Neurogenic Supine Hypertension and Cardiovascular Autonomic Dysfunction in Patients with Parkinson's Disease

Natural history and disease progression in patients with Idiopathic Parkinson's Disease (PD) is quite heterogeneous. Autonomic dysfunction occurs commonly among Idiopathic PD patients. Heart rate variability and ambulatory blood pressure monitoring are used to assess cardiac autonomic dysfunction. The prevalence and magnitude of supine hypertension in Indian PD patients has not been studied to date. The present study aimed to record cardiovascular autonomic functions and supine hypertension in PD patients and to correlate them with the age of onset, duration and severity of the disease, and non-motor symptom burden.

The cross-sectional study involved 60 PD patients. Webster rating scale was used to determine the disease severity. Non-motor symptom burden was assessed using the Non-Motor Symptom Scale (NMSS). Ambulatory blood pressure monitoring and heart rate variability parameters determined cardiac autonomic function. Supine hypertension was defined as Systolic Blood Pressure (SBP) ≥150 mmHg and/or DBP ≥90 mmHg. Less than 10% decrease or even increase in blood pressure during the night were classified as non-dippers. Pearson coefficient was used appropriately to establish correlation. P ≤ 0.05 was considered significant.

Age of onset was 61.2 ± 8.7 years and duration of disease was 1.7 ± 1.1 years. Mean Webster and non-motor symptom scores were 12.7 ± 4.4 and 15.5 ± 8.0, respectively. About 50 patients (83%) were non-dipper, while 32 (53%) had supine hypertension. Low Frequency oscillations (LF) (r = 0.28), High Frequency oscillations (HF) (r = 0.29), Standard Deviation NN intervals (SDNN) (0.26), and Root Mean Squared Successive Differences of NN intervals (RMSSD) (r = 0.28) correlated significantly with non-motor symptoms scale. LF (r = -0.39), HF (r = -0.43), SDNN (-0.40), RMSSD (r = -0.41), NN50 (r = -0.38), PNN50 (r = -0.42), mean SBP (r = 0.26), and mean DBP (r = 0.33) correlated significantly with disease duration. PNN50 (r = -0.255), mean SBP (r = -0.29), and mean DBP (r = -0.27) correlated significantly with age at onset.

Awareness regarding neurogenic supine hypertension is needed as it occurs commonly among Indian PD patients. Heart rate variability (HRV) parameters and ambulatory blood pressure are of significant help in the detection of early cardiovascular autonomic dysfunction and correlate significantly with disease duration and non-motor symptom burden among PD patients.