Overview
The Pressure Split Created by Coarctation
Coarctation of the aorta is a fixed narrowing that separates the circulation into a high pressure region above the obstruction and a low flow region below it.
Coarctation of the aorta is a fixed narrowing that separates the circulation into a high-pressure region above the obstruction and a low-flow region below it. The result is not simply a high blood pressure reading: the left ventricle must generate greater pressure to eject blood, while the kidneys, abdominal organs, and legs may receive reduced perfusion. In a newborn, the ductus arteriosus can temporarily bypass the narrowed segment. When the ductus constricts, distal systemic flow may fall abruptly and cardiogenic shock can develop. In an older child or adult, intercostal and other collateral vessels may enlarge gradually and preserve leg perfusion. Those collaterals help the patient compensate, but they can also make the measured gradient appear deceptively mild. The bedside pattern is therefore more informative than any single symptom: compare arm and leg pressures, feel the femoral pulses, and ask whether the patient has an associated left-sided cardiac lesion or a history of repair. Anatomical correction does not end the disease process; hypertension, aortic wall disease, recoarctation, aneurysm, and associated valve disease require lifelong surveillance.