Login to Access Video or Poster Abstract: MP74-17
Sources of Funding: None

Introduction

Donor kidney volume (KV) is an increasingly important parameter evaluated before living kidney donation. It potentially enhances the estimation of glomerular filtration rate before surgery, measures split renal function for selection of the explantation side and prognosticates recipient function following transplantation. However, KV measurements on Computerised Tomographic (CT) scanning requires a manually intensive process of manual or semi-automatic segmentation of kidneys with inter-observer variation. Renal artery diameter (RAD) is an easier marker to measure and this study aims to investigate the relationship between donor RAD and KV.

Methods

A retrospective review of consecutive patients who underwent living donor nephrectomy between 2010 and 2016 was conducted. In all patients, bilateral kidney volumes were measured based on contrast-enhanced CT scan imaging, using segmentation of functional nephron mass to exclude sinus fat, blood vessels and the pelvi-calyceal system. For the renal artery maximum diameter, we measured the RAD at the vessel cross section just distal to the aortic ostia. Measurements were taken between the tunica intima by direct visualisation on the arterial phase of transverse CT slices. Estimated Glomerular Filtration Rate (eGFR) was determined using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation from serum creatinine levels collected before surgery.

Results

92 consecutive living donor nephrectomy patients were reviewed. After excluding 15 patients with multiple arteries, 77 patients (55.8% Female, 58.4% Chinese) were available for this study. The mean age of the donors was 44.4+/-12.7 years. Controlled hypertension, hyperlipidemia and smoking were present in 9(11.7%), 17 (22.1%) and 7 (9.2%) patients with no other significant co-morbidities. All patients had normal blood pressure (BP) measurements pre-operatively with a mean systolic and diastolic BP of 122.4+/-14.4 and 72.4+/-10.4 mmHg respectively. Mean right and left KVs were 132.8+/-25.9 and 138.9+/-24.8 cm3 respectively. Mean right and left RADs were 4.86+/-0.91 and 5.14+/-0.85 mm respectively On regression analysis, there was a significant association between the right and left RADs and their ipsilateral KVs with a regression coefficient of 7.9 (95% C.I. 1.3-14.5, P=0.019) and 9.8 (95% C.I. 3.3-16.3, P=0.004) respectively. Mean eGFR pre-operatively was 105.1+/-14.9 mL/min/1.73 m2. Mean total RAD (the sum of both left and right RAD) was 9.61+/-2.51mm. It was found to be correlated with pre-operative eGFR at 0.095. Patients with pre-operative eGFR of < 100 mL/min/1.73 m2 had a lower total RAD than those with eGFR>100 mL/min/1.73 m2 (9.38+/-3.44 mm vs 9.73+/-1.86 mm, p=n.s.)

Conclusions

This study demonstrates that renal artery size is positively associated with kidney volume and may be used as a more easily measured surrogate marker for kidney size with its attended implications in living donor transplantation.

Funding

None