**4.3.2 Physical findings**

A clinical diagnosis of CoA is best made by simultaneous palpation of femoral and brachial pulses. The left ventricular impulse may be increased. A thrill is usually felt in the suprasternal notch. The first and second heart sounds are usually normal in isolated aortic coarctation. Since a large percentage (up to 60%) of patients with CoA have associated bicuspid aortic valves, an ejection systolic click may be heard at right upper and left mid sternal borders and apex; this click does not change with respiration. An ejection systolic murmur may be heard at left or right upper sternal borders, but is usually heard best over the back in the inter-scapular regions. Sometimes a continuous murmur may be heard in the left inter-scapular region secondary to continuous flow in the coarcted segment or on the back (secondary to flow in the collateral vessels). Palpation of the brachial and femoral artery pulses simultaneously will reveal delayed and decreased or absent femoral pulses. Blood pressure in both arms and one leg must be determined: a peak systolic pressure difference of more than 20 mmHg in favor of arms may be considered as evidence for coarctation of the aorta (Rao 1995). Involvement of the left subclavian artery in the coarctation or anomalous origin of the right subclavian artery (below the level of coarctation) may produce decreased or absent left or right brachial pulses, respectively, and therefore palpation of both brachial pulses and measurement of blood pressure in both arms are important.

#### **4.3.3 Noninvasive evaluation**

#### **4.3.3.1 Chest x-ray**

Chest roentgenogram may show a normal sized heart or the heart may be mildly enlarged. Other roentgenographic features include a "3" sign on a highly penetrated chest x-ray, inverted "3" sign of the barium filled esophagus and rib-notching (secondary to collateral vessels).

#### **4.3.3.2 Electrocardiogram**

The ECG may be normal or may show left ventricular hypertrophy.

Congenital Heart Defects – A Review 15

Fig. 7. Selected cine frames from aortic arch angiogram in 20-degree left anterior oblique projection demonstrating aortic coarctation with isthmic hypoplasia in an adolescent prior

Fig. 8. Bar graph showing immediate and follow-up results after balloon angioplasty of native aortic coarctation. Peak-to-peak systolic pressure gradients across the coarctation in mmHg (mean + SEM) are shown. Note significant (p 0.001) drop in the gradient following angioplasty (Pre, prior to vs. Post). The gradient increases (p 0.05) slightly at a mean follow-up of 14 mo. However, these values are lower (p 0.001) than those prior to

angioplasty. At late follow-up (LFU), (median 5 years) following balloon angioplasty, blood pressure-measured arm-leg peak pressure difference is lower than catheterization measured peak gradients prior to (p 0.001) balloon angioplasty and those obtained at intermediate-

When surgical option is chosen, resection and end-to-end anastomosis, subclavian flap angioplasty or prosthetic patch angioplasty may be used depending upon anatomy of the aortic arch and coarctation and surgeon's preference. When balloon angioplasty is contemplated, the balloon size should be carefully chosen: the diameter of the balloon

to (A) and immediately following (B) stent implantation.

term follow-up (p 0.01).

#### **4.3.3.3 Echocardiogram**

Echocardiographic studies usually reveal the coarctation in the supra-sternal notch, twodimensional echo views of the aortic arch. Increased Doppler flow velocity in the descending aorta by continuous-wave Doppler and demonstrable jump in velocity at the coarcted segment by pulsed-Doppler technique are usually present. Extension of the Doppler flow signal into the diastole is indicative of significant obstruction. Instantaneous peak pressure gradients across the aortic coarctation can be calculated by employing modified Bernoulli equation in manner similar to that described for PS and AS. Because of higher proximal velocity, coarctation gradients may be more accurately estimated by:

$$
\Delta \, \mathbf{P} = 4 \, (\mathbf{V}\_2^2 - \mathbf{V}\_1^2)
$$

Where, Δ P is peak instantaneous gradient and V2 and V1 are peak Doppler velocities in the descending aorta distal to the coarctation (continuous wave Doppler) and proximal to the coarctation (pulsed Doppler), respectively.

But the calculated gradient is usually an over-estimation, especially if there is no diastolic extension of the Doppler velocity (Rao and Carey 1989).
