Carotid Atherosclerosis Evolution When Targeting a Low-Density Lipoprotein Cholesterol Concentration

Abstract

The TST trial (Treat Stroke to Target) showed the benefit of targeting a low-density lipoprotein cholesterol (LDL-C) concentration of <70 mg/dL in terms of reducing the risk of major cardiovascular events in 2860 patients with ischemic stroke with atherosclerotic stenosis of cerebral vasculature. The impact on carotid atherosclerosis evolution is not known. TST-PLUS (Treat Stroke to Target-Plaque Ultrasound Study) included 201 patients assigned to an LDL-C concentration of <70 mg/dL and 212 patients assigned to a target of 100±10 mg/dL. To achieve these goals, investigators used the statin and dosage of their choice and added ezetimibe as needed. Ultrasonographers were certified and carotid ultrasound examinations were performed using M'Ath software at baseline and at 2, 3, and 5 years. All images were uploaded to the Intelligence in Medical Technologies database directly from the carotid ultrasound device. The central core laboratory performed all offline measurements of the intima-media thickness of both common carotid arteries blinded from the randomization arm. The main outcomes were newly diagnosed atherosclerotic plaque on carotid bifurcation or internal carotid artery using the Mannheim consensus definition and between-group comparison of common carotid arteries intima-media thickness change. After a median follow-up of 3.1 years, the achieved LDL-C concentrations were 64 mg/dL (1.64 mmol/L) in the lower-target group and 106 mg/dL (2.72 mmol/L) in the higher-target group. Compared with the higher-target group, patients in the lower-target group had a similar incidence of newly diagnosed carotid plaque: 46/201 (5-year rate, 26.1%) versus 45/212 (5-year rate, 29.7%). The change in common carotid arteries intima-media thickness was -2.69 µm (95% CI, -6.55 to 1.18) in the higher-target group and -10.53 µm (95% CI, -14.21 to -6.85) in the lower-target group, resulting in an absolute between-group difference of -7.84 µm (95% CI, -13.18 to -2.51; P=0.004). In patients with ischemic stroke and atherosclerosis, an LDL-C target of <70 mg/dL (1.8 mmol/L) did not reduce the incidence of new carotid plaques but produced significantly greater regression of carotid atherosclerosis than an LDL-C target of 90 to 110 mg/dL. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01252875.