Orthostatic hypotension and cognitive decline in older people

Orthostatic hypotension in Parkinson's disease: association with cognitive decline?

BACKGROUND

Orthostatic hypotension is common in Lewy body disorders and may be related to disease progression and the spread of Lewy body pathology. We therefore hypothesize that PD patients with orthostatic hypotension (OH) have a different cognitive profile compared to PD patients without OH.

METHODS

This cross-sectional study included 175 PD patients. Blood pressure (BP) was measured with a validated digital blood pressure monitor and patients with a systolic BP drop of > or =20 mmHg or a systolic pressure of <90 mm Hg after standing were considered to have OH. Cognition was assessed using MMSE extended by a selection of computerized cognitive tests focusing on reaction time, sustained attention, working memory and episodic verbal and visual memory.

RESULTS

Eighty-seven (49.7%) of the PD patients had OH. These patients were significantly more impaired in sustained attention and visual episodic memory compared to PD patients without OH.

CONCLUSION

We conclude that there are differences in the neuropsychological performance of patients with PD and OH, supporting the hypothesis that OH might be a marker for disease progression and cognitive decline in PD.

Influence of orthostatic hypotension on mortality among patients discharged from an acute geriatric ward

BACKGROUND

Orthostatic hypotension (OH) is a common finding among older patients. The impact of OH on mortality is unknown.

OBJECTIVE

To study the long-term effect of OH on total and cardiovascular mortality.

PATIENTS AND METHODS

A total of 471 inpatients (227 males and 244 females), with a mean age of 81.5 years who were hospitalized in an acute geriatric ward between the years 1999 and 2000 were included in the study. Orthostatic tests were performed 3 times during the day on all patients near the time of discharge. Orthostatic hypotension was defined as a fall of at least 20 mmHg in systolic blood pressure (BP) and/or 10 mmHg in diastolic BP upon assuming an upright posture at least twice during the day. Patients were followed until August 31, 2004. Mortality data were taken from death certificates.

RESULTS

One hundred and sixty-one patients (34.2%) experienced OH at least twice. Orthostatic hypotension had no effect on all cause and cause specific mortality. Over a follow-up of 3.47+/-1.87 years 249 patients (52.8%) had died 83 of whom (33.3%) had OH. Age-adjusted mortality rates in those with and without OH were 13.4 and 15.7 per 100 person-years, respectively. Cox proportional hazards model analysis demonstrated that male gender, age, diabetes mellitus, and congestive heart failure increased and high body mass index decreased total mortality.

CONCLUSIONS

Orthostatic hypotension is relatively common in elderly patients discharged from acute geriatric wards, but has no impact on vascular and nonvascular mortality.

Cardiovascular dysautonomia as a cause of falls in Parkinson's disease

Parkinson's disease (PD) patients have a ninefold increased risk of recurring falls compared to healthy controls. The risk of falling due to cardiovascular dysautonomia (CVD) is not quantifiable. But, CVD is an integral part of the disease and at least 20% of PD patients suffer from orthostatic hypotension, an expression of CVD. One way to reduce falls due to CVD in PD patients could be to give adequate information on the relationship between falling risks and cardiovascular dysautonomia to patients and their caregivers. Moreover, drugs given for PD might contribute to OH and we propose that education and non-pharmacological strategies for its treatment might be preferable, especially because of the low efficacy of drugs available for the treatment of OH and the frailty of elderly PD patients.

Orthostatic systolic hypotension and the reflection pressure wave

Orthostatic hypotension (OH) is a potent predictor of cardiovascular frailty. Although OH is determined by changes in brachial blood pressure (BP), it has been reported that there are significant differences between central BP and peripheral BP. The prevalence of OH has been reported to be higher in subjects with isolated systolic hypertension. Since an early returning of the reflection pressure wave due to advanced arterial stiffness is one of the underlying mechanisms of systolic hypertension, a significant association between alterations of the reflection pressure wave and OH has been hypothesized. To explore this hypothesis, the orthostatic changes in carotid BP and arterial waveform were evaluated. The study subjects were 155 community residents (69 +/- 7 years old). Carotid and brachial BP were measured simultaneously in the supine position and 1 min after standing using a cuff-oscillometric and tonometric method. The carotid augmentation index (AIx) was obtained from the pressure waveform. The orthostatic decline of BP was more prominent in the carotid artery than the brachial artery. Nine subjects were diagnosed with orthostatic systolic hypotension (OSH) from brachial BP, while 21 subjects were diagnosed from carotid BP (p < 0.001). The orthostatic change in carotid systolic BP was significantly associated with that in carotid AIx (r = 0.361, p < 0.001). The decline of the reflection component of carotid pulse pressure (-4.0 +/- 8.4 mmHg) was more prominent than that of the incident component (-1.2 +/- 9.9 mmHg, p = 0.002). These results indicate that evaluation of brachial BP may not represent the orthostatic changes in central BP. Alteration of the reflection pressure wave could be one of the underlying mechanisms of OSH in the central artery.

Association between supine cerebral perfusion and symptomatic orthostatic hypotension

The goal of this study was to investigate whether the supine resting perfusion of brain tissue in symptomatic patients suffering from orthostatic hypotension (OH) is changed compared to control subjects and whether an association exists between the resting perfusion and the severity of OH. Ten symptomatic OH patients and 8 control subjects were included in this study. One patient was retrospectively excluded because he suffered from multiple system atrophy. Systolic and diastolic blood pressure changes were measured during a tilting bed procedure. Cerebral blood flow, cerebral blood volume and mean transit time were determined by bolus-tracking perfusion MRI and correlated with blood pressure changes. Cerebral blood volume was significantly increased in OH patients compared with control subjects for white matter (P = 0.019) and the mean transit time was significantly increased for gray (P = 0.010) and white matter (P = 0.015). The cerebral blood flow of the gray (r = 0.74, P = 0.022) and white matter (r = 0.75, P = 0.020) was significantly, positively correlated with systolic blood pressure changes. The mean transit time in white matter was significantly, negatively correlated with systolic blood pressure changes (r = -0.68, P = 0.045). This study suggests that in symptomatic patients with OH the cerebral perfusion of the brain in the resting, supine position correlates with the severity of OH as measured by postural changes in blood pressure.

Effect of blood pressure on cognitive functions in elderly persons

BACKGROUND

Little is known about what specific cognitive functions are affected by elevated blood pressure (BP) and how orthostatic BP change is related to cognitive impairment. The aim of this study was to determine the effect of BP and its postural change on cognitive functions in otherwise healthy elders.

METHODS

In 70 healthy persons (mean age, 72 +/- 4 years), supine systolic BP (SBP) was assessed 3 times using a sphygmomanometer, and the average values were obtained for the analysis. After 1, 3, and 5 minutes of standing, 3 BP measurements were obtained and the orthostatic SBP changes were determined by subtracting these values from the supine average. Neuropsychological tests were administered to assess short-term and long-term verbal and visual memory, visuospatial skills, and frontal-executive functions. Participants were considered impaired in the specific cognitive performance if their scores fell below the 25th percentile of the study population. Multiple logistic regression models were used to evaluate the relation of SBP and the magnitude of orthostatic SBP decline to risk for impairment in each of the cognitive tests.

RESULTS

Controlling for potential confounders, each 10 mmHg increase in supine SBP was associated with a 2.31-fold increase (95% confidence interval, 1.14 to 4.66) in risk for impairment in psychomotor speed and set shifting as measured using the Trailmaking Part-B test. There was no significant association between cognitive functions and orthostatic SBP decline at 1, 3, and 5 minutes of standing.

CONCLUSION

Elevation of BP is associated with a selective impairment in executive function in otherwise healthy community-dwelling elders.

Postural Blood Pressure Changes and Orthostatic Hypotension in the Elderly Patient

With age our ability to maintain haemodynamic homeostasis during position changes becomes less effective. This predisposes elderly patients to significant changes in blood pressure upon standing and orthostatic hypotension (OH). The prevalence of OH varies according to the population being studied. A range of between 5% and 60% has been reported with the lower rate in elderly individuals living in the community and higher rates in those living in an institution or in the acute-care setting. Multiple factors have been linked to OH including age, bed rest, low body mass index and medications. Although antihypertensive medications can theoretically, as a group, worsen OH, the majority of cross-sectional studies have found no association. In addition, prospective randomised trials have demonstrated an improvement in postural blood pressure (PBP) changes with antihypertensive medications. When considering the individual classes, peripheral vasodilators, specifically alpha-adrenoceptor antagonists and nondihydropyridine calcium channel antagonists, can exacerbate PBP changes and lead to OH. ACE inhibitors, angiotensin-receptor antagonists and beta-adrenoceptor antagonists with intrinsic sympathomimetic activity are less likely to worsen OH. Careful management of electrolyte disturbance can decrease the risk of developing OH with diuretic use. With the aging population, this problem will be encountered by the clinicians at a much higher rate. A detailed patient history, an accurate orthostatic blood pressure measurement and careful evaluation of the autonomic nervous system can provide clinical guidance for management of OH. In hypertensive individuals with no pre-treatment OH, the use of antihypertensive medication can be safe and lead to a low risk of developing OH. In individuals with pre-treatment OH or who develop OH while on antihypertensive medications avoidance of the classes that may exacerbate OH and a judicious use of antihypertensive classes that may improve PBP changes may be safe and adequate treatment.

A systematic review of cognitive decline in the general elderly population

BACKGROUND

The public health impact of cognitive decline and dementia is increasing as the population ages. Studies exploring therapies or risk factors for cognitive impairment require understanding of expected age-related decline.

OBJECTIVE

To establish the rate of age-related cognitive decline in the general elderly population.

DESIGN

Systematic review of studies of cognitive decline in the general elderly population. Medline, Embase and PsycINFO databases were searched using an adapted version of McMaster's aetiology, causation and harm strategies and the Cochrane Dementia and Cognitive Impairment Group strategy. Grey literature was explored and experts contacted. A second observer was involved at all stages and quality appraisal of included studies was performed. Included studies were representative, community-based, cohort studies of people aged over 60, incorporating individuals with dementia.

RESULTS

Identification of 5990 abstracts and retrieval of 163 full texts led to inclusion of 19 papers. Heterogeneity made narrative review the appropriate method of data synthesis. Some degree of cognitive impairment with increasing age was found in all studies, although the extent varied. The prevalence of cognitive impairment and the rate of decline increased with age. Studies were of variable quality.

CONCLUSIONS

Cognitive decline is almost universal in the general elderly population and increases with age. Improved communication between researchers and between clinicians to identify a core minimum data set of neuropsychological tests that could be used in different populations would support consistent study design and meta-analysis, helping to quantify the true rate of cognitive decline in the elderly and assisting diagnosis in clinical practice.

Temazepam, but not zolpidem, causes orthostatic hypotension in astronauts after spaceflight

Insomnia is a common symptom, not only in the adult population but also in many astronauts. Hypnotics, such as temazepam (a benzodiazepine) and zolpidem (an imidazopyridine), are often taken to relieve insomnia. Temazepam has been shown clinically to have hemodynamic side effects, particularly in the elderly; however, the mechanism is not clear. Zolpidem does not cause hemodynamic side effects. The purpose of this study was to determine whether the use of different hypnotics during spaceflight might contribute significantly to the high incidence of postflight orthostatic hypotension, and to compare the findings in astronauts with clinical research. Astronauts were separated into three groups: control (n = 40), temazepam (15 or 30 mg; n = 9), and zolpidem (5 or 10 mg; n = 8). In this study, temazepam and zolpidem were only taken the night before landing. The systolic and diastolic blood pressures and heart rates of the astronauts were measured during stand tests before spaceflight and on landing day. On landing day, systolic pressure decreased significantly and heart rate increased significantly in the temazepam group, but not in the control group or in the zolpidem group. Temazepam may aggravate orthostatic hypotension after spaceflight when astronauts are hemodynamically compromised. Temazepam should not be the initial choice as a sleeping aid for astronauts. These results in astronauts may help to explain the hemodynamic side effects in the elderly who are also compromised. Zolpidem may be a better choice as a sleeping aid in these populations.

Orthostatic hypotension

A common problem among elderly people, orthostatic hypotension is associated with significant morbidity and mortality, which may be caused by medications, the cumulative effects of age- and hypertension-related alterations in blood pressure regulation, or age-associated diseases that impair autonomic function. Evaluation requires multiple blood pressure measurements taken at different times of the day and after meals or medications. Central and peripheral nervous system disorders should be sought, and the laboratory evaluation should concentrate on ruling out diabetes mellitus, amyloidosis, occult malignancy, and vitamin deficiencies. If orthostatic hypotension is detected, it should be considered a risk factor for adverse outcomes and treated first with nonpharmacologic interventions, including the withdrawal of potentially hypotensive medications. In patients with hypertension and orthostatic hypotension, the judicious treatment of hypertension may be helpful. For persistent, symptomatic orthostatic hypotension caused by autonomic failure, pharmacologic interventions include fludrocortisone, midodrine, and a variety of other agents. The careful evaluation and management of orthostatic hypotension will hopefully result in a significant reduction in falls, syncope, and fractures, and an attenuation of functional decline in elderly patients.