**4.3.4 Catheterization and angiography**

In isolated aortic coarctation, elevation of left ventricular and ascending aortic peak systolic pressure with significant peak-to-peak systolic pressure gradient across the coarctation is found. Selective aortic root or aortic arch angiography is necessary to clearly demonstrate the aortic narrowing.

### **4.3.5 Management**

Significant hypertension and/or congestive heart failure are indications for intervention. In the presence of congestive heart failure, conventional anti-congestive measures including digitalis and diuretics should be promptly instituted. In the presence of hypertension, it is better to relieve the obstruction promptly rather than attempting to "treat" hypertension with antihypertensive drugs. Aortic coarctation may be relieved either by surgery or by balloon angioplasty. Symptomatic children should undergo relief of coarctation soon after the child is stabilized. Asymptomatic children should undergo the procedure electively. If neither hypertension nor heart failure is present, elective relief of the obstruction between the ages of 2 and 5 years is suggested. Waiting beyond 5 years is not advisable because of evidence for residual hypertension if the aortic obstruction is not relieved by the age of 5 years.

Surgical relief of aortic coarctation is the conventional treatment option. Since the description balloon angioplasty in 1983, increasing number of cardiologists, including our group, have used this technique for relief of aortic coarctation (Rao 1989c; Rao et al 1996). While I believe that balloon angioplasty is the treatment option of choice for relief of native aortic coarctation, because of concern for development of aneurysms, some cardiologists prefer surgery. Balloon angioplasty may be an effective alternative to surgery for the relief of aortic coarctation. Children older than 1 year and adults with discrete native coarctation are candidates for balloon dilatation. Long-segment coarctations or those associated with significant isthmic hypoplasia may be candidates for stent placement, especially in adolescents and adults (Figure 7).

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:

Δ P = 4 (V22 – V12) 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

But the calculated gradient is usually an over-estimation, especially if there is no diastolic

In isolated aortic coarctation, elevation of left ventricular and ascending aortic peak systolic pressure with significant peak-to-peak systolic pressure gradient across the coarctation is found. Selective aortic root or aortic arch angiography is necessary to clearly demonstrate

Significant hypertension and/or congestive heart failure are indications for intervention. In the presence of congestive heart failure, conventional anti-congestive measures including digitalis and diuretics should be promptly instituted. In the presence of hypertension, it is better to relieve the obstruction promptly rather than attempting to "treat" hypertension with antihypertensive drugs. Aortic coarctation may be relieved either by surgery or by balloon angioplasty. Symptomatic children should undergo relief of coarctation soon after the child is stabilized. Asymptomatic children should undergo the procedure electively. If neither hypertension nor heart failure is present, elective relief of the obstruction between the ages of 2 and 5 years is suggested. Waiting beyond 5 years is not advisable because of evidence for residual hypertension if the aortic obstruction is not relieved by the age of 5

Surgical relief of aortic coarctation is the conventional treatment option. Since the description balloon angioplasty in 1983, increasing number of cardiologists, including our group, have used this technique for relief of aortic coarctation (Rao 1989c; Rao et al 1996). While I believe that balloon angioplasty is the treatment option of choice for relief of native aortic coarctation, because of concern for development of aneurysms, some cardiologists prefer surgery. Balloon angioplasty may be an effective alternative to surgery for the relief of aortic coarctation. Children older than 1 year and adults with discrete native coarctation are candidates for balloon dilatation. Long-segment coarctations or those associated with significant isthmic hypoplasia may be candidates for stent placement, especially in

**4.3.3.3 Echocardiogram** 

coarctation (pulsed Doppler), respectively.

**4.3.4 Catheterization and angiography** 

the aortic narrowing.

**4.3.5 Management** 

adolescents and adults (Figure 7).

years.

extension of the Doppler velocity (Rao and Carey 1989).

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

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 intermediateterm follow-up (p 0.01).

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

Congenital Heart Defects – A Review 17

**The ECG** shows mild right ventricular hypertrophy; the so-called diastolic volume overload

Echocardiographic studies reveal enlarged right ventricle with paradoxical septal motion, particularly well-demonstrable on M-mode echocardiograms. By two-dimensional echocardiogram, the defect can be clearly visualized (Figure 9A). The type of ASD, secundum versus primum can also be delineated by the echocardiographic study. Apical and precordial views may show "septal drop-outs" without an ASD because of thinness of the septum in the region of fossa ovalis. Therefore, only subcostal views should be scrutinized for evidence of ASD. In addition, demonstration of flow across the defect with pulsed Doppler (not shown) and color Doppler (Figure 9B) echocardiography is necessary to avid false positive studied. In adolescents and adults transesophageal echo is needed to

Fig. 9. Two dimensional subcostal echocardiographic view of the atrial septum (A) demonstrating a secundum atrial septal defect (ASD) in the mid septum (arrow). Color

Clinical and echocardiographic features are sufficiently characteristic so that cardiac catheterization is not necessary for the diagnosis. However, cardiac catheterization is an

When catheterization is performed, one will observe step-up in oxygen saturation at the right atrial level. The pulmonary venous, left atrial, left ventricular and aortic saturations are within normal range. In large defects, the pressures in both atria are equal while in small defects, an inter-atrial pressure difference is noted. The right ventricular and pulmonary arterial pressures are usually normal. Calculated pulmonary-to-systemic flow ratio (Qp:Qs) is used to quantitate the degree of shunting and a Qp:Qs in excess of 1.5:1 is considered an

Doppler imaging shows left-to-right shunt. LA, left atrium; RA, right atrium.

**5.1.3.2 Electrocardiogram** 

**5.1.3.3 Echocardiogram** 

make definitive diagnosis of ASD.

**5.1.4 Catheterization and angiography** 

indication for closure of ASD.

integral part of transcatheter occlusion of the ASD.

pattern with rSR' pattern in the right chest leads.

should be two or more times the size of the coarcted segment, but no larger than the diameter of the descending aorta at the level of diaphragm. The immediate (Figures 8) and intermediate-term results of balloon coarctation angioplasty have been good although longterm follow-up is limited (Rao 1999).
