Description

• Congenital defects involve the walls of the heart, its valves, arteries, and/or veins potentially or actually resulting in hemodynamic effects.
• ~40 different types
• Stratification: cyanotic or acyanotic versus complex, moderate, and simple
• The number of patients surviving into adulthood has increased with early detection, improved imaging modalities, new medications, surgical intervention methods, and management of comorbid conditions.
• Systems affected: cardiovascular, pulmonary, renal, hepatic, hematologic, integumentary

Epidemiology

Incidence

• 1% of births each year in the United States (1)
• ~40,000 live births each year (1:4 severe) (2)
• Most common cyanotic: tetralogy of Fallot
• Most common: bicuspid aortic valve (BAV): 1–2% of general population (2)
• ACHD other than BAV: atrial septal defect (ASD) 30–40% and solitary ventricular septal defect (VSD) 15–20% (2)

Prevalence

• AHA: 1.3 million people alive in 2015 have a congenital heart defect (3).
• Mild: 45%, moderate: 37%, severe: 14% (2)

Etiology and Pathophysiology

• Most are unknown; multifactorial
• ACHDs are a myriad of anatomical malformations of the cardiovascular system during fetal development that lead to physiologic and anatomic dysfunction.
• Causes: persistent or absent pharyngeal arch artery derivatives, aberrant heart tube fusion, endocardial cushion formation, muscular and membranous septal migration and changes, and neural crest cell induction of differentiation
• Left to right versus right to left shunting

Genetics
Associated congenital syndromes: Down, 22q11.2 deletions (i.e., DiGeorge, velocardiofacial, conotruncal anomaly face), Williams-Beuren, Turners, Holt-Oram, Noonan, Alagille, Marfan, Ehlers-Danlos, Osler-Weber-Rendu, Jervell and Lange-Nielsen, Romano-Ward, VACTERL, osteogenesis imperfecta, familial ASD

Risk Factors

Family history, consanguinity, prenatal exposure to obesity, smoking, EtOH, thalidomide, ACEI/ARBs

General Prevention

• Genetic counseling/testing prior to conception for patients with known ACHD
• Prevention of gestational diabetes; controlling maternal SLE; maternal rubella immunization; avoid exposures to EtOH, amiodarone, thalidomide, and other category X medications.
• Most cases are de novo with cause unknown.

Commonly Associated Conditions

• Systolic and diastolic congestive heart failure (CHF)
• Wolff-Parkinson-White (WPW) syndrome
  • Atrial enlargement/scar → atrial fibrillation and atrial flutter
• SA node dysfunction, especially if prior surgical correction/palliation was attempted
• IART
• Cyanotic CHD: hypoxemia, hyperviscosity syndrome, and erythrocytosis
• Protein-losing enteropathy
• Renal failure and chronic kidney disease (CKD): gout, anemia, and hyperuricemia
• Gallstones due to increased Ca⁺+ bilirubinate
• Stroke/brain abscess: microcytosis and paradoxical cerebral emboli
• Pulmonary arterial hypertension (PAH)—Eisenmenger syndrome (ES) (intracardiac communication with pulmonary hypertension, reversal of flow [right to left], and cyanosis)
• Scoliosis/kyphosis from prior surgeries