Increased likelihood of first-pass reperfusion is also associated with use of radiopaque devices and adjuvant local aspiration.
The use of a longer stent retriever—30 mm or 40 mm in length—is an independent predictor of first-pass reperfusion in patients with intracranial internal carotid or middle cerebral artery M1 or M2 occlusions, according to the results of a study published online June 1, 2018 in the Journal of NeuroInterventional Surgery.
“Techniques and technologies for thrombectomy are constantly evolving,” study authors Raul G. Nogueira, MD, and Diogo C. Haussen, MD, of Emory University/Marcus Stroke & Neuroscience Center-Grady Memorial Hospital (Atlanta, GA), said in a written response to Neurovascular Exchange. “Considering the demonstrated safety, versatility, and technical efficacy, longer stent retrievers should be favored in proximal large-vessel occlusion.”
According to Nogueira and Haussen, their experience with active deployment technique for stent retrievers demonstrated that it served to optimize chances of reperfusion. Unfortunately, they said, the downside was that this practice led to substantial foreshortening of the devices. Therefore, they hypothesized that longer retrievers would have a better performance compared with shorter ones.
The researchers retrospectively analyzed data from a thrombectomy database where 4-mm diameter stents were employed as a first-line strategy in patients with large-vessel occlusion acute ischemic strokes who had intracranial internal carotid or middle cerebral artery M1 or M2 occlusions. Procedures were conducted with the aid of a balloon guide catheter between June 2011 to March 2017.
The researchers identified 1,126 thrombectomies performed during that time and included 420 in their analysis. Of these, 221 were treated with long Trevo retrievers (Stryker Neurovascular) that were 4 x 30 mm, or long Solitaire retrievers (Medtronic Neurovascular) that were 4 x 40 mm. The other 199 patients were treated with a short Trevo that was 4 x 20 mm or a short Solitaire that was 4 x 20 mm. At baseline, patients treated with the short retriever had more hypertension, dyslipidemia, and atrial fibrillation than those treated with longer retrievers.
In six in 10 patients, the longer retriever achieved first-pass mTICI 2b/3 reperfusion compared with only five in 10 patients treated with a shorter retriever (62% vs 50%; P = 0.01).
Factors that independently predicted first-pass reperfusion were longer retriever (OR 2.2; 95% CI 1.3-3.6) and use of radiopaque devices (OR 2.1; 95% CI 1.2-3.4).
Finally, the study also demonstrated that adjuvant local aspiration had an independent effect favoring first pass reperfusion even if a balloon guide catheter was concomitantly used.
Adoption of Longer Retrievers ‘Reasonable’
The researchers note that refining procedural techniques has become an important facet of thrombectomy research. With this study, Nogueira and Haussen hypothesized that a longer device would increase the area of device/thrombus interaction, which is especially important in cases with significant clot burden, they said. This would allow a more uniform distribution of forces during retraction.
“Longer devices could minimize the chances of missing the target site in cases of patient restlessness or of tortuous cerebrovascular anatomy,” Nogueira and Haussen said. “Finally, enhancing device purchase past the clot would increase the chance of dragging the clot out if the primary integration with stent struts failed.”
Although they did not examine the interactions that other variables may have had on the relationship between device length and reperfusion, Nogueira and Haussen postulated that the use of longer retrievers would be particularly helpful in situations of larger clot burden, which is typically associated with lengthy occlusions.
Given the findings of the study, Nogueira and Haussen believe that further research is needed.
“Since longer stent retrievers can be partially unsheathed—mimicking a shorter one, which can be useful when the clot is fully covered by the device and there is no reason to add more friction for the pull—and that there are typically no additional costs, it is reasonable to favor longer retrievers as compared to their shorter counterparts,” they said.
However, in the study discussion, they did note that longer retrievers could have disadvantages, “such as a larger area of interface with the vessel and consequently more friction during retrieval, especially in distal and/or tortuous vessels.” In this study though, the rates of subarachnoid hemorrhage were similar between the two groups.
Sources:
Haussen DC, Al-Bayati AR, Grossberg JA, et al. Longer stent retrievers enhance thrombectomy performance in acute stroke. J NeuroIntervent Surg. 2018;Epub ahead of print.
Disclosures:
- Haussen report no relevant conflicts of interest.
- Nogueira reports competing interests with Stryker-Neurovascular (Trevo-2 and DAWN/Trial PI), Covidien (SWIFT and SWIFT-PRIME/Steering- Committee, STAR Trial/Core-Lab), and Penumbra (3-D Separator Trial/Executive-Committee).
