Hybrid Interventions in Congenital Heart Disease: A Review of Current Practice and Rationale for Use.

BACKGROUND: Hybrid interventions have become a common option in the management for a variety of patients with congenital heart disease. In this review, we discuss the data that have driven decision making about hybrid interventions to date. METHODS: The existing literature on various hybrid approaches was reviewed and summarized. In addition, the key tenants to creating a successful hybrid program within a congenital heart center are elucidated. RESULTS: Hybrid strategies for single-ventricle patients, pulmonary atresia with intact ventricular septum, branch pulmonary artery stenosis, and muscular ventricular septal defect closure have important benefits and limitations compared with traditional approaches. CONCLUSION: A growing body of evidence supports the use of hybrid interventions in congenital heart disease. But important questions remain regarding improved survival and other long-term outcomes, such as neurocognition, that might impact widespread adoption as a primary treatment strategy.

Absence of TGFBR1 and TGFBR2 mutations in patients with bicuspid aortic valve and aortic dilation.

Mutations in the genes encoding transforming growth factor-beta receptor types I and II (TGFBR1 and TGFBR2, respectively) are commonly identified in patients with Loeys-Dietz syndrome, as well as some patients with Marfan's syndrome or familial thoracic aortic aneurysms and dissections. This suggests that there is considerable phenotypic heterogeneity associated with mutations in these genes. Because bicuspid aortic valve (BAV) is a congenital heart defect in patients with Loeys-Dietz syndrome, this study was conducted to investigate whether variants in TGFBR1 or TGFBR2 are responsible for sporadic BAV. Analysis of these genes in 35 patients with BAVs identified only known single-nucleotide polymorphisms or novel synonymous or intronic substitutions. In conclusion, mutations in TGFBR1 and TGFBR2 rarely cause sporadic BAV.

Late gadolinium enhancement: precursor to cardiomyopathy in Duchenne muscular dystrophy?

BACKGROUND: Progressive cardiomyopathy is a common cause of death in Duchenne muscular dystrophy (DMD), presumably secondary to fibrosis of the myocardium. The posterobasal and left lateral free wall of the left ventricle (LV) are initial sites of myocardial fibrosis pathologically. The purposes of this study were to assess whether cardiac magnetic resonance imaging (CMRI), utilizing late gadolinium enhancement (LGE), could identify fibrosis in selective areas of the myocardium, and to assess the relationship of the presence and extent of fibrosis to LV function. METHODS: The cardiology databases at Primary Children's Medical Center and Cincinnati Children's Hospital Medical Center were reviewed to identify patients with DMD who had undergone a CMRI within the last 2 years. Age, LV ejection fraction, LV mass, presence and location of LGE were documented. Volumes were measured using MASS (Medis, Inc.) to calculate ejection fraction and mass. LGE images were acquired and when positive, customized computer assisted sizing of the areas of late gadolinium enhancement were performed on all slices. Normal function was defined as LV ejection fraction >54%. RESULTS: A total of 74 patients with DMD had complete data sets (median age 13.7 years, range 7.7-26.4). Twenty-four patients (32%) had LGE involving the posterobasal region of the LV in a sub-epicardial distribution. Those patients with more involvement had spread to the inferior and left lateral free wall with progressive transmural fibrous replacement. There was relative sparing of the interventricular septum and right ventricle. Patients with LGE were significantly older than those without (mean age 16.4 vs 12.9 years, P < 0.001). LGE was positively associated with BSA-adjusted LV mass, LV end-diastolic volume, LV end-systolic volume, and RV end-systolic volume but inversely correlated with ejection fraction of the LV (P < 0.001) and RV (P = 0.004). CONCLUSIONS: LGE by CMRI is able to detect fibrosis in selective regions of myocardium in patients with DMD. Unfavorable LV remodeling, with a corresponding decreased ejection fraction, is associated with the presence of LGE. Serial studies are warranted to determine if LGE precedes a decrease in function, and if early medical management is useful in preventing progression once LGE is documented.

Pulmonary regurgitation: determining severity by echocardiography and magnetic resonance imaging.

OBJECTIVE: Pulmonary regurgitation (PR) is common after repair of congenital heart disease involving the right ventricular outflow tract. Because PR results in chronic right ventricular volume overload and associated morbidity and mortality, accurate assessment of its severity is important. The aim of this study was to compare echocardiography with the gold standard of PR quantitation by magnetic resonance imaging (MRI) in a young population with repaired congenital heart disease. DESIGN/METHODS: Patients with congenital heart disease who had undergone right ventricular outflow tract reconstruction and/or pulmonary valve replacement and had an MRI within 3 months of an echocardiogram formed the study group. Echocardiographic indices were compared with MRI-determined pulmonary regurgitant fraction (PRF) to determine the most accurate measurements to quantitate PR. RESULTS: Of the 69 MRI/echocardiography pairs in 64 patients, 53 data sets were complete and used in the analysis. For the prediction of MRI PRF > or =20%, PR jet width/annulus ratio > or =0.5 demonstrated excellent sensitivity (94%), specificity (100%), positive predictive value (PPV 100%), and negative predictive value (NPV 82%). For the prediction of MRI PRF > or =40%, jet width/annulus ratio > or =0.7 and diastolic flow reversal in the branch pulmonary arteries showed useful sensitivity (92%), specificity (68%), PPV (76%), and NPV (88%). CONCLUSION: Pulmonary regurgitation jet width/annulus ratio combined with diastolic flow reversal is the most valuable echocardiographic measure for assessing PR severity after right ventricular outflow tract reconstruction or pulmonary valve replacement; however, this surrogate measure does not replace the importance of MRI evaluation.

Right ventricle-to-pulmonary artery conduit longevity: is it related to allograft size?

BACKGROUND: Cryopreserved valved allografts are routinely oversized to account for somatic growth in children requiring right ventricle-to-pulmonary artery (RV-PA) continuity. The objective of this study is to determine the effect of oversizing on conduit longevity. METHODS: We reviewed the records of all patients undergoing RV-PA cryopreserved valved allograft placement from 1988 to 2006 for diagnosis, age, allograft type, time to valved conduit explant, and indication for surgery. Conduit size at the time of insertion was compared with pulmonary valve size normalized for body surface area (z score). Multivariate Cox regression models with cluster analysis were constructed to assess risk of allograft oversizing for conduit failure. Kaplan-Meier analysis was used to obtain median freedom from explantation time. RESULTS: A total of 140 cryopreserved valved allografts (z score, 1.8 +/- 1.3; range, -1.5 to 4.9) were implanted in 99 patients (median age, 5.6 years). Reoperation was required in 66 (67%) of 99 patients during the study period. Modeling z scores as a dichotomous variable revealed that risk of allograft explantation increases 113% when allografts with z scores of 2.7 or higher are used compared with those with z scores of less than 2.7 (p < 0.01). Median adjusted freedom from explantation for this same grouping was 4.9 years versus 9.4 years. The presence of branch pulmonary artery stenosis shortens the conduit life (p < 0.001), whereas insertion of a pulmonary allograft may extend the conduit life (p = 0.13). CONCLUSIONS: Cryopreserved valved allograft oversizing (z score > or = 2.7) in the pulmonary position results in decreased longevity in children. Presence of branch pulmonary artery stenosis is also associated with earlier conduit explantation.