Transthoracic echocardiography in healthy Diannan small-ear pigs

Pigs are widely used as large animal models in cardiovascular research. Establishing breed-specific physiological reference values is essential for experimental design and data interpretation.

Cardiac chamber dimensions, great vessel diameters, and hemodynamic parameters were systematically evaluated by transthoracic echocardiography (TTE) in 31 healthy Diannan small-ear pigs (mean weight: 47.2 ± 17.2 kg; 15 males, 16 females). Key structural indices were compared with human reference values. Animals were divided into three weight groups: 20-39 kg, 40-59 kg, and 60-80 kg.

Left and right atrial and ventricular diameters and volumes, as well as aortic and pulmonary artery diameters, increased significantly with body weight (P < 0.05) but remained smaller than human reference ranges (P < 0.05). Left ventricular wall thickness exceeded human values (P < 0.05), indicating a "small-cavity, thick-wall" structural phenotype. Left ventricular ejection fraction (LVEF) did not differ significantly from human values but decreased slightly in higher weight groups. Left ventricular diastolic function (E/e') and right ventricular systolic indices (fractional area change [FAC]) showed distinct weight-dependent patterns. Sex did not significantly affect any echocardiographic parameters.

Weight-associated variations reflect physiological cardiovascular development in Diannan small-ear pigs. This study provides baseline non-invasive echocardiographic data for this breed under isoflurane anesthesia. These data offer essential reference values for cardiovascular disease modeling, xenotransplant donor screening, and pre-operative assessment of novel cardiovascular technologies.