Case report Unexpected benefits of participation in a clinical trial: abdominal aortic aneurysms in patients with chronic kidney disease

A 75-year-old man was referred to renal services in 2008 with a creatinine of 168mmol/l and an estimated glomerular filtration rate (eGFR) of 35ml/min/1.73m. He had a past history of hypertension and carcinoma of the prostate previously treated with radiotherapy. There was no history of diabetes or cardiovascular disease. On referral, he was taking perindopril 8mg, doxazosin 4mg and bendroflumethiazide 2.5mg with well-controlled blood pressure at 119/67mmHg. Total cholesterol was 4.9mmol/l. An abdominal ultrasound scan showed two kidneys (right 10.3 cm and left 11.6 cm) with moderate cortical thinning and no other pathology. He was followed up infrequently in the renal clinic as his renal function remained stable, his blood pressure was satisfactory and his cholesterol remained <5mmol/l. In June 2009, he agreed to participate in the CRIB-PHOS randomized controlled trial (evaluating the effects of sevelamer carbonate on cardiovascular structure and function in Chronic Renal Impairment in Birmingham). A lateral lumbar spine radiograph was performed to semi-quantitatively assess the presence and extent of abdominal aortic calcification at baseline as part of the study protocol. This showed heavy abdominal aortic calcification and a probable infra-renal aortic aneurysm measuring up to 6 cm (Figure 1a). Three days later, still as part of the trial, he underwent cardiac magnetic resonance imaging. With the patient’s consent, images were obtained of the abdominal aorta, which confirmed the presence of an infrarenal abdominal aortic aneurysm measuring 4.4 cm in the antero-posterior diameter with a rim of intraluminal thrombus (Figure 1b). The patient is now on the aneurysm surveillance programme having been urgently referred for a vascular surgical opinion and informed that a repair is likely to be required within 2 years.