Cardiac Tissue Sodium Assessment in CKD Patients Using Sodium MRI

Chronic kidney disease (CKD) is prevalent worldwide and affects around 10% of people living in developed health economies. As the kidney loses its function in patients with CKD, the kidneys are unable to filter toxins out of the blood as efficiently as those of healthy individuals. Arguably, sodium (salt) is the most relevant toxin in CKD and can build up in the kidneys of patients with CKD. Salt build-up has also been found to occur in the heart muscle tissue and could drive the development of scarring of the heart muscle tissue which contributes to heart failure.

Using sodium magnetic resonance imaging (MRI), we would like to measure the levels of salt in the heart muscle tissue. We will examine whether the heart muscle tissue has high salt levels, and if so, whether this relates to any heart defects. A conventional proton MRI will be done to measure heart function. The MRI images of healthy volunteers, CKD patients, and those on hemodialysis will be analyzed for levels of salt and the findings will then be compared to the cardiac biomarkers (proteins or enzymes that are released into the blood when the heart is damaged or stressed) and fibrosis (scarring) measured from each patient's proton MRI images to establish a possible correlation. This research has the potential to precede additional studies that may investigate the effect of diuretics (a drug that increases the production of urine) on the heart muscle tissue of CKD patients.

Using sodium magnetic resonance imaging (MRI), it is possible to measure the sodium content in the cardiac tissue of patients with kidney disease. In this research study, it will be investigated whether the elevated levels of sodium in patients with kidney disease is also present in their hearts, and if so, whether this relates to cardiac abnormalities. Cardiac sodium MRI images of healthy volunteers, hemodialysis patients, and CKD patients will be analyzed for sodium content. This sodium information will then be compared to the biomarkers of cardiac function and fibrosis measured from each patient's proton MRI images in order to establish a possible correlation. This research has the potential to precede additional studies that may investigate the effect of diuretics on the cardiac tissue of kidney disease patients.

This study is a pilot exploratory study (preliminary project to assess the use of a heart sodium coil across a wide spectrum of kidney disease). We will recruit up to 150 participants: approximately 50 hemodialysis patients, 50 patients with various stages of chronic kidney disease, and 50 age and sex matched healthy participants to compare clinical characteristics to. This study involves one study visit at the Robarts Research Institute, London, Ontario lasting approximately 3 hours.

This study entails one visit where all participants will undergo a proton and sodium MRI scan of the heart. Prior to the scan, all participants will have their sitting blood pressure and heart rate measured three times consecutively using a standard automatic blood pressure monitor. In addition to this, all patient participants will have blood work collected, provide a spot urine sample, complete a salt intake questionnaire, and have their fluid volume measured using bioimpedance spectroscopy. Only those patients on hemodialysis will answer a single Time to Recovery Question in addition to the above.

Eligibility Criteria:
Inclusion Criteria:

* Age greater than or equal to 18 years
* For patients on maintenance hemodialysis: more than 3 months duration of therapy
* For patients with CKD: evidence of kidney disease persisting \> 3 months and no indications to start dialysis
* For healthy controls: lack of kidney disease, cardiovascular disease, diabetes, liver cirrhosis and peripheral edema

Exclusion Criteria:

* Pregnant, breastfeeding or intending pregnancy
* Contraindication to MRI scan

  * Inability to tolerate MRI due to patient size and/or known history of claustrophobia.
  * Mechanically implanted, electrically, or magnetically activated device or any metal in their body which cannot be removed, including but not limited to pacemakers, neurostimulators, biostimulators, implanted insulin pumps, aneurysm clips, bioprosthesis, artificial limb, metallic fragment or foreign body, tattoos, shunt, surgical staples (including clips or metallic sutures and/or ear implants.)