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J Thorac Cardiovasc Surg 2009;137:371-379
© 2009 The American Association for Thoracic Surgery
Congenital Heart Disease |
a Department of Cardiac Surgery, Children's Hospital of Boston, Harvard Medical School, Boston, Mass
b Department of Cardiology, Children's Hospital of Boston, Harvard Medical School, Boston, Mass
Received for publication May 16, 2008; revisions received October 1, 2008; accepted for publication October 26, 2008. * Address for reprints: Frank A. Pigula, MD, Children's Hospital of Boston, Department of Cardiothoracic Surgery, 300 Longwood Ave, Farley 144, Boston, MA 02115. (Email: Frank.pigula{at}tch.harvard.edu).
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Abstract |
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 Top Abstract IntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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Methods: Between January 1990 and July 2007, 371 patients received a diagnosis of heterotaxy syndrome; 91 (91/371, 24.5%) underwent biventricular repair. Left atrial isomerism was present in 73% (66/91) and right atrial isomerism in 10% (9/91), with indeterminate atrial anatomy in 17% (16/91). Median age at biventricular repair was 6.8 months (5 days to 22.3 years). Systemic venous anomalies were present in 75 patients, pulmonary venous anomalies in 26, and endocardial cushion defects in 36. Transposition complexes were present in 15 patients with atrioventricular discordance in 10; 8 underwent double switch, 2 received a physiologic repair, 2 underwent arterial switch, and 3 underwent the Rastelli operation. Other conotruncal anomalies included double-outlet right ventricle in 10 patients, tetralogy of Fallot in 3, and hemitruncus in 2. Separation of systemic from pulmonary venous return included intra-atrial baffling in 48 patients and extracardiac grafting in 2. Combined lesions were common, occurring in 99% (90/91). Statistical analysis with Kaplan–Meier and Cox proportional hazards models were performed.
Results: Average follow-up was 44.9 ± 57.5 months (3 days to 189.3 months). Kaplan–Meier estimated survival was 93.4% at 10 years; unbalanced complete atrioventricular canal was the only risk factor for mortality (P = .006). Subsequent procedures were common with a 10-year freedom from reoperation or reintervention of 38% ± 7.5%. Arrhythmias occurred in 36 (39.6%) patients; bradyarrhythmia in 27 (29.7%) and tachyarrhythmia in 15 (16.5%). Freedom from any arrhythmia was 53.9% ± 6.7% at 10 years.
Conclusions: Excellent survival for patients with heterotaxy undergoing biventricular repair can be expected, even for multiple, complex lesions. Reintervention is common, and arrhythmia is a long-term concern. This experience shows that patients with heterotaxy syndrome and complex cardiac anatomy can be considered for biventricular repair. Patients with unbalanced complete atrioventricular canal are a high-risk group for which selection criteria are particularly important.
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Introduction |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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Although single ventricle palliation is unavoidable for many patients, a subset of heterotaxy patients will have anatomy that may be suitable for biventricular repair.4-7 The present study seeks to determine the frequency of biventricular repair for heterotaxy syndrome at our institution and to analyze the anatomic factors that predict outcomes after biventricular repair. Specifically, we examined early and late survival, arrhythmia, functional status, residual lesions, and freedom from reintervention or reoperation.
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Patients and Methods |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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Definitions
We2 have defined heterotaxy syndrome as the presence of a pattern of typical cardiac, vascular, and visceral abnormalities that indicated abnormal sidedness. Heterotaxy syndrome is largely synonymous with the syndromes known as left or right atrial isomerism or asplenia or polysplenia syndrome. Clinically, we have chosen atrial morphology as the primary classification index. If the atrial morphology was ambiguous, these patients were classified as having "indeterminate" anatomy.
Although cardiac malformations associated with heterotaxy syndrome are prone to clustering, they show considerable overlap that often defies clear classification. For this reason, patients were considered to have indeterminate atrial anatomy if, by surgical inspection, atrial isomerism was not clearly identifiable and if other findings typical of polysplenia or asplenia were not identified during cardiac evaluations.
Tachyarrhythmia was defined as the presence of documented atrial fibrillation, atrial flutter, atrioventricular (AV) reciprocating tachycardia, ectopic atrial tachycardia, accelerated junctional rhythm, ventricular tachycardia, or ventricular fibrillation, but not sinus tachycardia. Bradyarrhythmia included sinus bradycardia, abrupt and pronounced sinus pause or arrest, sick sinus syndrome, slow junctional escape rhythm, junctional rhythm at physiologic rates without evidence of sinus node activity, and second- or third-degree AV block. All arrhythmias that were reported in the charts were noted, without attempt to determine clinical impact. This definition includes even brief periods of intraoperative or early postoperative arrhythmia that resolved spontaneously and did not recur.
Anatomy
On the basis of surgical and echocardiographic evaluations, 9 patients (9/91, 10%) had right atrial isomerism, 66 patients (66/91, 72.5%) had left atrial isomerism, and 16 patients (16/91, 17.6%) had ambiguous atrial anatomy and were classified as having "indeterminate" anatomy. These patients were distinguished by the wide variability in associated cardiac lesions; however, in general they could be assigned to abnormalities of the endocardial cushion, septal defects, and conotruncal abnormalities (Table 1
).
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Thirty-six (28%) patients had a common AV valve; moderate or greater AV valve regurgitation was demonstrated by echocardiography or catheterization in 28 % (10/36). Transposition complexes were present in 15 (16.5%) patients and normally related great vessels were present in 66 (72.5%) Ten (11%) patients were diagnosed with double-outlet right ventricle (DORV) with muscular outlet conus under each great vessel, which was usually associated with pulmonary stenosis (n = 7) or atresia (n = 2). Some of these patients were the subject of a previous report from our institution.8
Abnormalities of pulmonary venous connections were present in 26% (24/91) of patients, and systemic venous abnormalities were identified in 82% (75/91) of patients. Forty-nine (53.9%) patients had bilateral superior vena cava (SVC), usually without a connecting innominate vein, and 61 (67.0%) patients had an interrupted inferior vena cava (IVC) with azygos continuation. Combined lesions were very common, occurring in 99% (90/91) of patients.
Surgical Treatment
Twenty-three patients underwent 43 procedures before repair. Twenty of these procedures were related to optimizing pulmonary blood flow with a pulmonary artery band or shunt, whereas most of the remaining pre-repair procedures involved repair of anomalous pulmonary venous connections (Appendix E1).
The biventricular repair was accomplished anatomically with the left ventricle used as the systemic ventricle in 89 patients; a physiologic repair with the right ventricle used as the systemic ventricle was done in 2.
Among the 10 patients with L-transposition of the great arteries, anatomic repair included a double switch operation in 8 patients; Senning and Rastelli procedures in 4; Mustard and Rastelli procedures in 1; Mustard and arterial switch in 2; and intra-atrial baffling of a left SVC, repair of total anomalous pulmonary venous return, and Rastelli procedure in 1. The physiologic repair was achieved by ventricular septal defect (VSD) closure with insertion of a left ventricle–pulmonary artery conduit in 2 patients with L-transposition and pulmonary atresia.
Among the 5 patients with D-transposition of the great arteries, the arterial switch operation was performed in 2, and the Rastelli procedure was performed in 3. One patient with DORV and subpulmonic VSD also underwent an arterial switch operation.
Atrial septation, resulting in exclusive atrial drainage to a dedicated ventricle, was required in 50 patients. It required intra-atrial baffling in 41 patients (ie, unroofed coronary sinus, left SVC), atrial switch in 7, and extracardiac graft interposition in 2.
Statistical Analysis
Statistical analyses were performed with SPSS version 14.0 software (SPSS, Inc, Chicago, Ill). Data were presented as a mean ± standard deviation or a median with ranges as appropriate. Simple binomial proportions were compared by Fisher's exact test. Estimated survival and freedom from reintervention, reoperation, tachyarrhythmia, and bradyarrhythmia were determined by the Kaplan–Meier method. Variables were evaluated by the likelihood ratio test in the Cox proportional hazards regression model. Hazard ratios with 95% confidence intervals were constructed for the significant multivariable predictors. All of the analyzed data were selected on the basis of a review of medical records, operative notes, all available electrocardiograms, echocardiography reports, and cardiac catheterization reports. The follow-up status of patients was determined by retrospective review of hospital records.
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Results |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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There were 2 (2.2%) late deaths. One patient with left isomerism underwent total repair for DORV and CAVC at 8 months of age after pulmonary artery banding and permanent pacemaker implantation; this patient died of neurologic complication 101 days later after cardiac catheterization. One patient with left atrial isomerism underwent VSD closure at 4 months of age and died of end-stage liver disease and sepsis resulting from extrahepatic biliary atresia 167 days after the operation.
Kaplan–Meier estimated survival for the entire cohort was 93.4% ± 3.2% at 1, 5, 10, and 15 years (Figure 1 ). Multivariable analysis identified the presence of an unbalanced ventricle as an independent risk factor for death (hazard ratio = 29.616; P = .006) (Table 2 ). The designation of "unbalanced ventricle" was made by the attending cardiologist on the basis of the information accumulated from the imaging studies regarding left ventricular size, papillary muscle number and location, and the amount of AV valve tissue dedicated to each ventricle. Other variables examined, such as the presence of a preoperative shunt, pulmonary artery banding, type of isomerism, common AV valve, preoperative AV valve regurgitation of at least moderate degree, ventriculoarterial connection, total anomalous pulmonary venous return, pulmonary atresia/stenosis, and bilateral SVC and IVC interruption, were not statistically significant risk factors for death.
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Reoperations
Thirty-seven reoperations were required in 28 (30.8%) patients at an average of 29.4 ± 41.5 months (2 days to 151.1 months, Table 2) after repair (Appendix E2). More than half of the reoperations were for repair/replacement of the AV valves, revision of the RVOT, or for placement of a pacemaker.
Freedom from reoperation was 77.5% ± 5.1% at 1 year, 63.2% ± 6.7% at 5 years, 50.8% ± 7.8% at 10 years, and 35.6% ± 10.8% at 15 years.
Catheter Reintervention
Thirty reinterventions were required in 21 patients (21/91, 23.1%) an average of 29.0 ± 32.5 months (15 days to 114.5 months) after repair (Appendix E3). Catheter reintervention was most commonly performed for relief of RVOT stenosis and for a smaller number of residual septal defects and rhythm disturbances. Two patients had aortopulmonary collaterals, and both required postoperative catheter occlusion. Freedom from reintervention was 84.9% ± 4.7% at 1 year, 65.4% ± 7.1% at 5 years, 51.3% ± 8.5% at 10 years, and 51.3% ± 8.5% at 15 years.
Freedom from reintervention or reoperation was 71.4% ± 5.5% at 1 year, 47.6% ± 7.0% at 5 years, 38.0% ± 7.5% at 10 years, and 30.4% ± 9.1% at 15 years (Figure 1). Multivariable analysis using the Cox regression model indicated that pulmonary stenosis (P = .001), pulmonary atresia (P = .002), and the presence of a common AV valve (P = .008) were independent predictors for the need of reintervention and reoperation (Table 2).
Arrhythmia
Arrhythmias occurred in 36 (39.6%) patients. Bradyarrhythmia occurred in 27 (29.7%). A permanent pacemaker was implanted in 17 patients for one or more of the following indications: complete AV block in 10, sinus node dysfunction in 6, second-degree AV block in 2, third-degree AV block in 1, and sinus bradycardia in 1. The pacemaker was implanted preoperatively in 4 patients, intraoperatively in 7, and after repair in 6. Junctional rhythm with sinus node dysfunction was observed in 8 patients, and transient complete AV block occurred in 2. Tachyarrhythmia occurred in 15 (16.5%) patients. Ventricular tachycardia occurred in 5 patients, necessitating transvenous insertion of an automatic implantable cardioverter defibrillator (AICD) in 1 and radiofrequency ablation in 1. Accelerated junctional rhythm occurred in 5, ectopic atrial tachycardia in 4, and ventricular fibrillation in 1.
Freedom from tachyarrhythmia was 86.9% ± 3.8% at 1 year, 86.9% ± 3.8% at 5 years, 73.7% ± 7.8% at 10 years, and 63.1% ± 11.8% at 15 years. Freedom from bradyarrhythmia was 71.5% ± 5.1% at 1 year, 65.3% ± 6.3% at 5 years, 65.3% ± 6.3% at 10 years, and 60.2% ± 7.5% at 15 years. Freedom from overall arrhythmia was 62.7% ± 5.5% at 1 year, 56.9% ± 6.4% at 5 years, 53.9% ± 6.7% at 10 years, and 41.2% ± 9.8% at 15 years (Figure 2 ). Multivariable analysis using the Cox regression model indicated that pulmonary stenosis (P = .038) was an independent predictor for bradyarrhythmia and that older age at biventricular repair (P = .005) predicted tachyarrhythmia (Table 2).
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Discussion |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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Previous data from our institution reported that Kaplan–Meier estimated survival for patients undergoing the Fontan operation was 90% at 1 year and 87% at 10 years and is comparable with what we2 report for biventricular repairs (93%). Although only 70% of Fontan patients with heterotaxy were considered to be in NYHA functional class I, 98% of assessed patients with biventricular repairs were in NYHA class I.
In contrast to the single ventricle experience, AV valve regurgitation and anomalous pulmonary venous connections were not found to be important contributors to mortality after biventricular repair. The only risk factor identified for mortality was the presence of unbalanced CAVC. Among 10 patients with unbalanced CAVC, there were 2 deaths (1 from sepsis, 1 from neurologic injury), despite evidence of an adequate cardiac repair. The nonsurvivors tended to be younger (2.1 ± 2.7 months) than survivors (9 ± 14.3 months) and required more procedures for repair (ie, CAVC, coarctation, left SVC baffle, 3.5 ± 0.7) than did survivors (3.0 ± 0.9), although neither difference was significant (P > .5).
Although these 10 patients were considered to have "mildly" unbalanced ventricles, this is admittedly a qualitative designation, and no accepted criteria for the suitability of biventricular repair in the setting of "unbalanced" CAVC are easily applicable to the individual patient. For this reason, the decision to proceed with biventricular repair in these patients was determined on a case-by-case basis by the attending cardiologists and surgeon.
Although overall mortality was low, morbidity persists. The incidence of postoperative arrhythmia was significant compared with reports of heterotaxy patients undergoing single ventricle palliation.2,9-11 Tachyarrhythmia was associated with older age at operation, whereas the need for RVOT procedures to relieve stenosis was related to the development of bradyarrhythmias. Neither bradyarrhythmias nor tachyarrhythmias were related to the type of isomerism (P = .886, P = .112, Cox proportional hazards model). The types of atrial baffling, AV valve regurgitation, and systemic and pulmonary venous anomaly were not related to the occurrence of arrhythmia. Implantation of a permanent pacemaker was more common with left atrial isomerism (13/66, 19.7%) than right atrial isomerism (1/9, 11.1%), but this difference was not statistically significant (P = .538, 
2).
The need for reintervention and/or reoperation was also quite common among this patient population. Pulmonary stenosis (P = .001), pulmonary atresia (P = .002), and the presence of a common AV valve (P = .008) were statistically significant risk factors for the need for reintervention and reoperation. Among the 20 patients with pulmonary stenosis, only 3 received transannular patches. Of these 3, 2 required subsequent reoperation for the insertion of a pulmonary valve or valved conduit, and the third required catheter dilatation of the right pulmonary artery. Thus, the expected advantage of transannular patching, that is, avoidance of subsequent RVOT procedures, was not realized. Eight (40.0%) patients underwent the reinterventions or reoperations for right ventricle–pulmonary artery conduit after biventricular repair.
Among the 36 patients with common AV valve, 14 (38.9%) patients underwent subsequent procedures for the AV valve (such as mitral valvuloplasty in 8, tricuspid valvuloplasty in 3, and mitral valve replacement in 1) or permanent pacemaker insertion (n = 3) after biventricular repair. Our analysis identified the presence of a common AV valve as a significant risk factor for reoperation and substantiates the clinical impression that common AV valve anatomy in heterotaxy syndrome can be particularly problematic. Most of these valves are reparable but remain at risk for future intervention.12 Although the incidence of reintervention/reoperation was significant, it has not been associated with additional mortality (arrhythmia vs mortality. P = .268; reintervention and reoperation vs mortality, P = .292, Cox proportional hazards model).
The classification of heterotaxy patients on the basis of anatomic criteria is imprecise, even when the diagnosis is based on postmortem examinations. Using venous anatomic criteria for the diagnosis of heterotaxy syndrome, Van Praagh and Van Praagh13 were able to diagnose 100% of polysplenia cases but only 36% of cases with asplenia. When atrial appendage criteria were taken into consideration, only 81% of cases of asplenia fit into the expected anatomic pattern.
That being said, in our series, only 9 patients with a diagnosis of right atrial isomerism underwent biventricular repair; transposition complexes were present in 6 patients (AV discordance in 5), CAVC in 4, DORV in 1, and pulmonary artery and pulmonary vein anomalies were common. All 9 survived biventricular repair. Although reports of biventricular repair in the setting of right atrial isomerism are rare and sporadic,14,15 most have reported relatively high mortality.7 The unsuitability of most patients with right atrial isomerism for biventricular repair is reflected by reports showing right atrial isomerism to be the predominant diagnosis in heterotaxy patients undergoing the Fontan operation. In our experience, biventricular repair for right atrial isomerism is uncommon but can be considered for carefully selected patients.
When considering a surgical strategy for heterotaxy patients, we16-18 have pursued biventricular repair in the presence of two ventricles of adequate volume and function, and septatable AV valves and venoatrial connections. Although the presence of adequate anatomic components identified above is a prerequisite for successful biventricular repair, they do not demand it. Despite the presence of favorable anatomic components, some patients with complex combined lesions may not be amenable to a biventricular repair.18,19 It is important to recognize that patient selection is an important determinant of success. Given the extent of the anatomic variability of these patients, there are no clear criteria to determine suitability for biventricular repair for these patients, and each has to be considered on an individual basis. However, our findings that AV valve regurgitation and anomalous pulmonary venous connections do not place a patient at risk for mortality after biventricular repair (as opposed to the Fontan operation) should be taken into consideration when considering the surgical options for borderline cases.
In summary, biventricular repair for selected patients with heterotaxy who have favorable anatomy results in excellent survival and NYHA functional status. Long-term morbidities, including arrhythmia and reoperation/reintervention, remain common.
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Appendix E1 |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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BT, Blalock–Taussig; PA, pulmonary artery; PPM, permanent pacemaker; PDA, patent ductus arteriosus; CoA, coarctation of aorta; TAPVR, total anomalous pulmonary venous return; VSD, ventricular septal defect; RV, right ventricle; CS, coronary sinus; PV, pulmonary vein.
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Appendix E2 |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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MVP, Mitral valvuloplasty, PVR, pulmonary valve replacement; MVR, mitral valve replacement; MVP, mitral valvuloplasty; AVP, aortic valvuloplasty; TVP, tricuspid valvuloplasty; ASD, atrial septal defect; BCPS, bidirectional cavopulmonary shunt; RVOT, right ventricular outflow tract; PA, pulmonary artery; PPM, permanent pacemaker; PAPVR, partial anomalous pulmonary venous return; RPA, right pulmonary artery; RV-PA, right ventricle–pulmonary artery; PS, pulmonic stenosis; LSVC, left superior vena cava; RA, right atrium; PV, pulmonary vein; VSD, ventricular septal defect; SubAS, subaortic stenosis; RUL, right upper lobe.
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Appendix E3 |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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RV, Right ventricle; PA, pulmonary artery; LV, left ventricle; RVOT, right ventricular outflow tract; VSD, ventricular septal defect; ASD, atrial septal defect; AICD, automatic implantable cardioverter defibrillator; PPM, permanent pacemaker; VT, ventricular tachycardia; MS, mitral stenosis; TV, tricuspid valve; TS, tricuspid stenosis; ASD, atrial septal defect; APCs, aortopulmonary collaterals; RUL, right upper lobe.
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Footnotes |
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References |
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TopAbstractIntroductionPatients and MethodsResultsDiscussionAppendix E1Appendix E2Appendix E3References |
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