Prospective studies are needed to determine whether there is a role for balloon guide catheters to produce low-flow conditions in posterior circulation strokes.
In patients with basilar artery strokes, the presence of contralateral low-flow conditions is associated with higher rates of complete recanalization, which in turn is tied to better clinical outcomes, according to a study published recently in Stroke.
“Posterior circulation strokes are quite rare (only about 10% of all recanalized patients). Therefore, a lot of questions are underinvestigated in this subgroup of patients,” lead author Tobias Boeckh-Behrens, MD (Technical University Munich, Germany), told Neurovascular Exchange in an email. He added that “showing that these patients really have a good chance of a good neurological outcome if they are . . . completely recanalized is one important aspect of our study.”
The other important goal of the study, he explained, was to demonstrate that antegrade flow blockade is important in posterior circulation strokes, as it is known to be in strokes of the anterior circulation.
Boeckh-Behrens and colleagues conducted a retrospective review of 115 consecutive patients (mean age 71.5 years; 34% women) with basilar artery occlusions that were treated with second-generation thrombectomy devices at a single center. Median NIHSS score at admission was 15. The investigators sought to determine how patient characteristics, occlusion length, collateral circulation, underlying stenosis, incomplete occlusions, and patency of the vertebral arteries were related to recanalization success.
Complete recanalization was more frequently achieved among patients with contralateral low-flow conditions, defined as an aplastic or hypoplastic vertebral artery contralateral to the catheter position (80.6% vs 50.0%). The presence of contralateral low-flow conditions remained an independent predictor of complete recanalization on multivariate analysis (adjusted OR 5.81; 95% CI 1.97-17.19).
Furthermore, compared with patients with incomplete posterior recanalization, those with successful procedures had lower in-hospital mortality (16.4% vs 41.7%) and were more likely to attain an mRS ≤ 3 (49.4% vs 8.3%). The latter remained significant after adjusting for potential confounders (adjusted OR 15.93; 95% CI 1.42-179.00).
A Potentially Great Advance
According to Boeckh-Behrens, the findings “further support the notion not to withhold this very effective therapy for patients with posterior circulation occlusions, despite [lack of] high-level, class A evidence for these cases. . . . Second, it suggests [the need] to think about the possible usage of balloon guide catheters for recanalization therapy in the posterior circulation, and additionally to block the contralateral vertebral artery by a second balloon in cases where both arteries are equally patent.”
Commenting for Neurovascular Exchange, Ulf Jensen-Kondering, MD (University Hospital of Schleswig-Holstein, Kiel, Germany), said “the results suggest a benefit of contralateral flow modulation or ipsilateral balloon guide catheter use. If the proposed mechanism and the desired interventional strategy is able to increase recanalization rates, this would be a great [advance] for this rare but devastating disease.” He noted that the main limitation of the study is its retrospective nature.
Boeckh-Behrens said he and his colleagues are planning a prospective trial to evaluate this approach, and if the results are confirmed, “blocking of the contralateral artery in bilaterally patent vertebral arteries should then be considered as a standard technique in posterior circulation recanalization procedures.”
Boeckh-Behrens T, Pree D, Lummel N, et al. Stroke. 2019;50:389-395.
Boeckh-Behrens and Jensen-Kondering report no relevant conflicts of interest.