Reliability of orthostatic responses in healthy men aged between 65 and 75 years

Does gradual change in head positioning affect cerebrovascular physiology?

We studied cerebral blood velocity (CBV), and associated hemodynamic parameters during gradual changes in head positioning in a nonstroke group. CBV (transcranial Doppler ultrasound), beat-to-beat blood pressure (BP, Finometer), and end-tidal carbon dioxide (ETCO2 , capnography) were recorded between lying flat (0°) and sitting up (30°) head positions, in 18 volunteers (10 female, mean age, 57 ± 16 years), at two visits (12 ± 8 days). A significant reduction was found between 5-min FLAT (0°) and 5-min SIT (30°) positions in CBV (visit 1: 4.5 ± 3.3%, P = 0.006; visit 2: 4.1 ± 3.5%, P = 0.003), critical closing pressure (CrCP; visit 1: 15.5 ± 14.0%, P = 0.0002; visit 2: 14.1 ± 7.8%, P = 0.009) and BP (visit 1: 8.3 ± 7.4%, P = 0.001; visit 2: 11.0 ± 11.3%, P < 0.001). For 5 min segments of data, the autoregulation index and other hemodynamic parameters did not show differences either due to head position or visit. For 30 sec time intervals, significant differences were observed in the following: (BP, P < 0.001; dominant hemisphere (DH) CBV, P < 0.005; nondominant hemisphere (NDH) CBV, P < 0.005; DH CrCP, P < 0.001; NDH CrCP, P < 0.001; DH resistance area product (RAP), P = 0.002; NDH RAP, P = 0.033). Significant static changes in BP, CBV and CrCP, and large transient changes in key hemodynamic parameters occur during 0° to 30°, and vice versa, with reproducible results. Further studies are needed following acute ischemic stroke to determine if a similar responses is present.

Orthostatic hypotension and drug therapy in patients at an outpatient comprehensive geriatric assessment unit

OBJECTIVE

To assess the rate of orthostatic hypotension and factors associated with it among elderly patients who underwent a comprehensive, ambulatory geriatric assessment.

METHODS

The study included patients 65 years and older who were assessed in the outpatient comprehensive geriatric assessment unit. Data were collected from the computerized medical record including sociodemographic data, lifestyle, falls, blood pressure, BMI, functional and cognitive status, medications, and comorbidity.

RESULTS

The study population consisted of 571 patients who underwent assessment over a nine-year period. The mean age was 83.7 ± 6.1, 35.9% were men, and 183 (32.1%) were diagnosed with orthostatic hypotension. Multiple drugs, in general, and multiple drugs with the potential to cause orthostatic hypotension in particular increased the risk for orthostatic hypotension after adjustment for age, sex, chronic comorbidity, and supine systolic blood pressure ≥150 mmHg [odds ratio (OR) = 1.09, 95% confidence interval (CI): 1.03-1.14 and OR = 1.22, 95% CI: 1.08-1.37, respectively]. In addition, α-blockers and calcium channel blockers increased the risk for orthostatic hypotension after similar adjustments (OR = 1.82, 95% CI: 1.01-3.16 and OR = 1.66, 95% CI: 1.11-2.48, respectively). Similarly, two additional drug types increased the risk for orthostatic hypotension: selective serotonin reuptake inhibitors (OR = 2.09, 95% CI: 1.33-3.19) and tricyclic antidepressants (OR = 4.36, 95% CI: 1.85-10.06). There were no specific associations between age, cognitive and functional state, morbidity (as measured by the Charlson Comorbidity Index), and specific diseases, and orthostatic hypotension.

CONCLUSION

The results of the present study reinforce evidence of an association between drug therapy and orthostatic hypotension.

Prevalence of orthostatic hypotension in the unselected ambulatory population of persons aged 65 years old and above

BACKGROUND

The diagnostic recommendation for orthostatic hypotension (OH) is to measure blood pressure during the first 3 min after getting up from a lying position. There are no clear definitions as to the amount of time that the patient should lie down before this, and the number of measurements to be taken in lying and standing positions. The aim of this study was to identify the optimal time to measure blood pressure when lying and standing.

METHODS

This was a prospective study of 99 patients aged 65 years and above in an urban primary care clinic. Blood pressure was measured at 1 min intervals over 10 min in the lying position and 7 min standing.

RESULTS

OH was found in 37 patients (37.4%). Of these, 56.8% were identified in the 1st minute, 67.6% after 2 min and 83.8% after 3 min of standing. In all cases, participants with OH were asymptomatic. In the lying position, blood pressure stabilized after 7 min, but when the 7th minute was used as a reference for OH many cases were lost.

CONCLUSION

To optimize the identification of OH, blood pressure should be measured at 1 min intervals over the first 3 min after standing up. The amount of time that patients should lie down before blood pressure is measured standing up still has to be determined.

Reliability of the sit-up test in individuals with spinal cord injury

OBJECTIVE

To determine the day-to-day reliability of blood pressure responses during a sit-up test in individuals with a traumatic spinal cord injury (SCI).

DESIGN

Within-subject, repeated measures design.

SETTING

Community outpatient assessments at a research laboratory at the University of British Columbia.

PARTICIPANTS

Five men and three women with traumatic SCI (age: 31 ± 6 years; C4-T11; American Spinal Injury Association Impairment Scale A-B; 1-17 years post-injury).

OUTCOME MEASURE

Maximum change in systolic (ΔSBP) and diastolic (ΔDBP) blood pressure upon passively moving from a supine to seated position.

RESULTS

The average values for ΔSBP were -11 ± 13 mmHg (range -38 to 3 mmHg) for visit 1, and -12 ± 8 mmHg (range -26 to -1 mmHg) for visit 2. The average values for ΔDBP were -9 ± 8 mmHg (range -21 to 0 mmHg) for visit 1, and -13 ± 8 mmHg (range -29 to -3 mmHg) for visit 2. The ΔSBP demonstrated substantial reliability with an intraclass correlation coefficient of 0.79 (P = 0.006; 95% CI 0.250-0.953), while the ΔDBP demonstrated almost perfect reliability with an intraclass correlation coefficient of 0.92 (P < 0.001; 95% CI 0.645-0.983). The smallest detectable differences in ΔSBP and ΔDBP were 7 mmHg and 6 mmHg, respectively.

CONCLUSION

Blood pressure responses to the sit-up test are reliable in individuals with SCI, which supports its implementation as a practical bedside assessment for orthostatic hypotension in this at risk population.

Persistence and Prognostic Implications of Orthostatic Hypotension in Older Individuals with Mild-to-Moderate Dementia

AIM

To study the course and prognostic implications of orthostatic hypotension (OH) in older individuals with mild-to-moderate dementia.

METHODS

Referrals to outpatient clinics specialising in old age psychiatry and geriatric medicine in the counties of Rogaland and Hordaland in western Norway with a first-time diagnosis of mild dementia were consecutively asked for inclusion. A total of 211 participants underwent a comprehensive baseline assessment with annual follow-ups. Patients with OH at both baseline and the 1-year follow-up were classified as having persistent OH. Outcome measures were the Mini-Mental State Examination (MMSE), the Clinical Dementia Rating sum of boxes (CDR-SB), and time to death.

RESULTS

From baseline to the 4-year follow-up, 30-45% of the participants had OH at each follow-up. In multivariable analysis, persistent OH was not significantly associated with either the longitudinal course of MMSE or CDR-SB scores or survival.

CONCLUSIONS

OH was moderately prevalent over 4 years in older individuals with mild dementia, and persistent OH did not predict either cognitive or functional decline or survival.

Orthostatic hypotension in Parkinson’s disease

SUMMARY Orthostatic hypotension (OH) is a frequent non-motor symptom in Parkinson’s disease (PD), affecting between 22.9 and 38.4% of patients. In PD, OH is related to an increased risk of falls, and possibly to cognitive dysfunction and increased mortality. These data emphasize the importance of its prompt recognition and treatment. OH is related to pre- and post-ganglionic adrenergic denervation, but other factors, such as drugs, heat, meals or alcohol intake, might also induce or aggravate it. Evidence about the efficacy and safety of pharmacological or nonpharmacological strategies for OH treatment in PD is weak. Nonpharmacological measures include liberal addition of salt to the diet, exercise, compression stockings or physical maneuvers. Severe cases may be treated with midodrine or fludrocortisone. Some results suggest that droxidopa and fipamezole may be effective treatments. We finish this review article by discussing the most important unanswered questions about PD-related OH, which may be the focus of future research.

The clinical assessment of orthostatic hypotension

Orthostatic hypotension is a common condition seen in up to one-third of community-dwelling and two-thirds of hospitalized older people. It is part of a spectrum of abnormal cardiovascular responses to postural challenge and is associated with syncope, dizziness, falls, volume depletion, drug side-effects and an increased mortality. This article discusses the current classification of orthostatic hypotension and related conditions, and the clinical importance of the control of the cardiovascular response to orthostasis. These are considered with particular reference to the measurement of postural cardiovascular responses in the routine clinical setting. By improving understanding of the methods that are used for assessment of postural changes in blood pressure, clinicians should have greater confidence in the reliability of measurement and in their interpretation.

Withdrawal of fall-risk-increasing drugs in older persons: effect on tilt-table test outcomes

OBJECTIVES

To determine whether outcomes of tilt-table tests improved after withdrawal of fall-risk-increasing drugs (FRIDs).

DESIGN

Prospective cohort study.

SETTING

Geriatric outpatient clinic.

PARTICIPANTS

Two hundred eleven new, consecutive outpatients, recruited from April 2003 until December 2004.

MEASUREMENTS

Tilt-table testing was performed on all participants at baseline. Subsequently, FRIDs were withdrawn in all fallers in whom it was safely possible. At a mean follow-up of 6.7 months, tilt-table testing was repeated in 137 participants. Tilt-table testing addressed carotid sinus hypersensitivity (CSH), orthostatic hypotension (OH), and vasovagal collapse (VVC). Odds ratios (ORs) of tilt-table-test normalization according to withdrawal (discontinuation or dose reduction) of FRIDs were calculated using multivariate logistic regression analysis.

RESULTS

After adjustment for confounders, the reduction of abnormal test outcomes (ORs) according to overall FRID withdrawal was 0.34 (95% confidence interval (CI)=0.06-1.86) for CSH, 0.35 (95% CI=0.13-0.99) for OH, and 0.27 (95% CI=0.02-3.31) for VVC. For the subgroup of cardiovascular FRIDs, the adjusted OR was 0.13 (95% CI=0.03-0.59) for CSH, 0.44 (95% CI=0.18-1.0) for OH, and 0.21 (95% CI=0.03-1.51) for VVC.

CONCLUSION

OH improved significantly after withdrawal of FRIDs. Subgroup analysis of cardiovascular FRID withdrawal showed a significant reduction in OH and CSH. These results imply that FRID withdrawal can cause substantial improvement in cardiovascular homeostasis. Derangement of cardiovascular homeostasis may be an important mechanism by which FRID use results in falls.