Hemodynamic unloading of the failing left ventricle using an arterial-to-arterial extracorporeal flow circuit.

We tested the hypothesis that creation of a constant-flow extracorporeal circuit between the proximal and distal aorta will unload the failing left ventricle. Studies were performed in 14 heart failure dogs produced by intracoronary microembolizations. An extracorporeal circuit incorporating a diagonal pump was placed between a femoral and a carotid artery, with flow directed to the carotid. Hemodynamic measurements were made with the pump delivering 0.25 L/min through the circuit for 4 hours (active group). Measurements obtained from 8 sham-operated heart failure dogs were used for comparison (control group). Heart rate, peak left ventricular systolic pressure, left ventricular end-diastolic pressure, end-diastolic volume, end-systolic volume, and ejection fraction were measured at baseline and at 30, 60, 120, and 240 minutes. There were no differences in any of the hemodynamic values during the 4 hours of follow-up in the control group. In the active group, there was no effect on heart rate or peak systolic pressure, but reductions between baseline and 240 minutes were observed in left ventricular end-diastolic pressure (15 +/- 1 vs 6 +/- 1 mm Hg, p < 0.05), end-diastolic volume (61 +/- 3 vs 50 +/- 3 mL, p < 0.05), and end-systolic volume (44 +/- 2 vs 32 +/- 2 mL, p < 0.05), and an increase in ejection fraction (28 +/- 2 vs 37% +/- 2%, p < 0.05). Acute use of this artery-to-artery extracorporeal system effectively unloads the failing left ventricle. The potential benefits of this approach on long-term myocardial recovery in heart failure require further investigation.