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.