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Carotid Atherosclerosis and Ischemic Stroke Subtypes
Study Questions:
With what ischemic stroke subtypes is carotid artery atherosclerotic disease associated, and how does carotid atherosclerosis mediate the association between cardiovascular risk factors and ischemic stroke subtypes?
Methods:
This is a random sample of 23,973 Chinese participants with no history of cardiovascular disease at enrollment who had carotid ultrasound performed at resurvey after a mean of 8 years. Occurrence of first ischemic stroke was derived largely from insurance records. Strokes were considered lacunar if the associated infarcts were <15 mm in diameter on imaging. Strokes were considered probable cardioembolic if the patient had a hospitalization for ischemic heart disease between enrollment and resurvey or had evidence of probable or definite myocardial infarction (MI) or arrhythmia on resurvey electrocardiogram (ECG). Nonlacunar, noncardioembolic strokes were considered probable large artery strokes.
Results:
A total of 952 patients in the sample had a first ischemic stroke (4.0%). Of these, 263 events (27.6%) were adjudicated as lacunar and 259 (27.2%) were nonlacunar, with the remainder (45.2%) unconfirmed.
Baseline systolic blood pressure (SBP) was more strongly associated with ischemic stroke (odds ratio [OR] per 1 standard deviation [SD] of risk factor, 1.51; 95% confidence interval [CI], 1.42-1.61) than was carotid plaque burden (OR, 1.34; 95% CI, 1.26-1.44). Adjustment for carotid plaque burden did not notably attenuate the association between SBP and ischemic stroke (OR, 1.46; 95% CI, 1.37-1.56). Smoking and diabetes were more weakly associated with ischemic stroke than was carotid plaque burden (ORs 1.11 and 1.08, respectively).
After adjustment for potential confounders, carotid plaque burden was associated with probable large artery stroke (OR per 1 SD of risk factor, 1.39; 95% CI, 1.20-1.62) and lacunar stroke (1.18; 95% CI, 1.02-1.36), but not probable cardioembolic stroke (OR, 1.01; 95% CI, 0.77-1.33).
Conclusions:
Of the major cardiovascular risk factors examined, SBP was most strongly associated with ischemic stroke, and that association was independent of carotid plaque burden. Carotid plaque burden is associated with probable large artery and lacunar stroke subtypes.
Perspective:
The results of this study are not novel and are unlikely to change how stroke providers think about the role of major cardiovascular risk factors and carotid artery disease in stroke subtypes. The stroke subtyping in this study was not based on a validated or widely used categorization system, such as the TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria. Cardioembolic subtyping was performed indirectly (by history of hospital admission for ischemic heart disease between baseline and resurvey or evidence of definite or probable MI or arrhythmia on the ECG at resurvey) and may have resulted in misclassification.
Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Smoking
Keywords: Arrhythmias, Cardiac, Atherosclerosis, Blood Pressure, Brain Ischemia, Carotid Artery Diseases, Coronary Artery Disease, Diabetes Mellitus, Electrocardiography, Myocardial Infarction, Risk Factors, Secondary Prevention, Smoking, Stroke, Stroke, Lacunar, Vascular Diseases
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