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Ann Thorac Surg 1999;68:2158-2163
© 1999 The Society of Thoracic Surgeons
a Departments of Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
b Surgery, Toronto Congenital Cardiac Centre for Adults, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
Address reprint requests to Dr Harris, Toronto General Hospital, Gerrard Wing, 3-562, 150 Gerrard St W, Toronto, ON M5G 2C4, Canada;
e-mail: lharris{at}torhosp.toronto.on.ca
| Abstract |
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Methods. We retrospectively examined the outcome and frequency of atrial arrhythmias in 85 adult patients (46% men) with congenital heart defects who underwent tricuspid valve operation between 1961 and 1995.
Results. The majority had either Ebsteins anomaly (22%), congenitally corrected transposition (19%), tetralogy of Fallot (15%), atrial (13%), or ventricular (11%) septal defects. Forty-two (49%) patients had sustained arrhythmias within 1 year before operation. After tricuspid valve operation, 21 patients (50%) had recurrence of atrial arrhythmias, and 7 in preoperative sinus rhythm developed late rhythm disturbances. Multivariate analysis identified age at operation and preoperative arrhythmias as independent predictors of late arrhythmias. Perioperative mortality was 5%, and there were seven late deaths. Survival was 91% at 5 years, and 83% at 10 years.
Conclusions. Surgical intervention does not prevent recurrence of atrial arrhythmias. Tricuspid valve operation in patients with congenital heart disease can be performed with a low risk of perioperative mortality and good long-term outcome.
| Introduction |
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Limited data exist regarding the prevalence of atrial arrhythmias before and after TV operation in this patient population. The prevalence of arrhythmias does not diminish after operation for Ebsteins anomaly [6], unless surgical resection of accessory bypass tracts is undertaken [7, 8]. An examination of rhythm disturbances in patients with congenital heart disease is important, as this may have implications for long-term outcome.
We reviewed the perioperative and long-term outcome of 85 adult patients with congenital heart defects who underwent TV repair or replacement during the past three decades. We also examined the frequency of atrial arrhythmias before and after operation in these patients.
| Patients and methods |
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Patient data
Data were gathered on the complete surgical history of each patient. For the index operation, specific data on valve repair and replacement was identified. Preoperative and late follow-up clinical data included symptoms before operation, a history of arrhythmias, New York Heart Association (NYHA) functional class, and clinical evidence for ventricular failure. Information on the prevalence of atrial arrhythmias was gained from electrocardiographic data, Holter monitor information, and written documentation. Patients were defined as having an atrial arrhythmia if they had experienced a documented, sustained episode of atrial fibrillation, flutter, or supraventricular tachycardia associated with symptoms. Episodes of asymptomatic, nonsustained atrial arrhythmia observed only during Holter monitoring were not included. Outcome events were defined as death and late arrhythmia (ie, beyond the 30-day perioperative period).
Data analysis
Data analyses were performed using SPSS for Windows (version 8.0; SPSS Inc, Chicago, IL). Data were presented as mean plus or minus one standard deviation. Patient survival was displayed using the Kaplan-Meier method. Separate analyses were performed to determine the predictors for death and late arrhythmia. The predictive role of the following variables were analyzed: gender, previous operation, preoperative NYHA class, concomitant operation on other valves, nature of procedure (replacement versus repair), nature of artificial valve (bioprosthesis versus mechanical valve), nature of valve position (systemic versus venous ventricle), age at operation, and arrhythmias before TV operation. Univariate analysis of candidate predictors was performed using a Cox proportional hazard model. Collinearity between variables was examined; highly correlated variables (correlation coefficient, > 0.70) were combined into a composite variable. Predictors with a significance level of less than 0.20 on univariate analysis were entered into a multivariate Cox proportional hazard model using a stepwise backward elimination algorithm. The significance level for the multivariate model was set at 0.05 (two-sided).
| Results |
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Thirty-nine patients (46%) complained of palpitations, and 13 patients (15%) had experienced syncope. Forty-two patients (49%) had symptomatic atrial arrhythmias within 1 year before TV operation. Of these, 30 (71%) had atrial fibrillation or flutter, 7 (17%) had arrhythmias associated with Wolff-Parkinson White syndrome, and 5 (12%) had sustained supraventricular tachycardia. None of the patients in this study had clinically important ventricular arrhythmias.
Surgical data
The majority of patients (62%) had undergone cardiac operation before the index TV procedure. Twenty-nine patients (34%) had 1 previous operation, 15 (18%) had 2, 8 (9%) had 3, and 1 patient (1%) had 4 prior cardiac operations. The most common previous surgical procedures were ventricular septal defect repairs, atrial septal defect repairs, and Blalock-Taussig shunts.
Forty-six patients underwent TV repair, and 39 patients underwent TV replacement (Table 2). Thirty-three patients of the TV repair cohort had annuloplasty rings placed; the remaining 13 patients underwent TV leaflet repair, which included plication of the valve commissure and approximation of the valve leaflets. When TV replacement was undertaken, valve leaflets and chordal attachments were preserved wherever feasible. The septal leaflet was used to attach the prosthesis if possible. On occasion, a supracoronary sinus position was used to avoid conduction tissue. Valve leaflets were excised or chordal attachments resected when substantial leaflet deformity or the potential for obstruction existed.
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Six patients underwent intraoperative electrophysiologic mapping studies (4 patients with Wolff-Parkinson White, 1 patient with atrial flutter, and 1 patient with sustained atrial tachycardia). Of the 4 patients with Wolff-Parkinson White, 2 underwent intraoperative surgical resection, and 2 cryoablation of the accessory pathway.
After the index operation, 13 patients underwent 1 subsequent operation, and 3 patients underwent 2 subsequent cardiac operations. Three had a second TV operation (1 mechanical rereplacement and 2 repairs), and 1 patient underwent 2 bioprosthetic rereplacements after original bioprosthetic valve replacement at age 4 years.
Outcome
Three of 62 patients operated on as adults (5%) died perioperatively. One patient died intraoperatively due to massive left pulmonary embolism. This 19-year-old patient with a univentricular heart was in NYHA class II preoperatively, and had 3 previous cardiac operations before the attempted TV replacement with a bioprosthetic valve. Of the 2 early postoperative deaths, 1 patient with Ebsteins anomaly died of perioperative coagulopathy, and 1 patient with a ventricular septal defect died from low output syndrome due to left ventricular failure. Both of these patients underwent TV repair operations. They were in NYHA classes III and IV preoperatively, and neither had undergone previous cardiac operation.
Postoperative NYHA data are displayed in comparison to preoperative status in Figure 1. Fifty-six percent of patients were in NYHA class III or IV within 1 year before operation. The NYHA data were available for 66 of the 75 surviving patients (88% complete follow-up). At most recent follow-up, 82% of these patients were in NYHA class I, with no symptomatic limitations.
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Median duration of follow-up was 5.2 years (2 months to 30 years). Seven patients (8%) died late after TV operation. Late deaths occurred between 2.5 months and 13.5 years after operation (mean, 6.4 ± 4.5 years). The survival of patients after TV operation, including postoperative deaths is portrayed in Figure 3. To date, survival after operation is 91% at 5 years and 83% at 10 years.
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| Comment |
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There are several possible explanations for the lower mortality in our population. The majority of patients were older at the time of operation than in previous studies. The median age for the index operation was 29 years. Sixty-two patients (77%) were aged 18 years or older at the time of the TV operation, and 78 patients (92%) were aged 10 years or older. A previous report found that TV operation is relatively safe when performed in older children, but has an extremely high mortality rate in infants [1]. In addition, previous studies reporting a high mortality [2, 3] comprised a greater proportion of patients with multivalvular disease. The majority of our patients (78%) underwent TV repair or replacement alone. Only 19 patients (22%) had concomitant operation performed on other valves at the time of the index operation, although 57 patients (67%) underwent other lesion repairs (eg, atrial septal defect repair). Our study population was also limited exclusively to patients with congenital heart disease. This may have impacted on the mortality rate when compared with previous studies comprised predominantly of patients with acquired cardiac lesions [2, 3, 5]. The latter often include patients with multiple valvular disease and secondary tricuspid incompetence.
Consistent with other studies [79], the majority of patients who died late postoperatively had previously undergone TV replacement (6 of 7 patients). Of these, 3 had mechanical and 3 bioprosthetic prostheses. In a recent surgical review of a large Ebstein cohort [10], the investigators observed that although valve repair was the primary objective whenever a good to excellent result could be obtained, valve replacement (bioprosthetic or mechanical) provided comparable long-term results at 10 years of follow-up (82% versus 83% freedom from reoperation, respectively), particularly in older patients. Data on long-term results of mechanical versus bioprosthetic TV replacement is conflicting. Some reports have observed improved results with bioprosthetic valve replacement in the tricuspid position [11], whereas other studies favor mechanical prostheses, citing significant early valvular calcification in the right heart despite diminished relative hemodynamic stress [1]. In young patients, it is our policy to use mechanical valves in the systemic circulation when the valve is failing and a bioprosthesis for patients requiring atrioventricular valve replacement in the pulmonary circulation. Valve repair was undertaken for only 1 patient with congenitally corrected transposition, as repair in these patients is often not durable. Our low overall mortality made it difficult to assess the prognostic value of the type of prostheses on late survival.
One previous study found that a major risk factor for perioperative death was the number of previous cardiac operations [2]. In contrast, the present population had a low perioperative mortality despite the fact that 62% of the patients had undergone at least one previous cardiac operation at the time of index TV operation.
Arrhythmias
Of the 42 patients with documentation of preoperative arrhythmias in this study, 50% of them have continued to have arrhythmias at the time of follow-up. A further 7 patients, who were in sinus rhythm preoperatively, developed late postoperative arrhythmias. Thus, it appears that many patients with atrial arrhythmias who undergo TV operation will continue to have rhythm problems postoperatively. Our study supports previous findings on a selected Ebstein population [6]. Arrhythmias remained a problem after tricuspid operation in that group, despite the fact that most patients were symptomatically improved after the operation. Indeed, it is possible that surgical scars or permanent structural modifications resulting from long-term hemodynamic stress may actually predispose adult patients with congenital heart defects to late arrhythmias. It is increasingly recognized that patch repairs of atrial septal defects and suture lines can create barriers to the transmission of electrical activation and can provide the necessary substrate for slowed conduction and intra-atrial reentrant tachycardia [12, 13]. In one series examining intra-atrial reentrant tachycardia in patients who had undergone previous operation for congenital heart disease [14], the atriotomy incision on the lateral right atrial wall frequently provided the barrier integral to sustaining the tachycardia; successful ablation in these patients was obtained at a site of early activation near a surgical anatomic defect or scar. For patients with atrial flutter/intra-atrial reentrant tachycardia, intraoperative mapping of the atrial arrhythmia coupled with cryoablation of the relevant zones of slow conduction should be considered at the time of reoperation. That such an approach is feasible, is attested to by several recent reports of successful radiofrequency ablation resulting in cure of these arrhythmias in patients with previous operation for congenital heart defects [1217]. Furthermore, modification of current surgical techniques may be required to protect against the subsequent development of intra-atrial reentrant tachycardia, for example, extension of surgical incisions to the nearest atrial orifice, and transection of the isthmus between the tricuspid annulus and inferior vena cava. In patients with chronic intractable atrial fibrillation, surgical dissection of the right atrium into electrically isolated components (modified Maze procedure) [16, 18] may be a promising future approach.
Study limitations
This study was a retrospective chart review. However, ascertainment bias was minimized by the use of data that are prospectively collected in a clinical database. The patients in this study were cared for in a tertiary care center with expertise in adult congenital heart disease surgery. Therefore, surgical expertise likely affected the excellent mortality outcomes. Because of the small sample size and the low mortality rate, it was not possible to identify risk factors for mortality.
Conclusions and clinical applications
In contrast to existing reports, in this study TV operation was associated with comparatively low perioperative and late mortality, and good long-term outcome in patients with complex congenital heart disease. Despite satisfactory hemodynamic outcome, many patients with preoperative arrhythmias will continue to require management of late arrhythmias. For a small number of patients, arrhythmias will develop late postoperatively.
Although patients may be managed with antiarrhythmic medications or pacemakers, or both, such an approach may not be ideal in the long term. In the future, patients undergoing TV operation with clinically relevant atrial arrhythmias should be considered for preoperative electrophysiologic assessment. Intraoperative ablation with cryoablation or surgical resection for atrial reentrant arrhythmias, or atrial myocardial resection (the modified Maze procedure [16, 18]) for chronic atrial fibrillation are promising future directions. These innovative techniques in conjunction with the hemodynamic improvements may lead to an improved long-term outcome for patients with congenital heart disease affecting the TV.
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| Acknowledgments |
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| References |
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