Introduction: Although white matter hyperintensities (WMH) on brain MRIs are associated with common vascular risk factors, the mechanisms underlying progression of WMH are still poorly understood.
Hypothesis: We aim to investigate the association between common vascular risk factors and the severity of WMH according to the subtypes of ischemic stroke.
Methods: Consecutive patients admitted due to ischemic stroke or TIA were included (n=841). Large artery disease (LAD) and small vessel occlusion (SVO) were defined according to the SSS-TOAST classification. WMH were categorized into two groups: no/mild and moderate/severe using Fazekas scale. Demographics, vascular risk factors and laboratory results were compared between the two groups (LAD vs SVO) in total and separately.
Results: A total of 228 patients who underwent brain MRI within seven days after onset were eligible (n=170 in LAD, n=58 in SVO). Patients with LAD were older than those with SVO (mean age 67 years vs. 60 years, p<0.001), but the proportion of patients with moderate/severe WMH did not significantly differ between the two groups (28.2% vs 29.3%, p=0.876). Older age and hypertension were independent risk factors of moderate/severe WMH (OR=3.94 [2.46-6.30] with an increased age of 10 years; OR=5.14 [1.70-15.56], P=0.004 for hypertension) after adjustment of common cardiovascular risk factors. In patients with LAD, independent risk factors of moderate/severe WMH were age (OR=3.86 [1.83-8.12] for every ten-year increase, P<0.001) and hypertension (OR=5.64 [1.51-21.1], P=0.01). On the other hand, age was the only independent risk factor in patients with SVO (OR=3.03 [1.28-7.19] for every ten-year increase, P=0.012).
Conclusion: In conclusion, this study showed that there is a different association between hypertension and severity of WMH in each stroke subtype. Other potential mechanisms of WMH, those not associated with traditional vascular risk factors, may be associated with progression of WMH.