Background: Anti-inflammatory therapies reduce recurrent vascular events in coronary disease. Existing studies have reported highly conflicting findings for the association of blood inflammatory markers with vascular recurrence after stroke leading to uncertainty about the potential of anti-inflammatory therapies after stroke and no consensus about the utility of measurement of inflammatory markers in current guidelines. Methods: We investigated the association between hsCRP (high-sensitivity C-reactive protein), IL-6 (interluekin-6), and recurrent major adverse cardiovascular events (MACE), and stroke from individual participant data from 8420 patients with ischemic stroke/transient ischemic attack from 10 prospective studies. We did within-study multivariable regression analyses and then combined adjusted risk ratio (RR) by random-effects meta-analysis. Results: During 18 920 person-years of follow-up, 1407 (16.7% [95% CI, 15.9–17.5]) patients had MACE and 1191 (14.1% [95% CI, 13.4–14.9]) patients had recurrent stroke. On bivariate analysis, baseline IL-6 was associated with MACE (RR, 1.26 [95% CI, 1.10–1.43]) and recurrent stroke (RR, 1.18 [95% CI, 1.05–1.32]), per unit increase log _e IL-6. Similar associations were observed for hsCRP (MACE RR, 1.19 [95% CI, 1.09–1.29]; recurrent stroke RR, 1.12 [95% CI, 1.04–1.21], per unit increase log _e hsCRP). After adjustment for vascular risk factors and treatment, independent associations remained with MACE (IL-6, RR, 1.12 [95% CI, 1.04–1.21]; hsCRP, RR, 1.09 [95% CI, 1.04–1.15]) and recurrent stroke (IL-6, RR, 1.09 [95% CI, 1.00–1.19]; hsCRP, RR, 1.05 [95% CI, 1.00–1.11]). Comparing the top with the bottom quarters (Q4 versus Q1), IL-6 (RR, 1.35 [95% CI, 1.09–1.67]) and hsCRP (RR, 1.31 [95% CI, 1.07–1.61]) were associated with MACE after adjustment. Similar results were observed for recurrent stroke for IL-6 (RR, 1.33 [95% CI, 1.08–1.65]) but not hsCRP (RR, 1.16 [95% CI, 0.93–1.43]). Conclusions: Blood markers of inflammation were independently associated with vascular recurrence after stroke, strengthening the rationale for randomized trials of anti-inflammatory therapies for secondary prevention after ischemic stroke/TIA.

Objective: To determine whether carotid plaque inflammation identified by ¹⁸F-fluorodeoxyglucose (¹⁸FDG)-PET is associated with late (5-year) recurrent stroke. Methods: We did an individual-participant data pooled analysis of three prospective studies with near-identical study methods. Eligible patients had recent non-severe (modified Rankin Score ≤3) ischaemic stroke/TIA and ipsilateral carotid stenosis (50-99%). Participants underwent carotid ¹⁸FDG-PET/CT angiography ≤14 days after recruitment. ¹⁸FDG uptake was expressed as maximum standardized uptake value (SUV_max) in the axial single hottest slice of symptomatic plaque. We calculated the previously-validated Symptomatic Carotid Atheroma Inflammation Lumen-stenosis (SCAIL) score, which incorporates a measure of stenosis severity and ¹⁸FDG uptake. The primary outcome was 5-year recurrent ipsilateral ischaemic stroke after PET imaging. Results: Of 183 eligible patients, 181 patients completed follow-up (98.9%). The median duration of follow-up was 4.9 years (interquartile range 3.3-6.4, cumulative follow-up period 901.8 patient-years). After PET imaging, 17 patients had a recurrent ipsilateral ischemic strokes at 5 years (recurrence rate 9.4%, 95% CI 5.6-14.6%). Baseline plaque SUV_max independently predicted 5-year ipsilateral recurrent stroke after adjustment for age, gender, carotid revascularization, stenosis severity, NIH Stroke Scale, and diabetes mellitus (adjusted HR 1.98; 95 % CI, 1.10-3.56, p=0.02, per 1g/mL increase SUV_max). On multivariable Cox regression, SCAIL score predicted 5-year ipsilateral stroke (adjusted HR 2.73 per 1-point increase; 95% CI 1.52-4.90, p=0.001). Conclusion: Plaque inflammation-related ¹⁸FDG uptake improved identification of 5-year recurrent ipsilateral ischaemic stroke. Addition of plaque inflammation to current selection strategies may target patients most likely to have late as well as early benefit from carotid revascularization. Classification of Evidence: This study provides Class I evidence that in individuals with recent ischemic stroke/TIA and ipsilateral carotid stenosis, carotid plaque inflammation-related ¹⁸FDG uptake on PET/CT angiography was associated with 5-year recurrent ipsilateral stroke.

Importance: Atrial fibrillation (AF) is a leading cause of stroke, and oral anticoagulants (OAC) reduce this risk. However, there are limited data on the residual risk of recurrent stroke in patients with AF.Objective: To determine the recurrent stroke risk in patients with AF by performing a systematic review and meta-analysis.Data Sources: Eligible studies were identified by searching Ovid MEDLINE and Embase from inception (Ovid: January 1946; Embase: January 1970) until January 2025.Study Selection: Eligible studies enrolled patients with prior ischemic stroke and AF, reported information on incidence of recurrent stroke, and had follow-up data for 1 or more years. Three reviewers independently screened abstracts and performed full-text reviews.Data Extraction and Synthesis: Data extraction was performed by 2 reviewers and independently verified by a third. Incidence rates were pooled using random-effects meta-analysis. Analysis was repeated in patients whose qualifying event occurred despite OAC. Study quality was assessed using the Quality In Prognosis Studies tool.Main Outcomes and Measures: The primary outcome was recurrent ischemic stroke. The secondary outcomes were any recurrent stroke (ischemic stroke or intra-cerebral hemorrhage [ICH]) and ICH during follow-up.Results: A total of 23 studies were identified, which included 78 733 patients and 140 307 years of follow-up. The median proportion of OAC use across studies was 92%. The pooled incidence of recurrent ischemic stroke was 3.75% per year (95% CI, 3.17%-4.33%). The risk was higher in noninterventional observational cohorts (4.20% per year; 95% CI, 3.41%-4.99%) compared with randomized clinical trials (2.26% per year; 95% CI, 1.96%-2.57%) (P value for interaction <.001). The risk of any recurrent stroke was 4.88% per year (95% CI, 3.87%-5.90%), and the risk of ICH was 0.58% per year (95% CI, 0.43%-0.73%). In patients with stroke despite OAC, the risk was 7.20% per year (95% CI, 5.05%-9.34%) for ischemic stroke, 8.96% per year (95% CI, 8.25%-9.67%) for any stroke, and 1.40% per year (95% CI, 0.40%-2.40%) for ICH.Conclusions and Relevance: In this systematic review and meta-analysis, even with modern prevention therapy, the residual recurrence risk after AF-related stroke is high, with an estimated 1 in 6 patients experiencing a recurrent ischemic stroke at 5 years. These data demonstrate an urgent need to improve our understanding of the biological processes responsible for recurrence, improve risk stratification, and develop new secondary prevention strategies after AF-related stroke.

Anti-inflammatory therapies reduce major adverse cardiovascular events (MACE) in coronary artery disease but remain unproven after stroke. Establishing the subtype-specific association between inflammatory markers and recurrence risk is essential for optimal selection of patients in randomized trials (RCTs) of anti-inflammatory therapies for secondary stroke prevention. Using individual participant data (IPD) identified from a systematic review, we analyzed the association between high-sensitivity C-reactive protein, interleukin-6 (IL-6), and vascular recurrence after ischemic stroke or transient ischemic attack. The prespecified coprimary end points were (1) any recurrent MACE (first major coronary event, recurrent stroke, or vascular death) and (2) any recurrent stroke (ischemic, hemorrhagic, or unspecified) after sample measurement. Analyses were performed stratified by stroke mechanism, per quarter and per biomarker unit increase after log_e transformation. We then did study-level meta-analysis with comparable published studies not providing IPD. Preferred Reporting Items for Systematic Review and Meta-Analyses IPD guidelines were followed. IPD was obtained from 10 studies (8,420 patients). After adjustment for vascular risk factors and statins/antithrombotic therapy, IL-6 was associated with recurrent MACE in stroke caused by large artery atherosclerosis (LAA) (risk ratio [RR] 2.30, 95% CI 1.21-4.36, p = 0.01), stroke of undetermined cause (UND) (RR 1.78, 1.19-2.66, p = 0.005), and small vessel occlusion (SVO) (RR 1.71, 0.99-2.96, p = 0.053) (quarter 4 [Q4] vs quarter 1 [Q1]). No association was observed for stroke due to cardioembolism or other determined cause. Similar results were seen for recurrent stroke and when analyzed per log_e unit increase for MACE (LAA, RR 1.26 [1.06-1.50], p = 0.009; SVO, RR 1.22 [1.01-1.47], p = 0.04; UND, RR 1.18 [1.04-1.34], p = 0.01). High-sensitivity CRP was associated with recurrent MACE in UND stroke only (Q4 vs Q1 RR 1.45 [1.04-2.03], p = 0.03). Findings were consistent on study-level meta-analysis of the IPD results with 2 other comparable studies (20,136 patients). Our data provide new evidence for the selection of patients in future RCTs of anti-inflammatory therapy in stroke due to large artery atherosclerosis, small vessel occlusion, and undetermined etiology according to inflammatory marker profile.

BACKGROUND: Inflammation promotes atherogenesis. Randomized controlled trials of anti-inflammatory therapies for prevention after stroke have not yet demonstrated clear benefit. IL-6 (interleukin-6) and hsCRP (high-sensitivity C-reactive protein) are independently associated with major adverse cardiovascular events poststroke and may guide patient selection in future randomized controlled trials. Optimal timing of hsCRP/IL-6 measurement poststroke is unknown, as early blood levels may be confounded by the inflammatory response to brain infarction. METHODS: Using individual-participant data from a systematic review, we performed a time-course analysis to investigate the association between hsCRP/IL-6 and recurrent events stratified by timing of sampling. The prespecified coprimary end points after sample measurement were: (1) recurrent major adverse cardiovascular events (first major coronary event, recurrent stroke, or vascular death) and (2) recurrent stroke (ischemic, hemorrhagic, or unspecified). The poststroke dynamics of IL-6/hsCRP were analyzed by plotting their median (interquartile interval) concentrations within each tenth of the sampling timeframe. Acute/postacute phases were defined for each biomarker according to the shape of this relationship. RESULTS: There were data for 9798 patients from 11 studies (19 891 person-years follow-up, 10 observational cohorts, and 1 randomized trial). Each marker was measured once. IL-6 was markedly elevated <24 hours poststroke compared with postacute levels (≥24 hours; 11.6 versus 3.02 pg/mL; P <0.001). HsCRP was elevated for 10 days. IL-6 was associated with recurrent major adverse cardiovascular events in the postacute phase (≥24 hours; risk ratio, 1.30 [CI, 1.19–1.41], per unit log _e IL-6), but not in the acute phase (<24 hours; risk ratio, 1.10 [CI, 0.98–1.25]; P _interaction =0.03). After adjustment for risk factors/medication, the association remained for postacute IL-6 when analyzed per log _e unit (risk ratio, 1.16 [CI, 1.05–1.66]) and per quarter increase (risk ratio, 1.55 [CI, 1.19–2.02]; Q4 versus Q1), but not if measured acutely. Similar findings were observed for recurrent stroke. There was no evidence of time-dependent interaction with hsCRP. CONCLUSIONS: Timing of sample measurement after stroke modifies the association with recurrent major adverse cardiovascular events for IL-6 but not hsCRP. These data inform future randomized controlled trial designs incorporating biomarker-based selection of patients for anti-inflammatory therapies.

Background: For reasons poorly understood, strokes frequently occur in patients with atrial fibrillation (AF) despite oral anticoagulation. Better data are needed to inform randomised trials (RCTs) of new strategies to prevent recurrence in these patients. We investigate the relative contribution of competing stroke mechanisms in patients with AF who have stroke despite anticoagulation (OAC+) compared with those who are anticoagulant naïve (OAC−) at the time of their event. Patients and methods: We performed a cross-sectional study leveraging data from a prospective stroke registry (2015–2022). Eligible patients had ischemic stroke and AF. Stroke classification was performed by a single stroke-specialist blinded to OAC status using TOAST criteria. The presence of atherosclerotic plaque was determined using duplex ultrasonography, computerised tomography (CT) or magnetic resonance (MR) angiography. Imaging was reviewed by a single reader. Logistic regression was used to identify independent predictors of stroke despite anticoagulation. Results: Of 596 patients included, 198 (33.2%) were in the OAC+ group. A competing cause for stroke was more frequent in patients with OAC+ versus OAC− (69/198 (34.8%)) versus 77/398 (19.3%), p < 0.001). After adjustment, both small vessel occlusion (odds ratio (OR): 2.46, 95% CI: 1.20–5.06) and arterial atheroma (⩾50% stenosis) (OR: 1.78, 95% CI: 1.07–2.94) were independently associated with stroke despite anticoagulation. Discussion and conclusion: Patients with AF-associated stroke despite OAC are much more likely than patients who are OAC-naïve to have competing stroke mechanisms. Rigorous investigation for alternative stroke causes in stroke despite OAC has a high diagnostic yield. These data should be used to guide patient selection for future RCTs in this population.