Relationship Between Arterial Stiffness Index, Pulse Pressure, and Magnetic Resonance Imaging Markers of White Matter Integrity: A UK Biobank Study

Associations of cardiac function and arterial stiffness with cerebrovascular disease

BACKGROUND

White matter hyperintensities (WMHs) represent diffuse small vessel disease implicating the cardiac, systemic, and cerebral vasculatures. As the brain may be the end-organ of cumulative vascular disease, and higher education is protective of both cardiovascular and brain health, we aim to clarify their intertwining relationships.

METHODS

We evaluated participants (mean age = 64) from the UK Biobank with neuroimaging measures of WMHs, left ventricular ejection fraction (LVEF) quantified using cardiovascular MRI, and arterial stiffness index (ASI) quantified using finger photoplethysmography. We used multiple regression to evaluate the basic, independent, and interactive relationships of LVEF status (n = 27,512) and ASI (n = 33,584) with WMHs. Moderated mediation analysis was used to determine whether the relationship between LVEF status and WMH was mediated by ASI and moderated by education.

RESULTS

Abnormal LVEF (β = -0.082, p < 0.001) and higher ASI (β = 0.02, p < 0.001) were associated with greater WMHs separately and independently, but not interactively. Moderated mediation analyses revealed that the relationship between abnormal LVEF and WMH was mediated by ASI, for individuals with lower education (β = -0.004, p < 0.001). Abnormal LVEF was associated with lower cortical thickness in 16 predominantly frontotemporal and select parietal regions (FDR, q < 0.05).

CONCLUSIONS

Cardiovascular dysfunction is associated with regional cerebral atrophy and may precipitate cerebrovascular disease via stiffening of systemic vasculatures, particularly for individuals with lower education. Integrative approaches to study biophysiological vascular systems can elucidate the complex interplay between biological and social determinants of brain and cerebrovascular health.

White matter microstructural integrity is associated with retinal vascular caliber in adolescents with bipolar disorder

OBJECTIVE

Reduced white matter integrity is observed in bipolar disorder (BD), and is associated with cardiovascular risk in adults. This topic is underexplored in youth, and in BD, where novel microvascular measures may help to inform understanding of the vascular-brain connection. We therefore examined the association of retinal vascular caliber with white matter integrity in a cross-sectional sample of adolescents with and without BD.

METHODS

Eighty-four adolescents (n = 42 BD, n = 42 controls) completed retinal imaging, yielding arteriolar and venular caliber. Diffusion tensor imaging measured white matter fractional anisotropy (FA). Multiple linear regression tested associations between retinal vascular caliber and FA in regions-of-interest; corpus callosum, anterior thalamic radiation, uncinate fasciculus, and superior longitudinal fasciculus. Complementary voxel-wise analyses were performed.

RESULTS

Arteriolar caliber was elevated in adolescents with BD relative to controls (F(1,79) = 6.15, p = 0.02, η2p = 0.07). In the overall sample, higher venular caliber was significantly associated with lower corpus callosum FA (β = -0.24, puncorrected = 0.04). In voxel-wise analyses, higher arteriolar caliber was significantly associated with lower corpus callosum and forceps minor FA in the overall sample (β = -0.46, p = 0.03). A significant diagnosis-by-venular caliber interaction on FA was noted in 5 clusters including the right retrolenticular internal capsule (β = 0.72, p = 0.03), corticospinal tract (β = 0.72, p = 0.04), and anterior corona radiata (β = 0.63, p = 0.04). In each instance, venular caliber was more positively associated with FA in BD vs. controls.

CONCLUSION

Retinal microvascular measures are associated with white matter integrity in BD, particularly in the corpus callosum. This study was proof-of-concept, designed to guide future studies focused on the vascular-brain interface in BD.

Added value of arterial stiffness index for the 10-year atherosclerotic cardiovascular disease risk determination in a middle-aged population-based study

OBJECTIVE

Atherosclerotic cardiovascular disease (ASCVD) is considered the leading cause of mortality worldwide. Arterial stiffness, measured by arterial stiffness index (ASI), could be a main predictor in target damage of organs. Uncertainty remains regarding the contribution of ASI to estimated ASCVD risk. This study investigates the added value of ASI in ASCVD risk determination using the general UK Biobank middle-aged population.

METHODS

Among 100,598 participants from the UK Biobank population, ASI was assessed and associations between ASCVD risk were stratified by sex and estimated using multiple linear and logistic regressions adjusted for heart rate, physical activity, alcohol status, smocking pack years, BMI categories and CKD.

RESULTS

Males presented higher ASCVD risk than females (8.58% vs. 2.82%, p < 0.001) and higher ASI levels (9.50 m/s vs. 7.00 m/s, p < 0.001). The Youden index was determined at 9.70 m/s in males (p < 0.001) and 10.46 m/s in females (p < 0.001). Among females, participants with ASI > 10.46 m/s showed higher ASCVD risk than others (3.64% vs. 2.56%, p < 0.001), similar results were observed for males (9.92% vs. 7.21%, p < 0.001). In males, ASI showed significant added value information when including overall covariates (AUC = 0.695 vs. AUC = 0.663, p < 0.001). Similar results were observed in females (AUC = 0.693 vs. AUC = 0.687, p = 0.001). In both genders, for the association between ASI and ASCVD risk, nonlinear relationships were observed with higher accuracies than linear models.

CONCLUSION

Further studies should investigate ASCVD risk stratification management depending on ASI measurement.

Association between tobacco smoking and alcohol consumption with arterial stiffness

Few investigations have been performed between tobacco smoking, alcohol, and arterial stiffness. The purpose of our study was to investigate the association between smoking use and alcohol with arterial stiffness index (ASI) in a middle-age population. Smoking pack-years and cigarettes per day were defined as alcohol consumption in units/day. Sex associations between smoking and alcohol with ASI were estimated using multiple linear regressions. Interactions and synergistic effects were investigating. 98 039 individuals of the UK Biobank cohort were included (45 457 men and 52 582 women). ASI levels were higher in men than in women (9.91 vs. 8.71 m/s, p < .001), and showed higher relationship to smoking tobacco in multiple linear regression models in women than in men (FDR logworth 78.4 vs. 52.7). The findings revealed that ASI was higher among current smokers than never smokers in both sex and after adjustment for all covariates (in men 10.4 vs. 9.6 and in women 9.5 vs. 8.5 m/s, p < .001). Alcohol consumption per day was positively associated with higher levels of ASI in both sex, but with a less relationship (FDR logworth for men = 2.8, for women = 2.5). An interaction was observed between smoking information and alcohol in men but not in women. Synergistic effects were observed by adding smoking information on alcohol consumption models in men and women (p = .029, p < .001, respectively). Smoking and alcohol were associated with higher ASI in both sex but with a higher relationship among women. The findings suggest the importance of considering smoking and alcohol consumption cessation in cardiovascular diseases prevention.

Arterial stiffness and biological parameters: A decision tree machine learning application in hypertensive participants

Arterial stiffness, measured by arterial stiffness index (ASI), could be considered a main denominator in target organ damage among hypertensive subjects. Currently, no reported ASI normal references have been reported. The index of arterial stiffness is evaluated by calculation of a stiffness index. Predicted ASI can be estimated regardless to age, sex, mean blood pressure, and heart rate, to compose an individual stiffness index [(measured ASI-predicted ASI)/predicted ASI]. A stiffness index greater than zero defines arterial stiffness. Thus, the purpose of this study was 1) to determine determinants of stiffness index 2) to perform threshold values to discriminate stiffness index and then 3) to determine hierarchical associations of the determinants by performing a decision tree model among hypertensive participants without CV diseases. A study was conducted from 53,363 healthy participants in the UK Biobank survey to determine predicted ASI. Stiffness index was applied on 49,452 hypertensives without CV diseases to discriminate determinants of positive stiffness index (N = 22,453) from negative index (N = 26,999). The input variables for the models were clinical and biological parameters. The independent classifiers were ranked from the most sensitives: HDL cholesterol≤1.425 mmol/L, smoking pack years≥9.2pack-years, Phosphate≥1.172 mmol/L, to the most specifics: Cystatin c≤0.901 mg/L, Triglycerides≥1.487 mmol/L, Urate≥291.9 μmol/L, ALT≥22.13 U/L, AST≤32.5 U/L, Albumin≤45.92 g/L, Testosterone≥5.181 nmol/L. A decision tree model was performed to determine rules to highlight the different hierarchization and interactions between these classifiers with a higher performance than multiple logistic regression (p<0.001). The stiffness index could be an integrator of CV risk factors and participate in future CV risk management evaluations for preventive strategies. Decision trees can provide accurate and useful classification for clinicians.

Association between cannabis use and blood pressure levels according to comorbidities and socioeconomic status

The associations between blood pressure and cannabis use remain inconsistent. The purpose of our study was to examine gender stratified associations of cannabis use and blood pressure [systolic, diastolic blood pressure (BP), pulse pressure (PP)] levels among the general UK Biobank population based study. Among 91,161 volunteers of the UK Biobank population, cannabis use status was assessed by questionnaire and range as heavy, moderate, low and never users. Associations between cannabis use and BP were estimated using multiple gender linear regressions. In adjusted covariates models, lifetime heavy cannabis use was associated with decrease in both SBP, DBP and PP in both genders, but with a higher effect among women (for SBP in men, b = - 1.09 (0.27), p < 0.001; in women, b = - 1.85 (0.36), p < 0.001; for DBP in men, b = - 0.50 (0.15), p < 0.001; in women, b = - 0.87 (0.17), p < 0.001; and for PP in men, b = - 0.60 (0.20), p < 0.001; in women, b = - 0.97 (0.27), p < 0.001. Among men, lower SBP and DBP levels were observed with participants without dyslipidemia and lower PP in participants with high income levels. Among women, lower SBP, DBP and PP were observed with current smokers, moderate/low alcohol levels and participants without dyslipidemia. Current cannabis use was associated with lower SBP levels in men (b = - 0.63 (0.25), p = 0.012) and in women (b = - 1.17 (0.31), p < 0.001). Same results were observed for DBP and PP. Negative association between BP in men was found but not in women. The small association in BP differences between heavy users and never users remains too small to adopt cannabis-blood pressure public policy in clinical practice.

Arterial stiffness and progression of white matter hyperintensities of presumed vascular origin in community-dwelling older adults of Amerindian ancestry: The Atahualpa Project Cohort

OBJECTIVE

Arterial stiffness - as measured by the aortic pulse wave velocity (aPWV) - has been associated with biomarkers of cerebral small vessel disease (cSVD), in particular with white matter hyperintensities (WMH) of presumed vascular origin. Most studies have been conducted in White and Asian populations, and information on this relationship in other ethnic groups is limited. We designed a longitudinal prospective study to assess the impact of aPWV on WMH progression in individuals of Amerindian ancestry.

PATIENTS AND METHODS

Participants of the Atahualpa Project Cohort were assessed at baseline with aPWV determinations, clinical interviews and brain MRIs. At the end of the study, brain MRIs were repeated in order to ascertain WMH progression. Poisson regression models adjusted for demographics and cardiovascular risk factors were fitted to assess WMH progression incidence rate by baseline levels of aPWV.

RESULTS

The study included 260 individuals aged ≥60 years (mean age: 65.6 ± 6.1 years; 57 % women). The mean aPWV was 9.9 ± 1.5 m/s. Follow-up MRIs revealed WMH progression in 102 (39 %) individuals after a mean follow-up of 6.5 ± 1.4 years. Unadjusted analysis showed a higher baseline aPWV among subjects that developed WMH progression compared with those who did not (p < 0.001). Multivariate Poisson regression models showed an increased WMH progression rate among individuals in the second (IRR: 2.06; 95 % C.I.: 1.09-3.88) and third (IRR: 2.75; 95 % C.I.: 1.29-5.87) tertiles of aPWV compared with those in the first tertile.

CONCLUSIONS

aPWV is associated with WMH progression, suggesting a link between atherosclerosis and cSVD in the study population.