Congenital aortic valve repair using CorMatrix® : A histologic evaluation.

BACKGROUND: The reconstruction of heart valves provides substantial benefits, particularly in the pediatric population. We present our experience using decellularized extracellular matrix (dECM, CorMatrix® ) for aortic valve procedures. METHODS: We retrospectively reviewed the case histories of 6 patients (aged from 2 months - 14 years) who underwent surgery for severe aortic valve stenosis (n = 4) or regurgitation (n = 2). Aortic valve repair was performed on all patients using dECM as a leaflet replacement or leaflet extension. Follow-ups were performed using echocardiography. Reoperation was necessary in 4 cases, and the dECM was explanted and examined histologically and immunohistochemically. RESULTS: The early post-operative period was uneventful, and the scaffold fulfilled the mechanical requirements. Significant valve insufficiency developed in 5 patients during the post-operative period (119-441 days postoperatively). In all specimens, only a migration of inflammatory cells was identified, which induced structural and functional changes caused by the chronic inflammatory response. CONCLUSIONS: Our results suggest a mixed immunological response of remodeling and inflammation following the implantation. The expected process of seeding/migration and remodeling of the bioscaffold into the typical 3-layered architecture were not observed in our explanted specimens.

Realignment of the ventricular septum using partial direct closure of the ventricular septal defect in Tetralogy of Fallot.

OBJECTIVE: The aim is to describe our technique of partial direct closure of the ventricular septal defect (VSD) in Tetralogy of Fallot (TOF), and assess its influence on the realignment and remodeling of the left ventricular outflow tract. METHODS: Between 2004 and 2010, 32 non-consecutive patients with TOF underwent a direct or partial direct closure of VSD. Median age and weight were 5.2 months and 6.7 kg, respectively. An approach through the right atrium was used in 30 patients and through the infundibulum in two patients. The conal septum was mobilized by transecting the hypertrophic trabeculae to facilitate the approximation of the VSD. The membranous part of the VSD was closed (in the later part of the series) with a small xenopericardial patch to avoid tension on the suture line traversing the area of risk to the bundle of His. Follow-up was complete, with a median duration of 46.9 (range 12-75.3) months. RESULTS: The VSD could be closed successfully in all patients. A residual VSD was partly responsible for one early postoperative re-operation. There were no early or late deaths. At follow-up, all patients were in sinus rhythm. Three patients showed a small residual VSD. Thirty patients had none, one showed trivial, and one had mild aortic regurgitation. The left ventricular outflow showed a good realignment of the ventricular septum in all the patients. CONCLUSIONS: Partial direct closure of the VSD corrects the primary defect in TOF, that is, the malalignment of the septum. It results in a straight, wide open left ventricular outflow tract and brings better support to the aortic root.

Brain natriuretic peptide and magnetic resonance imaging in tetralogy with right ventricular dilatation.

BACKGROUND: Cardiac volumetry by magnetic resonance imaging can guide the timing for reoperation in minimally symptomatic or asymptomatic patients with pulmonary insufficiency after corrected tetralogy of Fallot. Pro-brain natriuretic peptide (BNP) is a marker of ventricular dysfunction and wall stress, and levels may complement magnetic resonance imaging in cardiac assessment before and after pulmonary valve replacement. METHODS: Between May 2004 and October 2005, 23 consecutive patients with corrected tetralogy, severe pulmonary insufficiency, and right ventricular end-diastolic volume index greater than 150 mL/m2 underwent elective pulmonary valve replacement. Plasma proBNP levels and magnetic resonance imaging were obtained before and 6 months after pulmonary valve replacement. RESULTS: There was no surgical mortality or morbidity. Preoperative right ventricular end-diastolic volume index correlated with pulmonary insufficiency, and inversely so with left ventricular ejection fraction, reflecting interventricular interaction. Preoperatively (r = -0.47) and 6 months postoperatively (r = -0.54), log BNP was inversely correlated with right ventricular ejection fraction. Mean preoperative proBNP levels, right ventricular end-diastolic volume index, and pulmonary insufficiency significantly (p < 0.0001) diminished 6 months after pulmonary valve replacement (231 versus 114 ng/L, 184 versus 109 mL/m2, and 44% versus 2%, respectively). CONCLUSIONS: Plasma proBNP is elevated in patients with corrected tetralogy, severe pulmonary insufficiency, and right ventricular dilatation, and it significantly diminishes 6 months after pulmonary valve replacement, mirroring magnetic resonance imaging-documented better right ventricular ejection fraction and smaller right ventricular end-diastolic volume index. Pro-brain natriuretic peptide complements magnetic resonance imaging for cardiac assessment in patients requiring pulmonary valve insertion. Future validation of cutoff levels are required to establish proBNP as a useful diagnostic and follow-up tool in patients with chronic pulmonary insufficiency and failing right ventricles.

Remodelling of the right ventricle after early pulmonary valve replacement in children with repaired tetralogy of Fallot: assessment by cardiovascular magnetic resonance.

AIMS: Correct timing of pulmonary valve replacement (PVR) is crucial for preventing complications of pulmonary regurgitation and right ventricular (RV) dilatation after repair of tetralogy of Fallot. We sought to assess the remodelling of the RV after early PVR in children, using cardiovascular magnetic resonance (CMR). METHODS AND RESULTS: Twenty children with severe pulmonary regurgitation and RV dilatation and mean age 13.9 +/- 3 years underwent CMR evaluation 5.6 +/- 1.8 months before and 5.9 +/- 0.6 months after PVR. PVR was performed when the RV end-diastolic volume exceeded 150 mL/m(2), as measured by CMR. The time interval between primary repair and PVR was 12 +/- 3 years. Post-operative CMR demonstrated a significant reduction of the RV end-diastolic volume from 189.8 +/- 33.4 to 108.7 +/- 25.8 mL/m(2) (P < 0.0001), of the RV end-systolic volume from 102.4 +/- 27.3 to 58.2 +/- 16.3 mL/m(2) (P < 0.0001), and of the RV mass from 48.7 +/- 12.3 to 35.8 +/- 7.7 g/m(2) (P < 0.0001). The RV ejection fraction did not change significantly. CONCLUSION: Prompt RV remodelling, with reduction of RV volume and mass, is observed after performing PVR if the RV end-diastolic volume exceeds 150 mL/m(2). Early PVR may prevent the detrimental complications of severe pulmonary regurgitation.

Early results of the bovine jugular vein graft used for reconstruction of the right ventricular outflow tract.

BACKGROUND: This study is an assessment of early results of bovine jugular vein grafts (BJV) used to reconstruct the right ventricular outflow tract. METHODS: Ninety-three consecutive BJV implantations performed between May 2001 and August 2003 were included in this study. The median age was 7.2 years. Indications included various forms of tetralogy of Fallot and pulmonary atresia (56 patients), aortic valve disease requiring a Ross procedure (21 patients), truncus arteriosus (8 patients), d-transposition of the great arteries with ventricular septal defect and pulmonary stenosis (5 patients) and miscellaneous (3 patients). Additional plasty of the intrapericardial pulmonary arteries was performed in 41 patients. Follow-up was complete with a mean duration of 20.3 +/- 5.8 months. RESULTS: There were 3 patients (3.2%) with early deaths and 2(2.2%) with late deaths, but none were related to the bovine jugular vein grafts. Twelve bovine jugular vein grafts needed reintervention; 11 were due to development of a stenotic membrane at the anastomosis site and one was due to somatic outgrowth of the child (10 conduit replacements and two balloon dilatations). Overall freedom from reintervention was 91.6% and 83.5% at 12 and 24 months, respectively. Small size (< or = 14 mm) conduits show respective rates of 80.7% and 63.6%, whereas larger sizes were 98% and 96%, free from reintervention at 12 and 24 months. CONCLUSIONS: Bovine jugular vein grafts, when used for reconstruction of the right ventricular outflow tract, showed good early-term results. Attrition of small size bovine jugular vein grafts, due to development of a stenotic process at the anastomotic site needs to be closely observed. Longer follow-up is needed to allow a more definitive comparison with other established options.