Attenuated Cardiovascular Response to Sympathetic System Activation during Exercise in Patients with Dialysis-Induced Hypotension

Abstract

Background: We wished to investigate potential causes of dialysis-induced hypotension (DIH), including the attenuated cardiovascular response to sympathetic system activation during exercise and myocardial dysfunction. Methods: This study included 26 end-stage renal disease (ESRD) patients with DIH, 30 ESRD patients without DIH (Non-DIH), and 30 control subjects. Each patient was evaluated with echocardiography and a symptom-limited treadmill stress test. The chronotropic index (CRI), heart rate recovery (HRR), systolic blood pressure response to exercise (SBP response), and tissue Doppler systolic myocardial velocities were calculated. Results: The HRR and velocities were reduced in dialysis patients compared to controls; however, they were similar in patients with and without DIH. Patients with DIH had the lowest CRI compared to theNon-DIH group (0.62 ± 0.15 vs. 0.73 ± 0.17, p = 0.020) and controls (0.62 ± 0.15 vs. 0.86 ± 0.11, p < 0.001). Similarly, patients with DIH had the lowest SBP response values compared to the Non-DIH (34.88 ± 15.01 vs. 55.67 ± 25.42, p = 0.002) and controls (34.88 ± 15.01 vs. 59.70 ± 23.04, p < 0.001). Conclusion: Patients with DIH have inadequate sympathetic activity of the cardiovascular system during exercise and impaired left ventricular systolic function. Both factors could contribute to the development of hypotension during hemodialysis.