Treatment of pulmonary hypertension in patients undergoing cardiac surgery with cardiopulmonary bypass: a randomized, prospective, double-blind study.

OBJECTIVE

Pulmonary hypertension can already be present in patients undergoing cardiac surgery or can be exacerbated by cardiopulmonary bypass. Postoperative treatment is still a challenge for physicians. The aim of this study was to evaluate the effects of inhaled prostacyclin (iPGI2) and nitric oxide (iNO) compared with those of intravenous vasodilators.

METHODS

This prospective, randomized, double-blind study included 58 patients affected by severe mitral valve stenosis and pulmonary hypertension with high pulmonary vascular resistance (> 250 dynes x s x cm(-5)) and a mean pulmonary artery pressure > 25 mmHg. All patients were monitored by central venous, radial arterial and Swan-Ganz catheters. Data were recorded at six different time points, before induction of anaesthesia, during and after surgery. Prostacyclin and nitric oxide were administered by inhalation 5 min before weaning from cardiopulmonary bypass and continued in the intensive care unit. Right ventricular function was evaluated by transoesophageal echocardiography.

RESULTS

Hospital mortality was 3.4%. After drug administration, the mean pulmonary artery pressure and pulmonary vascular resistance were significantly decreased in the iNO and iPGI2 groups with respect to the baseline values (P < 0.05) and such a decrease was maintained throughout the study; this was not observed in the control group. In the iNO and iPGI2 groups we demonstrated a significant increase in cardiac indices and right ventricular ejection fraction after drug administration with respect to baseline. Furthermore, patients in the inhaled drug groups were weaned easily from cardiopulmonary bypass (P = 0.04) and had a shorter intubation time (P = 0.03) and intensive care unit stay (P = 0.02) than the control group.

CONCLUSIONS

Our data suggest that both iNO and iPGI2 are effective in the treatment of pulmonary hypertension. iPGI2 has a number of advantages over iNO, including its easy administration and lower cost. Intravenous vasodilator treatment, on the other hand, is effective in terms of mortality but has a higher morbidity rate.