Renal toxicity of radiological contrast media

Contrast Induced Nephropathy: Efficacy of matched hydration and forced diuresis for prevention in patients with impaired renal function undergoing coronary procedures-CINEMA trial

BACKGROUND

Matched hydration and forced diuresis (MHFD) using the RenalGuard device has been shown to reduce contrast induced nephropathy (CIN) following coronary interventions.

AIM

To evaluate the potential benefits of a non-automated MHFD protocol compared to current hydration protocol in prevention of CIN in patients with CKD.

METHODS

A total of 1,205 patients were randomized to either non-automated MHFD group (n = 799) or intravenous hydration control group (n = 406). The MHFD group received 250 ml IV normal saline over 30 min before the coronary procedure followed by 0.5 mg/kg IV furosemide. Hydration infusion rate was manually adjusted to replace the patient's urine output. When urine output rate reached > 300 ml/h, patients underwent coronary procedure. Matched fluid replacement was maintained during the procedure and for 4-hour post-treatment. CIN was defined conventionally as ≥ 25% or ≥ 0.5 mg/dl rise in serum creatinine over baseline.

RESULTS

CIN occurred in 121 of 1,205 (10.0%) patients in our study. With respect to the primary outcome, 64 (8.01%) of the MHFD patients developed CIN compared with 57 (14.04%) of the control group (p < 0.001).

CONCLUSIONS

A non-automated MHFD protocol is an effective and safe method for the prevention of CIN in patients with CKD.

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.

Neuroimaging contrast agents in ophthalmology

Magnetic resonance (MR) imaging and computed tomography (CT) are routinely performed with the use of contrast materials in the diagnosis of neuro-ophthalmologic disease. Iodinated agents are commonly used in CT scanning and femoral contrast arteriography, and gadolinium is used in MR imaging. While contrast materials contribute greatly to diagnostic accuracy, they may also be responsible for adverse effects, ranging in severity from mild discomfort to death. The most frequent and severe side effects are associated with ionic iodinated contrast agents, while the rate of adverse reactions is less with use of nonionic iodinated contrast agents. Side effects and adverse reactions to gadolinium are uncommon, but they do occur. In neuro-ophthalmologic diagnosis, MR imaging is generally preferred over CT scanning, partly because of its greater ability to delineate soft tissue intracranial structures, but also because of the relative safety of gadolinium as a contrast agent. Properties of contrast agents are discussed in the context of specific imaging techniques and tissues investigated. Types and severity of adverse effects as well as risk factors for incurring such effects are summarized.

Induction, prevention and mechanisms of contrast media-induced acute renal failure

This study describes the development of an experimental model of reversible acute renal failure following infusion of contrast media radiographic dye. Experiments were also performed to investigate possible methods of prevention as well as examine single nephron mechanisms involved in the pathogenesis of the renal failure. Acute renal failure was consistently produced by indomethacin treatment (18 mg/kg) and an intravenous infusion of contrast media (7 ml/kg) into New Zealand rabbits that had been on a low sodium diet for one week. Glomerular filtration rate (GFR), measured by daily creatinine clearance in unanesthetized animals, was significantly decreased (P less than 0.001) 24, 48, and 72 hours following infusion of the contrast dye. Two weeks after induction of acute renal failure, GFR had returned to control. GFR was unchanged during the same time period when the sodium deprived rabbits were given either indomethacin or contrast media alone. Chronic administration of DOCA (1 mg/kg s.c.) and saline drinking water which increased sodium and solute excretions and decreased plasma renin activity also prevented the decrease in GFR. However, acute infusion of either saline or mannitol, which transiently increased sodium and solute excretions and decreased plasma renin activity, did not protect against the development of acute renal failure. Light microscopy revealed no glomerular or tubular changes and no visible obstruction. Micropuncture experiments were performed on three additional groups of anesthetized rabbits: control, acute renal failure, and recovery. Recovery rabbits were allowed a two week period after renal failure before they were micropunctured.(ABSTRACT TRUNCATED AT 250 WORDS)

Nephrotoxic tubular and interstitial lesions: morphology and classification

Nephrotoxic renal injury, and especially drug nephrotoxicity is now a common cause of acute renal failure. The most common patterns of renal injury produced by nephrotoxins, tubular damage, and interstitial nephritis, are discussed here. Toxic agents which are primarily tubular toxins include certain antibiotics, cisplatinum, anesthetics, and radiocontrast agents. In tubules injured by toxins, alterations range from subtle ultrastructural abnormalities to extensive tubular necrosis. Mechanisms of tubular injury include direct tubular cell toxicity, and alterations in intrarenal blood flow producing secondary tubular damage. Other commonly used therapeutic agents, including the penicillins, other antibiotics, and non-steroidal anti-inflammatory agents, produce renal dysfunction by inducing interstitial nephritis. Long-term analgesic abuse is associated with a particularly striking interstitial damage with frank papillary necrosis. Criteria for differentiating primary tubular injury with inflammation and primary interstitial nephritis with tubular injury are discussed. Individual commonly-used therapeutic agents are considered in some detail, with discussion of both clinical and morphological aspects of drug nephrotoxicity.

Radiologic contrast-induced nephropathy

Contrast nephropathy is the third most common cause of hospital-acquired renal insufficiency. While its exact pathogenesis is unclear, patients with existing renal disease are now known to be at increased risk for developing this complication. Identification of these patients by determination of serum creatinine levels may enable avoidance of contrast exposure or initiation of suitable therapy to minimize this complication if exposure to contrast is unavoidable.

Competitive action of contrast media on the uric acid-albumin binding

We investigated the competitive effect of iodinated contrast media on the binding of uric acid to albumin. This was an in vitro study utilizing the technique of equilibrium dialysis, with bovine serum albumin (BSA) as the protein substrate. It was demonstrated that some compounds, used for radiological visualization of the biliary passages, compete with uric acid for albumin binding. The meaning and clinical repercussions of this finding are discussed.

Transient acute renal failure and functional hemispheric depression after cerebral arteriography in diabetic patients

Cerebral angiography was carried out in two diabetic patients in the evaluation of minor vascular ischemic episodes. A transient acute renal failure following cerebral angiography was accompanied by a transient comatose episode with severe unilateral neurological deficits. A functional depression of the injected hemisphere due to a contrast induced impairment of the blood-brain barrier is suggested as the pathophysiological background of the neurological complication.

Pathogenesis of renal failure due to aminoglycosides and contrast media used in roentgenography

The etiology of acute renal failure has changed in recent years due to the recognition of drug nephrotoxicity as a more common cause. In this communication we emphasize recent information concerning the pathophysiology of nephrotoxic acute renal failure produced by aminoglycoside antibiotics and the contrast media used in roentgenography. The aminoglycosides are excreted primarily by glomerular filtration; however, net tubular reabsorption and renal parenchymal accumulation do occur. The exact mechanism of uptake is not clear, but the luminal membrane seems primarily involved. The pathogenesis of nephrotoxicity, although probably linked to cortical accumulation, is complex since experimental animals recover from gentamicin-induced renal failure despite continued administration of the drug. Knowledge of the precise cellular mechanisms of injury awaits further studies. Histologic damage is usually limited to proximal tubular necrosis and, clinically, the renal failure is nonoliguric. Although reports of the contrast media used in roentgenography producing acute renal failure have increased, the pathogenesis is unclear. Evidence supporting various theories is reviewed.

[Toxic nephropathies (author's transl)]

Direct tubular damage, hypersensitivity reaction, metabolically mediated kidney disturbances, and chronic nephropathies are important sequelae of several drugs or their metabolites. In this review the drug-induced kidney disease is discussed from a clinical, histological, and pathogenetic point of view. The knowledge of possible nephrotoxic reactions and their underlying toxins are essential for prevention of this kidney disease.

Effects of x-ray on a gravida with severe hemoconcentration: a case report

A gravida with severe hemoconcentration was studied with intravenous urography because of right upper quadrant pain. She subsequently developed renal failure. The potential hazard of urography in the presence of a severe blood volume contraction state is noted.

Renal failure following major angiography

Acute renal failure following angiography with contrast agents is known to occur, but the circumstances and frequency of its occurrence are not well described. A retrospective review of consecutive angiographic procedures performed over a six month interval revealed a 12 per cent incidence of renal failure following angiography. The degree of failure was severe in approximately 30 per cent of these cases and was associated with a significant mortality even though renal function usually recovered. The occurrence of renal failure was associated with the presence of renal insufficiency, impaired liver function, diabetes mellitus, hypoalbuminemia and proteinuria at the time of angiography to a statistically significant level. Furthermore, combinations of these factors, particularly preexisting combined renal insufficiency and impaired liver function, were associated with an increased incidence of acute renal failure. It is concluded that angiography poses a significant hazard to patients with underlying medical problems, particularly those involving the excretory routes of the contrast agent.

Antazoline-induced immune hemolytic anemia, hemoglobinuria, and acute renal failure

A case of repeated antazoline-induced immune hemolytic anemia, thrombocytopenia, hemoglobinuria, and acute renal failure is reported. The first episode of renal failure occurred after an i.v. pyelography causing an anaphylactic shock, and the two later episodes were preceded by allergic reaction to drugs. Antazoline was given among other remedies, but this drug was the only one used for treatment on every occasion. The clinical picture and the immunological tests, including an antazoline-dependent Coombs' test, indicate that the blood disorders might have been caused by a type 2 allergic reaction and renal lesion by a type 3 reaction, at least on the second and third occasions.

Renal consequences of valvular heart disease

Three aspects of potential renal involvement in patients with valvular heart disease are discussed. These include (1) disturbances in renal salt and water handling and their implications with respect to diuretic management; (2) the hemodynamic effects of angiographic contrast agents with identification of potentially dangerous effects on the kidneys; and (3) the histologic patterns of bacterial endocarditis in the kidney and their similarity to those of immunologically mediated disease.

Inhibition of active sodium transport by radiographic contrast media

We demonstrate that salts of diatrizoate and iothalamate, radiographic contrast agents, depress the active transport of sodium in the urinary bladder of the Columbian toad, Bufo marinus. Isolated toad bladders were incubated in isotonic Ringer's solutions with isosmolar displacement of sodium chloride by contrast media in experimental solutions. Sodium transport as measured both by short-circuit current (SCC) and by isotopic sodium flux was significantly depressed in the presence of sodium diatrizoate. Sodium transport measured by SCC was significantly depressed with sodium iothalamate and meglumine iothalamate. Equimolar methylsulfate Ringer's solution did not depress SCC. Although contrast media in isotonic Ringer's solutions depressed basal SCC, the vasopressin-stimulated increment in SCC was not depressed by contrast media. Separate experiments with hyperosmolar solutions (786 mM, as utilized in angiography) demonstrated equivalent suppression of SCC by contrast media and by other solutions made hyperosmolar with glucose or sodium methylsulfate, implying a general or nonspecific effect of hyperosomolarity. Inhibition of SCC by contrast media was reversible when the agents were removed by serial changes with standard Ringer's solution. Inhibition of sodium transport by contrast media might provide a basis for studies on some of the clinical toxicities of these agents.