Cholesterol crystal embolism: A recognizable cause of renal disease

Abstract

• Cholesterol crystal embolism, sometimes separately designated atheroembolism, is an increasing and still underdiagnosed cause of renal dysfunction antemortem in elderly patients. Renal cholesterol crystal embolization, also known as atheroembolic renal disease, is caused by showers of cholesterol crystals from an atherosclerotic aorta that occlude small renal arteries. Although cholesterol crystal embolization can occur spontaneously, it is increasingly recognized as an iatrogenic complication from an invasive vascular procedure, such as manipulation of the aorta during angiography or vascular surgery, and after anticoagulant and fibrinolytic therapy. Cholesterol crystal embolism may give rise to different degrees of renal impairment. Some patients show only a moderate loss of renal function; in others, severe renal failure requiring dialysis ensues. An acute scenario with abrupt and sudden onset of renal failure may be observed. More frequently, a progressive loss of renal function occurs over weeks. A third clinical form of renal atheroemboli has been described, presenting as chronic, stable, and asymptomatic renal insufficiency. The renal outcome may be variable; some patients deteriorate or remain on dialysis, some improve, and some remain with chronic renal impairment. In addition to the kidneys, atheroembolization may involve the skin, gastrointestinal system, and central nervous system. Renal atheroembolic disease is a difficult and controversial diagnosis for the protean extrarenal manifestations of the disease. In the past, the diagnosis was often made postmortem. However, in the last decade, awareness of atheroembolic renal disease has improved, enabling us to make a correct premortem diagnosis in a number of patients. Correct diagnosis requires the clinician to be alert to the possibility. The typical patient is a white man aged older than 60 years with a baseline history of hypertension, smoking, and arterial disease. The presence of a classic triad characterized by a precipitating event, acute or subacute renal failure, and peripheral cholesterol crystal embolization strongly suggests the diagnosis. The confirmatory diagnosis can be made by means of biopsy of the target organs, including kidneys, skin, and the gastrointestinal system. Thus, Cinderella and her shoe now can be well matched during life. Patients with renal atheroemboli have a dismal outlook. A specific treatment is lacking. However, it is an important diagnosis to make because it may save the patient from inappropriate treatment. Finally, recent data suggest that an aggressive therapeutic approach with patient-tailored supportive measures may be associated with a favorable clinical outcome.

Predictors of Renal and Patient Outcomes in Atheroembolic Renal Disease

“…Signs of central nervous system involvement, gastrointestinal symptoms, presence of eosinophilia as well as the rate of renal function deterioration were considered to evaluate the severity of the disease. Detailed description of diagnostic criteria have been reported elsewhere (2).…”

“…A preexisting chronic renal impairment was defined by the presence of serum creatinine levels of Ն 1.5 mg/dl in men and Ն 1.3 mg/dl in women; it was also very conservatively defined as a calculated GFR Յ 50 ml/min. With respect to the clinical presentation of AERD, renal failure was defined as acute if a sudden 50% increase of serum creatinine level was evident within 1 wk after the precipitating event; as subacute if the same amount of deterioration occurred in a stepwise fashion over 2 to 6 wk; as chronic if the patient had a stable renal impairment (2).…”

“…In the last decade, some clinical studies have increased our understanding of AERD, enabling us to make premortem diagnosis. The presence of a triad characterized by a precipitating event, subacute renal failure, and peripheral cholesterol embolization strongly suggests the diagnosis, which can be confirmed by the biopsy of the target organs (1)(2)(3)(4)(5)(6).…”

Chronic Cholesterol Crystal Embolism with a Spontaneous Onset

“…reciprocals of serum creatinine (1)(2)(3)(4)(5)(6), it can occur spontaneously in about 10% of cases (5,6). Clinically, three types of atheroembolic renal disease have been described (5) (6).…”

“…Clinically, three types of atheroembolic renal disease have been described (5) (6). There are isolated reports suggesting that corticosteroids (8)(9)(10)(11) or LDL apheresis (10,12) …”