Increased multimorbidity is associated with impaired cerebral and peripheral hemodynamic stabilization during active standing

Abstract

Background: Age-related morbidities and frailty are associated with impaired blood pressure (BP) and heart rate (HR) recovery after standing. Here we investigate how multimorbidity affects cerebral and peripheral hemodynamics during standing in a large sample of older patients.

Methods: Patients were recruited from a national Falls and Syncope Unit. They underwent an active stand test (5-10 min lying +3 min standing) with monitoring of continuous BP, HR, total peripheral resistance (TPR), stroke volume (SV), and a near-infrared spectroscopy (NIRS) derived cerebral tissue saturation index (TSI). A multimorbidity count was derived from a 26-item list of conditions. Features derived from the signals included: nadir, overshoot, value at 30 s, steady-state and recovery rate. Robust linear regression was used to assess the association between multimorbidity, TSI and peripheral hemodynamics while correcting for covariates. A p-value <0.05 was considered statistically significant.

Results: Multimorbidity was associated with poorer recovery of TSI at 30 s after standing (β: -0.15, CI:[-0.25-0.06], p = 0.009) independent of all peripheral hemodynamics. Impaired diastolic BP (DBP) recovery at 30s (β:-1.34, CI:[-2.29-0.40], p = 0.032), DBP steady-state (β:-1.18, CI:[-2.04-0.32], p = 0.032), TPR overshoot-to-nadir difference (β:-0.041, CI:[-0.070-0.013], p = 0.045), and SV at 30s (β:1.30, CI:[0.45 2.15], p = 0.027) were also associated with increasing multimorbidity. After sex stratification, only females demonstrated impaired TSI with multimorbidity at overshoot (β: -0.19, CI: [-0.32 -0.07], p = 0.009), 30 s (β: -0.22 [-0.35-0.10], p = 0.005) and steady-state (β: -0.20, CI:[-0.35-0.04], p = 0.023), independent of peripheral hemodynamics.

Conclusions: Transient cerebral oxygenation and peripheral hemodynamic responses are impaired with multimorbidity (frailty) in older patients, particularly in females. This study demonstrates the feasibility of using NIRS in this clinical context and may inform the development of clinical management strategies targeting both cerebral oxygenation and blood pressure impairments in patients with faints and falls.

Keywords: active standing; cerebral oxygenation; multimorbidity; near-infrared spectroscopy; orthostatic hypotension.

FIGURE 1

Features extracted from cerebral (TSI) and peripheral (SBP, DBP, HR) responses to an active standing test in a selected patient. Features extracted from the signals have been indicated. DBP, diastolic blood pressure; HR, heart rate; SBP, systolic blood pressure; TSI, tissue saturation index. Note that time is in seconds, and both TSI/SBP/DBP nadir and HR maximum occur within 15 s of standing (t = 0).

FIGURE 2

Absolute drops from baseline for cerebrovascular (TSI) and cardiovascular (SBP, DBP, HR) haemodynamics for all patients (left), females (middle) and males (right) during the active standing test for patients accumulating 2 or less morbidities (orange) and 5 or more morbidities (purple) (note that these categories were used only for the purpose of displaying the data, multimorbidity was analyzed as a continuous variable). Multimorbidity was associated with impaired TSI and DBP recovery, and an attenuated HR response in all patients and in the females cohort, while no associations were observed in males (after covariates adjustment). The start of the test has been indicated with a vertical line at t = 0. Error bars represent the confidence intervals of the mean at t = −30, 30, 60, 90, 120 and 150 s after standing. TSI, tissue saturation index; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; morb, morbidities.

FIGURE 3

Forest plot representing standardized β coefficients and confidence intervals for the association of multimorbidity and the different features derived from TSI, SBP, DBP, HR, TPR and SV for all patients (left), females (right, red squares) and males (right, green circles) in the multivariate model adjusting for: age + sex + BMI + baseline SBP + baseline HR + speed of standing + supine rest duration + alcohol excess + smoking status + antihypertensives + antidepressants. DBP, diastolic blood pressure; HR, heart rate; SBP, systolic blood pressure; TSI, tissue saturation index. *indicates p‐value <0.05 and **p‐value <0.01 after multiple comparison correction.