Somatic mutation contributing to clonal haematopoiesis is a risk factor of recurrent stroke in first-ever acute ischaemic stroke: a prospective cohort study.

Background: Somatic mutation contributes to clonal haematopoiesis of indeterminate potential (CHIP) is related to age and associated with a higher risk of stroke and atherosclerotic cardiovascular disease. Here, we investigated the prognostic significance of CHIP in a large first-ever acute ischaemic stroke (AIS) cohort and explored the underlying mechanisms.

Methods: We studied a prospective cohort of 6016 patients who had a first-ever AIS in China. Whole-genome sequencing was performed to identify CHIP. High-sensitivity C reactive protein (hs-CRP) levels above 3 mg/L at baseline were defined as hyperinflammation. Recurrent stroke during the 3-month follow-up was the primary outcome.

Results: Among the 6016 patients who had a first-ever AIS, with a median age was 62 years (IQR, 54.0‒70.0), 3.70% were identified as CHIP carriers. The most common mutations occurred in the DNMT3A (30.0%) and TET2 (11.4%) genes. During a follow-up of 3 months, the presence of CHIP was associated with recurrent stroke (HR 1.62, 95% CI 1.04 to 2.51, p=0.03), recurrent ischaemic stroke (HR 1.64, 95% CI 1.04 to 2.58, p=0.03) and combined vascular events (HR 1.58, 95% CI 1.02 to 2.44, p=0.04) after adjusting for hsCRP levels at baseline in patients who had a first-ever AIS. Subgroup analysis demonstrated that CHIP was only associated with recurrent stroke when patients under hyperinflammation (OR 3.10, 95% CI 1.92 to 5.00, p<0.001) but not in those without hyperinflammation (OR 0.18, 95% CI 0.03 to 1.04, p=0.06, P_interaction=0.002).

Conclusion: Our results suggest that somatic mutations contributing to CHIP increase the risk of short-term recurrent stroke in patients who had a first-ever AIS. Hyperinflammation may be important in the relationship between CHIP and recurrent stroke.