Aortic coarctation is a focal narrowing of the aorta, typically at the level of the ligamentum arteriosum (distal to the left subclavian artery). It is one of the most common congenital aortic malformations, comprising 5-8% of all congenital heart diseases. The adult type presents with upper extremity hypertension, weak lower extremity pulses, and femoral pulse delay. CTA/MRA is the gold standard for diagnosis; chest radiograph shows the classic 3-sign, rib notching, and reverse 3 sign. Association with bicuspid aortic valve (50-85%) and Turner syndrome (15-25%). Without treatment, it can cause early death (median survival 31 years). Treatment options include surgical repair or balloon angioplasty/stent.
Age Range
0-50
Peak Age
20
Gender
Male predominant
Prevalence
Uncommon
The pathogenesis of aortic coarctation is based on aberrant migration of ductus arteriosus tissue into the aortic wall. As the ductus arteriosus closes, the contracting ductal tissue incorporates the aortic wall, creating focal narrowing — this is most prominent at the isthmus because this is the ductal insertion point. Pressure increases proximal to the narrowed segment (upper extremity hypertension) and decreases distally (lower extremity hypoperfusion). In response to the chronic pressure gradient, collateral pathways develop: most importantly through the internal mammary artery to intercostal arteries and then anastomosis to the aorta distal to the coarctation. Dilated intercostal arteries erode the inferior rib margins — appearing as rib notching on chest radiograph; typically bilateral and symmetric at ribs 3-8 and absent at the first two ribs (because the 1st-2nd intercostal arteries arise from the costocervical trunk). CTA shows the narrow segment, prestenotic dilatation, and poststenotic dilatation — these three components form the 3-sign on chest radiograph.
On chest radiograph/CTA, prestenotic dilatation + coarctation notch + poststenotic dilatation in the aortic contour resembles the number 3. Accompanying erosion of inferior rib margins at ribs 3-8 is due to dilated intercostal collateral arteries. A reverse 3 (E-sign) can also be seen on barium swallow.
CTA arterial phase demonstrates focal aortic narrowing at the level of the ligamentum arteriosum. The coarctation segment diameter may decrease to less than 50% of normal aortic diameter. Proximal dilatation at the left subclavian artery origin (prestenotic) and distal poststenotic dilatation are seen. 3D VRT and multiplanar reformats best demonstrate the degree, length, and morphology of stenosis. Sagittal oblique reformat optimally images the left aortic arch and isthmus region.
Report Sentence
CTA demonstrates focal aortic narrowing at the isthmus distal to the left subclavian artery origin with coarctation segment diameter of __ mm.
CTA demonstrates markedly dilated collateral vessels: internal mammary arteries (retrosternal), intercostal arteries (paravertebral), scapular rete, lateral thoracic arteries, and inferior epigastric arteries. These collaterals bypass the coarctation segment, carrying blood from the high-pressure upper extremity to the lower extremity. On 3D VRT, described as basket-weave pattern. MIP images best demonstrate small collateral branches.
Report Sentence
Markedly dilated collateral vessels bypassing the coarctation segment are noted, with prominent internal mammary and intercostal arteries.
Non-contrast CT or chest radiograph demonstrates bilateral symmetric notching of the inferior margins of ribs 3-8. Chronic pulsatile compression from dilated intercostal arteries erodes the rib cortex. Absent at the first two ribs because intercostal arteries at this level arise from the costocervical trunk. Unilateral rib notching may be seen with aberrant right subclavian artery or left subclavian artery occlusion.
Report Sentence
Bilateral notching of the inferior margins of ribs 3-8 is noted, suggesting dilated intercostal collateral flow secondary to chronic aortic coarctation.
Gadolinium-enhanced MRA demonstrates focal narrowing at the aortic isthmus with high contrast resolution. CE-MRA is preferred in young patients and follow-up due to absence of radiation. 4D flow MRI non-invasively measures flow velocity, pressure gradient, and wall shear stress across the coarctation segment. Phase-contrast MR can calculate peak velocity and pressure gradient (modified Bernoulli equation: dP = 4V2). Ideal for post-repair follow-up to assess re-coarctation, aneurysm, or stent stenosis.
Report Sentence
MRA demonstrates focal narrowing at the aortic isthmus with minimum coarctation segment diameter of __ mm and calculated pressure gradient of __ mmHg.
Doppler US from the suprasternal window demonstrates high-velocity jet flow at the aortic isthmus. Spectral Doppler shows peak systolic velocity >2.5 m/s at the coarctation segment with continuous diastolic flow (diastolic tail). Abdominal aorta Doppler shows parvus-tardus waveform. In neonates, arch and isthmus assessment can be performed from the subcostal window. Accompanying bicuspid aortic valve is investigated by echocardiography.
Report Sentence
Peak systolic velocity of __ m/s measured at the aortic isthmus from the suprasternal window with continuous diastolic flow; calculated pressure gradient __ mmHg.
Bicuspid aortic valve accompanies 50-85% of coarctation patients. On ECG-gated CT, valve morphology is evaluated on axial and oblique images — two leaflets (fish-mouth orifice) are seen in systole. Aortic root dilatation and ascending aortic aneurysm may accompany. Cranial MRA should also be evaluated due to associated Berry aneurysm risk (3-10%).
Report Sentence
Bicuspid aortic valve accompanying aortic coarctation is identified with aortic root diameter measuring __ mm.
Criteria
Narrowing proximal to ductus arteriosus, long segment, severe obstruction, symptomatic in neonatal period
Distinct Features
Ductus-dependent systemic circulation, prostaglandin E1 treatment required, may coexist with hypoplastic arch, other congenital anomalies common (VSD, ASD, bicuspid valve)
Criteria
Narrowing distal to or at the level of ductus arteriosus, focal discrete stenosis, compensated by collateral development
Distinct Features
May be diagnosed in adulthood, upper-lower extremity pressure difference, rib notching, 3-sign, bicuspid valve association 50-85%, Berry aneurysm risk 3-10%
Criteria
Buckling/kinking at the aortic isthmus without hemodynamically significant stenosis; pressure gradient <20 mmHg
Distinct Features
No rib notching (no collateral development), no or minimal upper-lower extremity pressure difference, no treatment needed
Criteria
Recurrent narrowing at previous repair site; pressure gradient >20 mmHg
Distinct Features
Stenting is first-line treatment, serial MRA/CTA follow-up needed, aneurysm development at repair site may also be seen
Distinguishing Feature
Takayasu shows multifocal vessel involvement (aorta + branches), wall thickening and enhancement, in young women; coarctation is focal isthmus narrowing without wall thickening
Distinguishing Feature
Dissection shows intimal flap and dual lumen, acute onset pain; coarctation shows focal narrowing, no flap, chronic course
Distinguishing Feature
IMH shows hyperdense wall thickening and wall hematoma; coarctation has lumen narrowing + collateral development, no wall hematoma
Distinguishing Feature
Leriche shows infrarenal aortic occlusion (atherosclerotic, elderly patient); coarctation is congenital narrowing at isthmus (young patient, congenital heart disease associations)
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
annualTreatment options: surgical repair (resection + end-to-end anastomosis or patch) or balloon angioplasty with stent (native or re-coarctation). In neonatal coarctation, prostaglandin E1 maintains ductus patency for urgent intervention. Treatment indication: upper-lower extremity pressure gradient >20 mmHg or severe structural stenosis. Lifelong follow-up required post-treatment: re-coarctation (5-10%), aneurysm formation, residual hypertension (30-50% in adult repair). Turner syndrome and bicuspid valve screening should be performed.
Severe aortic coarctation can cause heart failure in infancy; mild forms present with hypertension in adulthood. Treatment is surgical (resection + end-to-end anastomosis) or endovascular (balloon angioplasty with or without stent). Lifelong follow-up is required after repair due to risk of recoarctation, aneurysm, and persistent hypertension. Berry aneurysm risk is increased.