Aortic insufficiency in young patients


 * Associate Editors-in-Chief: Varun Kumar, M.B.B.S., Lakshmi Gopalakrishnan, M.B.B.S.

Overview
Congenital aortic insufficiency rarely occurs alone and is often associated with aortic stenosis or ventricular septal defect. It may occasionally be observed in adolescents and young adults with a bicuspid aortic valve, discrete subaortic obstruction, or prolapse of one of the aortic cusp into a ventricular septal defect. Turner syndrome, osteogenesis imperfecta, Tetralogy of Fallot, and truncus arteriosus are other congenital disorders that are associated with aortic insufficiency in young patients.

Rheumatic heart disease is one of the important causes for acquired aortic insufficiency in young patients in developing countries. It can also occur following an episode of infective endocarditis or as a consequence of attempts to relieve aortic stenosis by either balloon valvuloplasty or surgical valvulotomy, or when the pulmonary artery is relocated in the aortic position during repair of transposition of great vessels.

Symptoms
The majority of young patients remain asymptomatic even with severe aortic insufficiency.

Echoardiogrpahy
These patients should be followed-up with serial echocardiographic assessment, including measurement of ventricular dimensions, volumes, and function. This could assist in determining the timing of surgical repair.

Medical Management
Vasodilators are indicated in patients who have moderate to severe aortic insufficiency, are symptomatic or in those who have concurrent hypertension. ACE inhibitors with captopril in particular may be beneficial in children with partial improvement in left ventricular end-diastolic and end-systolic dimensions, end-diastolic and end-systolic volume indexes, mass index determined by 2D echocardiography and wall stresses also decreased significantly with therapy. A study on benefits of ACE inhibitor in 20 children with aortic insufficiency showed that there was approximately 28% reduction in regurgitant fraction at the end of 1year of treatment.

Surgical Management
Surgery is indicated in young patients with aortic insufficiency who are:
 * symptomatic or
 * having left ventricular dysfunction (ejection fraction < 50%) or
 * increased left ventricular end-diastolic/systolic dimension (body size should be taken into account).

These indications are similar to those in adults. The choice between aortic valve replacement vs aortic valve repair depends on the cause of aortic insufficiency.

Aortic valve repair is effective in patients who developed aortic insufficiency after undergoing balloon valvuloplasty for aortic stenosis and in those who have prolapsed cusps in VSD. In a study on 21 patients aged between 9 months to 15years who underwent valve repair for aortic insufficiency secondary to balloon dilatation for aortic stenosis showed 100% freedom from reoperation for late failure, and 80% overall freedom from reintervention at 3 years with significant reduction in regurgitant fraction, left ventricular end-diastolic dimension, and proximal regurgitant jet/aortic annulus diameter ratio. Freedom from reoperation was 95%, 87% and 84% at 1, 5 and 7 years, respectively in patients undergoing valve repair for cusp prolapse.
 * Aortic valve repair


 * Aortic valve replacement

Aortic valve replacement is another treatment option where mechanical or bioprosthetic valves can be used. Though use of bioprosthetic valves reduces the need for long term systemic anticoagulation, they have a high failure rate of 20% in children due to valve degeneration and calcification. Mechanical valves with prolonged anticoagulation are preferred as they showed better outcome in yound patients with normalization of end-diastolic volume, left ventricular ejection fraction and peak systolic strain of the left ventricular myocardium.


 * Ross or Ross/Konno procedure

Ross procedure is another alternative surgical procedure where the pulmonary valve is transplanted to the aortic position, and a homograft conduit is implanted from the right ventricle to the pulmonary artery. Though this procedure shows promising results for aortic valve abnormalities in some , the use of this technique has been limited by high rates of pulmonary autograft failure with deterioration of right heart homografts. These rates are higher in children as compared to adults. Further studies aimed at clarifying longer-term outcomes as well as preventing pulmonary homograft deteroration are needed.

To summarize, mechanical valve replacement is the preferred surgical option at present in young patients as opposed to valve repair or biological valve replacement in view of lack of evidence of long-term durability and outcomes. However they may be appropriate for patients in whom anticoagulation are contraindicated.

==AHA/ACC guidelines for treatment of aortic insufficiency in adolescent or young adults == {{cquote|

Class I
1. An adolescent or young adult with chronic severe aortic insufficiency with onset of symptoms of angina, syncope, or dyspnea on exertion should receive aortic valve repair or replacement. (Level of Evidence: C)

2. Asymptomatic adolescent or young adult patients with chronic severe aortic insufficiency with left ventricular systolic dysfunction (ejection fraction less than 0.50) on serial studies 1 to 3 months apart should receive aortic valve repair or replacement. (Level of Evidence: C)

3. Asymptomatic adolescent or young adult patients with chronic severe aortic insufficiency with progressive left ventricualr enlargement (end-diastolic dimension greater than 4 standard deviations above normal) should receive aortic valve repair or replacement. (Level of Evidence: C)

4. Coronary angiography is recommended before AVR in adolescent or young adult patients with aortic insufficiency in whom a pulmonary autograft (Ross operation) is contemplated when the origin of the coronary arteries has not been identiﬁed by noninvasive techniques. (Level of Evidence: C)

Class IIb
1.An asymptomatic adolescent with chronic severe aortic insufficiency with moderate aortic stenosis (peak left ventricle–to–peak aortic gradient greater than 40 mm Hg at cardiac catheterization) may be considered for aortic valve repair or replacement. (Level of Evidence: C)''

2. An asymptomatic adolescent with chronic severe aortic insufficiency with onset of ST depression or T-wave inversion over the left precordium on electrocardiogram at rest may be considered for aortic valve repair or replacement. (Level of Evidence: C)}}