The short- and mid-term results of bidirectional cavopulmonary shunt with additional source of pulmonary blood flow as definitive palliation for the functional single ventricular heart

The impact of additional antegrade pulmonary blood flow at bidirectional Glenn shunt on long-term outcomes

OBJECTIVES

We investigated the impact of additional antegrade pulmonary blood flow on the long-term outcomes after bidirectional Glenn shunt.

METHODS

From 2001 to 2015, 279 patients underwent bidirectional Glenn shunt as an interim palliation for a functionally single ventricle. After excluding patients with a previous Kawashima or Norwood operation, 202 patients with preexisting antegrade pulmonary blood flow before bidirectional Glenn shunt were included in this study. Antegrade pulmonary blood flow was eliminated in 110 patients (no antegrade pulmonary blood flow group) and maintained in 92 patients (antegrade pulmonary blood flow group). The impact of antegrade pulmonary blood flow at bidirectional Glenn shunt on long-term outcome was analyzed using inverse probability of treatment weighting.

RESULTS

Median age and body weight at bidirectional Glenn shunt were 8 months and 7.8 kg, respectively. Prolonged chest tube drainage or readmission for effusion after bidirectional Glenn shunt was more frequent in the antegrade pulmonary blood flow group (odds ratio, 3.067; 95% confidence interval, 1.036-9.073; P = .043). In the no antegrade pulmonary blood flow group, B-type natriuretic peptide level was decreased further until the Fontan operation (P = .012). In the no antegrade pulmonary blood flow group, oxygen saturation was lower just after bidirectional Glenn shunt, although it was increased further until Fontan operation (P < .001), despite still lower oxygen saturation before Fontan operation compared with antegrade pulmonary blood flow group (P < .001). The McGoon ratio was decreased in both groups without intergroup difference, although the McGoon ratio before Fontan operation was higher in the antegrade pulmonary blood flow group (2.3 ± 0.4 vs 2.1 ± 0.4, P = .008). Overall transplant-free survival was worse in the antegrade pulmonary blood flow group (hazard ratio, 2.37; confidence interval, 1.089-5.152; P = .030).

CONCLUSIONS

Maintaining antegrade pulmonary blood flow at bidirectional Glenn shunt was beneficial for higher oxygen saturation and larger pulmonary artery size before Fontan operation. However, it was unfavorable for overall transplant-free survival with a sustained higher risk of death or transplant until the elimination of antegrade pulmonary blood flow.

Superior Cavopulmonary Connection: Its Physiology, Limitations, and Anesthetic Implications

The superior cavopulmonary connection (SCPC) or "bidirectional Glenn" is an integral, intermediate stage in palliation of single ventricle patients to the Fontan procedure. The procedure, normally performed at 3 to 6 months of life, increases effective pulmonary blood flow and reduces the ventricular volume load in patients with single ventricle (parallel circulation) physiology. While the SCPC, with or without additional sources of pulmonary blood flow, cannot be considered a long-term palliation strategy, there are a subset of patients who require SCPC palliation for a longer interval than the typical patient. In this article, we will review the physiology of SCPC, the consequences of prolonged SCPC palliation, and modes of failure. We will also discuss strategies to augment pulmonary blood flow in the presence of an SCPC. The anesthetic considerations in SCPC patients will also be discussed, as these patients may present for noncardiac surgery from infancy to adulthood.

Palliative Operations for Cyanotic Congenital Heart Disease with Severely Asymmetrical Pulmonary Arteries

BACKGROUND

Surgically managing patients with complex congenital heart disease and severely asymmetrical pulmonary arteries is challenging. Here, we report our experience using combined palliative procedures.

METHOD

The medical records of 28 patients with complex congenital heart disease and severely asymmetrical pulmonary arteries who underwent combined palliative procedures between January 2004 and April 2013 were retrospectively reviewed until January 2018. The patients were divided into three groups according to shunt procedure timing: in group A (n = 15), cavopulmonary and systemic-pulmonary shunting were performed simultaneously; in group B (n = 11), systemic-pulmonary shunting was performed first; and in group C (n = 2), cavopulmonary shunt was performed first. Patients were followed for a mean ± standard deviation of 4.18 ± 2.22 years.

RESULTS

No operative deaths occurred. There were no postoperative complications in groups B or C, but there was one case of pulmonary effusion and one of chylothorax in group A. The superior vena cava pressures were higher in patients in groups A and B than in those in group C. The ventilatory support duration and intensive care unit stays were longer in group A than in groups B and C (p < 0.01). Hypoplastic pulmonary artery development significantly improved after the use of three systemic-pulmonary shunts (p < 0.05), while the peripheral oxygen saturation increased from 67%±17% preoperatively to 85%±8% postoperatively (p < 0.001). Haemoglobin concentration decreased from 190 ± 34 g/L preoperatively to 136 ± 26 g/L postoperatively (p < 0.001). Two patients underwent double ventricle correction. Two patients underwent Fontan procedure. One patient underwent one and a half ventricle correction. One patient underwent collateral occlusion.

CONCLUSIONS

Combined palliative procedures can achieve acceptable arterial oxygen saturation without extra volume loading and rescue the hypoplastic pulmonary artery.

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.

Numerical Investigation of the Effect of Additional Pulmonary Blood Flow on Patient-Specific Bilateral Bidirectional Glenn Hemodynamics

The effect of additional pulmonary blood flow (APBF) on the hemodynamics of bilateral bidirectional Glenn (BBDG) connection was marginally discussed in previous studies. This study assessed this effect using patient-specific numerical simulation. A 15-year-old female patient who underwent BBDG was enrolled in this study. Patient-specific anatomy, flow waveforms, and pressure tracings were obtained using computed tomography, Doppler ultrasound technology, and catheterization, respectively. Computational fluid dynamic simulations were performed to assess flow field and derived hemodynamic metrics of the BBDG connection with various APBF. APBF showed noticeable effects on the hemodynamics of the BBDG connection. It suppressed flow mixing in the connection, which resulted in a more antegrade flow structure. Also, as the APBF rate increases, both power loss and reflux in superior venae cavae (SVCs) monotonically increases while the flow ratio of the right to the left pulmonary artery (RPA/LPA) monotonically decreases. However, a non-monotonic relationship was observed between the APBF rate and indexed power loss. A high APBF rate may result in a good flow ratio of RPA/LPA but with the side effect of bad power loss and remarkable reflux in SVCs, and vice versa. A moderate APBF rate could be favourable because it leads to an optimal indexed power loss and achieves the acceptable flow ratio of RPA/LPA without causing severe power loss and reflux in SVCs. These findings suggest that patient-specific numerical simulation should be used to assist clinicians in determining an appropriate APBF rate based on desired outcomes on a patient-specific basis.

Exercise performance after univentricular palliation

Background:

The optimal timing, need for primary/staged procedure in patients undergoing univentricular palliation, is debatable.

Aims:

We performed this study to assess the exercise performance of patients undergoing various forms of univentricular palliation.

Setting and Design:

This was a retrospective, prospective comparative study conducted at a multispecialty tertiary referral center.

Patients and Methods:

Between January 2012 and June 2015, 117 patients undergoing either bidirectional Glenn (BDG) (n = 43) or Fontan (total cavopulmonary connection [TCPC]) (n = 74) underwent exercise testing.

Statistical Analysis:

Comparisons between subgroups for continuous data were made with Student's t-test if normally distributed and Wilcoxon rank-sum test otherwise. Tests between subgroups for qualitative data were made with Pearson's Chi-square test.

Results:

Patients who underwent BDG with open antegrade pulmonary blood flow (APBF) had higher saturations (oxygen saturation [SpO₂]) compared to those without it (87.5 ± 5.0% vs. 81.1 ± 4.8%; P = 0.0001). However, we found no differences in exercise parameters of patients undergoing BDG with or without APBF. Extracardiac TCPC (n = 42) patients demonstrated better exercise capacity (15.0 ± 7.7 vs. 11.2 ± 6.2 min; P = 0.02) and increased SpO₂ on exercise (87.0 ± 8.0% vs. 83.4 ± 7.6%; P ≤ 0.05) compared to lateral tunnel TCPC (n = 32). Fenestrated TCPC (n = 30) patients had higher exercise capacity reflected by higher metabolic equivalents (METs) consumption (6.4 ± 2.3 vs. 5.2 ± 2.0 METs, P = 0.02), fewer pleural effusions (7.0 ± 3.2 vs. 9.2 ± 6.2 days, P ≤ 0.05), and lower hospital stay (9.5 ± 4.0 vs. 12.7 ± 7.7 days, P = 0.04) compared to nonfenestrated TCPC (n = 44) patients.

Conclusions:

We observed no differences in exercise parameters of patients undergoing BDG with or without APBF. Extracardiac TCPC patients had better exercise capacity but longer postoperative hospital stay and pleural effusions than patients with lateral tunnel Fontan. Fenestrated TCPC patients seemed to fare better than nonfenestrated ones. Patients undergoing TCPC had better exercise capacity than patients undergoing BDG alone.

Early to mid-term results after total cavopulmonary connection performed in the second decade of life

OBJECTIVES

Total cavopulmonary connection (TCPC) performed in the second decade of life has rarely been studied. Thus, we investigated (bicentric study) early and late morbidity and mortality following completion of TCPC in these patients.

METHODS

From January 1999 to June 2014, 63 patients (14.5 ± 2.9 years) underwent TCPC (extracardiac conduit). Palliation before completion was an isolated bidirectional cavopulmonary shunt (BCPS) in 3 patients or BCPS associated with additional pulmonary blood flow (APBF) that was either antegrade (Group 1) in 38 (63%) or retrograde (Group 2) in 22 (37%). Preoperative and perioperative data were reviewed retrospectively.

RESULTS

Mean pulmonary arterial and ventricular end-diastolic pressures were 12.2 and 9.2 mmHg, respectively. Mean Nakata index was 279 ± 123 and 228 ± 87 mm 2 /m 2 in Groups 1 and 2, respectively ( P  =   0.01). Aortic cross-clamping was performed in 22 from Group 1 and 8 from Group 2 ( P  =   0.04). Mean follow-up was 4.57 years [0.8-15]. Nine patients had prolonged stays in the intensive care unit (>6 days). There were 1 early and 2 late deaths (non-cardiac related). Actuarial survival was 96% at 4 years. At last follow-up, single-ventricle function remained normal or improved in all patients (Group 1) compared to 82% in Group 2 ( P  =   0.02). New York Heart Association (NYHA) class had improved in both groups: 47 patients were NYHA class II and 16 class III preoperatively vs 50 class I and 10 class II postoperatively ( P  <   0.001).

CONCLUSIONS

Single-ventricle palliation with BCPS and APBF allowed completion of TCPC in the second decade of life, with encouraging mid-term results. However, BCPS with retrograde APBF was associated with single-ventricle dysfunction: thus, this technique needs to be used cautiously as long-lasting palliation.

Current outcomes of the bi-directional cavopulmonary anastomosis in single ventricle patients: analysis of risk factors for morbidity and mortality, and suitability for Fontan completion

OBJECTIVES

The bi-directional cavopulmonary anastomosis forms an essential staging procedure for univentricular hearts. This review aims to identify risk factors for morbidity, mortality, and suitability for Fontan completion.

METHODS

A total of 114 patients undergoing cavopulmonary anastomosis between 1992 and 2012 were reviewed to assess primary - mortality and survival to Fontan completion - and secondary outcome endpoints - re-intubation, new drain, and ICU stay. Median age and weight were 8 months and 6.9 kg, respectively. In 83% of patients, 1-3 interventions had preceded. Norwood-type procedures became more prevalent over time.

RESULTS

Extubation occurred after a median of 4 hours, median ICU stay was 2 days; 10 patients (8.8%) needed re-intubation and 18 received a new drain. Higher central venous pressure and transpulmonary gradient were risk factors for new drain insertion (p<0.01). Higher pre-operative pulmonary pressure correlated with increased inotropic support and prolonged intubation (p=0.01). Need for re-intubation was significantly affected by younger age at operation (p=0.01). Hospital and pre-Fontan mortality were 11.4 and 5.3%, respectively. Operative mortality was independently affected by younger age (p=0.013), lower weight (p=0.02), longer bypass time (p=0.04), and re-intubation (p=0.004). Interstage mortality was mainly influenced by moderate ventricular function (p=0.03); 82% of survivors underwent or are candidates for Fontan completion.

CONCLUSION

The cavopulmonary anastomosis remains associated with adverse outcomes. Age at operation decreases with rising prevalence of complex univentricular hearts. Considering the important impact of re-intubation on hospital mortality, peri-operative management should focus on optimising cardio-respiratory status. Once this selection step is taken, successful Fontan completion can be expected, provided that ventricular function is maintained.

Decision-Making for Surgery in the Management of Patients with Univentricular Heart

A series of technical refinements over the past 30 years, in combination with advances in perioperative management, have resulted in dramatic improvements in the survival of patients with univentricular heart. While the goal of single-ventricle palliation remains unchanged - normalization of the pressure and volume loads on the systemic ventricle, the strategies to achieve that goal have become more diverse. Optimal palliation relies on a thorough understanding of the changing physiology over the first years of life and the risks and consequences of each palliative strategy. This review describes how to optimize surgical decision-making in univentricular patients based on a current understanding of anatomy, physiology, and surgical palliation.

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.

Comparative outcome of bidirectional Glenn shunt in patients with pulmonary vascular resistance > or = 3.5 woods units versus < 3.5 woods units

Moderate to severe pulmonary hypertension is considered to be an absolute contraindication to the performance of bidirectional Glenn (BDG) shunting. However, BDG shunting has been performed in young children with pulmonary hypertension associated with unrestricted pulmonary blood flow. In this study, the medical records of patients who underwent BDG starting from October 2000 to March 2004 were reviewed. Patients were divided into 2 groups on the basis of indexed pulmonary vascular resistance (PVRI) measured in room air: a high-risk group (n = 12) with PVRI > or = 3.5 Woods units (WU)/m(2) and a low-risk group (n = 28) with PVRI <3.5 WU/m(2) in room air. The 2 groups were comparable with respect to age, weight, ventricular morphology, pulmonary arterial anatomy, and atrioventricular valve function. Mean pulmonary arterial pressure and PVRI were significantly higher in the high-risk group compared with the low-risk group (39.2 +/- 20.7 vs 15.1 +/- 6.25 mm Hg, p <0.002, and 6.0 +/- 2.5 vs 1.6 +/- 0.82 WU/m(2), p <0.0005, respectively). The ratio of pulmonary flow to systemic flow was 1.45 +/- 0.76 in the high-risk group and 1.24 +/- 1.2 in the low-risk group. In the high-risk group, mean PVRI decreased to 2.0 +/- 1.0 WU/m(2) on 100% oxygen (p <0.0005). A contraindication to Glenn shunting was PVRI >3.5 WU/m(2) on 100% oxygen. Hospital mortality was 17% (2 of 12) in the high-risk group and 4% (1 of 28) in the low-risk group. Of 10 survivors in the high-risk group, 1 had undergone a Kawashima procedure, 7 had undergone Fontan procedures (with 1 death), and 2 were awaiting the completion of Fontan procedures as of this writing. In conclusion, these preliminary data suggest that in young children with increased pulmonary flow, BDG shunting can be safely performed, despite the apparent elevation of pulmonary arterial pressure to inoperable levels, provided PVRI decreases to < or = 3.5 WU/m(2) on 100% oxygen.

Bidirectional Glenn and antegrade pulmonary blood flow: temporary or definitive palliation?

BACKGROUND

We sought to investigate the role of the bidirectional Glenn with antegrade pulmonary blood flow in the surgical history of children with univentricular hearts.

METHODS

A series of 246 patients, from three joint institutions, having univentricular heart with restricted but not critical pulmonary blood flow received a bidirectional cavopulmonary shunt with additional forward pulmonary blood flow. All patients have been studied according to their progression, or not, to Fontan operation. Two hundred and eight (84.5%) patients underwent bidirectional cavopulmonary anastomosis as primary palliation. Twenty patients (8.1%) with previous pulmonary artery banding were also enrolled in the study. Patients who had received additional pulmonary blood flow through a previous systemic to pulmonary artery shunt for the critical pulmonary blood flow were excluded.

RESULTS

No in-hospital death occurred. Follow-up was complete at 100%. Mean follow-up was 4.2 +/- 2.8 years (range, 6 months to 7 years). During the observational period 73 (29.7%) patients, considered optimal candidates, underwent Fontan completion for increasing cyanosis and (or) hematocrit and (or) fatigue with exertion. Three patients expired after total cavopulmonary connection (3 of 73; 4.1% mortality rate). The remaining 173 (70.3%) patients are alive with initial palliation. All patients were still well palliated with an arterial oxygen saturation at rest about 90%.

CONCLUSIONS

According to our experience and results, bidirectional Glenn with antegrade pulmonary blood flow may be an excellent temporary palliation prior to a Fontan operation, which can be performed at the onset of symptoms. Bidirectional Glenn may also be the best possible palliation for a suboptimal candidate for Fontan.

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.