Abstract: Background – Computed tomography (CT) aids planning of structural heart interventions in human medicine. Device sizing for pulmonary valve stenosis (PS) intervention in dogs relies on 2-dimensional (2D) imaging.
Objective – Obtain detailed measurements of the pulmonary outflow tract in dogs with PS.
Animals – Retrospectively-gated cardiac CT datasets from 64 PS dogs.
Methods – Retrospective study. End-diastolic (ED) and end-systolic (ES) right ventricular (RV) volumes were calculated. Area, perimeter, and minimum/maximum diameter of the pulmonary outflow tract were obtained at eight levels, both at ED and ES. The pulmonary valve annulus (PVA) area-derived diameter and annular eccentricity were calculated. Percent leaflet fibrosis was evaluated at PVA, mid-sinus, and sino-tubular junction (STJ).
Results – Median (range) RV ED and ES volumes were 7.30 (4.23, 12.15) and 16.45 (11.75, 28.23) mL, with ejection fraction of 58% (43, 70). Median PVA maximal diameter was 13.85 (12.20, 16.75) mm, minimal diameter was 11.15 (9.20, 13.15) mm, and PVA area-derived diameter was 12.40 (10.73, 14.75) mm. Change of PVA area-derived diameter from ED to ES was 2.95% (-3.15, 13.28). PVA eccentricity was 0.2 (0.14, 0.28), suggesting ovoid geometry. Pulmonary valve opening area was 24.0 (17.0, 36.8) mm2, averaging 19.9% of PVA area. The greatest fibrosis area (57.5%) was present at the STJ, ranging from 34.3% to 69.5%.
Conclusions – Eccentricity of the PVA suggests that measurements obtained from 2D imaging may underestimate or overestimate size of device. Fibrosis of the leaflets, particularly the STJ, was a dominant lesion in this population of PS dogs.
