The effect of distal aspiration catheter position on collateral flow in mechanical thrombectomy - an in vitro study

Prolonged intracranial catheter dwell time exacerbates penumbral stress and worsens stroke thrombectomy outcomes

BACKGROUND

The duration of mechanical thrombectomy (MT) is a negative predictor of outcomes in acute ischemic stroke (AIS), yet the precise mechanisms are unclear. We investigated whether the placement of large-bore catheters intracranially reduces blood flow to the ischemic penumbra and diminishes the efficacy of MT.

METHODS

We investigated the impact of different catheter sizes on flow through the intracranial circulation using an in vitro model. Data from a multicenter international registry of AIS patients undergoing MT between January 2016 and December 2023 were reviewed. Intracranial procedure time (icPT) from catheter placement to thrombectomy completion was analyzed using propensity score (PS) matched analysis of patients with successful recanalization achieved in <30 min versus ≥30 min (n=1006/group). Primary outcome was modified Rankin Scale (mRS) score at 90 days (mRS 0-2 favorable). Secondary outcomes included mortality, symptomatic intracranial hemorrhage (sICH), and need for craniectomy.

RESULTS

Using our flow model, we demonstrated a significant reduction in middle cerebral artery and anterior cerebral artery blood flow with the use of larger caliber catheters in the internal carotid artery. Controlling for covariates in 3318 patients, longer icPT predicted lower odds of 90-day favorable outcome (adjusted odds ratio (aOR) 0.87, P<0.01), increased mortality (aOR 1.03, P<0.01), higher decompressive craniectomy rates (aOR 1.07, P<0.01), and increased sICH (aOR 1.07, P<0.01). Each additional 10 mins of icPT correlated with a 13% decrease in recanalization success. The impact of icPT on outcomes was consistent regardless of recanalization success, though catheter size influenced effects. Reduced intraprocedural blood pressure worsened icPT's effects.

CONCLUSIONS

This study is the first to demonstrate the risks associated with the duration of catheter use during MT and to propose strategies to mitigate these risks in AIS.

Comparison of balloon guide catheter versus non-balloon guide catheter for mechanical thrombectomy in patients with distal medium vessel occlusion

BACKGROUND

Several studies have established the safety and efficacy of balloon guide catheters (BGCs) for large vessel occlusions. However, the utility of BGCs remains largely unexplored for distal medium vessel occlusions (DMVOs). In this study, we aim to compare the outcomes of BGC vs. Non-BGC in patients undergoing mechanical thrombectomy (MT) for DMVO.

METHOD

This retrospective study from the Stroke Thrombectomy and Aneurysm Registry (STAR) encompassed adult patients with acute anterior cerebral artery, posterior cerebral artery, and middle cerebral artery-M2-3-4 occlusions. Procedure times, safety, recanalization, and neurological outcomes were compared between the two groups, with subgroup analysis based on first-line thrombectomy techniques.

RESULTS

A total of 1508 patients were included, with 231 patients (15.3%) in the BGC group and 1277 patients (84.7%) in the non-BGC group. The BGC group had a lower modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2C (43.2% vs 52.7%, P=0.01), longer time from puncture to intracranial access (15 vs 8 min, P<0.01), and from puncture to final recanalization (97 vs 34 min, P<0.01). In the Solumbra subgroup, the first pass effect (FPE) rate was lower in the BGC group (17.4% vs 30.7%, P=0.03). Regarding clinical outcomes, the BGC group had a lower rate of distal embolization (8.8% vs 14.9%, P=0.03).

CONCLUSION

Our study found that use of BGC in patients with DMVO was associated with lower mTICI scores, decreased FPE rates, reduced distal embolization, and longer procedure times.

Flow reversal during stroke thrombectomy

When performing mechanical thrombectomy for stroke patients, some physicians use balloon guide catheters (BGCs) in order to achieve flow reversal and thereby improve reperfusion quality. There is substantial evidence favoring the use of BGCs to improve reperfusion rates and clinical outcomes for thrombectomy patients; however, as we will outline in this review, there is also evidence that BGCs do not achieve reliable flow reversal in many circumstances. Therefore, if we are able to modify our techniques to improve the likelihood of flow reversal during thrombectomy maneuvers, we may be able to further improve reperfusion quality and clinical outcomes. This paper provides an overview of concepts on this topic and outlines some potential techniques to facilitate flow reversal more consistently, including a method to visually confirm it, with the aim of making iterative improvements towards optimal reperfusion for stroke patients.