Page 8 - RVC Clinical Connections - Spring 2025
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RVC RESEARCH STUDY VETERINARY SERVICES RVC.AC.UK
Cardiology
COMPLEX CARDIOLOGY CASE
Virginia Luis Fuentes (Professor of Veterinary Cardiology) and Eve Lo (Resident in Veterinary
Cardiology)
urphy, a nine-month-old male
Cockerpoo was presented to the
M RVC鈥檚 Emergency Referral Service
at the end of last April. He had become
acutely unwell and weak, and collapsed
after an episode of vomiting.
The owners took Murphy to his local vet
practice and, after receiving intravenous
fluid therapy and antibiotics, he was
discharged from his local vets, who referred
him to the RVC Emergency Referral Service
due to lack of improvement.
On admission Murphy was barely
responsive, with pale mucous membranes.
Auscultation revealed a grade III/VI left (Left) CT angiography of the sagittal plane, demonstrating the patent ductus arteriosus (PDA)
inserting onto the main pulmonary artery, which is severely dilated
basilar systolic heart murmur, and focal
inspiratory pulmonary crackles. His systolic (Right) Fluoroscopic image of Amplatz canine ductal occluder in place, with delivery sheath and wire
within the descending aorta. Transoesophageal echocardiography and fluoroscopy are used during
blood pressure was only 82 mmHg. procedures to measure the size of the PDA ostium and assess appropriateness of ACDO placement
Murphy was transferred to the RVC
Cardiology Service, and an echocardiogram demonstrated severe thrombocytopenia pulmonary hypertension. After discussion
revealed a patent ductus arteriosus (PDA), and leukocytosis, and despite no obvious with our Internal Medicine and Antibiotic
with low-velocity shunting of blood from external petechiae, rectal examination Stewardship teams, PDA closure was
the aorta through the PDA to the main revealed melena. planned for the following day.
pulmonary artery. There was evidence of Working with the Emergency Service, Murphy was anaesthetised by our
right-sided cardiac enlargement, suggestive the Diagnostic Imaging team conducted a Anaesthesia Team, and the Cardiology Team
of pulmonary hypertension. CT scan that confirmed findings consistent performed the catheterisation procedure via
Usually the blood flow through a PDA is with pneumonia, and Murphy continued his a small incision over the femoral artery. An
very high velocity, with substantial shunting improvement over the next couple of days. Amplatz canine ductal occluder (ACDO)
across the ductus that can lead to congestive His thrombocytopenia was thought to be device was positioned in the ductus, imaged
heart failure. In Murphy鈥檚 case, there was consumptive in origin, and resolved with using a combination of transoesophageal
very little shunting of blood across the management of his pneumonia, and he was echocardiography and fluoroscopy. The
ductus, because of pulmonary hypertension. discharged with antibiotics and an increased ACDO device was released, preventing
His pulmonary artery pressures were only dose of sildenafil, with plans to close his blood flow through the ductus.
slightly lower than the aortic pressure. PDA the following week. Murphy recovered from the procedure
The best management for dogs with a left- Murphy and the anaesthesia uneventfully, and there
to-right PDA is to close the ductus, ideally were no complications associated with his
with a catheter intervention. However, ductal pulmonary hypertension during or after
closure in dogs with a PDA and severe the intervention. After a month of restricted
pulmonary hypertension is contraindicated exercise it was possible to stop the
because once the PDA is closed, the right sildenafil, as the pulmonary hypertension
heart has to pump into a high resistance had resolved.
pulmonary arterial circuit. This sudden Left-to-right shunts are a recognised cause
increase in pulmonary vascular resistance of pulmonary hypertension, but in Murphy鈥檚
can result in death. However, without ductal case it is possible that his pneumonia also
closure, dogs with a PDA and pulmonary contributed. The contributions of the various
hypertension end up severely exercise clinical teams involved all helped to ensure
intolerant and develop erythrocytosis, Second admission Murphy was in optimum condition for his
because of low oxygen levels in the A week later, Murphy was bright, alert cardiac intervention, and he now has an
descending aorta. and clinically well at home. His murmur excellent chance of a normal life expectancy.
Murphy was started on sildenafil to reduce had changed to a grade V/VI left basilar The Animal Care Trust provided grant
pulmonary vascular resistance gradually. continuous murmur, more typical of a classic funding for the echocardiography machines,
We were delighted when Murphy responded PDA. His haematology and biochemistry CT scanner, and fluoroscopy equipment.
well to sildenafil, and PDA closure became results demonstrated a normal platelet
a possible option for him. However, although count and near-normal biochemistry. For small animal referrals, please call:
the sildenafil helped Murphy鈥檚 cardiovascular Echocardiography showed a more typical 01707 666399
system, he remained quiet and poorly cardiac phenotype consistent with a left- Email:
qmhreception@rvc.ac.uk
responsive. Murphy鈥檚 haematology results to-right shunting PDA, with no evidence of
8 Spring 2025
