A 9-year-old spayed Labrador Retriever was presented for the closure of a patent ductus arteriosus (PDA) by coil embolization. The dog was asymptomatic, but a murmur had been detected 1 year earlier as an incidental finding. Clinical examination, electrocardiography, and thoracic radiography were consistent with a left-to-right shunting PDA without decompensation. The diagnosis was confirmed by 2-dimensional and M-mode echocardiography demonstrating volume overload of the left atrium and left ventricle, and color flow Doppler echocardiography detecting the presence of continuous turbulent retrograde flow in the pulmonary artery. The ductus was visualized, and no other congenital abnormalities were found. A CBC and serum biochemistry profile were obtained (Table 1). Prophylactic sodium cefazolin a was administered IV at a dosage of 20 mg/kg. An angiogram was performed under general anesthesia and fluoroscopic guidance by injecting 12 mL of the contrast agent sodium lothalamate b into the femoral artery. This procedure confirmed the diagnosis of a PDA and enabled the diameter at the pulmonary artery to be measured (10 mm) by comparison with a 2-cm marker on the pigtail catheter. The ductus was catheterized by a retrograde arterial approach with a 5-fr (1.7-mm) multipurpose catheter. c Four embolization coils (MWCE-10-PDA 5, MWCE-8-PDA 5, MWCE-8-PDA-4, and MWCE-5-PDA 5) d were positioned in the ductus ampulla. An angiogram performed after the procedure showed only a very small amount of residual flow through the ductus, and no murmur could be detected by the esophageal stethoscope. The femoral artery was ligated (2/0 silk), e and the wound was closed in a routine matter. The dog made an uneventful recovery and sodium cefazolin (20 mg/kg) was administered IV 2 more times at 8-hour intervals. A grade 2/6 continuous murmur was audible over the left heart base after recovery (4 hours after anesthesia). Thoracic radiographs documented coil placement (Fig 1).Eighteen hours after surgery (day 1) dark red-brown urine was noted. Urinalysis showed a specific gravity of 1.050, and Dipstick f testing disclosed proteinuria (100 mg/