Altered Autonomic Reactivity During Lower Body Negative Pressure in End-Stage Renal Disease

• Authors: Kara Ye, Emory University; Ida Fonkoue, Emory University; Yunxiao Li, Emory University; Dana R. DaCosta, Emory University; Amit Shah, Emory University; Jeanie Park, Emory University
• Journal Title: American Journal of the Medical Sciences
• Volume: Volume 358, Number 1
• Publisher: Elsevier Science Inc. | 2019-07-01, Pages 11-18
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.amjms.2019.04.003
• Subjects: Health Sciences, Medicine and Surgery; Health Sciences, Health Care Management; Biology, Bioinformatics; Biology, Biostatistics
• Keywords: Science & Technology; Life Sciences & Biomedicine; Medicine, General & Internal; General & Internal Medicine; Heart rate variability; Sympathetic activity; Parasympathetic activity; Autonomic function; Blood pressure variability; End-stage renal disease (ESRD); Heart rate variability; Power spectrum analysis; Blood pressure; Baroflex; Hypertensive patients; Cardiovascular patients; Dysfunction; Baroceptor; Hypotension; Amlopidine

Abstract

Background: End stage renal disease (ESRD) is characterized by autonomic dysfunction. During orthostatic stress, sympathetic (SNS) activity increases and parasympathetic (PNS) activity decreases to maintain arterial blood pressure (BP). We hypothesized that ESRD patients have impaired ability to adjust cardiac SNS and PNS activity during orthostasis, which could contribute to increased blood pressure variability, orthostatic intolerance and falls. Methods: We measured beat-to-beat BP and Electrocardiography at baseline and during increasing lower body negative pressure (LBNP) in 20 ESRD patients and 18 matched controls (CON). Heart rate variability was quantified as total power (TP) and standard deviation of the N-N interval, reflecting both SNS and PNS; high frequency (HF), root mean square of successive differences of neighboring N-N intervals (RMSSD), and percent of consecutive N-N intervals differing >50 milliseconds (pNN50), reflecting cardiac PNS activity; and low frequency (LF) and LF/HF, reflecting sympoathovagal balance. BP variability was quantified as the standard deviation in systolic (SDSAP) and diastolic (SDDAP) BP. Results: Baseline HF, RMSSD, and pNN50 were significantly lower in ESRD (P < 0.05). While CON had a significant decrease in HF (P = 0.015), RMSSD (P = 0.003), and pNN50 (P = 0.005) during LBNP, there was no change in heart rate variability in ESRD. There was no significant difference in BP response, but ESRD had a significantly blunted heart rate response during graded LBNP compared to controls (P < 0.001). There was no significant difference in SDSAP or SDDAP during LBNP between groups (P > 0.05). Conclusions: These data suggest that ESRD patients have impaired autonomic adjustments to orthostatic stress.