Resistance index measured by Doppler ultrasound as a predictor of graft function after kidney transplantation.

INTRODUCTION: Doppler ultrasound (US) has become the primary imaging technique for the evaluation of renal transplants. It provides information about the intrarenal resistance index (RI). A high RI is seen in every form of graft dysfunction. In this article, we review the utility of sonography, particularly the intrarenal RI measured early after renal transplant, as a predictor of acute and chronic clinical outcome in patients. RESULTS: RI is a valuable marker to determine graft function and related vascular complications. It reveals a strong correlation with serum creatinine levels measured days after transplant. Its elevation is typical for acute tubular necrosis and can be used to predict its duration. An RI >1 (absent end-diastolic flow) seen in the first weeks after transplant is associated with impaired renal graft recovery. In addition, it is an early predictor of chronic allograft nephropathy (even correlated with biopsy results), which will allow a change in therapy. CONCLUSIONS: RI measured serially in the early period after kidney transplantation is a valuable marker for determining renal graft function. It is also useful for demonstrating various types of graft dysfunction; however, it cannot differentiate between them. In recent studies, extrarenal factors in kidney transplantation (eg, recipient's age) may significantly influence RI in the recipient, demonstrating that RI depends on the vascular characteristics of the recipient and not on the graft itself.

Urinary tract infection and kidney transplantation: a review of diagnosis, causes, and current clinical approach.

Urinary tract infection (UTI), including bacteriuria, cystitis, and pyelonephritis, is the most common infectious complication after kidney transplantation (KTx). Over the past few years, many medical groups assumed this pathological process to be a "benign" disease in kidney transplant recipients (KTxR). However, increased medical and scientific advances in knowledge and management of KTx complications have raised questions about UTI as a pathological process that decreases and worsens kidney allograft function and survival. This review sought to clarify diagnostic criteria, as well as to describe factors associated with UTI in KTxR that expose its effects on the allograft. We sought to show the uncertainty of important topics within the field of UTI among kidney allograft recipients and to propose a practical clinical approach to KTxRs with UTI.