Pulmonary complications of a roller pump right ventricular assist device

The pulmonary effects of a right ventricular assist device (RVAD) were evaluated in a model of ischemic right ventricular (RV) failure. The right coronary artery (RCA) was ligated for 240 min in 12 mongrel dogs. Group 1 (n = 5) was supported medically (iv fluids, epinephrine); Group 2 (n = 7) had an RVAD instituted 30 mins after RCA ligation, but no inotropic support was given. The RVAD was a standard roller pump providing right atrial to pulmonary artery flow which unloaded the RV. The ratio of area of infarction (AI) to area at risk (AR) of the RV was determined by vital dye staining. Total lung water (TLW) was determined by gravimetric analysis and expressed as milliliters per kilogram body weight. Throughout the experiment animals in Group 1 had significantly higher RV systolic pressures. Pulmonary vascular resistance was increased significantly in Group 2 at 4 hr (318% of baseline vs 33%). Mean pulmonary artery pressure increased significantly in Group 2 from 9.4 +/- 0.9 mm Hg at baseline to 21.0 +/- 5.0 mm Hg at 4 hr. Group 2 animals had a decreased AI/AR ratio (19 +/- 3 vs 57 +/- 9) and increased TLW (20 +/- 3 vs 9 +/- 1). Lung biopsies in Group 2 revealed perivascular, peribronchial, and intraalveolar hemorrhages that were not present in Group 1. In conclusion, a roller pump RVAD limits RV infarction but produces pulmonary hypertension, increases pulmonary vascular resistance, and creates pulmonary edema and hemorrhage in the process.