Abstract 3932: High Rate Of Radiographic Stroke Recurrence In Cryptogenic TIA And Minor Stroke Patients: A Prospective Imaging Study
Introduction: Cryptogenic stroke (CS) mechanism in patients with TIA/Minor stroke has a recurrent stroke risk of 1-6% within 3 months. There is some evidence to suggest that an occult embolic phenomenon would be a likely cause of stroke in many patients with CS. It is likely that radiographic event rates are higher than clinical event rates which may potentially be a therapeutic target for proof of concept prevention trials. We sought to determine clinical and radiographic event rates in patients with cryptogenic mechanisms in a TIA/minor stroke population.
Methods: Patients with TIA/Minor stroke (NIH Stroke Scale ≤ 3) were prospectively enrolled and imaged within 24 hours of symptom onset as part of two prospective imaging cohorts. [VISION (V) and CATCH (C)]. Patients were included if their baseline modified Rankin scale (mRS) was ≤1. All patients were followed clinically for 3 months to document any clinical recurrence and had a repeat MRI either at day 30 (V) or at day 90 (C). Stroke mechanisms were categorized as per TOAST criteria after parenchymal and vascular imaging and cardiac investigations. Patients were labelled as cryptogenic only after standard etiological workup for ischemic stroke including at least vascular imaging, transthoracic echocardiogram and holter monitoring was completed. Follow up imaging was assessed for any new lesions in comparison to baseline imaging.
Results: Among patients enrolled in both prospective studies 380/844(45%) had cryptogenic stroke mechanisms. Of these, 215 patients had follow up imaging. There were 132 (61%) males. Intracranial occlusions was seen in 23/215 (10.6%) with baseline DWI abnormality documented in 66/215 (30.6%). In the VISION dataset, 5/76 (6.6%, 95%CI 2.2-15%) patients had new lesions on follow-up MRI at day 30. In the CATCH dataset 19/131 (14.5%: 9-22%) of patients had new lesions on follow-up MRI at day 90. Baseline DWI abnormalities was a significant predictor of new radiological lesions on follow-up imaging [p=0.003 OR 4.75 95% CI: 1.67-13.2]. Overall clinical recurrence was seen in 10/215 (4.6%: 2.2-8.4%) of patients. Baseline DWI abnormality was not a significant predictor of clinical recurrence (p=0.96).
Conclusion: TIA/Minor stroke patients with cryptogenic mechanism show evidence of silent radiological accumulation of disease on follow up imaging at a higher rate than clinical recurrence. Repeat brain imaging at 3 months or potentially later may be a useful surrogate marker for disease activity in treatment trials in this population. There is a need for randomized controlled trials using novel anticoagulants with follow-up imaging as a surrogate marker of disease activity to improve treatment of cryptogenic minor stroke/TIA.
- © 2012 by American Heart Association, Inc.