• Myocardial blood flow [ Time Frame: One baseline visit ]
  Ultrasound measurement of myocardial blood flow using myocardial contrast echocardiography. Data will be presented as dB/sec
• Left ventricular ejection fraction [ Time Frame: One baseline visit ]
  Echocardiogram assessed left ventricular ejection fraction by Simpson's biplane method. Data will be presented as %.

• Pulse wave analysis [ Time Frame: One baseline visit ]
  Augmentation index measured using the Sphygmocor device. Data will be presented as %.
• Pulse wave velocity [ Time Frame: One baseline visit ]
  Pulse wave velocity measured using the Sphygmocor device. Data will be presented as m/s

The clinical syndrome of uraemic cardiomyopathy is prevalent in end stage renal disease and is associated with pathological cardiovascular changes including left ventricular hypertrophy, diastolic dysfunction and diffuse interstitial fibrosis. These combine to confer an elevated cardiovascular risk, including an increased risk of sudden cardiac death.

The cause of this increased cardiovascular risk is not clear but it is thought that coronary microvascular dysfunction may play a role. Coronary microvascular dysfunction is prevalent in many myocardial disease states, such as hypertrophic cardiomyopathy and heart failure with preserved ejection fraction, that share pathological similarities with uraemic cardiomyopathy.

Coronary flow reserve, a marker of coronary microvascular function, can be assessed non-invasively using echocardiography techniques. Previous studies have shown a reduction in coronary flow reserve in patients with chronic kidney disease. However, it is not clear if kidney donors - individuals who have a reduced kidney function but do not have progressive kidney disease - also demonstrate microvascular dysfunction. Similarly, although there is some evidence that patients on dialysis have improved coronary flow reserve compared to patients with pre-dialysis chronic kidney disease stage 5, there has been limited investigation into the role of peritoneal dialysis on coronary flow reserve.

• Kidney Disease, Chronic
• Myocardial Dysfunction

• Diagnostic Test: Coronary flow reserve assessment
  Coronary flow reserve will be assessed using Doppler transthoracic echocardiograpy and myocardial contrast echocardiography.
• Diagnostic Test: Sphygmocor
  Pulse wave analysis and pulse wave velocity will be assessed using the Sphygmocor device
• Diagnostic Test: Electrocardiogram
  An electrocardiogram will be performed prior to administration of adenosine to ensure no resting conduction disease
• Other: Blood test
  Blood tests will be performed for markers of renal function, bone mineral metabolism and myocardial stretch and injury
• Other: Urinary albumin/creatinine ratio
  Urine will be analysed for albumin/creatinine ratio

• Controls
  25 controls with preserved renal function
  Interventions:

  • Diagnostic Test: Coronary flow reserve assessment
  • Diagnostic Test: Sphygmocor
  • Diagnostic Test: Electrocardiogram
  • Other: Blood test
  • Other: Urinary albumin/creatinine ratio
• Kidney Donors
  25 living kidney donors who have donated a kidney at least 12 months prior to enrollment in the study.
  Interventions:

  • Diagnostic Test: Coronary flow reserve assessment
  • Diagnostic Test: Sphygmocor
  • Diagnostic Test: Electrocardiogram
  • Other: Blood test
  • Other: Urinary albumin/creatinine ratio
• Pre-dialysis
  25 patients with pre-dialysis chronic kidney disease stage 5
  Interventions:

  • Diagnostic Test: Coronary flow reserve assessment
  • Diagnostic Test: Sphygmocor
  • Diagnostic Test: Electrocardiogram
  • Other: Blood test
  • Other: Urinary albumin/creatinine ratio
• Peritoneal dialysis
  25 patients with chronic kidney disease stage 5 undergoing peritoneal dialysis
  Interventions:

  • Diagnostic Test: Coronary flow reserve assessment
  • Diagnostic Test: Sphygmocor
  • Diagnostic Test: Electrocardiogram
  • Other: Blood test
  • Other: Urinary albumin/creatinine ratio

Inclusion Criteria:

• Healthy control with normal renal function
• Living kidney donor who has donated >12 months prior to enrolment in study
• Chronic kidney disease stage 5 who are pre-dialysis or on peritoneal dialysis
• Able to provide written informed consent

Exclusion Criteria:

• Pregnancy
• Known ischaemic heart disease
• Diabetes mellitus
• Uncontrolled hypertension
• Evidence of 2nd or 3rd degree AV block or sick sinus syndrome in absence of a pacemaker
• History of allergic/adverse reaction to adenosine or Sonovue
• History of long QT syndrome
• Severe hypotension
• Significant valvular heart disease
• Significant chronic obstructive pulmonary disease or asthma with bronchospasm
• Unstable angina not controlled with medication
• Concurrent use of dipyridamole
• Decompensated heart failure
• Poor echo acoustic windows
• Chronic kidney disease stage 5 on haemodialysis