INFINITY: Intensive Blood Pressure-Lowering May Preserve Some Cortical Function

A new study in Circulation noted that intensive ambulatory blood pressure-lowering therapy was linked with a reduction in subcortical white matter disease.

“Subcortical microvascular disease represented by brain white matter hyperintensity on MRI is associated with function decline in older people with hypertension,” the authors wrote in their abstract. “The effects of two levels of 24-hour average systolic blood pressure on mobility, white matter disease progression, and cognitive function over three years were studied.”

Researchers for the prospective INFINITY trial averaged at least 75 years of age (mean age in study: 80.5 years, with 54% women) and had systolic hypertension and evidence of white matter hyperintensity lesions as assessed by MRI. The 199 patients were randomized to either a 24-hour mean systolic blood pressure of 130 mm Hg or less (intensive treatment) compared to systolic of 145 mm Hg or less (standard care) with antihypertensive medication. The primary outcomes of interest were changes in mobility (defined as gait speed) and accrual of white matter volume beyond three years.

Mean systolic blood pressure was 127.7 mm Hg in the intensive treatment group after three to four months of treatment and achievement of target blood pressure compared to 144.0 mm Hg in the standard care group (average difference, 16.3 mm Hg). There were no reported changes in gait speed between treatment groups (P=0.91). There were also no reported differences in cognitive outcomes between the cohorts. The changes in white matter hyperintensity volumes were observed to be smaller in the intensive therapy group compared to standard care (0.29% vs. 0.48%, respectively; P=0.03). More adverse events occurred in the standard care cohort than the intensive treatment cohort (17 patients vs. 4 patients, respectively; P=0.01), although falls, with or without injury, were comparable between the study groups.

“Intensive lowering of ambulatory blood pressure reduction in older patients with hypertension did not results in differences in mobility outcomes, but was associated with a reduction in accrual of subcortical white matter disease,” the researchers wrote in their conclusion. “Over periods of more than three years, a reduction in the accumulation of white matter disease may be a factor in conserving function.”