Wright, Clinton B.

In the SPRINT (Systolic Blood Pressure Intervention Trial), the number of strokes did not differ significantly by treatment group. However, stroke subtypes have heterogeneous causes that could respond differently to intensive blood pressure control. SPRINT participants (N=9361) were randomized to target systolic blood pressures of <120 mm Hg (intensive treatment) compared with <140 mm Hg (standard treatment). We compared incident hemorrhage, cardiac embolism, large- and small-vessel infarctions across treatment arms. Participants randomized to the intensive arm had mean systolic blood pressures of 121.4 mm Hg in the intensive arm (N=4678) and 136.2 mm Hg in the standard arm (N=4683) at one year. Sixty-nine strokes occurred in the intensive arm and 78 in the standard arm when SPRINT was stopped. The breakdown of stroke subtypes across treatment arms included hemorrhagic (intensive treatment, n=6, standard treatment, n=7) and ischemic stroke subtypes (large artery atherosclerosis: intensive treatment n=11, standard treatment, n=13; cardiac embolism: intensive treatment n=11, standard treatment n=15; small artery occlusion: intensive treatment n=8, standard treatment n=8; other ischemic stroke: intensive treatment n=3, standard treatment n=1). Fewer strokes occurred among participants without prior cardiovascular disease in the intensive (n=43) than the standard arm (n=61), but the difference did not reach predefined statistical significance level of 0.05 ( P =0.09). The interaction between baseline cardiovascular risk factor status and treatment arm on stroke risk did not reach significance ( P =0.05). Similar numbers of stroke subtypes occurred in the intensive BP control and standard control arms of SPRINT.

AbstractBackgroundHypertension is a major risk factor for cardiovascular and cerebrovascular disease including stroke, small vessel disease, and dementia. The Systolic blood PRessure INTervention (SPRINT) randomized trial prospectively evaluated the effects of intensive systolic blood pressure (SBP) control (target SBP<120mmHg) versus standard control (SBP<140mmHg) on cardiovascular outcomes in individuals without baseline diabetes or stroke, and included cerebral blood flow (CBF) measurements. Previous studies with much smaller sample sizes and shorter duration suggested stable CBF in response to intensive treatment (SBP<125mmHg) [1], but long term effects are unknown. We evaluated the long‐term effects of intensive blood pressure treatment on CBF.MethodWhole brain CBF was measured at 3T using pseudocontinuous arterial spin labeled (ASL) perfusion MRI at baseline and after 3.9±0.3 years. Total white matter lesion (WML) load was measured from Fluid Attenuated Inversion Recovery T2 MRI. Data from 324 subjects with adequate ASL scan quality acquired from 6 sites were included.ResultDemographics and scanner specific CBF values are provided in Table 1. The intensive treatment group was older (p=0.01), but was otherwise similar to the standard group at baseline. There was a significant effect on the longitudinal CBF change (p=0.006) of the intensive treatment (5.7% increase) compared to the standard treatment (4.0% decrease, Fig 1). Secondary analysis showed a significant increase in age‐adjusted fractional CBF for the intensive treatment group (p<0.001) with no change (p=0.24) in the standard treatment group. Change in CBF was not associated with change in WML.ConclusionSustained intensive antihypertensive treatment does not reduce whole brain CBF, in fact it showed an increase in whole brain CBF relative to standard therapy. While improved CBF might contribute to the reduced WML progression observed in the intensive‐therapy group versus standard therapy in SPRINT[2], we did not observe a direct correlation between CBF changes and WML changes. References: (1) Croall et al. JAMA‐Neurol,2018; (2) Nasrallah et al., JAMA‐Neurol, 2019.

Background and Purpose: Periventricular white matter hyperintensities (WMH; PVWMH) and deep WMH (DWMH) are regional classifications of WMH and reflect proposed differences in cause. In the first study, to date, we undertook genome-wide association analyses of DWMH and PVWMH to show that these phenotypes have different genetic underpinnings. Methods: Participants were aged 45 years and older, free of stroke and dementia. We conducted genome-wide association analyses of PVWMH and DWMH in 26,654 participants from CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology), ENIGMA (Enhancing Neuro-Imaging Genetics Through Meta-Analysis), and the UKB (UK Biobank). Regional correlations were investigated using the genome-wide association analyses -pairwise method. Cross-trait genetic correlations between PVWMH, DWMH, stroke, and dementia were estimated using LDSC. Results: In the discovery and replication analysis, for PVWMH only, we found associations on chromosomes 2 ( NBEAL ), 10q23.1 ( TSPAN14/FAM231A ), and 10q24.33 ( SH3PXD2A). In the much larger combined meta-analysis of all cohorts, we identified ten significant regions for PVWMH: chromosomes 2 (3 regions), 6, 7, 10 (2 regions), 13, 16, and 17q23.1. New loci of interest include 7q36.1 ( NOS3 ) and 16q24.2. In both the discovery/replication and combined analysis, we found genome-wide significant associations for the 17q25.1 locus for both DWMH and PVWMH. Using gene-based association analysis, 19 genes across all regions were identified for PVWMH only, including the new genes: CALCRL (2q32.1), KLHL24 (3q27.1), VCAN (5q27.1), and POLR2F (22q13.1). Thirteen genes in the 17q25.1 locus were significant for both phenotypes. More extensive genetic correlations were observed for PVWMH with small vessel ischemic stroke. There were no associations with dementia for either phenotype. Conclusions: Our study confirms these phenotypes have distinct and also shared genetic architectures. Genetic analyses indicated PVWMH was more associated with ischemic stroke whilst DWMH loci were implicated in vascular, astrocyte, and neuronal function. Our study confirms these phenotypes are distinct neuroimaging classifications and identifies new candidate genes associated with PVWMH only.

Importance Black individuals are more likely than white individuals to develop dementia. Whether higher blood pressure (BP) levels in black individuals explain differences between black and white individuals in dementia risk is uncertain. Objective To determine whether cumulative BP levels explain racial differences in cognitive decline. Design, Setting, and Participants Individual participant data from 5 cohorts (January 1971 to December 2017) were pooled from the Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Cardiovascular Health Study, Framingham Offspring Study, and Northern Manhattan Study. Outcomes were standardized as t scores (mean [SD], 50 [10]); a 1-point difference represented a 0.1-SD difference in cognition. The median (interquartile range) follow-up was 12.4 (5.9-21.0) years. Analysis began September 2018. Main Outcomes and Measures The primary outcome was change in global cognition, and secondary outcomes were change in memory and executive function. Exposures Race (black vs white). Results Among 34 349 participants, 19 378 individuals who were free of stroke and dementia and had longitudinal BP, cognitive, and covariate data were included in the analysis. The mean (SD) age at first cognitive assessment was 59.8 (10.4) years and ranged from 5 to 95 years. Of 19 378 individuals, 10 724 (55.3%) were female and 15 526 (80.1%) were white. Compared with white individuals, black individuals had significantly faster declines in global cognition (−0.03 points per year faster [95% CI, −0.05 to −0.01]; P = .004) and memory (−0.08 points per year faster [95% CI, −0.11 to −0.06]; P &amp;lt; .001) but significantly slower declines in executive function (0.09 points per year slower [95% CI, 0.08-0.10]; P &amp;lt; .001). Time-dependent cumulative mean systolic BP level was associated with significantly faster declines in global cognition (−0.018 points per year faster per each 10–mm Hg increase [95% CI, −0.023 to −0.014]; P &amp;lt; .001), memory (−0.028 points per year faster per each 10–mm Hg increase [95% CI, −0.035 to −0.021]; P &amp;lt; .001), and executive function (−0.01 points per year faster per each 10–mm Hg increase [95% CI, −0.014 to −0.007]; P &amp;lt; .001). After adjusting for cumulative mean systolic BP, differences between black and white individuals in cognitive slopes were attenuated for global cognition (−0.01 points per year [95% CI, −0.03 to 0.01]; P = .56) and memory (−0.06 points per year [95% CI, −0.08 to −0.03]; P &amp;lt; .001) but not executive function (0.10 points per year [95% CI, 0.09-0.11]; P &amp;lt; .001). Conclusions and Relevance These results suggest that black individuals’ higher cumulative BP levels may contribute to racial differences in later-life cognitive decline.

There is limited information on participants’ adherence and reasons for declining consent in observational cohort studies conducted in remote rural communities. We aimed at sharing lessons learned during the Atahualpa Project, a population-based cohort study conducted in a rural Ecuadorian village. Atahualpa residents aged ≥40 years identified during door-to-door surveys who signed a consent form were enrolled. Annual surveys were conducted to assess the number of participants who moved out of the village, as well as those who died, declined consent, and newly entered the study. Reasons for declining consent were tabulated. Abstracted data included age, sex, education, disability, time between enrollment and declining consent, and reasons for withdrawal. We also counted participants who, despite expressing their willingness to continue in the study, refused specific procedures. After five years of follow-up, 54 (6.3%) of 863 enrolled individuals declined consent. Increasing age and disability had no impact on declining consent. In contrast, refusal was higher among relatives or neighbors of a given participant declining consent. Most people who declined consent did so after one or two years of enrollment. Less than 20% of enrolled individuals refused certain procedures. “Fear of the needle” was the most frequent reason for refusing blood tests, and common reasons for declining complimentary exams were lack of interest and time constraints. Cohort retention in the Atahualpa Project is high. Main reasons for this adherence include adequate selection of the village, detailed planning of procedures, assurance of sponsorship, and field personnel who continuously engage with study participants. This trial is registered with NCT01627600.