Alistair Phillips

Hybrid Approach for Hypoplastic Left Heart Syndrome: Intermediate Results After the Learning Curve

BACKGROUND Lessons learned during the development of a novel hybrid approach have resulted in a reliable, reproducible alternative treatment for hypoplastic left heart syndrome (HLHS). Herein we report our results using this hybrid approach in a uniform risk cohort. METHODS This is a review of prospectively collected data on patients treated for HLHS using a hybrid approach (n = 40) between July 2002 and June 2007. The hybrid approach includes pulmonary artery bands, a ductal stent, and atrial septostomy as a neonate, comprehensive stage 2 procedure resulting in Glenn shunt physiology at six months and Fontan completion at two years. RESULTS Forty patients had a hybrid stage 1 with 36 undergoing a comprehensive stage 2 procedure. Fifteen patients have completed the Fontan procedure with 17 pending. Overall survival was 82.5% (33 of 40). The seven deaths included one at stage 1, two between stages 1 and 2, three at stage 2, and one between stages 2 and 3. One patient had successful heart transplantation during the interstage period. CONCLUSIONS The hybrid approach can yield acceptable intermediate results that are comparable with a traditional Norwood strategy. Potential advantages of the hybrid approach include the avoidance of circulatory arrest and shifting the major surgical stage to later in life. These data provide the platform for a prospective trial comparing these two surgical options to assess whether there is less cumulative impact with the hybrid approach, thereby improving end organ function, quality, and quantity of life.

Cytoskeletal remodeling of desmin is a more accurate measure of cardiac dysfunction than fibrosis or myocyte hypertrophy

AIMS Fibrosis and myocyte hypertrophy are classical remodeling parameters in heart failure (HF); however, an intriguing possibility is that myocytes undergo intracellular remodeling which decrease compliance, contributing to diastolic dysfunction. The most obvious candidates are cytoskeletal proteins. The cytoskeletal protein desmin reinforces the sarcomeres, enabling force generation. As a contributor to sarcomere performance, desmin may represent a better appraisal of dysfunction than fibrosis or myocyte hypertrophy. MAIN METHODS HF was induced in sheep via coronary microembolization. Echocardiography was performed at baseline, 4-, and 12-months in HF. Desmin, fibrosis, and myocyte hypertrophy from infarcted LV posterior and noninfarcted LV anterior walls were measured using Western blot, immunohistochemistry, and digital image analysis. Multivariate regression analysis was performed, providing structure/function mechanisms. *p<0.05. KEY FINDINGS EF decreased from 55% to 24%*. LV end-diastolic area (LVEDA) increased 123%* at month-12. Fibrosis increased only in posterior LV whereas myocyte hypertrophy increased in both LV posterior and LV anterior regions but only at month-12. Desmin content progressively increased 121% at month-4 and 182%* at month-12 in both LV posterior and anterior walls. Multivariate linear regression (beta coefficient standardization) demonstrated that desmin was a much better predictor of EF (beta=-0.38*) and LVEDA (beta=0.58*) than fibrosis or myocyte hypertrophy. SIGNIFICANCE Desmin, fibrosis, and myocyte hypertrophy are temporally and spatially heterogeneous in HF. Desmin content more accurately correlated with remodeling than fibrosis or myocyte hypertrophy, suggesting that intra-myocyte responses, likely related to mechanical stretch, are better predictors of LV function and may represent novel targets for therapeutic intervention.

Atrial septal interventions in patients with hypoplastic left heart syndrome

Objectives: To report an institutional experience performing percutaneous atrial septal interventions in patients with hypoplastic left heart syndrome (HLHS). Background: The success of the Hybrid approach in palliating patients with HLHS is crucially dependant on relieving any significant interatrial restriction. Data on transcatheter interventions to relieve atrial septal restrictions in patients with HLHS are limited. Methods: We retrospectively reviewed 67 transcatheter atrial septal interventions that were performed between July 2002 and September 2007 in 56 patients with HLHS. The median weight was 3.35 kg. About 10.7% of patients had an intact atrial septum. Balloon atrial septostomy (BAS) was used in 77.6% of procedures, additional techniques in 35.8% of procedures. Patients were divided into those with standard atrial septal anatomy (group A, n = 33) and those with complex atrial septal anatomy (group B, n = 23). Results: The mean trans‐septal gradient was reduced significantly from 7 mm Hg to 1 mm Hg with the median time to discharge being 3.5 days. Major adverse events were seen in 8.9% of procedures, whereas minor adverse events occurred in 26.8% of procedures. Adverse events were significantly less common in patients with standard atrial septal anatomy, compared to those with complex atrial septal anatomy (25.6% versus 50.0%). About 19.6% patients required repeated atrial septal interventions. Survival up to and including Comprehensive stage II palliation was 73% group A, and 57% in group B. Conclusions: With utilization of appropriate techniques and equipment, atrial septal interventions in HLHS can be performed successfully in virtually all patients. Complex atrial septal anatomy is technically challenging and has a higher incidence of procedural adverse events. In the majority of patients, standard BAS can be performed safely, and is usually the only intervention required to achieve adequate relief of atrial septal restriction until Comprehensive stage II palliation.

Failure of right ventricular adaptation in children with tetralogy of Fallot.

Background— The left ventricle (LV) adapts to chronic hypoxia by expressing protective angiogenic, metabolic, and antioxidant genes to improve O2 delivery and energy production, and to minimize reoxygenation injury. The ability of the right ventricle (RV) to adapt to hypoxia in children with tetralogy of Fallot (TOF) is unknown. Methods and Results— Gene expression using real-time polymerase chain reaction was measured in RV myocardium obtained during surgical repair of TOF from 23 patients: 13 cyanotic and 10 acyanotic. Results were compared between the 2 groups and correlated with age at surgery, severity of cyanosis, and early postoperative course. The cyanotic patients were younger at surgery compared with acyanotic (5±3 versus 9±4 months; P=0.01), had higher hematocrit (43±4 versus 38±3 grams/dL; P=0.004), and lower O2 saturations (84±4% versus 98±2%; (P<0.001). Cyanotic patients had a significantly lower expression of vascular endothelial growth factor (VEGF), glycolytic enzymes, and glutathione peroxidase (GPX) (P<0.05), and a higher expression of collagen (P<0.01) compared with acyanotic patients. Gene expression correlated inversely with severity of cyanosis ie, preoperative hematocrit (P<0.01) and positively with preoperative saturation (P<0.05). The relationship between gene expression and cyanosis was independent of age at surgery. Ca2+ handling genes did not correlate with the severity of hypoxia. Lower angiogenic, glycolytic, and antioxidant gene expression correlated with increasing postoperative lactate (P<0.05). Conclusions— The RV fails to up regulate adaptive pathways in response to increasing hypoxia in children with TOF. The implications of an early maladaptive response of the RV on long-term RV function require further investigation.

Beating-heart patch closure of muscular ventricular septal defects under real-time three-dimensional echocardiographic guidance: A preclinical study

OBJECTIVES Safe and effective device closure of ventricular septal defects remains a challenge. We have developed a transcardiac approach to close ventricular septal defects using a patch delivery and fixation system that can be secured under real-time three-dimensional echocardiographic guidance. METHODS In Yorkshire pigs (n = 8) a coring device was introduced into the left ventricle through a purse-string suture placed on the left ventricular apex, and a muscular ventricular septal defect was created. The patch deployment device containing a 20-mm polyester patch was advanced toward the ventricular septal defect through another purse-string suture on the left ventricular apex, and the patch was deployed under real-time three-dimensional echocardiographic guidance. The anchor delivery device was then introduced into the left ventricle through the first purse-string suture. Nitinol anchors to attach the patch around the ventricular septal defect were deployed under real-time three-dimensional echocardiographic guidance. After patch attachment, residual shunts were sought by means of two-dimensional and three-dimensional color Doppler echocardiography. The heart was then excised, and the septum with the patch was inspected. RESULTS A ventricular septal defect was created in the midventricular (n = 4), anterior (n = 2), and apical (n = 2) septum. The mean size was 9.8 mm (8.2-12.0 mm), as determined by means of two-dimensional color Doppler scanning. The ventricular septal defects were completely closed in 7 animals. In one a 2.4-mm residual shunt was identified. No anatomic structures were compromised. CONCLUSIONS Beating-heart perventricular muscular ventricular septal defect closure without cardiopulmonary bypass can be successfully achieved by using a catheter-based patch delivery and fixation system under real-time three-dimensional echocardiographic guidance. This approach might be a better alternative to cardiac surgery or transcatheter device closure.

Aortic Dissection in the Adult Fontan with Aortic Root Enlargement

A 26-year-old man with a history of hypoplastic left heart syndrome, mitral and pulmonary valve atresia, and malposed great vessels presented with atypical chest pressure. Previous palliation included a lateral tunnel modified Fontan. The man’s physical exam demonstrated aortic insufficiency. Transthoracic echocardiography showed severe dilation of the aortic root measuring 7.8 cm, severe aortic regurgitation, and moderate global right ventricular systolic dysfunction. A multidetector computed tomographic (MDCT) exam confirmed dilation of the aortic root but also identified a dissection flap originating in the sinuses adjacent to the right and noncoronary cusps (Fig. 1). More importantly, the left and right coronaries also were identified but not involved in the dissection. As a consequence of multiple reoperations and the close anatomic relationship between the aorta and the sternum identified by MDCT imaging, the patient was taken to the operating room and prepared for bypass via the right axillary artery and right femoral vein. Furthermore, the sternum was dissected from beneath under direct vision (Fig. 2), using a modification of the technique described by Eddy et al. [2]. The aneurysm was ressected down to the aortic annulus, and the coronary ‘‘buttons’’ were excised. Aortic hemiarch and root replacement were performed using a 26-mm Dacron tube graft and a 29-mm Advancing The Standard valved conduit, respectively. A graft-to-graft anastomosis was done to complete the repair. Postoperatively, the patient returned to the cardiac intensive care unit, where the remainder of his hospital course was uncomplicated. Aortic root replacement as a result of severe aortic dilation and dissection in the adult patient after the Fontan procedure has not been previously described. Aortopathy, however, has been well described in other forms of congenital heart disease including bicuspid aortic valves and tetralogy of Fallot [3, 4]. Although the mechanism of aortic dilation is yet to be determined, current hypotheses include secondary abnormalities in the medial layer of the aorta accompanied by elastic fiber fragmentation leading to increased aortic stiffness [1]. The increasing number of aging adults with complex congenital heart disease continues to present unique complications of previous surgical palliations, often placing intricate demands on the cardiologists who provide care for this patient population [5]. Immediate collaboration with the adult congenital and cardiothoracic surgical teams and a thoughtful surgical approach to this complication certainly avoided the risk of further dissection and death for the reported young patient. M. Egan S. C. Cook (&) Department of Pediatrics, Division of Cardiology, The Heart Center, Nationwide Children’s Hospital, 700 Children’s Drive, 6th Floor EDU, Columbus, OH 43205, USA e-mail: stephen.cook@nationwidechildrens.org

The Impact of Obesity on Early Postoperative Outcomes in Adults with Congenital Heart Disease

BACKGROUND As the prevalence of obesity continues to increase, it now includes the growing number of patients with congenital heart disease (CHD). This particular obese patient population may pose additional intraoperative as well as postoperative challenges that may contribute to poor outcomes. Our aims were to determine the influence of obesity on morbidity and mortality in adults with CHD undergoing surgical repair at a free standing childrens hospital. METHODS A retrospective analysis of adult (≥18 years) CHD surgery cases from 2002 to 2008 was performed. Congenital heart lesions were defined as mild, moderate, or complex. Patients were categorized by body mass index (BMI): underweight (BMI < 20 kg/m(2)), normal (BMI 20-24.9 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)), and obese (BMI ≥ 30 kg/m(2)). Demographics, incidence of mortality, or specific morbidities were statistically compared using Fishers exact test and analyses of variance (anovas). RESULTS In this population (n = 165), overweight (29%) and obese (22%) patients were prevalent. Hypertension (HTN) and pre-HTN were more prevalent in obese and overweight patients. Postoperative renal dysfunction was observed in obese patients with complex CHD (P = .04). Mortality was not different among groups. CONCLUSIONS Obesity is becoming increasingly common among adults with CHD. Despite marginal evidence of postoperative renal complications in obese patients with CHD of severe complexity, the overall presence of obesity did not influence mortality or short term postoperative morbidities.

Quality outcomes of ACHD patients undergoing cardiovascular procedures and hospital admissions in a free-standing children's hospital

OBJECTIVES Describe quality outcomes of adults with congenital heart disease (ACHD) undergoing cardiovascular procedures and admissions in a free-standing childrens hospital with a multi-disciplinary ACHD program and compared with pediatric outcomes. BACKGROUND A challenge for the U.S. healthcare system is where to treat the >1 million ACHD patients (pts): adult hospitals without CHD care, or pediatric hospitals without adult services. METHODS We reviewed all CHD pts ≥ 18 yrs of age from 2002-2007. Procedural and hospital related morbidity and mortality were recorded. ANOVA and t-test compared adult with pediatric pts. RESULTS Overall, 782 pts, mean age of 29.8 ± 9.9 yrs, encountered 1490 procedures/admissions. For 178 cardiac surgeries (72% reoperations), mortality was 1.8% and complication rate was 7.3%. There was 0% mortality for 412 cardiac catheterizations, 311 electrophysiological procedures, 401 transesophageal echocardiograms (TEE), 244 exercise tests (ETT) and 54 medical admissions. Major adverse event rate was 0.6% for cardiac catheterization and electrophysiological procedures. No adverse events occurred during TEE and ETT. Only 4 pts required transfer to an adult institution (0.25%). There was no significant difference in mortality or adverse events between pediatric and adult CHD pts, p>0.05. CONCLUSIONS The optimal setting to provide ACHD care remains a complex issue. Our study is the first to demonstrate 1) a low incidence of morbidity and mortality for ACHD pts undergoing cardiovascular procedures or admissions at a free-standing childrens hospital, 2) outcomes comparable to pediatric CHD pts. Future models incorporating ACHD programs within pediatric heart centers should be considered to care for this complex population.

Hybrid balloon pulmonary valvuloplasty in a 700-g infant: Thinking outside the box.

This report describes a unique Hybrid approach to balloon pulmonary valvuloplasty in a 700‐g premature infant with pulmonary valve stenosis and very poor right ventricular function.

Amplatzer Septal Occluder Associated With Late Pulmonary Venous Obstruction Requiring Surgical Removal With Acquired Aorta to Left Atrial Fistula

The Amplatzer septal occluder is currently the preferred device for the transcatheter closure of secundum atrial septal defects. Multiple studies have shown that device complications with the Amplatzer occluder are rare and often acute in presentation. The investigators describe the first reported case of late obstruction of the right pulmonary veins with an Amplatzer septal occluder and, in the same patient, an unusual intraoperative finding of a noncoronary aortic sinus to left atrium fistula after device removal.