Parenteral Phenoxybenzamine During Congenital Heart Disease Surgery
Status:
Withdrawn
Trial end date:
2010-08-01
Target enrollment:
Participant gender:
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
Details
Lead Sponsor:
Vanderbilt University Vanderbilt University Medical Center