Left-to-right cardiac shunt: perioperative anesthetic considerations.

Congenital heart disease (CHD) affects roughly 8/1000 live births. Improvements in medical and surgical management in recent decades have resulted in significantly more children with left-to-right cardiac shunts surviving into adulthood. Surgical care of these patients for their original cardiac defect(s) or other non-cardiac medical conditions requires thorough understanding of cardiopulmonary changes and mastery of treatment options. Commonly encountered CHD with left-to-right shunt include atrial septal defect (ASD), ventricular septal defect (VSD), endocardial cushion defect (ECD) and patent ductus arteriosus (PDA). The key pathological change is increased pulmonary vascular resistance (PVR) and pressure secondary to increased blood flow from the left-to-right shunt. Increasing PVR and pulmonary arterial hypertension (PAH) will lead to reversed direction of blood flow through the cardiac defect (Eisenmenger Syndrome) and heart failure. Cardiac defects with left-to-right shunt generally require surgical or trans-catheter repair at an early age. We review the current concepts and general principles of perioperative anesthetic management of CHD, including neuraxial anesthesia. Current techniques and unique pharmacodynamic and pharmacokinetic effects of some commonly used anesthetic agents in patients with left-to-right shunt are also reviewed.