This article describes the case of an 86-year-old coronary disease patient who underwent cardiac catheterization via a left radial access. Around 16 months after the procedure, he presented with dyspnea, unrelated to effort, but associated with nocturnal hypoxia. There was a palpable thrill in the left wrist and he was diagnosed with a radiocephalic arteriovenous fistula in the left wrist. A duplex scan revealed an abnormal wave pattern and increased diastolic velocity compatible with arteriovenous fistula. The fistula was repaired surgically and the patient exhibited improvement in clinical and laboratory parameters after the procedure. Radial access is increasingly being used for cardiac catheterization, primarily because it is associated with fewer and less harmful complications than femoral access. However, complications such as arteriovenous fistula occur and can be particularly harmful in octogenarian patients.