Cholesterol emboli syndrome--uncommon or unrecognized?

Clinical and laboratory diagnosis of acute renal failure

Acute renal failure (ARF) is defined in general terms as an abrupt decrease in renal function sufficient enough to result in retention of nitrogenous waste and disrupt fluid and electrolyte homeostasis. There is no consensus regarding a quantifiable definition of ARF. Prompt evaluation of ARF is vital because ARF can be the end result of diverse processes which can often be reversed or attenuated through therapy directed at the underlying condition. Evaluation begins with careful review of the patient's history, previous medical records, physical examination, urinalysis, and available laboratory data. Routine urine chemical indices, calculation of the fractional excretion of sodium, and examination of the urine sediment are valuable in characterizing the cause of ARF. When this evaluation fails to yield a diagnosis, further testing may be required to evaluate intravascular volume status or diagnose a systemic disorder or glomerular cause of ARF. Response to therapeutic trials may provide a diagnosis. When a diagnosis cannot be made with reasonable certainty through this evaluation renal biopsy should be considered.

Contrast medium-induced acute renal failure and cholesterol embolism after radiological procedures: incidence, risk factors, and compliance with recommendations

BACKGROUND: After radiological procedures, the incidence of acute renal failure varies greatly, and cholesterol embolism may not always be recognized. Little, if anything, is known about whether recommendations for the prevention of either complication are correctly implemented. METHODS: We performed a prospective epidemiological study in a large population (n=809) of consecutive inpatients in a university hospital. The patients were monitored for risk factors, ongoing medications, and details of preventive measures and of radiological procedures. Contrast nephropathy was defined as a 25% rise in serum creatinine. Cholesterol embolism was defined by the presence of two typical signs. We analyzed the incidence, risk factors, and prevention of contrast nephropathy and cholesterol embolism. RESULTS: The most frequent procedure that our patients underwent was cardiac angiography (50%). The incidence of contrast nephropathy was 7%. We confirmed the classical risk factors (diabetes, dose of contrast medium, and renal insufficiency) and added potentially nephrotoxic medications as an independent risk factor. Fluid therapy, commonly proposed in high-risk patients, was adequately carried out in only 12% of patients. The incidence of cholesterol embolism was 4%, with 10% renal involvement. Arteriosclerosis and renal insufficiency were risk factors, but anticoagulation therapy was not. CONCLUSION: Adequate fluid therapy and discontinuation of nephrotoxic medications should be more systematically implemented in the prevention of contrast nephropathy. Recognition of cholesterol embolism is crucial.

Atheroembolism in cardiac surgery

BACKGROUND

Atheroembolism is a recognized complication of cardiac surgery, but its incidence and various outcomes have not been completely described. A retrospective study was undertaken to better characterize the syndrome.

METHODS

Records of 49,377 autopsies and surgical specimens from the Johns Hopkins Hospital between 1973 and 1995 were reviewed. Three hundred twenty-seven patients (0.7%) had an identifiable atheroembolism on histologic examination. Of these patients, 29 (0.2%) had undergone a cardiac surgical procedure within 30 days of autopsy or surgical resection. Patient charts and pathology specimens were reviewed for operative findings, postoperative outcomes, and histology.

RESULTS

Six of the 29 patients (21%) had atheroembolism to the heart, 7 patients (24%) had embolism to the central nervous system, 19 patients (66%) had embolism to the gastrointestinal tract, 14 patients (48%) had embolism to one or both kidneys, and 5 patients (17%) had embolism to a lower extremity. Sixteen patients (55%) had atheroembolism in two or more areas. In 6 patients (21%), death was directly attributable to atheroembolism, including intraoperative cardiac failure from coronary embolism (n = 3), massive stroke (n = 2), and extensive gastrointestinal embolization (n = 1).

CONCLUSIONS

Atheroembolism in cardiac surgery has a broad spectrum of clinical presentations, including devastating injuries and death. Although the true incidence is probably underestimated in this retrospective study, the high attendant mortality and morbidity of atheroembolism have been documented. Improvements in outcome are likely to be associated with preoperative identification of patients at high risk, modifications of perfusion technique, and interventions to minimize secondary thrombosis and progressive organ ischemia.

Recurrent renal cholesterol embolism

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