Uncontrolled Antegrade Pulmonary Blood Flow and Delayed Fontan Completion After the Bidirectional Glenn Procedure: Real-World Outcomes in China

Utility of Balloon Occlusion Testing in Determining Fontan Suitability Among Patients with Elevated Pulmonary Artery Pressure and Additional Antegrade Pulmonary Blood Flow

In individuals with a single ventricle undergoing evaluation before Fontan surgery, the presence of excessive pulmonary blood flow can contribute to increased pulmonary artery pressure, notably in those who had a Glenn procedure with antegrade pulmonary flow. 28 patients who had previously undergone Glenn anastomosis with antegrade pulmonary blood flow (APBF) and with elevated mean pulmonary artery (mPAP) pressure > 15 mmHg in diagnostic catheter angiography were included in the study. After addressing other anatomical factors that could affect pulmonary artery pressure, APBF was occluded with semi-compliant, Wedge or sizing balloons to measure pulmonary artery pressure accurately. 23 patients (82% of the cohort) advanced to Fontan completion. In this group, median mPAP dropped from 20.5 (IQR 19-22) mmHg to 13 (IQR 12-14) mmHg post-test (p < 0.001). Median PVR post-test was 1.8 (IQR 1.5-2.1) WU m2. SpO2 levels decreased from a median of 88% (IQR 86%-93%) pre-test to 80% (IQR 75%-84%) post-test (p < 0.001). In five patients, elevated mPAP post-test occlusion on diagnostic catheter angiography led to non-completion of Fontan circulation. In this group, median pre- and post-test mPAP were 23 mmHg (IQR 21.5-23.5) and 19 mmHg (IQR 18.5-20), respectively (p = 0.038). Median post-test PVR was 3.8 (IQR 3.6-4.5) WU m2. SpO2 levels decreased from a median of 79% (IQR 76%-81%) pre-test to 77% (IQR 73.5%-80%) post-test (p = 0.039). Our study presents a specialized approach for patients initially deemed unsuitable for Fontan due to elevated pulmonary artery pressures. We were able to successfully complete the Fontan procedure in the majority of these high-risk cases after temporary balloon occlusion test.

Does Maintenance of Pulmonary Blood Flow Pulsatility at the Time of the Fontan Operation Improve Hemodynamic Outcome in Functionally Univentricular Hearts?

It is unclear whether residual anterograde pulmonary blood flow (APBF) at the time of Fontan is beneficial. Pulsatile pulmonary flow may be important in maintaining a compliant and healthy vascular circuit. We, therefore, wished to ascertain whether there was hemodynamic evidence that residual pulsatile flow at time of Fontan promotes clinical benefit. 106 consecutive children with Fontan completion (1999-2018) were included. Pulmonary artery pulsatility index (PI, (systolic pressure-diastolic pressure)/mean pressure)) was calculated from preoperative cardiac catheterization. Spectral analysis charted PI as a continuum against clinical outcome. The population was subsequently divided into three pulsatility subgroups to facilitate further comparison. Median PI prior to Fontan was 0.236 (range 0-1). 39 had APBF, in whom PI was significantly greater (median: 0.364 vs. 0.177, Mann-Whitney p < 0.0001). There were four early hospital deaths (3.77%), and PI in these patients ranged from 0.214 to 0.423. There was no correlation between PI and standard cardiac surgical outcomes or systemic oxygen saturation at discharge. Median follow-up time was 4.33 years (range 0.0273-19.6), with no late deaths. Increased pulsatility was associated with higher oxygen saturations in the long term, but there was no difference in reported exercise tolerance (Ross), ventricular function, or atrioventricular valve regurgitation at follow-up. PI in those with Fontan-associated complications or the requiring pulmonary vasodilators aligned with the overall population median. Maintenance of pulmonary flow pulsatility did not alter short-term outcomes or long-term prognosis following Fontan although it tended to increase postoperative oxygen saturations, which may be beneficial in later life.

Long-term results of additional pulmonary blood flow with bidirectional cavopulmonary shunt

Objective

We evaluated additional pulmonary blood flow at the time of bidirectional cavopulmonary shunt and its effects on the Fontan procedure and long-term outcome of Fontan circulation and liver function.

Methods

We included 22 patients (16 boys, 6 girls) having undergone bidirectional cavopulmonary shunt with additional pulmonary blood flow between April 2002 and January 2016. Mean age and body weight were 20 ± 13 months and 7.5 ± 6.5 kg, respectively. We retrospectively evaluated the patients’ clinical data, including cardiac catheterization data, liver function, and liver fibrosis markers.

Results

All patients were alive with a New York Heart Association status of I at the long-term follow-up. Changes between pre-bidirectional cavopulmonary shunt and 101 months after the Fontan procedure included the following: the cardiothoracic ratio of chest X-ray decreased from 52.2 ± 3.9% to 41.8 ± 5.9% (p < 0.001); systemic ventricle end-diastolic pressure decreased from 11.4 ± 3.2 mmHg to 6.9 ± 3.6 mmHg (p < 0.001); and the pulmonary artery index decreased from 485.1 ± 272.3 to 269.5 ± 100.5 (p = 0.02). Type IV collagen, hyaluronic acid, and procollagen levels increased over the normal range 116 months after the Fontan procedure.

Conclusions

The additional pulmonary blood flow at the time of bidirectional cavopulmonary shunt may contribute to pulmonary arterial growth at the Fontan procedure with low pulmonary arterial resistance and without ventricle volume overload. The Fontan circulation was well-maintained at the long-term follow-up, while liver fibrosis markers were above their normal values.

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.

Effectiveness of Bidirectional Glenn Shunt Placement for Palliation in Complex Congenitally Corrected Transposed Great Arteries

Surgery for complex congenitally corrected transposed great arteries is one of the greatest challenges in cardiovascular surgery. We report our experience with bidirectional Glenn shunt placement as a palliative procedure for complex congenitally corrected transposition. We retrospectively identified 50 consecutive patients who had been diagnosed with congenitally corrected transposition accompanied by left ventricular outflow tract obstruction and ventricular septal defect and who had then undergone palliative bidirectional Glenn shunt placement at our institution from January 2005 through December 2014. Patients were divided into 3 groups according to subsequent surgeries: Fontan completion (total cavopulmonary connection, 13 patients) (group 1), anatomic repair (hemi-Mustard and Rastelli procedures without Glenn takedown, 11 patients) (group 2), and prolonged palliation (no further surgery, 26 patients) (group 3). After shunt placement, no patient died or had ventricular dysfunction. Overall, mean oxygen saturation increased significantly from 79.5% ± 13.5% preoperatively to 94.1% ± 7.3% (P <0.001). The median time from shunt placement to Fontan completion and anatomic repair, respectively, was 2.1 years (range, 1.6-5.2 yr) and 1.1 years (range, 0.6-2.4 yr). Only 2 late deaths occurred, both in group 1. In group 3, time from shunt placement to latest follow-up was 4.5 years (range, 2.3-8 yr). At latest follow-up, mean oxygen saturation was 91.6% ± 10.3%, and no patients had impaired ventricular function. Bidirectional Glenn shunt placement as an optional palliative procedure for complex congenitally corrected transposition has favorable outcomes. Later, patients can feasibly be treated by Fontan completion or anatomic repair. Use of a bidirectional Glenn shunt for open-ended palliation is also acceptable.

Pulsatile Glenn as long-term palliation for single ventricle physiology patients

OBJECTIVE

There are limited studies analyzing pulsatile Glenn as a long-term palliation strategy for single ventricle patients. This study sought to determine their outcomes at a single institution.

DESIGN

A retrospective review was performed.

SETTING

Study performed at a single pediatric hospital.

PATIENTS

All single ventricle patients who underwent pulsatile Glenn from 1995 to 2016 were included.

OUTCOME MEASURES

Pulsatile Glenn failure was defined as takedown, transplant, or death. Further palliation was defined as Fontan, 1.5, or biventricular repair. Risk factors were assessed by Cox multivariable competing risk analyses.

RESULTS

Seventy-eight patients underwent pulsatile Glenn at age 9 months (interquartile range, 5-14). In total, 28% had heterotaxy, 18% had a genetic syndrome, and 24% had an abnormal inferior vena cava. There were 3 (4%) perioperative mortalities. Further palliation was performed in 41 (53%) patients with a median time-to-palliation of 4 years (interquartile range, 3-5). Pulsatile Glenn failure occurred in 10 (13%) patients with 8 total mortalities. Five- and 10-year transplant-free survival were 91% and 84%, respectively. At a median follow-up of 6 years (interquartile range, 2-8), 27 patients (35%) remained with PG (age 7 years [interquartile range, 3-11], oxygen saturation 83% ± 4%). Preoperative moderate-severe atrioventricular valve regurgitation (AVVR) (hazard ratio 7.77; 95% confidence interval 1.80-33.43; P =.005) and higher pulmonary vascular resistance (hazard ratio 2.59; 95% confidence interval 1.08-6.15; P =.031) were predictors of pulsatile Glenn failure after adjusting for covariates. Reaching further palliation was less likely in patients with preoperative moderate-severe AVVR (hazard ratio 0.22, 95% confidence interval 0.08-0.59; P =.002).

CONCLUSION

Pulsatile Glenn can be an effective tool to be used in challenging circumstances, these patients can have a favorable long-term prognosis without reducing their suitability for further palliation.

The effect of antegrade pulmonary blood flow following a late bidirectional Glenn procedure

OBJECTIVES

The effect of antegrade pulmonary blood flow (APBF) has never been studied in the bidirectional Glenn (BDG) procedure performed late.

METHODS

Records of 112 consecutive patients who had a BDG procedure during a 10-year period were reviewed retrospectively. The patients were divided into 2 groups based on whether APBF occurred following the BDG procedure (APBF group, n = 81) or not (non-APBF group, n = 31). The median age at the BDG procedure was 6.16 ± 3.93 years in the APBF group and 6.12 ± 4.40 years in the non-APBF group.

RESULTS

Demographics and pre- and intraoperative variables were comparable for both groups. Follow-up data were obtained for patients at the BDG stage and for those who had undergone the Fontan completion. Both oxygen saturation levels (81.72 ± 1.976% vs 78.32 ± 2.344%, P < 0.01) and pulmonary pressure (13.59 ± 1.376 mmHg vs 12.90 ± 0.978 mmHg, P = 0.012) were higher in the APBF group immediately after the BDG procedure. Both the duration of chest tube drainage and the total length of stay were longer in the APBF group. The pre-Glenn measurements showed a mean McGoon ratio of 1.68 ± 0.114 in the APBF group and 1.67 ± 0.098 in the non-APBF group (P = 0.474). The McGoon ratios measured before the Fontan procedure were also comparable (1.669 ± 0.726 vs 1.685 ± 0.669, P = 0.576). At the pre-Fontan measurement, there was no significant difference in mean pulmonary artery pressures between the groups (13.72 ± 1.368 vs 13.50 ± 1.265, P = 0.653). Fifty-nine patients underwent the Fontan completion (43 from the APBF group and 16 from the non-APBF group) procedure with a median of 1.2 (APBF group) and 1.4 (non-APBF group) years after the BDG procedure. No significant differences between groups were observed in arterial oxygen saturation levels, incidence of systemic atrioventricular valve regurgitation or ventricular dysfunction in survivors at the last follow-up visit.

CONCLUSIONS

The BDG procedure can be safely performed at a relatively older age (∼6 years). APBF increases oxygen saturation but also prolongs pleural effusion and hospital stay. Medium-term outcomes and the Fontan completion rate in the APBF and the non-APBF groups are comparable. Further large studies and long-term follow-up are needed to clarify the effect of APBF in patients who have the late BDG.

Factors determining early outcomes after the bidirectional superior cavopulmonary anastomosis

Objective

The bidirectional Glenn (BDG) procedure is a step in multistage palliation of univentricular heart (UVH). We aimed to report the factors determining the outcomes following BDG.

Methods

Two hundred fifteen consecutive patients, 5.29 ± 5 years (range 1 month to 38 years, median 3 years) of age, weighing 13 ± 8.8 kg (range 2.6 to 51 kg, median 10 kg) with variable forms of UVH underwent BDG from 2003 to 2013. Their clinical records were reviewed retrospectively.

Results

The most common anatomic diagnoses were tricuspid atresia (n = 87, 40.5%) and double outlet right ventricle (n = 78, 36%). Dextrocardia was present in 21 (9.86%) patients. Median left pulmonary (PA) and right PA diameters were 6 and 7 mm, respectively. One hundred sixty-two (77%) patients received unilateral BDG, and 45 had bilateral BDG. The antegrade pulmonary blood flow was closed in 199 and was left open in 16 patients. Concomitant procedures were reconstruction of pulmonary arteries for non-confluent PA (n = 28), atrial septectomy (n = 15), atrioventricular valve repair (n = 12) and repair of partial anomalous pulmonary venous connection (n = 1). A total of 37% of patients (n = 80) had a mean post-operative saturation of 90 ± 3.2%. There were four (1.86%) early deaths. Mean Glenn pressure was 14.7 ± 3.5 mm Hg, and mean inotropic score and Vasoactive inotropic score (VIS) were 1.64 ± 0.96 and 2.77 ± 2.63, respectively. Mean intensive care unit stay was 24.1 ± 26.4 (range 10-240) h, and mean duration of hospital stay was 7.15 ± 3.2 days. Mean saturation at the time of discharge was 92.4 ± 2.2% and on follow-up was 82 ± 2.16%. Follow-up cardiac catheterization data was available in 123 (60.3%). Sixty-nine (33.8%) patients underwent completion Fontan, and 135 patients were in follow-up or waiting for Fontan completion.

Conclusion

BDG procedure can be performed safely with acceptable mortality. Age at presentation, pulmonary artery size and VIS were not related to mortality. Younger patients had similar outcomes but a longer hospital stay. Patients with preserved antegrade pulmonary blood flow had higher saturations. Those undergoing BDG without cardiopulmonary bypass had lower inotropic scores.