Changes in Blood Pressure and Arterial Hemodynamics following Living Kidney Donation

Abstract

Background and objectives: The Effect of a Reduction in GFR after Nephrectomy on Arterial Stiffness and Central Hemodynamics (EARNEST) study was a multicenter, prospective, controlled study designed to investigate the associations of an isolated reduction in kidney function on BP and arterial hemodynamics.

Design, setting, participants, & measurements: Prospective living kidney donors and healthy controls who fulfilled criteria for donation were recruited from centers with expertise in vascular research. Participants underwent office and ambulatory BP measurement, assessment of arterial stiffness, and biochemical tests at baseline and 12 months.

Results: A total of 469 participants were recruited, and 306 (168 donors and 138 controls) were followed up at 12 months. In the donor group, mean eGFR was 27 ml/min per 1.73 m2 lower than baseline at 12 months. Compared with baseline, at 12 months the mean within-group difference in ambulatory day systolic BP in donors was 0.1 mm Hg (95% confidence interval, -1.7 to 1.9) and 0.6 mm Hg (95% confidence interval, -0.7 to 2.0) in controls. The between-group difference was -0.5 mm Hg (95% confidence interval, -2.8 to 1.7; P=0.62). The mean within-group difference in pulse wave velocity in donors was 0.3 m/s (95% confidence interval, 0.1 to 0.4) and 0.2 m/s (95% confidence interval, -0.0 to 0.4) in controls. The between-group difference was 0.1 m/s (95% confidence interval, -0.2 to 0.3; P=0.49).

Conclusions: Changes in ambulatory peripheral BP and pulse wave velocity in kidney donors at 12 months after nephrectomy were small and not different from controls.

Clinical trial registry name and registration number: NCT01769924 (https://ichgcp.net/clinical-trials-registry/NCT01769924).

Keywords: arterial stiffness; arteries; blood pressure; chronic kidney disease; hemodynamics; hypertension; living kidney donors; pulse wave velocity.

Copyright © 2020 by the American Society of Nephrology.

Figures

Graphical abstract

Figure 1.

A typical example of an aortic pulse pressure waveform. The maximum pressure is systolic and the minimum pressure is diastolic. The first peak, the forward wave, indicates ejected blood from the heart. The second peak, the reflected wave, is that returned from peripheral vasculature. The difference between the two is augmentation pressure. Augmentation index is augmentation pressure expressed as a percentage of pulse pressure (43). Because augmentation index is influenced by timing of the reflected wave, augmentation index is corrected for a heart rate of 75 beats per minute (43). Reprinted from ref. 43, which is available under the terms of the Creative Commons Attribution License.

Figure 2.

Participants recruited into the EARNEST study. *Following eligibility assessment, there were 22 patients who consented to take part but were ultimately excluded from the study. After baseline blood tests, two “healthy controls” did not meet criteria due to incidental findings: one was diagnosed with diabetes and one had an insufficient kidney function. Consequently, neither met living kidney donation criteria. A further 20 patients consented to take part and withdrew before completing baseline assessment. This was usually because of competing appointments during living kidney donor workup.