Renewal of the Fontan circulation with concomitant surgical intervention for atrial arrhythmia

Long-term therapeutic effect of Fontan conversion with an extracardiac conduit

OBJECTIVES

The aim of this study was to identify the long-term therapeutic effect of total cavopulmonary connection (TCPC) conversion with an extracardiac conduit.

METHODS

Between 1991 and 2014, 36 patients underwent TCPC conversion with an extracardiac conduit. Half of these patients were diagnosed with tricuspid atresia or its variant. The left ventricle was dominant in 26 patients (72.2%). Median age at conversion and interval from initial Fontan operation to conversion were 24.1 years (interquartile range 18.9-29.2) and 17.8 years (15.4-20.9), respectively. Surgical cryoablation was concomitantly performed in 32 patients (88.9%). Cardiac catheter examination was performed preoperatively (36 patients, 100%) and at 1 year (31 patients, 86%), 5 years (25 patients, 69%) and 10 years (13 patients, 36%) after TCPC conversion. Symptom-limited treadmill exercise with expired gas analysis was performed preoperatively (32 patients, 88.9%) and at 1 year (27 patients, 75.0%), 5 years (20 patients, 55.6%) and 10 years (12 patients, 33.3%) after conversion.

RESULTS

All patients received follow-up; the mean follow-up period was 8.2 ± 4.8 years. Actuarial survival rate, protein-losing enteropathy-free survival rate and rate of survival with sinus rhythm maintenance at 10 years were 79.2%, 67.8% and 48.5%, respectively. The survival curve declined steeply when the duration of Fontan circulation exceeded 25 years. New cases of protein-losing enteropathy developed postoperatively in 2 patients. Permanent pacemakers were implanted in 12 patients (33%), but atrial tachyarrhythmia was not sustained in any of the remaining patients. Pulmonary arterial pressure (11.0 ± 3.1 to 9.5 ± 3.6 mmHg, P = 0.003), pulmonary vascular resistance (2.1 ± 0.7 to 1.3 ± 0.5 WU/m2, P < 0.0001) and cardiac index (2.0 ± 0.3 to 2.9 ± 0.6 l/min/m2, P < 0.0001) significantly improved from preoperative evaluation to 1 year after the conversion, and these improvements were maintained during the entire follow-up period. Peak oxygen uptake remained unchanged from the preoperative evaluation (49.7 ± 11.5% predicted) to 1 year (52.5 ± 12.0%), 5 years (56.2 ± 9.6%) and 10 years (51.2 ± 9.4%) after conversion (P = 0.19).

CONCLUSIONS

Owing to its anti-arrhythmic effect and Fontan pathway recruitment effect, TCPC conversion with an extracardiac conduit prevented the natural decline of exercise tolerance that is seen in classic Fontan patients.

Surgical aspects of atrial arrhythmia : Right atrial ablation and anti-arrhythmic surgery in congenital heart disease

BACKGROUND

Atrial arrhythmias are frequently described in congenital heart disease.

OBJECTIVES

To provide a surgical perspective of anti-arrhythmic procedures and strategic approaches.

METHODS

Discussion of the history of anti-arrhythmic treatments in congenital heart disease.

RESULTS

Before the advent of the Maze procedure (first published in 1991), surgery mainly focused on patients with Wolff-Parkinson-White syndrome and also on arrhythmias in Ebstein's malformation. Atrial septal defects (ASD) subsequently received more attention, i.e., in terms of atrial arrhythmia in the natural prognosis and the surgically modified course and in terms of surgical versus transcatheter approaches. Based on the background of various atrial arrhythmia mechanisms of ASD, several surgical procedures have been reported, ranging from the bilateral full Maze procedure to simple modification of right atriotomy. The so-called right atrial Maze procedure occupies a special position from the viewpoint of cardiology in acquired heart disease, especially in cases of frequently occurring right heart failure. In hearts with more complex structural abnormalities, a detailed understanding of the conditions to improve overall surgical outcome and develop future "anti-arrhythmic" strategies is necessary.

CONCLUSIONS

It is important to precisely specify factors in the individual cases, not only morphological diversity but also technical and strategic variations and their consequences. A variety of anti-arrhythmic surgical procedures are currently available. How and when to use which procedure requires professional insight and cautious clinical decision-making.

Fontan Conversion

Early survival after the Fontan operation has improved significantly leading to a lifetime of Fontan circulation for patients. There is a natural progression of pulmonary artery pressure during the human lifetime that is easily tolerated in two-ventricle physiology but is deleterious for single-ventricle physiology. Obstructions in the venous to pulmonary artery pathway and pulmonary venous return or ventricular outflow, atrioventricular valve dysfunction (regurgitation), pulmonary arteriovenous malformations, venous thrombosis, and the development of atrial arrhythmias can lead to reduced functional status. These complications have been demonstrated in older patients with largely atriopulmonary connections owing to time accrual and unfavorable flow characteristics. Various surgical and catheter interventions aimed at reducing morbidity and mortality have been attempted to treat these identifiable abnormalities. The purpose of this article is to review the extant literature on Fontan Conversion and to assess the lessons learned over 20 years.

Fontan conversion with concomitant arrhythmia surgery for the failing atriopulmonary connections: mid-term results from a single centre

OBJECTIVES

Classical Atriopulmonary Fontan connections tend to fail in the long term due to progressive anastomotic site obstruction, right atrial enlargement, and refractory atrial arrhythmias. Conversion to total cavopulmonary connection with concomitant arrhythmia surgery is a promising treatment but optimal timing of the procedure remains controversial.

METHODS

Between the years 2002 and 2009, 15 patients with a median age of 26.2 (12-43) years underwent Fontan conversion operation with concomitant arrhythmia surgery. All were symptomatic and 14 out of the 15 patients had refractory arrhythmias. The duration of pre-operative arrhythmia and the outcome of surgery were correlated to study the impact of delay in surgical intervention on post-operative survival and arrhythmia control.

RESULTS

There were two patients who died in the early post-operative period (13.3%). At the mid-term follow-up, 53 (20-86) months, late atrial arrhythmias had recurred in two of the 13 surviving patients (15.30%) and one patient developed late sinus node dysfunction. The need for anti-arrhythmic drugs decreased considerably from 93.5% to 15.3% on mid-term follow-up. There was no late death or need for cardiac transplantation. The duration of arrhythmia before surgery was prolonged for more than 10 years in patients who died as well as in those who had complications like late recurrence of arrhythmias, dependence on anti-arrhythmic medications, and worsening of ventricular dysfunction.

CONCLUSIONS

Fontan conversion is a well-established treatment option for salvaging the failing atriopulmonary connections. Concomitant arrhythmia surgery effectively resolves the refractory atrial arrhythmias and improves survival, but we need to optimise the timing of Fontan conversion to improve the long-term outcome.

Mid-term results following surgical treatment of congenital cardiac malformations in adults

The long term consequences of untreated of residual or recurrent lesions pose unique challenges in the growing population of adults with congenitally malformed hearts. In our unit, 335 patients aged from 18 to 72 years, with a mean age of 35 plus or minus 14 years, presented for correction of congenital cardiac disease from September, 1997, through December, 2006. Of the group, 42 (12.5%) had undergone one or more prior surgical procedures, 3 were admitted as emergencies, and a further 10 (3%) had suffered prior cardiac related complications. Symptoms had been noted by 181 patients (54%), and 42 (12.5%) had an established arrhythmia. Chromosomal anomalies were identified in 13 (3.8%), and diagnostic catheterisation was required in 201 (60%) patients. Of the overall group, 2 patients died early (0.6%). Complications occurred in 61 patients (18%), including atrial fibrillation, pneumothorax, postoperative haemorrhage, pericardial or pleural effusions requiring drainage, stroke, complete heart block, endocarditis, wound dehiscence, and peripheral neuropathy. The median length of stay in the intensive care unit and hospital were 2 and 7 days, respectively. Death occurred later in 2 further patients (0.6%), due to atrial fibrillation and pulmonary hypertension. At mean follow-up of 63 plus or minus 30 months, the majority of the remaining patients are well with resolution or significant improvement in their symptoms. Despite the long term deleterious effects of untreated, residual or recurrent congenital cardiac lesions in adults, therefore, we conclude that surgical correction can be achieved with low mortality and acceptable morbidity. Most significant complications are related to arrhythmias.

Conversion to total cavopulmonary connection after failed one and one-half ventricular repair

In 3 patients previously undergoing one and one-half ventricular repair, right ventricular dysfunction progressed for more than 10 years. Their clinical features resembled those seen in patients undergoing the atriopulmonary Fontan procedure, and reoperation was carried out for conversion to total cavopulmonary connection. Hemodynamics improved subsequent to the circulatory renewal. In 2 patients having atrial arrhythmia before conversion, the resected right atrial wall illustrated grossly abnormal histopathology. These patients suffered from persistent sinus nodal dysfunction and eventually needed pacemaker implantation. The third patient died of sepsis 4 months later.

Optimal timing of the Fontan conversion: change in the P-wave characteristics precedes the onset of atrial tachyarrhythmias in patients with atriopulmonary connection

OBJECTIVES

Atrial tachyarrhythmia is a common complication late after the atriopulmonary connection Fontan procedure. The P-wave duration and dispersion have been regarded as useful markers for its prediction. The purpose of this study was to analyze change in the P-wave characteristics over time after the atriopulmonary connection Fontan procedure, with a special emphasis on the timing of the Fontan conversion.

METHODS

We reviewed clinical and electrocardiographic data in 18 patients with classic tricuspid atresia who underwent the atriopulmonary connection Fontan procedure. Their median age at operation was 4.1 years (range, 1.1-22 years), and the median follow-up period was 18.1 years (range, 10-25 years). We measured the P-wave duration, dispersion, and axis from consecutive 12-lead electrocardiograms in each patient.

RESULTS

There was a significant increase in the maximum P-wave duration as well as the P-wave dispersion over time. Transient ectopic atrial rhythm was observed in 16 patients during follow-up. Atrial tachyarrhythmia developed subsequent to transient ectopic atrial rhythm in 8 patients. Ten patients underwent the conversion. Atrial tachyarrhythmia recurred in 2 patients who had sustained arrhythmia (6.0 and 8.0 years) before the conversion. In contrast, the other 8 patients with transient ectopic atrial rhythm alone or nonsustained atrial tachyarrhythmia have been free from arrhythmia after the conversion.

CONCLUSIONS

Patients commonly and increasingly had prolonged P-wave duration, larger P-wave dispersion, and ectopic atrial rhythm, along with an atrial tachyarrhythmia propensity, late after the atriopulmonary connection Fontan procedure. These P-wave characteristics were informative when considering the Fontan conversion before a sustained atrial tachyarrhythmia ensued.

Extracardiac Fontan procedure bridging the vertebra for apico-caval juxtaposition

For 5 patients with univentricular heart associated with apico-caval juxtaposition, an extracardiac Fontan procedure was carried out using an artificial graft bridging the vertebra to avoid graft compression by the vertebra and the ventricle. For 2 patients representing nonconfluency between the inferior caval vein and the hepatic vein, a hand-made, shoe-tree graft was used. Postoperatively all patients are doing well without a stenotic venous pathway. This extracardiac operation using an artificial graft bridging the vertebra may be advantageous for univentricular heart associated with apico-caval juxtaposition to prevent a postoperative stenotic venous pathway.

Late complications associated with the Fontan circulation

The recent significant reduction in operative mortality associated with surgical completion of the Fontan circulation is clearly multi-factorial. Better understanding of the fundamental physiological and anatomical issues have led to refinements in operative technique, early neutralization of potential risk factors, widespread use of a staged approach, and selective application of the concept of fenestration or incomplete partitioning. While further reduction of operative mortality is important, and may be anticipated in the future, major emphasis now must be placed on optimizing functional outcome, and understanding and managing the late complications associated with the unique physiology produced by the Fontan circulation.

Surgery for arrhythmias in children

BACKGROUND

Transcatheter radiofrequency ablation to treat supraventricular and ventricular arrhythmias has supplanted routine surgical ablative therapy and redefined its role. A small population of arrhythmia patients now requires surgical ablation: those who have failed catheter ablation, patients with concomitant congenital heart disease in association with arrhythmias, those with atrial fibrillation and very young patients for whom transcatheter techniques are prohibitive because of small size, cyanosis or distorted anatomy.

METHODS

From July 1992 through August 2003, 133 patients underwent arrhythmia surgery at Children's Memorial Hospital, 50% (67/133) in association with Fontan conversion (FC), 22% (28/133) with concomitant initial Fontan (IF) procedure and 28% (38/133) for various arrhythmias (MISC) in patients with (36/38, 95%) or without (2/38, 5%) associated structural heart disease. Mean age at surgery in the FC group was 20+/-7.6 years (median 19 years), and in the IF group and the MISC group, mean ages were 8.1+/-8.9 (median 4.2) years and 16.4+/-10.9 (median 11.3) years, respectively.

RESULTS

There were three operative (3/133, 2.6%; 1 FC, 2 MISC) and three late deaths (2 FC, 1 MISC). Four patients in the FC group had progressive ventricular failure and underwent successful cardiac transplantation. Follow-up data are available for non-transplant, surviving patients and reveal 11 incidences of persistent arrhythmia recurrence and 2 new-onset arrhythmias. Five of the 11 recurrences occurred early in our series of FC patients, when isthmus block interruption of arrhythmia foci was performed. Four additional recurrences occurred later in the FC series, two post-maze and two post-Cox-maze III. In the MISC group, there were two recurrences. Atrial reentry tachycardia (ART) recurred in a patient with no structural heart disease and accessory connection-mediated tachycardia recurred in a child who underwent concomitant initial Fontan. Two patients had ventricular tachycardia inducible at postoperative studies (2/7, 29%), but no clinical recurrence. Two new-onset tachycardias occurred, one child developed ART post-surgical ablation of accessory connections and one patient with inducible ventricular tachycardia developed ART 5 years postoperatively.

CONCLUSION

Variations in atrial and ventricular anatomy that may limit the catheter approach can be addressed surgically. Patient size or anatomic complexity should not be limiting factors in the combined surgical arrhythmia approach. Incorporation of arrhythmia therapy into planned surgical revision should be considered.

Surgical treatment of arrhythmias related to congenital heart diseases

BACKGROUND

Supraventricular arrhythmias complicate operated and unoperated congenital heart disease, especially when atrial dilatation coexists.

METHODS

We evaluated the results of intraoperative ablation in a group of 23 patients with chronic supraventricular tachyarrhythmias (mostly intraatrial reentry) that were unresponsive to conventional medical therapy. All procedures were performed consecutively between September 1999 and November 2001. Ablation was done during redo operations (Fontan conversion to total cavopulmonary connection in 16 patients) in 18 patients and during primary surgical correction in 5 patients. The mean age at operation was 25 +/- 12 years (2 to 50 years). Cryoablation was done in 10 patients and radiofrequency ablation in 13 patients. Nineteen patients had ablation in one atrium and 4 had ablation in both atria. A generous atrial reduction was always performed at the end of the operation.

RESULTS

The operative mortality rate was 13% (3 patients) from causes unrelated to ablation. In 20 survivors, the ablation was effective immediately. Eight patients required a permanent pacemaker. During a mean follow-up of 22 +/- 4 months, atrial arrhythmias recurred in 25% (5 patients) and were controlled with medical therapy, whereas 1 patient required pacemaker implantation.

CONCLUSIONS

Intraoperative treatment of unresponsive atrial tachyarrhythmias associated with operated or unoperated congenital heart disease is feasible and the midterm results are encouraging.

Role of catheter and surgical ablation in congenital heart disease

The role of surgery and radiofrequency current ablation for the treatment of tachycardias in patients with congenital heart disease The use of radiofrequency current application as a treatment strategy has stimulated a revolution in our understanding of tachycardia mechanisms. The extension of its use to patients with congenital heart defects and tachyarrhythmias has opened the door to new treatments with known success rates and known risks for mortality and morbidity. Antiarrhythmic surgery aims to dissect or excavate a responsible substrate and is especially worth considering if cardiac surgery is being undertaken for other reasons. With suitable surgical skill and interest, and with strong electrophysiologic support, high success rates have been documented. Antiarrhythmic surgical incisions have the advantage of being visually controllable regarding the extent and location of damage to myocardial tissue. In other situations, radiofrequency current ablation is preferred because of its less-invasive character, its use of local anesthesia, and the avoidance of surgical trauma. Both surgery and catheter ablation require precise clarification of the tachycardia mechanism and precise localization of the underlying substrate. The importation of such techniques into the realm of open chest surgery would be difficult in light of the need for multiple intracardiac catheters and repeated fluoroscopically guided catheter positioning. Electrophysiologic studies performed during the antiarrhythmic surgical procedure cannot provide complete information, and their use is thus restricted to the arrhythmogenic myocardial target only [32,45]. In contrast, catheter-mediated electrophysiologic studies offer the option of exact diagnosis, precise substrate localization, and interventional treatment in a single session. Moreover, validation of the linear lesion's completeness has become a reliable predictor for mid- and long-term success in avoiding recurrences. As a result, the application of catheter-mediated ablation has exploded within the past 15 years. Antiarrhythmic surgery has survived as a discipline in a decreasing number of experienced hands [43,44]. As a result of recent experiences and modern technology, success rates above 90% [74-76, 81,88] for the interventional treatment of congenital tachycardias have become comparable to those reported in patients with "normal" hearts. For acquired tachycardias, acute success rates today range about 80% at the atrial level. The rate of recurrence is still relatively high at about 10-25% [73,76,77,79,91,96,102]. Further improvements are being pursued. Data on the treatment of acquired tachycardias at the ventricular level is largely anecdotal. Good early success rates are combined with a tendency to recurrence in longer-term follow-up [50,76,103-108]. Some of the late VT ablation recurrences may be explained by the fact that fibrotic, scarred, and hypertrophic myocardial tissue at the targeted site often prevents effective radiofrequency current application and lesion generation. In order to improve RF lesion depth and continuity, newly designed technologies for radiofrequency current ("cooled tip electrode", Cordis Webster, Baldwin Park, CA), and alternative energy sources (cryo-ablation, micro-wave, or ultrasound) are being readied for introduction in the very near future. For patients suffering from recurrent tachycardias and having other reasons for open-heart surgery, a hybrid concept can be created, utilizing modern 3-D electro-anatomical reconstruction as a basis for an electrophysiologically informed surgical procedure. Following such a concept, a hemodynamic catheterization can be combined with an electrophysiologic study to define critical myocardial zones for induced macro-re-entry tachycardias, or of those zones expected to play an arrhythmogenic role in the future. With such information, surgical incisions for cardiac access and repair can be planned and performed. The role of surgery in antiarrhythmic treatment can become preventive. Myocardial tissue is incised for cannulation and repair in a way that can reduce the chance of later scar-associated tachycardias [109]. The extension of surgical cuts to physiologic barriers of electrical conduction is a major strategy for the primary prevention of postsurgical or incisional arrhythmias. In addition, the simultaneous treatment at heart surgery of already existing tachycardias can be offered within the same session as a secondary preventive concept. Despite the immense growth of knowledge and experience in recent years, there is still a need for more knowledge about the factors causing arrhythmogenesis and their interactions. Prospective and randomized studies are needed to show the most effective strategies to prevent arrhythmia-mediated death. The future of antiarrhythmic treatment will less be directed by the limitations of current interventional tools, which will be improved, and more by an evolutionary process in philosophy regarding the understanding of arrhythmogenesis in these patients as the basis for new concepts of arrhythmia prevention and treatment.

Functional status in adolescents and adults with Fontan circulation

OBJECTIVE

We determined functional status in adolescents and adults with Fontan circulation.

METHODS

Functional status was studied in 25 patients surviving more than 2 years after the definitive procedure and currently no younger than 18 years old. Age at operation was 2 to 44 years old, and follow-up was 12 +/- 5 years. To achieve Fontan circulation, atriopulmonary connection was used in 14 patients, and total cavopulmonary connection in 11 patients.

RESULTS

One patient undergoing atriopulmonary connection died suddenly 6 years after the Fontan procedure due to pulmonary thromboembolism. New York heart association functional status was class I in 23, and class II in 2, at the latest follow-up. Catheterization done 6.5 +/- 6.8 years after the Fontan procedure showed that systemic venous pressure was statistically higher (p = 0.019) in the atriopulmonary connection group (13 +/- 3 mmHg) than in the total cavopulmonary connection group (10 +/- 3 mmHg). Exercise tests in 19 patients showed reduced tolerance in all, with maximal oxygen intake being 24.4 +/- 5.1 ml/kg/min. Serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were elevated above normal in 11 (44%). Arrhythmia was noted over longer terms in 4 patients undergoing atriopulmonary connection; in 3, atriopulmonary connection was converted to total cavopulmonary connection, and surgical intervention for atrial arrhythmia was successful.

CONCLUSION

Although functional status in adolescents and adults with Fontan circulation was good, arrhythmia and liver dysfunction in such subjects could lead to morbidity.

Individualized total cavopulmonary connection technique for patients with asplenia syndrome

BACKGROUND

Outcomes after univentricular repair for patients with asplenia syndrome remain unsatisfactory, not only because of clinical difficulties in patient selection, but also secondary to technical difficulties in the separation of the systemic and pulmonary circulations, particularly with the rerouting technique for the inferior systemic veins.

METHODS

Between February 1995 and May 2000, a total of 14 consecutive patients with asplenia syndrome underwent bidirectional cavopulmonary connection with obliteration of additional pulmonary blood flow, followed by a total cavopulmonary connection. The rerouting technique for inferior systemic venous blood flow was individualized to optimize laminar nonturbulent flow characteristics in the pathway, and to minimize prosthetic load and suture load on the atrial wall. The lateral tunnel or tube conduit technique was used in an extraatrial, intra-extraatrial, or intraatrial fashion. No fenestration was applied.

RESULTS

No hospital mortality was observed. Systemic venous flow was evaluated using magnetic resonance angiography, revealing no signs of obstruction, turbulence, or stasis either in or near the reconstructed pathways, irrespective of the rerouting technique. Postoperative catheterization revealed favorable hemodynamics including an inferior vena cava pressure of 13 +/- 2 mm Hg and arterial oxygen saturation of 93.4% +/- 3.5% at room air. All patients have remained free of symptoms, although 1 patient died of acute septic complications 3.5 years after the procedure.

CONCLUSIONS

The complexity of cardiac anomalies in asplenia syndrome warrants individualization of the total cavopulmonary connection technique used in reconstruction of the inferior systemic venous pathway. Optimizing flow characteristics in the pathway should be a priority. A staging approach allows suitable selection of candidates for univentricular repair.