Dissection of a Patent Ductus Arteriosus with Right Heart Failure in an Adult Dog

Abstract

A 3-year-old male, castrated, miniature pinscher weighing 9 kg was presented to the University of Zurich Veterinary Teaching Hospital Cardiology Service for evaluation of lethargy, a newly recognized cardiac murmur, and labored breathing. For the previous 3 days, the dog had been progressively reluctant to move and breathing had become labored. Before the current presentation, the dog had always been in excellent health.On admission, the dog was in sternal recumbency, profoundly lethargic, and showed expiratory dyspnea. Diffuse petechiation was visible on the skin and mucous membranes. Heart and pulse rate were 160 beats per minute and irregular, pulse quality was weak, and rectal temperature was 37.1uC (98.8uF). On auscultation, no respiratory or cardiac sounds were heard on the left side and muffled sounds were heard on the right side with a continuous heart murmur, grade 3/6. The jugular veins were distended and abdominal palpation disclosed hepatomegaly and ascites.Laboratory abnormalities on presentation included severe thrombocytopenia (11,000/mL; reference range, 130,000-394,000/mL), hypoproteinemia (43 g/L, reference range: 56-71 g/L), hypoalbuminemia (22 g/L, reference range: 29-37 g/L), hyponatremia (136 mmol/ L; reference range, 152-159 mmol/L), and hyperkalemia (5.4 mmol/L; reference range, 4.3-5.3 mmol/L). A coagulation profile was normal.An ECG indicated sinus tachycardia with single ventricular premature complexes and non-sustained ventricular tachycardia with a left bundle branch block pattern. The QRS complexes during sinus tachycardia were consistent with right ventricular enlargement and the ST segments were depressed in leads I, II, and aVF and increased in lead aVR.Thoracic radiographs revealed marked pleural effusion, moderate right heart enlargement, diminished pulmonary vasculature, engorged caudal vena cava, hepatomegaly, and ascites. Analysis of abdominal and pleural fluids indicated that they were modified transudates.On 2-dimensional and M-mode transthoracic echocardiography, a the right ventricle (RVDd, 2.45 cm) and right atrium (RA, 4 cm) appeared markedly dilated with flattening of the interventricular septum. The left ventricle was hypovolemic (LVDd, 1.4 cm). In the main pulmonary artery, a membranous structure that originated laterally slightly above the pulmonary valve annulus was bulging into the lumen (Fig 1a). An echodense structure suggestive of a thrombus at the site of the pulmonary artery bifurcation completely occluded the left pulmonary artery. Color Doppler echocardiography indicated moderate tricuspid insufficiency (TI), mild pulmonic insufficiency (PI), and continuous turbulent flow from the descending aorta to the main pulmonary artery through a patent ductus arteriosus (PDA). Furthermore, the systolic outflow signal above the pulmonary valve was only a narrow turbulent jet that passed medially to the described membrane. Behind the membrane, there was no systolic flow but only diastolic blood flow in the main pulmonary artery towards the pulmonary valve (Fig 1b). Sp...

Pulmonary artery dissection causing haemothorax in a cat: potential role of Dirofilaria immitis infection and literature review

“…Pulmonary artery dissection is a very unusual finding in veterinary medicine, since it has only been reported in dogs [6,7,8,9] and cattle [8].…”

“…University of Turin's Institutional Research Information System and Open Access Institutional Repository with patent ductus arteriosus [6,9] or anomalous vessels [8] is considered the main predisposing cause in dogs. Marfan's syndrome [10] and secondary degenerative cystic wall changes [9] are also reported as underlying causes in cattle and dogs, respectively.…”

“…However, Marfan's syndrome, cystic medionecrosis and systemic inflammation of unknown cause have also been reported as possible causes in patients without underlying pulmonary hypertension [17]. As opposed to humans, whose pulmonary artery appears more likely to rupture [18] with bleeding into pericardium, lungs, mediastinum or pleural cavity [17], rupture of the dissected pulmonary artery with bleeding into the perivascular tissue has only been observed in an adult dog [6].…”

Pulmonary artery dissection in eight dogs with patent ductus arteriosus

“…31 The authors are aware of 4 cases reported in the literature describing pulmonary artery dissections in dogs. 6,10e12 In the first 3 cases, the pulmonary artery dissection was associated with a concurrent aortic dissection either traversing a PDA, 10 spanning the ligamentum arteriosum, 11 or communicating in an uncertain location. 6 In the most recent report, the pulmonary artery dissection was associated with an anomalous vessel between the ascending aorta and main pulmonary artery, the embryology of which was uncertain.…”

“…8,9 Three prior descriptions of pulmonary artery dissection in the dog have all been associated with concurrent aortic dissection. 6,10,11 Recently, a pulmonary artery dissection was appreciated in a dog with an anomalous vessel between the ascending aorta and main pulmonary artery. 12 The aim of this case series is to describe pulmonary artery dissection in 8 dogs, each with a patent ductus arteriosus (PDA).…”