Spectrum of Cardiovascular Autonomic Dysfunction and 24-hour Blood Pressure Variability in Idiopathic Parkinson's Disease

Uncertainty prevails regarding the patterns of autonomic dysfunction in patients with idiopathic Parkinson's disease (IPD). This study was undertaken with the aim of assessing the complete spectrum of cardiovascular autonomic function tests (CAFTs) and blood pressure variability patterns in IPD patients while comparing the same with age-matched controls.

Patients with IPD presenting to the Christian Medical College and Hospital from December 2016 to November 2018 along with age-matched controls were prospectively evaluated using CAFTs. The IPD patients also underwent ambulatory blood pressure (BP) monitoring (ABPM), and the diurnal systolic BP differences were used to classify into dippers (10-20%), non-dippers (0-10%), reverse dippers (<0%), and extreme dippers (>20%).

Autonomic dysfunction (AD) was prevalent in 41 (68.3%) IPD patients even in early disease (median (inter-quartile range) symptom duration 2 (1-4) years, mean Hoehn and Yahr (H&Y) stage 2 (1.5-2.8). Both sympathetic and parasympathetic parameters were impaired among IPD patients when compared to healthy controls. (E: I ratio 1.17 ± 0.12 vs 1.26 ± 0.14 (P < 0.001), Valsalva ratio (VR) 1.33 ± 0.27 vs 1.55 ± 0.25 (P < 0.001), PRT₁₀₀ 9.6 ± 8.0 vs 3.1 ± 1.8 (P < 0.001), tilt-up SBP_Avg change 8.8 (4.2-13.8) vs 1.8 (-2.9-6.1) (P < 0.001), tilt-up HR_Avg change 4.8 (2.2-8.2) vs 1.9 (-0.7-5.1) (P < 0.001). BP variability was demonstrated in 47 (79.7%) of IPD patients, with reverse dipping pattern in 28 (47.5%) seen more frequently in this cohort.

Timely detection of AD may be helpful not only in recognizing IPD in its pre-motor stages but also in optimizing management for this population of patients. BP variability and abnormal dipping patterns on ABPM can be a potential marker of dysautonomia.