Increased Renal Artery Diameter and Gross Hematuria
A 63-year-old former construction worker presents to his physician complaining about "dark urine" for the past 3 days. He also complains about left flank pain since this morning, which has made him come to the clinic. His past medical history is notable for hypertension, but despite being on antihypertensive treatment, his blood pressure remains uncontrolled. The patient also smokes one to two packs per day for the last 40 years, but he does not drink alcohol or use illicit drugs. He has no other medical problems. He is afebrile, his heart rate is 102 bpm and his respiratory rate is 14 bpm. His blood pressure is 150/95 mmHg. Laboratory findings are normal, except for a hemoglobin level of 9.5 g/dl and a hematocrit level of 32%. Upon further evaluation a contrast-filled outpouching was found in the course of the left renal artery.
Which of the following is most likely causing this patient's symptoms?