Vascular Grafting clinical trials

Ferumoxytol Enhanced Magnetic Resonance Angiography in Chronic Kidney Disease

Conventional vascular imaging techniques are often either contra-indicated in chronic kidney disease (CKD) patients due to their relative invasiveness, risks and cost. Computed tomography angiography (CTA) requires radiation and nephrotoxic iodinated contrast which may precipitate significant worsening of renal function and even prompt the need for institution of dialysis. Magnetic resonance angiography (MRA) using gadolinium-based contrast agents has been associated with the rare disease nephrogenic systemic fibrosis. Alternative imaging methods also have drawbacks: for example, this frail patient group has a higher risk of complications from conventional invasive catheter-based angiography, non-contrast-enhanced MRA allows visualization of smaller arteries but is less accurate for larger vascular structures, and ultrasound is often not appropriate for evaluation of the deep vessels of the abdomen and pelvis. Ferumoxytol is an ultrasmall superparamagnetic iron oxide particle encapsulated by a semisynthetic carbohydrate, which was initially developed as a magnetic resonance imaging (MRI) contrast agent in 2000. However, interest in ferumoxytol as a therapeutic agent for the treatment of iron deficiency anaemia in the setting of CKD eclipsed its use as MRI contrast agent. During the last decade, ferumoxytol has gained appeal as an MRI contrast agent in patients with estimated glomerular filtration rates <30mL/min and there are reports in the literature for its safe use and utility in both adult and pediatric patients with CKD. Participants will be selected from those who have been referred for assessment prior to kidney transplant or prior to vascular access creation for haemodialysis and will be divided into three groups. The first group will include patients who will undergo a CTA of abdominal and aortoiliac vasculature as part of their preparation for potential kidney transplantation. The second and third groups will include patients who are having a fistula or a graft created for dialysis, respectively. These patients are routinely having US vascular mapping to visualise the blood vessels before a fistula or a graft is created. Additionally, patients included in the second and third groups are routinely having surveillance scans of their fistula or graft at 6 weeks following creation. Study participants undergoing standard imaging tests as part of their clinical care will also have ferumoxytol-enhanced MRA (FeMRA).