Effect of transaortic catheter venting on left ventricular function during venoarterial bypass.

Although venoarterial bypass (VAB) or percutaneous cardiopulmonary support (PCPS) can improve hemodynamics in patients with serious cardiac decompression, some cannot be weaned from circulatory support. Insufficient unloading of the left ventricle (LV) with blood stagnation is a main cause of unsuccessful LV recovery during PCPS. This investigation was undertaken to evaluate the effectiveness of transaortic catheter venting (TACV) for LV unloading. Eight mongrel dogs (mean weight 16.3 kg, range 14-20 kg) underwent VAB with TACV. In addition to monitoring standard hemodynamic parameters, the slope of the LV end systolic pressure-volume relationship (Emax) during transient occlusion of the inferior vena cava, the slope of LV end systolic pressure-stroke-volume (Ea), external stroke work (SW), LV pressure-volume area (PVA), and slope of the SW-end diastolic volume relationship (preload recruitable stroke work: PRSW) were assessed by means of a micro-tip manometer and a conductance catheter. We measured data under the following four conditions; before circulatory support (baseline), during isolated VAB, VAB with TACV, and VAB with TACV plus intra-aortic balloon pumping (IABP). The LV contractility (Emax) and LV elastance (Ea) were equivalent for the four conditions. By comparison with baseline and VAB with TACV, LV energy (PVA) and work (SW, PRSW) were significantly reduced by TACV (1283.9 +/- 197.1 vs. 793.3 +/- 124.8 x 10(-4) J, 897.1 +/- 147.2 vs. 474.2 +/- 83.0 x 10(-4) J and 35.6 +/- 2.7 vs. 25.7 +/- 1.7 x 10(-4) J/ml, respectively), and the PE/PVA increased with TACV (30.4 +/- 2.6 vs. 40.8 +/- 1.8%). In contrast, there was no significant difference in PVA, SW, PRSW, and PE/PVA between baseline and isolated VAB. These results suggest that TACV might be an adjunctive technique to VAB or PCPS for patients with LV failure.