Cerebral oxygenation responses to standing in elderly patients with predominantly diastolic dysfunction

Abstract

Patients with left ventricular dysfunction may have different orthostatic responses of blood pressure (BP) and cerebral oxygenation than healthy elderly subjects. We investigated orthostatic changes in systemic haemodynamic variables and cerebral oxygenation in 21 elderly patients with heart failure New York Heart Association class I-III in stable condition (age 70-83 years) after withdrawal of furosemide and captopril for 2 weeks, and in 18 healthy elderly subjects (age 70-84 years). Frontal cortical concentration changes of oxyhaemoglobin ([O2Hb]) and deoxyhaemoglobin ([HHb]) were continuously measured by near-infrared spectrophotometry and BP changes by Finapres before and during 10 min of standing. Upon standing [O2Hb] reflecting blood flow, changed by -1.2 +/- 0.9 micromol L-1 (mean +/- SEM) in the patients, whereas it decreased by -4.5 +/- 0.6 micromol L-1 (P<0.01) in the healthy subjects after standing (P<0.05 between groups). [HHb] reflecting the sum of cerebral blood flow, arterial oxygen saturation and cerebral oxygen uptake, increased by 1.5 +/- 0.5 micromol L-1 (P<0.05) and 1.7 +/- 0.6 micromol L-1 (P<0.05), respectively. Compared with healthy elderly subjects, elderly patients with left ventricular dysfunction showed smaller orthostatic [O2Hb] decreases (P<0.01), in relation to higher orthostatic BP rises (P<0.05). These findings indicate that BP changes and an altered cardiovascular balance may influence orthostatic cortical haemodynamic responses in elderly subjects.

Impaired cerebral oxygenation in heart failure patients at rest and during head‐up tilt testing

“…The lower SctO 2 among HF patients compared with controls, both at rest and during orthostatic provocation, supports the hypothesis of increased susceptibility to cerebral hypoperfusion during orthostatic stress in HF 9 . In contrast to the current study, NIRS performed on elderly patients with diastolic dysfunction during 10 min of standing revealed that HF patients exhibited a smaller decrease in SctO 2 compared with healthy elderly subjects 20 . The fact that the latter study required withdrawal of furosemide and captopril prior to tests, which may benefit the haemodynamic response to orthostasis, 21 may explain the conflicting results.…”

“…The fact that the latter study required withdrawal of furosemide and captopril prior to tests, which may benefit the haemodynamic response to orthostasis, 21 may explain the conflicting results. In addition, the latter study included patients with normal left ventricular EF 20 as opposed to the current study which included patients with both preserved, mid‐range, and reduced EF.…”

“…9 In contrast to the current study, NIRS performed on elderly patients with diastolic dysfunction during 10 min of standing revealed that HF patients exhibited a smaller decrease in SctO 2 compared with healthy elderly subjects. 20 The fact that the latter study required withdrawal of furosemide and captopril prior to tests, which may benefit the haemodynamic response to orthostasis, 21 may explain the conflicting results. In addition, the latter study included patients with normal left ventricular EF 20 as opposed to the current Figure 2 Changes in systolic blood pressure, heart rate, and cerebral tissue oxygen saturation during head-up tilt testing.…”

“…20 The fact that the latter study required withdrawal of furosemide and captopril prior to tests, which may benefit the haemodynamic response to orthostasis, 21 may explain the conflicting results. In addition, the latter study included patients with normal left ventricular EF 20 as opposed to the current Figure 2 Changes in systolic blood pressure, heart rate, and cerebral tissue oxygen saturation during head-up tilt testing. Mean cerebral tissue saturation (SctO 2 ) in heart failure patients (solid black lines) and controls (dashed black lines) in relation to systolic blood pressure (SBP; in blue) and heart rate (HR; in red) during head-up tilt test.…”

Effect of age on brain oxygenation regulation during changes in position

“…In this setting, modest hypotension or hypocapnia can accentuate brain hypoxic changes (Enlund et al, 1989;Hampson et al, 1990;Torella and McCollum, 2004). However, pathophysiological factors that may magnify this effect are unclear (Artru et al, 1998;Mehagnoul-Schipper et al, 2003). Recent studies suggest that patients with low baseline brain hemoglobin concentrations have a compromised ability to maintain an adequate brain oxygenation state during modest hypotension (Paisansathan et al, in press).…”