Mechanical thrombectomy of acute distal posterior cerebral artery occlusions

Multicenter evaluation of mechanical thrombectomy for distal medium vessel occlusions with National Institute of Health Stroke Scale Scores ≥ 6 and ≤ 6

BACKGROUND

While mechanical thrombectomy is considered standard of care for large vessel occlusions, scientific evidence to support treatment for distal and medium vessel occlusions remains scarce.

PURPOSE

To evaluate feasibility, safety, and outcomes in patients with low National Institute of Health Stroke Scale scores undergoing mechanical thrombectomy for treatment of distal medium vessel occlusions.

MATERIALS AND METHODS

Retrospective data review and analysis of prospectively maintained databases at 41 academic centers in North America, Asia, and Europe between January 2017 and January 2022. Characteristics and outcomes were compared between groups with low stroke scale score (≤ 6) versus and higher stroke scale scores (> 6). Propensity score matching using the optimal pair matching method and 1:1 ratio was performed.

RESULTS

Data were collected on a total of 1068 patients. After propensity score matching, there were a total of 676 patients included in the final analysis, with 338 patients in each group. High successful reperfusion rates were seen in both groups, 90.2% in ≤ 6 and 88.7% in the > 6 stroke scale groups. The frequency of excellent and good functional outcome was seen more common in low versus higher stroke scale score patients (64.5% and 81.1% versus 39.3% and 58.6%, respectively). The 90-day mortality rate observed in the ≤ 6 stroke scale group was 5.3% versus 13.3% in the > 6 stroke scale group.

CONCLUSION

Mechanical thrombectomy in distal and medium vessel occlusions, specifically in patients with low stroke scale scores is feasible, though it may not necessarily improve outcomes over IVT.

Endovascular therapy for posterior cerebral artery occlusion: systematic review with meta-analysis

Endovascular therapy (EVT) is a highly effective stroke treatment, but trials validating this intervention did not include patients with posterior cerebral artery (PCA) occlusion. The aim of this systematic review with meta-analysis was to assess the efficacy and safety of EVT for acute PCA occlusion. PubMed, Scopus, ISI, and CENTRAL were searched for studies assessing EVT in adult patients with PCA occlusion. Outcomes of interest were recanalization, symptomatic intracerebral haemorrhage (sICH), mortality, functional independence, and excellent functional outcome at 90 days. Frequencies and odds ratios (ORs) were pooled using random effect models and heterogeneity was measured using the I2 statistic and explored by means of meta-regression. Fifteen studies were included, all observational. Recanalization rates were high [81%, 95% CI (73-88%)] and sICH rates low [2%, 95% CI (1-4%)]. Heterogeneity was high for recanalization (I2 = 80%) but not for sICH, and not accounted for by any of the moderators tested. Compared to best medical treatment, EVT was associated with higher chances of sICH [OR = 2.04, 95% CI (1.12-3.71)] and no effect in functional independence [OR = 0.98, 95% CI (0.63-1.54)], with a tendency to higher chances of excellent functional outcome [OR = 1.29, 95% CI (0.90-1.86)] and mortality [OR = 1.56, 95% CI (0.84-2.90)]. EVT for acute PCA occlusion is technically feasible but associated with higher chance of sICH. There is no evidence to support this treatment to achieve higher rates of functional independence, but other gains that can impact patients' quality of life cannot be excluded. More studies are required with robust design, better patient selection, and comprehensive outcome evaluation.

Mechanical thrombectomy for the treatment of primary and secondary distal medium-vessel occlusion stroke: systematic review and meta-analysis

BACKGROUND

There is limited evidence on the indication and role of mechanical thrombectomy (MT) in patients with distal medium-vessel occlusions (DMVOs). The aim of this systematic review and meta-analysis was to evaluate all the evidence available on the efficacy and safety of MT techniques (stent retriever, aspiration) in primary and secondary DMVOs.

METHODS

Five databases were searched from inception to January 2023 for studies of MT in primary and secondary DMVOs. Outcomes of interest included favorable functional outcome (90-day modified Rankin scale (mRS) 0-2), successful reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2b-3), symptomatic intracerebral hemorrhage (sICH), and 90-day mortality. Prespecified subgroup meta-analyses according to the specific MT technique and to the vascular territory (distal M2-M5, A2-A5, P2-P5) were also performed.

RESULTS

A total of 29 studies with 1262 patients were included. For primary DMVOs (n=971 patients), pooled rates of successful reperfusion, favorable outcome, 90-day mortality and sICH were 84% (95% confidence interval (CI) 76 to 90%), 64% (95% CI 54 to 72%), 12% (95% CI 8 to 18%), and 6% (95% CI 4 to 10%), respectively. For secondary DMVOs (n=291 patients), pooled rates of successful reperfusion, favorable outcome, 90-day mortality and sICH were 82% (95% CI 73 to 88%), 54% (95% CI 39 to 69%), 11% (95% CI 5 to 20%), and 3% (95% CI 1 to 9%), respectively. Subgroup analyses by MT technique and by vascular territory showed no differences in primary and secondary DMVOs.

CONCLUSION

Our findings suggest that MT using aspiration or stent retriever techniques appears to be effective and safe in primary and secondary DMVOs. However, given the level of evidence of our results, further confirmation in well-designed randomized controlled trials is needed.

Feasibility and safety of ADAPT in acute distal posterior cerebral artery occlusions

PURPOSE

The direct aspiration first pass technique (ADAPT) is an effective and safe endovascular treatment for distal medium vessel occlusions (DMVO) of the anterior circulation. Clinical experience with ADAPT in the distal posterior circulation, however, is still limited and published data is scarce. In this original work, feasibility, safety and efficacy of ADAPT with distal access catheters (DAC) for treatment of acute distal posterior cerebral artery occlusions (DPCAOs) is evaluated.

METHOD

All acute ischemic stroke patients between 2017 and 2022 with primary or secondary DPCAOs in the P2 or P3 segment, that underwent thrombectomy of the DPACO using ADAPT with DACs as frontline therapy, were identified. Demographic data, recanalization rates, procedural safety, and clinical outcome were assessed.

RESULTS

Twenty-four patients with primary (n = 6) or secondary (n = 18) DPCAOs (P2: 21/24; P3: 3/24) were included. Median NIHSS score at admission was 14.5 (IQR 9.5). In all cases, the DPCAO could be reached with the DAC. Successful revascularization (DMVO-p-TICI ≥ 2b) with ADAPT was achieved in 79.2% (19/24), including a first pass effect of 62.5% (15/24), leading to complete recanalization (DMVO-p-TICI 3). Median number of passes was 1 (range 1-2). No complications related to distal PCA aspiration thrombectomy occurred. Median NIHSS and mRS scores at discharge were 4 (IQR 8) and 3 (IQR 2), respectively.

CONCLUSIONS

ADAPT appears to be feasible, safe and effective for the treatment of acute DPCAOs in the setting of different occlusion patterns. High revascularization rates without procedural complications can be achieved. Further studies are needed to consolidate these results.

Endovascular Therapy versus No Endovascular Therapy in Patients receiving Best Medical Management for Acute Isolated Occlusion of the Posterior Cerebral Artery: Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Endovascular therapy (EVT) is increasingly reported for treatment of isolated posterior cerebral artery (PCA) occlusions although its clinical benefit remains uncertain. This study-level meta-analysis investigated functional outcome and safety of EVT and best medical management (BMM) compared to BMM for treatment of PCA occlusion stroke.

METHODS

We conducted a literature search in PubMed, Web of Science and Embase for articles reporting patients with isolated PCA occlusion stroke treated with EVT+BMM or BMM including intravenous thrombolysis. There were no randomized trials and all studies were retrospective. Primary outcome was a modified Rankin Scale score of 0-2 at 3 months; safety outcomes included mortality rate and incidence of symptomatic intracranial hemorrhage.

RESULTS

Twelve articles with a total of 679 patients were included in the meta-analysis consisting of 338 patients with EVT+BMM and 341 patients receiving BMM alone. Good functional outcome at 3 months was achieved in 58.0% [95% confidence interval (CI) 43.83-70.95] of patients with EVT+BMM and 48.1% [95% CI 40.35-55.92] of patients with BMM with respective mortality rates of 12.6% [7.30-20.93] and 12.3% [8.64-17.33]. Symptomatic intracranial hemorrhage occurred in 4.2% [95% CI 2.47-7.03] of patients with EVT+BMM and 3.2% [95% CI 1.75-5.92] of patients with BMM. Comparative analyses were performed of publications reporting both treatments and demonstrated no significant differences.

CONCLUSIONS

The results demonstrate that EVT represents a safe treatment for patients with isolated PCA occlusion stroke. There were no differences in clinical or safety outcomes between treatments, supporting randomization of future patients into distal vessel occlusion trials.

Acute Treatment of Isolated Posterior Cerebral Artery Occlusion: Single Center Experience

BACKGROUND AND OBJECTIVES

Randomized trials for mechanical thrombectomy (MT) excluded patients with ischemic strokes due to isolated posterior cerebral artery occlusion (IPCAO), and there is no evidence for best acute treatment strategy in these patients. We aimed to assess the effectiveness and safety of MT in acute IPCAO.

METHODS

We retrospectively analyzed consecutive patients with acute stroke due to IPCAO submitted to MT and/or intravenous thrombolysis (IVT), between 2015-2019. Effectiveness outcomes (recanalization rate, first-pass effect, NIHSS 24h improvement and 3-month Modified Ranking Scale - mRS) and safety outcomes (complications, symptomatic intracranial hemorrhage (SICH) and 3-month mortality) were described and compared between groups.

RESULTS

A total of 38 patients were included, 25 underwent MT and 13 had IVT alone. Successful and complete recanalization were achieved in 68% and 52% of MT patients, respectively. NIHSS improvement at 24h was found in 56% of MT patients versus 30.8% of patients submitted to IVT alone (OR [95% CI]=2.86 [0.69-11.82]) and excellent functional outcome at 3 months (mRS≤1) was achieved in 54.2% of MT patients versus 38.5% in the IVT group (OR [95% CI]=1.60 [0.41-6.32]). Complications occurred in 3 (12%) procedures and there were no SICH. Mortality at 3 months was 20% in the MT group and 15.4% in patients submitted to IVT alone.

CONCLUSIONS

Our results reflect a real-world scenario in a single center and seem to support the recently growing literature showing that MT is a feasible and safe treatment in IPCAO, with favorable effectiveness.