Cholesterol crystal embolism: diagnosis and treatment.

Cholesterol crystal embolization (CCE) is a dreaded complication of radiology, vascular surgery, and/or anticoagulation in patients with atherosclerosis and ulcerated aortic plaques. It also represents a cause of early graft failure and of poor results of renal artery surgery. Crystals lodge in small caliber renal arteries, where they induce early, transitory thrombosis followed by delayed, definitive obstruction by endarteritis, accompanied by evidence of inflammation and eosinophilia. Massive CCE leads to early oligoanuria. In subacute forms, renal insufficiency is often delayed by weeks or months following the triggering event. A third, chronic subset of CCE is easily mistaken for atherosclerotic renal ischemia and/or nephrosclerosis. The kidney is rarely the sole organ involved in acute/subacute forms, in which the central nervous system, the coronary arteries, the spinal cord, and the mesenteric and pancreatic blood supply compromise represent the main causes of death. Cutaneous, retinal, and muscle involvement allow diagnosis by inspection or scarcely invasive biopsies in about 80% of cases, whereas renal biopsy as the only diagnostic procedure is required in 20% of cases. Prevention is based on avoidance of endovascular radiology maneuvers, vascular surgery, and excess anticoagulation in atherosclerotic patients. Treatment of acute/subacute forms of renal insufficiency consisting of stopping anticoagulation and forbidding any new radiologic and/or vascular surgery procedure; treating hypertension with angiotensin 2 antagonists and vasodilators, strict volemic control by loop diuretics and ultrafiltration, along with parenteral nutrition and prednisone, has been credited with improved outcome. Iloprost may obtain favorable results. Statins definitely ameliorate the renal and patient's prognosis.