A Study of Novel Biomarkers of Kidney Dysfunction at Liver Transplant

Summary

Kidney dysfunction before and immediately after liver transplantation is common and leads to poorer outcomes, including prolonged need for post-operative intensive care, diminished graft survival, and greater risk of permanent kidney dysfunction and death. Blood creatinine level - the standard measure of kidney function - is suboptimal in people with advanced liver disease, overestimating kidney function by \>20%. There is significant concern that liver transplant recipients are at higher risk of acute kidney injury (AKI) than we can currently predict. This study aims to identify superior tests (blood/urine or imaging) for kidney dysfunction, to enable improved treatment and patient outcomes.

This study aims to recruit 80-100 consecutive patients admitted to the Scottish Liver Transplant Unit (SLTU), Royal Infirmary of Edinburgh (RIE) for liver transplant assessment over a 6 month period. Permission will be sought to record the results of routine tests performed by the NHS during this assessment week. These tests include: electrocardiograph (ECG), Computed Tomography (CT) liver and abdomen, cardio-pulmonary exercise testing (CPEX), pulmonary function tests (PFTS), routine haematology and biochemistry blood tests, 24 hour urine collection and body composition analysis.

In addition, we will invite participants to attend the RIE clinical research facility (CRF) for a single visit (\~2 hours) to perform extra research assessments. Blood and urine will be collected for biomarker analysis. Non-invasive assessment of cardiovascular function will be completed using cardiac bio-impedance and aortic pulse wave velocity. Examination of the blood vessels at the back of the eye will be performed using optical coherence tomography.

A subgroup of 10 participants will undergo magnetic resonance imaging (MRI) of the kidneys using arterial spin labelling to identify dysregulated renal perfusion. Patients who are transplanted during the study timeframe will be asked to re-attend the CRF for repeat assessments at 6 weeks post transplantation.

Funded by Scottish Liver Transplant Unit Endowment Fund

Conditions

• Liver Transplantation
• Liver Transplant; Complications
• Kidney Dysfunction

Interventions

DIAGNOSTIC_TEST

Blood sample for serum and plasma biomarkers:

Serum/plasma biomarkers: Approximately 10ml (3 teaspoons) of blood will be extracted to measure pre-specified biomarkers of renal injury including kidney injury molecule-1 (KIM-1), cystatin C and neutrophil gelatinase-associated lipocalin (NGAL). Samples will then be stored to facilitate measurement of additional biomarkers in the future.

DIAGNOSTIC_TEST

Urine sample for biomarkers

Urinary biomarkers: A random urine sample will be obtained to measure urinary protein to creatinine ratio (uPCR), KIM-1 and liver-type fatty acid binding protein (L-FABP)

DIAGNOSTIC_TEST

Cardiac bio-impedance (Cardioscreen Medis)

Cardiac bio-impedance - a non-invasive assessment of cardiac output, cardiac index and systemic vascular resistance index using the bio-impedence technique (Cardioscreen 1000 Medis) Cardiac bio-impedance is performed by attaching sticky electrodes to the participant's neck and thorax. These electrodes pass a very low, constant and alternating current (1.5 mA, 86 kHz) across the thorax, which is imperceptible to the patient. This provides beat by beat data on cardiac output and haemodynamic measurements.

DIAGNOSTIC_TEST

Aortic pulse wave velocity (APWV) (TensioMed and SphygmoCor)

Aortic pulse wave velocity (APWV) a non-invasive measure of arterial function using oscillometric recordings to detail peripheral and central haemodynamics. This will be measured using two different techniques: TensioMed Arteriograph: After a rest period a blood pressure cuff inflates and deflates twice on the arm. This takes \~3 minutes and should cause only mild, temporary discomfort. The test will routinely be performed in duplicate to ensure accuracy of results. SphygmoCor: A pressure sensor is held over the radial pulse at the wrist to analyse the pulse wave. Then held over the carotid artery and/or femoral artery to assess the speed of the pulse wave through the body. The probe is similar to an ultrasound probe and should not cause any discomfort.

DIAGNOSTIC_TEST

Optical Coherence Tomography (Spectralis OCT)

OCT is a non-invasive imaging test which uses light waves to take cross sectional images of the back of the eye. Examination of the retinal and retinal nerve fibre layer thickness, macular volume, and choroidal thickness provides an assessment of generalised systemic microvascular injury. A strong correlation between choroidal thickness and renal dysfunction has previously been shown in patients with chronic kidney disease (Balmforth C et al, JCI Insight 2016). The participant is asked to sit in front of the OCT machine and rest their chin on a support to keep it motionless. The equipment will then scan the eye without touching it. Scanning takes about 5 - 10 minutes.

DIAGNOSTIC_TEST

Arterial Spin Labelling Magnetic Resonance Imaging

Magnetic resonance imaging using arterial spin labelling (ASL-MRI) This promising quantitative technique has the potential to identify dysregulated renal perfusion, stratify risk of AKI in pre-OLT patients, and to monitor alterations in renal haemodynamics in the post transplantation setting. * We aim to recruit 5 participants with 'normal' renal function (eGFR≥60ml/min/1.73m2) and a further 5 participants with 'abnormal' renal function (eGFR\<60ml/min/1.73m2) * ASL-MRI will be performed in this subgroup during the week of OLT assessment and then repeated at 6-weeks post transplantation in those participants who undergo OLT during the study period.

Sponsors & Collaborators

• NHS Lothian

  collaborator OTHER_GOV

• University of Edinburgh

  lead OTHER

Principal Investigators

• Jonathan A Fallowfield, PhD · University of Edinburgh, NHS Lothian

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2018-01-15

Primary Completion

2018-08-03

Completion

2018-09-10

Countries

• United Kingdom

Study Locations