Strokes Linked to COVID-19 Are More Severe, More Likely Embolic

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Among COVID-19 patients who suffer stroke, the rate of cryptogenic and embolic strokes is higher than what is usually seen, a new study shows.

The New York study also shows that strokes in COVID-19 patients were more severe, the death rate was higher, and patients were younger than was seen in strokes not associated with COVID-19.

The study, along with four other studies from around the globe, showed a significantly lower number of stroke hospitalizations as well as an increase in delays in treatment during the COVID-19 crisis than during the same period last year.

The five studies were published online in Stroke.

In the New York study, researchers led by Shadi Yaghi, MD, NYU Grossman School of Medicine, compared the clinical characteristics of stroke patients who also had COVID-19 and were treated in the New York metropolitan area to a historical cohort of patients with ischemic stroke who underwent treatment at the same hospital system in 2019 (contemporary control patients).

Results showed that during the study period in 2020, of 3556 patients hospitalized with severe COVID-19, 32 patients (0.9%) had imaging-proven ischemic stroke.

This rate is lower than the rate reported in Chinese COVID-19 studies. The rate for the New York patients may have been underestimated, because the detection of symptoms of ischemic stroke is challenging in patients who are critically ill with COVID-19 and who are intubated and sedated, the authors say.

Cryptogenic stroke was more common in patients with COVID-19 (65.6%) as compared to contemporary control patients (30.4%) and historical control patients (25.0%). Of the COVID-19 stroke patients, 34.4% had an embolic stroke of undetermined source.

When compared with contemporary control patients, COVID-19 patients tended to be younger (average age, 63 years, vs 70 years for non–COVID-19 stroke patients). In the COVID-19 patients, strokes tended to be more severe (average NIHSS score, 19 vs 8), the patients' D-dimer levels were higher (10,000 vs 525 ng/mL), and they were more likely to be treated with antithrombotics (75% vs 24%). The mortality rate among the stroke patients with COVID-19 was far higher (63.6% vs. 9.3%).

The authors note that 69% of the COVID-19 stroke patients required mechanical ventilation, which renders patients vulnerable to many complications that could increase stroke risk. Additionally, severe COVID-19 has been associated with a hyperinflammatory state and hyperviscosity.

The investigators say their results support the suggestion that stroke in COVID-19 patients could be a manifestation of systemic hypercoagulability. They note that ongoing studies are testing the use of therapeutic anticoagulation for stroke and other means of preventing thrombotic events in select patients with COVID-19. Laboratory evidence is suggestive of hypercoagulability.

The study found that fewer patients with stroke were hospitalized in the study period in 2020 than in the same period in 2019.

"This witnessed low volume of acute emergencies during the COVID-19 pandemic has been observed in other institutions as well," the authors point out. "The reasons for this are unclear but possibly that patients with stroke and mild symptoms are staying at home and not presenting to the emergency department for stroke treatment," they add.

COVID-19 Causing Care Delays

Similar findings of fewer cases of stroke are reported in a Chinese study of 227 hospitals, which found a drop of around 25% in the number of thrombolysis and thrombectomy cases in February 2020 as compared with February 2019.

"The most prominent factor was that patients with stroke were not coming to the hospital for various reasons," the authors say.

They note that the screening process for COVID-19 interfered with stroke care ― laboratory resources and CT scanners were utilized by many patients who were being evaluated for possible COVID-19, which caused significant in-hospital delays for stroke patients.

They conclude: "Enhanced stroke awareness activities, proper resource management, and stroke center designation during the crisis are needed."

A study from Barcelona, Spain, found that the COVID-19 pandemic reduced by a quarter the number of stroke admissions and thrombectomies performed at one comprehensive stroke center compared to the the previous year, but quality-of-care metrics were not affected. During the lockdown, there was an overload of emergency calls, but there were fewer stroke code activations, particularly for elderly patients.

"In addition to in-hospital contingency plans, patient transport systems and public education remainders must be intertwined to better protect the patients with acute stroke in these uncertain times," the authors conclude.

Stroke Patients Presenting Later

In a study conducted in Hong Kong, researchers found that stroke patients presented later during the COVID-19 pandemic compared with the same period last year. Because of this, fewer patients were eligible for thrombolysis.

The authors identified 73 patients who were admitted via the acute stroke pathway of Queen Mary Hospital, Hong Kong, during the first 60 days after the first patient was diagnosed with COVID-19 in the country (January 23 to March 24, 2020). In comparison, 89 patients were admitted during the same period in 2019. There were no significant differences in age, sex, vascular risk factors, or stroke severity between the two groups.

The investigators found that the median time from stroke onset to arrival was about 1 hour longer in the 2020 period than in the 2019 period. The proportion of individuals who presented within 4.5 hours was also significantly lower in 2020 (55% vs 72%).

The researchers conclude that "every effort is needed to ensure that acute stroke care is not compromised" during the COVID-19 crisis. "Centralized diversion to protected stroke centers that remain fully operational and informing the public of such system is vital to prevent tragedies of potentially treatable patients with stroke being denied appropriate treatment during this pandemic," they add.

Reduction in Thrombectomy

A fifth study, from France, showed a significant reduction in stroke thrombectomies and an increase in delays to thrombectomy during the COVID-19 crisis.

The study collected national-level data on stroke patients who underwent thrombectomy during a 45-day period during which COVID-19 containment measures were in effect. These data were compared with those of patients who were treated during the same calendar period in 2019. A total of 1513 patients at 32 centers were included. All were in French administrative regions.

Results showed a 21% decrease in thrombectomy case volume during the pandemic period and a significant increase in delays between imaging and groin puncture (144 vs 126 minutes).

The authors conclude: "Solutions in the unprecedented public health emergency are likely to vary locally and regionally but considering alternate or dedicated emergency medical system pathways for (neuro) vascular emergencies may help maintain case volumes and continuity of care."

Stroke. Published online May 20 and May 22, 2020. New York study, Abstract; Chinese study, Abstract; Barcelona study, Abstract; Hong Kong study, Abstract; French study, Abstract

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