**4.1.7 Management**

Until early 1980s, surgical pulmonary valvotomy was the only treatment available, but at the present time relief of pulmonary valve obstruction can be accomplished by balloon pulmonary valvuloplasty. Indeed, at the present time balloon pulmonary valvuloplasty is treatment of choice. The indications for intervention are similar to those prescribed for surgery: a peak-to-peak systolic pressure gradient > 50 mmHg across the pulmonary valve with a normal cardiac index (Rao 1988, Rao 1989b, Rao 1998). Detailed description of the procedure of balloon valvuloplasty and the results of such a procedure are beyond the scope of this chapter; the reader is referred elsewhere for these details (Rao 2007a, Rao 2007b). In brief, a balloon catheter (with a deflated balloon) is positioned across the pulmonary valve and the balloon inflated (Figure 3); the radial forces of balloon inflation produce valve leaflet commissural disruption and thus relief of pulmonary valve obstruction (Rao 1993).

Fig. 3. Selected cineradiographic frames of a balloon dilatation catheter placed across the pulmonary valve. Note "waisting" of the balloon during the initial phases of balloon inflation (A), which is almost completely abolished during the later phases of balloon inflation (B). Reproduced with permission of the author and publisher, Rao PS: Transcatheter Therapy in Pediatric Cardiology, Wiley-Liss, Inc, New York, 1993, p. 62.

usually reveals thickened and domed pulmonary valve leaflets with a thin jet of passage of contrast across the pulmonary valve. Enlargement of the right ventricle and dilated main pulmonary artery segment are also seen. In patients with severe or long-standing

The natural history studies (Nugent et al 1977) have classified the degree of pulmonary valve obstruction based on peak-to-peak catheter-measured pulmonary valvar gradient: trivial = gradient 25 mmHg; mild = gradient 25-49 mmHg; moderate = gradient 50 to 79 mmHg and severe = gradient > 80 mmHg. Patients with trivial and mild (gradients 50 mmHg) pulmonary stenosis generally remain mild at follow-up. Patients with moderate stenosis (gradients of 50 to 79 mmHg) in contradistinction to trivial and mild stenosis,

Until early 1980s, surgical pulmonary valvotomy was the only treatment available, but at the present time relief of pulmonary valve obstruction can be accomplished by balloon pulmonary valvuloplasty. Indeed, at the present time balloon pulmonary valvuloplasty is treatment of choice. The indications for intervention are similar to those prescribed for surgery: a peak-to-peak systolic pressure gradient > 50 mmHg across the pulmonary valve with a normal cardiac index (Rao 1988, Rao 1989b, Rao 1998). Detailed description of the procedure of balloon valvuloplasty and the results of such a procedure are beyond the scope of this chapter; the reader is referred elsewhere for these details (Rao 2007a, Rao 2007b). In brief, a balloon catheter (with a deflated balloon) is positioned across the pulmonary valve and the balloon inflated (Figure 3); the radial forces of balloon inflation produce valve leaflet

commissural disruption and thus relief of pulmonary valve obstruction (Rao 1993).

Fig. 3. Selected cineradiographic frames of a balloon dilatation catheter placed across the pulmonary valve. Note "waisting" of the balloon during the initial phases of balloon inflation (A), which is almost completely abolished during the later phases of balloon inflation (B). Reproduced with permission of the author and publisher, Rao PS: Transcatheter Therapy in Pediatric Cardiology, Wiley-Liss, Inc, New York, 1993, p. 62.

pulmonary valve obstruction, infundibular constriction may be seen.

**4.1.6 Natural history** 

**4.1.7 Management** 

progressively increase their gradient

Previous recommendations are to use a balloon that is 1.2 to 1.4 times the size of the pulmonary valve annulus; however, more recent recommendations are to limit the balloon/annulus ratio to 1.2 to 1.25 (Rao 2000b, Rao 2007a, Rao 2007b). When the pulmonary valve annulus is too large to dilate with a single balloon, valvuloplasty with simultaneous inflation of two balloons across the pulmonary valve annulus is recommended. Immediate, short-term and long-term results (Figure 4) are good; although long-term results are limited (Rao et al 1998).

Fig. 4. Bar graph showing maximum peak instantaneous Doppler gradients, indicative of severity of pulmonary stenosis, prior to (Pre), one day following (Post) balloon pulmonary valvuloplasty and at intermediate-term (ITFU) and late (LTFU) follow-up. Note significant reduction (p 0.001) after valvuloplasty, which remains unchanged (p 0.1) at ITFU. However, at LTFU there was further fall (p 0.01) in the Doppler gradients.

Given the success with balloon pulmonary valvuloplasty, surgery is reserved for unsuccessful balloon cases, mostly for cases with supravalvar PS, severe valve annular hypoplasia and dysplastic pulmonary valves.

In patients with mild pulmonary valve stenosis, periodic clinical follow-up, antibiotic prophylaxis prior to any bacteremia-producing procedures to prevent subacute bacterial endocarditis and no exercise restriction are recommended.

#### **4.2 Aortic stenosis**

Left ventricular outflow tract obstruction may occur at valvar, subvalvar (fixed subaortic stenosis and idiopathic hypertrophic subaortic stenosis) and supravalvar locations (Singh and Rao 2009). Valvar stenosis is the most common form and will be discussed in this section. The prevalence of congenital valvar aortic stenosis (AS) is 5% to 6% of patients with CHD. The pathology of the stenotic aortic valve is variable, most commonly it is a bicuspid valve with varying degrees of commissural fusion of thickened, domed, nonpliable valve leaflets. Tricuspid and rarely unicuspid aortic valve leaflets can also cause aortic valve obstruction. Dysplasia of the aortic valve leaflets with or without hypoplasia of the valve ring may be found in neonates and young infants. Calcification of

Congenital Heart Defects – A Review 11

may be seen by color Doppler, even in patients without auscultatory evidence for aortic

Fig. 5. Short axis views of the aorta showing aortic valve leaflets in closed (a) and open position (b) in children with tricuspid aortic valves (a and b). Bicuspid aortic valve (large arrows) is shown in c, which is commonly associated with aortic stenosis. Three aortic valve cusps and commissures ( in a) are clearly seen and contrast with two valve cusps and single horizontal commissure (in c). Arrow heads in b point to open aortic valve leaflets. Neither of the children showed clinical or echo-Doppler evidence for aortic stenosis and are shown here only to demonstrate the bicuspid and tricuspid valve leaflets. LA, left atrium; RA, right

The data show elevated left ventricular peak systolic pressure with a peak-to-peak pressure gradient across the aortic valve indicative of the severity of obstruction. Angiography will

The indications for intervention in valvar AS is a peak-to-peak gradient >50 mmHg with either symptoms or electrocardiographic ST-T wave changes or a peak gradient >70 mmHg irrespective of symptoms or ECG changes (Rao 1989b, Rao 1990). When pressure gradients are used as criteria for intervention (instead of valve area), it must be assured that the cardiac index is normal during pressure measurement. Until recently, surgical commissurotomy was the treatment of choice. Since the introduction of balloon valvuloplasty for valvar AS in 1983, increasing number of pediatric cardiologists, including the author of this chapter have been using balloon aortic valvuloplasty as a first therapeutic procedure for relief of aortic valve obstruction although, at this time, there is no consensus with regard to the choice of treatment mode. When surgical commissurotomy is chosen it is usually performed on cardiopulmonary bypass. When balloon valvuloplasty is performed, a

confirm thickened domed aortic valve leaflets and exclude any other abnormalities.

regurgitation.

atrium; RV, right ventricle.

**4.2.5 Management** 

**4.2.4 Cardiac catheterization and angiography** 

the aortic valve leaflets so frequent in the elderly is uncommon during childhood. Dilatation of ascending aorta, post-stenotic dilatation, is seen in most cases, and the extent of aortic dilatation is independent of the severity of aortic obstruction. Hypertrophy of the left ventricular muscle is concentric in nature and is largely proportional to the degree of obstruction.
