Abstract
An 11-year-old, 12.3-kg, female Miniature Dachshund was presented to our institution with ascites of unknown etiology. The dog had been administered moxidectin for 3 years to treat a heartworm infection. Thoracic radiographs showed enlargement of the right heart. Echocardiography revealed right atrial and ventricular dilatation as well as flattening of the interventricular septum. Heartworm was identified in the main pulmonary artery, which was dilated. Tricuspid regurgitation (TR) was observed using color Doppler ultrasonography, and 2.5 L of ascites were removed. The dog was diagnosed with pulmonary hypertension, severe TR, and right-sided congestive heart failure. Except at the initial site, heartworm was not detected using echocardiography, and the antigen test was negative. However, pharmacological treatment did not improve the right-sided congestive heart failure. Instead, De Vega tricuspid annuloplasty (TAP) was performed on the beating heart under cardiopulmonary bypass with the owner's consent. Sutures terminated between the two commissures in the middle of the annulus and were secured using another pledget. Annular reduction was performed by tying down the plication suture while the cylindrical sizer was inserted into the tricuspid valve orifice. The size of the cylindrical sizer was 16 mm, which was set based on the height and width of the septal leaflet. A 6-month follow-up showed a reduction of TR and right-sided volume overload with no evidence of ascites retention/recurrence or any other complication. Our findings indicate that TAP may be a valid treatment option for dogs with right-sided congestive heart failure caused by secondary TR.
Highlights
Pulmonary hypertension (PH) leads to pressure overload in the right ventricle (RV), which induces right ventricular concentric and eccentric hypertrophy [1–4]
The efficacy of therapy for dogs with PH is limited by the occurrence of right ventricular dysfunction, which results in a tricuspid annular plane systolic excursion (TAPSE) of
We describe the successful treatment of tricuspid regurgitation (TR) secondary to PH using De Vega annuloplasty under cardiopulmonary bypass (CPB) in a dog
Summary
Pulmonary hypertension (PH) leads to pressure overload in the right ventricle (RV), which induces right ventricular concentric and eccentric hypertrophy [1–4]. Right ventricular eccentric hypertrophy can cause tricuspid regurgitation (TR) via annulus dilatation [1–4]. A 12-Fr and 14-Fr CPB cannula (DLP Cardiopulmonary Bypass Cannula, Medtronic, Tokyo, Japan) was inserted into the cranial and caudal vena cava via the RA, respectively. A regurgitation test after TAP was performed using saline, and closure of the tricuspid valve was confirmed (Figure 3F). Once the CPB was discontinued and the blood pressure was stable, the catheters were removed from the cranial and caudal vena cava and right carotid artery. Echocardiography showed good coaptation of the tricuspid valve and less interventricular septal flattening than was observed during the pre-operative period (Figures 4D,E). Echocardiography revealed mild tricuspid regurgitation (Figures 4C,F), but the sizes of the RA and RV had not changed from 1-month follow-up (right ventricular end-diastolic volume = 7.3 cm). The dose of sildenafil was reduced to 1 mg/kg per os, twice daily, and pimobendan was continued at the same dose (0.2 mg/kg orally twice a day)
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