July 2023

Call to action on residual stroke risk

Prof. Jean-Charles Fruchart, Prof. Michel Hermans, Prof. Pierre Amarenco

Stroke is the leading cause of disability worldwide and the second leading cause of death. According to latest data from the Global Burden of Disease Study, the absolute number of strokes has increased by 70% over the last three decades (1990 to 2019), with an even higher increase among those aged over 70 years ¹. Additionally, there are sex disparities in stroke epidemiology. While men are at higher risk of stroke throughout most of their life, the incidence of stroke in women increases with age, especially after 85 years. Given their longer life expectancy, women therefore account for a larger proportion of stroke morbidity and mortality, despite advances that have been made in therapeutic management ². Thus, the high global burden of stroke and associated disability– increasing as populations age – merits renewed focus on preventive management.

This call to action also applies to the management of transient ischaemic attack (TIA) or minor stroke. Recent data from the TIA registry, an international, prospective, observational registry of patients with a recent (within the previous 7 days) TIA or minor ischaemic stroke highlights the challenge of managing residual stroke risk. Five years after a TIA or minor stroke, these patients have a substantial burden of disability largely predicted by modifiable risk factors. Notably, among those with concomitant diabetes, the risk of recurrent disabling or fatal stroke was more than doubled ³. Furthermore, patients with pre-existing atherosclerosis were at much higher risk (by 2-3-fold) of major vascular events within 5 years than those without atherosclerosis ⁴.

To some extent, action to reduce residual stroke risk is hampered by the paucity of clinical trials, as highlighted by Professor Pierre Amarenco at the recent International Steering Committee Meeting of the Residual Risk Reduction Initiative in Marrakech, Morocco in February this year. Despite this, there are important lessons to be gained from the landmark studies that have been conducted. The Treat Stroke to Target (TST) study showed that substantial lowering of low-density lipoprotein cholesterol (LDL-C), both in terms of the target value and the magnitude of LDL-C reduction, was important (5-7). Targeting atherogenic dyslipidemia – the combination of elevated triglycerides and low plasma high-density lipoprotein cholesterol which is prevalent in diabetes – may offer additional benefit; in the TST trial, patients with stroke, atherosclerosis and atherogenic dyslipidemia obtained a 36% risk reduction in the primary outcome ⁵.