Rate and Prognosis of Brain Ischemia in Patients With Lower-Risk Transient or Persistent Minor Neurologic Events

Abstract

for the Diagnosis of Uncertain-Origin Benign Transient Neurological Symptoms (DOUBT) Study Group IMPORTANCE Early treatment of patients with transient ischemic attack (TIA) reduces the risk of stroke. However, many patients present with symptoms that have an uncertain diagnosis. Patients with motor, speech, or prolonged symptoms are at the highest risk for recurrent stroke and the most likely to undergo comprehensive investigations. Lower-risk patients are much more likely to be cursorily investigated.OBJECTIVE To establish the frequency of acute infarct defined by diffusion restriction detected on diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) scan (DWI positive). DESIGN, SETTING, AND PARTICIPANTS The Diagnosis of Uncertain-Origin Benign TransientNeurological Symptoms (DOUBT) study was a prospective, observational, international, multicenter cohort study of 1028 patients with low-risk transient or minor symptoms referred to neurology within 8 days of symptom onset. Patients were enrolled between June 1, 2010, and October 31, 2016. Included patients were 40 years or older and had experienced nonmotor or nonspeech minor focal neurologic events of any duration or motor or speech symptoms of short duration (Յ5 minutes), with no previous stroke.EXPOSURES Patients underwent a detailed neurologic assessment prior to undergoing a brain MRI within 8 days of symptom onset. MAIN OUTCOMES AND MEASURES The primary outcome was restricted diffusion on a brain MRI scan (acute stroke).RESULTS A total of 1028 patients (522 women and 506 men; mean [SD] age, 63.0 [11.6] years) were enrolled. A total of 139 patients (13.5%) had an acute stroke as defined by diffusion restriction detected on MRI scans (DWI positive). The final diagnosis was revised in 308 patients (30.0%) after undergoing brain MRI. There were 7 (0.7%) recurrent strokes at 1 year. A DWI-positive brain MRI scan was associated with an increased risk of recurrent stroke (relative risk, 6.4; 95% CI, 2.4-16.8) at 1 year. Absence of a DWI-positive lesion on a brain MRI scan had a 99.8% negative predictive value for recurrent stroke. Factors associated with MRI evidence of stroke in multivariable modeling were older age (odds ratio [OR], 1.02; 95% CI, 1.00-1.04), male sex (OR, 2.03; 95% CI, 1.39-2.96), motor or speech symptoms (OR, 2.12; 95% CI, 1.37-3.29), ongoing symptoms at assessment (OR, 1.97; 95% CI, 1.29-3.02), no prior identical symptomatic event (OR, 1.87; 95% CI, 1.12-3.11), and abnormal results of initial neurologic examination (OR, 1.71; 95% CI, 1.11-2.65). CONCLUSIONS AND RELEVANCEThis study suggested that patients with transient ischemic attack and symptoms traditionally considered low risk carry a substantive risk of acute stroke as defined by diffusion restriction (DWI positive) on a brain MRI scan. Early MRI is required to make a definitive diagnosis.

Delayed Lesions on Diffusion-Weighted Imaging in Initially Lesion-Negative Stroke Patients

“…Various recent studies have shown a poorer prognosis of tissue-positive events compared to that of tissue-negative events, thus contributing to the transition from time-based to tissue-based definitions of AIS and TIA [ 1 , 9 , 11 , 31 , 32 ]. Similarly, we have demonstrated that the positive conversion of DWI lesions is also associated with a higher risk of vascular outcomes.…”

Stroke mimics: incidence, aetiology, clinical features and treatment

“…Abnormalities detected on MRI can be very useful in diagnosis, especially when symptoms are transient, and can be very useful in determining whether the aetiology was ischaemic. The presence of MRI-defined ischaemic lesions in addition to confirmation of diagnosis is associated with a significantly higher risk of future stroke risk [ 17 ]. MRI is however not necessary in the assessment of most stroke mimic patients as the clinical examination and the CT imaging is sufficient to make a firm diagnosis.…”

A predictive analytics model for differentiating between transient ischemic attacks (TIA) and its mimics

“…Although there are few publications and no widely accepted definition for TIA mimics [29,30], our study and other reports suggest that more than 50% of patients who are referred to TIA clinics are in fact TIA mimics [6,7,31]. Given a high estimated incidence rate of TIA in the United States, a high rate of misdiagnosis can be associated with significant cost burden and missed opportunities [32][33][34]. Misdiagnosing patients that are experiencing TIA carries significant costs for both the hospital and the patient [6].…”