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Introduction: The 5-year recurrence risk after ischaemic stroke and transient ischaemic attack (TIA) is 25–30%. Although inflammation may be a target for prevention trials, the contribution of plaque inflammation to acute cerebrovascular events remains unclear. We investigated the association of acute inflammatory cytokines and high-sensitivity C-reactive protein (CRP) with recently symptomatic carotid atherosclerosis in a prospective cohort study. Methods: Blood and Imaging markers of TIA BIO-TIA) is a multicentre prospective study of imaging and inflammatory markers in patients with TIA. Exclusion criteria were infection and other co-morbid illnesses associated with inflammation. CRP and serum cytokines (interleukin [IL]-6, IL-1β, IL-8, IL-10, IL-12, interferon-γ [IFN-γ] and tumour necrosis factor-α [TNF-α]) were measured. All patients had carotid imaging. Results: Two hundred and thirty-eight TIA cases and 64 controls (TIA mimics) were included. Forty-nine (20.6%) cases had symptomatic internal carotid artery stenosis. Pro-inflammatory cytokine levels increased in a dose-dependent manner across controls, TIA without carotid stenosis (CS), and TIA with CS (IL-1β, ptrend = 0.03; IL-6, ptrend < 0.0001; IL-8, ptrend = 0.01; interferon (IFN)-γ, ptrend = 0.005; TNF-α, ptrend = 0.003). Results were unchanged when DWI-positive cases were excluded. On multivariable linear regression, only age (p = 0.01) and CS (p = 0.04) independently predicted log-IL-6. On multivariable Cox regression, CRP was the only independent predictor of 90-day stroke recurrence (adjusted hazard ratio per 1-unit increase 1.03 [95% CI: 1.01–1.05], p = 0.003). Conclusion: Symptomatic carotid atherosclerosis was associated with elevated cytokines in TIA patients after controlling for other sources of inflammation. High-sensitivity CRP was associated with recurrent ischaemic stroke at 90 days. These findings implicate acute plaque inflammation in the pathogenesis of cerebral thromboembolism and support a rationale for randomized trials of anti-inflammatory therapy for stroke patients, who were excluded from coronary trials.

Background: Prospective population-based studies are important to accurately determine the incidence and characteristics of stroke associated with atrial fibrillation (AF), while avoiding selection bias which may complicate hospital-based studies. Methods: We investigated AF-associated stroke within the North Dublin Population Stroke Study, a prospective cohort study of stroke/transient ischaemic attack in 294,592 individuals, according to recommended criteria for rigorous stroke epidemiological studies. Results: Of 568 stroke patients ascertained in the first year, 31.2% (177/568) were associated with AF (90.4%, i.e. 160/177 ischaemic infarcts). The crude incidence rate of all AF-associated stroke was 60/100,000 person-years (95% CI = 52–70). Prior stroke was almost twice as common in AF compared to non-AF groups (21.9 vs. 12.8%, p = 0.01). The frequency of AF progressively increased across ischaemic stroke patients stratified by increasing stroke severity (NIHSS 0–4, 29.7%; 5–9, 38.1%; 10–14, 43.8%; ≥15, 53.3%, p < 0.0001). The 90-day trajectory of recovery of AF-associated stroke was identical to that of non-AF stroke, but Rankin scores in AF stroke remained higher at 7, 28 and 90 days (p < 0.001 for all). Discussion: AF-associated stroke occurred in one third of all patients and was associated with a distinct profile of recurrent, severe and disabling stroke. Targeted strategies to increase anticoagulation rates may provide a substantial benefit to prevent severe disabling stroke at a population level.