Milrinone and postoperative pulmonary hypertension

Abstract

C LINICAL EXPERIENCE in both Europe and North America suggests that an increasing number of adult patients presenting for cardiac surgery are at risk of pulmonary hypertension. There are a number of factors responsible for this, not least the increasing age of the surgical patient population, and the fact that reoperation and cardiac surgery in very high risk cases are increasingly being undertaken. There is no doubt that the effective management of perioperative pulmonary hypertension remains a major challenge, but it should not be overlooked that optimizing the state of the pulmonary vasculature, and hence of right ventricular function, may have a significant beneficial effect in patients with not only borderline pulmonary hypertension but severe left ventricular impairment. In this situation right ventricular function may have a critical impact on left ventricular diastolic and systolic performance, and in this sense the treatment of the cardiac surgical patient should focus on more than simple pulmonary hemodynamics. Both physiologic and pharmacologic factors may have a major impact on the pulmonary vasculature. Many of the agents used in current practice are identified in this issue (see Dr Hines’ article). In the experimental setting, it is of course possible to strictly control many of the physiologic factors involved, but in clinical practice and research in humans, many of the factors may only be modified to a limited extent, and so the effectiveness of any drug therapy has to be viewed within the context of the clinical environment under study. In this article the experimental and clinical data currently published on the effects of milrinone on the pulmonary circulation are reviewed, with the aim of identifying any potential role of this important new compound in the management of postoperative pulmonary hypertension.