Effects of Early Inhaled Epoprostenol Therapy on Pulmonary Artery Pressure and Blood Loss During LVAD Placement

Abstract

Several strategies have been used to reduce the incidence of right ventricular failure after left ventricular assist device (LVAD) placement, including pulmonary vasodilation. The inhaled prostacyclin, epoprostenol, selectively dilates the pulmonary vasculature of ventilated areas of the lung, but also has been shown to inhibit platelet aggregation.(1) The authors evaluated the impact of early initiation of epoprostenol administration during LVAD placement on pulmonary artery pressures, use of vasoactive drugs, and blood loss. Retrospective data review. Single center, university hospital. A total of 37 consecutive patients undergoing LVAD (HeartMate II) placement were included. In the first group of 23 patients (group 1), inhaled epoprostenol was not initiated until weaning from cardiopulmonary bypass (CPB). In a subsequent group of 14 patients (group 2), inhaled epoprostenol was started shortly after induction of anesthesia and continued throughout and post-CPB. Mean and systolic pulmonary artery pressures (mPAP, sPAP), vasoactive drugs, as well as hemodynamic parameters, blood loss, and use of blood products were recorded at the following time points: Baseline (BL), pre-CPB, post-CPB, and during postoperative days (POD) 0, 1, and 2. Data are presented as mean±SD or median [25%, 75%]. Groups did not differ in demographic characteristics and comorbidities. BL sPAP (41±13 v 46±15 mmHg; p = 0.051) and mPAP (32±8 v 34±8 mmHg; p = 0.483) values were not different between the groups. Systolic and mPAP in group 1 were significantly lower in the postoperative period compared with BL (sPAP on POD 0: 34±6 mmHg; p<0.001; mPAP on POD 0, 1, and 2: 24±4 mmHg, 25±4 mmHg, 27±6 mmHg; p<0.001-0.003)). In contrast, in group 2, sPAP as well as mPAP were significantly lower during weaning from CPB (sPAP: 37±8; p = 0.002; mPAP: 28±5 mmHg; p = 0.016) as well as in the postoperative period (sPAP on POD 0, 1 and 2: 34±7, 35±7, and 37±10 mmHg; p<0.001-0.004; mPAP on POD 0, 1, and 2: 24±4 mmHg, 25±5 mmHg, 27±6 mmHg; p<0.001-0.006). Blood loss on postoperative day 0 was significantly lower in group 1 (1646 mL [1137, 2300] v 2915 mL [2335, 6155]; p = 0.006). Epoprostenol was a significant predictor of blood loss in the regression model (p<0.001) but did not predict a change in sPAP. Inhaled prostacyclin reduces sPAP and mPAP in the postoperative period after LVAD placement regardless of the timing of initiation. Early initiation seems to reduce sPAP as well as mPAP more effectively during the weaning process from CPB. However, early initiation is associated with an increased blood loss in the immediate postoperative period. The concept of preventively "bathing" the lung in prostacyclin should be evaluated critically in a prospective fashion to adequately examine this question.