Direct Angiography Gains Credence for Hospitals Receiving Stroke Transfers

Large vessel occlusion (LVO) stroke patients undergoing interhospital transfer enjoyed faster treatment and better clinical outcomes if they skipped the CT and instead went straight to the angiography suite upon arrival at the thrombectomy-capable center, according to an observational study.

The direct to angiography (DTA) strategy was associated with improvement in 90-day functional independence compared with usual repeated imaging (52.6% vs 37.0%; adjusted OR 1.85, 95% CI 1.33-2.57) with a trend toward reduced 90-day mortality as well (17.0% vs 24.4%, adjusted OR 0.66, 95% CI 0.37-1.20), Amrou Sarraj, MD, of the University of Texas McGovern Medical School in Houston, and colleagues found.

Faster treatment times may have contributed to the improvement in functional independence. With the DTA strategy, LVO stroke patients spent less time from arrival at the comprehensive stroke center to groin puncture (median 34 vs 60 minutes, P<0.001), the investigators reported in JAMA Neurology.

The study included more than 1,100 patients with LVO stroke who received endovascular therapy (EVT) at one of six hospitals. Results were the same whether patients received early (0 to 6 hours) or late (>6 to 24 hours) treatment, and whether they presented during regular work hours or on-call hours at the hospital. The primary outcome measure was functional independence at 3 months (modified Rankin Scale score of 0-2).

Ultimately, the study is consistent with the recent ANGIOCAT randomized trial that also favored DTA transfer at one Spanish center — albeit with some differences.

“Our study incorporated a pragmatic, real-world approach with patients presenting in both regular and on-call hours, whereas ANGIOCAT represented the patients enrolled in optimal scenario, when the angiography team is available. That said, the effect size of DTA vs repeated imaging approach in our study is very similar to what was shown in ANGIOCAT,” Sarraj’s group said.

Guidelines currently require evidence of salvageable tissue when treating LVO strokes beyond the 6-hour window. The aim of repeated imaging after interhospital transfer is to catch progressing infarcts to ensure an ongoing target for EVT.

Now, however, the present report “adds weight to the concept that imaging should not be universally repeated on arrival at an EVT capable stroke center,” according to Bruce Campbell, MBBS, PhD, of Royal Melbourne Hospital in Australia, who added that there are increasingly sophisticated flat-panel perfusion imaging solutions for the angiography suite.

“The reasons to obtain a repeated CT scan after transfer for EVT are therefore diminishing. Clinicians should critically challenge what difference repeated imaging would make to management of the individual patient they are treating and balance that against the detrimental effect on functional outcome incurred by delaying reperfusion to repeat imaging,” Campbell wrote in an accompanying editorial.

Notably, it was the subgroup of DTA patients transferred quickly to the EVT center that drove the observed improvement in functional outcomes: inter-facility transfer times greater than 3 hours correlated with a decrease in rates of modified Rankin Scale scores of 0-2 (59.6% vs 35.7%, P=0.006) in the DTA group.

Longer transfer times did not affect this outcome for the repeated imaging group (36.1% vs 37.0%, P=0.85). Nevertheless, each 10-minute increase in time from EVT-center arrival to groin puncture was linked with a 5% reduction in functional independence (adjusted OR 0.95, 95% CI 0.91-0.99) for these patients.

Thus, “repeated imaging may be reasonable in patients with prolonged transfer times,” Sarraj and co-authors concluded. “Optimizing EVT workflow in transferred patients may result in faster, safe reperfusion with higher chances of achieving functional independence.”

The multicenter, retrospective cohort study included 2,533 stroke patients transferred from a non-EVT center to a comprehensive stroke center, of whom 1,140 were determined to have an LVO and received EVT within 24 hours from last-known-well time. This cohort was split between the 28.7% who went DTA and 71.3% undergoing repeated imaging.

Median age was 69 years, and 46.4% of patients were women. The two groups were generally similar at baseline except that patients undergoing DTA had greater use of IV alteplase (61.2% vs 51.0%, P=0.002).

The observational nature of the study left room for selection bias. However, stroke severity and time from onset to arrival at the EVT center were similar between the groups, Campbell noted.

“Notably, there was no difference in symptomatic hemorrhagic transformation rates in Sarraj et al or the ANGIOCAT study, suggesting that exclusion of patients at risk of a poor outcome had a limited effect on patient safety,” Campbell suggested.

Given the well-known effect of EVT timing on patient outcomes, other efforts to expedite stroke treatment include prehospital triaging directly to EVT-capable centers, Sarraj and co-authors noted.