336 ASYMPTOMATIC ORTHOSTATIC HYPOTENSION AND RISK OF FALLS IN COMMUNITY-DWELLING OLDER PEOPLE

Background

Many older people with Orthostatic Hypotension (OH) may not report typical symptoms of dizziness, light-headedness, or unsteadiness. However, the relationships between OH and falls in the absence of typical symptoms are not yet established.

Methods

Continuous orthostatic BP was measured during active stand using a Finometer at Wave 1 of TILDA in participants aged≥70 years. OH, with and without dizziness, was defined as a sustained drop in systolic BP≥20 and/or diastolic BP≥10 mm Hg at 30, 60 and 90 seconds post-standing. The association between symptoms of dizziness and orthostatic BP was assessed with multi-level mixed-effects linear regression; logistic regression models assessed the longitudinal relationship between OH and falls at 6-year follow-up (Waves 2-5).

Results

Almost 11% (n=934; mean age: 75 years; 51% female) had OH, two-thirds of whom were asymptomatic. Dizziness was not associated with systolic BP drop at 30 (β=1.54; –1.27, 4.36; p=0.256), 60 (β=2.6; –0.19, 5.47; p =0.476) or 90 (β=2.02; –0.91, 4.95; p=0.176) seconds after standing in adjusted models. Asymptomatic OH was independently associated with unexplained falls (Odds Ratio: 2.01; 1.11, 3.65; p=0.022) but not explained falls (OR 0.93; 0.53, 1.62; p=0.797) during follow-up.

Conclusion

Two-thirds of older people with OH did not report typical symptoms of light-headedness. Dizziness or unsteadiness after standing did not correlate with the degree of orthostatic BP drop or recovery. Participants with asymptomatic OH had a significantly higher risk of unexplained falls during follow-up, and this has important clinical implications for the assessment of older people with falls.

204 FRAILTY BUT NOT AGE IS ASSOCIATED WITH IMPAIRED ORTHOSTATIC CEREBRAL OXYGENATION

Background

The effects of age and frailty on cerebrovascular function are poorly understood. Here we investigate the hypotheses that aging, and frailty are accompanied by impaired regulation of cerebral oxygenation during standing in a patient population of older adults.

Methods

We recruited patients from a national Falls and Syncope service. All patients underwent an active stand test (5–10 min lying, 3 min standing) with continuous monitoring of blood pressure (BP) and heart rate. Tissue saturation index (TSI) was concurrently measured using near-infrared spectroscopy and its recovery measured at 30s after standing. Frailty was assessed as a comorbidity count using a 27-item questionnaire. Robust linear regression was used to investigate the association between TSI, age and frailty in a multivariate model with covariate adjustment, including the concurrent BP values. A p-value <0.05 was considered significant.

Results

304 patients (median(IQR): 71(14) years, 57% females) were recruited. Age was not associated with cerebral oxygenation after standing (β: −0.001 (−0.017 0.015), p = 0.899), even after stratification by sex (males: β: −0.010 (−0.045 0.024), p = 0.558, females: β: 0.000 (−0.017 0.018), p = 0.967). Frailty, was associated with a lower TSI at 30s after standing (β: −0.153 (−0.248–0.058), p = 0.002). After sex stratification, no associations with frailty were observed in males (β: −0.052 (−0.226 0.123), p = 0.557), while frailer females demonstrated a lower TSI at 30 seconds after standing (β: −0.179 (−0.294–0.063), p = 0.003) despite BP correction.

Conclusion

Our results suggest alternative mechanisms of cerebral oxygenation regulation independent of blood pressure (and presumably cerebral autoregulation) are involved in frailty related impairments of brain haemodynamics which are also independent of ageing. Such impairments represent novel biomarkers of frailty and represent potentially novel modifiable risk factors (independent of BP management) of hypoperfusion related disorders in clinical ageing.

239 IS ORTHOSTATIC HYPOTENSION ASSOCIATED WITH ALTERED CEREBRAL PERFUSION DURING ACTIVE STANDING?

Background

Orthostatic Hypotension (OH) is associated with poor health outcomes in later life including depression, cognitive impairment, frailty and falls. Whilst it is hypothesised that OH compromises cerebral autoregulation leading to hypoperfusion, this has not been robustly demonstrated to date. This study investigated the association between OH and cerebral perfusion during orthostasis using a non-invasive surrogate of cerebral perfusion, Near Infrared Spectroscopy (NIRS).

Methods

Four hundred and ninety one participants (58% female, median age 65, IQR 38–92) attending a falls and syncope service underwent measurement of beat-to-beat blood pressure (BP) by finometry and real-time frontal lobe perfusion (% TSI: Tissue Saturation Index) by NIRS during the active stand manoeuvre. We examined the association between OH and change in cerebral perfusion (delta TSI) using mixed-effects linear regression, with adjustment for important clinical covariates.

Results

Nearly two-fifths of the sample (189/491,38.5%) met criteria for OH occurring between 30 and 120 seconds after standing. Using mixed effects linear regression models, we observed a significant relationship between OH and TSI at the same timepoint (β −0.53, −0.59 to −0.46, p < 0.001) which persisted following adjustment for confounders including age, sex, baseline blood pressure, cerebrovascular and cardiovascular disease, depression/anxiety, diabetes, systolic blood pressure, antihypertensives, and antidepressants (β −0.51, −0.58 to −0.44, p < 0.001). Cerebral perfusion levels differed for those with OH compared to those without.

Conclusion

OH is independently associated with lower frontal lobe cerebral perfusion. This association may indicate disruption to dynamic cerebral autoregulation and explain the significant link between OH and poor health outcomes.

Near-infrared spectroscopy in evaluating psychogenic pseudosyncope-a novel diagnostic approach

BACKGROUND

Psychogenic pseudosyncope (PPS), a conversion disorder and syncope mimic, accounts for a large proportion of 'unexplained syncope'. PPS is diagnosed by reproduction of patients' symptoms during head-up tilt (HUT). Electroencephalogram (EEG), a time consuming and resource intensive technology, is used during HUT to demonstrate absence of cerebral hypoperfusion during transient loss of consciousness (TLOC). Near-infrared spectroscopy (NIRS) is a simple, non-invasive technology for continuous monitoring of cerebral perfusion. We present a series of patients for whom PPS diagnosis was supported by NIRS during HUT.

METHODS

Eight consecutive patients with suspected PPS referred to a syncope unit underwent evaluation. During HUT, continuous beat-to-beat blood pressure (BP), heart rate (HR) and NIRS-derived tissue saturation index (TSI) were measured. BP, HR and TSI at baseline, time of first symptom, presyncope and apparent TLOC were measured. Patients were given feedback and followed for symptom recurrence.

RESULTS

Eight predominantly female patients (6/8, 75%) aged 31 years (16-54) were studied with (5/8, 63%) having comorbid psychiatric diagnoses, and (5/8, 63%) presenting with frequent episodes of prolonged TLOC with eyes closed (6/8, 75%). All patients experienced reproduction of typical events during HUT. Systolic BP (mmHg) increased from baseline (129.7 (interquartile range [IQR] 124.9-133.4)) at TLOC (153.0 (IQR 146.7-159.0)) (P-value = 0.012). HR (bpm) increased from baseline 78 (IQR 68.6-90.0) to 115.7 (IQR 93.5-127.9) (P-value = 0.012). TSI (%) remained stable throughout, 71.4 (IQR 67.5-72.9) at baseline vs. 71.0 (IQR 68.2-73.0) at TLOC (P-value = 0.484).

CONCLUSIONS

NIRS provides a non-invasive surrogate of cerebral perfusion during HUT. We propose HUT incorporating NIRS monitoring in the diagnostic algorithm for patients with suspected PPS.