Parenteral Phenoxybenzamine During Congenital Heart Disease Surgery

• Status: Withdrawn
• Trial end date: 2010-08-01
• Target enrollment: 0
• Participant gender: All

Summary

Phenoxybenzamine, an irreversible alpha-adrenergic blocker, may prove beneficial to infants and children with congenital heart disease undergoing open cardiac repair, due to a theoretic benefits of a uniform and smooth reduction in systemic vascular resistance in the perioperative period. Vasodilation allows for low pressure, high flow systemic perfusion while on cardiopulmonary bypass. Support for the use of phenoxybenzamine in humans has been documented in several studies involving the perioperative management of both adults and children requiring cardiopulmonary bypass, and in management of patients with pheochromocytoma. 1-7 Phenoxybenzamine has been associated with more uniform body cooling and rewarming, and improved tissue perfusion during bypass.8 It is also known to increase cardiac output, stroke volume, and renal blood flow when given intravenously. 9 Specifically in pediatric open heart surgery, the combined use of phenoxybenzamine and dopamine provided a stable hemodynamic condition without a high total peripheral vascular resistance and stimulated postoperative diuresis. 9 Afterload reduction with parenteral phenoxybenzamine in neonates undergoing the Norwood procedure for hypoplastic left heart syndrome is associated with improved systemic oxygen delivery and stabilization of systemic vascular resistance.10 Furthermore, a strategy of reducing afterload with phenoxybenzamine and stabilizing the pulmonary to systemic flow ratio in this select population of patients has also been shown to improve operative survival. 11 We hypothesize that phenoxybenzamine will reduce afterload on the systemic ventricle in our selected patient population, thereby improving ventricular performance and decreasing the risks of pulmonary to systemic flow imbalance associated with current short-acting vasodilator therapy. We will plan to evaluate both physiologic variables as well as surgical outcomes in the selected study population.

• Phase: Phase 2
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Vanderbilt University; Vanderbilt University Medical Center
• Treatments: Phenoxybenzamine

Criteria

Patient selection will be determined by an assessment of the risk of systemic ventricular dysfunction following open cardiac repair in a population of infants undergoing stage I palliation (Norwood procedure) for the diagnosis of either hypoplastic left heart syndrome or similar left-sided obstructive lesions in the setting of single-ventricle physiology. Eligible neonates and infants include those aged 0 days to 6 months. These patients will be evaluated on an individual basis and the decision to give phenoxybenzamine would be determined by the attending surgeon, anesthesiologist, and cardiologist.