Case Studies In Small Animal
Intervention (Coil Embolization)
Instead of correcting the PDA surgically, the PDA was closed using two small stainless steel coils covered with synthetic fibers to stimulate thrombosis (coil shown coming out of a catheter below on the right).
Chico was anesthetized and transesophageal echocardiography was performed. A view of the pulmonary artery (PA) end of the PDA (D) is shown below.
The opening in the pulmonary artery end was 3.5 mm wide. Generally a coil approximately twice the diameter of the ductal opening is used for coil embolization. A surgical cutdown and catheter placement in the right femoral artery was attempted but we could not thread catheter (the cutdown was too low on the artery). The right femoral artery was ligated. A higher cutdown on the left femoral artery was performed. A 5 French catheter was passed via this vessel into the proximal descending aorta. An angiogram (below) was taken to visualize the location of the PDA (arrow).
This location was then marked on the video screen so the catheter could be accurately placed into the PDA. MPA - main pulmonary artery; D - ductus; Ao - aorta
Once the catheter was positioned correctly, a 5mm (width) x 5cm (length when uncoiled) detachable coil deployment was initially attempted. However, this was too small to remain in the ductus (it kept being pushed by blood flow through the pulmonary artery end of the ductus into the main pulmonary artery). Two coils were subsequently placed in the ductus. The first one was an 8 mm (width) x 5 cm (length when uncoiled; Cook non-detachable) coil (shown deployed below on the left).
The second one was a 5 mm x 5 cm (Cook non-detachable) coil second on top of the first. Following the placement of the first coil, the following change in systemic blood pressure was recorded (ECG on top; systemic arterial blood pressure on the bottom).
As can be seen, the diastolic pressure increased immediately after the coil was placed and as the PDA was occluded (middle of the pressure trace).
The post-coil transesophageal echocardiogram shows the coil and a large thrombus (arrow) in the pulmonary artery end of the ductus arteriosus (above).
There were two small color flow Doppler jets through the thrombus and the ductus following the coiling procedure (below).
An angiogram following the procedure showed the coils in the ductus and no evidence of contrast agent in the pulmonary artery. The left femoral artery was closed after the procedure with a purse string suture so as to maintain patency.
©Mark D. Kittleson, D.V.M., Ph.D. All rights reserved.