Aortic valve repair in children

My name is Joseph Dearani and I am the Chair of Cardiovascular Surgery in Mayo Clinic in Rochester, Minnesota and my area of expertise is in pediatric and congenital heart disease.

Today we're going to talk about the treatment of aortic valve disease in children, which presents a challenging dilemma. The difficulty has to do with the benefits of early surgery to protect the heart from pressure and volume overload from either aortic stenosis or aortic regurgitation versus the lack of a sub-optimal valve substitute in children and the limited durability provided by the various aortic valve repair techniques.

Causes of aortic valve disease in infants and children include either changes in the aortic valve leaflets or changes in the geometry of the aortic root. In general, the repair technique is tailored to each individual anatomy encountered. The indications for surgery, or in some cases balloon valvuloplasty with aortic stenosis is more vague in children and includes a peak-to-peak pressure gradient that exceeds 40 to 50 mmHg, the presence of left ventricular hypertrophy or strain on the electrocardiogram, or evidence of left ventricular dysfunction with exercise testing.

Importantly, symptoms are often a late finding with aortic stenosis and intervention is usually advised on the basis of abnormal diagnostic and imaging studies and should be advised before obvious symptoms become present. Indications for surgery with aortic regurgitation include severe diastolic flow reversal in the descending thoracic aorta that results in progressive volume loading on the left ventricle, presence of an increase left ventricular end-diastolic volume that exceeds three standard deviations on appropriate afterload reduction therapy, the presence of reduced systolic function with exercise or just general decreased exercise tolerance.

Pre-operative imaging, particularly two dimensional and the more recent three dimensional echocardiogram, can provide very valuable information about the aortic root anatomy and valve structures, the mechanism of the valve dysfunction, and it really helps guide the surgeon with strategies for valve repair. As mentioned earlier, aortic valve repair — the technique applied is generally tailored to the individual anatomy encountered. It is important to know that aortic valve repair is viewed as palliative, often temporizing for the eventual valve replacement, which in children is usually the Ross procedure, or the autograft procedure. Concern about autograft root dilatation over time has resulted in the approach of one or more valve repairs being performed in order to delay the ultimate or inevitable autograft operation. Tissue-engineered valve research has been underway for many years now and provides promise for the future.

The most common congenital heart defect, interestingly, is the bicuspid aortic valve. Infants and children with congenital aortic stenosis are often treated with balloon valvuloplasty at first. Surgical valvotomy is ultimately required in about a third of these patients within the subsequent five years. In older children, dilatation of the ascending aorta can result in aortic regurgitation, and this is much more common in the conotruncal anomalies — such as tetralogy of Fallot, pulmonary atresia with ventricular septal defect, truncus arteriosus, double outlet right ventricle, and Marfan and some of the other syndromes.

In general, valve repair techniques are preferred and the valvuloplasty technique of the aortic valve is often the most difficult of all valve repairs present. Many valve repair techniques have been described and include suture repair of leaflet tears or fenestration, commissurotomy, re-suspension of prolapsing leaflets, thinning of thickened leaflets, free margin placation, leaflet resection, and leaflet free edge shortening or leaflet extension maneuvers.

Importantly, repair techniques often require a combination of the above described approaches to obtain a valve that doesn't leak and is not obstructive and the outcome is directly proportional to the experience of the surgeon. The risk of surgery is generally low, particularly beyond the neonatal and infancy periods. Unfortunately, a third to half of patients will require re-intervention within five to 10 years. Mayo has a surgical history exceeding 50 years and an extensive track record of surgery in thousands of patients with aortic valve lesions, both stenosis and regurgitation, in all age brackets — from the newborn, through childhood, and on up into adulthood. Thank you very much for listening to this topic on aortic valve disease in children.