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a Department of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Science, Okayama-City, Okayama, Japan
b Cardiac Care Unit, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Science, Okayama-City, Okayama, Japan
Accepted for publication October 8, 2008.
* Address correspondence to Dr Sano, Department of Cardiac Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Science, 2-5-1 Shikata-cho, Okayama-city, Okayama, 700-8558, Japan (Email: s_sano{at}cc.okayama-u.ac.jp).
Presented at the Forty-fourth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28–30, 2008.
| Abstract |
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Methods: Twenty-five consecutive adult patients (aged 16 years or more) who underwent TCPC were retrospectively reviewed. The mean age at operation was 27 ± 9 years (range, 16 to 52). The following items were considered as the potential risk factors according to previous reports: (1) aged more than 30 years (7 of 25); (2) heterotaxy (9 of 25); (3) systemic ventricular ejection fraction less than 50% (6 of 25); (4) atrioventricular valve regurgitation moderate or greater (6 of 25); (5) pulmonary arterial index less than 200 (7 of 25); (6) mean pulmonary arterial pressure 15 mm Hg or greater (3 of 25); (7) pulmonary arterial resistance 2.0 wood units or greater (11 of 25); (8) arrhythmias (13 of 25); (9) protein-losing enteropathy (3 of 25); (10) New York Heart Association (NYHA) functional class III or greater (9 of 25); (11) previous Fontan procedure (10 of 25); (12) systemic ventricular outflow obstruction (1 of 25); and (13) end-diastolic pressure of the systemic ventricle 11 mm Hg or higher (4 of 25).
Results: The mean follow-up period was 57 ± 45 months (range, 0 to 154). All patients had at least 2 risk factors (range, 2 to 8). There was 1 early death and 2 late deaths. Comparing the late survivors and nonsurvivors, no statistical significance was identified in the above risk factors. However, the patients with 6 or more risk factors had a significantly higher mortality rate than patients with fewer than 6 risk risk factors (p < 0.01). Age (p = 0.08), NYHA class (p = 0.13), and protein-losing enteropathy (p = 0.08) may be risk factors for late death.
Conclusions: The majority of the adult TCPC candidates tolerated the TCPC procedure in the early postoperative period. However, the accumulation of risk factors influences late mortality.
| Introduction |
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In Japan, more than 300 patients have undergone the Fontan procedure annually with a hospital mortality of 3% to 4%, and approximately 10% of these patients are aged 18 years or older [9]. The TCPC procedure carries a greater risk for the adult patient than for children because the adult functional ventricle usually presents with complications caused by long-term chronic hypoxia, ventricular volume overload, and increased venous pressure, such as arrhythmia, protein-losing enteropathy (PLE), pleural effusion, ventricular dysfunction, and limited exercise capacity [10, 11]. Because heart transplantation is not a realistic surgical option in Japan owing to a very strict organ transplantation law, much more complicated adult patients with a functional single ventricle have presented to our institute. However, unlike the management of children with a functional single ventricle, management guidelines, including the preoperative predictors for mortality, have yet to be established for the adult patient who is a candidate for the Fontan procedure because few studies have so far addressed this issue. The purpose of this study was to describe the midterm to long-term outcome of adult TCPC patients and evaluate the risk factors that influence late mortality.
| Patients and Methods |
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Potential Risk Factors
Although there are still no clearly accepted criteria regarding the risk factors for TCPC, the following 13 items were considered as the potential risk factors according to previous reports [5, 12–14]: (1) aged more than 30 years; (2) heterotaxy syndrome; (3) systemic ventricular ejection fraction less than 50%; (4) atrioventricular valve incompetence moderate or greater; (5) New York Heart Association (NYHA) functional class III or greater; (6) protein-losing enteropathy (PLE); (7) redo Fontan procedure; (8) pulmonary arterial index less than 200; (9) pulmonary vascular resistance 2.0 wood units or greater; (10) significant atrial or ventricular arrhythmias; (11) mean pulmonary arterial pressure (mPAP) 15 mm Hg or higher; (12) systemic ventricular outflow obstruction (blood flow velocity measured with echocardiography
2.0 m/s); and (13) end-diastolic pressure of the systemic ventricle
11 mm Hg.
Statistical Analysis
The relationships between late mortality and these risk factors were examined with Fisher's exact test. A p value of less than 0.05 was considered to be significant.
| Results |
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Twelve patients had undergone one to three prior operations. The final conditions of these patients before the TCPC completion were post–bidirectional Glenn (BDG) procedure (n = 5), post–classical Glenn procedure (n = 2), post–aortopulmonary shunt (n = 3), and post–Ebstein's anomaly repair (n = 2: 1 tricuspid valve replacement and 1 tricuspid valve repair; Table 1). Three patients had no prior cardiac operation. The mean interval from their last operation was 162 ± 122 months (range, 2 to 348).
Twenty-three associated operations were performed, and included creation of a fenestration (n = 8), common atrioventricular valve repair (n = 1), common atrioventricular valve replacement (n = 1), Damus-Kaye-Stansel anastomosis (n = 1), pulmonary arterioplasty (n = 2), exclusion of the right atrium (n = 1), exclusion of the right ventricle (n = 2), creation or enlargement of the atrial septal defect (n = 3), modified right side Maze (n = 1), and implantation of pacemaker leads (n = 3).
There was 1 early death from cardiac tamponade due to bleeding after removal of the temporary pacing wire, and 1 late death due to heart failure. The overall mortality rate was 13.3%. The patient with a late death was a 31-year-old man who was diagnosed as having double-outlet right ventricle, common atrioventicular valve canal, pulmonary stenosis, and asplenia, and had previously undergone a right original Blalock-Taussig shunt. The patient had six risk factors: age, asplenia, pulmonary vascular resistance (3.8 wood units), NYHA class III, low ejection fraction (35%), and arrhythmia (paroxysmal atrial fibrillation). The patient was referred to our institute for a TCPC completion. Although we selected a staged operation because of his low cardiac function, his arterial blood oxygen pressure was less than 40 mm Hg after the BDG procedure, and his exercise tolerance did not improve. Hence, we performed a fenestrated extracardiac TCPC without aortic cross-clamp 2 months after the BDG procedure. In the early postoperative period, although the paroxysmal atrial fibrillation was diminished and the ventricular ejection fraction was improved to 50%, his NYHA status remained class III in the early postoperative period. Hence, synchronized biventricular pacing was applied because he had morphologically bilateral ventricles, however, it was not effective to improve his symptoms. Although he tolerated the operation well and was discharged from the hospital, he died of heart failure 9 months after the TCPC.
One patient underwent coronary arterial bypass grafting during the late follow-up period because he suffered from ventricular tachycardia due to old myocardial infarction.
Table 4 shows the clinical courses of the arrhythmias. Six patients had some sort of paroxysmal tachyarrhythmia before TCPC. One patient underwent a modified right-side Maze procedure for paroxysmal atrial fibrillation concomitant with TCPC. This patient had no recurrence of paroxysmal atrial fibrillation during the late follow-up period. In 3 patients, preoperative tachyarrhythmia disappeared in the late follow-up period. One patient had an episode of new-onset atrial tachyarrhythmia temporarily. One patient underwent pacemaker implantation for sick sinus syndrome in the early postoperative period. One patient showed a new onset of sick sinus syndrome in the late postoperative period without any symptoms.
Figure 1 shows the changes of NYHA class status during the late follow-up period after a TCPC completion. Seven patients had an improved NYHA class. Seven patients are in NYHA class I at present, and 6 patients are in NYHA class II after the operation. Although 4 patients needed home oxygen therapy in the early postoperative period (Table 5), all of them were weaned from home oxygen therapy, except for the patient who had a late death.
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All patients underwent one to four prior operations including the Fontan procedure. The previous Fontan procedures were an atrial-pulmonary connection (n = 4), atrial-pulmonary connection with oblique partition of the right atrium (n = 1), right atrium to pulmonary arterial graft (n = 3), Kreutzer procedure (n = 1), and a lateral tunnel (n = 1; Table 1). The mean duration from their previous Fontan procedure was 185 ± 50 months (range, 92 to 275).
Twenty-one associated operations were performed, which included the creation of a fenestration (n = 5), tricuspid valve repair (n = 1), tricuspid valve closure (n = 1), subaortic muscle resection (n = 1), pulmonary arterioplasty (n = 2), exclusion of the right ventricle (n = 1), enlargement of atrial septal defect (n = 1), thrombectomy of right atrium (n = 1), modified right side Maze (n = 2), implantation of pacemaker leads (n = 5), and pacemaker generator exchange (n = 1).
There was 1 late death due to hepatic failure. The overall mortality rate was 10.0%. The patient who had a late death was a 31-year-old man who was diagnosed as having a corrected transposition of the great arteries, mitral atresia, pulmonary stenosis, ventricular septal defect, and atrial septal defect. This patient underwent a Kreutzer procedure when he was 9 years old. The patient had eight risk factors: age, moderate atrioventricular valve regurgitation, NYHA class III, pulmonary arterial index (176), arrhythmia (paroxysmal atrial fibrillation), PLE, a previous Fontan procedure, and end-diastolic pressure of the systemic ventricle (11 mm Hg). In addition, he had chronic hepatic failure with ascites due to chronic hepatitis C infection and congestive heart failure. The patient was referred to our institute for TCPC conversion to improve these symptoms. Although this patient was considered to be a very high risk case for heart surgery, he underwent the TCPC conversion according to his strong desire because his hepatic functional reserve was proved to be enough by 99mTc-galactosyl human serum albumin (GSA) liver scintigraphy. After the TCPC conversion, the ascites and PLE were improved, and the serum total protein and albumin in this patient were increased, respectively, from 4.5 mg/dL and 2.2 mg/dL to 5.2 mg/dL and 2.8 mg/dL. The NYHA functional class improved to II. He tolerated the operation well and was discharged on postoperative day 43. However, he suddenly died of an acute worsening of his hepatic failure 4 months after the TCPC conversion.
There was one reoperation during the late follow-up period. This patent underwent mitral valve repair and creation of fenestration because of the new onset of PLE (Table 5) with moderate mitral valve regurgitation. The PLE disappeared after the operation.
Eight patients had sinus rhythm, and 2 patients had chronic atrial fibrillation preoperatively. Seven patients had some sort of paroxysmal tachyarrhythmia before the TCPC conversion. Two patients underwent a modified right-side Maze procedure concomitant with the TCPC conversion. One of these 2 patients had no recurrence of paroxysmal atrial flutter, and the other patient had a recurrence of paroxysmal atrial tachycardia needing medication during the late follow-up. Two patients with chronic atrial fibrillation did not undergo any arrhythmia surgery, because of no atrial fibrillation wave on the electrocardiogram (patient 18), and because of the need to avoid longer aortic cross-clamp time and cardiopulmonary bypass time owing to numerous risk factors (patient 23). In 5 patients, the preoperative atrial tachyarrhythmia disappeared on the late follow-up, and 4 of the 5 patients needed no antiarrhythmic agent. There was no new onset of tachyarrhythmia. One patient underwent pacemaker implantation for sick sinus syndrome during the early postoperative period. Two patients underwent pacemaker implantation during the late postoperative period for sick sinus syndrome and complete atrioventricular block, respectively (Table 4).
Figure 2 shows the changes of NYHA functional class during the late follow-up after the TCPC conversion. Seven patients had improved NYHA class; 5 patients are in NYHA class I at present, and 5 patients are in NYHA class II after the operation. No patient required home oxygen therapy (Table 5).
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| Comment |
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In this study, although there was no significant risk factor for late death, a significantly high mortality rate was found for patients who had six or more risk factors. In addition, the patients who survived more than 1 year after the TCPC could survive long term without new onset of arrhythmia or deteriorating exercise tolerance. These results indicate that if TCPC completion or TCPC conversion had been performed earlier in patients who experienced late deaths, both patients could have survived for a long time with an excellent quality of life. In our opinion, to improve quality of life and long-term prognosis, TCPC completion should therefore be performed as soon as possible once a patient has been clearly indicated as requiring it, and TCPC conversion should be performed at an early stage of the morbidities.
Although patients with PLE had a poor prognosis [18], they could potentially thereafter completely recover if the cause of PLE is released in the early stage. It is interesting to note that 1 of our patients underwent fenestration and mitral valve repair during the follow-up period after the TCPC because this patient had a new onset of a PLE with severe mitral regurgitation. The PLE completely disappeared after the operation. Performing a TCPC before the onset of PLE must therefore be one of the important considerations for an excellent prognosis after an adult TCPC.
The NYHA status also improved in most of the patients in this study, as described in previous reports [16, 17]. The patients in NYHA class III could become NYHA class I after the TCPC. However, both patients who had late deaths were in NYHA class III. If possible, surgical intervention should be performed before NYHA functional class deteriorates to class III.
Eighty percent of the patients in this series had no atrial tachyarrhythmia on late follow-up. Seventy percent of preoperative atrial tachyarrhythmia ha disappeared. Only 1 patient had a new onset of atrial tachyarrhythmia after the TCPC. The incidence of atrial tachyarrhythmia on late follow-up period in this study was lower than that of the previously reported adult Fontan study, which mainly included an atriopulmonary connection [10, 12]. Our first case of arrhythmia surgery concomitant with TCPC in adult patients was performed in 2003. There were 3 patients who underwent a modified right Maze procedure in this series. The modified right Maze procedure is an effective procedure for high-risk adult patients with atrial flutter or fibrillation. Although the Cox-III Maze procedure has been reported to be a more effective procedure for atrial fibrillation for adult TCPC conversion [19], we have not yet performed it because the patients were either not indicated to undergo this procedure or because an attack of atrial fibrillation had not occurred so often, owing to our early surgical intervention. Arrhythmia surgery concomitant with TCPC will increase hereafter because the number of patients with ill-disposed atrial arrhythmia will increase. Although we also analyzed the relationship between atrial arrhythmia and the previously described risk factors, no significant differences were observed.
As mentioned above, no criteria have yet been established for patients to undergo TCPC completion or for TCPC conversion in adults. We think that a careful and multidisciplinary risk analysis is the only way to determine the indications for this procedure. However, mean pulmonary artery pressure of 20 mm Hg or higher is presently our only contraindication to TCPC, not only for adults but also for children. In our institute, there has so far been no clear contraindications for adult TCPC completion and TCPC conversion. We believe that the following criteria, namely, mean pulmonary vascular resistance of 4.0 wood units, pulmonary arterial index of 150, and ejection fraction of 40% are usually acceptable. Although orthotopic heart transplantation is not a realistic choice in Japan, we will consider the possibility of it for patients with severe systemic ventricular dysfunction that cannot be controlled with medication. The establishment of methods to accurately assess this patient population, such as the scoring of risk factors, is thus called for in future investigations.
In conclusion, TCPC could be offered to high-risk adult Fontan candidates, with an acceptable mortality rate. Both the TCPC completion and the TCPC conversion improved the patients' arrhythmia and NYHA functional class. Most of the adult TCPC candidates tolerated the TCPC during the early postoperative period. However, the accumulation of risk factors may influence their late mortality. To improve the late clinical outcome for this patient population, early TCPC completion or conversion is therefore required before complications occur.
| Discussion |
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DR SANO: Out of 25 patients, we have 2 patients who had one-lung Fontan. Both patients previously underwent a left-sided modified-BT shunt in another unit. One patient underwent a modified-BT shunt to the left pulmonary vein. And another patient had the original Glenn at another institution and was then referred to us. Both patients had very good right lung. And the Nakata index with only one lung was about 180 to 190 with a mean PA pressure of 9 to 11 mm Hg. Even if the patients have only one-lung physiology, however, all the parameters are indications for Fontan; we do a Fontan because there is almost no chance of heart transplantation in Japan. That's why we decided to do a Fontan. And both patients are doing quite well postoperatively.
DR BACKER: The other question I had was about the patients with PLE. It is very daunting to attempt a Fontan reoperation on a patient who already has protein-losing enteropathy. It sounds like some of those patients actually did well with this.
DR SANO: Three patients had a long-standing PLE. Those patients underwent a so-called classical Fontan. After conversion to an extracardiac TCPC with fenestration, 1 patient has improved his PLE; however, he still has PLE. Severity is completely different. He used to have a protein infusion every day, and after conversion, his protein infusion is once in 1 to 2 weeks. In the second patient, PLE completely disappeared. Third patient died of tamponade and shock after conversion.
DR BACKER: So those are patients who had an atriopulmonary Fontan and then you converted them to an extracardiac Fontan with a fenestration; is that correct?
DR SANO: Yes.
DR BACKER: Why don't we survey the audience. What do surgeons think about doing a Fontan where there is only "one lung"? How many people would be comfortable doing what we call a one-lung Fontan if the pulmonary artery pressure and resistance were adequate? Let's see a show of hands. Looks like a little over 50% of the audience.
DR JOSEPH M. FORBESS (Dallas, TX): How about another show of hands. How many people would be comfortable doing Fontans on the patients on the northern side of the bell curve here without the possibility of transplantation, which is, am I to interpret, the environment in which you were working?
DR SANO: Yes.
DR FORBESS: I think that's fairly admirable to be taking on these patients. It looks like you've achieved quite nice results.
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