Intestinal manifestations with a surface-treated AN69 membrane and ACEI during haemodialysis.

Sir, AN69-associated reactions in haemodialysed patients receiving angiotensin-converting enzyme inhibitors (ACEI) are well-documented [1]. The negatively charged AN69 membrane is thought to activate the bradykinin system. Moreover, ACEI reduces bradykinin inactivation. Surface-treated AN69 is considered to be safer in that regard. To our knowledge, only one case of anaphylactoid reaction induced by ACEI during haemodialysis with a surface-treated AN69 membrane has been reported [2]. We report here two patients who had a more subtle presentation with predominantly intestinal manifestations. A 54-year-old male with end-stage renal disease (ESRD) consequent to IgA nephropathy had been on chronic haemodialysis (4 h, three times per week) for 2 years. He was dialysed using a surface-treated AN69 membrane (Nephral ST Õ 500, Gambro) for 4 months. His medication included metoprolol, furosemide, amiodarone, calcium car-bonate, sevelamer, allopurinol, oxybutinin, epoetin-a, calci-tonin, warfarin and naproxen. On 8 November 2004, ramipril 2.5 mg once daily was initiated for hypertension and cardiovascular protection. At the next dialysis, the patient presented moderate abdominal cramping and diarrhoea during haemodialysis. These symptoms did not recur until 19 November. They were present on 22 and 24 November, when medical attention was first requested. At this time, the working diagnosis was viral gastroenteritis. However, by caution, the dialyser was changed for a cellulose triacetate membrane (Exeltra Õ 210, Baxter). Abdominal gastrointestinal symptoms and diarrhoea completely disappeared with the new dialyser. The surface-treated AN69 membrane was then reintroduced on 1 December 2004. Less than 1 hr after the beginning of haemodialysis, severe abdominal cramps and diarrhoea occurred again. The patient had diaphoresis but no breathing problems or angiooedema. The blood pressure remained stable. The treatment was immediately stopped. Intravenous diphenhydramine 50 mg and hydrocortisone 100 mg were given. Symptoms resolved rapidly, and haemodialysis was started again with a cellulose triacetate membrane dialyser without any other adverse event. Ramipril was maintained. A 47-year-old man on chronic haemodialysis 4 h three times a week since October 2003 was known to have type 2 diabetes. He was dialysed using a surface-treated AN69 membrane since the first dialysis treatment. His medication included metoprolol, calcium carbonate, aspirin, alfacalcidol, glicazide, furosemide, temazepam and enalapril 2.5 mg four times a week. Enalapril was prescribed from 2003 but compliance was variable. From August to December 2004, enalapril was taken less than once a week. After January 2005, he took enalapril 2.5 mg four times a week, more regularly. In September 2004, he presented two …