A wealth of data supports the use of cholesterol-lowering statin medications for secondary prevention in patients with myocardial infarction. Patients in these trials have demonstrated not only a reduction in secondary cardiovascular events, but also a decreased risk of subsequent stroke and transient ischemic attack (TIA) in subgroup analyses. However, it still remains unclear if initiation of a statin after initial stroke or TIA will effectively prevent secondary cerebrovascular events. A recently published large trial attempted to address this issue and guide clinicians who are considering statin therapy in their patients who present with stroke or TIA.
The Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial enrolled 4731 adults who suffered an ischemic or hemorrhagic stroke or TIA, diagnosed by a neurologist, one to six months prior to study entry. Patients with atrial fibrillation or proven cardiac sources of embolus were excluded, hoping to focus on a more atherosclerotic stroke population. Patients with known coronary heart disease were also excluded. Patients with an LDL level at baseline of 100 to 190 mg/dL were randomized in a double-blind fashion to 80 mg of atorvastatin daily or placebo with a primary end point of nonfatal or fatal stroke. The two study groups had similar LDL levels at study entry and did not have significant differences in their use of antiplatelet medications, antihypertensives, or warfarin throughout the course of the trial.
After a median follow up of nearly 5 years, the atorvastatin group demonstrated a 16.0% relative reduction in risk of subsequent nonfatal or fatal stroke (hazard ratio, 0.84; CI, 95%, interval, 0.71 to 0.99; p = .03). The number needed to treat with atorvastatin for 5 years to prevent one recurrent stroke was 46 patients (CI, 95%: 24 to 243 patients). Secondary end point analysis revealed a significant reduction in the combined risk of stroke and TIA (hazard ratio, 0.77; CI, 95%, interval, 0.67 to 0.88; p < .001) as well as in cardiovascular events such as myocardial infarction. There were no significant mortality differences between the two groups.
The number of patients in each group lost to follow up was similar as were the rates of serious adverse events. There were only five cases of rhabdomyolysis in the trial, and three occurred in patients assigned to the placebo group. Persistent transaminase elevation (defined as greater than three times normal) was more frequent in the statin group than in the placebo group (2.2% versus 0.5%, p < .001), but there were no episodes of liver failure observed in any of the patients in the trial.
Of the 88 patients experiencing at least one hemorrhagic stroke during the study, 55 were in the statin group and 33 were in the placebo group. Although this trial was not powered adequately to detect a difference in hemorrhage rates, these results agree with some previous studies that have revealed an increase in hemorrhagic stroke in patients with low LDL levels on statin therapy.
This well-designed randomized trial demonstrates that treating stroke or TIA patients with high-dose atorvastatin reduces the risk of recurrent stroke or TIA. The study population was limited to patients without known coronary artery disease and with baseline LDL levels of 100 to 190 mg/dL. The data support the view of stroke and TIA as coronary heart disease equivalents necessitating appropriate aggressive treatment of atherosclerotic risk factors such as hypercholesterolemia.
A few questions remain for clinicians deciding how best to treat patients with stroke and TIA. First, the dose and type of statin used in this trial was extremely high, and it is not clear if lower doses or alternative statin medications would have the same effect. Second, the relationship between low LDL levels and hemorrhagic stroke remains unclear. It is possible that statins alone or their lipid-lowering effects increase the risk of hemorrhagic stroke in some patients; until this is studied further, patients with hemorrhagic stroke should perhaps not have their LDL levels lowered to extremely low values, and they might not be ideal candidates for high-dose statin therapy. Finally, although the adverse event profile in this study was favorable in the treatment group, concerns regarding statin-induced myopathy and neuropathy remain, especially when statins are given at these high doses. Despite these limitations, this important study likely will change practice and now makes initiation of statin therapy standard-of-care in most patients with stroke or TIA.