Cognitive Risks Tied to High BP Brain Changes

Changes in periventricular white matter hyperintensities (WMH) accompanied development of mild cognitive impairment in adults with hypertension, a longitudinal population-based study in Spain found.

Hypertensive older adults who showed a marked progression of periventricular WMH had a sixfold risk of incident mild cognitive impairment compared with patients without this progression (OR 6.184, 95% CI 1.506-25.370, P=0.011), according to Pilar Delgado Martinez, MD, PhD, of the Institut de Recerca Hospital Vall d’Hebron in Barcelona, and colleagues.

These patients also demonstrated a significant decrease in global cognition (adjusted mean -0.519 ± 0.176 vs 0.057 ± 0.044, P=0.004), the team reported in Hypertension.

Finding new ways to detect cognitive impairment may help identify who is at risk for dementia, the authors noted. “As patients with hypertension are at high risk for cerebral small vessel disease progression, the identification of specific lesions that have higher odds of impairing cognition may have useful implications in clinical practice.”

The study builds upon prior research about cerebral small vessel disease and cognitive function, noted Ilya Nasrallah, MD, PhD, of the University of Pennsylvania in Philadelphia, who was not involved with the study.

“Understanding the link between small vessel disease and cognition is important because we are currently able to alter the course of small vessel disease,” Nasrallah told MedPage Today. “In the SPRINT study, for example, we showed that intensive treatment of hypertension to <120 mm Hg systolic resulted in lower incident mild cognitive impairment and lower progression of cerebral white matter lesions."

In the Barcelona study, the researchers followed 345 hypertensive men and women in the ISSYS (Investigating Silent Strokes in Hypertensives: A Magnetic Resonance Imaging Study) cohort, an ongoing epidemiological, observational study. At baseline (from 2010 to 2012), participants were a median age of 65 and had no previous dementia or stroke. Most — 94.2% — were being treated for hypertension and 55.4% were male.

Mean follow-up was 3.95 years and average blood pressure at follow-up was 144.5/76.5 mm Hg.

At baseline and follow-up, patients underwent evaluations that included brain MRI and cognitive testing. The researchers used the Dementia Rating Scale 2nd version (DRS-2) to assess a general measure of cognitive function, and asked participants whose DRS-2 scores suggested cognitive impairment to undergo a second evaluation to establish a cognitive diagnosis. They qualitatively defined MRI changes in periventricular white matter hyperintensities and deep white matter hyperintensities as “none,” “minor,” or “marked.”

During the study, 9.1% of participants developed mild cognitive impairment. Incident lacunar infarcts occurred in 6.1% of participants and cerebral microbleeds in 5.5%. Minor or marked periventricular WMH progression appeared in 22% of patients and deep WMH progression occurred in 48%.

Only marked progression of periventricular WMH was associated with incident mild cognitive decline; changes in deep WMH, incident infarcts, and cerebral microbleeds were not tied to incident cognitive impairment. Incident cerebral microbleeds, however, were tied to a decline in attention.

“This study confirms previous observations on the effects of hypertension on brain vasculature and cognitive function in elderly individuals,” observed Oscar Lopez, MD, of the University of Pittsburgh, who was not involved with the research. “It emphasizes the importance of a strict adherence to antihypertensive treatments,” he told MedPage Today.

The researchers noted several limitations to their study. Due to budget constraints, patients were selected for follow-up based on the severity of baseline cerebral small vessel disease, so results may not apply to all patients with hypertension. Volumetric approaches to measuring MRI changes in hyperintensities would have been more precise than qualitative assessments. The team also did not include neurodegeneration markers like tau or amyloid-beta which may be related to hypertension and cerebral small vessel disease lesions.