Risk factors for atrial tachyarrhythmias after the Fontan operation

OBJECTIVES

The purpose of this study was to define the incidence and risk factors for atrial tachyarrhythmias after the Fontan operation.

BACKGROUND

Atrial tachyarrhythmias cause morbidity after the Fontan operation. Causative factors may be affected by the type of systemic to pulmonary connection.

METHODS

The Fontan operation was performed in 270 consecutive patients between 1982 and 1992. The mean age at operation was 7.0 +/- 4.3 years. Direct atriopulmonary connection was used in 138 patients (51%), total cavopulmonary connection in 94 (35%) and right atrial to right ventricular connection in 38 (14%).

RESULTS

Atrial tachyarrhythmias were seen early postoperatively in 55 patients (20%), preoperative atrial tachyarrhythmia being the only risk factor. Follow-up was achieved for 228 early survivors (97%) at a mean interval of 4.4 years. There were 20 late deaths. Late atrial tachyarrhythmias were noted in 29% of patients who received an atriopulmonary connection, 14% of those who received a total cavopulmonary connection and 18% of those who received a right ventricular connection (p < 0.02). Significant risk factors as determined by univariate and multiple logistic regression analysis were atriopulmonary connection type (odds ratio 0.40 for total cavopulmonary relative to atriopulmonary connection [p < 0.05] and 0.37 for right ventricular relative to atriopulmonary connection [p = 0.08]), longer follow-up interval (odds ratio 1.32 for each consecutive year [p < 0.002]) and atrial tachyarrhythmia in the operative period (odds ratio 6.31 [p < 0.0001]).

CONCLUSIONS

Early postoperative atrial tachyarrhythmias, length of follow-up and atriopulmonary connection are significant independent risk factors for the presence of late atrial tachyarrhythmias.

The modified Fontan operation. An analysis of risk factors for early postoperative death or takedown in 702 consecutive patients from one institution

To better understand risk factors associated with early postoperative death or failure, we reviewed our entire experience with 702 consecutive patients who had the modified Fontan operation at the Mayo Clinic between October 1973 and December 1989. The event rate for takedown of repair or death during the initial hospitalization or within 30 days of the operation was 14.8% (successful takedown of the repair, n = 6; death, n = 98). To identify variables associated with early death or Fontan takedown, we analyzed 33 clinical and hemodynamic variables in a univariate and multivariate manner. On the basis of a stepwise logistic discriminant analysis, patients who were younger and operated on before 1980 with a higher preoperative pulmonary artery mean pressure, asplenia, higher intraoperative (after Fontan operation) right atrial pressure, longer aortic crossclamp time, and pulmonary artery ligation were more likely to have the outcome event of interest (p values < 0.05). A new variable, corrected pulmonary artery pressure (that is, mean preoperative pulmonary artery pressure divided by the ratio of pulmonary to systemic flow if the ratio of pulmonary to systemic flow is greater than 1.0), was significantly associated with the outcome event univariately (p = 0.002), but was no more predictive than the preoperative pulmonary artery mean pressure. Variables less predictive of the outcome event in this analysis included multiple prior operations, polysplenia syndrome, complex anatomy other than asplenia syndrome, and systemic atrioventricular valve regurgitation. These results represent the largest single-institution review of the Fontan operation and suggest that some anatomic and hemodynamic variables previously predictive of poor early outcome have been nullified by current operative methods.

Predictors of early- and late-onset supraventricular tachyarrhythmias after Fontan operation

BACKGROUND

The objectives of our study were to determine the frequency of supraventricular tachyarrhythmias (SVTAs) among modifications of the Fontan operation and identify risk factors for developing SVTA.

METHODS AND RESULTS

The population consisted of all patients who had any modification of the Fontan operation at the Mayo Clinic between 1985 and 1993. Clinically significant SVTAs were those requiring initiation or change of antiarrhythmic treatment, and they were divided into early SVTAs (<30 days after the operation) and late SVTAs (>/=30 days after the operation). Clinical histories were reviewed, and health status questionnaires were sent. Four hundred ninety-nine patients had various modifications of the Fontan operation. Frequency of early SVTA was 15%. Risk factors identified by multivariate analysis for early SVTA were AV valve regurgitation, abnormal AV valve, and preoperative SVTA. Frequency of late SVTA was 6% by 1 year, 12% by 3 years, and 17% by 5 years. Risk factors for late SVTA were age at operation (<3 or >/=10 years) and systemic AV valve replacement. By univariate and multivariate analysis, the type of Fontan operation was not a significant risk factor for late SVTA when all 6 modifications were considered. However, when we analyzed the frequency of late SVTA for the 2 recently used modifications, we found a lower frequency of late SVTA in patients with atriopulmonary connection with lateral tunnel compared with those with total cavopulmonary connection.

CONCLUSIONS

Postoperative SVTA continues to be a significant problem. Risk factors for SVTA are AV valve regurgitation, abnormal AV valve, preoperative SVTA, and age at operation. Frequency of SVTA does not appear to be related to type of Fontan procedure except for slightly lower frequency in patients with atriopulmonary connection with lateral tunnel compared with those with total cavopulmonary connection.

Fontan operation: influence of modifications on morbidity and mortality

The mortality rate of the Fontan operation for heart malformations with a single or dominant ventricle has been reduced by dividing the procedure into two stages. The hemi-Fontan procedure allows early reduction of the volume work of the single ventricle and remodeling of ventricular geometry before a completion Fontan operation. Despite the improvement of survival with this strategy (8% mortality for completion Fontan versus 16% mortality for primary Fontan operation), morbidity related to serous effusions remains substantial. Further technical modifications have been undertaken in an effort to reduce morbidity and further reduce mortality. From January 1990 through June 1993, 200 patients underwent completion Fontan procedures after previous hemi-Fontan operations. Mean age was 23 months, and 157 patients were less than 24 months of age. Diagnoses were hypoplastic left heart syndrome (127 patients), tricuspid atresia (19 patients), single left ventricle (17 patients), complex double-outlet right ventricle (16 patients), pulmonary atresia with intact ventricular septum (8 patients), and other (13 patients). Overall, early mortality rate was 8% (16 patients). In the last 112 patients, the procedure was modified technically by creating one or more fenestrations in the baffle used to separate systemic venous blood from pulmonary venous blood (36 patients), or by excluding one or more hepatic veins from the systemic venous pathway (76 patients). Early mortality for these 112 patients was reduced to 4.5% (5 patients). Substantial morbidity from serous effusions occurred at a rate of 45% (35 of 78 patients) among survivors who had received neither technical modification.(ABSTRACT TRUNCATED AT 250 WORDS)

The Fontan procedure for tricuspid atresia: early and late results of a 25-year experience with 216 patients

OBJECTIVES

We assessed the operative and late mortality and the present clinical status of 216 patients with tricuspid atresia who had a nonfenestrated Fontan procedure performed at the Mayo Clinic in the 25-year period 1973 to 1998.

BACKGROUND

The Fontan operation eliminates the systemic hypoxemia and ventricular volume overload characteristic of prior forms of palliation. However, it originally did so at the cost of systemic venous and right atrial hypertension, and the long-term effects of this "price" were unknown when the procedure was initially proposed.

METHODS

We reviewed the clinical records of the 216 patients retrospectively. These were arbitrarily grouped into early (1973 through 1980), middle (1981 through 1987) and late (1988 through 1997) surgical eras. Patient outcome was also analyzed according to age at surgery. Operative and late mortality rates were determined and present clinical status was ascertained in 167 of 171 surviving patients.

RESULTS

Overall survival was 79%. Operative mortality steadily declined and was 2% (one of 58 patients) during the most recent decade. Late survival also continues to improve. Age at operation had no effect on operative mortality, and late mortality was significantly increased only in patients who were operated on at age 18 years or older. Eighty-nine percent of surviving patients are currently in New York Heart Association class I or II.

CONCLUSIONS

The initial 25-year experience with the nonfenestrated Fontan procedure for tricuspid atresia has been gratifying, with most survivors now leading lives of good quality into adulthood. These results justify continued application of this procedure for children born with tricuspid atresia.

Conversion of modified Fontan procedure to lateral atrial tunnel cavopulmonary anastomosis

After modified Fontan procedures with atriopulmonary anastomoses or right atrium-right ventricle conduits, some patients have progressive exercise intolerance, effusions, arrhythmias, or protein-losing enteropathy. Theoretic advantages of a lateral atrial tunnel cavopulmonary anastomosis and published clinical results suggest that conversion of other Fontan procedures to the lateral atrial tunnel may afford clinical improvement for some patients. Eight patients (8 to 25 years old) with tricuspid atresia (n =4), double-inlet left ventricle (n = 3), and double-outlet right ventricle (n=1) underwent conversion to a lateral tunnel procedure between December 1990 and November 1994. An arbitrary clinical score was assigned before the lateral tunnel procedure and at follow-up. Before conversion, patients had decreased exercise tolerance (n = 8), arrhythmias (n = 6), effusions (n = 4), and protein-losing enteropathy (n = 8). At catheterization, all had a low cardiac index (1.9 +/- 0.7 L x min(-1) x M(-2), five had elevated pulmonary vascular resistance (>3 Wood units), and three had right pulmonary venous return obstruction by compression of an enlarged right atrium. Fenestrated lateral tunnel construction was undertaken 7.3 +/- 3.6 years after atriopulmonary anastomosis, with one early death related to low cardiac output. After the lateral tunnel procedure, two patients had no clinical improvement (no change in clinical score) but five patients had either marked or partial improvement. The right pulmonary vein compression present in three patients was resolved after conversion. The mean clinical scores improved from 4.5 +/- 1 to 3.0 +/- 2 (p < 0.04). In conclusion, conversion to a lateral tunnel procedure led to clinical improvement in five of eight patients at short-term follow-up and may be particularly indicated for patients with giant right atria or pulmonary vein compression who have symptoms. Pulmonary vein compression should be looked for in patients after modified Fontan procedures and can be relieved by conversion to the lateral tunnel procedure.

Cardiopulmonary function in adult patients late after Fontan repair

OBJECTIVES

The clinical status and exercise assessment of adult patients late after the Fontan operation were reviewed to determine cardiovascular function.

BACKGROUND

The Fontan operation is the final operation for many patients with tricuspid atresia or a single ventricle. Follow-up reports describe most patients to be in Canadian Cardiovascular Society functional class I or II. Objective measures of cardiac performance in the pediatric age group have shown significant dysfunction.

METHODS

Forty-seven adult patients were seen late after the Fontan operation at the Toronto Congenital Cardiac Centre for Adults. Thirty of these underwent cycle ergometry to determine maximal exercise capacity. Maximal ventilation, maximal oxygen uptake and anaerobic threshold were determined from a ramp exercise protocol. Ejection fraction at rest and during exercise was measured with gated radionuclide angiography. Results were compared with those of eight normal volunteers. Results are given as mean +/- SD.

RESULTS

Thirty patients underwent cardiopulmonary exercise testing 6.7 +/- 3.9 years after a first Fontan operation. Clinically 93% were in functional class I or II. The Fontan group patients had a significantly lower maximal work load (548 +/- 171 vs. 1,094 +/- 190 kilopond-meters, p < 0.00001), anaerobic threshold (11.2 +/- 2.9 vs. 23.6 +/- 4.6 ml/kg per min) and maximal oxygen consumption (14.8 +/- 4.5 vs. 42.1 +/- 10.0 ml/kg per min). Systemic ventricular ejection fraction was lower at rest (38 +/- 12% vs. 58 +/- 7%) and during exercise (40 +/- 15% vs. 70 +/- 8%).

CONCLUSIONS

Despite a clinical impression of good function, by objective measures adult patients continue to have significant cardiovascular limitation late after the Fontan operation.

Toward designing the optimal total cavopulmonary connection: an in vitro study

BACKGROUND

Understanding the total cavopulmonary connection (TCPC) hemodynamics may lead to improved surgical procedures which result in a more efficient modified circulation. Reduced energy loss will translate to less work for the single ventricle and although univentricular physiology is complex, this improvement could contribute to improved postoperative outcomes. Therefore to conserve energy, one surgical goal is optimization of the TCPC geometry. In line with this goal, this study investigated whether addition of caval curvature or flaring at the connection conserves energy.

METHODS

TCPC models were made varying the curvature of the caval inlet or by flaring the anastomosis. Steady flow pressure measurements were made to calculate the power loss attributed to each connection design over a range of pulmonary flow splits (70:30 to 30:70). Particle flow visualization was performed for each design and was qualitatively compared to the power losses.

RESULTS

Results indicate that curving the cavae toward one pulmonary artery is advantageous only when the flow rate from that cavae matches the flow to the pulmonary artery. Under other pulmonary flow split conditions, the losses in the curved models are significant. In contrast, fully flaring the anastomosis reduced losses over the range of pulmonary flow splits. Power losses were 56% greater for the curving as compared to flaring. Fully flaring without caval offset reduced losses 45% when compared to previous models without flaring. If flaring on all sides was implemented with caval offset, power losses reduced 68% compared to the same nonflared model.

CONCLUSIONS

The results indicate that preferentially curving the cavae is only optimal under specific pulmonary flow conditions and may not be efficient in all clinical cases. Flaring of the anastomosis has great potential to conserve energy and should be considered in future TCPC procedures.

Lateral tunnel versus extracardiac conduit fontan procedure: a concurrent comparison

BACKGROUND

The aim of this study was to compare the outcomes of the lateral tunnel (LT) and extracardiac conduit (ECC) Fontan procedures at a single institution over the same time period.

METHODS

From November 1995 through October 2002, 70 Fontan procedures were performed: 37 LT and 33 ECC. All were fenestrated; 96% were staged with a prior superior cavopulmonary connection. Compared with the ECC patients, the LT patients were younger (2.7 +/- 1.1 vs 3.9 +/- 2.5 years; p = 0.01), had a higher incidence of hypoplastic left heart syndrome (57% vs 21%; p < 0.01), and a longer aortic cross-clamp time (55 +/- 13 vs 26 +/- 15 min; p < 0.01). Weight, gender, preoperative cardiac catheterization values, and cardiopulmonary bypass time did not differ between the two groups.

RESULTS

Operative mortality was 2.8%, 1 patient in each group (p = 1.0). Over the first 24 hours following operation the mean Fontan pressure, transpulmonary gradient, and common atrial pressure did not differ between LT and ECC patients. The median duration of mechanical ventilation (LT 12 vs ECC 18 hours), intensive care unit stay (LT 2 vs ECC 3 days), chest tube drainage (LT 10 vs ECC 8 days), and hospital stay (LT 11 vs ECC 12 days) did not differ. The ECC patients had a higher incidence of sinus node dysfunction both in the postoperative period (27% vs LT 8%; p = 0.09), and persisting at hospital discharge (10% vs LT 0%; p = 0.02). Mean follow-up was 3.6 +/- 1.6 years in LT, and 3.0 +/- 2.2 years in ECC patients (p = 0.2). There was one late death. Actuarial survival at 5 years is 97% for LT, and 91% for ECC patients (p = 0.4); 96% of patients are in NYHA class I, and 4% in class II, with no difference between groups. Sinus node dysfunction was seen during follow-up in 15% LT vs 28% ECC patients (p = 0.2).

CONCLUSIONS

The LT and ECC approaches had comparable early and mid-term outcomes, including operative morbidity and mortality, postoperative hemodynamics, resource use, and mid-term survival and functional status. ECC patients had a higher incidence of sinus node dysfunction early after operation.

Univentricular repair: is routine fenestration justified?

BACKGROUND

A decade after the introduction of baffle fenestration, the outcome of Fontan-type repair for hearts with a functional single ventricle finally looks promising. Our study was designed to assess the impact of fenestration on the outcome of univentricular repairs.

METHODS

From January 1988 to December 1997, 348 patients (104 with tricuspid atresia and 244 with other morphological diagnoses) underwent univentricular repair at our institute. Since 1994, routine fenestration of the atrial baffle was performed in all patients (n = 126).

RESULTS

The overall Fontan failure rate was 14% (50 of 348) and included 45 early deaths and five Fontan take downs. Absence of fenestration was the only and highly significant predictor of Fontan failure (risk ratio [RR] 3.3, 95% confidence interval [CI] 1.49 to 7.31, p = 0.002). Significant pleural effusion was seen in 27% of patients. Absence of fenestration of the atrial baffle (RR 3.97, 95% CI 2.17 to 7.26, p < 0.001) and aortic cross-clamp time more than 60 minutes (RR 2.15, 95% CI 1.3 to 3.5, p = 0.002) were found to be significant risk factors. The follow-up ranged from 6 to 120 months (mean 46.0 +/- 18.0 months). There were 12 late deaths and 5 patients were lost to follow-up. Actuarial survival (Kaplan Meier) at 90 months was 81% +/- 4%. Two hundred and fifty-eight patients (90%) were in New York Heart Association class I at their last follow-up visit. Oxygen saturation in the fenestrated group ranged from 85% to 94% (mean 89%). Thirty patients (26%) had spontaneous closure of the fenestration over a mean period of 34 months, and there has been no incidence of late systemic thromboembolism. In no instance has there been a need to close the fenestration.

CONCLUSIONS

Elective fenestration of the intraatrial baffle is associated with decreased Fontan failure rate and decreased occurrence of significant postoperative pleural effusions. Routine elective fenestration of the atrial baffle may, therefore, be justified in all univentricular repairs.

Impact of early ventricular unloading on exercise performance in preadolescents with single ventricle Fontan physiology

OBJECTIVES

We sought to determine if early ventricular volume unloading improves aerobic capacity in patients with single ventricle Fontan physiology.

BACKGROUND

Surgical strategies for patients with single ventricle include intermediate staging or early Fontan completion to reduce the adverse affects of prolonged ventricular volume load. The impact of this strategy on exercise performance has not been evaluated.

METHODS

Retrospectively, we reviewed the exercise stress test results of all preadolescents with single ventricle Fontan physiology. "Volume unloading" was considered to have occurred at the time of bidirectional cavopulmonary anastomosis or at the time of Fontan surgery in those patients who did not undergo intermediate staging. Potential predictors of aerobic capacity were analyzed using multivariate regression.

RESULTS

The patients (n = 46) achieved a mean percentage predicted of maximal oxygen consumption (VO2max) of 76.1% +/- 21.1%. The mean age at the time of volume unloading was 2.7 +/- 2.4 years, and the mean age at testing was 8.7 +/- 2 years. Intermediate staging was performed in 16 of 46 patients (35%). In multivariate analysis, younger age at volume unloading was associated with increased aerobic capacity (p = 0.003). Other variables were not predictive. The subgroup of patients who underwent volume unloading before two years of age achieved a mean percentage predicted VO2max of 88.6% +/- 24.1%.

CONCLUSIONS

Preadolescents with single ventricle who undergo volume unloading surgery at an early age demonstrate superior aerobic capacity compared with those whose surgery is delayed until a later age.

Outcomes after bidirectional cavopulmonary shunt in infants less than 6 months old

OBJECTIVES

We sought to assess the results after bidirectional cavopulmonary shunt (BCPS) in infants < 6 months old and to identify risk factors for poor outcome.

BACKGROUND

Although BCPS is a well established procedure for the palliation of patients with a single-ventricle heart, there have been very few reports of outcomes after BCPS in young infants.

METHODS

Since 1990, 42 infants between 0.8 and 6.0 months of age (mean [+/-SD] 3.7 +/- 1.4) have undergone BCPS for primary (n = 16) or secondary (n = 26) palliation of tricuspid atresia (n = 13), hypoplastic left heart syndrome (n = 10) or other forms of functional single-ventricle heart (n = 19). Accessory pulmonary blood flow was included in 18 patients. Preoperative and perioperative data were gathered on retrospective review of patient records, and follow-up was conducted by means of direct physician contact or record review.

RESULTS

The overall hospital mortality rate, including that associated with reoperations, was 4.8% (2 of 42 patients). Seven patients (17%) required reoperation related to the BCPS or pulmonary blood flow in the early postoperative period: Procedures included take-down of the BCPS in four patients, with one early death, and procedures to decrease pulmonary blood flow in three patients. Age < 1 month correlated significantly with early death and with early failure of the BCPS (death or take-down). Follow-up of the 37 patients discharged with intact BCPS was obtained at a mean +/-SD of 14.3 +/- 11.3 months postoperatively, during which time three patients died (at 6.5 +/- 2.5 months). The 2-year actuarial survival rate for patients undergoing BCPS at < 6 months of age was 86%. Overall freedom from death or take-down (including early and late events) was significantly lower in patients < 2 months old than in those > 2 months old. Four patients have undergone successful Fontan completion (18.3 +/- 2.9 months postoperatively), and one patient whose BCPS was taken down subsequently underwent successful restoration of a BCPS.

CONCLUSIONS

Outcomes after BCPS in young infants are comparable to those in older infants and children. However, our current preference is to defer this procedure until after 2 months of age.

The modified Fontan procedure: early and late results in 132 adult patients

OBJECTIVE

The modified Fontan procedure, usually performed in children, is used for the treatment of anomalies with a single functional ventricle. We reviewed our experience with the modified Fontan procedure performed in the adult patient.

METHODS

Between October 1973 and May 2001, the modified Fontan procedure was performed on 132 adult patients (74 men, 58 women). Median age was 23 years (range, 18 to 53 years). Diagnoses included tricuspid atresia in 34 patients (26%), double-inlet left ventricle in 48 (36%), and complex lesions in 50 (38%). The majority of patients (89%) had at least one prior palliative procedure; the most common procedures were Blalock-Taussig shunt in 85 patients and Glenn anastomosis in 31.

RESULTS

Operations included an atriopulmonary connection in 74 patients, lateral tunnel in 27, intra-atrial conduit in 14, right atrium-to-right ventricle in 9, extra-cardiac conduit in 3, and other in 5. Overall early mortality was 8.3%. Mortality was 6.5% for operations performed after 1980. This is comparable to the mortality of the modified Fontan procedure performed in children during the same time interval at our institution. All 7 of the early deaths since 1980 occurred in the complex lesion group. Morbidity included prolonged pleural effusion in 36 patients, atrial arrhythmias in 25, reoperation for bleeding in 13, permanent pacemaker in 8, and stroke in 2. Mean follow-up was 9.1 years with a maximum of 21.2 years. Actuarial survival for early survivors was 89% (84,95), 75% (67,84), and 68% (58,79) at 5, 10, and 15 years, respectively. Freedom from late reoperation was 89% (83,95), 85% (78,93), and 80% (70,91) at 5, 10 and 15 years, respectively. The majority (90%) of present survivors were New York Heart Association class I or II at follow-up.

CONCLUSIONS

In properly selected adult patients with functional single ventricle, the modified Fontan procedure can be performed with early mortality similar to younger patients. Early mortality is more likely with complex lesions. The majority of late survivors have a good quality of life.

Skeletal muscle hemodynamics and endothelial function in patients after Fontan operation

To elucidate the relation between exercise capacity and peripheral hemodynamics in patients after the Fontan operation, near-infrared spectroscopy was performed on the vastus lateralis muscle, and flow-mediated vasodilation of the brachial and posterior tibial arteries was done with high-resolution ultrasonography. In Fontan patients, diminished exercise capacity was related to a reduced blood flow supply and an attenuated post-exercise oxygen resaturation of the working skeletal muscle, which also was related to impaired endothelium-dependent vasodilation.

The failing Fontan circulation: successful conversion of atriopulmonary connections

OBJECTIVES

Symptoms from low cardiac output or refractory atrial arrhythmias are complicating atriopulmonary (classical) Fontan connections. We present our experience of converting such patients to total cavopulmonary connections with and without arrhythmia surgery.

METHODS

Between 1997 and 2002, 15 patients (mean age, 19.7 +/- 7.0 years) underwent conversion operations 12.7 +/- 3.5 years after atriopulmonary Fontan operations. Preoperative New York Heart Association functional class was I in 2 patients, II in 2 patients, III in 6 patients, and IV in 5 patients. Four patients underwent intracardiac lateral tunnel conversion alone, and 11 received extracardiac total cavopulmonary connection, right atrial reduction, and cryoablation.

RESULTS

No mortality occurred. One patient had conduit obstruction in the immediate postoperative period requiring replacement, and another required a redo operation for endocarditis. Average hospitalization was 17.9 +/- 9.38 days; chest drains were removed on median day 4 (range, 1-29; mean, 7.4 +/- 7.58 days). At follow-up (mean, 42.6 +/- 22.1 months), late atrial arrhythmias had recurred in 3 of 4 patients with intracardiac total cavopulmonary connections (without ablation) and 1 of 11 patients with extracardiac total cavopulmonary connections with ablation. All patients are in New York Heart Association class I or II. Exercise ability (Bruce protocol) improved 69% from a mean of 6.18 +/- 4.01 minutes to 10.45 +/- 2.11 minutes (P <.05). Need for antiarrhythmic agents decreased postoperatively (patients receiving < or =1 antiarrhythmic: 9 preoperatively vs 15 at long-term follow-up, P <.05). No patient has required transplantation. Protein-losing enteropathy, which was present in 1 patient, improved transiently with conversion. There was 1 late death from gastrointestinal hemorrhage.

CONCLUSIONS

Fontan conversion can be achieved with low mortality and improvement in New York Heart Association class and exercise ability. Concomitant arrhythmia surgery reduces the incidence of late arrhythmias.

Mechano-Electrical Interaction Late After Fontan Operation

Background— The growing population with Fontan operation surviving into adulthood has significant morbidity and mortality rates from recurrent atrial tachyarrhythmias. We hypothesized that the structural characteristics and electrical behavior of atria may differ in these patients compared with those without arrhythmias.

Methods and Results— We studied 33 consecutive patients (age, 25.4±9.5 years) with Fontan circulation, of whom 19 had a history of documented sustained atrial tachyarrhythmias. We analyzed their clinical and investigational data, including echocardiographic assessment of atrial dimensions and surface 12-lead ECG measurement of the P-wave duration and its dispersion between leads. Twenty age- and sex-matched healthy control subjects were also studied. First, patients who had the Fontan procedure overall had longer P-wave duration (144±33 versus 100±7 ms, P <0.001) and greater P-wave dispersion (74±33 versus 34±9 ms, P <0.001) than control subjects. Among the patients who had the Fontan procedure, those with atrial tachyarrhythmias had longer P-wave duration (159±28 versus 123±28 ms, P <0.001) and greater P-wave dispersion (91±30 versus 50±19 ms, P <0.001) than those without. Second, the patients with atrial tachyarrhythmias who had the Fontan procedure had larger right atrial dimension than those without arrhythmias (6.4±1.4 versus 5.0±1.0 cm, P =0.01). Third, both P-wave duration and dispersion were significantly correlated to right atrial dimension within the Fontan group ( r =0.55, P =0.002, and r =0.56, P =0.002, respectively).

Conclusions— Patients with atrial tachyarrhythmias late after Fontan operation have longer P-wave duration and P-wave dispersion and larger right atrial dimension than those without the arrhythmias; these abnormalities are interrelated. This observation represents an atrial mechano-electrical remodeling phenomenon in parallel to an increase in arrhythmia propensity in this vulnerable population and warrants further investigation.

Fenestration of the Fontan circuit as treatment for plastic bronchitis

Plastic bronchitis is a rare, potentially life-threatening condition in which protein casts form within and occlude the bronchus, resulting in pulmonary failure, and has been identified as a complication after the Fontan procedure. We present a case of a 5-year-old girl who had undergone an extracardiac fenestrated Fontan repair as a component of staged palliation for tricuspid atresia. Six weeks following surgery, the patient presented with airway obstruction, coughing a bronchial cast. Medical therapies to optimize heart function and attempt to control cast formation were implemented, with little clinical impact. Following cardiac catheterization to stent open the fenestration, the symptoms of plastic bronchitis resolved. Cast expectoration recurred following spontaneous closure of the stented fenestration and again resolved with recreation of the baffle defect. Fenestration of the Fontan circuit alters hemodynamics, thereby providing an additional therapeutic option for this devastating disorder.

Conversion of atriopulmonary or lateral atrial tunnel cavopulmonary anastomosis to extracardiac conduit Fontan modification

OBJECTIVE

Obstruction of the atriopulmonary anastomosis or the lateral atrial tunnel cavopulmonary anastomosis in the Fontan circulation for univentricular physiology may result in dilation of the right atrium or the right atrial free wall that is incorporated in the lateral atrial tunnel, respectively. Secondary detrimental sequelae may consist of supraventricular dysrhythmias, thromboembolism, right pulmonary vein compression, pleural effusions, and protein-losing enteropathy. Conversion of these Fontan connections to an extracardiac conduit cavopulmonary anastomosis may improve central systemic venous flow patterns and provide clinical improvement in these patients.

METHODS

Eighteen patients (7-40 years old) with atriopulmonary anastomosis (n = 15) or obstructed lateral atrial tunnel cavopulmonary anastomosis (n = 3) presented at 5.7 +/- 3.9 years with moderate to severe right atrial dilation (n = 15), Fontan pathway obstruction (n = 12), atrial dysrhythmia (n = 13), pleural effusion (n = 8), right atrial thrombus (n = 3), right pulmonary vein compression (n = 3), and protein-losing enteropathy (n = 3). All patients underwent conversion to an extracardiac conduit cavopulmonary anastomosis.

RESULTS

Two of the three patients with protein-losing enteropathy died (2/18; 11%) on the 30th and 52nd postoperative days. At a mean follow-up of 19 months, the remaining 16 patients had marked (n = 11) or moderate (n = 5) clinical improvement. The SaO2 improved from 90.7 +/- 5.3% to 96.0 +/- 4.1%. None of the patients had obstruction in the systemic venous pathway. In the 13 surviving patients with previous atriopulmonary anastomosis there was a drastic reduction in right atrial size. Four of 13 patients with atrial dysrhythmias converted to sinus rhythm. The right pulmonary vein compression as present in three patients resolved after conversion. Pleural effusions disappeared in four patients.

CONCLUSIONS

Conversion to an extracardiac cavopulmonary connection may lead to clinical improvement in patients with atriopulmonary or lateral atrial tunnel Fontan connection associated with specific target conditions such as obstruction, pulmonary vein compression, right atrial enlargement, atrial dysrhythmia, or atrial thrombus. The conversion operation should not be unduly delayed to prevent irreversible deterioration of clinical status with chronic rhythm disturbances or protein-losing enteropathy. The benefit of the conversion operation is questionable in patients with poor clinical condition and protein-losing enteropathy.

Total cavopulmonary connection with an extracardiac conduit: experience with 100 patients

BACKGROUND

In the Fontan procedures total cavopulmonary connection with an extracardiac conduit is a concern. The potential benefits of an extracardiac conduit may be the avoidance of postoperative supraventricular arrhythmias over the long-term, hemodynamic benefits due to laminar flow, possibility of completion without anoxic arrest, and applicability to anomalous systemic or pulmonary venous return, or both anomalous systemic and pulmonary venous return. We demonstrate early to midterm results of total cavopulmonary connection with an extracardiac conduit.

METHODS

Between March 1994 and February 2000, a total of 100 patients underwent total cavopulmonary connection with an extracardiac conduit. In 27 patients, who underwent a single stage total cavopulmonary connection operation, 7 were done without palliation. Seventy-three patients had undergone a bidirectional Glenn shunt before completion of the total cavopulmonary connection. We used an expanded polytetrafluoroethylene tube graft as the extracardiac conduit.

RESULTS

Cardiopulmonary bypass time was 133.2+/-55.2 minutes. Myocardial ischemic time was 38.5+/-23.2 minutes in 40 patients who needed cardioplegic cardiac arrest for intracardiac procedures. Intraoperative fenestration was done in only 1 patient. There were no operative deaths. During follow-up of 37.3 months, there were 5 late deaths. When compared with the patients treated by the lateral tunnel technique in our institute, there was no significant difference in actuarial survival rate, but the event free rate of the extracardiac conduit group was significantly superior to the lateral tunnel group.

CONCLUSIONS

Total cavopulmonary connection with the extracardiac conduit produced good results in short to midterm follow-up.

Quantitative assessment of systolic and diastolic ventricular function with tissue Doppler imaging after Fontan type of operation

BACKGROUND

There is evidence that "inappropriate hypertrophy" of the single left ventricle, which occurs as a result of acute preload reduction, leads to adverse consequences on ventricular function. However, a systematic study of the capability of tissue Doppler imaging (TDI) to assess systolic and diastolic ventricular functions after the Fontan procedure is still missing.

METHODS

Twenty-four postoperative patients aged 12-33 years were prospectively evaluated with two-dimensional echocardiography equipped with TDI capabilities. Nineteen age-matched normal subjects were selected as controls. Good-quality echoes for the measurement of ejection fractions were available in 21 patients. Ten patients (group 1) had systolic dysfunction (ejection fraction < 50%), and 11 patients (group 2) had normal systolic function. Peak systolic and diastolic wall velocities were acquired from the two-chamber view in the myocardia and mitral annulus.

RESULTS

Compared with controls, the Fontan patients had a significantly reduced peak systolic velocity at wall and annulus sites. A linear correlation existed between ejection fraction and systolic myocardial velocity from the annular sites. Group 1 patients had lower wall velocities and lower annulus velocities both in systole and diastole. Group 2 patients had preserved systolic velocities but decreased regional and annular early diastolic velocities, suggesting impaired filling. Multiple correlation analysis showed a relation between peak early diastolic mitral velocity and ventricular ejection fraction, mean mitral annular motion at systole, mass/volume ratio, and the number of years post Fontan revision.

CONCLUSIONS

Myocardial velocities recorded after the Fontan operation give insight into systolic and diastolic ventricular functions. The peak systolic mitral annular velocity correlated well with the ventricular ejection fraction. The peak early diastolic velocity and the ratio between the early and late diastolic mitral annular velocity are reduced and reflect diastolic dysfunction even in the presence of normal systolic ejection fraction.

Extracardiac conduit fontan procedure: early and intermediate results

OBJECTIVE

The extracardiac Fontan procedure, as compared with classic atriopulmonary connections, may have the potential for optimizing ventricular and pulmonary vascular function by maximizing the laminar flow principle, by the avoidance of intra-atrial suture lines and cardiac manipulation, and by minimizing cardiopulmonary bypass time. In this study the clinical results of this procedure are assessed.

METHODS

From January 1990 until January 1997, 45 patients (33 males and 12 females) with a median age of 4.0 years (range 2.7-38 years) underwent an extracardiac Fontan procedure for univentricular physiology. The underlying diagnoses included tricuspid atresia (n=19), double-inlet left ventricle (n=11), and complex anomalies (n=15). Forty patients (89%) were in sinus rhythm. The median ventricular ejection fraction was 60%. In 37 patients (82%) the procedure was staged.

RESULTS

Median cardiopulmonary bypass time was 72 min, with a decrease to a median time of 24 min in the last ten patients. Aortic cross-clamping was avoided in 33 patients (73%). The intraoperative Fontan pressure and transpulmonary gradient were low: 13.6+/-3.2 and 8.5+/-3.9 mmHg, respectively. Transient supraventricular tachyarrhythmias were observed in six patients (13%). There was no early or late mortality. At a median follow-up of 64 months (range 26-105 months), 39 patients (87%) were in NYHA class I, four (9%) were in NYHA class II, and two (4%) were in class III. Forty patients (89%) remained in sinus rhythm. The median ventricular ejection fraction was 59%. The median arterial oxygen saturation raised from 82% preoperatively to 97%. Functional class (P=0.02), maintenance of sinus rhythm (P=0.04), and preservation of ventricular function (P=0.05) was superior in patients who were appropriately staged. None of the patients had atrial thrombus, chronic pleural effusions, or protein losing enteropathy.

CONCLUSIONS

In the majority of patients, the extracardiac Fontan procedure, when performed as a staged procedure, provides excellent early and midterm results in terms of quality of life, maintenance of sinus rhythm, and preservation of ventricular function.

Relation of Magnetic Resonance Elastography to Fontan Failure and Portal Hypertension

Fontan associated liver disease is associated with morbidity and mortality in palliated single-ventricle congenital heart disease patients. Magnetic resonance elastography (MRE) provides a quantitative assessment of liver stiffness in Fontan patients. We hypothesized that MRE liver stiffness correlates with liver enzymes, hemodynamics, portal hypertension, and Fontan failure (FF). All adult Fontan patients who had MRE between 2011 and 2018 were included. Radiologic portal hypertension was defined as splenomegaly, ascites, and/or varices. FF was defined as death, transplantation, or heart failure symptoms requiring escalation of diuretics. Seventy patients with a median age of 24.7 years and a median follow-up from MRE of 3.9 years were included. The median liver stiffness was 4.3 kPa (interquartile range [IQR]: 3.8 to 5.0 kPa). There was a weak, positive correlation between liver stiffness and Fontan pathway pressure (r = 0.34, p = 0.03). There was a moderate negative correlation of liver stiffness with ventricular ejection fraction (r = -0.52, p = 0.03). Liver stiffness was weakly positively correlated with liver transaminases and gamma glutamyl transferase. Patients with portal hypertension had higher liver stiffness compared to patients without (5.2 ± 1.3 vs 4.2 ± 0.8 kPa, p = 0.03). At MRE or during follow-up, 13 patients (19%) met definition of FF and had significantly higher liver stiffness compared to patients without FF (5.1 [IQR: 4.3 to 6.3] vs 4.2 [IQR: 3.7 to 4.7] kPa, p = 0.01). Liver stiffness above 4.5 kPa differentiated FF with a sensitivity of 77% and specificity of 77%. In conclusion, elevated MRE-derived liver stiffness is associated with worse hemodynamics, liver enzymes and clinical outcomes in Fontan patients. This measure may serve as a global imaging biomarker of Fontan health.

Protein-losing enteropathy after Fontan operation: resolution after baffle fenestration

A 4-year-old child with hypoplastic left heart syndrome and a 6-year-old child with tricuspid atresia had both undergone staged reconstructive operations culminating in a Fontan operation. Peripheral edema, ascites, and hypoalbuminemia refractory to dietary manipulation and steroid therapy developed in both patients. After hemodynamic assessment, each child underwent surgical creation of a 4.8-mm fenestration in the previously placed baffle that separated the systemic venous pathway from the pulmonary venous atrium. Peripheral edema and ascites promptly resolved and serum protein levels normalized within 2 weeks after operation. Systemic arterial saturation is 86% in each child, and both children remain clinically well with no evidence of protein-losing enteropathy on normal diets and without specific medical therapy.

Modified Norwood operation for single left ventricle and ventriculoarterial discordance: an improved surgical technique

BACKGROUND

Patients with univentricular hearts and ventriculoarterial discordance with potentially obstructed systemic blood flow continue to pose difficult management problems. The goals of neonatal palliative operations are to control pulmonary blood flow while avoiding pulmonary artery distortion, to relieve systemic outflow tract obstruction, and to avoid heart block.

METHODS

Between January 1987 and December 1996, 38 patients with either tricuspid atresia or a double-inlet left ventricle and ventriculoarterial discordance underwent a modified Norwood procedure. Their mean age was 15 days, and their mean weight was 3.4 kg. Aortic arch anomalies were present in 92% of the patients. Morbidity and mortality statistics, intraoperative data, and postoperative echocardiograms were reviewed.

RESULTS

There were 3 early deaths (7.8%) and 5 late deaths (13.1%). The actuarial survival rates at 1 month, 1 year, and 5 years were 89%, 82%, and 71%, respectively. Follow-up was complete in all children at a mean interval of 30 +/- 9 months. None of the patients had significant neoaortic valve insufficiency, and 1 patient required therapy for residual aortic arch obstruction. Nine patients (30% of the survivors) have undergone the hemi-Fontan procedure, and 18 patients (60%) successfully have undergone the Fontan procedure.

CONCLUSIONS

In this patient population, we recommend the modified Norwood procedure as the neonatal palliative treatment of choice. It can be performed with acceptable early morbidity and mortality, and it improves suitability for the Fontan procedure. It reliably relieves all levels of systemic outflow tract obstruction, controls pulmonary blood flow, and avoids heart block.