Defining contrast-induced nephropathy

Predictors and Outcomes of Postcontrast Acute Kidney Injury after Endovascular Renal Artery Intervention

PURPOSE

To determine incidence, predictors, and clinical outcomes of postcontrast acute kidney injury (PC-AKI) following renal artery stent placement for atherosclerotic renal artery stenosis.

MATERIALS AND METHODS

This retrospective study reviewed 1,052 patients who underwent renal artery stent placement for atherosclerotic renal artery stenosis; 437 patients with follow-up data were included. Mean age was 73.6 years ± 8.3. PC-AKI was defined as absolute serum creatinine increase ≥ 0.3 mg/dL or percentage increase in serum creatinine ≥ 50% within 48 hours of intervention. Logistic regression analysis was performed to identify risk factors for PC-AKI. The cumulative proportion of patients who died or went on to hemodialysis was determined using Kaplan-Meier survival analysis.

RESULTS

Mean follow-up was 71.1 months ± 68.4. PC-AKI developed in 26 patients (5.9%). Patients with PC-AKI had significantly higher levels of baseline proteinuria compared with patients without PC-AKI (odds ratio = 1.38; 95% confidence interval, 1.11-1.72; P = .004). Hydration before intervention, chronic kidney disease stage, baseline glomerular filtration rate, statin medications, contrast volume, and iodine load were not associated with higher rates of PC-AKI. Dialysis-free survival and mortality rates were not significantly different between patients with and without PC-AKI (P = .50 and P = .17, respectively).

CONCLUSIONS

Elevated baseline proteinuria was the only predictor for PC-AKI in patients undergoing renal artery stent placement. Patients who developed PC-AKI were not at greater risk for hemodialysis or death.

Furosemide with saline hydration for prevention of contrast-induced nephropathy in patients undergoing coronary angiography: a meta-analysis of randomized controlled trials

Background

The clinical efficacy of furosemide administration in preventing contrast-induced nephropathy (CIN) remains uncertain. This meta-analysis was designed to update data on the incidence of CIN with additional furosemide treatment beyond saline hydration in comparison with hydration alone in patients undergoing percutaneous coronary intervention (PCI).

Material/Methods

A computerized literature search of MEDLINE, EMBASE, and Cochrane databases was performed. Trials were eligible if they enrolled patients undergoing coronary angiography and randomly allocated participants to receive furosemide administration in addition to saline hydration or saline hydration alone. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for combinations of studies.

Results

Five trials involving 1294 patients (640 for additional furosemide treatment and 654 for hydration alone) were included in the meta-analysis. In the synthesis of data, additional furosemide administration had little impact on the incidence of CIN post-PCI compared with peri-procedural saline hydration alone (OR=0.96; 95% CI 0.33–2.84, p=0.95). Moreover, as for the subsequent need for dialysis, there was no statistical significant difference between the 2 groups (OR=1.01; 95% CI 0.38–2.67, p=0.99). Sensitivity analyses did not show any relevant influence on the overall results. There was no publication bias in the meta-analysis.

Conclusions

Furosemide administration did not achieve additional benefit beyond saline hydration in reducing the incidence of CIN in patients undergoing PCI.

Radiographic contrast-media-induced acute kidney injury: pathophysiology and prophylactic strategies

Contrast-induced acute kidney injury (CI-AKI) is one of the most widely discussed and debated topics in cardiovascular medicine. With increasing number of contrast-media- (CM-) enhanced imaging studies being performed and growing octogenarian population with significant comorbidities, incidence of CI-AKI remains high. In this review, pathophysiology of CI-AKI, its relationship with different types of CM, role of serum and urinary biomarkers for diagnosing CI-AKI, and various prophylactic strategies used for nephroprotection against CI-AKI are discussed in detail.

How to reduce nephropathy following contrast-enhanced CT: a lesson in policy implementation

In excess of 50 contrast-enhanced computed tomography (CT) examinations are typically undertaken in our tertiary hospital NHS Trust each weekday, approximately 13,000 each year. In the Department of Radiology alone, we inject more than 1300 l of iodinated contrast medium per annum. There is a real need to devise a policy to anticipate contrast medium-induced nephropathy (CIN) and minimize its effects, without disrupting the high-intensity CT service. Having written a comprehensive yet pragmatic policy to reduce the incidence of this iatrogenic condition, it seemed sensible to share it with the wider radiology community and share the experience and lessons learnt in engaging all the stakeholders, ushering in the change with as little fuss as possible. The ramifications on primary and secondary care had to be anticipated, resource implications managed, and staff trained. This review is therefore presented in four sections: framing the problem, assessing its size and nature; a succeeding section on the available guidelines and their uptake; the policy itself to reduce CIN in CT is presented in the third section; and crucially, a description of the policy introduction process in the last section.

[Acute kidney injury]

Acute kidney injury (AKI) is defined as an abrupt decline in the glomerular filtration rate with accumulation of nitrogenous waste products and the inability to maintain fluid and electrolyte homeostasis. Occurring in 7% of all hospitalized patients and 28% to 35% of those in intensive care units, AKI increases hospital mortality. Early evaluation should include differentiating prerenal and postrenal components from intrinsic renal disease. Biological markers can give early warning of AKI and assist with differential diagnosis and assessment of prognosis. The most effective preventive measure is to maintain adequate circulation and cardiac output, avoiding ischemia- or nephrotoxin-induced injury. To that end, patients and situations of risk must be identified, hemodynamics and diuresis monitored, hypovolemia reversed, and nephrotoxins avoided. Protective agents such as sodium bicarbonate, mannitol, prostagiandins, calcium channel blockers, N-acetyl-L-cysteine, sodium deoxycholate, allopurinol, and pentoxifylline should be used. Treatment includes the elimination of prerenal and postrenal causes of AKI; adjustment of doses according to renal function; avoidance of both overhydration and low arterial pressure; maintenance of electrolytic balance, avoiding hyperkalemia and correcting hyperglycemia; and nutritional support, assuring adequate protein intake. For severe AKI, several modalities of renal replacement therapy, differentiated by mechanism and duration, are available. Timing--neither the best moment to start dialysis nor the optimal duration--has been not established. Early detection of AKI is necessary for preventing progression and starting renal replacement therapy at adjusted doses that reflect metabolic requirements.

Pharmacological management of cardiorenal syndromes

Cardiorenal syndromes are disorders of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other. The pharmacological management of Cardiorenal syndromes may be complicated by unanticipated or unintended effects of agents targeting one organ on the other. Hence, a thorough understanding of the pathophysiology of these disorders is paramount. The treatment of cardiovascular diseases and risk factors may affect renal function and modify the progression of renal injury. Likewise, management of renal disease and associated complications can influence heart function or influence cardiovascular risk. In this paper, an overview of pharmacological management of acute and chronic Cardiorenal Syndromes is presented, and the need for high-quality future studies in this field is highlighted.

Cardio-renal syndromes: report from the consensus conference of the acute dialysis quality initiative

A consensus conference on cardio-renal syndromes (CRS) was held in Venice Italy, in September 2008 under the auspices of the Acute Dialysis Quality Initiative (ADQI). The following topics were matter of discussion after a systematic literature review and the appraisal of the best available evidence: definition/classification system; epidemiology; diagnostic criteria and biomarkers; prevention/protection strategies; management and therapy. The umbrella term CRS was used to identify a disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ. Different syndromes were identified and classified into five subtypes. Acute CRS (type 1): acute worsening of heart function (AHF–ACS) leading to kidney injury and/or dysfunction. Chronic cardio-renal syndrome (type 2): chronic abnormalities in heart function (CHF-CHD) leading to kidney injury and/or dysfunction. Acute reno-cardiac syndrome (type 3): acute worsening of kidney function (AKI) leading to heart injury and/or dysfunction. Chronic reno-cardiac syndrome (type 4): chronic kidney disease leading to heart injury, disease, and/or dysfunction. Secondary CRS (type 5): systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney. Consensus statements concerning epidemiology, diagnosis, prevention, and management strategies are discussed in the paper for each of the syndromes.