Transpulmonary Stent Implantation for Dysplastic Pulmonary Valve Stenosis with a Single Left Coronary Ostium and Anomalous Prepulmonary Right Coronary Artery in an English Bulldog

Agreement of echocardiographic and catheterization-based methods of transpulmonary pressure gradient measurement in dogs

INTRODUCTION/OBJECTIVES

Doppler echocardiographic estimation of transpulmonary pressure gradient (PG) is widely used to determine severity of pulmonary valve stenosis and indication for transcatheter intervention. The objective of this study was to describe agreement between Doppler echocardiographic methods of transpulmonary PG estimation and direct peak-to-peak pressure gradient at catheterization (PGcath) in dogs. We hypothesized that with reference to PGcath, mean echocardiographic PG (PGecho-mean) would have less bias than peak modal instantaneous echocardiographic PG (PGecho-peak).

ANIMALS

Client-owned dogs with congenital pulmonary valve stenosis that underwent balloon pulmonary valvuloplasty at one of two veterinary teaching hospitals between June 2012 and May 2022 were included in this study.

MATERIALS AND METHODS

Cases that underwent transthoracic echocardiography and subsequent balloon pulmonary valvuloplasty separated by 30 or fewer days were retrospectively identified. For each echocardiogram, average PGecho-mean (mmHg) and average PGecho-peak (mmHg) were calculated from stored spectral Doppler recordings. Peak right ventricular-to-peak pulmonary artery PG data (mmHg) were obtained from catheterization reports. Bland-Altman analysis was used to assess agreement between echocardiographic and catheterization data.

RESULTS

Data from 209 dogs (n = 215 instances) were evaluated. Proportional bias, greater at higher gradients, was observed for PGecho-mean versus PGcath (P<0.001). A constant bias of -38.12 mmHg was observed for PGecho-peak versus PGcath (P=0.62). Bias for both echocardiographic variables had wide limits of agreement that increased with PG.

CONCLUSIONS

Mean Doppler echocardiographic systolic transpulmonary pressure gradient and PGecho-peak underestimated and overestimated PGcath, respectively, preventing their interchangeability with PGcath.

Trans-pulmonary stent placement for pulmonary stenosis in a dog with a type R2A coronary artery anomaly

A one-year-old male intact American bulldog was presented for evaluation of previously diagnosed pulmonary stenosis. Echocardiography identified ultra-severe stenosis with an instantaneous trans-pulmonary pressure gradient of 240 mmHg. Angiography confirmed the presence of an anomalous coronary artery with a prepulmonic course of the left coronary artery arising from a single right coronary ostium consistent with a type R2A coronary anomaly. A trans-pulmonary stent was successfully placed transvenously with diameter sizing based on coronary compression testing. No coronary compression was present on postimplantation angiography. A marked reduction in the pressure gradient was obtained on postoperative echocardiography (reduction to 68 mmHg), despite selecting a stent diameter less than the pulmonary annulus diameter. This is the first report of the use of coronary compression testing in transvenous trans-pulmonic stent implantation in a dog with a type R2A coronary artery anomaly. Selection of a stent diameter less than the pulmonary annulus diameter conveyed a clinically relevant reduction in the trans-pulmonic pressure gradient while avoiding coronary compression in this case.

64-Slice ECG-gated computed tomographic angiography for assessment of coronary arteries in brachycephalic dogs with pulmonary stenosis

BACKGROUND

Brachycephalic dogs with pulmonary stenosis are known to have a higher incidence of concurrent coronary artery abnormalities than non-brachycephalic breeds, which increases risk when performing balloon valvuloplasty. The use of ECG-gated CT angiography has been reported for the evaluation of coronary arteries in normal dogs and dogs with pulmonary stenosis. The purpose of this study was to report findings of coronary artery origination and morphology of main branches using ECG-gated CT angiography in brachycephalic dogs with pulmonary stenosis.

METHODS

An ECG-gated CT angiographic protocol was used to image coronary artery anatomy in nine brachycephalic dogs with pulmonary stenosis. Images were assessed for quality as well as coronary artery morphology by one veterinary radiologist, one veterinary cardiologist and one veterinary radiology resident.

RESULTS

All nine dogs had good to excellent image quality. Coronary artery anomalies were identified in three of nine dogs: one R2A anomaly, one L2A anomaly and one L2C anomaly. Two dogs were assessed to be poor balloon valvuloplasty candidates based on CT angiographic images.

LIMITATION

Coronary artery morphology was not confirmed via postmortem examination in all patients.

CONCLUSION

ECG-gated CT angiography is a minimally invasive imaging modality capable of diagnosing various coronary artery anomalies in brachycephalic dogs with pulmonary stenosis and aiding in the determination of patient candidacy for balloon valvuloplasty.

Key considerations in the approach to congenital heart disease in dogs and cats

Congenital heart disease is an important subset of all cardiovascular disease in dogs and cats that is present at birth and most often detected in young animals but can be diagnosed in adulthood. The range of abnormalities that can occur during development of the heart is vast incorporating simple and complex defects, varying degrees of severity and clinical presentations that include heart failure and cyanosis. While some defects do not result in morbidity in an individual animal, others cause severe clinical signs and death at a young age. Advances in imaging and expanding treatment options offer increasingly more possibilities in the diagnosis and management of congenital heart disease which is the focus of this review. The objective is to provide a broad overview of current practice and highlight key aspects to guide practitioners in their approach to congenital heart disease diagnosis and knowledge of available treatment options.

Coronary arterial compression testing by simultaneous balloon valvuloplasty and coronary angiography in an English bulldog with pulmonary valve stenosis

A 4-year-old male neutered English bulldog presented for heart murmur evaluation. Echocardiography identified severe pulmonic stenosis (an echocardiography-derived transpulmonary pressure gradient of 100 mmHg), and computed tomography confirmed the presence of an anomalous coronary artery with a prepulmonic course of the left coronary artery arising from the right coronary ostium. Before artificial pulmonic valve implantation, a coronary compression test was performed. A simultaneous aortic root angiogram and pulmonic balloon valvuloplasty revealed complete occlusion of the circumflex branch. Artificial valve implantation was aborted with concern for fatal coronary compression after implantation. Coronary compression testing is a critical component of the evaluation before catheter-based implantation of conduits across the pulmonic valve.