Medtronic touts pooled analysis supporting its stroke-fighting Solitaire stent retriever

Solitaire stent retriever--Screenshot courtesy of Medtronic

A pooled meta-analysis of four clinical trials of the effectiveness of stent retrievers to treat stroke presented at the International Stroke Conference in Los Angeles found that Medtronic's ($MDT) Solitaire device improves functional outcomes and reduced mortality among patients older than 80 from 40% to 20%.

Overall, the Solitaire had a 77% rate of successful revascularization.

The result should not be a surprise, for the four studies published in the New England Journal of Medicine were so positive that they were cut short for ethical reasons, meaning the investigators could no longer justify randomizing patients into the control group. A fifth study was excluded from the analysis because Stryker's ($SYK) competing Trevo ProVue was used in the majority of its cases.

The studies are bringing about a revolution in stroke care. Hospitals are scrambling to add specialized stroke centers, which deploy the devices to treat stroke patients, who are often brought in from community hospitals that do not offer the procedure, known as stent thrombectomy.

The study authors said a pooled analysis was needed to quantify the beneficial effects of stent retrievers and improve subgroup analysis. "There was no heterogeneity in effect in subgroup analysis by age, sex, baseline stroke severity, pretreatment thrombolysis, site of intracranial vascular occlusion, time from onset to randomization or extent of initial noncontrast computed tomography abnormalities, with the exception of the Solitaire as first device population where there was heterogeneity in treatment effect by baseline ASPECTS score," the authors wrote.

But the subgroup of those older than 80 demonstrated a 20 percentage point reduction in mortality. "There is, therefore, no justification for exclusion from thrombectomy purely on the basis of age in clinical practice," the study says.

In June, the American Heart/Stroke Association published guidelines recommending the use of stent retriever technology in conjunction with IV-tPA medication as a first-line treatment for ischemic stroke patients deemed eligible following a CT scan.

Some interventional cardiologists believe they should be permitted to deploy the devices due to the sudden surge of interest in thrombectomy and the resulting potential for a shortage of neurointerventionalists. But 15 neurointerventional medical societies recently released guidelines calling for the devices to be deployed by physicians with a neuroscience background and dedicated training in a specialized stroke center.

- read the study in Stroke (PDF)
- here's the release

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