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Response to Posterior Circulation Stroke Delayed in Canada
OTTAWA — The identification and treatment of posterior circulation stroke (PCS) are delayed, compared with anterior circulation stroke (ACS), Canadian data suggested. Researchers described a recent analysis at the Canadian Neurological Sciences Federation (CNSF) Congress 2025.
'The symptoms of a PCS are not the typical symptoms that we tell patients to recognize as a stroke,' study investigator Julián Alejandro Rivillas, MD, a fellow in vascular neurology at the Université de Montréal and Centre Hospitalier de l'Université de Montréal, told Medscape Medical News .
Prehospital scales like the Cincinnati Prehospital Stroke Scale, which is often used by emergency medical services, assess for facial droop, arm drift, and abnormal speech. But these scales would not detect a PCS, noted Rivillas.
The signs of a PCS generally are not familiar to the public and to first-line responders. This unfamiliarity leads to failure to recognize a PCS promptly, transport a patient quickly to the hospital, and initiate treatment promptly. Thus, the opportunity for intravenous thrombolysis (IVT) is sometimes lost, explained Rivillas. The symptoms of a PCS can include dizziness, hearing loss, difficulty swallowing, double vision, and loss of balance.
Registry Data Analyzed
The investigators analyzed data from 2018 to 2022 from 20 Canadian stroke centers that participated in the OPTIMISE registry. They included 6391 patients (5929 with ACS and 462 with PCS) in their analysis. Patients with PCS were younger (67 years vs 71.3 years; P < .001), more often men (61.9% vs 48.6%; P < .001), had longer onset-to-door times (362 minutes vs 256 minutes; P < .001), longer door-to-needle times (172 minutes vs 144 minutes; P = .0016), and longer onset-to-puncture times (459 minutes vs 329 minutes; P < .001).
The researchers also observed that patients with PCS had a lower rate of IVT (39.8% vs 50.4%; P < .001) and more frequently underwent general anesthesia (47.6% vs 10.6%; P < .001).
'This is a time-dependent treatment. Generally, we have four and a half hours to give these medications in a safe way,' said Rivillas. Administering medications outside that window entails a risk for intracranial hemorrhage. 'We have a small window of time where we can administer thrombolytics in a safe way.'
If clinicians are not able to treat a stroke with IVT within the recommended period, then mechanical thrombectomy will likely be performed. This finding explains why general anesthesia is used more often in PCS management than in ACS management, said Rivillas. 'The PCS tends to require general anesthesia because the procedure is more complex.'
Functional Outcomes Assessed
This analysis found that the difference in the rate of modified Rankin Scale (mRS) of 0 at 90 days between patients with ACS and those with PCS (25.8% vs 20.1%) was not significant. Similarly, the difference in the rate of mRS of 1 at 90 days between patients with ACS and those with PCS (27.8% vs 25.3%) was not significant.
Despite the similarities in the 3-month functional outcomes between the two groups of patients, Rivillas stressed that the data only captured part of the picture, since this follow-up 90-day analysis failed to capture the entire patient population.
'We don't know what happened with the other 50% of the patients,' said Rivillas. The investigators could not conclude that functional outcomes were the same at 90 days across arms because a lot of data were missing.
Broad Education Needed
'Clinically, ischemic stroke due to a posterior circulation occlusion is more difficult to recognize and evaluate,' Michael D. Hill, MD, professor of medicine at the University of Calgary's Cumming School of Medicine, Calgary, told Medscape Medical News . 'Thus, delays in presentation (prehospital level) and delays in care (hospital level) are known to occur, and these data confirm and quantify those differences,' said Hill, who also is president of CNSF and did not participate in the study.
A training initiative is therefore necessary, he said. 'The solution, then, is education for all manner of healthcare personnel (from the public to prehospital to in-hospital at all levels of training and expertise) so that stroke can be recognized.'
