"Adaptative endovascular strategy to the CloT MRI in large intracranial vessel occlusion" (VECTOR): Study protocol of a randomized control trial

Clot composition and recanalization outcomes in mechanical thrombectomy

BACKGROUND

Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

METHODS

Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin-eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of first-pass effect (FPE, modified Thrombolysis in Cerebral Infarction 2c/3) and the number of passes.

RESULTS

A total of 1430 patients of mean±SD age 68.4±13.5 years (median (IQR) baseline National Institutes of Health Stroke Scale score 17.2 (10.5-23), IV-tPA use 36%, stent-retrievers (SR) 27%, contact aspiration (CA) 27%, combined SR+CA 43%) were included. The median (IQR) number of passes was 1 (1-2). FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for red blood cell (RBC)-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes than RBC-rich and mixed clots (median 2 and 1.5 vs 1, respectively; P=0.02). CA showed a trend towards a higher number of passes with fibrin-rich clots (2 vs 1; P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

CONCLUSIONS

Despite the lack of correlation between clot histology and FPE, our study adds to the growing evidence supporting the notion that clot composition influences recanalization treatment strategy outcomes.

Early technique switch following failed passes during mechanical thrombectomy for ischemic stroke: should the approach change and when?

BACKGROUND

Fast and complete reperfusion in endovascular therapy (EVT) for ischemic stroke leads to superior clinical outcomes. The effect of changing the technical approach following initially unsuccessful passes remains undetermined.

OBJECTIVE

To evaluate the association between early changes to the EVT approach and reperfusion.

METHODS

Multicenter retrospective analysis of prospectively collected data for patients who underwent EVT for intracranial internal carotid artery, middle cerebral artery (M1/M2), or basilar artery occlusions. Changes in EVT technique after one or two failed passes with stent retriever (SR), contact aspiration (CA), or a combined technique (CT) were compared with repeating the previous strategy. The primary outcome was complete/near-complete reperfusion, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) of 2c-3, following the second and third passes.

RESULTS

Among 2968 included patients, median age was 66 years and 52% were men. Changing from SR to CA on the second or third pass was not observed to influence the rates of eTICI 2c-3, whereas changing from SR to CT after two failed passes was associated with higher chances of eTICI 2c-3 (OR=5.3, 95% CI 1.9 to 14.6). Changing from CA to CT was associated with higher eTICI 2c-3 chances after one (OR=2.9, 95% CI 1.6 to 5.5) or two (OR=2.7, 95% CI 1.0 to 7.4) failed CA passes, while switching to SR was not significantly associated with reperfusion. Following one or two failed CT passes, switching to SR was not associated with different reperfusion rates, but changing to CA after two failed CT passes was associated with lower chances of eTICI 2c-3 (OR=0.3, 95% CI 0.1 to 0.9). Rates of functional independence were similar.

CONCLUSIONS

Early changes in EVT strategies were associated with higher reperfusion and should be contemplated following failed attempts with stand-alone CA or SR.

A Meta-analysis of Combined Aspiration Catheter and Stent Retriever versus Stent Retriever Alone for Large-Vessel Occlusion Ischemic Stroke

BACKGROUND

The efficacy of combined aspiration catheter and stent retriever compared with stent retriever alone for the treatment of large-vessel occlusion acute ischemic stroke is unclear.

PURPOSE

Our aim was to conduct a systematic literature review and meta-analysis on several metrics of efficacy comparing aspiration catheter and stent retriever with stent retriever alone.

DATA SOURCES

MEDLINE and the Cochrane Library Databases were searched. Randomized controlled trials and case-control and cohort studies were included.

STUDY SELECTION

Ten comparative studies were included detailing a combined 1495 patients with aspiration catheter and stent retriever and 1864 with stent retrievers alone.

DATA ANALYSIS

Data on first pass effect (TICI 2b/2c/3 after first pass), final successful reperfusion (modified TICI ≥2b), and 90-day functional independence (mRS ≤ 2) were collected. Meta-analysis was performed using a random-effects model.

DATA SYNTHESIS

There was a pooled composite first pass effect of 40.8% (611/1495) versus 32.6% (608/1864) for aspiration catheter and stent retriever and stent retriever alone, respectively (P < .0001). Similarly, on a meta-analysis, aspiration catheter and stent retriever were associated with a higher first pass effect compared with stent retriever alone (OR = 1.63; 95% CI, 1.20-2.21; P = .002; I² = 72%). There was no significant difference in composite rates of successful reperfusion between aspiration catheter and stent retriever (72.8%, 867/1190) and stent retriever alone (70.8%, 931/1314) (P = .27) or on meta-analysis (OR = 1.31; CI, 0.81-2.12; P = .27; I² = 82%). No difference was found between aspiration catheter and stent retriever and stent retriever alone on 90-day functional independence (OR = 1.02; 95% CI, 0.77-1.36; P = .88; I² = 40%).

LIMITATIONS

This study is limited by high interstudy heterogeneity.

CONCLUSIONS

On meta-analysis, aspiration catheter and stent retriever are associated with a superior first pass effect compared with stent retriever alone, but they are not associated with statistically different final reperfusion or functional independence.

Direct aspiration stroke thrombectomy: a comprehensive review

Mechanical thrombectomy is now the standard of care for acute ischemic stroke patients with large vessel occlusions, and can be performed with several devices and techniques. One of these techniques, direct aspiration (DA), consists of navigating a large-bore catheter up to the face of the clot and initiating forceful suction. This comprehensive review has three objectives: (1) to describe the direct aspiration technique; (2) to present the available evidence regarding predictive factors of DA success and performance compared with other techniques; and (3) to discuss the forthcoming improvements in distal aspiration.