Orthostatic hypotension in Parkinson's disease: Sit-to-stand vs. supine-to-stand protocol and clinical correlates

BACKGROUND

Screening for orthostatic hypotension (OH) is integral in Parkinson's disease (PD) management, yet evidence-based guidelines on best practice methods for diagnosing OH in PD are lacking.

METHODS

We investigated the frequency and correlates of OH, symptomatic OH, and neurogenic OH, in a large consecutively recruited PD cohort (n = 318), and compared the diagnostic performance of the sit-to-stand vs. the supine-to-stand blood pressure (BP) test. We evaluated the utility of continuous BP monitoring and tilt table testing in patients with postural symptoms or falls who were undetected to have OH with clinic-based BP measurements. Disease severity, fluid intake, orthostatic and overactive bladder symptoms, falls, comorbidities and medication history were evaluated.

RESULTS

Patients' mean age was 66.1 ± 9.5years, with mean disease duration 7.8 ± 5.5years. OH frequency was 35.8 % based on the supine-to-stand test. OH in PD was significantly associated with older age, lower body mass index, longer disease duration, worse motor, cognitive and overactive bladder symptoms and functional disabilities, falls, and lower fluid intake. A similar profile was seen with asymptomatic OH. Three quarters of OH were neurogenic, with the majority also having supine hypertension. The sit-to-stand test had a sensitivity of only 0.39. One quarter of patients were additionally diagnosed with OH during continuous BP monitoring.

CONCLUSIONS

The sit-to-stand test substantially underdiagnoses OH in PD, with the important practice implication that supine-to-stand measurements may be preferred. Screening for OH is warranted even in asymptomatic patients. Adequate fluid intake, treatment of urinary dysfunction and falls prevention are important strategies in managing PD patients with OH.

Pulse transit time-estimated blood pressure: a comparison of beat-to-beat and intermittent measurement

Pulse transit time (PTT), which refers to the travel time between two arterial sites within the same cardiac cycle, has been developed as a novel cuffless form of continuous blood pressure (BP) monitoring. The aim of this study was to investigate differences in BP parameters, including BP variability, between those assessed by beat-to-beat PTT-estimated BP (eBP_BTB) and those assessed by intermittent PTT-estimated BP at fixed time intervals (eBP_INT) in patients suspected of having sleep disordered breathing (SDB). In 330 patients with SDB (average age, 66.8 ± 11.9 years; 3% oxygen desaturation index [ODI], 21.0 ± 15.0/h) from 8 institutes, PTT-estimated BP was continuously recorded during the nighttime. The average systolic eBP_BTB, maximum systolic and diastolic eBP_BTB, standard deviation (SD) of systolic and diastolic eBP_BTB, and coefficient variation (CV) of systolic and diastolic eBP_BTB were higher than the respective values of eBP_INT (all P < 0.05). Bland–Altman analysis showed a close agreement between eBP_BTB and eBP_INT in average systolic BP and SD and CV of systolic BP, while there were disagreements in both minimum and maximum values of eBP_BTB and eBP_INT in patients with high systolic BP (P < 0.05). Although systolic BP variability incrementally increased according to the tertiles of 3%ODI in both eBP_BTB and eBP_INT (all P < 0.05), there was no difference in this tendency between eBP_BTB and eBP_INT. In patients with suspected SDB, the difference between eBP_BTB and eBP_INT was minimal, and there were disagreements regarding both the minimum and maximum BP. However, there were agreements in regard to the index of BP variability between eBP_BTB and eBP_INT.

Non-invasive continuous blood pressure monitoring systems: current and proposed technology issues and challenges

High blood pressure (BP) or hypertension is the single most crucial adjustable risk factor for cardiovascular diseases (CVDs) and monitoring the arterial blood pressure (ABP) is an efficient way to detect and control the prevalence of the cardiovascular health of patients. Therefore, monitoring the regulation of BP during patients' daily life plays a critical role in the ambulatory setting and the latest mobile health technology. In recent years, many studies have been conducted to explore the feasibility and performance of such techniques in the health care system. The ultimate aim of these studies is to find and develop an alternative to conventional BP monitoring by using cuff-less, easy-to-use, fast, and cost-effective devices for controlling and lowering the physical harm of CVDs to the human body. However, most of the current studies are at the prototype phase and face a range of issues and challenges to meet clinical standards. This review focuses on the description and analysis of the latest continuous and cuff-less methods along with their key challenges and barriers. Particularly, most advanced and standard technologies including pulse transit time (PTT), ultrasound, pulse arrival time (PAT), and machine learning are investigated. The accuracy, portability, and comfort of use of these technologies, and the ability to integrate to the wearable healthcare system are discussed. Finally, the future directions for further study are suggested.