Residual lipoprotein(a)-associated risk in patients with stroke or transient ischemic attack

Abstract

Background and aims: Lipoprotein (a) [Lp(a)] is a genetically determined risk factor for atherosclerotic cardiovascular diseases. This study aimed to evaluate the association of serum Lp(a) levels with the risk of residual vascular event risk after stroke or transient ischemic attack (TIA) in the Japanese population.

Methods: In this prospective observational study, 533 patients (mean age, 70.7 years; female, 41.8 %) with ischemic stroke (n = 496) or high-risk TIA (n = 37) were consecutively enrolled within 1 week of onset and followed up for 1 year. Patients were divided into 2 groups according to the median baseline Lp(a) levels: (i) low (≤15 mg/dL, n = 270) and (ii) high (>15 mg/dL, n = 263) Lp(a) groups. The primary endpoint was a composite of major adverse cardiovascular events (MACEs), including nonfatal stroke, nonfatal acute coronary syndrome, and vascular death.

Results: Compared to patients with Lp(a) ≤15 mg/dL, those with Lp(a) > 15 mg/dL were more likely to have extracranial carotid artery stenosis (8.8 % versus 15.2 %; p = 0.024) and a history of coronary artery disease (7.8 % versus 14.1 %; p = 0.019). Elevated Lp(a) levels were independently associated with an increased risk of MACE (annual rate, 10.7 % versus 19.1 %; log-rank p = 0.009; adjusted hazard ratio, 1.68; 95 % confidence interval, 1.03-2.72; p = 0.037). When patients were classified according to the etiologic subtype of the index event, elevated Lp(a) was a significant predictor of MACE in patients with atherothrombotic stroke (annual rate, 14.0 % versus 25.8 %; log-rank p = 0.041), but not in those with small vessel disease, cardioembolism, or cryptogenic stroke.

Conclusions: Elevated Lp(a) levels >15 mg/dL in Japanese patients with stroke are associated with extracranial carotid stenosis and a higher risk of MACE. The measurement of Lp(a) levels helped refine the risk assessment of patients with stroke or TIA.

Keywords: Atherosclerosis; Cardiovascular disease; Carotid stenosis; Dyslipidemia; Ischemic stroke; lipoprotein(a).