CARDIOPULMONARY EFFECTS OF ENOXIMONE OR DOBUTAMINE AND NITROGLYCERIN ON MITRAL-VALVE REGURGITATION AND PULMONARY VENOUS HYPERTENSION

Objective: To compare the cardiovascular and pulmonary effects of the phosphodiesterase III inhibitor enoximone (EN) or a combination of dob utamine (DOE) and nitroglycerin (NTG) before and after mitral valve re pair or replacement. Design: Prospective, randomized, controlled clini cal study. Setting: University hospital. Participants:Twenty patients with mitral regurgitation and pulmonary venous hypertension scheduled for elective mitral valve surgery. Interventions: Patients fulfilling the inclusion criteria of the study were randomly allocated into a gro up treated with EN (group 1, n = 10) or DOE and NTG (group 2, n = 10). A cardiopulmonary Status was obtained after induction of anesthesia a nd mechanical ventilation during stable hemodynamic conditions (contro l). Then the patients received either EN (bolus dose 1.0 mg/kg followe d by a continuous infusion of 10 mu g/kg/min) or DOE (8.0 mu g/kg/min) and NTG (1.0 mu g/kg/min) according to the randomization. After a per iod of 20 minutes, all parameters were measured again. The study drugs were stopped, and cardiac surgery was performed. Infusions of EN (wit hout additional loading dose) or Dog and NTG were started again in the above-described doses 10 minutes before separation from cardiopulmona ry bypass (CPB). Respiratory and hemodynamic measurements were made 20 minutes after weaning from CPB and 60 minutes after admission of the patient to the intensive care unit. Measurements and Main Results: Bot h groups were comparable regarding preoperative and control data. Befo re mitral valve surgery, cardiac output (GO) and heart rate (HR) incre ased by 46% (p < 0.05) and 31% (p < 0.01) during infusion of EN with m inor changes of mean systemic arterial pressure (P-SA) and gas exchang e. Mean pulmonary arterial pressure (P-PA) decreased from 32 +/- 11 mm Hg to 23 +/- 11 mmHg (p < 0.05). Similar alterations were observed in group 2 (Delta CO + 26%, p < 0.05, Delta HR + 39%, p < 0.01); however, P-PA and calculated pulmonary vascular resistance remained unchanged. After separation from CPB, EN and DOB-NTG achieved comparable effects on CO, HR, and P-SA, but P-PA was significantly Tower in group 1. In addition, venous admixture and alveolo-arterial oxygen tension gradien t were lower in EN-treated patients. Conclusion: Enoximone or DOE and NTG have comparable effects on CO, P-SA, and HR in mitral regurgitatio n and pulmonary hypertension, but EN is more effective in reducing P-P A without deterioration of gas exchange. Copyright (C) 1997 by W.B. Sa unders Company.