EFFECT OF TRANSAORTIC CATHETER VENTING ON LEFT-VENTRICULAR FUNCTION DURING VENOARTERIAL BYPASS

Although venoarterial bypass (VAB) or percutaneous cardiopulmonary sup port (PCPS) can improve hemodynamics in patients with serious cardiac decompression, some cannot be weaned from circulatory support. Insuffi cient 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 pre ssure-volume relationship (Emax) during transient occlusion of the inf erior vena cava, the slope of LV end systolic pressure-stroke-volume ( Ea), external stroke work (SW), LV pressure-volume area (PVA), and slo pe of the SW-end diastolic volume relationship (preload recruitable st roke work: PRSW) were assessed by means of a micro-tip manometer and a conductance catheter. We measured data under the following four condi tions; 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 fo r 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 i n PVA, SW, PRSW, and PE/PVA between baseline and isolated VAB. These r esults suggest that TACV might be an adjunctive technique to VAB or PC PS for patients with LV failure.