Risk Evaluation of Immediate Surgical Failure During Thigh Hemodialysis Graft Placement by Sonographic Screening

Imaging Patients with Kidney Failure

The approach to imaging a patient with kidney failure continues to evolve. Overstatement of the risk of iodinated contrast material-induced (ie, contrast-induced) acute kidney injury and new guidelines for administration of gadolinium-based contrast media affect screening and the choice of contrast material. Treatment of kidney failure requires dialysis or a kidney transplant. Pretransplant imaging includes assessment for the feasibility of performing a transplant and evaluation for underlying malignancy and peripheral vascular disease. Patients with kidney failure are at high risk for renal cell carcinoma. Subtypes that occur exclusively or more commonly in patients with kidney failure, such as acquired cystic kidney disease, renal cell carcinoma, and clear cell papillary renal cell carcinoma, have specific clinical-pathologic characteristics, with indolent behavior. Performing US for dialysis planning increases the success of placement of an arteriovenous fistula, while postoperative US evaluation is essential in assessment of access dysfunction. Systemic manifestations in patients with kidney failure are multifactorial and may relate to the underlying cause of renal failure or may be secondary to treatment effects. Disturbances in mineral and bone metabolism and soft-tissue and vascular calcifications are seen in patients with chronic kidney disease and mineral bone disorder. Neurologic and cardiothoracic complications are also common. The authors provide a comprehensive overview of imaging considerations for patients with kidney failure, including the appropriate use of CT, MRI, and US with their respective contrast agents; the use of imaging in transplant workup and dialysis assessment; and the common renal and extrarenal manifestations of kidney failure. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

New Insights into Dialysis Vascular Access: Impact of Preexisting Arterial and Venous Pathology on AVF and AVG Outcomes

Despite significant improvements in preoperative patient evaluation and surgical planning, vascular access failure in patients on hemodialysis remains a frequent and often unforeseeable complication. Our inability to prevent this complication is, in part, because of an incomplete understanding of how preexisting venous and arterial conditions influence the function of newly created arteriovenous fistulas and grafts. This article reviews the relationship between three preexisting vascular pathologies associated with CKD (intimal hyperplasia, vascular calcification, and medial fibrosis) and hemodialysis access outcomes. The published literature indicates that the pathogenesis of vascular access failure is multifactorial and not determined by any of these pathologies individually. Keeping this observation in mind should help focus our research on the true causes responsible for vascular access failure and the much needed therapies to prevent it.

We Underutilize the Leg Graft

Once hemodialysis patients have exhausted all option for a permanent vascular access in both upper extremities, they are often relegated at many dialysis centers to permanent catheter dependence with all its attendant complications, including infections, frequent dysfunction, and central vein stenosis. This commentary makes the case that thigh grafts are a far superior alternative to dialysis catheters in many of these patients. Technical graft failure may occur in some patients due to severe femoral artery calcification, but screening for calcification by ultrasound or computerized tomography can reduce the likelihood of a technical failure. Placement of a thigh graft may lead to critical lower extremity ischemia, but preoperative screening for peripheral vascular disease should minimize this possibility. Thigh grafts have comparable secondary patency to that obtained with upper extremity grafts. Finally, although the risk of infection is somewhat higher for thigh grafts than upper extremity grafts, it is still much lower than the risk of catheter-related bacteremia. In summary, thigh grafts should be used much more frequently in patients without an option for an upper extremity access.