Which defect is least likely to lead to irreversible pulmonary hypertension?

Which defect is least likely to lead to irreversible pulmonary hypertension?

• A. Persistent truncus arteriosus
• B. Tetralogy of Fallot
• C. Atrial septal defect
• D. Ventricular septal defect

Answer: (C)

Pulmonary vascular remodeling to an irreversible state (Eisenmenger syndrome) happens when the pulmonary circulation is exposed to sustained high flow and/or high pressures from a left-to-right shunt. The likelihood of this progression depends on how much and how long the pulmonary vessels are stressed by the defect. Persistent truncus arteriosus drives a high-volume, high-pressure flow into the pulmonary arteries from birth, so the pulmonary vasculature remodels early and the risk of irreversible pulmonary hypertension is high. A ventricular septal defect, especially when large, similarly creates substantial left-to-right flow into the lungs and can lead to progressive PHT if unrepaired. A PDA also launches a high-flow, high-pressure load to the pulmonary bed, promoting vascular remodeling and potential Eisenmenger physiology over time. Atrial septal defect generally causes chronic volume overload with relatively lower pulmonary pressures, so the pulmonary vessels are less subjected to the high-pressure stress that accelerates irreversible remodeling; thus progression to irreversible pulmonary hypertension is less likely compared with the other defects listed. Therefore, an atrial septal defect is the defect least likely to lead to irreversible pulmonary hypertension.

Pulmonary vascular remodeling to an irreversible state (Eisenmenger syndrome) happens when the pulmonary circulation is exposed to sustained high flow and/or high pressures from a left-to-right shunt. The likelihood of this progression depends on how much and how long the pulmonary vessels are stressed by the defect.

Persistent truncus arteriosus drives a high-volume, high-pressure flow into the pulmonary arteries from birth, so the pulmonary vasculature remodels early and the risk of irreversible pulmonary hypertension is high. A ventricular septal defect, especially when large, similarly creates substantial left-to-right flow into the lungs and can lead to progressive PHT if unrepaired. A PDA also launches a high-flow, high-pressure load to the pulmonary bed, promoting vascular remodeling and potential Eisenmenger physiology over time. Atrial septal defect generally causes chronic volume overload with relatively lower pulmonary pressures, so the pulmonary vessels are less subjected to the high-pressure stress that accelerates irreversible remodeling; thus progression to irreversible pulmonary hypertension is less likely compared with the other defects listed.

Therefore, an atrial septal defect is the defect least likely to lead to irreversible pulmonary hypertension.