aortic coarctation

Aortic coarctation is classified into infantile (preductal) and adult (postductal/juxtaductal) types. The infantile type is associated with patent ductus arteriosus (PDA) and presents in neonates with lower extremity cyanosis and heart failure, as blood flow to the lower body depends on the PDA (ductal-dependent circulation). The adult type is typically juxtaductal, occurring near the closed ligamentum arteriosum, and often presents later in life with hypertension in the upper extremities and diminished/delayed pulses in the lower extremities. Collateral circulation develops through the intercostal arteries, leading to notching of the ribs visible on chest X-ray, and a classic 'figure 3 sign' on CXR or 'reverse 3 sign' on barium swallow. Patients may have a systolic ejection murmur, best heard over the back, and can develop left ventricular hypertrophy due to increased afterload. Associations include bicuspid aortic valve (leading to increased risk of aortic dissection/rupture), Turner syndrome, and berry aneurysms in the circle of Willis (risk of subarachnoid hemorrhage). Diagnosis involves blood pressure discrepancy between upper and lower extremities, imaging (echocardiography, CT/MRI angiography), and can be confirmed via cardiac catheterization. Treatment includes surgical resection with end-to-end anastomosis or balloon angioplasty with stenting, especially in older children/adults. Long-term complications, even after repair, include persistent hypertension, aortic aneurysm, and increased cardiovascular risk, so lifelong follow-up is required.