YEAR IN CARDIOLOGY SERIES
The Year in Congenital Heart Disease
Thomas P. Graham, Jr, MD, FACC*
Division of Pediatric Cardiology, Vanderbilt Children's Hospital, Nashville, Tennessee
Manuscript received July 5, 2008;
accepted August 4, 2008.
* Reprint requests and correspondence: Dr. Thomas P. Graham, Jr., Division of Pediatric Cardiology, Vanderbilt Children's Hospital, 2200 Children's Way, Suite 5230, Nashville, Tennessee 37232-9119 (Email: tom.graham{at}vanderbilt.edu).
Key Words: congenital • heart • disease
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Long-Term Management of Tetralogy of Fallot (TF)
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Articles related to long-term management of the status of older children and young adults after repair of TF include issues related to assessment of pulmonary regurgitation and timing pulmonary valve replacement as well as indications for and results of implantation of defibrillators.
Gengsakul et al. (1) report a matched cohort study of 82 patients with pulmonary valve replacement (PVR) after TF repair without a history of ventricular arrhythmia who were compared with non-PVR control subjects. Oxygen consumption at peak exercise did not change in either group. For PVR subjects, there was a significant reduction in pulmonary valve regurgitation (PR), tricuspid valve regurgitation (TR), and right ventricular (RV) size and dysfunction on echocardiography. Symptoms and functional class improved after PVR, but a change in arrhythmia was not detected. There were no sudden deaths in the PVR subjects, whereas 4 patients died suddenly in the non-PVR group.
Meijboom et al. (2) report on 67 patients who were followed from 15 ± 3 years until 27 ± 3 years after TF surgery. Twenty-two patients had mild-to-moderate PR, and no significant changes occurred during follow-up. Of 45 patients with severe PR and severe RV dilation, 28 (62%) remained free of symptoms and did not undergo PVR. No additional changes in RV size or exercise capacity were found. Seventeen patients had symptoms and underwent PVR; 9 of 17 improved clinically and echocardiographically, and QRS duration shortened. Refraining from PVR in asymptomatic patients led to no measurable deterioration in 25 of 28 patients. Referring symptomatic patients for PVR led to improvement in 9 of 17 patients. This article highlights the dilemma in following asymptomatic patients with significant PR. Although most showed no measurable deterioration, in 24% there were questionable or unsatisfactory results for this type of management.
Henkens et al. (3) analyzed the influence of pre-operative PR severity and RV size and function on outcome in 27 adults who had cardiac magnetic resonance imaging (MRI) before and after PVR. PR was not related to RV dimensions or function before PVR, and severity of PR did not influence changes in RV dimensions after PVR. These data suggest that the timing of PVR should be based on indexed RV end-systolic volume and corrected RV ejection fraction (EF) rather than severity of PR. It is unclear how PR cannot be related to RV dimensions in this article. Nevertheless, the preceding 3 reports emphasize that diligence is needed in follow-up of these patients and MRI, plus exercise studies can help in providing optimal timing for PVR before deterioration of RV function occurs. This can be a difficult enterprise despite all of our efforts. If we had a perfect valve it would be much easier, but such is not the case.
Khairy et al. (4) report on implantable cardioverter-defibrillators (ICDs) in TF patients. A total of 121 patients were enrolled and followed for a median of 3.7 years. The ICDs were implanted for primary prevention in 68 patients and for secondary prevention in 53, defined by clinical sustained ventricular tachycardia (VT) or resuscitated sudden death. Overall, 31% received at least 1 appropriate and effective ICD discharge; actuarial rates of appropriate shocks were 7.7% and 10% for primary and secondary prevention, respectively. A higher left ventricular (LV) end-diastolic pressure and nonsustained VT independently predicted appropriate ICD shocks in primary prevention. Inappropriate shocks occurred in 6% of patients yearly. Additionally, 36% experienced complications, of which 5% were acute, 21% were late lead-related, and 6% were late generator-related. Nine patients died: an annual mortality of 2% that did not differ between primary and secondary groups. Patients with TF and ICDs for primary and secondary prevention experience high rates of appropriate and effective shocks; however, inappropriate shocks and lead-related complications are common. ICDs remain the last resort before transplantation in attempting to prevent sudden death in patients with severe cardiovascular disease who are at risk. Complications remain a factor in using this modality, and experienced physicians must weigh carefully the good and the bad of this modality in TF patients before using it. The ICD use in selected TF might prove beneficial for primary prevention, but guidelines for use in this situation are still unclear.
Hoohenkerk et al. (5) report 28 years of experience with transatrial-transpulmonary repair of 20 patients with atrioventricular septal defect with TF. Five patients had prior shunts. All repairs were accomplished without a conduit. The 2-patch technique was used to correct the atrioventricular septal defect. There was no in-hospital mortality and 1 late, noncardiac death. Six patients required 8 reoperations: 6 for atrioventricular (AV) valve insufficiency, 1 for residual ventricular septal defect (VSD), and 1 for pulmonary artery branch obstruction. Follow-up showed all 19 patients in good clinical condition without medication. Echocardiography revealed good RV function, low RV outflow tract gradient, and trace PR.
These results of transatrial-transpulmonary repair of AV septal defect with TF are outstanding and, hopefully, can be duplicated by others. It will be of interest to assess post-repair patients with exercise studies and MRI.
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Fontan Surgery
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Ongoing important studies continue to seem related to post-Fontan natural history, methods of Fontan repair, flow dynamics, and evaluation before and after Fontan repair.
Khairy et al. (6) report on 261 adults who had Fontan surgery at a median age of 8 years. Perioperative mortality gradually decreased with time with 93% freedom from death or transplantation at age 10 years, 83% at 20 years, and 70% at 25 years. Thromboembolic death risk increased 15 years after surgery as predicted by clinically identified thrombus and lack of aspirin or warfarin therapy. Independent risk factors for heart failure mortality were single RV morphology, higher post-operative right atrial pressure, and protein-losing enteropathy (PLE). Incidence of sudden death was 0.15%/year with most events presumed arrhythmic. Hopefully, patients operated at a younger age having a lateral tunnel or extracardiac connection will have less evidence of cardiac dysfunction and do better in the long-haul. Nevertheless, this is not a rosy picture for all of those patients with hypoplastic left hearts and systemic RVs who have had or will have Fontan surgery.
d'Udekem et al. (7) report on 305 consecutive patients who underwent a Fontan procedure with 10 hospital deaths (3%) and no death after 1990. Independent risk factors for mortality were elevated pulmonary artery pressure and common AV valve. Twenty-year survival was 84%. Recent techniques improved late survival. The 15-year survival after atriopulmonary connection was 81% versus 94% for lateral tunnel patients. Nine patients required heart transplantation. Freedom from Fontan failure was 70% at 20 years. After extra-cardiac conduits were used, death, supraventricular tachycardia, or failure was not noted. Although the Fontan procedure remains palliative, patient selection and improved techniques have minimized hospital mortality. There is increasing rationale for converting an atrial pulmonary connection to an extracardiac connection early in patients with increasing symptomatology. The patients in this report with lateral tunnel or extracardiac connection operated at an earlier age had less arrhythmia, less operative mortality, and are likely to have failure of their Fontan circulation delayed considerably and hopefully in many cases prevented.
Nakano et al. (8) report on 292 patients who underwent extracardiac conduit total cavopulmonary connection at an average age of 5.8 years, with 126 patients followed for more than 5 years. There was 1 operative death and 6 late deaths. Actuarial survival rate was 95% and 94% at 5 and 10 years, respectively. Seven patients had late complications, including new onset atrial arrhythmias in 3 patients, PLE in 2, thromboembolism in 1, and bleeding complication in 1 patient. Seven patients underwent reoperation not related to the conduit. Freedom from Fontan-related events was 89% at 5 years and 85% at 10 years. Late cardiac catheterization showed low central venous pressure of 10 mm Hg, cardiac index normal at 3.6, and arterial oxygen saturation of 95%. No patients showed conduit stenosis. Exercise performed on 101 patients showed endurance times of 76% of normal, peak heart rate 92% of normal, and peak oxygen consumption 90% of normal. There was a low incidence of systemic ventricular dysfunction with EF mildly reduced in 16%, moderately reduced in 2%, and severely reduced in only 1 patient by echocardiographic evaluation. These authors used warfarin plus aspirin in all patients and feel that this might contribute to their excellent outcomes.
Calvaruso et al. (9) report 4-year follow-up of 246 patients from 3 institutions, with restrictive but not critical antegrade pulmonary blood flow who received a bidirectional cavopulmonary shunt with continued additional forward pulmonary blood flow; 208 or 85% underwent bidirectional cavopulmonary anastomosis as primary palliation, and 38 patients with previous pulmonary artery banding or other palliation were also enrolled. None had a systemic-to-pulmonary shunt. No in-hospital deaths occurred. During the observational period, 30% of patients who were considered optimal candidates underwent Fontan completion for increased cyanosis and/or hematocrit and/or fatigue with exertion. Three patients expired after total cavopulmonary connection, a 4% mortality rate. The remaining 173 patients are alive with initial palliation, and all patients are well-palliated with an arterial oxygen saturation at rest of 90%. These authors suggest that patients who have good but not excessive forward pulmonary blood flow with good-sized pulmonary arteries and low pulmonary pressure are excellent candidates for bidirectional Glenn without completion of the Fontan operation unless they develop increasing cyanosis and/or fatigue with exertion. These patients obviously would be good candidates for completion of the Fontan, but it is hard to argue with their results of palliation with only the bidirectional Glenn when there is antegrade flow that results in good-sized pulmonary arteries.
Hsia et al. (10) present data on subdiaphragmatic venous flow dynamics in patients with Fontan circulation after diaphragm plication. Patients with biventricular circulation were compared with Fontan patients with normal diaphragms and Fontan patients who had required plication of the diaphragm after phrenic nerve damage. In Fontan patients with a plicated diaphragm, inspiration-derived hepatic venous flow was suppressed, and portal venous flow lost its normal expiratory augmentation. These flow dynamics are similar to those observed with failing Fontan circulations. Suboptimal splanchnic circulation might contribute to early problems of prolonged pleural effusions and ascities and potentially promote late Fontan failure. These authors document the problems with lung flow dynamics in Fontan patients who depend on excellent lung compliance for augmentation of flow into the lungs with inspiration. Although up to 20% to 30% of patients might show some return of diaphragm function after plication, these patients did not show such return and are at increased risk for complications when this unfortunate consequence occurs.
Ikai et al. (11) report on extracardiac conduit Fontan operation in 36 patients <10 kg and compared them with patients weighing more than 10 kg with similar hemodynamic status and operative procedures. Post-operative courses were identical in both groups except that smaller patients received slightly longer ventilator support, longer pleural drainage, and 8 days versus 7 days in intensive care. The debate has continued as to whether one should use the extracardiac Fontan in younger patients in whom it is expected that the conduit will have to be replaced as they outgrow it. The question about putting a larger conduit in the smaller patients has come up and whether significant dead space will be present in these patients and therefore predispose them to arrhythmia and thrombosis. These authors have not shown outgrowth of the conduit at this early follow-up, but whether they will be better off long-term than patients with a total cavopulmonary pulmonary connection is unclear.
Brown et al. (12) evaluated pre-operative MRI versus routine cardiac catheterization before bidirectional Glenn in infants with functional single ventricles with 41 patients on each arm of this randomized study. There were 4 treatment crossovers: 3 to catheterization and 1 to MRI. Patients who were known to need catheter intervention before the procedure were not included, and all patients had anesthesia for the MRI study. Catheterization resulted in more minor adverse events, longer pre-operative hospital stays (median, 2 days vs. 1 day) and higher hospital charges ($34,000 vs. $15,000). One major adverse event in the MRI suite was a thrombosis that resulted in transfer immediately to the catheter group, and the patient was able to be resuscitated and treated effectively. At 3 months' follow-up there were no differences in the clinical status, oxygen saturation, or frequency of reinterventions. Thus, in selected patients MRI is a safe, effective, and less costly alternative to routine catheterization in the evaluation of young patients in whom catheter intervention is not needed before bidirectional Glenn.
Ryerson et al. (13) report on the usefulness of heparin in patients with single ventricle palliation and PLE. The use of subcutaneous heparin was first reported by this group as a possible means of stabilizing and improving patients with PLE. Heparin might stabilize the cell-matrix interactions at the capillary endothelium or at the intestinal mucosa to decrease leakage of protein into the extravascular spaces. These authors report 17 patients whose PLE appeared at an average of 43 months after surgery; subjective symptomatic improvement occurred in 76%, and 3 patients (18%) went into clinical remission. Compared with the period before heparin, there was no difference in the number of hospital admissions or albumin infusions during the first year of therapy. Of the 3 patients, 2 with remission remained in long-term remission without further therapy and have been removed from heparin therapy. Obviously, some patients respond to this therapy and receive excellent long-term palliation. It does not work for everyone, and PLE remains difficult to treat effectively.
Friedrich-Rust et al. (14) report on noninvasive assessment of liver fibrosis in 39 patients with Fontan circulation. These authors used transient elastography, which is a system using a vibrating ultrasonic transducer, and detailed laboratory testing. Signs of liver fibrosis were found in 36 of 39 children according to the elastography method and in 28 of 39 children according to biochemical fibrosis markers. Fontan patients are at increased risk of developing liver fibrosis and cirrhosis, a finding that seems identical to findings in patients with right heart failure of prolonged duration. The risk increases with the age of the patient and the time interval since the Fontan procedure. These patients need careful attention to liver size, blood chemistry markers, and possibly this ultrasound method, which might detect problems at an early stage. Patients at higher risk include those with more elevated venous pressure and an enlarged liver.
Giardini et al. (15) report on the natural history of exercise capacity after the Fontan operation in 53 patients with 3 tests for each patient, with an average age of 14 years at the first test and an average of 7.7 years between tests. Age at operation was a mean of 6 years in 22 patients with total cavopulmonary connection and 7 years in 31 patients with atriopulmonary or atrioventricular connection. Exercise capacity was expressed as peak oxygen uptake that decreased at a rate of –2.6 ± 2.7% per year. The RV morphology and nontotal cavopulmonary connection Fontan were the only predictors of a more rapid rate of decrease in exercise performance. This decline in exercise capacity in Fontan patients, particularly those with systemic RVs, is worrisome. Hopefully, with improved flow dynamic status and earlier operation, this can be lessened with time.
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Hypoplastic Left Heart Syndrome (HLHS)
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Approaches to risk stratification in infants with hypoplastic left heart and outcomes continue to be of importance.
Glatz et al. (16) report a retrospective review of patients with HLHS and pre-natal restrictive atrial septal defect (ASD). Sixteen of 38 patients had the most severe form of obstruction with only 38% survival. Pre-natal diagnosis did not improve survival. Eight patients had progression of ASD obstruction from the first fetal to the first post-natal study; 7 patients underwent planned cesarean section followed by immediate surgical or catheter-based intervention with only 2 survivors (28%). These data document the critical nature of this subset of patients with HLHS. These authors also document the progression from a wide-open ASD at 34 weeks to virtually complete obstruction at term. Thus, these patients need careful follow-up, and fetal intervention needs to be further investigated; this might become the best therapy for this highly lethal condition in its most severe form.
Ashcraft et al. (17) report on aortic arch recoarctation after the Norwood procedure with a 30% incidence in 117 patients. The majority of arch interventions, whether surgical or catheter-based, occurred in the first 6 months after initial surgery. Use of bovine pericardium showed the greatest risk for recoarctation. Recoarctation after the Norwood procedure seems to still be with us, despite attempts to resect all ductal- and coarctation-producing tissue adequately and have the patch pass through the proximal and distal areas of narrowing. The increased after-load that recoarctation presents to a compromised RV remains a hazard for long-term outcome. Hopefully, further modification of this surgical procedure will improve this aspect of therapy.
Hickey et al. (18) report on 362 neonates with critical LV outflow tract obstruction enrolled by 26 institutions in the Congenital Heart Surgeons' Society database. Initial procedure indicated intended univentricular repair (n = 223; 84 deaths) or biventricular repair (n = 139; 39 deaths). Incremental risk factors for death after univentricular repair were tricuspid regurgitation, smaller mitral annulus Z scores, smaller indexed dominant ventricular length, and presence of a large ASD; risk factors after biventricular repair were minimal LV outflow tract diameter, endocardial fibroelastosis, LV dysfunction, and smaller mid-aortic arch. Univentricular survival advantage values, especially in borderline candidates, were more frequent and more consequential. Use of the univentricular survival advantage tool developed in this study might help identify infants in whom univentricular repair might be a better choice than attempted biventricular repair. It is always tempting to proceed with biventricular repair when it seems potentially feasible in terms of, hopefully, a better long-term outcome. These authors help identify patients in whom this could be a poor strategy. The more liberal use of a Ross-Konno procedure with or without arch repair as well as resection of endocardial fibroelastosis might improve survival for biventricular repair patients and, hopefully, can be sorted out with a multi-institutional study for those who have the ability to deal with these complex surgical options.
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Transposition of the Great Arteries
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Follow-up and natural history of patients undergoing arterial switch procedure are of considerable importance, as detailed in the following articles.
Bové et al. (19) studied 93 children after an arterial switch operation using echocardiography for functional and morphological assessment of both reconstructed arteries. With a mean follow-up of 5 years, aortic regurgitation (AR) of 2 or greater developed in 10% with intact ventricular septum versus 23% with VSD. A VSD and major pulmonary to aortic annulus size discrepancy were main precursors of early neoaortic valve dysfunction, whereas development of AR of 2 or greater was additionally related to duration of follow-up. After arterial switch operation, the neoaortic root is usually enlarged but with a growth pattern comparable to that of a normal population. The association of a VSD and major aortic root size discrepancy predisposes to both neoaortic valve dysfunction and root enlargement. Neopulmonary stenosis is a frequent finding but rarely has clinical consequences. These data indicate the need for continued diligence in follow-up of arterial switch patients, with particular attention to aortic root size and aortic valve dysfunction.
Agnoletti et al. (20) studied dilation and AR late after the arterial switch operation in 46 patients (ages 5 to 6 years) and in 20 matched healthy control subjects. There was acute angulation of the aortic arch, and the ratio of the ascending aorta to descending aorta diameters was significantly greater in patients who underwent the arterial switch operation compared with control subjects. The aortic arch angle was associated with a higher degree of AR. This gothic type of angulation of the aortic arch after arterial switch operation is a natural consequence of the French connection (posterior translocation of the ascending aorta) and is associated with aortic dilation and AR. Hopefully, this will not result in a multitude of patients with severe AR or who are predisposed to such in the future. Perhaps our surgical colleagues will figure out a way to do this operation with minimal acute aortic angulation.
Gottlieb et al. (21) reviewed the overall mortality and reoperation rate for 65 of 74 survivors with arterial switch operation for dextro transposition of the great arteries, VSD, and aortic arch obstruction. Distal transverse aortic arch z-score  –2.5, tricuspid valve (TV) z-score <0, repaired muscular VSD, and circulatory arrest time were predictors of mortality. Small transverse arch and small TV were risk factors for mortality in univariate analysis and remained significant in the subset of patients with short circulatory arrest times, suggesting that, even when controlling for technical factors, anatomic risk factors predict mortality. This is a high-risk group that includes patients who might be marginal candidates for 2-ventricle repair and might therefore need consideration for other types of palliative or reparative operation.
Quinn et al. (22) report a retrospective study of all patients undergoing the double-switch procedure for congenitally corrected transposition of the great arteries. Patients were divided into 2 groups: those not requiring morphological LV training (n = 33) and those completing morphologic LV training by pulmonary artery banding (PAB) (n = 11). The early results of these 2 groups were not different, but there was an increased risk of deterioration of morphological LV function over time in patients with LV training. This is a worrisome result in this group of patients who have undergone this complex procedure with good overall outcomes. The overall mortality was 12% for those not requiring training and 9% of those requiring morphologic LV training. This is obviously not different, however; there was a 46% development of moderate to severe LV dysfunction in patients requiring retraining versus 21% for those not requiring training. This group deserves careful study and follow-up to try to determine the risk factors resulting in severe dysfunction of the LV in these patients and attempts to prevent it in the future.
Ou et al. (23) report on computed tomography (CT) (angiography) in 133 consecutive children after arterial switch operation. The CT was fully evaluable in 126 of 130 patients and detected all 12 patients (9.2%) in whom invasive coronary angiography had identified coronary lesions (see Figs. 1, 3, and 5 in Ou et al. [23]). These children require anesthesia and are given propranolol to slow their heart rate to give optimal visualization of coronary anatomy.
This article and the succeeding editorial indicate the excellent quality data that can be obtained. There is a cost in terms of radiation that was slightly higher than with angiography. The question of predisposition of a child to malignancy later in life as a consequence of radiation exposure is suggested by 1 follow-up of children undergoing cardiac catheterization indicating a doubling of suspected cardiac malignancies over a mean follow-up of 29 years (24) Although MRI can result in similar images in many patients without any radiation risk, it is pointed out that relatively low spatial resolution, long scan time, and potential need for anesthesia are drawbacks when compared with CT imaging. Hopefully, these issues can be addressed in the future for MRI studies and/or CT can be done with lower radiation. The need for assessing coronary anatomy so exquisitely in arterial switch patients could be argued, but these patients need to enter adult life with a roadmap of their coronary anatomy to simplify later evaluation for acquired heart disease and to be certain significant lesions are dealt with in a timely and optimal fashion.
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Cardiac Surgery
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This section details several important studies related to general cardiac surgery and outcomes, including some with large databases.
Curzon et al. (25) report on cardiac surgery mortality in 3,022 infants ages 0 to 90 days weighing 1 to 2.5 kg and 2,505 patients >2.5 to 4 kg who underwent surgery from 2002 through 2004 at 32 participating centers within the Society of Thoracic Surgeons Congenital Heart Surgery Database. The smaller infants had an increased mortality for total anomalous pulmonary venous connection, coarctation, arterial switch, systemic to pulmonary artery shunt for pulmonary atresia with VSD, and the Norwood procedure. It is always difficult to decide whether to proceed with surgery in the small infant or hope for more growth and more maturity. Usually with symptomatology present in complex lesions, these patients do not grow well and might become worse candidates with time. Deciding the optimal time to operate is difficult. These data will give cardiologists and surgeons a reasonable picture to present to parents before deciding on the timing of surgery.
Li et al. (26) report on a prospective, randomized, placebo-controlled trial evaluating the pharmacodynamics of clopidogrel in children ages 0 to 24 months with a cardiac condition at risk for thrombosis. Patients were randomized to clopidogrel versus placebo in a 3:1 ratio in sequential groups. Of the 116 patients who were enrolled, 92 were randomized and 73 completed the study. A total of 79% of the randomized and treated patients were taking aspirin as well as clopidogrel. Compared with the placebo, clopidogrel resulted in 49% inhibition of the maximum extent of platelet aggregation. There was marked interpatient variability in the degree of platelet aggregation inhibition within each treatment-dose group and age group. No serious bleeding events occurred. This study shows that clopidogrel is well-tolerated in infants and young children at this dose and might be useful to decrease morbidity and mortality in those patients at risk for thrombotic disease.
Nieminen et al. (27) examined causes and modes of late death after pediatric cardiac surgery in 6,024 patients who survived their first operation during the years 1953 to 1989. A total of 9% or 592 died during the 45-year follow-up. Survival improved in patients operated in succeeding decades. The cause of death was confirmed by post-mortem evaluation in 81%. The majority died because of their CHD, and the main cause for CHD-related deaths was congestive heart failure (CHF) in 40%. Other causes included perioperative (26%), sudden (22%), and cardiovascular (12%) deaths. Accidental deaths and suicides were similar to the general population. There were 13 coarctation patients who died suddenly, and 5 had untreated aortic stenosis. In 4 patients, the underlying cause was a ruptured or dissected aorta. The overall incidence of lethal endocarditis was 0.07% (4 of 6,024). Two of these patients had a bicuspid aortic valve, 1 had a recoarctation, and 1 had univentricular CHF after Fontan operation. The number of patients lost to follow-up was only 4% of 6,024 who survived their first operation, and the cause of death was confirmed in 98%. This gives further impetus to the need for long-term careful follow-up of adults with CHD.
Geva et al. (28) report on the risk factors for reoperation for discrete subaortic stenosis in 111 subjects. Sixteen patients reported reoperation, and median follow-up was 8 years. Independent predictors of reoperation available before first surgery were <6 mm between the aortic valve and the obstruction and peak gradient by Doppler >60 mm Hg. If intraoperative variables were also considered, involvement of the mitral or aortic valve leaflets requiring surgical peeling also predicted recurrent stenosis. One of the more difficult issues for a cardiologist and surgeon is the recurrence of discrete subaortic stenosis in patients who seem to have an excellent result at early follow-up. These findings hopefully will result in fewer patients coming to reoperation as well as improved pre-operative counseling about recurrence risk.
Brown et al. (29) report on outcomes of 604 operations for 539 patients with Ebstein's anomaly. The mean age at the time of operation was 24 years with a range of 8 days to 79 years. One hundred eighty-two patients had TV repair, and 337 had tricuspid valve replacement (TVR). The 30-day mortality was 5.9% for the entire cohort (2.7% after 2001). Late survival was 85% at 10 years and 71% at 20 years. A multivariate analysis of overall mortality for the patient's first operation showed that increased hematocrit, pulmonary valve stenosis, TVR, absence of ablation of an accessory pathway, miscellaneous arrhythmia procedure, branch pulmonary enlargement, need for mechanical support post-operatively, emergency chest opening in the intensive care unit, and absence of sinus rhythm at dismissal were all predictive of mortality. When only pre-operative characteristics were included, increased hematocrit values, mitral valve regurgitation requiring surgical intervention, prior cardiac procedure, and moderate-to-severe to severe reduction in RV systolic function were associated with mortality. Eighty three percent of patients rated their health as excellent or good. There is a vast amount of data in this large series of patients with Ebstein's anomaly. These authors prefer TVR in patients in whom the possibility of a good-to-excellent repair of the TV is unlikely, and a bioprosthesis is the usual choice because of excellent durability in adults plus the ability to treat atrial arrhythmias with a concomitant maze procedure. Timing of the operation is very important. These authors use abnormal exercise tolerance, cyanosis, the presence or progression of arrhythmias, and progressive increase in RV size as indicators for operation. If echocardiography suggests a high probability of TV repair, earlier operation is advised. The RV function is felt to always be abnormal in Ebstein's anomaly, but quantification of RV function is challenging. Cardiac MRI can be useful for this purpose. This remains a difficult lesion to decide on operation timing in patients with minimal symptoms, minimal/moderate RV dilation, and mildly abnormal function. Earlier rather than later surgery is desirable before poor RV function becomes easily detectable.
Corno et al. (30) report on comparison of conventional PAB with the use of an implantable telemetrically controlled FloWatch (Endoart, Lausanne, Switzerland) device. There were 20 patients in each group with similar age and weight before PAB. Indications were preparation for biventricular repair in 16 of 20, univentricular repair in 2 of 20, and LV training of in 2 of 20 with conventional PAB versus 13 of 20, 5 of 20, and 2 of 20 infants, respectively, with the FloWatch PAB. There were 3 early and 2 late deaths after conventional PAB group and 2 late deaths with the FloWatch group. Post-operative mechanical ventilation and intensive care unit and hospital stays were significantly longer after conventional PAB. Reoperation to adjust the PAB was required in 7 of 20 infants after conventional PAB, whereas no reoperations were required after FloWatch PAB. Average cost in the intensive care unit and hospital was significantly less with the FloWatch group and resulted in overall lower cost, despite the $10,000 cost of the device.
This device has been proven useful by this group, and hopefully it can be more widely applied. You can not only increase the degree of banding but also decrease it with the FloWatch device. In addition, there is no distortion of the pulmonary artery and no need for pulmonary arterioplasty after removal.
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Interventional Catheterization
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Cardiac interventions continue to generate important observations.
Silversides et al. (31) studied the predictors of atrial arrhythmias after device closure of secundum ASD in 200 adults. Twenty percent of patients had a history of atrial tachycardia (AT). Early follow-up was available for 90% of the patients. The prevalence of AT was 17%. Of 171 patients with later follow-up (mean time 1.9 years), data were available for 90%, and AT was detected in 16%. Closure resulted in alleviation of symptoms, but symptoms alone did not identify patients at risk of recurrent AT. After ASD closure, the likelihood of remaining arrhythmia-free was highest in patients without a history of AT and those age <40 years at closure.
This provides good data for counseling patients regarding percutaneous ASD closure. Unfortunately, the data indicate that arrhythmias might still be an issue after closure with a similar prevalence as has been reported after surgical closure. The message is clear: early closure of ASDs that are large enough to cause right heart enlargement is highly desirable.
Butera et al. (32) report on safety and efficacy of transcatheter closure of perimembranous VSD in 104 patients with a mean age of 14 years (range 0.6 to 63 years). The device was implanted successfully in 96% and median device size was 8 mm. No deaths occurred. Total occlusion rate was 47% at completion, 84% at discharge, and 99% during follow-up. A total of 13 early complications occurred, but in all but 2 subjects these were transient. The median follow-up was 38 months, and the most significant complication was atrioventricular block (AVB), which required pacemaker implantation in 6 subjects (5.7%; 2 in the early phase and 4 during the follow-up). All patients experiencing AVB were >6 years of age. These authors show good results for closure of perimembranous VSD. Unfortunately, AVB occurred in a greater percentage than found in surgical series. In addition, they closed 1 VSD as small as 3 mm in diameter. Such small defects should not be closed by interventional or surgical means, in my opinion. The long-term natural history of these defects is benign when compared with a 6% prevalence of AVB.
Sievert et al. (33) report on 30 patients who were enrolled for patent foramen ovale closure without an implant by the successful application of radiofrequency energy. Success was achieved in 27 patients. The remaining 3 patients received an implantable closure device. There were no serious procedure-related adverse events, including recurrent strokes, deaths, or perforations that occurred as a result of the procedure. The mean follow-up was 6 months, and 13 of the 30 patients experienced patent foramen ovale (PFO) closure after the first procedure. Nine of the patients whose PFO remained patent after the first procedure elected to receive a second radiofrequency procedure. The PFO was closed for 6 of those patients after the second procedure, which resulted in a secondary closure rate of 63%. This study demonstrates that transcatheter closure of an intracardiac defect without a permanent implant is technically feasible. Whether patients are at risk of thrombosis remains to be seen. It is an exciting potential application of small ASD closure without the use of an implant.
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Medical Therapy
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Shaddy et al. (34) report on the randomized trial of carvedilol in children with CHF. One hundred and sixty-one children and adolescents were enrolled with CHF due to dilated cardiomyopathy or CHD (inclusive of both systemic LVs and systemic RVs). Patients were randomized in a 1:1:1 ratio to twice-daily dosing with placebo, low-dose carvedilol, or high-dose carvedilol. Primary outcome was a composite measure of CHF outcomes, which was described as "worsened," "improved," or "unchanged." There was no statistically significant difference in the composite end point of the patients assigned to placebo and that of either dosage group. Carvedilol was not associated with changes in CHF at 8 months compared with placebo. Most therapies used in children have been evaluated only in trials of adults, and it is assumed that results will be applicable to children as well; this trial demonstrates that supposition is not always true. This was a difficult trial to pull off in terms of getting enough patients to perform randomization with different subgroups. The authors should be congratulated for their work. Hopefully, further data can be obtained with similar trials in terms of medical treatment of CHF in patients with CHD.
Doughan et al. (35) report a retrospective analysis of medical therapy for patients with systemic RV dysfunction with transposition of the great arteries. A significant improvement in New York Heart Association functional class was found after 4 months of therapy with beta-blocker drugs (carvedilol or metroprolol). Functional improvement was significant mostly in those patients with pacemakers who received higher maintenance doses of carvedilol. The RV end-diastolic area was significantly greater in untreated patients at the end of the follow-up period, whereas it was unchanged in treated patients. This retrospective study suggests that a larger controlled trial of the use of beta-blocker drugs in older patients with systemic RVs might be useful, despite the prior report in children (34).
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Genetics
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Bruneau (36) reviews recent studies that have uncovered the genetic basis for some of the common forms of CHD and provides insight into how the heart develops and how dysregulation of heart development can lead to abnormalities. This article indicates how far we've come and yet how much there is still to understand about what factors regulate the development of the heart as well as its function later in life. Hopefully, articles like these will stimulate young scientists to get involved in this blossoming field.
Hinton et al. (37) report on 38 probands with HLHS in which a 3-generation family history was obtained and a sequential sampling strategy with echocardiograms on family members was performed. A total of 235 participants were recruited. Hertability of HLHS and associated cardiovascular malformation (CVM) were estimated with maximum-likelihood–based variance decomposition. All HLHS probands had aortic valve hypoplasia and dysplasia; dysplasia of the mitral, tricuspid, and pulmonary valves were also noted. Overall, 21 of 38 (55%) families had more than 1 affected individual, and 36% of participants had CVMs, including 11% with bicuspid aortic valve. The heritability of HLHS alone and with associated CVM were 99% and 74%, respectively. The sibling recurrence risk for HLHS was 8% and for CVM was 22%. These data add further insight into the heritability of left-sided lesions and further impetus to research into the aortic causes of these defects.
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Pulmonary Atresia
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Gardiner et al. (38) report on morphological and functional predictors of eventual circulation in the fetus with pulmonary atresia (PAIVS) or critical pulmonary stenosis (CPS) with intact septum. These authors studied 21 fetuses with PAIVS (18 fetuses) or CPS (3 fetuses) between 1998 and 2004. The best predictive scores for specific gestations were pulmonary valve z-score, median TV z-score, and the combination of median pulmonary valve and the median TV/mitral valve ratio. The best predictive scores for postnatal outcomes in PAIVS/CPS are a combination of morphologic and physiological variables, which predict a biventricular circulation with a sensitivity of 92% and specificity of 100% before 26 weeks. These data should prove quite useful for patient selection for possible fetal intervention to preserve biventricular outcome.
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References
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J. Am. Coll. Cardiol. 2008 52: A31.
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Long-Term Management of...
Fontan Surgery