Chronic cholesterol crystal embolism: the value of kidney biopsy

A 63-year-old man with a history of smoking, obesity, arterial hypertension, diabetes mellitus, and previous deep venous thrombosis (DVT) in the left leg was admitted to the emergency department due to myocardial infarction.Upon admission, laboratory tests revealed serum creatinine of 2.3 mg/dL (normal, 0.9-1.3mg/dL) and urea of 79 mg/dL (normal, 10-40 mg/ dL).Coronary angiography revealed severe and complex lesions in all three arteries.Surgical myocardial revascularization was performed without complications.The patient was discharged on the 19th postoperative day in satisfactory condition with a creatinine of 1.93 mg/dL.However, he presented to the hospital again 7 days after discharge, complaining of chest pain and dyspnea.Chest angiotomography revealed a right-sided pulmonary embolism, while venous Doppler imaging of the lower limbs showed no signs of a recent DVT.The patient was started on full anticoagulation with unfractionated heparin, later transitioning to apixaban.Hematological investigations for hypercoagulable disorders yielded negative results.During outpatient follow-up, 24-hour proteinuria was 264 mg/day and creatinine level rose to 3.53 mg/dL.Doppler of the renal arteries showed abdominal aortic atheromatosis without significant stenosis, with a fusiform aneurysmal dilation in the infrarenal segment measuring approximately 8.4 cm in length and 4.4 cm in diameter,