Risk Score Refines TIA Management for PCPs, Emergency Docs

Marilynn Larkin

October 20, 2022

The authors of a new evidence review recommend the Canadian TIA Risk Score for managing patients who present to the emergency department or physician's office with an apparent transient ischemic attack (TIA) or minor stroke.

Dr Jeffery Perry

"Many hospitals do not have enough stroke neurologists to see every patient with TIA or minor stroke within 24 hours. Likewise, many emergency departments around the world are stretched beyond capacity," study author Jeffery J. Perry, MD, senior scientist at the Ottawa Hospital Research Institute, told Medscape Medical News.

"This review corresponds to most of the recommendations by the American Heart Association and the Canadian Stroke Best Practice Recommendations," he said. "It does, however, go further to differentiate high-risk vs low-risk patients for subsequent stroke using the Canadian TIA Score and offers practical suggestions for how to provide high-quality care in environments without the capacity to provide immediate vascular imaging, immediate MRI scanning, and immediate stroke specialist assessments."

Most patients at low risk of a subsequent stroke (that is, patients with <1% risk for a subsequent stroke at 7 days) can be managed safely as outpatients without causing delays in their departure for vascular imaging or neurology consultation during their initial emergency department visits, Perry added. "The Canadian TIA Score can be used to determine the urgency for an assessment by a stroke neurologist."

The study was published October 11 in CMAJ.

Score Stratifies Risk

Perry, lead author of the Canadian TIA Score validation study, said that the CMAJ editorial board approached him to write the review and to incorporate the new score into the latest recommendations. To include the latest evidence, Perry and colleagues reviewed the most recent position statements on TIA and minor stroke management and searched the literature for relevant articles. They note that the nomenclature related to TIA and minor stroke is inconsistent, that it's not necessary to differentiate between the two from a clinical standpoint, and that the term "acute ischemic cerebrovascular syndrome" has been proposed to include both.

Broadly, the team's recommended strategy for the diagnosis and management of the condition includes the following steps:

  1. Diagnosis: Sudden loss of motor function and impaired speech are strong indicators; symptoms tend to be negative (eg, loss of vision rather than flashing lights).

  2. Risk assessment: Use of the Canadian TIA Score to stratify 7-day stroke risk (low risk: <1%, medium risk: 1% to 5%, high risk: >5%).

  3. Investigations: Urgent CT within 48 hours; vascular imaging to identify acutely symptomatic carotid stenosis in medium- to high-risk patients, as determined on the basis of the TIA score; ECG to identify atrial fibrillation or flutter and to optimize anticoagulant use; if the index of suspicion is high, echocardiography should be employed to look for cardioembolic sources.

  4. Management: Dual antiplatelet therapy for 21 days in medium- and high-risk patients; hypertension should be managed; patients should be referred for stroke clinic assessment; aggressive lifestyle changes should be initiated to lower lipid levels.

"I believe that our recommendations should be incorporated with the clinical guidelines," said Perry.

Caveats and Concerns

Commenting on the article for Medscape, Steven M. Greenberg, MD, PhD, vice chair for faculty development of the Department of Neurology at Massachusetts General Hospital in Boston and a professor of neurology at Harvard Medical School, said, "Although the proposed guidelines are broadly evidence-based and consistent with standard of care, there are several areas where stroke specialists might disagree and suggest alternative strategies." Greenberg was not involved in the study.

Dr Steven Greenberg

While some lower-risk features, such as repetitive or stereotyped symptoms or vertigo, can be more suggestive of TIA mimics, he said that "these features need to be scrutinized quite carefully. Critical carotid stenosis, for example, can give rise to brief, repetitive, stereotyped low-flow TIAs that require urgent revascularization."

Vertigo might be a feature of brainstem or cerebellar TIA or minor stroke, said Greenberg, especially in the setting of other posterior circulation symptoms. Validated guidelines for differentiating peripheral vertigo and CNS vertigo are available, he noted.

"Another caveat is that the studies demonstrating benefit of brief dual antiplatelet therapy following acute TIA or minor stroke were based on ABCD2 rather than the Canadian TIA score," he said. "It is therefore important for any score-based recommendations to be applied in the overall context of existing stroke prevention guidelines."

In addition to the recommendation for urgent vascular imaging of patients whose presentations suggest bona fide TIA or minor stroke, most guidelines also recommend extended cardiac monitoring and transthoracic ECG to identify potential sources of embolism, Greenberg added. "Users of these guidelines should also be aware of the limited yield of head CT, which is able to detect some old strokes, large acute strokes — presumably not relevant to patients presenting with TIA or minor stroke — and acute intracranial hemorrhages."

Louis R. Caplan, MD, founder of the Harvard Stroke Registry at Beth Israel Deaconess Medical Center in Boston and a professor of neurology at Harvard Medical School, also commented on the study for Medscape.

While the review "is okay for care by nonstroke specialists, ideally, major referral centers could have a TIA or stroke clinic, as is present in much of Western Europe," he said. This would allow the stroke etiology to be investigated for each patient.

"Many patients can be treated with the regimen outlined by the authors, but some with other conditions, such as atrial cardiopathy, patent foramen ovale, atrial myxoma, thrombus within the cardiac ventricle or atrium, will require anticoagulants," he noted. "Thrombolysis and mechanical thrombectomy would be considered in some. Each stroke patient is different, and management cannot be homogenized into one remedy. One size does not fit all."

In an accompanying commentary, Shelagh B. Coutts, MD, and Michael D. Hill, MD, both of the University of Calgary, presented their team's approach to the acute management of patients with likely cerebral ischemia. Such management includes risk assessment and stratification by clinical symptoms, rather than a particular score. They also typically conduct CT angiography. "If the CTA is completely normal (ie, no occlusion, no atherosclerosis or arterial dissection and no other vascular abnormality), we rely on the high negative predictive value of this result and discharge the patient home on antiplatelet treatment with outpatient follow-up, including MRI of the brain (since CT cannot reliably rule out minor ischemia) within the first week," they write.

The review was conducted without commercial funding. Perry, Greenberg, Caplan, Coutts, and Hill have disclosed no relevant financial relationships.

CMAJ. Published online October 11, 2022. Full text

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