Aortic Stiffness, Pulse Pressure, and Cerebral Pulsatility Progress Despite Best Medical Management: The OXVASC Cohort

Factors associated with progression of arterial stiffness in ischemic stroke survivors: the Norwegian Stroke in the Young Study

BACKGROUND

Progressive arterial stiffening may increase the risk of recurrent cardiovascular events in ischemic stroke survivors. Information about factors associated with progressive arterial stiffening during the follow-up of young patients with ischemic stroke is lacking.

METHODS

Arterial stiffness by carotid-femoral pulse wave velocity (cf-PWV) and ambulatory 24-hour blood pressure (24hBP) were assessed in 81 women and 190 men ≤60 years of age included in the Norwegian Stroke in the Young (NOR-SYS) study 3 months and 5.5 years after the incident ischemic stroke, representing baseline and follow-up. Covariables of change in cf-PWV were identified using linear regression analysis.

RESULTS

At baseline, women had less prevalent hypertension (53% vs. 69%, p < 0.05), and lower clinic and 24hBP than men, whereas age, obesity, and prevalence of smoking and antihypertensive drug treatment did not differ. During follow-up, systolic 24hBP remained unchanged, while diastolic 24hBP fell significantly (p < 0.01). Cf-PWV was lower in women both at baseline (7.3 m/s vs. 8.1 m/s) and at follow-up (7.3 m/s vs. 8.0 m/s, both p < 0.001), but the average change during follow-up did not differ between genders. In linear regression analysis, an increase in cf-PWV at the 5-year follow-up was associated with the presence of hypertension and lower cf-PWV at baseline, and higher systolic 24hBP and lack of use of antihypertensive treatment at follow-up (all p < 0.05).

CONCLUSION

In ischemic stroke survivors participating in the NOR-SYS study, the 5-year increase in cf-PWV did not differ between genders and was associated with higher systolic 24hBP and lack of antihypertensive treatment.

How Would I Treat My Own Thoracoabdominal Aortic Aneurysm: Perioperative Considerations From the Anesthesiologist Perspective

A thoracoabdominal aortic aneurysm (TAAA) can be potentially life-threatening due to its associated risk of rupture. Thoracoabdominal aortic aneurysm repair, performed as endovascular repair and/or open surgery, is the recommended therapy of choice. Hemodynamic instability, severe blood loss, and spinal cord or cerebral ischemia are some potential hazards the perioperative team has to face during these procedures. Therefore, preoperative risk assessment and intraoperative anesthesia management addressing these potential hazards are essential to improving patients' outcomes. Based on a presented index case, an overview focusing on anesthetic measures to identify perioperatively and manage these risks in TAAA repair is provided.

Circadian and Diurnal Regulation of Cerebral Blood Flow

Circadian and diurnal variation in cerebral blood flow directly contributes to the diurnal variation in the risk of stroke, either through factors that trigger stroke or due to impaired compensatory mechanisms. Cerebral blood flow results from the integration of systemic hemodynamics, including heart rate, cardiac output, and blood pressure, with cerebrovascular regulatory mechanisms, including cerebrovascular reactivity, autoregulation, and neurovascular coupling. We review the evidence for the circadian and diurnal variation in each of these mechanisms and their integration, from the detailed evidence for mechanisms underlying the nocturnal nadir and morning surge in blood pressure to identifying limited available evidence for circadian and diurnal variation in cerebrovascular compensatory mechanisms. We, thus, identify key systemic hemodynamic factors related to the diurnal variation in the risk of stroke but particularly identify the need for further research focused on cerebrovascular regulatory mechanisms.

Blood pressure fragmentation as a new measure of blood pressure variability: association with predictors of cardiac surgery outcomes

Background: Fluctuations in beat-to-beat blood pressure variability (BPV) encode untapped information of clinical utility. A need exists for developing new methods to quantify the dynamical properties of these fluctuations beyond their mean and variance. Objectives: Introduction of a new beat-to-beat BPV measure, termed blood pressure fragmentation (BPF), and testing of whether increased preoperative BPF is associated with (i) older age; (ii) higher cardiac surgical risk, assessed using the Society of Thoracic Surgeons' (STS) Risk of Morbidity and Mortality index and the European System for Cardiac Operative Risk Evaluation Score (EuroSCORE II); and (iii) longer ICU length of stay (LOS) following cardiac surgery. The secondary objective was to use standard BPV measures, specifically, mean, SD, coefficient of variation (CV), average real variability (ARV), as well a short-term scaling index, the detrended fluctuation analysis (DFA) ⍺1 exponent, in the same type of analyses to compare the results with those obtained using BPF. Methods: Consecutive sample of 497 adult patients (72% male; age, median [inter-quartile range]: 67 [59-75] years) undergoing cardiac surgery with cardiopulmonary bypass. Fragmentation, standard BPV and DFA ⍺1 measures were derived from preoperative systolic blood pressure (SBP) time series obtained from radial artery recordings. Results: Increased preoperative systolic BPF was associated with older age, higher STS Risk of Morbidity and Mortality and EuroSCORE II values, and longer ICU LOS in all models. Specifically, a one-SD increase in systolic BPF (9%) was associated with a 26% (13%-40%) higher likelihood of longer ICU LOS (>2 days). Among the other measures, only ARV and DFA ⍺1 tended to be associated with longer ICU LOS. However, the associations did not reach significance in the most adjusted models. Conclusion: Preoperative BPF was significantly associated with preoperative predictors of cardiac surgical outcomes as well as with ICU LOS. Our findings encourage future studies of preoperative BPF for assessment of health status and risk stratification of surgical and non-surgical patients.

Stiffness and Elasticity of Aorta Assessed Using Computed Tomography Angiography as a Marker of Cardiovascular Health-A Cross-Sectional Study

Cardiovascular (CV) health can be measured using the American Health Association's Life's Simple 7 scale (ALS7). Aortic stiffness (AoS) and elasticity (AoE) can be assessed using various methods, e.g., computed tomography (CT). To measure AoE, we use aortic strain and distensibility (AoD). The aim of this study was to examine the relationship between ALS7, AoS, and AoE. The study group (SG) was composed of 96 patients (mean age 70.41 ± 8.32 years) with a BMI of 25.58 ± 3.12 kg/m2; 28.1% were smokers, 54.2% had hypertension, 11.4% had diabetes, and 67.7% had hypercholesterolemia. The SG was further divided into three subgroups (optimal (ALS7-H), intermediate (ALS7-I), and inadequate (ALS7-L)) based on the ALS7. The AoS and AoE were assessed in each of them. We found that the ALS7-I and ALS7-H had significantly lower AoS values compared to the ALS7-L (AoS: 3.50 ± 0.53 and 4.10 ± 0.70 vs. 4.57 ± 1.03, respectively). The opposite relationship was observed for AoE measured with AoD in the ALS7-H vs. ALS7-L (AoD: 0.23 ± 0.14 vs. 0.11 ± 0.09 cm2/dyn). AoS correlated (r = 0.61) with systolic blood pressure (BP). In our regression model, higher scores on the ALS7 in BP, smoking, and BMI were independent protective factors against greater AoS. Higher ALS7 scores in BP, smoking, BMI, and physical activity were protective factors against lesser aortic strain. Higher scores in ALS7 for BP and smoking were protective factors against lesser AoD. We conclude that better cardiovascular health expressed via higher scores obtained on the ALS7 is associated with lower AoS and higher AoE on CT.

Associations of Cerebrovascular Regulation and Arterial Stiffness With Cerebral Small Vessel Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Cerebral small vessel disease (cSVD) is a major contributing factor to ischemic stroke and dementia. However, the vascular pathologies of cSVD remain inconclusive. The aim of this systematic review and meta-analysis was to characterize the associations between cSVD and cerebrovascular reactivity (CVR), cerebral autoregulation, and arterial stiffness (AS).

METHODS AND RESULTS

MEDLINE, Web of Science, and Embase were searched from inception to September 2023 for studies reporting CVR, cerebral autoregulation, or AS in relation to radiological markers of cSVD. Data were extracted in predefined tables, reviewed, and meta-analyses performed using inverse-variance random effects models to determine pooled odds ratios (ORs). A total of 1611 studies were identified; 142 were included in the systematic review, of which 60 had data available for meta-analyses. Systematic review revealed that CVR, cerebral autoregulation, and AS were consistently associated with cSVD (80.4%, 78.6%, and 85.4% of studies, respectively). Meta-analysis in 7 studies (536 participants, 32.9% women) revealed a borderline association between impaired CVR and cSVD (OR, 2.26 [95% CI, 0.99-5.14]; P=0.05). In 37 studies (27 952 participants, 53.0% women) increased AS, per SD, was associated with cSVD (OR, 1.24 [95% CI, 1.15-1.33]; P<0.01). Meta-regression adjusted for comorbidities accounted for one-third of the AS model variance (R2=29.4%, Pmoderators=0.02). Subgroup analysis of AS studies demonstrated an association with white matter hyperintensities (OR, 1.42 [95% CI, 1.18-1.70]; P<0.01).

CONCLUSIONS

The collective findings of the present systematic review and meta-analyses suggest an association between cSVD and impaired CVR and elevated AS. However, longitudinal investigations into vascular stiffness and regulatory function as possible risk factors for cSVD remain warranted.

Arterial Stiffness Is Associated With Small Vessel Disease Irrespective of Blood Pressure in Stroke-Free Individuals

BACKGROUND

Arterial stiffness and hypertension are important risk factors for cerebral small vessel disease (CSVD). Clinically, there are hypertensive patients with low pulse wave velocity (PWV) and nonhypertensive individuals with high PWV. We aimed to determine the effects of arterial stiffness on CSVD in normotensive individuals.

METHODS

An observational cross-sectional study was conducted in 1894 stroke-free participants who underwent brain magnetic resonance imaging and brachial-ankle pulse wave velocity (baPWV) measurements at a health checkup between 2013 and 2020. CSVD was defined as any of following: white matter hyperintensities, cerebral microbleeds, silent lacunar infarcts, and enlarged perivascular spaces. baPWV was measured using an automatic oscillometric device. Participants were divided into 4 groups according to the following cutoff points: low blood pressure (BP, <120/80 mm Hg) with low baPWV (<14.63 m/s, a cutoff value that predicted CSVD); high BP (≥120/80 mm Hg) with low baPWV; low BP with high baPWV (≥14.63 m/s); and high BP with high baPWV.

RESULTS

The mean age of the participants was 57±13 years (41% women). The prevalence of CSVD was 718 (38%), which was higher in the low BP with high baPWV (56%) and high BP with high baPWV (55%) groups than in the high BP with low baPWV (24%) and low BP with low baPWV (22%) groups. Compared with the low BP with low baPWV group, the low BP with high baPWV group (odds ratio, 1.63 [95% CI, 1.09-2.43]) and the high BP with high baPWV group (odds ratio, 1.86 [95% CI, 1.39-2.49]) had a significantly higher multivariable-adjusted risk for CSVD.

CONCLUSIONS

Individuals with a high baPWV had a higher prevalence of CSVD, independent of BP status. Higher arterial stiffness is likely to be a more important risk factor for CSVD than BP status in stroke-free individuals.

Low Heart Rate Is Associated with Cerebral Pulsatility after TIA or Minor Stroke

OBJECTIVE

Beta-blockers are beneficial in coronary artery disease but less so in stroke prevention and dementia, potentially due to reduced heart rate (HR). Cerebral pulsatility is strongly associated with cerebral small vessel disease (SVD) and may be increased by lower diastolic pressures resulting from longer cardiac cycles.

METHODS

Patients 4-6 weeks after TIA or non-disabling stroke (Oxford Vascular Study) underwent 5 minutes continuous monitoring of blood pressure (BP), electrocardiogram (ECG), and middle cerebral artery flow velocity (transcranial ultrasound). Beat-to-beat relationships between HR, blood pressure and Gosling's pulsatility index (MCA-PI) are reported as beta-coefficients from general linear models for each individual.

RESULTS

Across 759 patients, average MCA-PI during monitoring was associated with lower HR and diastolic BP (DBP) and greater systolic BP (SBP) (∆MCA-PI per 10 bpm/mmHg: -0.02, -0.04, 0.03, all p < 0.001), with HR particularly associated with low end-diastolic cerebral velocity (0.86, p = 0.014). Beat-to-beat HR was strongly associated with concurrent low DBP and high SBP, potentially mediating the association with greater beat-to-beat cerebral pulsatility (average ∆MCA-PI vs HR/DBP/SBP unadjusted: -0.062, -0.052, 0.0092; adjusted for concurrent BP: -0.039, -0.11, 0.041). The beat-to-beat association between HR and MCA-PI increased with age, beta-blockers, arterial stiffness, low HR (age > 70 + HR < 65 vs age < 70 + HR > 65: -0.081 vs -0.024, interaction p < 0.001), and severe SVD on MRI (age > 70 + severe vs age < 70 + none: -0.087 vs -0.047, interaction p = 0.03), with interactions between age, severe SVD, and low HR synergistically increasing MCA-PI.

INTERPRETATION

Low HR is associated with greater cerebral pulsatility in patients with SVD, potentially mediated by lower diastolic blood flow and representing a novel potential treatment target. ANN NEUROL 2022;92:909-920.