Kidney Function

We describe a case of acute kidney injury with decreased kidney perfusion in which contrast-enhanced computed tomography of the abdomen was performed for a nonrenal indication. This imaging procedure showed intrarenal blood flow redistribution from the cortex to the medulla that reversed after recovery of kidney function. Renal blood flow redistribution was described first almost a century ago in experimental models of renal ischemia, but clinical imaging studies are scarce. We provide a clear example of this phenomenon using contrast-enhanced computed tomography.

Background: Higher serum phosphorus levels are associated with cardiovascular disease (CVD) events in the general population, an association that may be stronger in men. Estradiol has phosphaturic properties. Whether higher serum phosphorus levels are associated with left ventricular (LV) mass in persons without end-stage renal disease and whether the association is modified by sex is unknown.Study Design: Cross-sectional observational study.Setting & Participants: 978 outpatients with stable CVD.Predictor: The primary predictor variable was serum phosphorus level. Sex was evaluated as an effect modifier.Outcome & Measurements: LV mass using transthoracic echocardiography.Results: The association of serum phosphorus level with LV mass differed by sex (interaction P = 0.04). In models adjusted for age, race, kidney function, smoking, diabetes, blood pressure, cholesterol level, C-reactive protein level, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use, each 1-mg/dL higher serum phosphorus level was associated with 4.52-g/m2 greater LV mass (95% CI, 1.04-8.01; P = 0.01) in men. Conversely, in women, no statistically significant association was found between serum phosphorus level and LV mass.Limitations: Older adult population with stable CVD; 19% were women.Conclusions: In outpatients with stable CVD, higher serum phosphorus levels are associated with greater LV mass in men, but not women. Whether sex hormones may account for these differences requires future study.

Background: Exposure to gadolinium in patients with kidney disease has been linked to risk of developing nephrogenic systemic fibrosis. The US Food and Drug Administration (FDA) has issued warnings against the use of gadolinium in this population. We studied the impact of these warnings on the use of gadolinium-enhanced magnetic resonance (GE-MR) studies in patients with decreased estimated glomerular filtration rate (eGFR) and the practice of measuring serum creatinine before gadolinium exposure.Study Design: Cross-sectional study of patients who had undergone MR studies from October 2002 to September 2008.Setting & Participants: Patients receiving medical care in the US Department of Veterans Affairs Health Care System.Predictor: Date of MR imaging, serum creatinine level, and eGFR using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation.Outcomes & Measurements: The rate of MR studies performed with and without gadolinium from July 2005 to September 2008 in patients with different stages of kidney disease, defined using eGFR. The proportion of GE-MR studies with a screening serum creatinine level.Results: There was a 71% decrease in the rate of GE-MR use in patients with GFR <30 mL/min/1.73 m2 2 years after the release of the first public health advisory, although studies continued to be performed in patients with stages 4 and 5 chronic kidney disease. The proportion of GE-MR studies with serum creatinine measured within 1 month before the study increased by 99%.Limitations: Data available up to September 30, 2008. Indications for the GE-MR studies were not assessed. The accuracy of Current Procedural Terminology and International Classification of Diseases, Ninth Revision coding was not assessed.Conclusion: There was a large decrease in the use of GE-MR studies in patients with GFR <30 mL/min/1.73 m2 and a large but not universal increase in the practice of measuring serum creatinine before GE-MR after the release of the FDA warnings.