Post-cardiac surgery pulmonary hypertension

Abstract

T HE TREATMENT of postoperative pulmonary hypcrtension is one of the most difficult and challenging problems in the management of cardiac surgical patients. The causes of postoperative pulmonary hypertension include both primary and secondary etiologies. Secondary forms (ie, postcapillary) result from (1) left ventricular (LV) failure, (2) residual mitral stenosis, (3) thrombus in the left atrium, (4) car tritriatum, and (5) obstructive diseases of the pulmonary venous system. Intracardiac defects with residual right-to-left shunts are the leading cause of postoperative precapillary pulmonary hypertension. In these situations, impairment of pulmonary venous drainage with consequent elevation of pulmonary venous, artrial, and right ventricular (RV) pressures gives rise to persistently elevated pulmonary artery pressures (PAP) as a direct effect of the abnormally high pulmonary venous pressure (PVP).’ Although the causes of postoperative pulmonary hypertension may differ (ic, primary v secondary forms), the pathophysiologic response to the persistently elevated PAP and PVP are similar in all populations. Therefore, the major goal of any therapeutic regimen for the management of pulmonary hypertension is aimed at reducing pulmonary vascular resistance (PVR) and PAP in an attempt to prevent the development of RV dysfunction.