VARIABLE RESPONSE TO INHALED NITRIC-OXIDE AFTER CARDIAC-SURGERY

Background. Inhaled nitric oxide (NO) is a promising therapy that may be valuable in the control of pulmonary hypertension in cardiac surgic al patients. Patients with valvular heart disease have remodeling of t he pulmonary vascular bed that contributes to pulmonary hypertension. The purpose of this study was to compare the efficacy of inhaled NO in cardiac surgical patients with pulmonary hypertension with and withou t valvular heart disease. Methods. The effect of inhaled NO (40 ppm) o n pulmonary hemodynamics in patients with pulmonary hypertension (mean pulmonary artery pressure greater than or equal to 30 mm Hg) was stud ied in the operating room after cardiac operation. Fifteen patients wi th valvular heart disease comprised the study group; 25 patients under going aortocoronary bypass grafting were controls. Results. In patient s undergoing aortocoronary bypass grafting, inhaled NO produced a 24% decrease in mean pulmonary artery pressure (33 +/- 1 to 25 +/- 1 mm Hg ; p < 0.05), a 36% decrease in pulmonary vascular resistance (375 +/- 30 to 250 +/- 30 dyne . s . cm(-5); p < 0.05), and no change in system ic arterial blood pressure. On the other hand, patients with pulmonary hypertension from valvular heart disease did not respond to inhaled N O: mean pulmonary artery pressure was 39 +/- 3 mm Hg and pulmonary vas cular resistance was 620 +/- 30 dyne . s . cm(-5) before, during, and after NO. Conclusions. Among cardiac surgical patients with pulmonary hypertension, the response to inhaled NO is variable. Despite the prom ise of inhaled NO as a pulmonary vasodilator in cardiac surgical patie nts, these data suggest that alternative therapies are needed to contr ol pulmonary hypertension in patients with pulmonary hypertension from valvular heart disease. (C) 1997 by The Society of Thoracic Surgeons.