Specialized TIA Clinics Linked to Very Low Event Rates

April 21, 2016

Patients treated for a transient ischemic attack (TIA) or minor stroke at specialized TIA units in which urgent evidence-based care is delivered by stroke specialists had a very low risk for stroke and other cardiovascular events over the following year, according to a new study.

The study, published in the April 21 issue of the New England Journal of Medicine, was conducted by a team led by Pierre Amarenco, MD, Bichat Hospital, Paris, France.

The findings come from a program called the TIAregistry.org project, designed to describe the current profile of patients with TIA or minor stroke, as well as risk factors and short- and long-term outcomes and to "refine risk assessment," they write.

"In the TIAregistry.org project, we observed a lower rate of cardiovascular events after a TIA or minor stroke than that in historical cohorts," the authors conclude. "Our findings probably reflect the contemporary risk of recurrent cardiovascular events among patients with a TIA or minor stroke who are admitted to TIA clinics and who receive risk-factor control and antithrombotic treatment as recommended by current guidelines.

"Although we found that the ABCD2 score was a good predictor of risk, our findings suggest that limiting urgent assessment to patients with a score of 4 or more would miss approximately 20% of those with early recurrent strokes. Multiple infarctions on neuroimaging and large-artery atherosclerotic disease were also strong independent predictors of recurrent vascular events," they add. "These results may help in the design and interpretation of future randomized trials."

In an accompanying editorial, Ralph L. Sacco, MD, and Tatjana Rundek, MD, PhD, Miller School of Medicine, University of Miami, Florida, say the study results "support the value of organizing specialized units for the care of patients with a TIA or minor stroke where rapid diagnostic evaluations and evidence-based preventive treatments by stroke specialists can be initiated promptly and lead to reduced early and late risks of stroke."

The researchers report data on 4789 patients from 61 sites, all dedicated to urgent evaluation of patients with TIA in 21 countries as part of the TIAregistry.org.

Of these patients, 78.4% were evaluated by stroke specialists within 24 hours of symptom onset. Acute infarction was found on computed tomography or MRI in 33%, new-onset atrial fibrillation in 5% (67% of whom received anticoagulant therapy before discharge), and carotid stenosis in approximately 16% (27% of whom underwent carotid revascularization before discharge).

The 1-year event rate for composite cardiovascular outcome (stroke, an acute coronary syndrome, or death from cardiovascular causes) was 6.2%. The stroke rates at days 2, 7, 30, 90, and 365 were 1.5%, 2.1%, 2.8%, 3.7%, and 5.1%, respectively — much lower than rates reported in previous studies.

The authors say the low event rates in this study were not explained by a low-risk population. More than two thirds of the cohort had an ABCD2 score of 4 or more, and the risk observed was low in each stratum of the score.

Rather, they suggest that the good outcomes core may be explained by better and faster implementation of secondary stroke prevention strategies, including immediate initiation of antiplatelet drugs, oral anticoagulation in the event of atrial fibrillation, urgent revascularization in patients with critical carotid stenosis, and other secondary prevention measures (such as treatment with statins and blood pressure–lowering drugs).

In their editorial, Dr Sacco and Dr Rundek emphasize that patients with minor stroke or TIA have the least amount of disability and the most to lose should they have a stroke, but they often slip through systems for detecting acute stroke owing either to delay in seeking medical attention or clinicians' assessments that urgent treatment is not needed.

"This lost opportunity is even more worrisome given the tremendous improvements in the quality of primary and secondary stroke prevention," they say.

Urgent Care "Undoubtedly Works"

They note that the outcomes reported in this registry study were at least 50% lower than those reported in previous studies, showing that "urgent care for patients with a TIA or minor stroke either in specialized TIA clinics or dedicated care delivery units with stroke specialists undoubtedly works."

They point out that another important success of the TIAregistry.org project was the excellent adherence rates of self-reported medication use at 3 months and 12 months, which were similar to the rates at discharge.

The study also found some interesting results on risk assessment of patients. In particular, multiple infarctions on brain imaging, large-artery atherosclerosis, and an ABCD2 score of 6 or 7 were each associated with more than a doubling of the risk for stroke. However, limiting urgent assessment to patients with an ABCD2 score of 4 or more would miss approximately 20% of those with early recurrent strokes.

Dr Sacco and Dr Rundek point out that the multiple infarctions observation represent a new finding and may be useful for inclusion in risk-prediction models.

"This study should prompt health care providers and policymakers to make necessary changes in systems of stroke care in order to deliver the most effective care not only to patients with acute stroke, but also to those with a TIA or minor stroke," they conclude.

The study was supported by an unrestricted grant from Sanofi and Bristol-Myers Squibb. Dr Amarenco reports grant support and personal fees from Sanofi and Bristol Myers-Squibb during the conduct of the study; grant support and personal fees from Pfizer; and personal fees from Bayer, Daiichi-Sankyo, Boehringer Ingelheim, Boston Scientific, Medtronic, GlaxoSmithKline, and the Kowa Company outside the submitted work.

N Engl J Med. Published online April 21, 2016. Full text Editorial

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