The vena cavae of nine sheep weighing 62聽卤 2 (SEM) kg were injected with 0.375 g of dextran beads (sephadex) every day for 60 d. Pulmonary hemodynamics were assessed via pulmonary artery catheterization prior to the first injection and again on d 14, 28, 35, 42, 49, and 56. At the end of the experiment, the heart was removed, dissected, and weighed to determine the ratio of right ventricular mass to left ventricle plus septal mass (RV:LV+S).
All sheep survived to 60 d. The average pulmonary artery pressure rose from 17 卤 1 mmHg at baseline to 35 卤 3 mmHg on d 56 with no significant change in cardiac output (8.7 卤 0.7 to 9.8 卤 0.7 L/min, P = 0.89). The RV:LV+S was significantly higher (0.42 卤 0.01, P < 0.001) than a historic group of untreated normal animals (0.35 卤 0.01, n = 13).
This study provides a low-mortality large animal model of moderate chronic pulmonary hypertension and right ventricular hypertrophy.