Equivalent survival following cavopulmonary shunt: with or without the Fontan procedure

Francis Fontan (1929-2018): Pioneer pediatric cardiac surgeon

Up until the mid-1900s, tricuspid atresia - a birth defect of the tricuspid valve, was once categorized as a "death sentence." The challenge of achieving positive health outcomes for affected patients was compounded by a hesitancy to operate on children. The main concern was safely administering anesthesia to young patients who were going through a strenuous operation that was often poorly tolerated. Despite these assumed limitations, Francis Fontan, a pediatric cardiothoracic surgeon at the Hospital of Tondu in Bordeaux, was able to redirect blood flow from the superior and inferior vena cava to the pulmonary arteries in 1971, which elucidated the process of advancing clinical practice in medicine. With the support of mentors and a firm belief in this new technique, Fontan pioneered his eponymous procedure and ultimately paved the way for modern cardiovascular surgical techniques that helped to prolong the life of those with single functioning ventricles. The aim of this study is to examine the genesis and the evolution of the Fontan procedure to elucidate the process of advancing clinical practice in medicine by utilizing personal interviews, Fontan's works, associated primary and secondary sources in the context of 20th century cardiothoracic surgery and innovations.

A practical guide to echocardiographic evaluation of adult Fontan patients

Recent advances in surgical techniques and perioperative care for patients with single ventricle physiology have led to a remarkable improvement in long-term survival, such that now the majority of patients with single ventricle physiology are living to adulthood after Fontan palliation. The management of adult patients with Fontan physiology is one of the most challenging clinical dilemmas encountered in contemporary cardiology. The complex and heterogeneous anatomical and physiological abnormalities seen in Fontan patients mandate that any clinical evaluation, either for routine follow-up or preoperative evaluation prior to any transcatheter or surgical intervention, incorporates detailed information from a careful and thorough echocardiographic examination, These examinations, however, can be complex and confusing, even for experienced echocardiographers. Ideally, the interpretation of these studies is informed by an understanding of the basic anatomical lesions and of the potential long-term complications encountered in adult single ventricle patients. In this review, we present a practical and clinically oriented approach to the echocardiographic evaluation of adult patients with single ventricle physiology post-Fontan.

Fate of patients with single ventricles who do not undergo the Fontan procedure

BACKGROUND

The Fontan procedure, the last of a series of palliative operations for patients born with single ventricles, is associated with a significant late burden of complications. There are other strategies for patients who are suboptimal candidates for Fontan completion, however the long-term outcomes of these different surgical options have not been clearly elucidated. We performed a systematic literature review to establish the current role of other treatment approaches besides the Fontan procedure.

METHODS

MEDLINE and Embase databases were systematically searched for articles describing the long-term outcomes of patients with single ventricles who have not received the Fontan procedure.

RESULTS

A total of 36 articles met all inclusion criteria. There is a scarcity of contemporary data on the non-Fontan cohort. Historical studies provided a significant contribution.

CONCLUSIONS

Long-term survival in unoperated patients with single ventricles is possible under the rare conditions of having balanced hemodynamics. Up to half of patients may survive on only a systemic-to-pulmonary artery shunt or bidirectional cavopulmonary shunt for over 20 years with reasonable functional status. In patients with a failing single ventricle, the bidirectional cavopulmonary shunt is an excellent bridge to heart transplantation and may provide better post-transplant survival than those with a Fontan circulation. Currently, the Fontan procedure continues to be the best definitive palliation for patients born with single ventricle lesions. However, for those with borderline indications, other strategies should be carefully considered.

Outcome of the Glenn procedure as definitive palliation in single ventricle patients

OBJECTIVES

In selected single ventricle patients, a Glenn procedure (SV-Glenn) may be considered as definitive palliation. Either the patient is unsuited to progress to a Fontan circulation or a SV-Glenn circulation is preferred. This study aimed at describing the clinical course, and long-term mortality/morbidity of SV-Glenn patients.

METHODS

All SV-Glenn patients followed at the University Hospitals Leuven before May 2018 were included. Patients who underwent, or were awaiting, TCPC completion and those who underwent a Glenn in the setting of a biventricular circulation one-and-a-half repair (OAHR), were excluded.

RESULTS

Of 65 Glenn-only patients identified, 21 (32%) had OAHR, whereas 44 (68%) were SV-Glenn patients. Of SV-Glenn patients, 19 died within 6 months after the Glenn procedure. Of 25 SV-Glenn survivors, median age at Glenn was 6.3 (IQR 1.2-29.7) years. Eight were unsuited for TCPC completion; in 17 SV-Glenn was preferred over TCPC completion. Over a median follow-up time of 11 (IQR 3-18) years after the Glenn procedure, 5 (20%) patients died. At latest follow-up 10 (40%) had heart failure, 5 (20%) had atrial and 4 (16%) ventricular arrhythmias, 2 (8%) a thromboembolic event, 7 (28%) required pacemaker implantation, and 2 (8%) had infective endocarditis but none developed cirrhosis or protein-losing enteropathy. Mean saturation at latest follow-up was 87 ± 7%.

CONCLUSION

SV-Glenn patients represent a unique and heterogeneous patient population. Outcome was reasonable, although comorbidities, such as heart failure and arrhythmias were not uncommon. In SV-Glenn patients, 'classic' complications related to Fontan physiology, such as cirrhosis and protein-losing enteropathy, were absent.

Frontiers in Fontan failure: Innovation and improving outcomes: A conference summary

The initial "Frontiers in Fontan Failure" conference in 2015 in Atlanta, GA, provided an opportunity for experts in the field of pediatric cardiology and adult congenital heart disease to focus on the etiology, physiology, and potential interventions for patients with "Failing Fontan" physiology. Four types of "Fontan Failure" were described and then published by Dr Book et al. The acknowledgment that even Dr Fontan himself realized that the Fontan procedure "imposed a gradually declining functional capacity and premature late death after an initial period of often excellent palliation." The purpose of the second "Frontiers in Fontan Failure" was to further the discussion regarding new data and technologies as well as novel interventions. The 2017 "Frontiers in Fontan Failure: Innovation and Improving Outcomes" was sponsored by Children's Healthcare of Atlanta, Sibley Heart Center Cardiology, and Emory University School of Medicine. Future directions in the management of Fontan failure include further investigations into the risk of sudden cardiac death and how to properly prevent it, achievable interventions in modifying the Fontan physiology to treat or prevent late complications, and improved and refined algorithms in Fontan surveillance. Finally, further research into the interventional treatment of lymphatic-related complications hold the promise of marked improvement in the quality of life of advanced Fontan failure patients and as such should be encouraged and contributed to.

Anesthetic Considerations for Adult Cardiac Surgery Patients with Congenital Heart Disease

The number of adults with congenital heart disease surviving into adulthood is increasing. The proportion of adults undergoing revision of a previous repair is increasing in comparison to those that present for a palliative or curative operation. At the Toronto Congenital Cardiac Centre for Adults, 528 patients underwent cardiac surgery between January 1, 1992 and December 31, 2001. The anesthetic management of the surgical correction of simple and complex congenital heart lesions includes general physiologic considerations such as dysrhythmias, hypoxemia, polycythemia, and pulmonary hypertension. Palliative shunts from early childhood have anatomical and physiologic implications for the adult. Preparation for the operating room and postoperative care are natural extensions of the anesthetic management of the surgical correction of the congenital heart lesions. Anesthetic management of septal lesions in the interventional suite and operating room is discussed. Complex lesions such as tetralogy of Fallot, transposition of the great arteries, Glenn anastomosis, and the Fontan operation are reviewed. The anesthetic management of these patients is rewarding but impossible without an integrated team approach involving cardiologists, surgeons, perfusionists, and nursing staff.

Pulmonary arteriovenous malformations after the superior cavopulmonary shunt: mechanisms and clinical implications

Children with functional single ventricle heart disease are commonly palliated down a staged clinical pathway toward a Fontan completion procedure (total cavopulmonary connection). The Fontan physiology is fraught with long-term complications associated with lower body systemic venous hypertension, eventually resulting in significant morbidity and mortality. The bidirectional Glenn shunt or superior cavopulmonary connection (SCPC) is commonly the transitional stage in single ventricle surgical management and provides excellent palliation. Some studies have demonstrated lower morbidity and mortality with the SCPC when compared with the Fontan. Unfortunately the durability of the SCPC is significantly limited by the development of pulmonary arteriovenous malformations (PAVMs) which have been commonly attributed to the absence of hepatic venous blood flow and the lack of pulsatile flow to the affected lungs. Abnormal angiogenesis has been suggested as a final common pathway to PAVM development. Understanding these fundamental mechanisms through the investigation of angiogenic pathways associated with the pathogenesis of PAVMs would help to develop medical therapies that could prevent or reverse this complication following SCPC. Such therapies could improve the longevity of the SCPC, potentially eliminate or significantly postpone the Fontan completion with its associated complications, and improve long-term survival in children with single ventricle disease.

Trends in mortality (1975-2011) after one- and two-stage Fontan surgery, including bidirectional Glenn through Fontan completion

OBJECTIVES

Techniques and strategies in the Fontan procedure have evolved over the years, including the evolution from a one- to two-stage procedure. With such adjustments made, attention should shift towards survival analysis, including bidirectional cavopulmonary shunt (BCPS) and interstage mortality. The purpose of this study was to investigate the trends in the overall mortality of all patients who underwent a BCPS or one-stage Fontan procedure at our institution in the period of 1975-2011.

METHODS

Using a single-institution, retrospective design, we reviewed the patient records of 203 patients from the University Medical Center Groningen, Netherlands, who underwent a Fontan procedure or a BCPS (with the intention to complete cavopulmonary connection at a second later stage) between 1975 and 2011. Trends in mortality were investigated by comparing survival rates during four consecutive decades (1975-84; 1985-94; 1995-2004; 2005-11), and predictors for mortality were identified.

RESULTS

During a mean follow-up of 12 years, survival was 69%. Overall mortality declined significantly during the past decades (P = 0.017). This was driven by a decrease in early mortality (P = 0.016), whereas no changes in late mortality could be demonstrated. Multivariate analyses identified a diagnosis of heterotaxy (P = 0.049) and an atriopulmonary connection type of Fontan circulation (P = 0.015) as independent risk factors for overall mortality.

CONCLUSIONS

We demonstrate that, with the inclusion of first-stage and interstage mortality also, overall survival after Fontan procedures improved over time. This improvement, however, is mainly caused by a decline in early mortality. Improvement in long-term survival of patients operated on over the past four decades could not (yet) be demonstrated in this series.

Orthotopic heart transplantation in patients with univentricular physiology

Parallel advancements in surgical technique, preoperative and postoperative care, as well as a better understanding of physiology in patients with duct-dependent pulmonary or systemic circulation and a functional single ventricle, have led to superb results in staged palliation of most complex congenital heart disease (CHD) [1]. The Fontan procedure and its technical modifications have resulted in markedly improved outcomes of patients with single ventricle anatomy [2,3,4]. The improved early survival has led to an exponential increase of the proportion of Fontan patients surviving long into adolescence and young adulthood [5]. Improved early and late survival has not yet abolished late mortality secondary to myocardial failure, therefore increasing the referrals for cardiac transplantation [6]. Interstage attrition [7] is moreover expected in staged palliation towards completion of a Fontan-type circulation, while Fontan failure represents a growing indication for heart transplantation [8]. Heart transplantation has therefore become the potential “fourth stage” [9] or a possible alternative to a high-risk Fontan operation [10] in a strategy of staged palliation for single ventricle physiology. Heart transplant barely accounts for 16% of pediatric solid organ transplants [11]. The thirteenth official pediatric heart transplantation report- 2010 [11] indicates that pediatric recipients received only 12.5% of the total reported heart transplants worldwide. Congenital heart disease is not only the most common recipient diagnosis, but also the most powerful predictor of 1-year mortality after OHT. Results of orthotopic heart transplantations (OHT) for failing single ventricle physiology are mixed. Some authors advocate excellent early and mid-term survival after OHT for failing Fontan [9], while others suggest that rescue-OHT after failing Fontan seems unwarranted [10]. Moreover, OHT outcome appears to be different according to the surgical staging towards the Fontan operation and surgical technique of Fontan completion [12].

The focus of this report is a complete review of the recent literature on OHT for failing single ventricles, outlining the clinical issues affecting Fontan failure, OHT listing and OHT outcome. These data are endorsed reporting our experience with OHT for failing single ventricle physiology in recent years.

Functional capacity following univentricular repair--midterm outcome

OBJECTIVE

Previous studies have seldom compared functional capacity in children following Fontan procedure alongside those with Glenn operation as destination therapy. We hypothesized that Fontan circulation enables better midterm submaximal exercise capacity as compared to Glenn physiology and evaluated this using the 6-minute walk test.

DESIGN AND PATIENTS

Fifty-seven children aged 5-18 years with Glenn (44) or Fontan (13) operations were evaluated with standard 6-minute walk protocols.

RESULTS

Baseline SpO(2) was significantly lower in Glenn patients younger than 10 years compared to Fontan counterparts and similar in the two groups in older children. Postexercise SpO(2) fell significantly in Glenn patients compared to the Fontan group. There was no statistically significant difference in baseline, postexercise, or postrecovery heart rates (HRs), or 6-minute walk distances in the two groups. Multiple regression analysis revealed lower resting HR, higher resting SpO(2) , and younger age at latest operation to be significant determinants of longer 6-minute walk distance. Multiple regression analysis also established that younger age at operation, higher resting SpO(2) , Fontan operation, lower resting HR, and lower postexercise HR were significant determinants of higher postexercise SpO(2) . Younger age at operation and exercise, lower resting HR and postexercise HR, higher resting SpO(2) and postexercise SpO(2) , and dominant ventricular morphology being left ventricular or indeterminate/mixed had significant association with better 6-minute work on multiple regression analysis. Lower resting HR had linear association with longer 6-minute walk distances in the Glenn patients.

CONCLUSIONS

Compared to Glenn physiology, Fontan operation did not have better submaximal exercise capacity assessed by walk distance or work on multiple regression analysis. Lower resting HR, higher resting SpO(2) , and younger age at operation were factors uniformly associated with better submaximal exercise capacity.

Bidirectional cavopulmonary shunt with additional pulmonary blood flow: a failed or successful strategy?

OBJECTIVES

In patients with single ventricle physiology, Fontan circulation is considered as the optimal surgical approach, although it entails a growing incidence of late complications. It has been speculated that the association of bidirectional cavopulmonary shunt (BCPS) and additional pulmonary blood flow (APBF) might provide long-lasting palliation. The present study was undertaken to assess the long-term outcome of this strategy.

METHODS

A group of 70 patients with single ventricle physiology, who underwent BCPS with APBF between 1990 and 2000, were reviewed retrospectively. Median age at operation was 2 years (range: 0.1-27 years). Unilateral BCPS was performed in 60 patients (86%), bilateral BCPS in 9 and the Kawashima procedure in 1. APBF was provided through antegrade pulmonary outflow tract in 43 patients (61%) and by aortopulmonary shunt in 27 (39%). Two patients died early and three were lost to follow-up. Mean follow-up of the 65 remaining patients was 13.5 ± 4 years. End-points were death, need for heart transplantation (HTx) or Fontan completion and functional outcome.

RESULTS

Five patients died (two after HTx, three from ventricular failure); overall actuarial survival was 89 ± 4% at 15 years. Six patients underwent HTx (one after Fontan completion) with two early deaths and no late mortality. Fifty-one patients underwent Fontan completion (11 with additional palliative procedures before completion); there was no early or late mortality following Fontan completion; one patient underwent HTx. Among the remaining six patients with BCPS and APBF, two were not suitable for Fontan completion and four remained suitable. Overall, clinical failure (mortality, HTx, unsuitability for Fontan completion) occurred in 13 patients (19%). Risk factors for clinical failure were older age at BCPS (P = 0.01) and postoperative complications after BCPS (P = 0.001). Considering late mortality, HTx and Fontan completion as strategic failures, the actuarial freedom from these events was 20 ± 5% at 10 years.

CONCLUSIONS

BCPS with APBF approach: (i) fails as a strategy for definitive palliation, (ii) provides a high survival rate, (iii) does not preclude a successful Fontan completion and (iv) may delay the long-term deleterious consequences of Fontan circulation. Palliation by BCPS with APBF should be achieved early in life.

Staged single-ventricle palliation in 2011: outcomes and expectations

Outcomes for staged palliation for single-ventricle heart disease have improved over the past two decades. As outcomes improve, parental expectations for survival and quality of life have risen accordingly. Nevertheless, the number of interventions and complications these patients must endure remain high. The final surgical destination of the single-ventricle patient, the total cavopulmonary connection (or Fontan operation) successfully separates systemic venous and pulmonary venous blood flow but does so at great cost. Fontan patients remain at significant risk of complications despite what are perceived to be "favorable" hemodynamics. The outcomes in this population are discussed in this review, with particular attention to the history behind our current strategies as well as to recent salient studies.

Exercise capacity reflects ventricular function in patients having the Fontan circulation

BACKGROUND

In this study we sought to determine, first, whether maximal exercise capacity reflects ventricular function, and second, whether the age of the patient, and the age of completion of the Fontan circulation, influence ventricular function and exercise performance.

METHODS AND RESULTS

Cardiac magnetic resonance imaging and cardiopulmonary exercise testing were performed in 29 patients at a median time of 6.9 years after completion of the Fontan circulation. We divided the patients into 2 groups, the first 19 having their operation below the age of 18 years, and the second group, of 10 patients, having completion of the Fontan circulation when they were older than 18 years. Parameters for ventricular function and exercise were compared for both groups with controls. Compared to controls, the younger patients had normal end-diastolic ventricular volumes, but significantly impaired ventricular function, lower maximal work load and consumption of oxygen. The older patients had greater end-diastolic ventricular volumes, and significantly poorer ventricular function than both the younger patients and the controls. Maximal work load and consumption of oxygen were significantly lower in the older patients than in the younger ones and the controls.

CONCLUSION

Patients with the Fontan circulation have an impaired systolic ventricular function, which correlates with maximal exercise capacity and uptake of oxygen. Those having completion of the Fontan circulation when younger than 18 years had significantly better ventricular function and exercise performance than those who had completion of the Fontan circulation at an older age. An early creation of the Fontan circulation may preserve cardiac function and exercise capacity.

Survival after bidirectional cavopulmonary anastomosis: Analysis of preoperative risk factors

OBJECTIVE

Prognostic factors for survival after bidirectional cavopulmonary anastomosis for functionally single ventricle are not well defined. We analyzed preoperative hemodynamic and echocardiographic data to determine risk factors for death or transplantation at least 1 year after bidirectional cavopulmonary anastomosis.

METHODS

Data for all patients who underwent bidirectional cavopulmonary anastomosis before 5 years of age at our institution from September 1995 through June 2005 were analyzed. Available preoperative echocardiograms and catheterizations were reviewed. Survivors were compared with those who died or underwent transplantation. Bivariable associations between demographic and clinical risk factors and survival status (alive without transplantation vs dead or transplanted) were assessed with Wilcoxon rank sum test and chi2 or Fisher exact tests. Survival functions were constructed with Kaplan-Meier estimates, and event times compared between subgroups with log-rank tests. Cox proportional hazard modeling was used for multivariable modeling of risk of death or transplantation.

RESULTS

One hundred sixty-seven patients underwent bidirectional cavopulmonary anastomosis with hemi-Fontan (n = 62) or bidirectional Glenn (n = 105) operations. Three patients died before discharge, 11 died later, and 1 has undergone transplantation. Freedom from death or transplantation after bidirectional cavopulmonary anastomosis was 96% at 1 year and 89% at 5 years. Multivariable analysis of preoperative variables showed atrioventricular valve regurgitation to be an independent risk factor for death or transplantation (hazard ratio 2.8, 95% confidence interval 1.1-7.1, P = .02).

CONCLUSION

Although survival after bidirectional cavopulmonary anastomosis is high, preoperative atrioventricular valve regurgitation is an important risk factor for death or transplantation.

Pulmonary artery banding before the Damus-Kaye-Stansel procedure

Subaortic stenosis (SAS) in a single ventricle leads to myocardial hypertrophy and compromises Fontan results. Moreover, controversy exists concerning the optimal surgical strategy for relieving SAS. We have applied pulmonary artery banding (PAB) before the Damus-Kaye-Stansel procedure (DKS), and here we analyze factors that influence systemic ventricular compliance. Thirteen patients underwent PAB before DKS. Median PAB duration was 5.5 months (range, 20 days to 17.7 months). Procedures administered concomitantly with DKS were Blalock-Taussig shunt (n = 6), bidirectional cavopulmonary shunt (n = 5), and Fontan operation (n = 2). All survived and were doing well after a median follow-up 2.7 years. Cardiac catheterization before DKS showed that the mean pressure gradient across the systemic ventricular outflow tract and PAB were 20.6 +/- 10.1 and 67.4 +/- 10.2 mmHg, respectively. After DKS, systemic ventricular end diastolic pressure (SVEDP) was significantly correlated with PAB duration (r = 0.65, p = 0.022), but not with PAB or systemic ventricle outflow tract pressure gradients. After DKS, SVEDP decreased or fell to within the range in patients with PAB duration less than 7 months (p < 0.05). Seven patients had a successful Fontan operation, and 6 without risk factors are waiting operation. SVEDP was found to be correlated with PAB duration, and our findings indicate that short-term PAB can be considered a safe option in patients with a single ventricle and SAS.

Single ventricle palliation: Greater risk of complications with the Fontan procedure than with the bidirectional Glenn procedure alone

BACKGROUND

This study was performed to evaluate and compare the early, intermediate, and long-term outcomes of the bidirectional Glenn procedure and Fontan procedure in patients who live at moderately high altitude.

METHODS

The outcome of each method of palliation for patients with a functionally single ventricle was retrospectively evaluated from a review of medical records.

RESULTS

The bidirectional Glenn procedure was performed in 177 patients from October 1984 to June 2004. The Fontan procedure was performed in 149 patients from June 1978 to June 2004. Cardiovascular death or heart transplantation occurred in 8% of patients after the bidirectional Glenn procedure and 17% of patients after the Fontan procedure. Complications of systemic thromboembolic events, bleeding associated with anticoagulation therapy, protein losing enteropathy, and arrhythmias requiring implantation of a pacemaker, cardioversion, or radiofrequency ablation occurred in 7% of patients after the bidirectional Glenn procedure and 47% of patients after the Fontan procedure. Cardiovascular deaths and heart transplantation occurred less frequently when the Fontan procedure was performed in patients with a previous bidirectional Glenn procedure. However, the actuarial transplant-free survival and freedom from complications was not superior for a subgroup of patients who had a Fontan procedure after a bidirectional Glenn procedure in comparison to a subgroup of patients who had a bidirectional Glenn procedure alone.

CONCLUSIONS

The bidirectional Glenn procedure can be used for long-term palliation of patients with a functionally single ventricle. Additional palliation with a Fontan procedure may increase the risk of stroke, protein losing enteropathy and arrhythmias without improving survival.

Evidence of pulmonary vascular disease after heart transplantation for Fontan circulation failure

OBJECTIVES

Elevated pulmonary vascular resistance may contribute to late Fontan circulation failure but is difficult to assess in such patients. Our aims were to assess outcomes of patients with failed Fontan circulation after heart transplantation and to determine whether elevated pulmonary vascular resistance might have contributed to the failure.

METHODS

Fifteen patients (14 Fontan circulations, 1 Kawashima circulation) underwent transplantation. The most common indication was ventricular dysfunction (mean ventricular end-diastolic pressure 12.5 mm Hg). Patients with early failures (n = 4) required transplantation less than 1 year after the Fontan operation. Those with late failures (n = 11) underwent transplantation at least 1 year after the Fontan operation. Mean age at transplantation was 11.6 years. Mean Fontan-transplantation interval was 7.4 years. Mean pulmonary arterial pressure, transpulmonary gradient, and pulmonary vascular resistance before and after transplantation were assessed. Paired t tests of variable differences were used to compare variables. Survival was estimated by the Kaplan-Meier method.

RESULTS

In-hospital mortality was 7%. There were 2 late events (1 death, 1 retransplantation) related to compliance or rejection issues. Graft survivals were 93%, 82%, and 82% at 3, 5, and 7 years, respectively. Posttransplantation pulmonary vascular resistance was elevated (>2.0 Wood units . m 2 ) in 11 of 14 survivors past initial hospitalization (mean 3.3 +/- 1.7 Wood units . m 2 ). Only patients with early Fontan failures (3 of 4) had normal posttransplantation pulmonary vascular resistance. In paired comparisons, posttransplantation transpulmonary gradient was increased by a mean of 6.8 mm Hg ( P < .0001) relative to pretransplantation value.

CONCLUSIONS

Outcomes after heart transplantation for failed Fontan circulation were good. Mild-to-moderate pulmonary vascular disease was evident after heart transplantation for late failure. Elevated pulmonary vascular resistance is a likely contributor to Fontan circulation failure.

The biological "scrabble" of pulmonary arteriovenous malformations: considerations in the setting of cavopulmonary surgery

Pulmonary arteriovenous fistulas are vascular malformations, which, by virtue of producing abnormal vascular connections proximal to the units of gas exchange, result in intrapulmonary right-to-left shunting. These malformations or fistulas reflect at least in part disordered angiogenesis, and less commonly recruitment and dilation of pre-existing vascular channels. Pulmonary arteriovenous fistulas occur in a number of diverse clinical settings. Such fistulas are a well-established feature of the Weber-Osler-Rendu complex, or hereditary haemorrhagic telangiectasia, an autosomal dominant vascular dysplasia characterized by mucocutaneous telangiectasis, epistaxis, gastrointestinal haemorrhage, and arteriovenous malformations in the lung, brain, liver and elsewhere. They are also seen in the patient with acute or chronic liver disease, disease that is usually but not invariably severe, or those with non-cirrhotic portal hypertension. They may occur as congenital malformations, single or diffuse, large or small in isolation, and when large or extensive enough may result in hypoxaemia, clinical cyanosis, and heart failure. Cerebral vascular accidents are also a well-known complication of this disorder. An extensive literature has accumulated with regard to the pulmonary arteriovenous fistulas seen in the setting of the Weber-Osler-Rendu complex, and there is considerable information on the genetics, basic biology, clinical findings, complications and therapeutic interventions of these malformations in the setting of this syndrome. These issues, however, are not the primary considerations of this review, although some aspects of this fascinating disorder will be discussed later. Rather the focus will be on pulmonary arteriovenous malformations that develop in the setting of cavopulmonary surgery, and their relationship to the pulmonary arteriovenous fistulas occurring in the hepatopulmonary syndrome. The complex tapestry of these overlapping and intersecting clinical observations will be unfolded in the light of their chronology.

Orthotopic heart transplantation for congenital heart disease: an alternative for high-risk fontan candidates?

OBJECTIVE

Evaluation of incremental risk factors for early mortality in children undergoing orthotopic heart transplantation (OHT) for congenital heart disease.

METHODS

Between 1988 and 2002, 43 patients (mean age 9.1+/-7.2 years) underwent 44 OHT for complex TGA (6), DORV (4), single ventricle (21), and other end-stage structural heart disease (11). Two discernible ventricular chambers were present in 18 pts (41.8%). Previous reconstructive or palliative procedures had been previously accomplished in 35 pts (83.3%), including atrial switch (5), systemic-to-pulmonary shunts (10), cavopulmonary anastomosis (9), Fontan completion (6), and others (5).

RESULTS

30-day survival for the 2-ventricle subgroup was 94.4+/-5.4% compared with 67.2+/-9.5% for the single ventricle subgroup (P=0.04) (overall 78.6%+/-3.3%). OHT following single ventricle staging to bi-directional cavopulmonary anastomosis exhibited 100% early survival, as opposed to 62.5+/-17.1% for OHT after systemic-to-pulmonary shunts, and 33.3+/-19.2% for OHT following failing Fontan (P=0.010). HLHS diagnosis (0.0085) and failing Fontan (P=0.003) were identified as independent predictors of early mortality by regression logistic modeling, while Fontan stage represented the only predictor of overall mortality by Cox proportional hazard. Overall 10-year survival was 54.3+/-11%.

CONCLUSIONS

OHT for structural congenital heart disease with single ventricle physiology entails substantial early mortality and bi-directional cavopulmonary anastomosis enables the best transition to heart transplant. OHT should be considered in the decision making process as an alternative to Fontan completion in high-risk candidates, since rescue-OHT after failing Fontan seems unwarranted.

[Single-stage Fontan procedure: early and late outcome in 124 patients]

INTRODUCTION AND OBJECTIVES

The Fontan procedure was designed to palliate complex congenital heart disease with univentricular physiology. A retrospective study was made to document the determinants of early (</= 30 days) and late (>/= 31 days) mortality with the modified Fontan procedure performed in one-stage over a 22-year period.

MATERIAL AND METHODS

Between 1978 and 2000, 102 atriopulmonary, 16 cavopulmonary, and 6 Kawashima type anastomoses were performed to palliate complex congenital heart defects in 124 patients with a mean age of 7.3 4.7 years. Forty-five patient and procedure-related variables were analyzed in relation to mortality. All events were verified.

RESULTS

There were 29 early (23%) and 20 late (16%) deaths. Estimated survival at 30 days, 2 years, 5 years, and 20 years was 78, 75, 66, and 50%, respectively. Subaortic stenosis, protein-losing enteropathy, and arrythmia were observed in 8, 5 and 33 patients, respectively, after surgery. Univariate and multivariable analysis indicated that left ventricular end-diastolic pressure (>/= 13 mmHg), mean pulmonary pressure (>/= 19 mmHg), mitral stenosis/atresia, atrioventricular valve regurgitation, visceral heterotaxia, absence of fenestration, risk factors criteria, duration of extracorporeal circulation, and operative technique were associated with early mortality. Reoperation, arrhythmia, and pacemaker implantation were predictors of late death. Forty percent remained free from surgical or catheter reintervention after Fontan operation at 20 years.

CONCLUSIONS

The outcome of Fontan procedure is profoundly affected by patient-related variables (ventricular function and pulmonary circulation). Postoperative arrhythmia and reoperation shortened the lifespan of the Fontan circulation model in patients with atriopulmonary connections. Total cavopulmonary anastomosis improves the physiology of univentricular circulation. In the light of our findings, the modified Fontan procedure (one or two stages) should be performed early in life to better preserve ventricular and pulmonary vascular function.

The role of the Fontan procedure in the surgical treatment of congenital heart malformations with double-outlet right ventricle

The Fontan procedure in one of its many modifications is applicable to the surgical treatment of those patients with double-outlet right ventricle who are not amenable to bi-ventricular correction. Included in this group are patients with significant hypoplasia of one of the ventricles, patients with distant (non-committed) ventricular septal defect, patients with significant straddling of the atrioventricular valves, patients with abnormal atrioventricular connections (such as absence of one of the valves), or common atrioventricular valve connection. The presence of complex associated lesions such as those seen in the heterotaxia syndromes may, by virtue of the surgical risk of attempts at bi-ventricular repair, make the Fontan approach a suitable option for these patients. The presence of a subaortic conus and the potential for subaortic obstruction, a frequent findings in patients with double outlet right ventricle, plays an important role in the preparation and conduct of the Fontan operation. Copyright 2000 by W.B. Saunders Company

Lung function and aerobic capacity in adult patients following modified Fontan procedure

OBJECTIVE

To examine cardiopulmonary performance in 52 adult patients with a Fontan circulation.

DESIGN

Retrospective cohort study. Values of maximum oxygen uptake (VO(2)max), maximum heart rate (HRmax), forced vital capacity (FVC), and forced expiratory volume in one second (FEV(1)) were compared with predictive values for different age groups. Patients were further subdivided into those with a pulmonary artery connection (RA-PA) or right atrium to right ventricle conduit (RA-RV).

RESULTS

At late follow up (median 10 years, range 1 to 26 years), patients with Fontan circulation had greatly diminished VO(2)max, HRmax, FVC, and FEV(1) compared with predicted values. Early age at surgery had a positive impact on aerobic capacity. The FEV(1):FVC ratio indicated restrictive lung function. No differences were found with respect to any variable between patients with RA-PA connections and those with RA-RV connections.

CONCLUSIONS

Patients with a Fontan circulation have greatly diminished values of aerobic capacity and a restrictive pattern of lung function. Patients with an early surgical procedure obtained higher values of VO(2)max. The theoretical benefits of including the right ventricle in a Fontan circulation were not apparent.

Surgery for congenital heart disease

General agreement has been reached on the indications for treating most congenital cardiac malformations. Strong disagreement exists, however, about timing and methods of treatment, either for congenital heart defects, for which the approach should be standardized after years of use, and even more when a new technique or a new approach is introduced to replace the existing ones. The ideal solution should be to perform prospective, randomized studies, with long-term follow-up, possibly with preliminary experimental studies to support the hypothesis. Unfortunately this is rarely possible, either because of the nonreproducibility of the malformation in an experimental environment, or because prospective, randomized studies with adequate follow-up are rarely feasible, due to the relatively small number of children with the same congenital heart defect. An updated review of the current trends in congenital heart surgery, based on the papers published in the past year, is presented here.

Definitive palliation with cavopulmonary or aortopulmonary shunts for adults with single ventricle physiology

OBJECTIVE

To compare the relative merits of cavopulmonary or aortopulmonary shunts, or both, as definitive non-Fontan palliations for patients with single ventricle physiology.

DESIGN

Clinical data, ECG, echocardiographic data, surgical records, and available postmortem material were reviewed in all patients with single ventricle physiology identified from the University of Toronto Congenital Cardiac Centre for Adults (UTCCCA) database who had not undergone a Fontan operation. Current status of patients was assessed from clinic reviews and patient contact. Two groups of patients were identified: those with cavopulmonary shunt (group 1, n = 35); and those with aortopulmonary shunt(s) only (group 2, n = 15).

RESULTS

50 adults (21 male/29 female) who underwent the last palliation at a median age of 11 years (range 1 day to 53 years) were identified. During a mean (SD) follow up of 13.0 (6.2) years at the UTCCCA, 19 patients died. Survival is 89.4% and 51.9% at 10 and 20 years, respectively, from the time patients were first seen at UTCCCA, with no differences between the groups. Most recent New York Heart Association (NYHA) classification was I-II in 21 patients, III in 25, and IV in four patients; mean haemoglobin was 190 (28) g/l, and oxygen saturation was 82 (4)%, with no group differences. Arrhythmia developed in 25 patients (atrial flutter/fibrillation in 20 and/or sustained ventricular tachycardia in 11). Atrial flutter/fibrillation was more common in patients in group 2, who also showed a greater decline in ventricular function with time. Age at last palliation, cardiothoracic ratio, and inclusion in group 2 were predictive of atrial flutter/fibrillation, poor ventricular function predictive of ventricular tachycardia, NYHA class > III, and prior ventricular tachycardia predictive of death.

CONCLUSIONS

Cavopulmonary or aortopulmonary shunts, or both, provide sustained palliation for selected patients with single ventricle physiology. Survival for both compares favourably with published Fontan series. Compared to aortopulmonary shunts, cavopulmonary shunts convey a beneficial long term effect on ventricular function. Arrhythmia is a major cause of late morbidity in these patients, relating to both ventricular dysfunction and death. Onset of sustained ventricular tachycardia is an ominous sign.