Aortic Coarctation

1- General:

A- isthmic coarctation or aortic stenosis is a narrowing seated on the isthmus at the junction of the aortic arch and descending aorta downstream of the location of the left sub clavian, at arterial ligament.

B- relatively common disorder Net male. 4 times more common in men.

This may be a genetic heart disease: it is common in the context polymalformative Turner syndrome (45, X0).

Frequently associated with other congenital heart defects (patent ductus arteriosus, VSD, aortic or mitral valve abnormality).

C- Pathophysiology:

The three pathophysiological syndromes coarctation are:

* The pressure upstream of the obstacle, and therefore the upper body,

* Hypotension downstream of the coarctation, therefore in the lower half of the body.

* Development of collateral circulation bypassing the obstacle, allowing blood of the above-strictural segment to win the sub-segment strictural by circuitous routes;anastomoses are essentially made up of branches of subclavian:

* Periscapular network (between subclavian and 4th, 5th, and 6th intercostal)

* Network intercostal (between anterior intercostal branches arising from the internal mammary and intercostal later joined by which the aortic blood against the current)

* Internal mammary-epigastric anastomoses,

* Intraspinal anastomoses between the Anterior spinal and vertebral artery.

These anastomotic arteries are large, sinuous and erode the bottom edge of the posterior costal arches.

2- Clinic:

Type description: the shape of the great child or adolescent.

A- Clinical signs:

The association of hypertension MS and a decrease or elimination of femoral pulse is almost pathognomonic of coarctation.

– MV of the upper half of the body, systolic-diastolic highly variable degree. It is accompanied by a hyperpulsatilité arteries MS and neck vessels, especially lifting of the aortic arch at the suprasternal hollow.

Sometimes functional signs associated with hypertension headache, tinnitus, epistaxis …

Complications of hypertension are possible, especially brain (subarachnoid hemorrhage, brain edema …).

Sometimes there is a mismatch between the 2MS blood pressure linked to the implementation of the sub left subclavian at the coarctation.

– The hypo-vascular syndrome MI contrast to this HTA MS:

* Tiredness or cramping in the effort MI

* Sometimes contrast between the morphology of the upper body, squat and robust and that of the lower half, with MI slender.

– Absence of femoral pulses with TA much lower than the MI MS (MS-MI gradient> 20 mmHg).

* Discreet systolic murmur, spreading throughout the thorax, max. 3rd EICG heard in the back; sometimes systolodiastolique breath due to collateral circulation.

* Collateral Circulation, highlighted in oblique light, the patient bent forward, as systolic uprisings intercostal spaces or beats on palpation.

B- Radiography:

Sometimes picture “chimney” of the upper mediastinum, with disappearance of the aortic knob; expansion or pre- or post-stricturale visible at the upper left arc; typically same, the image “3” of figure: Double aortic knee with an indentation between the upper protrusion of the lower.

LVH (left ventricular hypertrophy) possible.

Costal notches (due to bone erosion by large intercostal arteries).

C- ECG:

HVG possible.

D- specialized tests:

Doppler echocardiogram: often used to display the coarctation and to measure the pressure gradient across the stenotic area: it specifies the reaction LVH and the existence of associated anomalies.

The thoracic aortic pathology is an excellent indication of the examination by magnetic resonance imaging (MRI).Currently, intervention is often made on the data of Doppler ultrasound and MRI, without angiography.

Angiography: Indirect (time left a straight angio infant or digital angiography) or direct: arterial retrograde aortography; it confirms the diagnosis and precise anatomical conditions: In most cases, short stenosis, diaphragm significantly reducing aortic lumen.

Sometimes extended hypoplasia of the isthmus, common in infants. Angiography highlights the collateral circulation and the level of implementation of the large vessels of the base.

3- Evolution – Complications:

HTA, with its complications, which may persist after surgery if it is too late hence the importance of early detection and surgical treatment.

Rupture or aortic dissection.

Cerebral complications (bleeding, aneurysms, hemiplegia).
IVG.

Infective endocarditis.

Without intervention, death usually occurs before age 40 in the forms tight.

4- Clinical forms:

Severe form of newborn and infant.

Table of severe asystole, early (first few days or weeks of life), sometimes dramatically during closure of the ductus arteriosus.

It is usually in the case of a tight coarctation, associated with a sub-strictural ductus arteriosus (in fact, in this case, the fetal circulation has been done normally and no collateral circulation is not developed, so that in case of the above-strictural canal collateral circulation developed during fetal life and tolerance at birth is much better). Common association of VIC.

The diagnosis is made on ultrasound. Turning prostaglandin E1 keeps open CA and significantly improves the state.Urgent indication for surgery without prior catheterization.

5- Treatment:

Any symptomatic coarctation must be made.

Most often, the intervention of Crafoord (resection of the coarctation area with anastomosis butt) is possible.

Importance of early detection (systematic palpation of femoral children) in order to operate early, ideally before the age of 4 years, to avoid residual hypertension .