LEFT-TO-RIGHT SHUNTS

• 40% of CHD cases

• higher left-sided pressures cause a shunt

• common lesions

  • atrial septal defect (ASD)

  • ventricular septal defect (VSD)

  • patent ductus arteriosus (PDA)

• uncommon lesion

  • aortopulmonary window—just above the pulmonary and aortic valves, the pulmonary artery and aorta touch each other, and there is a connection. very uncommon

• acyanotic until shunt reverses from L  R to R  L

• initially, though, increased right ventricular oxygen saturation and pressure. this is how they are diagnosed (via cath)

• increased pulmonary artery blood flow

• we must protect the pulmonary circulation—it tolerates large flow volumes, but not increased pressure

• if high pressure persists, microvasculature of lung will become irreparably damaged

Category: Pathology Notes