Department of Clinical Studies, Small Animal Clinic (Internal Medicine and Surgery), Justus-Liebig-University Giessen
The occlusion of patent ductus arteriosus (PDA) in small canine patients is challenging for both surgical and interventional therapy. This prospective study examines the feasibility and success of transvenous coil embolization of patent ductus arteriosus in small dogs.
Inclusion criteria were a left-to-right shunting PDA and a body weight equal to or less than 3.0 kg. The presence of congestive heart failure was not considered an exclusion criterion. Patients with additional congenital cardiac diseases were excluded. Under general anaesthesia the right femoral vein was accessed percutaneously using a 4 French introducer sheet. The PDA was catheterized retrogradely with a 4 French wedge catheter, a 4 French multipurpose catheter and a 0.018 inch guide wire. After switching to an angiographic catheter the contrast medium was injected into the descending aorta. PDA morphology was classified and the minimal and ampulla diameter of the ductus were measured. A commercial 0.038 inch coil (Detachable Coil for PDA closure, Cook Deutschland GmbH) measuring at least twice the minimal diameter of the PDA was chosen. The coil was placed with approximately ½ loop of the coil anchored on the pulmonary side. An echocardiographic follow-up was performed within 24 hours post intervention.
Twenty one dogs underwent transvenous coil occlusion with Chihuahua and Yorkshire Terrier being the most common breeds (n=6 and n=5, respectively). The distribution of sex was 14 female and 7 male dogs. The ages of the patients ranged from 1.9 to 83.5 months (median 7.7 months), and the body weight from 1.0 and 2.9 kg (median 1.9 kg). The minimal diameter of the PDA measured 1.2 to 2.4 mm (median 1.8 mm) and the PDA ampulla 2.4 to 5.9 mm (median 4.6 mm). All but one PDA had an aortic ampulla and a pulmonary constriction (Type E n=16, Type A n=4). The remaining patient had two constrictions (one on the aortic and one on the pulmonary side, Type D). The coil implantation was successful in all patients. 7 dogs received a coil with a 3 mm loop-diameter while in the other 14 dogs a coil with a 5 mm loop-diameter was implanted. After the coil had been detached repositioning of the pulmonary loop of the coil with a 4 French wedge catheter became necessary in one dog. Two dogs developed temporary bradycardia after coil implantation requiring medical therapy. 16/21 (76%) dogs had no residual shunting in the follow-up echocardiography after 24 hours.
In conclusion: for an experienced cardiologist transvenous embolization of patent ductus arteriosus in small dogs is possible using a 4 French catheter and a commercial detachable coil. Arterial access is not essential and the procedure is safe and successful.