Intraaortic Balloon Pumping in Patients with Right Ventricular Insufficiency after Cardiac Surgery: Parameters to Predict Failure of IABP Support

Abstract

The indications for intra-aortic balloon pump (IABP) in the case of a failing right ventricle after operations with extracorporeal circulation (ECC) are still discussed controversially. We investigated the benefit of IABP in patients with a predominantly right ventricular dysfunction after ECC. Additionally, we wanted to identify early and easily available prognostic markers for outcome in all patients receiving IABP support. Between 1/2004 and 1/2008, 4550 patients underwent cardiac surgical procedures with ECC, 223 of whom (4.9 %) had an IABP inserted intra- or postoperatively (group 1). 79 of these patients were treated intraoperatively with IABP for early postoperative low cardiac output syndrome (LCOS) characterized by predominantly right ventricular failure (RV group). Clinical data and hemodynamic variables were recorded perioperatively. Multiple potential markers of mortality and postoperative complications were analyzed statistically, especially with regard to their predictive ability. 68 % of all IABP patients were successfully weaned from IABP support and 63 % survived to hospital discharge. In the RV group, cardiac index (CI) and mean arterial pressure (MAP) increased (CI 1.8 +/- 0.2 to 2.8 +/- 0.2, MAP 53 +/- 10 to 73 +/- 8, P < 0.05) within 1 hour after IABP, whereas central venous pressure (CVP) and pulmonary artery wedge pressure (PAWP) decreased ( P < 0.05). 59 patients in the RV group (75 %) could be weaned from IABP successfully and 69 % survived to hospital discharge. Serum lactate of more than 11 mmol/L in the first 10 hours of IABP support predicted a 100 % mortality. A base deficit of more than 12 mmol/L, mean arterial pressure less than 55 mmHg, urine output of less than 50 ml/h for 2 hours, and dose of epinephrine or norepinephrine of more than 0.4 mg/kg/min were other highly predictive prognostic markers. Furthermore, multivariate analysis showed that patients with a left atrial pressure > 17 mmHg or a mixed venous saturation (SVO (2)) < 65 % had poor outcomes. In patients with IABP support for postcardiotomy cardiogenic shock, elevated serum lactate, elevated base deficit, hypotension, oliguria and large vasopressor doses are all predictors of mortality. In these patients, the use of another mechanical assist device should be considered in good time. Our study additionally shows that LCOS caused by predominantly right ventricular failure - particularly after CABG - may be an additional indication for IABP.