In Kidney Donors, Reduced GFR Is Cardiovascular Risk Factor

The reduction in glomerular filtration rate (GFR) after living kidney donation is associated with increased left ventricular mass and other changes in cardiovascular structure and function, reports a study in Hypertension.

The study included 68 living kidney donors and 56 non-donor controls enrolled in the UK prospective Chronic Renal Impairment in Birmingham–Donor study. Potential adverse structural and functional cardiovascular effects associated with unilateral nephrectomy were assessed. The primary outcome was change in left ventricular mass from baseline to 12 months, assessed by magnetic resonance imaging.

Twelve months after nephrectomy, living kidney donation was associated with a 30 mL/min/1.73 m2 decrease in isotopic GFR. Left ventricular mass increased by 7 g in the donors, compared to a 3 g decrease in controls. Living kidney donors also had a significant increase in left ventricular mass to volume ratio, and significant decreases in aortic distensibility and global circumferential strain.

Living kidney donors were more likely to develop detectable levels of highly sensitive troponin T and microalbuminuria: odds ratio 16.2 and 3.8, respectively. There were also significant increases in serum uric acid, parathyroid hormone, fibroblast growth factor-23, and high-sensitivity C-reactive protein, but no change in ambulatory blood pressure. The increase in left ventricular mass was independently related to the decrease in isotopic GFR.

Living kidney donation is associated with a lasting reduction in GFR; the long-term effects on cardiovascular risk are unclear. The new study provides evidence of adverse left ventricular remodeling in donors with reduced renal function after unilateral nephrectomy. Reduced kidney function “should be regarded as an independent causative cardiovascular risk factor,” the investigators conclude [Moody WE, et al. Cardiovascular effects of unilateral nephrectomy in living kidney donors. Hypertension 2016; 67: 368–377].