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J Am Coll Cardiol, 2005; 45:9-11, doi:10.1016/j.jacc.2005.05.012 © 2005 by the American College of Cardiology Foundation |
Children’s Hospital and Brigham and Women’s Hospital, Boston, Massachusetts
* Reprint requests and correspondence: Dr. Thomas L. Spray, Children’s Hospital of Philadelphia, Chief, Cardiothoracic Surgery, 34th & Civic Center Boulevard, Suite 8527, Philadelphia, Pennsylvania 19104. (Email: spray{at}email.chop.edu).
Three abstracts were selected for featured poster presentations in the Pediatric Cardiology/Adult Congenital Heart Disease Sessions. A study by Veldtman et al. (1) from Southampton, United Kingdom, evaluated long-term unsuspected hepatic injury in patients who underwent the Fontan operation. Seven patients who were evaluated for Fontan conversion late after the Fontan operation showed striking changes of congestion, fibrosis, and cirrhosis on liver biopsies, despite preservation of synthetic hepatic function on routine blood testing. Importantly, the changes in the liver did not correlate with resting hemodynamics. These findings are concerning and suggest that in the older patient with congenital heart disease, potential for functional incapacity due to non-cardiac etiologies must be considered. The demonstration of serologically unsuspected hepatic inflammation in older patients after the Fontan operation recognizes the potential for increased morbidity. It is not clear, however, whether the findings are applicable to all patients with the Fontan circulation, because the population examined in this study were patients being considered for Fontan take-down.
Much interest is present in alternatives to radiographic imaging to decrease procedural risk, as well as to improve physiologic measurements during diagnostic evaluation or intervention. A second featured poster by Telep et al. (2), from the National Heart, Lung, and Blood Institute of the National Institutes of Health, evaluated real-time magnetic resonance imaging (MRI)-guided coarctation stent repair in an animal model. In a swine model of coarctation stenting, the gradient was reduced and follow-up catheterization and necropsy showed durable results. The investigators noted that an active antenna guidewire shortened the procedure time compared with passive nitinol guidewires by improving stent visualization. They concluded that stent delivery for aortic coarctation, entirely using real-time MRI with commercially available devices is feasible. This study is provocative and may presage the use of MRI for interventional techniques in the near future.
A third featured poster by Heistein et al. (3), from the University of Texas Southwestern Medical Center and Children’s Medical Center in Dallas, evaluated a cross-sectional study of 80 children receiving aspirin for various indications, including both cyanotic and acyanotic children with congenital heart disease. The authors found that almost one-third of these patients had aspirin resistance, which was not due to a lack of inhibition of platelet thromboxane production, suggesting that alternative sources of thromboxane and thromboxane-independent mechanisms, such as adenosine triphosphate-induced platelet activation, may contribute to aspirin resistance in this population. This demonstration of potential aspirin resistance highlights the importance of non-anatomic vascular and circulatory factors in older individuals with congenital heart disease.
Several abstracts evaluated the use of B-type natriuretic peptide (BNP) as a useful bedside screening marker for various hemodynamic effects. One study by Sanjeev et al. (4) from the Children’s Hospital of Detroit, Michigan, suggested that plasma BNP levels are useful bedside screening tests for abnormal cardiac function and anthrocylcline-induced cardio-toxicity. Another study by the same author (5) used BNP as a screening tool for diagnosis and treatment of hemodynamically significant patent ductus arteriosus. Patients with BNP levels over 70 pg/ml were noted to have hemodynamically significant patent ductus arteriosus, which may improve decision making regarding medical and surgical therapy to close the ductus in premature infants.
A further study by Connolly et al. (6) from New York University suggested that BNP levels have diagnostic value in children with heart failure. A BNP level of 100 pg/ml is suggestive of heart failure, whereas a level >400 pg/ml is suggestive of a critical threshold for risk of mortality and/or morbidity. A fourth study by Brili et al. (7) from Athens, Greece, suggested that BNP levels correlate with right ventricular dilation in tetralogy of Fallot, suggesting a non-invasive way of evaluating the changes in right ventricular dilatation over time.
Several studies looked at nesiritide as a new agent for use in children with congestive heart failure. Studies by Mahle et al. (8) from Atlanta, Georgia, and Jefferies et al. (9) from Baylor College of Medicine in Houston, Texas, showed that nesiritide infusions in children with congestive heart failure improved natriuresis and diuresis and improved, in addition, appetite and functional status, adding a new drug to our armamentarium in children to treat congestive heart failure, either in anticipation of or in order to preclude cardiac transplantation.
Several notable abstracts were presented in the Congenital Heart Disease Surgery and Interventional Cardiology sessions. Chang et al. (10) from Los Angeles, California, recognized female gender to be associated with 18% higher in-hospital mortality after congenital heart defect repair. It was not clear from the abstract whether the mortality was lesion-specific. The accrued mortality rates were not statistically different between genders, but fewer neonatal operations and lower-risk procedures were noted in the female population studied. The author’s also noted that low-volume hospitals had higher mortality than high-volume hospitals for both genders. A study by Fedderly et al. (11) from Milwaukee, Wisconsin, noted that in a series of 72 patients with hypoplastic left heart syndrome, aortic valve atresia was associated with increased mortality only in the presence of a patent mitral valve. This study suggests that the hypertensive left ventricle adds a risk factor to both in-hospital mortality, 30-day mortality, and survival to stage II palliation.
Singh et al. (12) from Washington University in St. Louis, Missouri, evaluated patients with single left ventricle by MRI more than 10 years post-Fontan procedure and noted that segmental and diffuse myocardial fibrosis and scarring was common, suggesting that fibrosis may contribute to abnormal contractile mechanisms, possibly resulting in impaired ventricular systolic function and diastolic dysfunction, which can affect long-term outcomes in these patients.
Another study from Davis et al. (13) from the Children’s Hospital of Philadelphia, evaluated exercise performance after pediatric heart transplantation. The findings of this study suggested that exercise performance is impaired after transplant and continues to decline over time. This decreased performance is largely related to diastolic dysfunction rather than a decrease in systolic function.
Interventional catheterization sessions included the presentation of a multicenter evaluation of the Helex atrial septal occluder device (W.L. Gore & Associates, Flagstaff, Arizona). The abstract by Jones et al. (14) from Seattle, Washington, included results from 14 U.S. sites and showed that the Helex septal occluder compares favorably to surgical repair, with reduced anesthesia time and reduced hospital stay.
A study by Marshall et al. (15) from Boston, Massachusetts, looked at the technical aspects of fetal aortic valve dilation. They reported technical success in 20 of 26 fetuses between 21 and 31 weeks’ gestational age. The authors noted a balloon/annulus ratio of 1.1 to 1 resulted in improvement of antegrade flow; however, at least moderate aortic regurgitation occurred in 25% of cases. The aortic regurgitation appeared to be well tolerated and improved over time, suggesting that the stenotic fetal aortic valve responds in a unique fashion to balloon valvuloplasty.
The adult congenital heart sessions included an abstract by Diller et al. (16) from London, United Kingdom, showing chronotropic incompetence is prevalent in patients with single ventricle physiology and is associated with reduced exercise capacity. These findings suggest that implantation of rate-responsive pacemakers could offer functional benefits to these patients.
This summary includes only a portion of the highlights of the pediatric cardiology and congenital heart disease sections of American College of Cardiology 2005 Annual Session. The application of new technologies and the continued evaluation of long-term outcomes in children with complex congenital heart disease as they age into adulthood continue to provide important new information and areas for further investigation.
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