Author + information
- Victor Bautista-Hernandez, MD, PhD,
- Patrick O. Myers, MD,
- Hugo Loyola, MD,
- Gerald R. Marx, MD,
- Emile A. Bacha, MD,
- Christopher W. Baird, MD and
- Pedro J. del Nido, MD⁎ ()
- ↵⁎Department of Cardiac Surgery, Children's Hospital Boston, 300 Longwood Avenue, Boston, Massachusetts 02115
To the Editor:
Atrioventricular (AV) valve repair for regurgitation has been shown to be preferable to valve replacement in young children (1). Besides valvuloplasty technique, annulus reduction and stabilization with a ring have been demonstrated to be necessary to maintain effective leaflet coaptation. In young children, however, placement of a permanent annuloplasty ring is rarely performed because it carries the risk that a re-operation will likely be required as the child grows.
The concept of annuloplasty with biodegradable material, as an adjunct to AV valve repair, is not new. More recently, a flexible intra-annular AV valve ring that is constructed of absorbable biopolymer has been introduced for mitral valve (MV) and tricuspid valve repair (2,3). Unlike rigid or semirigid rings, this new device is a partial ring made of flexible material, which loses tensile strength as the ring material absorbs, thus potentially permitting normal growth of the valve annulus. There are limited data available on outcomes of absorbable ring implantation in young children with complex congenital heart disease (CHD).
Six children (4 months to 8 years, median age: 5.4 years) with CHD and severe AV valve regurgitation underwent AV valve plasty and insertion of a biodegradable annuloplasty ring (Bioring SA, Lonay, Switzerland). Four children had previously had AV canal defect repair (2 had associated heterotaxy syndrome and 1 Shone's complex), 1 a dysplastic MV, and another had hypoplastic left heart syndrome. Food and Drug Administration approval for device implantation was obtained for all patients under compassionate use exemption. Institutional review board approval and informed consent were obtained on all patients.
There were no perioperative deaths or complications such as AV block or coronary compromise. By early post-operative echocardiography, the AV valve anteroposterior (AP) and lateral diameters, areas, and related z-scores were significantly reduced in all 6 patients (p < 0.05 for all variables) and increased—while remaining in the normal range—during the follow-up period (Fig. 1). This reduction was more pronounced on the AP diameter, thus creating the more typical oval-shaped AV valve annulus.
During a mean follow-up of 42 months (range: 26 to 48 months), there were no deaths, late-onset arrhythmias, or ventricular dysfunction. Four patients required reoperation, 2 nonrelated to the AV valve (aortic valve replacement and Fontan completion). One patient with a dysplastic MV required reoperation for mitral stenosis due to recurrent endocardial fibroelastosis. None of the other 5 patients had evidence of significant stenosis, with a mean post-operative, and at latest follow-up, inflow gradient of 2.0 ± 2.5 mm Hg and 2.7 ± 4.3 mm Hg, respectively. One patient with an AV canal defect was reoperated on late for dehiscence of the superior bridging leaflet of the left AV valve. This leaflet had been detached and repositioned to eliminate subaortic obstruction. In both redo patients, the bioring was fully reabsorbed and subsituted by fibrotic tissue located in the intra-annular position. One patient with AV canal redeveloped significant AV valve regurgitation 2 years after repair, but remains asymptomatic with stable left ventricular dimensions and function.
Valve repair in children is challenging due to the complexity of the underlying anatomic abnormalities and growth of the valvular structures over time. Unlike adults, implanting an annuloplasty ring is usually not performed in young children due to the risk of acquired stenosis with growth. We have evaluated our results with the bioring in 6 pediatric patients with complex CHD and severe AV valve regurgitation. In our series, all patients had a significant reduction and normalization of the annular measurements after ring implantation. We did, however, observe annular growth over time, which was proportional to somatic growth because the z-scores remained normal, and with a more oval-shaped annulus than before valvuloplasty (Fig. 1).
The pediatric experience with absorbable annuloplasty ring implantation has been primarily in Europe, where this device is available for clinical use. Kalangos et al. (4) recently updated their experience with this device in children with rheumatic MV disease. The use of a biodegradable MV ring resulted in a significantly lower mean gradient during the first year of implantation compared with the Carpentier-Edwards ring. However, the mean age of the patients in this study was 11.8 years at repair, which is significantly older than our study population. A more recent report on 11 children (median age: 4.5 years) undergoing tricuspid valve repair with the bioring demonstrated tricuspid annular growth over time (3).
In summary, we have used an absorbable annuloplasty partial ring in 6 children with complex CHD and achieved a competent AV valve with normalization of the AP and lateral diameters, area, and z-scores. During a median follow-up of 42 months, reduction of those parameters remains significant, and the annulus area has increased appropriate to somatic growth. This time period is important because the prosthesis is predicted to be absorbed after 6 months of implantation. Our initial experience and the published experience in Europe indicate that a larger clinical trial with this ring is warranted.
- American College of Cardiology Foundation
- Selamet Tierney E.S.,
- Pigula F.A.,
- Berul C.I.,
- Lock J.E.,
- del Nido P.J.,
- McElhinney D.B.