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Speed is of the utmost importance when dealing with patients having a stroke. But it is also of importance in patients having a TIA (transient ischemic attack). The risk of stroke is especially high within the first 48 hours following a TIA. Hence, prompt evaluation and implementation of measures to prevent stroke is essential when confronted with a patient having a TIA.
Of patients presenting to an emergency department with TIA, 5.3% had a stroke during the first 2 days, and 10.5% within 90 days of TIA presentation (Johnston 2000). Another study (Lovett 2003) found that, of patients with a first-ever TIA, the risk of stroke was 8.6% at 7 days and 12.0% at 30 days
A systematic review and meta-analysis showed the rate of subsequent ischemic stroke after TIA was estimated to be 2.4% within 2 days, 3.8% within 7 days, 4.1% within 30 days, and 4.7% within 90 days (Shahjouei 2021).
The Framingham Heart Study showed that after TIA, 21.5% of strokes occurred within 7 days, 30.8% within 30 days, 39.2% within 90 days, and 48.5% more than 1 year after the index TIA (Lioutas 2021).
Studies have shown up to an 80% reduction in the risk of stroke after a TIA with early implementation of secondary stroke prevention strategies (Shahjouei 2022). Therefore, it is incumbent upon us to get the evaluation of the TIA patient completed as soon as possible following the TIA. In the past, most such evaluations were done in the emergency department or hospital. But in recent years we have had a push to get that evaluation done promptly on an outpatient basis in “TIA clinics”.
There has always been some concern about doing that evaluation as an outpatient. So, recently, Shahjouei and colleagues (Shahjouei 2022) did a systematic review and meta-analysis of studies on the risk of subsequent stroke among patients receiving outpatient vs inpatient care for TIA.
Among the patients who were treated at a TIA clinic, the risk of subsequent stroke following a TIA or minor ischemic stroke was 0.3% within 2 days, 1.0% within 7 days, 1.3% within 30 days, and 2.1% within 90 days. Among the patients who were treated as inpatients, the risk of subsequent stroke was to 0.5% within 2 days, 1.2% within 7 days, 1.6% within 30 days, and 2.8% (95% CI, 2.1%-3.5%) within 90 days. For those seen in the ED’s, the risk was 1.9% within 2 days, 3.4% within 7 days, 3.5% within 30 days, and 3.5% within 90 days. The risk of stroke among patients treated at TIA clinics was not significantly different from those hospitalized.
The authors conclude that the risk of subsequent stroke among patients who were evaluated in a TIA clinic was not higher than those hospitalized. Patients who received treatment in ED’s without further follow-up had a higher risk of subsequent stroke. These findings suggest that TIA clinics can be an effective component of the TIA care component pathway.
Note, however, that patients seen in TIA clinics tended to be younger and had lower ABCD2 scores. Many guidelines suggest that higher risk patients with TIA, such as those with higher ABCD2 scores, be evaluated as inpatients.
The authors also note that many patients seen in the ED may not have formal neurological consulations. They note that the percentage of TIA misdiagnosis can be as high as 60% in ED’s and primary care offices. They also note that “TIA mimics” (eg. migraine aura) may be misdiagnosed as TIA’s in such patients.
Overall, the Shahjouei meta-analysis is reassuring that the outcomes of TIA patients evaluated at TIA clinics are at least as good as those of hospitalized TIA patients, and may be even better than those of patients evaluated in the ED without designated followup. But any TIA clinic must be staffed by neurologists (or other provider with equivalent neurological training) and have ready access to ultrasound, imaging, and cardiac tools. And followup is essesntial for appropriate management of stroke risk factors, and compliance with more recent recommendations for antiplatelet therapy.
Johnston SC, Gress DR, Browner WS, Sidney S. Short-term prognosis after emergency department diagnosis of TIA. JAMA 2000; 284: 2901-2906
Lovett JK, Dennis MS, Sandercock PAG, et al. Very Early Risk of Stroke After a First Transient Ischemic Attack. Stroke 2003; 34: e138-e140
Shahjouei S, Sadighi A, Chaudhary D, et al. A 5-Decade Analysis of Incidence Trends of Ischemic Stroke After Transient Ischemic Attack: A Systematic Review and Meta-analysis. JAMA Neurol 2021; 78(1): 77=87
Lioutas V, Ivan CS, Himali JJ, et al. Incidence of Transient Ischemic Attack and Association With Long-term Risk of Stroke. JAMA 2021; 325(4): 373-381
Shahjouei S, Li J, Koza E, et al. Risk of Subsequent Stroke Among Patients Receiving Outpatient vs Inpatient Care for Transient Ischemic Attack: A Systematic Review and Meta-analysis. JAMA Netw Open 2022; 5(1): e2136644
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