Abstract W P351: Plasma Interleukin-6 and C-reactive Protein Are Associated With Acute Diffusion Hyperintensity After Transient Ischemic Attack

Abstract

Background: In suspected TIA, DWI hyperintensity confirms the diagnosis of brain ischemia and identifies those with 3-fold risk of early recurrent stroke. However, immediate MRI is expensive and may not be available in many healthcare settings. A simple validated blood test to objectively support the diagnosis of cerebral ischaemia after transient symptoms might have utility in clinical practice. We hypothesised that blood markers of inflammation may be associated with abnormal DWI following TIA. Methods: BIO-TIA was a multi-centre prospective study of consecutive patients with clinically-defined TIA, confirmed by a stroke physician. Phlebotomy and stroke protocol MRI were performed within 72 hours of symptoms. Patients with malignancy, active infection, trauma, surgery, definite transient non-ischaemic symptoms or recurrent stroke before phlebotomy/MRI were excluded. Plasma high-sensitivity CRP and interleukin-6 (IL-6) were measured by mass spectrometry. Results: In 201 included patients, mean age was 68 years (59% male). Carotid stenosis was present in 26.4% and atrial fibrillation in 29.1%. Mean ABCD2 score was 4.2 (SD 1.3). Acute DWI hyperintensity was observed in 37.8% (76/201). Median hsCRP was 1.78mg/L in DWI-negative, compared with 3.01mg/L in DWI-positive TIA (p=0.04). Median IL-6 was 3.76pg/ml (DWI-negative) versus 4.91pg/ml (DWI-positive) (p=0.04). When the highest quartiles of CRP and IL-6 distributions were compared with quartiles 1-3, the prevalence of DWI hyperintensity was 61.5% (Q4) versus 32.9% (Q1-3) for CRP (p=0.001), and 56.4% (Q4) versus 34.9% [Q1-3) for IL-6 (p=0.02). Thresholds of 4.78mg/L for CRP or 6.21pg/ml for IL-6 had at least 80% specificity for identification of abnormal DWI signal. IL-6 was associated with CRP (rho 0.58), age (rho 0.36), and ABCD2 score (rho 0.18) and carotid stenosis (p≤0.01 for all), but not statin use. Conclusion: Our preliminary findings require validation, but suggest that inexpensive, rapidly-measured blood markers are associated with acute DWI hyperintensity after TIA. If validated, blood markers may have utility to support the diagnosis of cerebral ischemia or select patients for early MRI.