Study raises questions about possible solutions

Acute ischemic stroke patients who were transferred off-site for endovascular stroke therapy (EST) had higher in-hospital mortality and worse functional outcomes compared with those treated at the presenting location (on-site), a large retrospective study showed.

EST assumed a strikingly more prominent role in stroke following the 2015 publication of research documenting benefits of clot retrieval in acute ischemic stroke caused by LVO. These benefits are time-dependent, though, and despite as many as 85% of the U.S. population living an hour or less from capable EST centers, complications with presentation, decision-making, and the details of physically transferring patients from a presenting site have raised systems and process questions about how to maximize access to EST.

To compare a local EST approach with transferring patients for offsite EST, Mohamad Alkhouli, MD, of the Mayo Clinic in Rochester, Minnesota, and coauthors studied 22,193 adults with acute ischemic stroke who received EST (onsite 50.8%; offsite 49.2%) from October 2015 to September 2019 in the Vizient academic consortium administrative database.

They found that mortality was 14.7% in the off-site group versus 11.2% in the on-site group and poor functional outcomes were 40.7% versus 35.9%, respectively (P<0.001), in propensity score analysis, Alkhouli and colleagues reported in JACC: Cardiovascular Interventions.

Compared with the on-site group, in-hospital mortality OR for the off-site group was 1.38 (95% CI 1.26-1.51; P<0.001) when adjusted for age, sex, demographics, risk factors, tissue plasminogen activator (tPA) use, and institutional EST volume.

Poor functional outcome — which the study authors defined as discharge to hospice, discharge to a long-term nursing facility, or death — was also associated with off-site treatment in similar analyses (OR 1.26, 95% CI 1.18-1.34; P<0.001). Intracranial hemorrhage and mechanical ventilation were higher in the off-site group, while cost was higher in the on-site group.

These findings support “the notion that expanding EST to more sites might improve the outcomes of acute ischemic stroke cases nationwide,” Alkhouli and colleagues wrote.

They also showed there was neither an increase in the number of EST-capable sites nor in the proportion of patients treated onsite versus offsite over time, raising “some important questions: if the clinical benefit of expanding local access to EST is confirmed in further studies, is such an expansion feasible with the current infrastructure?”

While it may seem ideal to staff EST programs entirely with neurointerventionalists, it won’t always be practical, observed Don Heck, MD, of Triad Radiology Associates, Novant Health Forsyth Medical Center, in Winston-Salem, North Carolina, in an accompanying editorial.

“Hospitals exist where having an EST program for ischemic stroke makes sense, and yet becoming a comprehensive stroke center and providing treatment for the full spectrum of neurovascular disease (brain aneurysms, arteriovenous malformations, etc.) with a full complement of neurointerventionalists does not,” he wrote.

“To be clear, when a comprehensive stroke center is nearby, that is where the large vessel occlusion (LVO) patient should initially go,” he continued. “While tPA can work for LVO and should still be given to eligible patients, when one has to choose between tPA and any significant time delay to thrombectomy, the priority should be thrombectomy.”

As for how to address this issue, increases in EST training, mobile units, and using non-neurology or non-neurosurgery specialties with extensive catheter procedure experience have been proposed. A 2019 study of EST performed by cardiologists considered 70 consecutive patients — 10% transferred from off-site — and reported a mean door-to-vascular access time of 64 minutes with a recanalization (Thrombolysis in Cerebral Infarction flow grade 2b or 3) in 93% of patients, with 30-day mortality of 18%. Favorable 3-month clinical outcome (modified Rankin Scale score of 0 to 2) was seen in 61%.

In this study, mean age was 67.9 for onsite patients and 68.4 for offsite, and about half of patients in both groups were female. The onsite group had higher representation of Black participants (23.6% vs 14.4%, P<0.001), more renal disease (prevalence 16.0% versus 13.8%, P<0.001), more prior stroke or transient ischemic attack (13.4% vs 12.0%, P=0.002), and patients who were less likely to receive tPA (8.5% vs 38.9%, P<0.001).

“One glaring difference between the groups is that the off-site group was far more likely to receive tPA (38.9% vs 8.5%, P<0.001),” wrote Heck. “We are told this difference was among those accounted for in the propensity score matching analysis. As all of the transferred patients still had LVO and received EST on arrival, by definition tPA did not ’work’ in this subset of patients.”

Neuroscience-based specialties have published training guidelines for endovascular stroke intervention, which require residency training in neurology, neurosurgery, or radiology, plus at least 1 year fellowship training in neurointervention (effectively excluding interventional radiologists and interventional cardiologists), and indicate optimal hospital requirements: adequate neuroangiography suites, expertise in neurocritical care, vascular neurology, and neurosurgery, and 24/7 access to CT and MRI, Heck noted.

Highly effective EST programs can be and have been developed using interventional radiologists or cardiologists, either alone or to support other neurointerventionalists, he pointed out.

“This requires a commitment of the physicians to the training, not just a weekend course,” he wrote. “Even as technological advances have on average made EST faster and easier, the brain is a very unforgiving place to work even for the experienced.”

Limitations of the analysis include lack of database information about stroke severity, timing of intervention, transfer times and modes, angiographic findings, EST techniques, and outcomes beyond death and discharge destination.

  1. Acute ischemic stroke patients who were transferred off-site for endovascular stroke therapy (EST) had higher in-hospital mortality and worse functional outcomes compared with those treated at the presenting location (on-site), a large retrospective study showed.

  2. The findings raise important questions, including whether expanding local access to EST, if needed, is feasible with the current infrastructure.

Paul Smyth, MD, Contributing Writer, BreakingMED™

Alkhouli reported no disclosures.

Heck reported being a consultant for Stryker.

Cat ID: 38

Topic ID: 82,38,730,8,38,192,925