Early Sympathetic Activation in the Initial Clinical Stages of Chronic Renal Failure

Direct and indirect indices of neuroadrenergic function have shown that end-stage renal disease is characterized by a marked sympathetic overdrive. It is unknown, however, whether this phenomenon represents a peculiar feature of end-stage renal disease or whether it is also detectable in the early clinical phases of the disease. The study has been performed in 73 hypertensive patients, of which there were 42 (age60.7±1.8 years, mean±SEM) with a stable moderate chronic renal failure (mean estimated glomerular filtration rate40.7 mL/min per 1.73 m, MDRD formula) and 31 age-matched controls with a preserved renal function. Measurements included anthropometric variables, sphygmomanometric and beat-to-beat blood pressure, heart rate (ECG), venous plasma norepinephrine (high-performance liquid chromatography), and efferent postganglionic muscle sympathetic nerve activity (microneurography, peroneal nerve). For similar anthropometric and hemodynamic values, renal failure patients displayed muscle sympathetic nerve activity values significantly and markedly greater than controls (60.0±2.1 versus 45.7±2.0 bursts per 100 heartbeats; P