YEAR IN CARDIOLOGY SERIES
The year in congenital heart disease
Thomas P. Graham, Jr, MD, FACC*,*
* Ann and Monroe Carell Family Professor of Pediatric Cardiology, Vanderbilt Children's Hospital, Nashville, Tennessee, USA
Manuscript received March 25, 2004;
accepted April 9, 2004.
* Reprint requests and correspondence: Dr. Thomas P. Graham, Jr., D2220 Medical Center North, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
tom.graham{at}vaderbilt.edu
As has been noted the other authors of this series, it is a daunting if not impossible task to include all of the relevant advances in congenital heart disease during the last 12 months. I apologize in advance to those whose articles I may have missed. It is an exciting time in the field with an ever-evolving improvement in management for a continuing complex group of patients.
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Surgery and follow-up
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Hypoplastic left heart syndrome.
The latest modification of the Norwood stage I operation uses a right ventricular(RV)-pulmonary artery (PA) shunt instead of the standard aortic pulmonary shunt. Theoretically, the RV-PA shunt will provide a more stable pulmonary circulation along with higher aortic diastolic pressure to improve coronary blood flow. Sano and et al. (1) reported 17 of 19 survivors with two infants <2 kg. Pizarro et al. (2) compared 36 consecutive patients undergoing stage I palliation with an RV-PA conduit with 20 patients who received a standard Blalock-Taussig shunt. They reported more favorable postoperative hemodynamics with higher aortic diastolic blood pressure, improved operative survival of 92% versus 70%, and less need for ventilatory manipulations to balance Qp/Qs in the RV-PA conduit group. Many centers have switched to this modification for first-stage palliation of this complex condition. Although a deleterious effect of the ventriculotomy in the systemic ventricle at an early age is a possible disadvantage of this approach, to date there is no documented evidence for an increased incidence of this complication.
Ghanayem et al. (3) presented the results of a home surveillance program for patients who were discharged after first-stage Norwood palliation. The program included a daily log of weight and arterial oxygen saturation with instructions to contact their physician if their oxygen saturation was <70%, acute weight loss of >30 g in 24 h, or failure to gain at least 20 g during a 3-day period. There was improvement in mortality, and others have attempted to practice such an intensive surveillance program. These patients appear to be vulnerable to early morbidity and mortality between stage I and the more stable stage II superior cava to pulmonary artery shunt, which is performed at approximately three to six months of age. Interstage mortality may be related to suboptimal coronary artery flow reserve and possibly shunt narrowing or thrombosis. The documentation of the actual cause of interstage mortality is still unclear in the majority of patients.
Against this background, Ashburn et al. (4) reported outcomes for the Norwood operation in 710 neonates with critical aortic stenosis or aortic atresia as a part of the Congenital Heart Surgeons Society prospective study. Overall survival was 72%, 60%, and 54% at one month, one year, and five years, respectively. Risk factors of early death include lower birth weight, smaller ascending aorta, and older age at operation. Other variables affecting outcome appear to be a low number of operations at a center, shunt originating from the aorta, and longer circulatory arrest time. These studies from a large number of institutions in the U.S. and Canada are valuable to spot trends and associated risk factors for survival that may be eliminated with different management strategies.
Pulmonary atresia with ventricular septal defect/tetralogy of Fallot.
Pulmonary atresia with ventricular septal defect represents another complex group of patients with extremely variable anatomy. Gupta et al. (5) reviewed a retrospective series of 104 patients treated with staged repair. The 10-year mortality was 16.5% but only 58 of 104 patients achieved complete repair. The number of collateral vessels incorporated into the repair was a risk factor for death. These patients require meticulous management, and those with hypoplastic pulmonary arteries with multiple aortopulmonary collateral arteries can be difficult to manage. Close collaboration between surgeons and interventionalists is required to achieve optimal results.
Duncan et al. (6) reported 46 consecutive patients with staged repair of pulmonary atresia and major aortopulmonary collateral arteries. The Melbourne shunt was used for initial palliation for patients with a central pulmonary artery. Twenty-seven patients subsequently underwent complete repair with a median of three total operations, and 18 additional patients are considered candidates for eventual repair. The staged repair is used by most institutions. Others have suggested that many of these patients may be candidates for early one-stage repair. Direct comparison of these two strategies would be extremely valuable, although the complex and variable anatomy makes it difficult to match patient groups.
Abella et al. (7) report on primary repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals with a radical new approach used in five patients with a median age of 29.6 months. They excluded the descending thoracic aortic segment from which all major aortopulmonary collateral arteries originate and connected this aortic segment with the native pulmonary artery using an interposition polytetrafluoroethylene conduit. The ventricular septal defect (VSD) was closed in all patients, and the RV was connected to the unifocalized pulmonary artery with a valved conduit. All patients survived and during follow-up (12 to 21 months); no patient required additional interventions. This extraordinarily different approach has potential application in a number of patients. The downside is that one is dealing with a long conduit from the RV leading to deep in the chest that will have to be replaced at a later age. In addition, the segment of the descending aorta that is replaced with a conduit also will be small and require further bypass grafting later in life to prevent coarctation. Nevertheless, this is a radial new approach that may prove useful for a number of patients with this anomaly.
Murphy et al. (8) report successful early recruitment of congenitally disconnected pulmonary arteries. Although this report represents a small number of patients, it's a reminder that searching for disconnected pulmonary arteries early and making sure they are included in eventual repair is an important aspect of management.
Kanter et al. (9) report an experience in 56 patients using a freestyle porcine aortic root for valve reconstruction of the RV outflow tract in patients with conotruncal abnormalities. Early results revealed mild or no pulmonary insufficiency in 93% and a calculated mean peak systolic gradient of only 22 mm Hg.
Dearani et al. (10) report late follow-up of 1,095 patients undergoing ventricle to pulmonary artery conduits for the correction of complex cardiac anomalies. Early mortality decreased from 23% before 1980 to 3.7% for the most recent decade. Actuarial late survival for early operative survivors at 10 and 20 years was 77% and 60%, respectively. Freedom from reoperation for conduit failure at 10 and 20 years was 56% and 32%, respectively. These data indicate that the homograft was superior to the porcine valve Dacron conduit in terms of durability. Quality of life is excellent for most patients despite the need for reoperation. The quest continues for an optimal RV-PA conduit.
Boudjemline et al. (11) report an experimental study with percutaneous pulmonary valve replacement in a large RV outflow tract. This group has previously performed percutaneous pulmonary valve replacements in patients with a RV outflow tract  22 mm in diameter. Many postoperative patients have larger outflow tracts with severe pulmonary insufficiency that could be treated by percutaneous valve replacement if a larger expandable stent could be developed. Therefore, they have used a nitinol stent in the shape of a conduit with a central restriction containing an 18-mm bovine valve. Eight of 10 devices were delivered and were functioning properly at two months in a chronic group of ewes. This bold new technology (Figs. 1A and 1B) has the potential for use in a large number of patients. Hopefully, this methodology will be feasible for patient use in the next three to five years.
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Figure 1 (A) The newly designed stent is shown uncovered. The extremities have a diameter of 30 mm, whereas the central part is 18 mm. (B) A polytetrafluoroethylene membrane is covering the stent to ensure sealing of the device. Reprinted from Boudjemline et al. (11).
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Niwa et al. (12) report progressive aortic root dilatation in adults late after the repair of tetralogy of Fallot. These authors had data on 216 patients and identified 32 patients with a mean age of 36 years who had root dilation >50% of expected size. Patients with root dilatation had a higher incidence of pulmonary atresia, right arch, longer shunt to repair interval, and more frequent conduit repair than patients without root dilatation. Aortic valve replacement with root repair was required in 2 of 32 patients. These patients require follow-up not only for pulmonary valve insufficiency and possible pulmonary valve replacement but also for aortic root dilation, which also may need treatment.
Nollert et al. (13) report risk factors for sudden death in 15 of 658 patients who had tetralogy repair at one institution at a median age of 12 years. Risk factors for sudden death were use of an outflow tract patch, male gender, no previous palliation, and higher preoperative New York Heart Association status. The risk of sudden death appears to have decreased with more recent survivors. There is still debate about what cardiac studies are needed in both symptomatic and asymptomatic patients after tetralogy repair. Those patients with significant hemodynamic pressure or volume overload and ventricular or atrial arrhythmias deserve special attention with attempted surgical or interventional treatment of the hemodynamic problems. An electrophysiologic evaluation and management of their arrhythmia either with ablation procedures at catheterization or at the time of surgery frequently is required.
There are an increasing number of postoperative patients with significant pulmonary insufficiency, RV volume overload, and slow deterioration of RV function. Warner et al. (14) report on 36 patients age 15 years who underwent pulmonary valve implantation 12 years after tetralogy repair with additional procedures. All patients had clinical improvement in exercise capacity. There was a 30% reduction in RV diameter. There were two patients who required conduit replacements at one and nine years. There is still no clear-cut indication as to when to intervene. When RV function is significantly impaired with an ejection fraction in the mid-to-low 30s, improvement in the RV volume but not in ejection fraction usually takes place. Earlier rather than later intervention is probably the new order of the day. Because most current conduits/grafts for pulmonary valve replacement have a half-life of only 10 years, this is a difficult decision to make in young patients.
d'Acoz et al. (15) report on a comparison of 44 patients who had a pulmonary commissurotomy for isolated pulmonary stenosis with 189 patients who had transventricular repair of tetralogy of Fallot. Patients had similar degrees of pulmonary insufficiency. Freedom from adverse events related to RV dilation was far better, however, in patients with isolated pulmonary stenosis and commissurotomy. Pulmonary insufficiency is not the only determinant of late symptomatic RV dilation after tetralogy repair. This complication is more deleterious in tetralogy patients who have had right ventriculotomies, causing damage to the RV outflow tract.
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Transposition of the great arteries (TGA)
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Pasquali et al. (16) performed a meta-analysis regarding coronary artery pattern and outcome of arterial switch operation. Overall, this operation has been a resounding success. Debate continues about whether or not unusual coronary artery patterns have added mortality. This analysis showed that patients with common variants have no added mortality but those with intramural or single coronary arteries have significant added mortality that has persisted over time. Because these uncommon variants occur so infrequently the demonstrated added mortality is not surprising.
Wetter et al. (17) reported results of arterial switch operation for correction of 27 patients with the Taussig-Bing anomaly. Twenty-one patients had primary correction with one hospital death and one late death. These authors believe that this anomaly should be corrected in early infancy by VSD closure and simultaneous correction of associated defects. Pulmonary artery banding may lead to significant aortic insufficiency with a two-stage repair.
Formigari et al. (18) report the prevalence and predictors of neoaortic regurgitation after arterial switch operation. There were 61 of 173 patients who had evidence of valvular incompetence, which was progressive in 14 cases and led to surgery in two cases. Multivariant analysis revealed the onset of valvular regurgitation was correlated with the trap-door technique for coronary reimplantation. These authors now recommend the punch technique for repair for all but the most complicated coronary artery patterns. Although significant aortic regurgitation is rare, it is more common with longer follow-up. Neoaortic roots are increased in size in the majority of patients.
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Congenitally corrected transposition of the great arteries (CCTGA)
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Devaney et al. (19) reported results of combined arterial switch and Senning operation for CCTGA. Pulmonary artery banding was used in 15 of 23 patients either for left ventricular (LV) retraining or for congestive heart failure, which was unsuccessful in two because of LV dysfunction. Four patients with banding are currently awaiting repair and eight patients had double-switch operation without banding. One patient required cardiac transplantation for progressive LV failure. There were no surgically acquired arrhythmias or residual significant hemodynamic conditions. All patients are alive and well with a mean follow-up of 36 months.
Langley et al. (20) reported 54 patients with either CCTGA or atrioventricular discordance with double-outlet RV who had anatomic repair. This comprised a Senning procedure plus arterial switch in 29 cases, Senning plus a Rastelli procedure in 22 cases, and Senning plus intraventricular rerouting in 3 cases. The PA banding was used in 9 of 29 cases or 31%. Survivals were 94% at one year and 90% at nine years. Six have acquired LV dilatation or impaired systolic ventricular function. Four patients in the double switch-group have moderate aortic regurgitation and two required valve replacement. Excellent functional status was achieved in the majority of patients.
The complex operation or series of operations appears to work in the majority of patients although it is a formidable challenge. Most patients beyond childhood do poorly with PA banding for LV training. More data are needed to determine when to intervene. The best candidates are those with relatively mild dysfunction at an early age. It is difficult send these patients to surgery when they are clinically well, although the long-term outcome frequently is that of progressive ventricular dysfunction, atrioventricular valve regurgitation, and congestive heart failure.
Of further importance for the patient with CCTGA is an article by Bengel et al. (21), which demonstrated impaired myocardial blood flow reserve of the anatomic RV in the absence of ischemic symptoms. This impairment of flow may be associated with reduced ventricular function of the systemic RV as has been suggested by other investigators. Variations in coronary flow reserve may explain individual differences in ventricular function in adults with CCTGA. Future studies in this area could help in risk stratification for progressive ventricular dysfunction and thus earlier intervention in selected patients.
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Univentricular heart/fontan palliation
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Caspi et al. (22) report on the effect of controlled antegrade pulmonary blood flow and cardiac function after bidirectional cavopulmonary anastomosis in 128 patients with a mean age of six months. In group 1, there were 72 patients with restricted flow through a narrowed valve or by adjustment of a pulmonary artery band with a goal of maintaining the mean pulmonary artery pressure <16 mm Hg. In group 2, the cavopulmonary anastomosis was the only source of pulmonary flow. One death occurred. The mean pulmonary artery pressure at the end of operation was not different between groups. Patients in group 1 had higher oxygen saturation and a shorter mean hospital stay than patients in group 2. There were no late deaths during the mean follow-up of 36 ± 10 months. Oxygen saturation remained higher and the hematocrit lower in group 1 patients with antegrade pulmonary flow. In addition, total pulmonary artery size was greater in group 1 than in group 2. Controlled antegrade pulmonary flow may have a favorable effect on cardiac function, oxygen saturation, and pulmonary artery growth.
Chun et al. (23) reviewed records on 166 patients who underwent hemi-Fontan and Fontan procedures during a 13-year period at a single institution to determine risk factors for stroke. The overall incidence for stroke of 5.5% for the first and final stage palliation was comparable with earlier reports. Stroke occurred more often in the first 12 months after surgery, but risk for stroke extended to more than nine years after operation. Pulmonary artery banding was related to stroke risk. Six of the nine stroke patients were either on aspirin or aspirin plus warfarin.
Seipelt et al. (24) report on thromboembolic complications in 101 patients who underwent a Fontan-type procedure. Mean follow-up was 5.7 years. Thromboembolic events occurred in 15.3%. The type of operation as well as other known risk factors had no influence on the rate of thromboembolism. During the first postoperative year, 7 of the 13 events occurred. The second peak developed 10 years later. Patients benefited significantly from warfarin compared with those who did not receive any medication. These authors propose that warfarin should be used in these patients. The small numbers of patients studied and lack of prospective data do not definitely support this proposal. Nevertheless, these patients need to be observed frequently for potential thromboembolic events and some type of antithrombotic therapy used. Whether warfarin will prove to be superior to aspirin is unclear. Other anti-thrombolic management strategies may prove useful as these become available.
Michielson et al. (25) report on 43 patients who underwent 44 orthotopic heart transplants for complex transposition, double-outlet RV, single ventricle, and other end-stage structural heart disease. Hypoplastic left heart syndrome diagnosis and failing Fontan were independent risk factors of early mortality by regression logistic modeling.
Although the Fontan stage represented the only predictor of overall mortality, the 10-year survival for all patients was 54%. Orthotopic heart transplants for structural congenital heart disease with single ventricle physiology entails substantial early mortality and bidirectional cavopulmonary anastomosis enables the best transition to transplant. A transplant should be considered in the decision-making process for Fontan completion in all high-risk candidates. It remains difficult to choose which management strategy to follow in high-risk patients. Patients with congenital heart disease overall have approximately a 50% survival at 12 years for orthotopic heart transplants. Obviously, choosing patients who are relatively more stable other than the end-stage edematous Fontan patient will improve overall outcome at least in the short-term.
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Surgery: outcome and follow-up
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Monro et al. (26) report a retrospective analysis of 1,220 consecutive children younger than 16 years of age who underwent reoperation after primary repair of a congenital heart defect. The overall 30-day mortality was 6.9%; 171 patients had a total of 206 reoperations. Early mortality for the first operation was 10.4% and for the second was 3.8%. These authors give excellent longitudinal data over 20 years regarding reoperation for congenital cardiac defects. These are useful data that every center should have. Although improvements have been made in a number of these conditions, there is nothing like accurate historical data for comparison of current with past success.
Almeida de Oliveira et al. (27) report on extra-anatomic aortic bypass from ascending to descending thoracic aorta for complex aortic coarctation or recoarctation in 18 consecutive patients age 18 to 61 years (with a mean of 32 years). Follow-up was completed in all with a mean of 5.6 years and a range of 12 months to 22 years. No neurologic complications, early or late mortality, late reoperations, or graft complications occurred. Patent grafts were confirmed in all. There are a number of patients with complex coarctations, recoarctations, or hypoplastic aortic arches who are difficult to treat with standard surgical techniques or with catheter interventional methods. Both the ascending aorta to abdominal descending aorta graft and the ascending to descending thoracic aortic graft reported here show promise for relief of complex arch obstructions.
Baskett et al. (28) report on current results for surgical atrial septal defect closure in 100 consecutive patients at a mean age of 60.5 months. There was no mortality, no residual atrial septal defect (ASD), and no neurological complications. There were three cases of postpericardiotomy syndrome and 26 pericardial effusions. The median stay was four days. These surgical results of ASD closure in the modern era provide an excellent gold standard to use for both new surgical and interventional catheterization techniques for ASD closure.
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Cardiac catheterization and interventional techniques
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Fischer et al. (29) report experience with transcatheter closure of atrial septal defects using the Amplatzer septal occluder. There were 236 consecutive patients aged 6 months to 46 years with a median of five years considered for closure. Eighteen defects were considered too large for closure before catheterization, and at catheterization an additional 18 patients did not have the device implanted because the stretched diameter was too large, the device was unstable, the device compromised the mitral valve, the device obstructed the right pulmonary vein, or the patient had additional venous anomalies or a Qp:Qs <1.5. Atrial septal defect closure was successful in 200 patients; 14 had multiple ASDs, and 8 had a septal aneurysm. Severe complications occurred in two cases, including air embolism and retroperitoneal bleeding. At follow-up at a median of 3.3 years, complete closure was documented in 93% with a residual trivial shunt in 12 patients. There continues to be good results reported with this device. With careful patient selection, it can be used in most patients with secundum atrial septal defects.
Thanopoulos et al. (30) report on 10 children, aged 1.5 to 12 years, with a perimembranous ventricular septal defect who underwent transcatheter closure with the Amplatzer asymmetric VSD device. The VSD diameter ranged from 2 to 8 mm. After deployment, there was no residual shunt in 9 of 10 patients. One patient had a trivial shunt that disappeared at three months. Three patients developed transient left bundle branch block; no other complications were observed. This device is potentially useful for closure of perimembranous ventricular septal defects. The question as to when to close small VSDs remains; these authors closed several small defects that would be left alone in most centers. These defects are close to the aortic valve and there are concerns with potential damage to the valve and/or the conduction system. Further data will be needed to determine in whom this device is safe and useful.
Bacha et al. (31) report six patients with percutaneous closure of muscular VSDs without cardiopulmonary bypass, after sternotomy and under transesophageal echocardiographic guidance. The RV free wall was punctured, and a wire was introduced across the defect. The Amplatzer muscular VSD device was then inserted. No complications from using the technique occurred, and discharge echocardiography showed no significant shunt. This technique may be useful in patients with moderately large complex muscular defects which effects can be difficult to find and effectively close surgically.
Humpl et al. (32) report on 30 patients with pulmonary atresia and intact ventricular septum who underwent attempted percutaneous valve perforation and balloon dilatation of the pulmonary valve. Perforation was achieved in 27 patients. This is an effective strategy provided there is a patent infundibulum and a lack of an RV-dependent coronary circulation.
Krumsdorf et al. (33) report on the incidence and clinical course of thrombus formation after patent foramen ovale (PFO) (n = 593) or ASD (n = 407) closure. Transesophageal echocardiography was used for surveillance after four weeks and six months. Thrombus formation in the left atrium (n = 11), right atrium (n = 6), or both (n = 3) was found in 5 of the 407 ASD patients and in 15 of 593 PFO patients. Thrombus was diagnosed in 14 of 20 patients after four weeks and in 6 of 20 patients later on. The incidence was 7% with the CardioSeal device (Nitinol Medical Technologies, Boston, Massachusetts), 5.7% with the STARFlex device (Nitinol Medical Technologies), 3.6% with the ASDOS device (Osypka Corp., Rheinfelden, Germany), 0.8%, with the Helex device (W.L. Gore and Associates, Flagstaff, Arizona), and 0% with the AMPLATZER device (AGA Medical Corp., Golden Valley, Minnesota). A prethrombotic disorder as a possible cause of the thrombus was found in two patients. Postprocedure atrial fibrillation and persistent septal aneurysm (n = 4) were thought to be predictors for thrombus formation. In 17 of the 20 patients, the thrombus resolved under therapy with heparin or warfarin, and in three patients, the thrombus was removed surgically. There appears to be a low but definite possibility of thrombus formation with an ASD device. Most patients are on aspirin therapy for six months or longer after implant and follow-up obtained by history, clinical exam and echocardiography. Surveillance of a large cohort will be needed to clarify the risk of this complication.
Bell et al. (34) report on percutaneous endoluminal repair of aneurysms associated with coarctation in five patients. Ince et al. (35) report percutaneous endovascular stent-graft placement in six consecutive patients (mean age, 49 years) with late aneurysm formation after coarctation repair. Placement of a customized stent-graft was successful with no 30-day or 1-year intervention-related morbidity or mortality. These reports of this nonsurgical treatment of aortic aneurysm post coarctation repair are encouraging.
Duke et al. (36) report efficacy and safety of stent redilation in 60 patients with either coarctation or pulmonary artery branch stenosis. Neointimal thickening >1 mm was detected in 6 of 12 coarctation stents and 9 of 21 stented pulmonary arteries. These authors conclude that neointimal proliferation can be precipitated by overdilating stents at implantation. Redilation using balloons matched to the distal vessel diameter increased lumen size but may not optimize diameter. Redilation is effective whether the indication for redilation is resistant stenosis at implantation, underexpansion at implant, neointimal proliferation, or relative stenosis caused by growth. There was one patient with massive hemorrhage from pulmonary artery rupture distal to stent redilation. This report is encouraging that redilation therapy can be performed with good efficacy.
Gewillig et al. (37) report on stenting the neonatal arterial duct in duct-dependent pulmonary circulation. All stents were deployed with adequate pulmonary flow at early- and midterm follow-up. There were no procedure-related complications. One patient died from sepsis. All patients had relief of cyanosis for three to four months. Here is another methodology to provide adequate pulmonary artery blood flow in patients with relatively short, straight ducts.
Michel-Behnke et al. (38) report on stenting the ductus arteriosus and banding the pulmonary arteries in 20 patients with hypoplastic left heart syndrome. Stenting of the arterial ductal combined with bilateral pulmonary artery banding represents another approach to these patients. The ability to achieve good early palliation and then perform both the Norwood I and II operations in one stage at 3.5 to 6 months has definite theoretical advantages. Whether this will prove feasible in the majority of patients with low morbidity or mortality remains to be seen.
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Neurological complications after cardiac surgery
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Bellinger et al. (39) report on developmental neurological and speech outcomes at eight years of age in 155 of 160 eligible children who had arterial switch for TGA. Patients were assigned either total circulatory arrest or low-flow bypass. Treatments groups did not differ in neurologic status, full-scale or performance IQ score, academic achievement, memory, problem solving, and visual-motor integration. Children assigned to circulatory arrest performed worse on tests of motor function. Assignment to low-flow bypass was associated with a more impulsive response style on a continuous performance test of vigilance and worse behavior as rated by teachers. These studies indicate an overall favorable outcome in the majority of infants undergoing this complex surgery. Although circulatory arrest has been associated with greater functional deficits than low-flow cardiopulmonary bypass, both strategies have an increased risk of neurodevelopmental vulnerabilities.
Gaynor et al. (40) evaluated 244 patients who were <6 months of age undergoing cardiopulmonary bypass for repair of congenital heart defects and evaluated an association between apolipoprotein E genotype and postoperative neurodevelopmental dysfunction. The apolipoprotein E 2 allele was associated with a worse neurologic outcome as assessed by the Psychomotor Developmental Index. This interesting study indicates one reason for the differences in outcomes of patients who have similar postoperative courses. The particular allele associated with worse outcome varies with ethnicity; in this study it accounted for only 13.5% of the cohort.
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Medical therapy
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Feltes et al. (41) report on a randomized double-blind placebo controlled trial, including 1,287 children with congenital heart disease (CHD) randomly assigned to receive five monthly intramuscular injections of palivizumab or placebo for protection from respiratory syncytial virus (RSV) complications. Palivizumab recipients had a 45% relative reduction in RSV hospitalizations, a 56% reduction in total days of hospitalization, and a 73% reduction in total RSV hospital days with increased supplemental oxygen. Adverse events were similar in the treatment groups. This randomized trial shows the benefit in terms of RSV hospitalizations in using intramuscular hyperimmune RSV globulin to ameliorate RSV infections in infants with CHD. Although the use of hyperimmune globulin did not prevent RSV infections, it did lessen the severity of this infection. This treatment is expensive but it is effective and its use has been adopted in a policy statement by the American Academy of Pediatrics Committee on Infectious Diseases.
Hoffman et al. (42) reported on a double-blind placebo controlled trial with three parallel groups regarding the efficacy and safety of milrinone in preventing low cardiac output in infants and children after corrective surgery for congenital heart disease. Among 238 patients, the administration of high-dose milrinone significantly reduced the risk of low cardiac output syndrome compared with a placebo with a relatively risk reduction of 55%. There were two deaths both after infusion of study drug. Both this study and the previous palivizumab study indicate the feasibility of conducting relatively large-scale placebo controlled trials in children with good evidence-based data for subsequent clinical use.
Schulze-Neick et al. (43) intravenous sildenafil in 12 children with CHD and increased pulmonary vascular resistance. Intravenous sildenafil more effectively reduced pulmonary vascular resistance than nitric oxide both in the "cath laboratory" patient group and in the postoperative patients group. Although the vasodilating effects of sildenafil showed pulmonary selectivity, it was associated with intrapulmonary shunting in the postoperative patient. There is an increasing but small armamentarium of medications for use in patients with pulmonary vascular resistance elevation. Both intravenous and oral sildenafil may be efficacious in certain patients with elevated pulmonary vascular resistance.
Ringel and Peddy (44) report the use of spironolactone in patients with protein-losing enteropathy who have had Fontan palliation. These authors studied three patients with protein-losing enteropathy that was resistant to all therapy. Spironolactone in doses from 2.3 to 5 mg/kg/day induced remission for two to three years. Although this report represents a small number of patients, this rare complication is such a serious problem that any new possibilities for treatment are welcome.
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Arrhythmia
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Alexander et al. (45) report the use of implantable cardioverter defibrillator (ICD) therapy in 76 patients <30 years with CHD, primary electrical disease, hypertrophic cardiomyopathy, or idiopathic dilated cardiomyopathy. Transvenous dual-chamber ICDs were implanted in 29 patients. Over a median two-year follow-up, 28% of patients received appropriate shocks, and 25% experienced inappropriate shocks. With multivariate analysis, growth strongly correlated with lead failure. Complications occurred in 29 patients, including lead failure in 29%, ICD "storm" with sequential shocks in 5 patients and infection in 2 patients. No deaths were attributable to ICD placement or device failure. Implantable cardioverter defibrillator therapy can effectively manage malignant arrhythmias in selected patients. Spurious shocks or ICD storm may increase morbidity and emphasize the need for concomitant medical and ablative therapy. The application of ICD therapy to selected pediatric patients remains an evolving strategy. It can be life saving but it is not without its complications.
Zimmerman et al. (46) report acute hemodynamic benefit of multisite ventricular pacing after surgery in 29 patients age 1 week to 17 years with prolonged QRS interval who had atrial and ventricular unipolar epicardial temporary pacing leads placed at surgery. Systolic blood pressure improved in all by a mean of 9.7% and cardiac index improved in 19 of 21 patients with no change in 2 patients. Pacing facilitated weaning from bypass in two patients. Multisite ventricular pacing may be another addition to therapy for the failing heart with a congenital defect. This may be applicable both to biventricular circulation patients and those with a single ventricle.
Strasburger et al. (47) report the use of amiodarone therapy for drug-refractory fetal tachycardia. These fetuses were treated transplacentally with a maternal loading dose of oral amiodarone for two to seven days, followed by daily maintenance therapy for <1 to 15 weeks. Digoxin therapy was continued. Amiodarone or amiodarone combination therapy converted 14 of 15 with SVT. Amiodarone-related adverse effects were transient in five infants and eight mothers. Mean gestational age at delivery was 37 weeks with 100% survival. Orally administered maternal amiodarone therapy can be a safe and effective treatment for drug-refractory fetal tachycardia even when accompanied by hydrops fetalis or ventricular dysfunction.
Gaita et al. (48) report six patients from two families who submitted to extensive work-up because of syncope, palpitations, and resuscitated cardiac arrest in the presence of a positive family history for sudden death. Electrocardiograms exhibited a QT interval 280 ms (QTc 300 ms). During electrophysiological study, short atrial and ventricular refractory periods were documented in all and increased ventricular vulnerability to fibrillation in three of four patients. This short QT syndrome is characterized by familial sudden death, short refractory periods, and inducible ventricular fibrillation. It is important to recognize this electrocardiographic pattern because it is related to a high risk of sudden death in young, otherwise healthy subjects.
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Genetic causes of CHD
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Muncke et al. (49) report missense mutations and gene interruption in Prosit240, a novel Trap240-like gene, in patients with TGA. Garg et al. (50) report GATA4 mutations causing human congenital heart defects and revealed an interaction with TBX5. These two articles represent part of a rapidly developing body of knowledge regarding genetic causes of congenital heart disease, heretofore unexpected. The knowledge base in this area keeps expanding and it remains difficult to keep current.
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Adult CHD
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Silversides et al. (51) report on findings in 34 patients age 42 ± 10 years with Eisenmenger's syndrome who underwent computed tomograph angiograms to determine the incidence of pulmonary thrombosis. The prevalence of proximal pulmonary artery thrombus was 21% and more distal thrombus was observed in 43% of the patients who had thrombus in proximal pulmonary arteries (Fig. 2). The patients with thrombus were more likely to be female and to have lower oxygen saturations. Difference in functional status did not identify patients at high risk. Unfortunately, warfarin anticoagulation can lead to severe bleeding in these patients who are prone to develop hemoptysis. Thus, this strategy is fraught with difficulty, and the risk-benefit of prophylactic warfarin therapy remains unclear.
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Figure 2 (A) Axial computed tomography angiography image at the level of the main pulmonary arteries demonstrates severe dilation, with the main pulmonary artery measuring 71 mm. There is an associated eccentric irregular thrombus in the left main artery (short arrows). A tiny focus of calcification is noted in the posterior wall of the right pulmonary artery (long arrow). (B) Axial image at the level of lung bases showing extension of the thrombus into the segmental basal arteries of the left lower lobe (short arrows). Reprinted from Silversides et al. (51).
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Connolly et al. (52) report cranial magnetic resonance angiographic study in 100 patients with coarctation of the aorta to detect intracranial aneurysms. The frequency was significantly higher than that predicted in the general population (10% vs. 2%). No clinical or geographical differences were found between patients with coarctation and aneurysms and patients with coarctations and no aneurysms. These authors suggest that noninvasive cerebral imaging to screen for aneurysms should be considered in patients with coarctation.
Silversides et al. (53) report on the early and intermediate term outcomes of pregnancy with congenital aortic stenosis in 49 pregnancies in 39 women. Only patients with severe aortic stenosis with a peak gradient  64 mm Hg or aortic valve area 1 cm2 experienced maternal complications, including 2 of 29 with pulmonary edema and 1 of 29 with atrial arrhythmias. There were no maternal deaths, and there were no fetal or neonatal deaths. There were five premature births. This series is encouraging in regard to the ability of women with moderate aortic stenosis and in most cases, even with severe stenosis to tolerate pregnancy. There was a high incidence of surgical intervention after pregnancy in women with severe aortic stenosis, and one should consider of aortic valve intervention before pregnancy in these patients.
Vogel et al. (54) report on systemic ventricular function in patients with transposition of the great arteries after atrial repair. These authors examined 55 controls and 80 patients with a mean age of 22 years who had undergone atrial repair at the age of 8 months with a range of 0.3 to 72 months. Right ventricular systolic function was derived by analysis of pressure-volume relationships at rest and during dobutamine stress. In the group as a whole, isovolumic myocardial acceleration was reduced compared with the subpulmonary RV and the systemic LV of controls. There was abnormal wall motion in 44 patients, which was associated with reduced isovolumic myocardial acceleration. Diastolic velocities were also abnormal but unrelated to the presence of wall motion abnormalities.
Studies of the systemic RV continue to show abnormalities both in the laboratory and clinically as a function of age. We will need all of the therapeutic armamentarium for treatment of congestive failure for the increasing number of patients with systemic RVs who have had successful surgical intervention in the past.
Prasad et al. (55) assessed the role of contrast enhanced three-dimensional magnetic resonance angiography (MRA) as a minimally invasive technique to allow detailed studies in a single breath-hold for adult patients with major aortopulmonary collateral arteries and partial anomalous pulmonary venous drainage. This modality was used in 29 consecutive patients with a diagnosis of multiple collateral pulmonary arteries (n = 16) and partial anomalous pulmonary venous drainage (n = 13). There was excellent correlation between the MRA and cardiac catheterization, echocardiography, and surgical inspection. Additional information was gained for patients with major aortopulmonary collateral arteries on confluence and size of pulmonary arteries, pulmonary artery stenosis aneurysmal dilatation of the pulmonary artery and additional vascular abnormalities. Shunt assessment, in cases without shunt (9 of 16 patients), showed patency in all cases. For adults with partial anomalous pulmonary venous drainage, further information was obtained on drainage origin in 11 of 13. There were no complications. Both MRA and rapid computed tomograph can provide outstanding images for complex conditions such as these. These can be extremely helpful prior to surgery or planned catheter intervention.
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Surgery and follow-up
Transposition of the great...