French Cohort Data from TST Trial Details Benefit of Lower LDL-C Target

Pierre Amarenco, MD

New data from the Treat Stroke to Target (TST) trial presented at the American Stroke Association’s International Stroke Conference (ISC) 2020 is shedding further light on the impact a target LDL-C of less than 70 mg/dL can have in Caucasian patients.

Data from the French cohort of the trial, which included more than 2500 patients, indicated a target LDL-C of less than 70 mg/dL after an ischemic stroke of atherosclerotic origin could prevent 1 in 4 major vascular events in a Caucasian population.

The TST trial, which was presented at AHA 2019, was a multicenter trial that randomized 2860 patients who recently experienced an atherothrombotic ischemic stroke in the past 3 months or transient ischemic attack (TIA) in 1:1 ratio to an LDL-C target of less than 70 mg/dL or an LDL of 100±10 mg/dL using statins or ezetimibe. The French cohort data presented at ISC 20 examined 1073 patients with a follow-up of 5.3 years, which was almost 2 years more than the 3.5 years of follow-up from the AHA 2019 presentation.

The trial had a composite endpoint of nonfatal ischemic stroke or myocardial infarction, news symptoms requiring urgent coronary or carotid revascularization, and vascular death. In the entire TST study cohort, the endpoint was achieved in 8.5% of patients in those with a target of less than 70 mg/dL and in 10.9% in the 100±10 mg/dL group (HR 0.78, 95% CI, 0.61-0.98; P = .036).

Of the 2860 patients, 1073 were randomized to a target of less than 70 mg/dL and 1075 were randomized to the 100±10 mg/dL group—mean LDL-C achieved after a median 5.3 years of follow-up was 66 mg/dL and 96 mg/dL, respectively. In the entire TST cohort, the mean LDL-C achieved for the groups was 65 mg/dL and 96 mg/dL.

In the French cohort, the primary outcome occurred in 9.6% of patients in the lower target group and 12.9% of patients in the 100±10 mg/dL group (HR 0.74, 95% CI, 0.75-0.94; P = .019). Investigators also pointed out cerebral infarction and urgent carotid revascularization following TIA was reduced by 27% (P = .046) and cerebral infarction or intracranial hemorrhage was reduced by 28% (P = .023) in patients with a target of less than 70 mg/dL.

When examining the primary outcome or intracranial hemorrhage, results indicated a 25% in these type of events (P = .022). An association was observed between a lower target LDL-C and intracranial hemorrhages—with 13 patients experiencing such an event in the lower target group versus 11 patients in the higher target group (HR 1.17, 95% CI, 0.53-2.62, P = .70). This is similar to an effect seen in the entire TST cohort (1.3% versus 0.9%; HR 1.38, 95% CI 0.68-2.82).

Results of an NNT analysis indicated a target LDL-C of less than 70 mg/dL avoided 1 subsequent major vascular event in 4 (NNT=30) in a Caucasian population.

This study, titled “Benefit of Targeting a LDL Cholesterol Less than 70 mg/dL after an Ischemic Stroke of Atherosclerotic Origin. The 5-year Results of the French Part of the TST Trial,” was presented at ISC 20.