A retrospective analysis including data from close to 3,000 stroke patients has concluded that early changes in mechanical thrombectomy strategies may be associated with higher reperfusion rates and therefore “should be contemplated” following failed attempts with first-line standalone contact-aspiration or stent-retriever approaches.
The analysis in question—now published in the Journal of NeuroInterventional Surgery (JNIS) by Diogo Haussen, Pedro Martins (both Emory University School of Medicine, Atlanta, USA) and colleagues—was predicated on the fact that, in the authors’ view, although switching to a different thrombectomy technique after initially unsuccessful passes is a common occurrence, its effect remains undetermined.
Haussen, Martins and his colleagues set out to evaluate the association between early changes in thrombectomy approach and reperfusion, doing so via a multicentre, retrospective analysis of prospectively collected data. Their analysis specifically included patients who underwent a thrombectomy procedure for occlusions in the intracranial internal carotid, middle cerebral (M1/M2) or basilar artery. In total, 2,968 patients (median age, 66 years; 52% men) were included.
Changes in thrombectomy technique after either one or two failed passes with a stent retriever alone, contact aspiration alone, or a combined technique incorporating the two, were compared with repeating the previous strategy. The primary outcome of Haussen, Martins and colleagues’ analysis was complete or near-complete reperfusion, defined as an expanded thrombolysis in cerebral infarction (eTICI) score of 2c–3, following each of the second and third thrombectomy passes.
The authors found that changing from a standalone stent-retriever technique to isolated contact aspiration on the second or third pass did not ultimately influence eTICI 2c–3 rates, although changing from a stent retriever to the combined technique after two failed passes led to an increased chance of eTICI 2c–3 (odds ratio [OR], 5.3; 95% confidence interval [CI], 1.9–14.6).
Switching techniques was seen to have had an even more notable impact when changing from a contact aspiration-only approach to a combined technique, owing to a higher likelihood of immediate eTICI 2c–3 after one failed attempt (OR, 2.9; 95% CI, 1.6–5.5) and also after two failed attempts (OR, 2.7; 95% CI, 1.0–7.4). However, switching from contact aspiration to a stent retriever alone was not associated with a significant change in reperfusion outcomes.
Another of Haussen, Martins and colleagues’ primary outcome findings was that, following one or two failed combined-technique attempts, switching to a stent retriever-only approach was not associated with different reperfusion rates. Changing to a contact aspiration-only approach after two failed combined-technique attempts was, however, associated with a reduced chance of eTICI 2c–3 (OR, 0.3; 95% CI, 0.1–0.9).
A final observation that the authors relay in their JNIS report is that rates of functional independence were not significantly different across the analyses—irrespective of the initial thrombectomy approach and any subsequent technique switch.
“Although we acknowledge that clinical outcomes are the most relevant outcome variable, our study was not designed or powered for such analysis,” said Martins, addressing this last detail in conversation with NeuroNews. “Since most patients achieved excellent reperfusion in up to three passes despite changing or repeating strategies, changing by itself is unlikely to account for a huge difference in clinical outcomes. Additionally, time to reperfusion may vary amongst techniques and play a role in the final clinical outcomes. Despite that, we believe that reperfusion remains a valuable intermediate outcome, and our study cannot rule out a potential effect on functional independence.”
“We did not design the study to compare the optimal moment for switching [technique]—the key finding is that changing before three failed passes, which was the paradigm employed in the landmark trials comparing thrombectomy strategies, may be beneficial,” Haussen added, responding to NeuroNews’ question on precisely when it might be best to consider an alternative approach during a thrombectomy case. “Considering that earlier reperfusion has been previously shown to be associated with better clinical outcomes and improved safety, it is reasonable to consider early changes in thrombectomy strategy. Whether and how angioarchitectural, clot composition or clinical characteristics lead to greater responsivity to specific techniques still needs to be established.”
