Baroreflex function, haemodynamic responses to an orthostatic challenge, and falls in haemodialysis patients

Abstract

BackgroundStage 5 chronic kidney disease patients on haemodialysis (HD) often present with dizziness and pre-syncopal events as a result of the combined effect of HD therapy and cardiovascular disease. The dysregulation of blood pressure (BP) during orthostasis may be implicated in the aetiology of falls in these patients. Therefore, we explored the relationship between baroreflex function, the haemodynamic responses to a passive orthostatic challenge, and falls in HD patients.MethodsSeventy-six HD patients were enrolled in this cross-sectional study. Participants were classified as “fallers” and “non-fallers” and completed a passive head up tilting to 60o (HUT-60°) test on an automated tilt table. ECG signals, continuous and oscillometric BP measurements and impedance cardiography were recorded. The following variables were derived from these measurements: heart rate (HR) stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), number of baroreceptor events, and baroreceptor effectiveness index (BEI).ResultsThe forty-four participants who were classified as fallers (57.9%) had a lower number of baroreceptor events (6.5±8.5 vs 14±16.7, p = .027) and BEI (20.8±24.2% vs 33.4±23.3%, p = .025). In addition, fallers experienced a significantly larger drop in systolic (-6.4±10.9 vs -0.4±7.7 mmHg, p = .011) and diastolic (-2.7±7.3 vs 1.8±6 mmHg, p = .027) oscillometric BP from supine to HUT-60° compared with non-fallers. None of the variables taken for the analysis were significantly associated with falls in multivariate logistic regression analysis.ConclusionsThis cross-sectional comparison indicates that, at rest, HD patients with a positive history of falls present with a lower count of baroreceptor sequences and BEI.Short-term BP regulation warrants further investigation as BP drops during a passive orthostatic challenge may be implicated in the aetiology of falls in HD.

Multimodal Monitoring of Cardiovascular Responses to Postural Changes

“…Furthermore, the baroreflex (i.e., change in interval between heart beats as a response to BP changes) and cerebral autoregulation (CAR, i.e., regulation of cerebral blood flow during BP changes) are mechanisms that potentially attenuate the clinical consequences of OH and are therefore essential to understand the relationship between OH and clinical outcome (James and Potter, 1999;Mehagnoul-Schipper et al, 2000;Saint Martin et al, 2013;Tarumi et al, 2014;Ziegler, 2018). BRS and CAR are not addressed during regular clinical BP measurements (Mol et al, 2018c;Zanotto et al, 2018). There is therefore a need for continuous, unobtrusive, simultaneous assessment of orthostatic BP, baroreflex sensitivity (BRS) and CAR, which cannot be performed using the devices currently used in clinical practice.…”

The relative importance of frailty, physical and cardiovascular function as exercise-modifiable predictors of falls in haemodialysis patients: a prospective cohort study

“…Additionally, the relatively short duration of HUT-60°m ay be partially responsible for the apparent lack of difference in BP response during the orthostatic challenge in fallers compared with non-fallers (Table 4). Particularly, the five-minute HUT-60°protocol employed in this study was designed to investigate only the short-lived haemodynamic adjustments to orthostasis [18,47]. Previous research has shown that, during a 15-min passive orthostatic challenge, elderly people with a history of falls tend to exhibit a larger drop of BP compared with nonfallers [39].…”

“…Along with frailty, cardiovascular disease (CVD) is also highly prevalent in CKD-5 patients and impaired cardiovascular function is associated with multiple adverse clinical outcomes [16]. A few studies have also begun to better explore the link between clinical outcomes such as falls and cardiovascular dysregulation in this patient group [5,17,18]. In particular, it appears that the CKD-5 population on dialysis may be at risk of hypotension that can lead to postural dizziness, and potentially falls.…”

“…Two studies reported that low pre-dialysis blood pressure (BP) was associated with increased odds of falling [2,19], and a recent investigation by Kono et al [15] highlighted a significant relationship between intra-dialytic hypotension and falls in HD patients. In addition, we recently postulated that a drop in BP in response to a passive orthostatic challenge, as well as impaired baroreflex function may be linked to an increased risk of falling in HD patients [18]. All of these observations seem to indirectly suggest that impaired BP control, to maintain haemodynamic stability, might be implicated as an additional factor in the aetiology of falls in the CKD-5 population on dialysis, due to the CKD-related autonomic failure and/or the dialysis-related hypotension.…”

“…The arterial baroreflex was assessed during quiet rest (in supine position) and in response to a five-minute headup tilt test at 60°(HUT-60°) [18]. The Task Force Monitor 3040i (CNSystems, Graz, Austria), was used for the non-invasive measurement of all haemodynamic and baroreflex variables [30][31][32].…”