Abstract P546: Emergent Carotid Artery Stenting and Intracranial Thrombectomy for Acute Stroke With Tandem Occlusion

Introduction: Safety of emergent carotid artery stenting (CAS) during endovascular thrombectomy (EVT) for acute strokes with intracranial large vessel and cervical internal carotid artery tandem occlusion is still unclear. Given the potential risk of symptomatic intracranial hemorrhage (ICH) with anti-thrombotic medications required in the setting of CAS, the decision between CAS versus carotid artery angioplasty (CAA) alone remains controversial. In this study, we aimed to identify the optimal endovascular carotid revascularization approach in this patient population, using a large, nationally representative dataset.

Methods: We utilized the Nationwide Readmissions Database 2016-2017 to identify patients admitted due to acute ischemic stroke who underwent anterior circulation EVT as well as CAS or CAA on the same day. Survey design methods were used to generate national estimates. Logistic regression analysis was used to compare the in-hospital outcomes between patients who underwent CAS versus CAA. Survival analysis was used to estimate the 30-day readmissions.

Results: We identified 2,042 hospitalizations meeting the study inclusion criteria (mean±SD age: 66.0±12.5 years, female 31.3%). Of these, 1,391 (68.1%) had undergone CAS and 651 (31.9%) CAA alone. Baseline characteristics between the two groups were similar except patients with CAS were more likely to be on anti-thrombotics and were less likely to have received intravenous thrombolysis (tPA) as compared to those with CAA. There was no significant difference in the clinical outcomes including ICH, in-hospital mortality, gastrostomy tube placement, prolonged mechanical ventilation, length of stay, and hospital charges between the two groups in unadjusted analysis and after adjustment for the demographics and tPA use. All-cause 30-day readmission rate was similar between the two groups [hazards ratio (HR) 0.98, 95% confidence interval (CI) 0.64-1.51, p-value 0.924]. Patients with CAS had more readmissions due to ICH (HR 2.72, 95% CI 0.30-24.74) and less readmissions due to ischemic events (HR 0.78, 95% CI 0.12-5.08), although the difference was not statistically significant.

Conclusion: Emergent CAS-EVT approach appears to be safe with no adverse outcomes compared to CAA alone.

Abstract P553: Outcomes of Acute Endovascular Cervical Carotid Revascularization in Anterior Circulation Tandem Occlusions During Mechanical Thrombectomy

Introduction: Acute ischemic strokes with intracranial large vessel occlusion (LVO) and cervical internal carotid artery (ICA) tandem occlusion have traditionally been known to have a poor prognosis. Recent evidence suggests favorable functional outcomes in patients undergoing emergent carotid artery stenting (CAS) following intracranial mechanical thrombectomy (MT). We aimed to evaluate the outcomes of endovascular carotid revascularization (CR) performed acutely after emergent intracranial MT.

Methods: We used the Nationwide Readmissions Database 2016-2017 to identify patients admitted with anterior circulation LVO treated with MT. Patients who underwent CAS or carotid artery angioplasty (CAA) during the same hospitalization were also identified. Propensity scores were used to match patients with and without CR in a 1:1 ratio by demographics, comorbidities, use of intravenous thrombolysis and hospital-level characteristics. Logistic regression and survival analyses were used to compare the outcomes.

Results: We identified 15,137 hospitalizations meeting the study inclusion criteria (mean±SD age:70.1±14.6, female 51.1%). Of these, 1,214 (8.0%) underwent CAS or CAA during the same hospitalization. After propensity score matching, we obtained 1,063 well matched pairs of patients with and without CR. In the matched cohort, patients who underwent CR had higher odds of hemorrhagic transformation (OR 1.34, 95% CI 1.07-1.69, p 0.011) and higher total hospital cost (mean difference $6,232, 95% CI 3,606-8,858, p 0.001) but other clinical outcomes including gastrostomy tube placement, decompressive craniectomy, prolonged mechanical ventilation, in-hospital mortality, length of stay, and discharge disposition did not differ between the two groups. Patients with CR were less likely to have an unplanned 30-day readmission (HR 0.67, 95% CI 0.51-0.87, p 0.004). Further, they had more readmissions due to ICH (HR 1.06, 95% CI 0.41-2.71) and less readmissions due to ischemic events (HR 0.39, 95% CI 0.14-1.08), although the difference was not statistically significant.

Conclusion: If indicated, early endovascular CR for anterior circulation tandem occlusions seems to be safe with clinical outcomes comparable to patients undergoing MT alone.

Abstract MP33: Association Between Neurologic Outcomes and Temporal Profile of Systolic Blood Pressure Variability After Endovascular Thrombectomy

Introduction: Higher systolic blood pressure variability (BPV) after endovascular thrombectomy (EVT) has been associated with an increased risk of hemorrhagic transformation and worse functional outcomes. However, the time-varying behavior of BPV after EVT and its effects on functional outcome have not been well characterized.

Methods: We analyzed data from an international cohort of patients with acute large-vessel occlusion stroke who underwent EVT at 11 centers across North America, Europe, and Asia. Repeated time-stamped blood pressure data were recorded for the first 72 hours after thrombectomy. Parameters of BPV were calculated in 12-hour epochs using five established methodologies: standard deviation (SD), coefficient of variation (CV), average real variability (ARV), successive variation (SV), and residual SD (rSD). Patients’ overall mean BPV was then used to assign patients into tertiles for regression analysis: low BPV, intermediate BPV, and high BPV. Functional outcome was measured with the modified Rankin Scale (mRS) at 90 days.

Results: Of the 1,791 patients (age 69 ± 14, NIHSS 15 ± 6) included in our analysis, 1,085 (60.6%) had a poor 90-day outcome (mRS >3). Patients with poor outcome had significantly higher systolic BPV (p<0.05) measured as standard deviation (SBP SD) at each epoch (Figure 1B). Compared to patients with low BPV, those in the highest tertile group had significantly greater odds of a poor functional outcome after adjusting for age, sex, hypertension, NIHSS, ASPECT, tPA, time to reperfusion, and TICI score (OR 1.5; 95% CI 1.2-2; p=0.001). Patients in the highest tertile of BPV demonstrated time-dependent variability with the highest SBP SD during the first 24 hours after thrombectomy (Figure 1A).

Conclusions: Higher BPV measured by SBP SD appears to be associated with poor 90-day outcome in EVT-treated stroke patients. Early treatment strategies targeting early high BPV warrant further prospective investigation.

Retrieval of distally migrated coil using stent retriever and proximal aspiration

Endovascular coiling has become the preferred treatment of many centers for the management of both ruptured and unruptured aneurysms. Coil migration is a rare complication that can lead to vessel occlusion in 90% of the cases. Endovascular techniques for coil retrieval have shown less complication rates than open surgery. Stent retriever devices have been successfully used for the retrieval of proximally migrated coils, however, distally migrated coils still represent a challenge with greater risk of complications. In the present technical video 1, we demonstrate the successful retrieval of a distally M3 migrated coil using a 3 mm Trevo XP ProVue stent riever (Stryker Neurovascular, Fremont, CA, USA) in combination with proximal aspiration. neurintsurg;13/9/860/V1F1V1Video 1.

Combined Transradial and Transfemoral Approach With Ostial Vertebral Balloon Protection for the Treatment of Patients With Subclavian Steal Syndrome

Background: Patients with an obstructive subclavian artery (SA) may exhibit symptoms of vertebrobasilar insufficiency known as subclavian steal syndrome (SSS). Endovascular treatment with stent assisted percutaneous transluminal angioplasty (SAPTA) demonstrates significantly lower percentage of intraoperative and postoperative complications in comparison with open surgery. There is a 1–5% risk of distal intracranial embolization through the ipsilateral vertebral artery (VA) during SAPTA.

Objective: To assess the safety and feasibility of a novel technique for distal embolic protection using balloon catheters during SA revascularization with a dual transfemoral and transradial access.

Methods: We describe a case series of patients with SSS who underwent SAPTA due to severe stenosis or occlusion of the SA using a combined anterograde/retrograde approach. Transfemoral access to SA was obtained using large bore guide sheaths. Ipsilateral transradial access was obtained using intermediate bore catheters. A Scepter XC balloon catheter was introduced through the transradial intermediate catheter into the ipsilateral VA at the ostium during SAPTA for distal embolic protection.

Results: A total of eight patients with SSS underwent subclavian SAPTA. Four patients had the combined anterograde/retrograde approach. Successful revascularization was achieved in three of them. It was difficult to create a channel in the fourth unsuccessful case due to heavily calcified plaque burden. No peri-operative ischemic events were identified. On follow-up, we demonstrated patency of the stents with resolution of symptoms and without any adverse events.

Conclusion: Subclavian stenting using a combined transradial and transfemoral access with compliant balloon catheters at the vertebral ostium for prevention of distal emboli may represent an alternative therapeutic approach for the treatment of SA stenosis and occlusions.

Abstract WMP5: CT Perfusion Profiles of Infarct Growth in Large Vessel Occlusion Acute Stroke Patients Sensitive to Decreases in Blood Pressure

The growth of a final infarct volume largely depends on cerebral perfusion after a large vessel occlusion (LVO) stroke. Decreases of blood pressure (BP) before recanalization are associated with larger infarct and worse functional outcome. It is uncertain whether an intervention to elevate BP improves outcome, particularly if susceptibility to the BP beneficial effect varies by individual factors such as the collateral vessel status. We aim to define the association of BP, infarct growth and perfusion patterns of potential vulnerable patients. We retrospectively studied patients with anterior LVOs who underwent mechanical thrombectomy (MT) at two comprehensive stroke centers. Only patients with TICI score ≥2b and admission CTP and 24 hours MRI were included. Infarct growth was calculated as 620 ADC volume subtracted from CBF <30% in the ischemic hemisphere using the Automatic Rapid Software. Hypoperfusion intensity ratio (HIR) was calculated as the ratio of the Tmax >10s volume to the Tmax >6s volume with a lower value indicating a more favorable ratio. Intra-procedural BP was continuously monitored using a non-invasive cuff or intraarterial catheter. Systolic BP (SBP) and mean arterial pressure (MAP) were averaged at various time points throughout MT. We analyzed 199 patients from 317 MT. A quantile regression with quantile τ = 0.25, 0.5 and 0.75 was fitted to study how Infarct Growth Rate (IGR) is affected by BP change. At 0.25 and 0.5 quantiles, one unit change in MAP did not lead to a significant change for IGR. At the 0.75 quantile (quartile 3), one unit change in MAP resulted in 0.79 unit change in IGR (95% CI: -0.11, 1.69; p= 0.09). Hence, we identified patients whose IGR is above the 0.75 quantile as the vulnerable subgroup. The vulnerable subgroup had significant larger median volumes of Tmax in all sequences when compared to the non-vulnerable subgroup: Tmax10 (67.8cc vs 40.0cc, p= 0.004), Tmax8 (92.9cc vs 62.0cc, p= 0.003), Tmax6 (134cc vs 98.7cc, p =0.003), Tmax4 (228.6cc vs 184.3cc, p= 0.016). The median HIR was also significantly higher (0.4 vs 0.3, p= 0.026) in the BP vulnerable population. Admission perfusion patterns of collaterals evaluated may help to identify the most vulnerable population to increase their infarct growth when facing decrease in BP.