INSTRUCTION

Examine this patient's cardiovascular system.

SALIENT FEATURES

History

· Usually asymptomatic.

Symptoms are usually those of hypertension: headache, epistaxis, dizziness, and palpitations.

Claudication (due to diminished blood flow to the legs).

Occasionally, diminished blood flow to the legs can cause leg fatigue.

· Patients sometime seek mertical attention because they have symptoms of heart failure or aortic

dissection. Women with coarctation are at particularly high risk for aortic dissection during pregnancy.

Examination

· The upper torso is better developed than the lower part.

· The systolic arterial pressure is higher in the arms than in the legs, but the diastolic pressures are

similar, therefore a widened pulse pressure is present in the arms. (Note. This condition results in

hypertension in the arms. Less commonly, the coarctation is immediately proximal to the left subclavian

artery, in which case a difference in arterial pressure is noted between the arms.)

· Radial pulse on the left side may be less prominent.

· The femoral arterial pulses are weak and delayed (simultaneous palpation of the brachial and femoral

arteries using the thumbs is the most convenient method of comparing pulsations in the upper and lower

limbs).

· A systolic thrill may be palpable in the suprasternal notch.

· Heaving apex due to left ventricular enlargement.

· A systolic ejection click (due to a bicuspid aortic valve which occurs in 50% of cases) is frequently

present, and the second heart sound is accentuated.

· A harsh systolic ejection murmur may be identified along the left sternal border and in the back,

particularly over the coarctation.

· Scapular collaterals are visible (listen over these collaterals for murmur).

· A systolic murmur, caused by flow through collateral vessels, may be heard in the back.

· In about 30% of patients with aortic coarctation, a systolic murmur indicating an associated bicuspid

aortic valve is audible at the base.

Look for:

· Turner's syndrome (female, webbing of the neck, increased carrying angle).

· Berry aneurysms (extraocular movements impaired due to third cranial nerve involvement).

DIAGNOSIS

This patient has coarctation of the aorta (lesion) with left ventricular failure (functional status).

ADVANCED-LEVEL QUESTIONS

What are the types of aortic coarctation?

Common:

· Infantile or preductal where the aorta between the left subclavian artery and patent ductus arteriosus is

narrowed. It manifests in infancy with heart failure. Associated lesions include patent ductus arteriosus,

aortic arch anomalies, transposition of the great arteries, ventricular septal defect.

· Adult type: the coarctation in the descending aorta is juxtaductal or slightly postductal. It may be

associated with biscuspid aortic valve or patent ductus arteriosus. It commonly presents between the

ages of 15 and 30 years.

Rare:

· Localized juxtaductal coarctation.

· Coarctation of the ascending thoracic aort

· Coarctation of the distal descending thoracic aorta.

· Coarctation of the abdominal aorta.

· Pseudocoarctation is of no haemodynamic significance and is a 'kinked' appear-ance of the aorta in the

juxtaductal region without stenosis.

Is aortic coarctation more common in men or women?

This condition is two to five times as frequent in men and boys as in women and girls.

What conditions are associated with coarctation of aorta?

It may occur in conjunction with gonadal dysgenesis (e.g. Turner's syndrome), bicuspid aortic valve,

ventricular septal defect, patent ductus arteriosus, mitral stenosis or regurgitation, or aneurysms of the

circle of Willis.

At what age does the condition manifest?

It is particularly likely to produce significant symptoms in early infancy (presenting

as cardiac failure) or between the ages of 20 and 30 years.

How would you investigate this patient?

· Electrocardiogram: usually shows left ventricular hypertrophy.

· Chest radiograph: symmetric rib notching. The coarctation may be visualized as the characteristic '3'

sign on a chest radiograph (or a reverse '3' sign on the barium swallow). The upper bulge is formed

by dilatation of the left subclavian artery high on the left mediastinal border, the sharp indentation is

the site of the coarctation, and the lower bulge is called the poststenotic dilatation of the aorta.

· Echocardiogram: the coarctation may be visualized echocardiographically, and Doppler examination

makes possible an estimate of the transcoarctation pressure gradient.

· Computed tomography, magnetic resonance imaging and contrast aortography are useful to

determine the precise anatomy regarding the location and length of the coarctation; in addition,

aortography permits visualization of the collateral circulation.

What causes rib notching?

Collateral flow through dilated, tortuous and pulsatile posterior intercostal arteries typically causes

notching on the undersurfaces of the posterior portions of the ribs. The anterior parts of the ribs are

spared because the anterior intercostal arteries do not run in the costal grooves. Notching is seldom

found above the third or below the ninth rib and rarely appears before the age of 6 years.

Mention a few conditions in which rib notching is seen.

· Coarctation of aorta.

· Pulmonary oligaemia.

· Blalock-Taussig shunt.

· Subclavian artery obstruction.

· Superior vena caval syndrome.

· Neurofibromatosis.

· Arteriovenous malformations of the lung or chest wall.

What are the complications of aortic coarctation?

· ·Severe hypertension and resulting complications:

· Stroke.

· -Premature coronary artery disease.

· Left ventricular failure (two thirds of patients over the age of 40 years who have

· uncorrected aortic coarctatioh have symptoms of heart failure).

· Rupture of aorta.

· Infective endocarditis endarteritis (at the site of the coarctation or on a con-genitally bicuspid

aortic valve).

· Intracranial haemorrhage (combination of hypertension and ruptured berry aneurysm).

· Three quarters die by the age of 50, and 90% by the age of 60 (Bt Heart J 1970: 32: 63340).

What are the fundal findings in coarctation of aorta?

Hypertension due to coarctation of aorta causes retinal arteries to be tortuous with frequent 'U' turns;

curiously, the classical signs of hypertensive retinopathy are rarely seen.

What is the treatment of such patients?

· Surgical repair should be considered for patients with a transcoarctation pressure gradient of more than

30 mmHg. Although balloon dilatation is a therapeutic alternative, the procedure is associated with a

higher incidence of subsequent aortic aneurysm and recurrent coarctation than surgical repair

(Circulation 1993: 87: 793-9).

· Surgical resection and end-to-end anastomosis, although a tubular graft may be required if the narrowed

segment is too long.

What are the postoperative complications?

Postoperative complications include recurrent coarctation, persistent hypertension and the possible

sequelae of a bicuspid aortic valve.

What happens to the hypertension after surgery?

Despite surgery, some patients may continue to have residual or recurrent hyper-tension and will require

monitoring for hypertension and premature coronary artery disease (Circulation 1989; 80: 840-5). The

incidence of persistent or recurrent hypertension is influenced by the patient's age at the time of surgery:

Among patients who undergo surgery during childhood, 90% are normotensive 5 years later, 50% are

normotensive 20 years later, and 25% are normotensive 25 years later.

Among those who undergo surgery after the age of 40 years, half have persistent hypertension, and

many of those with a normal resting blood pressure after successful repair have a hypertensive response

to exercise.

Is survival improved by surgery?

Survival after repair of aortic coarctation is influenced by the age of the patient at the time of surgery:

After surgical repair during childhood, 89% of patients are alive 15 years later and 83% are alive 25

years later.

When repair of coarctation is performed when the patient is between the ages of 20 and 40 years, the

25-year survival is 75%.

When repair is performed in patients more than 40 years old, the 15-year survival is only 50%.