Better Outcomes Seen for Stroke Patients Taken Directly to Thrombectomy Hospitals, but Protocols Lacking
Two studies look at the effects of transfer on outcomes for stroke patients, and experts call for further system-level improvements.
Patients with acute ischemic stroke due to a large vessel occlusion who present directly to an endovascular-capable hospital receive more rapid treatment and have improved clinical outcomes, including better functional independence, than those who require transfer, according to recently published data from the STRATIS registry.
Another new study, meanwhile, suggests that vascular imaging including assessment of collateral vessels can, in certain patients, help determine exactly who might benefit the most from transfer for mechanical thrombectomy.
While it “just makes sense” that transfer patients would receive delayed treatment, Michael Froehler, MD, PhD (Vanderbilt University Medical Center, Nashville, TN), who led the study on transfer and outcomes, told TCTMD he was surprised at how much the study groups differed with regard to events, especially since all patients received mechanical thrombectomy.
In the study, which included 984 patients with acute stroke due to large vessel occlusion participating in the STRATIS registry, those who presented directly to an endovascular-capable center had a median onset-to-revascularization time of 202 minutes compared with 311.5 minutes for patients who were transferred (P < 0.001).
Sixty percent of patients presenting directly to the endovascular-capable hospital gained functional independence compared with 52.2% of transfer patients (OR 1.38; 95% CI 1.06-1.79). Moreover, an excellent outcome (defined as a modified Rankin Scale Score 0-1) was achieved in 47.4% and 38.0% of direct and transfer patients, respectively (OR 1.47; 95% CI 1.13-1.92). Mortality, however, did not differ between the study arms, and IV-tPA administration did not affect outcomes.
Treatment of stroke has “made tremendous progress over the last few years” to the point that “beyond the shadow of a doubt, endovascular stroke treatment is very beneficial for patients with large vessel occlusion,” Froehler said. “However, that now means we’ve got a lot more work to do in terms of optimizing the system of care to ensure the timely delivery of that therapy.”
The study was published online September 24, 2017, ahead of print in Circulation.
Transfer Process ‘So Slow’
The American Heart Association recently updated their guideline recommendations to support endovascular treatment for those who have large vessel occlusions and are clinically eligible, but not all hospitals are equipped to provide thrombectomy. Less clear is whether the “time is brain” mantra means patients would do best if treated at the closest hospital or if direct transferred to a thrombectomy-capable facility.
To TCTMD, Froehler told the story of a recent 52-year-old patient who presented to a regional hospital within 3 hours of symptom onset with aphasia and right hemiparesis. Together with the physicians at the presenting hospital, Froehler decided to transfer the patient to Vanderbilt for potential thrombectomy.
“Unfortunately, the transfer process was so slow—not for any one single reason, but because it's a process that involves many little steps,” he explained. “He didn’t get here until about 6 hours after that decision to transfer, and by the time he arrived here the infarct was completed and there was nothing I could do.”
This kind of situation “happens all the time,” Froehler said.
The onus for optimizing transfer and ensuring the timely delivery of care falls to the entire medical community, from emergency medicine to neurovascular specialists and hospitals to communities, he added. Emergency medical services (EMS) also has a large role to play in better understanding “the implications of going to hospital A versus hospital B and making an effort to recognize severe stroke up front and using that information to make those triage and transport decisions,” Froehler commented.
A Call for Further Improvement
In the second study, published online September 25, 2017, ahead of print in JAMA Neurology, Gregoire Boulouis, MD, MSc (Massachusetts General Hospital, Boston), and colleagues looked specifically at how multimodality imaging might inform decisions over whether to transfer stroke patients in the first place.
Among 316 patients with acute ischemic stroke presenting to one of 30 referring hospitals in their regional stroke network and eventually transferred for thrombectomy, a higher NIH Stroke Scale score, lower baseline Alberta Stroke Program Early CT Score (ASPECTS), and no or poor collateral blood vessel status were associated with ASPECTS decay on multivariable analysis. The findings held true when patients were stratified by vessel occlusion level.
“The added value of vascular imaging and collateral blood vessel assessment for decision-making regarding transfers requires further evaluation and adequate tailoring to local resources and needs,” the authors write.
In an accompanying editorial, Bruce Campbell, MBBS, PhD (University of Melbourne, Parkville, Australia), writes that these results “contribute to the weight of evidence that, at a minimum, aortic arch to cerebral vertex CT angiography (CTA) should be performed immediately after the noncontrast CT of the brain at the first hospital that assesses the patient.”
For Froehler, improvements in imaging protocols are a step forward, but must be implemented along with other changes despite variables present for each hospital system.
“There’s probably no right answer for the country or the world, but rather systems of care should be optimized according to local geographies,” he said. In his region for example, EMS should be trained to potentially bypass non-endovascular-capable centers for certain cases even when a longer drive is a possibility, the transfer process in general could be improved, and neurointerventionalists should potentially be made available at some regional centers, Froehler suggested.
In the editorial, Campbell notes that stroke patients requiring transfer for mechanical thrombectomy “pose a substantial logistic challenge,” but says systems of care need to be optimized so patients are taken to the correct hospital as fast as possible.
“Imaging has been central to phenotyping stroke pathophysiology to identify patients likely to respond to reperfusion in trials,” he writes. “We now need to adapt these approaches to clinical practice, in which the goal is maximizing the number of patients who benefit from reperfusion. Perceived barriers at primary stroke centers are surmountable, and the most efficient approach is to get the complete imaging information at the initial presentation: do it right the first time.”
Froehler MT, Saver JL, Zaidat OO, et al. Interhospital transfer prior to thrombectomy is associated with delayed treatment and worse outcome in the STRATIS registry. Circulation. 2017;Epub ahead of print.
Boulouis G, Lauer A, Siddiqui AK, et al. Clinical imaging factors associated with infarct progression in patients with ischemic stroke during transfer for mechanical thrombectomy. JAMA Neurol. 2017;Epub ahead of print.
Campbell BCV. Stroke imaging: doing it right the first time. JAMA Neurol. 2017;Epub ahead of print.
- Froehler reports serving as a scientific consultant regarding trial design and conduct to Medtronic.
- Boulouis reports receiving Fulbright and Monahan Foundation grants.
- Campbell reports receiving research support grants from the national Health and Medical Research Council of Australia, Royal Australasian College of Physicians, Royal Melbourne Hospital Foundation, National Heart Foundation, and National Stroke Foundation of Australia and unrestricted grant funding from Covidien (Medtronic).