Even small brain lesions may increase mortality in patients without prior stroke history
Clinicians may want to reconsider the practice of dismissing very small cerebral lesions found on MRI, study authors said.
Having even very small (<3 mm) brain lesions may triple the risk for stroke and death in asymptomatic patients with no history of stroke, and having both very small and larger lesions may increase the risk 8-fold, a study found.
To determine the association between lesion size and incident stroke, stroke-related mortality, and all-cause mortality, researchers examined MRI data from 1993 to 1995 for 2,892 adults from 2 Atherosclerosis Risk in Communities (ARIC) study sites. Results appeared in the July 7 Annals of Internal Medicine.
Over an average follow-up of 14.5 years, there were 157 strokes, 50 stroke-related deaths, and 576 all-cause deaths. Compared to patients without lesions, stroke risk more than tripled with lesions smaller than 3 mm only (hazard ratio [HR], 3.47; 95% CI, 1.86 to 6.49), nearly doubled with lesions 3 mm or larger only (HR, 1.94; 95% CI, 1.22 to 3.07), and was more than 8-fold higher with lesions of both sizes (HR, 8.59; 95% CI, 4.69 to 15.73).
Risk was also more than doubled with a white matter hyperintensities score of at least 3 (HR, 2.14; 95% CI, 1.45 to 3.16). (The authors graded periventricular and subcortical white matter hyperintensity on a scale of 0, no white matter signal abnormalities, to 9, extensive confluent white matter involvement. Scores were based on pattern matching to a set of reference standards.) Risk for stroke-related death tripled with lesions smaller than 3 mm only (HR, 3.05; 95% CI, 1.04 to 8.94) and was 7 times higher with lesions of both sizes (HR, 6.97; 95% CI, 2.03 to 23.93).
The authors concluded that clinicians may want to reconsider the practice of dismissing very small cerebral lesions found on MRI. Small lesions may result from vascular pathology or dilated perivascular spaces known as Virchow–Robin spaces, they wrote. But even perivascular spaces are increasingly recognized as potentially pathologic. Lesions of presumed vascular origin and perivascular spaces share similar risk profiles, and perivascular spaces are associated with cerebral small vessel disease severity, stroke and cognitive decline, white matter hyperintensities, and symptomatic lacunar infarctions, all of which support a vascular pathology, they concluded.
The authors wrote, “Regardless of the cause of the lesions, our study shows that even very small lesions are associated with increased risk for stroke and death, adding to a growing corpus of literature supporting associations between very small lesions and cardiovascular risk factors; clinical disease, including atrial fibrillation; and, now, stroke and mortality.”