Residual recurrence risk high after AF-related stroke

Approximately one in six atrial fibrillation (AF) patients who sustained a stroke experiences another one within 5 years despite receiving modern preventive therapy, according to a systematic review and meta-analysis.

Researchers searched online databases for studies involving patients with AF and prior ischaemic stroke, had data on the incidence of recurrent stroke, and had a follow-up duration of at least 1 year. Recurrent ischaemic stroke was the primary outcome. Secondary outcomes included any recurrent stroke (ischaemic stroke or intra-cerebral haemorrhage [ICH]) and ICH during follow-up.

Random-effects meta-analysis was used to pool the incidence rates, with analysis repeated in patients whose qualifying event occurred despite use of an oral anticoagulant (OAC). The Quality In Prognosis Studies tool facilitated assessment of study quality.

A total of 23 studies met the eligibility criteria and were included in the meta-analysis. These studies involved 78,733 patients, with 140,307 years of follow-up. The median percentage of patients who used OAC across studies was 92 percent.

The pooled incidence of recurrent ischaemic stroke was 3.75 percent per year (95 percent confidence interval [CI], 3.17–4.33). The incidence was higher in noninterventional observational cohorts (4.20 percent per year, 95 percent CI, 3.41–4.99) than in randomized clinical trials (2.26 percent per year, 95 percent CI, 1.96–2.57; p<0.001 for interaction).

Meanwhile, the pooled incidence of any recurrent stroke was 4.88 percent per year (95 percent CI, 3.87–5.90), while that of ICH was 0.58 percent per year (95 percent CI, 0.43–0.73).

Among patients with stroke despite OAC use, the incidence of ischaemic stroke was 7.20 percent per year (95 percent CI, 5.05–9.34), while those of any stroke and ICH were 8.96 percent per year (95 percent CI, 8.25–9.67) and 1.40 percent per year (95 percent CI, 0.40–2.40), respectively.

The findings point to an urgent need to further understand the biological processes responsible for recurrence, improve risk stratification, and develop new secondary prevention strategies after AF-related stroke, the researchers said.