Background: Right-side circulatory failure (RSCF), a common complication of heart transplant and left ventricular assist device recipients, results in decreased cardiac output because of diminished flow across the pulmonary circuit. We hypothesized that creation of a controlled venoarterial shunt would result in decompression of the right ventricle and improved systemic cardiac output at tolerable oxygen saturations.
Methods and results: A venoarterial shunt was created in a large-animal model (calf, n = 6). RSCF was induced by banding the pulmonary artery. Hemodynamic measures and blood gas determinations were obtained during nonshunted and shunted states. Pulmonary artery banding increased mean right ventricular systolic pressure from 44.9 +/- 2.1 mm Hg (mean +/- SEM) to 85.9 +/- 6.9 mm Hg (P < .05, paired t test) and decreased mean aortic flow from 7.8 +/- 1.0 to 4.2 +/- 1.1 L/min (P < .05). Flow through a venoarterial shunt at approximately 40% of cardiac output resulted in a decrease in right ventricular end-systolic pressure from 85.9 +/- 6.9 to 72.1 +/- 5.6 mm Hg (P < .01, ANOVA), a decrease in mean pulmonary artery pressure from 42.9 +/- 5.0 to 37.2 +/- 3.8 mm Hg (P < .01), and an increase in aortic flow from 4.2 +/- .05 to 5.1 L/min (P < .01). Left ventricular stroke work decreased from 2.22 +/- 0.28 to 1.55 +/- 0.88 (P < .05). Carotid artery oxygen saturation did not change significantly (99.9 +/- .02 to 97.6 +/- 1.7) during shunting.
Conclusions: A controlled venoarterial shunt improved hemodynamics and cardiac output in a large animal model with RSCF. This strategy may be useful in the management of transplant and left ventricular assist device recipients with perioperative RSCF.