#50 The relationship between pre-dialysis plasma endothelin-1 and the intradialytic decline in blood pressure

Abstract

Abstract Background and Aims Endothelin-1 (ET-1), a potent vasoconstrictor, may play an important role in the blood pressure (BP) response to hemodialysis (HD). Patients receiving maintenance HD have higher concentrations of plasma endothelin-1 than non-HD patients with advanced chronic kidney disease or patients receiving peritoneal dialysis. We wished to examine the association between the pre-HD level of ET-1 and the magnitude of intradialytic systolic BP decline. Methods Data was collected in a prospective study of 50 patients receiving maintenance HD admitted to Brigham and Women's Hospital in Boston, MA, USA. BP was measured before and every 15 min during a single HD session using an automated BP cuff. The systolic BP decline was calculated as the pre-HD minus the lowest intradialytic systolic BP. Blood samples were collected pre-HD. Patients with missing data, HD <3 h, or pre-dialysis BP <85/55 mmHg were excluded from the analysis (n = 8). Spearman's rho (ρ) was used to assess the correlation between pre-HD ET-1 and intradialytic systolic BP decline. Results Of the 42 included patients, 17 were females, median age 62 [25th, 75th percentile: 50, 70] years. The median HD duration was 232 [210, 242] min and median ultrafiltration was 2.1 [2, 3] L. Before HD, the median ET-1 was 2.4 [1.9, 3.0] pg/mL, the median systolic BP was 141 [119, 167] mmHg, and the median diastolic BP was 68 [63, 84] mmHg. A moderate negative correlation was observed between the baseline ET-1 and the intradialytic decline in systolic BP (ρ = –0.34, P = 0.03). This correlation was stronger in patients with baseline systolic BP >120 mmHg (ρ = –0.51, P = 0.004, n = 30) and much stronger in patients with baseline systolic BP >140 mmHg (ρ = –0.66, P = 0.001, n = 21). Almost all cases (8 out of 9) with an intradialytic decline in systolic BP of >50 mmHg occurred in patients with baseline ET-1 below the pre-HD median level. Conclusions Our results suggest that hospitalized patients with pre-HD systolic BP >140 mmHg and lower baseline ET-1 may be more likely to experience larger intradialytic declines in systolic BP. Whether measurement of pre-HD ET-1 could help identify hypotensive-prone patients requires further investigation in larger studies.