CLINICAL RISK ASSOCIATED WITH CONTRAST ANGIOGRAPHY IN METFORMIN TREATED PATIENTS - A CLINICAL REVIEW

Recently, concern has been expressed about the hazards of lactic acido sis following the use of intravascular iodinated contrast agents in pa tients taking metformin, In response the Royal College of Radiologists have issued guidelines for the management of these patients. Royal Co llege of Radiologists have issued guidelines for the management of the se patients. We have reviewed the reported cases of lactic acidosis an d identified that in all cases underlying renal impairment existed. To examine this further we reviewed the notes of 33 in-patients receivin g metformin who underwent contrast angiography in our hospital. Twenty -nine patients had a normal serum creatinine prior to the procedure an d none had a rise following angiography, Four patients had an abnormal serum creatinine prior to angiography, all four patients showed signi ficant deterioration and all four patients died, two from unrelated ca uses and two from acute renal failure and acidosis, These data strongl y highlight the hazards of intravascular contrast radiology in diabeti c patients with pre-existing renal impairment. We have failed to find evidence in support of the Royal College of Radiologists recommendatio n; instead we recommend that in those patients taking metformin with e vidence of renal impairment metformin should be stopped and diabetic c ontrol obtained using alternative therapy before proceeding with angio graphy, Patients with normal renal function taking metformin are not a t risk of lactic acidosis following the use of iodinated contrast agen ts for angiography.