Effect of reduced sympathetic hyperactivity on cardiovascular risk factors in kidney transplantation patients

Abstract

Background: Hyperactivity of the sympathetic nervous system caused by chronic kidney disease has detrimental effects on hypertension and cardiovascular morbidity. Kidney transplantation does not ameliorate sympathetic nerve overactivity; however, bilateral nephrectomy eliminates it. The aim of the study was to evaluate the effect of bilateral nephrectomy on risk factors for cardiovascular morbidity and mortality in long-term follow-up.

Material and methods: We studied 24 kidney recipients aged 44 ± 13 years who had undergone native bilateral nephrectomy. The control group included 17 recipients with preserved native kidneys who were matched for age, gender, cause of end-stage renal disease, immunosuppressive treatment, and time after transplantation. The mean follow-up after transplantation was 103 months. We evaluated arterial blood pressure, pulse pressure, metabolic markers, allograft function, echocardiography, and cardiac morbidity in all patients throughout follow-up.

Results: Systolic and diastolic blood pressures, number of antihypertensive drugs, and pulse pressure (a marker of arterial stiffness), were significantly lower among the study versus the control group (P < .05). The left ventricular mass, left ventricular mass index, left ventricular posterior wall thickness, and interventricular septum thickness were also lower in the study than in the control group (P < .05). Cardiac morbidity, including ischemic heart disease, atrial fibrillation, heart failure and stroke, occurred in 4 (16%) study group and 6 (35%) control subjects. Metabolic disorders, namely, new onset diabetes after transplantation, hyperuricemia, and dyslipidemia, occurred with similar frequencies in both groups. Serum levels of creatinine and estimated glomerular filtration rates were comparable in both groups, remaining stable throughout the observation time.

Conclusions: Reduction of sympathetic hyperactivity by nephrectomy improved blood pressure control as well as decreased arterial stiffness and left ventricular hypertrophy over long-term follow-up. These results support native renal denervation to prevent the harmful effects of sympathetic hyperactivity on the cardiovascular system of renal transplant recipients.