1. In patients with hypertension, intensive blood pressure control to a target of less than 120 mmHg compared to a standard target of less than 140 mm Hg was associated with increased whole-brain cerebral blood flow.
2. Increases in cerebral blood flow associated with intensive blood pressure treatment were more pronounced in patients with a history of cardiovascular disease.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Hypertension is a major risk factor for cardiovascular and cerebrovascular diseases where appropriate blood pressure control has been shown to decrease overall morbidity and mortality. However, the blood pressure target in patients with hypertension has long been debated and it is unknown whether an intensive strategy to control blood pressure leads to potentially harmful cerebral hypoperfusion. This magnetic resonance imaging (MRI) substudy used longitudinal data from the SPRINT trial to assess the association between intensive vs standard systolic blood pressure (SBP) control with whole-brain cerebral blood flow (CBF). The primary endpoint was change from baseline in whole-brain CBF. Secondary endpoints included CBF changes in gray, white, and periventricular white matter. Among 547 patients with hypertension, an intensive SBP target <120mmHg was associated with a significantly larger increase in CBF compared with a standard SBP target of <140mmHg. This association was strongest among patients with a history of cardiovascular disease. A limitation of this study was that MRI data was only collected at 2 time points in the SPRINT trial and does not represent the true longitudinal trajectory and stability of CBF changes in patients with chronic hypertension.
In-Depth [randomized clinical trial]: This comparative efficacy substudy included 547 participants (mean [SD] age, 67.5 [8.1] years; 219 [40.0%] women) from the Systolic Blood Pressure Intervention Trial (SPRINT), where individuals with baseline CBF measures were randomized to an intensive SBP target <120mmHg or standard SBP target <140mmHg. Patients aged ≥50 years with hypertension and increased cardiovascular risk but no diabetes or dementia were included, where 315 participants completed follow-up MRI at a median of 4.0 years after randomization. Overall, mean whole-brain CBF increased from 38.90 to 40.36 (difference, 1.46 [95%CI, 0.08-2.83]) mL/100 g/min in the intensive treatment group while no mean increase was observed in the standard treatment group (37.96 to 37.12; difference, –0.84 [95%CI, –2.30 to 0.61] mL/100 g/min; between-group difference, 2.30 [95%CI, 0.30-4.30; P = .02]). These changes were similarly reflected in CBF measures for gray, white, and periventricular white matter. Furthermore, the association of intensive vs standard treatment with CBF was similar across subgroups including age, sex, race, chronic kidney disease, SBP, orthostatic hypotension, and frailty. However, among patients with a history of cardiovascular disease, a greater mean increase in CBF was associated with intensive treatment (interaction P = .05).
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