A randomized parallel-group trial comparing intensive LDL-C lowering to modest lowering for prevention of major adverse cardiovascular events (MACE) in patients with recent ischemic stroke in the setting of atherosclerosis has shown that an aggressive LDL-C reduction strategy with a goal of < 70mg/dl is superior to modest reduction approach which targets a range of 90-110 mg/dl.
Results of the Treat Stroke to Target Trial (TST trial) which enrolled 2860 patients (32% females) with a median follow-up of 3.5 years were presented by Dr. Amarenco (Department of Neurology and Stroke Center, Bichat Hospital, France) at AHA 2019 and simultaneously published in The New England Journal of Medicine.
Patients with established atherosclerotic cardiovascular disease (ASCVD) and ischemic stroke within the past 3 months or transient ischemic stroke (TIA) within the past 15 days (modified Rankin score of 0-3) were randomized in 1:1 fashion to statin therapy with either a goal LDL-C of < 70 mg/dl (n =1430) or 90-110 mg/dl (n = 1430).
The primary efficacy endpoint of the trial was composite of MACE (nonfatal cerebral infarction or stroke of undetermined origin, nonfatal myocardial infarction, hospitalization for unstable angina followed by urgent coronary-artery revascularization, TIA treated with urgent carotid revascularization, or CV death). The primary outcome occurred in 8.5% of patients assigned to the group with intensive LDL lowering compared to 10.9% of patients in the modest control approach (adjusted hazard ratio, 0.78; 95% confidence interval [CI], 0.61 to 0.98; P=0.04). Mean LDL-C levels at baseline were 135 mg/dl for both groups and at 3.5 years for the intensive vs. modest treatment groups were 65 vs. 96 mg/dl (p < 0.05). Secondary outcomes were occurrence of MI, need for urgent revascularization, all-cause mortality, intracranial hemorrhage, and newly diagnosed diabetes mellitus. Rates of intracranial hemorrhage (1.3% vs. 0.9% [p > 0.05]) and new-onset diabetes mellitus (7.2% vs. 5.7% [p > 0.05]) were numerically higher with more aggressive control, but not statistically significant.
The present study highlights the clinical benefit obtained by a tighter control of plasma LDL levels for secondary prevention of stroke. Previously, the SPARCL trial showed that in patients who have had a stroke within the prior one to six months without coronary artery disease, treatment with 80 mg atorvastatin led to a lower incidence of recurrent MACE including fatal and nonfatal strokes. In the Heart Protection Study (HPS), simvastatin 40mg did not show benefit in secondary stroke protection, but in HPS, patients were enrolled after a mean of 4.3 years of having a cerebrovascular accident, whereas the greatest risk for recurrent strokes resides within the first year of suffering from a cerebrovascular accident. Though findings from the current TST trial are in line with the SPARCL trial in terms of reduction of recurrent MACE, the SPARCL trial saw an increase in the incidence of hemorrhagic strokes in the treatment arm, while the present TST clinical trial revealed no rise in hemorrhagic stroke rates in patients despite achieving more aggressive reductions in their serum LDL-C levels.
The authors ask the readers to interpret the results of the TST trial while considering the fact that the study was stopped prematurely due to insufficient funding at 3.5 years and did not reach the goal of 385 events, instead, 277 primary events were recorded for the analysis. In addition, secondary endpoints could not be tested due to the failure of hierarchical clustering of endpoints.