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Summary

Types of congenital cardiac disease: acyanotic — "pink babies;” there is pressure or volume overload of an area of the heart; anomalies include patent ductus arteriosus, atrial septal defect (ASD), ventricular septal defect (VSD), and coarctation of the aorta; cyanotic — “blue babies;” anomalies include tetralogy of Fallot, transposition of the great arteries, tricuspid atresia, total anomalous pulmonary venous return, truncus arteriosus, hypoplastic left heart, and pulmonary atresia; acyanotic defects are more common; VSD and ASD may be detected later in life when patients develop symptoms related to a long duration shunt; heart failure symptoms are most common

Fetal circulation: umbilical arteries carry deoxygenated blood to the placenta; the umbilical vein carries oxygenated blood from the placenta through the ductus venosus, bypassing the liver; blood then goes to the right atrium (RA) and across the ASD into the left atrium (LA); it then flows into the left ventricle (LV) and through the aorta; pulmonary vascular resistance (PVR) is very high and prevents blood flow from the right ventricle (RV); the blood that does flow into the RV goes up the pulmonary artery (PA), crosses the ductus arteriosus into the aorta, and then to the rest of the systemic circulation; blood flows through the path of least resistance

Bicuspid aortic valve: this is the most common defect; it is usually detected later in life when patients present with signs or symptoms of heart failure or aortic stenosis; murmurs may lead to early detection; the malformed valve has a higher resistance to flow and higher velocities of flow across it, leading to thickening, potential calcification, stenosis, and regurgitant backflow; stress on the aortic root can cause aortic root or thoracic aneurysms leading to coronary compromise; systemic vascular resistance (SVR) should not be reduced during anesthesia

Atrial septal defect: the second most common congenital cardiac defect; types include patent foramen ovale, secundum defect, sinus venosus defect, common atrium (usually associated with other congenital cardiac anomalies), and unroofed coronary sinus; the different types produce similar physiology over time; excessive pulmonary circulation is caused by blood flowing from the LA to the lower resistance in the RA; a higher percentage of blood flows to the lungs than the systemic circulation (Qp/Qs >1), leading to RA and RV overload; over time, resistance in the pulmonary circulation increases by stiffening the vessels and increasing the PVR, leading to pulmonary hypertension (HTN) and back pressure on the RV, eventually producing RV failure; ASD physiology worsens with increased SVR or reduced PVR; patients with left-to-right shunting tolerate anesthesia better than right-to-left; flow reverses to right-to-left as the disease progresses; with right-to-left flow, there is an increased risk for air embolism to the brain

Ventricular septal defect: physiology is similar to ASD; blood flows from the LV, across the VSD, and to the RV, causing excessive pulmonary circulation and volume overload on the right side of the heart; PVR increases, leading to pulmonary HTN and RV hypertrophy over time; progression tends to occur more rapidly in a VSD because the pressures are higher; VSDs are more frequently associated with arrhythmias

Tetralogy of Fallot: components include VSD, pulmonary stenosis, overriding aorta, and RV hypertrophy; if the aorta and aortic valve override the VSD by >50%, tetralogy of Fallot transitions to double outlet RV

Transposition of the great arteries: during the embryologic development of the truncus arteriosus, the spiraling septum that splits the PA and aorta develops straight; as a result, the aorta is on the right side and the PA is on the left side, leading to 2 separate circulatory systems which cannot sustain life without persistent fetal shunts; usually an ASD remains open and the ductus arteriosus remain patent; atrial septostomy is done in the absence of shunts; arterial switch surgery is performed within 1 wk of birth

Hypoplastic left heart syndrome: there is embryologic restriction of flow from the left side of the heart; repair is conducted in multiple stages; the first stage, called the Norwood procedure, is done within 1 wk of birth; the aorta is combined to the PA and a shunt to the pulmonary circulation is created; within 3 to 6 mo after birth, the Glenn operation is performed, where the superior vena cava (SVC) is joined to the pulmonary circulation, and the extra shunt is removed; the Fontan procedure is performed ≈18 mo after birth; an extracardiac conduit is created that provides passive blood flow from the inferior vena cava and the SVC to the pulmonary circulation, then into the LA and the rest of the circulation

Preanesthetic assessment: includes assessment of the original cardiac lesion, repairs performed, the current anatomy, functional status of the heart, and signs of failure; moderate- to high-risk lesions should be treated at a center familiar with congenital heart disease if possible; high-risk lesions include cyanotic heart disease, severe pulmonary hypertension, prior Fontan, ejection fraction <35%, severe left heart obstruction, Williams Syndrome, complex ventricular dysrhythmias, or Eisenmenger syndrome; lesions of moderate risk include prosthetic cardiac valves, any type of conduit, intracardiac shunt, moderate systemic ventricular dysfunction, moderate left sided heart obstruction, and moderate pulmonary hypertension; for patients at high to moderate risk who present for an urgent procedure, providers can be contacted to provide input to help improve outcomes; a multidisciplinary approach can improve outcomes

Cardiology clearance: acyanotic lesions that have no limitations (eg, ASD, repaired VSD) do not need regular cardiology follow up; poorly compensated acyanotic and cyanotic lesions should have seen their cardiologist within the last 6 mo; cyanotic lesions without limitations should visit their cardiologists every year

Other considerations: many patients with congenital heart defects have erythrocytosis and elevated hematocrit to compensate for low oxygen saturations of ≈75% to 85%; fasting for >8 hr can result in hyper viscous blood and propensity for clot formation; patients with extracardiac shunts or prosthetic valves are at risk for creating emboli or forming clots in their shunts; anticoagulant therapy, airway abnormalities, neurologic abnormalities, cognitive abnormalities, emotional abnormalities, and tolerance to opioids must be considered; surgery should be scheduled early in the day to ensure adequate availability of personnel; all regular medications should be continued unless directed otherwise by the patient’s cardiologist; neuraxial anesthesia should be administered slowly; a rapid sympathectomy can be catastrophic; some patients may tolerate a bolus of fluids, but others may not; colloids are preferred in cyanotic patients; ensure availability of vasoactive medications; patients may not tolerate decreases in preload that can be caused by increases in intrathoracic pressure; maintain low intrathoracic pressure, low tidal volumes, and low positive end-expiratory pressure; ensure adequate ventilation and oxygenation during emergence to avoid increases in PVR; avoid oversedation; postoperative pain and anxiety must be managed