Blood Pressure Complexity Discriminates Pathological Beat‐to‐Beat Variability as a Marker of Vascular Aging

Abstract

Background Beat‐to‐beat blood pressure variability (BPV) is associated with an increased risk of stroke but can be driven by both healthy physiological processes and failure of compensatory mechanisms. Blood pressure (BP) complexity measures structured, organized variations in BP, as opposed to random fluctuations, and its reduction may therefore identify pathological beat‐to‐beat BPV. Methods and Results In the prospective, population‐based OXVASC (Oxford Vascular Study) Phenotyped Cohort with transient ischemic attack or minor stroke, patients underwent at least 5 minutes of noninvasive beat‐to‐beat monitoring of BP (Finometer) and ECG to derive the following: BPV (coefficient of variation) and complexity (modified multiscale entropy) of systolic BP and diastolic BP, heart rate variability (SD of R‐R intervals), and baroreflex sensitivity (BRS; Welch's method), in low‐ (0.04–0.15 Hz) and high‐frequency (0.15–0.4 Hz) bands. Associations between BPV or BP complexity with autonomic indexes and arterial stiffness were determined (linear regression), unadjusted, and adjusted for age, sex, and cardiovascular risk factors. In 908 consecutive, consenting patients, BP complexity was inversely correlated with BPV coefficient of variation ( P <0.001) and was similarly reduced in patients with hypertension or diabetes ( P <0.001). However, although BPV coefficient of variation had a U‐shaped relationship with age, BP complexity fell systematically across age quintiles (quintile 1: 15.1 [14.0–16.1] versus quintile 5: 13.8 [12.4–15.1]) and was correlated with markers of autonomic dysfunction (heart rate variability SD of R‐R intervals: r = 0.20; BRS low frequency: 0.19; BRS high frequency: 0.26) and arterial stiffness (pulse wave velocity: −0.21; all P <0.001), even after adjustment for clinical variables (heart rate variability SD of R‐R intervals: 0.12; BRS low frequency and BRS high frequency: 0.13 and 0.17; and pulse wave velocity: −0.07; all P <0.05). Conclusions Loss of BP complexity discriminates BPV because of pathological failure of compensatory mechanisms and may represent a less confounded and potentially modifiable risk factor for stroke.

Non-invasive parameters of autonomic function using beat-to-beat cardiovascular variations and arterial stiffness in hypertensive individuals: a systematic review

“…The non-linear measures of BPV, multiscale entropy shows its potential in revealing the blood pressure variations at different time scales or frequencies [ 51 , 97 ]. BP regulation involves various elements, including cardiac output, vascular resistance, and neural and hormonal feedback mechanisms, all operating at different time scales.…”

Blood Pressure Variability and Autonomic Response to an Acute Bout of High Intensity Interval Exercise in Healthy Young Adults

“…Future studies should examine mechanisms such as cardiac output, vasomotor activity, baroreflex sensitivity, and breathing contributions to the changes in BTB BPV during HIIE. (2, 8, 53, 54) Autonomic dysfunction in various other populations such as diabetes and heart failure may also respond to HIIE differently and provide clinical insights about the cardiovascular and autonomic function interaction. (55–57) Our analysis performed low volume HIIE, however future studies could examine effects of short and long interval HIIE which would provide different stimulus to factors that alter the BTB BPV response.…”

Improving the effectiveness of anti-aging modalities by using the constrained disorder principle-based management algorithms

“… 16. Variability in neuro-cardiovascular regulatory mechanisms : Using fractal methods on data extracted from wearable devices to quantify the variability in fluctuating daily physical activity patterns has shown that aging and mortality were associated with decreased variability ( Raichlen et al, 2019 ; Bencivenga et al, 2022 ; Lee et al, 2022 ). Physiological complexity was proposed as a biomarker of aging, and interventions that aim to regain complexity in physical activity might slow the aging process.…”

“…The correlation between aging and the variability or entropy of different cardiovascular parameters, including systolic and diastolic blood pressure, heart rate, and oxygenated hemoglobin, was examined in several studies. Some of these have demonstrated reduced variability with aging or frailty, while others have shown the reverse association ( Fukusaki et al, 2000 ; Viola et al, 2011 ; Nemati et al, 2013 ; Toosizadeh et al, 2022 ; Ogliari et al, 2016 ; Knight et al, 2020 ; Lee et al, 2022 ).…”