Importance of Delayed Reperfusions in Patients With Incomplete Thrombectomy

Abstract

Background: There is paucity of data regarding the effects of delayed reperfusion (DR) on clinical outcomes in patients with incomplete reperfusion following mechanical thrombectomy. We hypothesized that DR has a strong association with clinical outcome in patients with incomplete reperfusion after mechanical thrombectomy (expanded Thrombolysis in Cerebral Infarction, 2a-2c).

Methods: Single-institution's stroke registry retrospective analysis of patients admitted from February 2015 to December 2020. DR was defined as the absence of any perfusion delay on ≈24-hour contrast-enhanced follow-up perfusion imaging, whereas persistent perfusion deficit denotes a perfusion delay corresponding to the catheter angiographic deficit directly after the intervention. The association of perfusion outcome (DR versus persistent perfusion deficit) with the occurrence of new infarcts and 90-day functional independence (modified Rankin Scale score 0-2) was evaluated using logistic regression analyses. Comparison of predictive accuracy was evaluated by calculating area under the curve for models with and without perfusion outcome.

Results: In 566 patients (mean age 74, 49.6% female), new infarcts in the incomplete reperfusion areas were less common in DR versus persistent perfusion deficit patients (small punctiform: 17.1% versus 25%, large confluent: 7.9% versus 63.2%; P=0.001). After adjustment for confounders, DR was a strong predictor of functional independence (adjusted odds ratio, 2.37 [95% CI 1.34-4.23]). There was a significant improvement in predictive accuracy of functional independence when perfusion outcome was added to expanded Thrombolysis in Cerebral Infarction alone (area under the curve 0.57 versus 0.62, P=0.01).

Conclusions: Occurrence of DR is closely associated with tissue outcome and functional independence. DR may be an independent prognostic parameter, suggesting it as a potential outcome surrogate for medical rescue therapies.

Keywords: ischemic stroke; magnetic resonance imaging; reperfusion; thrombectomy; tomography.

Figure 1.

Delayed reperfusion and persistent perfusion deficit on perfusion follow-up imaging. Time to maximum (Tmax) and diffusion-weighted imaging (DWI) imaging maps were evaluated on admission and follow-up examinations. Final angiography runs are displayed with high contrast to emphasize the capillary phase deficits. A, Patient with a right side M1 occlusion with delayed reperfusion on magnetic resonance imaging (MRI) follow-up after expanded Thrombolysis in Cerebral Infarction (eTICI) 2b50 reperfusion, together with corresponding admission DWI (top-left), admission perfusion imaging (bottom-left), final angiography imaging (middle), follow-up DWI (top-right), follow-up perfusion imaging (bottom-right). B, Patient with a left side M2 occlusion with delayed reperfusion on MRI follow-up after eTICI 2b67 reperfusion, together with corresponding admission CT imaging (top-left), admission perfusion imaging (bottom-left), final angiography imaging (middle), follow-up DWI (top-right), follow-up perfusion imaging (bottom-right). C, Patient with a right side M1 occlusion with persistent perfusion deficit and confluent infarct on MRI follow-up after eTICI 2b50 reperfusion together with corresponding admission DWI (top-left), admission perfusion imaging (bottom-left), final angiography imaging (middle), follow-up DWI (top-right), follow-up perfusion imaging (bottom-right). D, Patient with a right side M1 occlusion with persistent perfusion deficit and punctiform-infarct on MRI follow-up after eTICI 2b67 reperfusion together with corresponding admission DWI (top-left), admission perfusion imaging (bottom-left), final angiography imaging (middle), follow-up DWI (top-right), and follow-up perfusion imaging (bottom-right).

Figure 2.

Clinical impact of delayed reperfusion. A, Better reperfusion rates across the expanded Thrombolysis in Cerebral Infarction (eTICI) spectrum were associated with better functional independence. B, There was better outcome among patients with delayed reperfusion (DR) of any eTICI grade as opposed to patients with persistent perfusion deficit (PPD) of any eTICI grade, eg, better outcome of eTICI 2b50 with DR than eTICI 2c with PPD.

Figure 3.

Predictor accuracy for favorable clinical outcome. A, Unadjusted regression model for only expanded Thrombolysis in Cerebral Infarction (eTICI; red) and eTICI with perfusion outcome (blue) showed significant effect of perfusion outcome on clinical outcome (area under the curve [AUC], 0.57 [95% CI, 0.52–0.63] vs AUC 0.62 [95% CI, 0.56–0.68], respectively; P=0.01). B, Multivariable logistic regression models adjusted to age, sex, National Institutes of Health Stroke Scale on admission, onset-to-door time, intravenous thrombolysis, collateral status, occlusion site, Alberta Stroke Program Early CT Score, and eTICI (colored in red, see Methods). Aside from the aforementioned, perfusion outcome was added as an additional variable to the comparator model (blue). There was no statistical significance between the 2 models (AUC, 0.77 [95% CI‚ 0.73–0. 82] vs AUC, 0.79 [95% CI‚ 0.74–0.83], respectively; P=0.15).