimed to assess whether the recently reported Distal Occlusion Tracker (DOT) sign on immediate non-contrast post-interventional flat-panel detector computed tomography (FPDCT) is associated with persistent hypoperfusion. Methods Retrospective registry analysis of patients undergoing endovascular therapy between July 2020 and December 2022, with available immediate post-interventional FPDCT and 24 hours follow-up perfusion imaging. Persistent hypoperfusion was defined as a perfusion deficit at 24 hours directly corresponding to the area of incomplete reperfusion on final angiography run. The DOT sign was defined as a punctiform or tubular hyperdense signal increase on FPDCT indicative of a residual occlusion. Association between the DOT sign (present/absent) with the occurrence of persistent hypoperfusion and poor outcome (modified Rankin scale (mRS) score 3–6) was evaluated using logistic regression analysis. Results Of 292 patients included (median age 73 years; 47% female), 209 had incomplete reperfusion. Among patients with incomplete reperfusion, 61% had a present DOT sign and 46% had persistent hypoperfusion. In the overall cohort, but also within each eTICI stratum, a present DOT sign was associated with persistent hypoperfusion on 24±12 hours follow-up perfusion imaging (adjusted odds ratio (aOR) 4.8, 95% confidence interval (CI) 2.0 to 12.3 for patients with eTICI 2 a-2c). A present DOT sign was also associated with poor outcome (aOR 2.6, 95% CI 1.1 to 6.2). Conclusion Patients with <eTICI 3 and a present DOT sign have a higher likelihood of persistent hypoperfusion and might constitute a subgroup that could particularly benefit from additional reperfusion attempts.