Functional outcomes after thrombectomy for ischemic stroke in the late window are similar for transferred patients and patients directly admitted to the treating hospital, according to a subanalysis from the DEFUSE 3 trial.

“Stroke patients presenting to non-thrombectomy centers with a reasonable imaging profile who otherwise are eligible for thrombectomy should be strongly encouraged to be transferred to a thrombectomy-capable center,” Dr. Amrou Sarraj from University of Texas Health Science Center at Houston, Houston, Texas told Reuters Health by email. “At the same time, research is needed to improve direct access to thrombectomy in stroke patients.”

DEFUSE 3 demonstrated the efficacy and safety of endovascular thrombectomy up to 16 hours after last-known-well time in patients selected by perfusion imaging. Whether transferred patients have worse outcomes, as suggested in prior studies, remains unclear.

Dr. Sarraj and colleagues assessed the safety and efficacy of endovascular thrombectomy in 121 patients who were transferred from outside hospitals compared with 61 patients who presented directly to the study site in the DEFUSE 3 trial.

In the transfer group, the median time from stroke onset to arrival at the study site was about 30 minutes longer than it was for patients presenting directly, according to a JAMA Neurology online report.

In both groups, endovascular thrombectomy was associated with a more favorable distribution of functional outcome scores at three months than was medical management.

Successful angiographic reperfusion was identical (76 percent) in the direct and transfer groups, and there was no difference between the groups in the likelihood of good outcome with thrombectomy in the three prespecified treatment windows (6–9 hours, 9–12 hours, and 12–16 hours).

Mortality rates at 90 days were non-significantly lower in patients receiving thrombectomy (versus medical management), irrespective of whether they were transferred or presented directly to the study site.

There were no significant differences between transferred and direct patients in regard to any safety outcome.

“The results have health care implications indicating that transferring patients for late-window thrombectomy is associated with substantial clinical benefits and should be strongly encouraged,” the researchers conclude.

Dr. Marc Fisher from Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, who has researched various aspects of endovascular therapy for acute ischemic stroke, told Reuters Health by email, “I did not find the results of this analysis to be surprising at all, because patients were chosen for thrombectomy based upon strict imaging criteria that were similar for the transfer group and those presenting at the thrombectomy center. If the imaging parameters were the same, you would expect the outcomes to be the same, as was observed.”

“The observation that the outcomes were the same for both types of patients should lead to the performance of the same type of advanced imaging, ie, CT perfusion or diffusion/perfusion MRI, for both transfer patients and those presenting at a thrombectomy center,” he said.

“Further studies are needed to determine what the efficacy boundaries are for the benefits of thrombectomy,” Dr. Fisher said. “What I am suggesting is we know that it is highly effective for patients with small ischemic cores and large mismatches between ischemic core and ischemic penumbra, and we now need to identify how large an ischemic core can be before treatment efficacy is lost.”