Does an additional source of pulmonary blood flow alter outcome after a bidirectional cavopulmonary shunt?

Does leaving native antegrade pulmonary blood flow at the time of the superior cavopulmonary connection impact long-term outcomes after the Fontan?

Objectives

Antegrade pulmonary blood flow (APBF) may be left or eliminated at the time of the superior cavopulmonary connection (SCPC). Our aim was to assess the impact of leaving native APBF at the SCPC on long-term Fontan outcomes.

Methods

In the Australia and New Zealand Fontan Registry (1985-2021), 587 patients had pre-existing native APBF at the SCPC. At the SCPC, 302 patients had APBF eliminated (APBF-) and 285 patients had APBF maintained (APBF+). The incidence of Fontan failure (composite end point of Fontan takedown, transplant, plastic bronchitis, protein losing enteropathy and death) and atrioventricular (AV) valve repair/replacement post SCPC was compared between the 2 groups.

Results

Sex, predominant-ventricle morphology, isomerism, primary diagnosis, and age/type of Fontan were similar between groups. APBF- versus APBF+ had a higher incidence of arch obstruction/coarctation (17% vs 7%) and previous pulmonary artery band (54% vs 45%) and a lower rate of Fontan fenestration (27% vs 41%). The risk of Fontan failure was similar between the 2 groups (hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.58-1.78; P = .96). The risk of AV-valve repair/replacement was greater in APBF+ versus APBF- (HR, 2.32; CI, 1.13-4.75; P = .022). The risk of AV-valve repair/replacement remained after adjustment for arch obstruction/coarctation, previous pulmonary artery band and Fontan fenestration (HR, 2.27; CI, 1.07-4.81; P = .033).

Conclusions

Maintaining APBF at the time of the SCPC does not impact the risk of Fontan failure but may increase the incidence of AV-valve repair and/or replacement post-SCPC.

Device Occlusion of Native Pulmonary Blood Flow After Cavopulmonary Anastomosis With Persistent Pleural Effusions

Native pulmonary tract flow after a cavopulmonary anastomosis may promote pulmonary artery growth but can lead to undesirable consequences. We report the case of a 17-month child with prolonged pleural effusions after cavopulmonary anastomosis in whom a ventricular septal defect occluder device was placed in the native right ventricular outflow tract. (Level of Difficulty: Advanced.).

One and One-Half Ventricle Repair: Role for Restricting Antegrade Pulmonary Blood Flow

BACKGROUND

In patients with hypoplastic subpulmonary ventricles, the one and one-half ventricle (1.5V) repair is an alternative to the Fontan procedure. However, in 1.5V-treated patients with pulsatile pulmonary blood flow, superior vena cava (SVC) hypertension or right atrial hypertension may develop. This study aimed to (1) describe patient outcomes after 1.5V repair and (2) determine whether pulmonary artery septation at 1.5V repair confers a lower risk of SVC or right atrial hypertension.

METHODS

This study retrospectively reviewed patients who underwent a 1.5V repair between 1989 and 2020. The primary outcome was transplant-free survival. Secondary outcomes were postoperative SVC hypertension (defined by mean Glenn pressures greater than 17 mm Hg, SVC flow reversal or pulsatility, venovenous collateral vessels, or SVC syndrome) and right atrial hypertension (defined as mean right atrial pressures greater than 10 mm Hg with inferior vena cava and hepatic vein dilation or flow reversal).

RESULTS

A total of 74 patients underwent 1.5V repair at a median age of 29.6 months (interquartile range, 8.9 to 45.5 months). Median follow-up time was 39.9 months (interquartile range, 11.4 to 178.1 months). Transplant-free survival at 10 years was 92.4%. Among survivors, 12% (8 of 69) had right atrial hypertension and 39% (27 of 69) had SVC hypertension on follow-up. Survivors with unseptated pulmonary arteries had a greater risk of SVC hypertension compared with patients with septated pulmonary arteries (44% vs 10%; P = .04). No difference was found in right atrial hypertension between the 2 groups.

CONCLUSIONS

Patients with 1.5V repair avoid Fontan-associated complications with favorable transplant-free survival. However, SVC hypertension remains a significant long-term complication. Pulmonary artery septation at 1.5V repair may reduce the risk of SVC hypertension.

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.

The Glenn procedure: Clinical outcomes in patients with congenital heart disease in pakistan

Objectives:

Congenital heart defects (CHDs) affect more than 40,000 children annually in Pakistan. Approximately 80% of patients require at least one surgical intervention to achieve a complete or palliative cardiac repair. The Glenn shunt, a palliative procedure is established between superior vena cava (SVC) and the right pulmonary artery to provide an anastomosis offering minimal risk to patients with univentricular heart disease. The aim of this study was to assess the clinical outcomes of the Glenn shunt procedure in patients with complex congenital heart diseases in a developing country like Pakistan.

Materials and Methods:

A retrospective chart review was conducted on patients who underwent a bidirectional Glenn shunt procedure from July 2006 to June 2017. Data were collected on a structured questionnaire and analyses performed on SPSS version 22. Frequencies and percentages were computed for categorical variables while mean and standard deviation for continuous variables where appropriate.

Results:

A total of 79 patients underwent the Glenn shunt procedures. The median age was 1.9 years and 54.5% were male. Tricuspid atresia was the primary diagnosis in 30.4% of the patients. Common morbidities included arrhythmias (6.3%), pleural effusion (8.9%), wound infection (3.8%), pneumonia (2.5%), and seizures (3.8%); reopening was required in 2.5% of the patients and 8.8% were readmitted within 30 days of index operation. There were three (3.8%) deaths in total.

Conclusions:

Bidirectional Glenn shunt procedure can be performed safely in patients with ideal characteristics as the first stage palliation and has favorable results with acceptable rate of complications.

Post-Fontan pulmonary artery growth in patients with a bidirectional cavopulmonary shunt with additional antegrade pulsatile blood flow

Background

Patients with antegrade pulmonary blood flow after a bidirectional cavopulmonary shunt (Glenn) may have better pulmonary artery growth. This study evaluated pulmonary artery growth in patients with and without prior additional pulsatile antegrade flow in a Glenn shunt at midterm follow-up after a Fontan procedure.

Methods

We reviewed 212 patients who had single-ventricle palliation in a 10-year period;103 (33 in pulsatile group 1 and 70 in nonpulsatile group 2) were selected for analysis. Data on demographics, procedures, perioperative course, and midterm follow-up after the Fontan procedure were compared. Echocardiography data were collected. Pulmonary artery sizes measured at cardiac catheterization and follow-up echocardiograms were used to calculate the Nakata index.

Results

Perioperative details were comparable in both groups, mean pulmonary artery pressure and systemic oxygen saturations were higher in group 1 compared to group 2. Venovenous collaterals were increased in group 1. There was a significant difference in the pre-Fontan and follow-up Nakata index between groups. There was a significant increase in the Nakata index in group 1 between the pre-Glenn and pre-Fontan assessments as well as the Nakata index between the pre-Fontan and midterm follow-up. There was no significant change in the Nakata index in group 2 between assessments.

Conclusions

A pulsatile Glenn shunt is associated with better pulmonary artery growth which continues long after the additional pulsatile flow is eliminated. It is possible that the effects of anterograde pulmonary blood flow on pulmonary artery growth in early life continue long after the Fontan completion.

Transcatheter occlusion of antegrade pulmonary blood flow in children with univentricular heart

Background

This study aims to evaluate the results of transcatheter occlusion of antegrade pulmonary blood flow in children with univentricular heart.

Methods

Medical data of a total of seven patients (4 females, 3 males; median age 11.7 years; range, 1 to 24 years) who underwent transcatheter occlusion of the antegrade pulmonary blood flow following Glenn shunt or Fontan operation between September 2014 and January 2017 were retrospectively analyzed. Data including demographic and clinical characteristics of the patients, type of surgery, echocardiographic and cardiac catheterization findings were recorded.

Results

Four patients had a previous pulmonary artery banding operation, while three had pulmonary stenosis. Two patients had facial and upper extremity edema after Glenn operation, one had prolonged pleural effusion, one had prolonged pleural effusion after Fontan operation, and one developed dyspnea and effort intolerance several years after Fontan operation. In two patients, antegrade pulmonary blood flow was occluded to decrease systemic ventricular load before surgery. The Amplatzer Septal Occluder was used in five patients and the Amplatzer Vascular Plug-2 was used in two patients. Two patients developed transient, complete atrioventricular block during the procedure and the procedure was terminated early in one of these patients. Transient hemolysis was observed in one patient following the operation.

Conclusion

Transcatheter occlusion of antegrade pulmonary blood flow is an effective alternative to surgery in patients with hemodynamic compromise after Glenn shunt or Fontan operation.

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.

Patients With Systemic Right Ventricle Are at Higher Risk of Chylothorax After Cavopulmonary Connections

BACKGROUND

Chylothorax is a rare but severe complication after pediatric cardiac surgical procedures and is related to significant morbidity and mortality. It is suspected to be more frequent after single-ventricle staged palliation procedures, but focused studies on chylothorax in patients with univentricular heart physiology are scarce.

METHODS

From January 2008 to December 2016, a total of 289 patients underwent 376 cavopulmonary connection (CPC) procedures over 9 years (superior cavopulmonary connection [SCPC], 199; Fontan completion, 177). Patients were classified according to whether they had a chylothorax (group 1) or not (group 2). Chylothorax was confirmed on a pleural fluid test.

RESULTS

The rate of chylothorax after a CPC procedure was 19.7% (74 of 376): 15.6% after SCPC and 24.3% after Fontan completion. Mean follow-up was 4.3 ± 0.1 years. Systemic right ventricle was more frequent in group 1 than in group 2 (64.9% vs 46%, respectively; p = 0.003). Chylothorax was associated with a higher rate of early reoperation (p = 0.001) and late failure of the CPC (p < 0.001). Late mortality was also more frequent in group 1 than in group 2 (17.6% vs 4.3%; p < 0.001). By multivariate analysis, having a systemic right ventricle was the only identified predictor for the development of chylothorax (odds ratio, 2.49; 95% confidence interval, 1.4 to 4.7; p = 0.004).

CONCLUSIONS

The incidence of chylothorax in patients undergoing the univentricular pathway procedure is higher than previously suggested. Having a systemic right ventricle is a significant risk factor for developing a chylothorax after a CPC.

One and half ventricle repair: rationale, indications, and results

Surgical strategies in patients with functionally or anatomically borderline right ventricles include a high-risk biventricular repair, a Fontan procedure, or a one and half ventricle repair (also referred to as the partial biventricular repair). One and half ventricle repair (1.5VR) circumvents the high early mortality of a biventricular repair and also the late morbidity of the Fontan. The two most common indications for a 1.5VR are a small pulmonary ventricle and a dilated poorly functioning pulmonary ventricle. Extension of 1.5VR to patients undergoing anatomical repair for congenitally corrected transposition of great arteries, straddling tricuspid valves, and severe Ebstein's anomaly has facilitated biventricular repair with decreased mortality. We reviewed the relevant literature on this subject in detail and describe its rationale, indications and its early and late results.

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.

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.

In Vitro Assessment of the Assisted Bidirectional Glenn Procedure for Stage One Single Ventricle Repair

This in vitro study compares the hemodynamic performance of the Norwood and the Glenn circulations to assess the performance of a novel assisted bidirectional Glenn (ABG) procedure for stage one single ventricle surgery. In the ABG, the flow in a bidirectional Glenn procedure is assisted by injection of a high-energy flow stream from the systemic circulation using an aorta-caval shunt with nozzle. The aim is to explore experimentally the potential of the ABG as a surgical alternative to current surgical practice. The experiments are directly compared against previously published numerical simulations. A multiscale mock circulatory system was used to measure the hemodynamic performance of the three circulations. For each circulation, the system was tested using both low and high values of pulmonary vascular resistance. Resulting parameters measured were: pressure and flow rate at left/right pulmonary artery and superior vena cava (SVC). Systemic oxygen delivery (OD) was calculated. A parametric study of the ratio of ABG nozzle to shunt diameter was done. We report time-based comparisons with numerical simulations for the three surgical variants tested. The ABG circulation demonstrated an increase of 30-38% in pulmonary flow with a 2-3.7 mmHg increase in SVC pressure compared to the Glenn and a 4-14% higher systemic OD than either the Norwood or the Glenn. The nozzle/shunt diameter ratio affected the local hemodynamics. These experimental results agreed with those of the numerical model: mean flow values were not significantly different (p > 0.05) while mean pressures were comparable within 1.2 mmHg. The results verify the approaches providing two tools to study this complicated circulation. Using a realistic experimental model we demonstrate the performance of a novel surgical procedure with potential to improve patient hemodynamics in early palliation of the univentricular circulation.

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.

Results of additional pulsatile pulmonary blood flow with bidirectional glenn cavopulmonary anastomosis: positive effect on main pulmonary artery growth and less need for fontan conversion

BACKGROUND

Additional antegrade pulsatile pulmonary blood flow obtained by leaving the main pulmonary artery patent during bidirectional cavopulmonary shunt has been shown to give additional benefits to the bidirectional Glenn cavopulmonary anastomosis. We retrospectively evaluated our 20-patient pulsatile Glenn series in order to find out whether these salutary effects were valid or not.

METHODS

Between June 2007 and November 2011, 20 patients (11 girls and 9 boys) with single-ventricle physiology underwent bidirectional cavopulmonary anastomosis. The additional source of blood flow was through the unligated main pulmonary artery in all patients. A retrospective review of our surgical experience was performed focusing on the role of additional pulmonary flow. Medical records and perioperational and postoperative follow-up data including clinical outcomes were retrospectively retrieved and analyzed.

RESULTS

Two patients died in the early postoperative period. One patient died in the follow-up period. Mean follow-up time was 23.9 ± 15.7 months. No superior vena cava syndrome and no increase in pulmonary vascular resistance were observed. Improvement of partial oxygen pressure after pulsatile Glenn has been shown in all patients (P = .00). At a mean interval of 22.9 months, main pulmonary artery size continued to increase after pulsatile Glenn cavopulmonary anastomosis (P = .028). Only 1 patient was converted to Fontan type circulation after pulsatile Glenn cavopulmonary anastomosis.

CONCLUSIONS

The pulsatile cavopulmonary shunt is a useful procedure in the early and intermediate term management of patients with a functional univentricular heart. It improves partial oxygen pressure and the impact of pulsatility on the main pulmonary artery.

Cavopulmonary anastomosis without cardiopulmonary bypass

OBJECTIVES

There is an increasing trend to perform the bidirectional superior cavopulmonary (Glenn) anastomosis without cardiopulmonary bypass. In this report, we present our results of off-pump bidirectional Glenn operation done without using a venoatrial shunt to decompress the superior vena cava during clamping. [corrected].

METHODS

A prospective, non-randomized comparative study was conducted in 50 patients with functional single ventricle anomalies who underwent bidirectional Glenn anastomosis without cardiopulmonary bypass. The patients were divided into two groups: Group I (n = 25), where it was done without a veno-atrial shunt, and Group II (n = 25), where it was done with a veno-atrial shunt. Two patients in Group I and 4 patients in Group II had a bilateral bidirectional Glenn shunt. Five patients in Group I and three patients in Group II had a previous left modified Blalock-Taussig shunt. All patients underwent a complete neurological examination both preoperatively as well as postoperatively.

RESULTS

The early hospital mortality was 4% (2/50), one in each group. The median follow-up was 14 months. The mean internal venous pressure on clamping the superior vena cava was 37.07 ± 7.12 mmHg in Group I and 24 ± 4.4 mmHg in Group II. The mean clamp time was 9.85 ± 3.52 min in Group I and 21.3 ± 4.4 min in Group II. The transcranial pressure gradient was 62.37 ± 15.01 mmHg in Group I, while 65.08 ± 13.89 in Group II. The mean intensive care unit stay was 2.57 ± 75 days in Group I, 3.3 ± 1.09 in Group II. There were no major neurological complications apart from treatable convulsions in one case in Group I (4%), 2 cases in Group II (8%), and delayed recovery in one case (4%) in Group I.

CONCLUSIONS

Off-pump bidirectional Glenn operation without caval decompression is a safe, simple and more economic procedure.

Intact right ventricle-pulmonary artery shunt after stage 2 palliation in hypoplastic left heart syndrome improves pulmonary artery growth

For patients with hypoplastic left heart syndrome who have undergone the Norwood procedure with a right ventricle-pulmonary artery (RV-PA) shunt, the shunt can either be removed or left intact at the time of the stage 2 procedure. This study aimed to determine the effects of an intact shunt on pulmonary artery growth and clinical outcomes after the stage 2 procedure. A retrospective review of patients who underwent Norwood with an RV-PA shunt from 2005 to 2010 was performed. Catheterization data, echocardiographic data, postoperative outcome variables, and mortality data were collected. Pulmonary artery size was measured at pre-stage 2 and pre-Fontan catheterizations using the Nakata Index and the McGoon Ratio. Of the 68 patients included in the study, 48 had the shunt removed at the time of stage 2 (group 1), and 20 had the shunt left intact (group 2). The two groups did not differ in terms of pre-stage 2 hemodynamics or pulmonary artery size. After stage 2, group 2 had higher oxygen saturations. The two groups did not differ regarding duration of chest tube drainage, length of hospital stay, need for unplanned interventions, or mortality. Before Fontan, the group 2 patients had higher superior vena cava (SVC) pressures and more venovenous collaterals closed. There was increased pulmonary artery growth between the pre-stage 2 and pre-Fontan catheterizations in group 2 using both the Nakata Index (+148.5 vs -52.4 mm(2)/m(2); p = 0.01) and the McGoon Ratio (+0.36 vs +0.01; p = 0.01). These findings indicate that patients with an intact RV-PA shunt after stage 2 have greater pulmonary artery growth than patients with the shunt removed, with no increased risk of complications.

Is additional pulsatile pulmonary blood flow beneficial to patients with bidirectional Glenn?

OBJECTIVE

To compare the results of bidirectional Glenn when performed with or without pulsatile pulmonary blood flow in a cohort of patients with a single ventricle.

METHODS

Records of 212 patients undergoing staged single ventricle palliation during a 10-year period were retrospectively reviewed. Of those, 103 (33 in pulsatile group A and 70 in nonpulsatile group B) were selected.

RESULTS

Demographics and pre- and intraoperative variables were comparable for both groups. There was no difference in oxygen saturations immediately after the bidirectional Glenn in the 2 groups. The duration and output of chest tube drainage, incidence of chylothorax, and total length of stay was higher in group A. There was no difference in the number of diuretics or oxygen requirement upon discharge between groups. Pre-Glenn measurements showed a mean McGoon ratio in group A of 1.5 (1.46-1.57) and in group B of 1.59 (1.53-1.7) (P = .11); however, there was a significant difference in the ratio between groups at pre-Fontan measurements: group A, 1.76 (1.73-1.79) and group B, 1.6 (1.53-1.66) (P < .05). At pre-Fontan measurements there was a significant difference in mean pulmonary artery pressure between group A (14 mm [12.8-15.2]) and group B (10 mm [9.7-11]) (P < .05) and a trend toward higher incidence of venovenous collaterals in group A. There was no perioperative or interstage mortality in either group.

CONCLUSIONS

Pulsatile bidirectional Glenn is associated with better pulmonary artery growth, which might improve long-term outcomes after Fontan. However, it was associated with a higher postoperative complication rate.

Single ventricle physiology: surgical options, indications and outcomes

PURPOSE OF REVIEW

Among the most frequently encountered congenital heart malformations are those with so-called single ventricle physiology, in which there is only one ventricle to pump blood to the pulmonary and systemic vascular beds, respectively. Long-term survival is possible, based on the principle of right heart bypass, whereby the ventricle pumps blood only to the systemic circuit, whereas pulmonary blood flow occurs passively. Such a circulatory system is achieved in a series of staged reconstructive operations, each of which was formerly accompanied by very high rates of major morbidity and mortality. Current approaches to single ventricle physiology as well as areas of controversy will be reviewed.

RECENT FINDINGS

The development of a number of inventive operations, combined with a greater understanding of the physiologic requirements for success after single ventricle reconstruction has resulted in dramatic improvements in outcomes. The identification and modification of risk factors as well as the recent development of catheter-based intervention offer the real prospect of significant continued improvement.

SUMMARY

Advances in the care of children with single ventricle hearts have resulted in remarkably improved prognosis, with the expectation of continued improvement in not only survival but also quality of life.

Transcatheter occlusion of antegrade pulmonary flow in children after cavopulmonary anastomosis

OBJECTIVE

To report our experience with transcatheter occlusion of antegrade pulmonary blood flow (APF) for postoperative complications of cavopulmonary anastomosis (BCPA).

BACKGROUND

It has been suggested that limited APF enhances pulmonary arterial growth in patients undergoing BCPA. However, APF may result in suboptimal postoperative hemodynamics and sequelae such as SVC syndrome or prolonged chest tube drainage. For this subgroup, closure of APF may alleviate these problems.

METHODS

All BCPA procedures where APF was left open from 1995-2005 were reviewed. Symptomatic patients with APF who underwent a cardiac catheterization in the postoperative period comprised the study cohort.

RESULTS

179 BCPA procedures were performed during the study period. APF was left patent in 29/179. 6/29 patients (age 10-28 months, median 14 months) presented 12 to 130 day; (median 31 days) with persistent pleural effusions (5) or SVC syndrome (1, Five had a history of a previous pulmonary arterial band (PAB) and one pulmonary stenosis. PA pressure was elevated in all (range 17-27 mmHg; median 22 mmHg). Hemodynamic evaluation with temporary APF occlusion was repeated in all patients. APF was successfully closed in 4/6 patients. The Amplatzer POA occluder was used in 3 and the Amplatzer ASD occluder in 1. Pulmonary effusions resolved in all the patients who had transcatheter APF closure as did the case of SVC syndrome. There were no complications.

CONCLUSION

Transcatheter APF occlusion seems both safe and feasible in patients with hemodynamic compromise following BCPA with residual APF. Temporary occlusion testing prior to permanent device closure is recommended.

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.

Persistent antegrade pulmonary blood flow post-glenn does not alter early post-Fontan outcomes in single-ventricle patients

BACKGROUND

The bidirectional Glenn cavopulmonary anastomosis (BDG) represents the standard interim procedure in treatment of patients with single-ventricle physiology. Anterograde pulmonary blood flow (APBF) maintained after BDG has been shown both to improve and to complicate postoperative clinical course. We studied its effects on outcome after BDG and eventual Fontan completion.

METHODS

From November 1995 to November 2005, 60 patients underwent BDG and Fontan. All patients had APBF from the ventricle to the pulmonary artery at time of BDG. In group 1 (n = 39) APBF was maintained after BDG, whereas APBF was interrupted at BDG in group 2 (n = 21). Cardiac catheterization data, interstage morbidity, and postoperative outcome variables were recorded.

RESULTS

Pre-BDG hemodynamics differed only in that the mean pulmonary artery pressure was higher in group 2 (17.0 +/- 4.4 mm Hg) than in group 1 (13.8 +/- 4.5 mm Hg; p = 0.03). There were no differences between groups 1 and 2 in BDG outcome variables. At pre-Fontan catheterization, group 1 had higher mean pulmonary artery pressure (13.3 versus 10.9 mm Hg, p = 0.01), arterial oxygen saturation (85.8 versus 80.9%, p = 0.0001), and fewer collateral vessels were coil embolized than in group 2 (0.9 versus 1.6, p = 0.02). Mean ventricular end-diastolic pressure was similar between groups. The Nakata index in group 1 remained stable from pre-BDG to pre-Fontan (348 versus 391, p = 0.24), but it decreased in group 2 (375 versus 227, p = 0.046).

CONCLUSIONS

Patients with anterograde pulmonary blood flow after BDG had a modest increase in pulmonary artery growth and arterial oxygen saturations, and decreased collateral vessel formation. This did not, however, confer additional benefit on outcome after BDG or on eventual Fontan completion.

Appropriate additional pulmonary blood flow at the bidirectional Glenn procedure is useful for completion of total cavopulmonary connection

BACKGROUND

The role and effect of additional pulmonary blood flow at the time of bidirectional Glenn procedure (BDG) is controversial. We assessed our experiences to clarify the effects of controlled additional pulmonary blood flow on outcomes after BDG.

METHODS

Thirty-eight patients who underwent BDG (2.1 +/- 2.1 years of age) were enrolled in this study. In group A (n = 29) additional pulmonary blood flow was controlled by the banding of the pulmonary trunk, or the previously created Blalock-Taussig shunt, to keep the central venous pressure equal to or less than 16 mm Hg at BDG. In group B (n = 9), BDG was the only source of pulmonary blood flow.

RESULTS

One operative death occurred in group B. In group A, 24 patients underwent total cavopulmonary connection (TCPC) 14 +/- 6 months after BDG, and the remaining 5 patients are waiting for TCPC in good condition. In group B, 6 patients underwent TCPC 8 +/- 7 months after BDG. One patient is awaiting TCPC and the remaining patient is considered unsuitable for TCPC. Cardiac catheterization performed in 32 patients showed significant decrease of pulmonary artery (Nakata) index from 307 +/- 73 to 215 +/- 45 mm2/m2 after BDG in group B (p < 0.05). On the other hand, the Nakata index stayed in higher range from 316 +/- 115 to 287 +/- 74 mm2/m2 in group A, and there was a significant correlation between the Nakata index and the percentage of its difference (Y = 40.823 - 0.144 X; n = 26, R = 0.740, p < 0.0001).

CONCLUSIONS

Appropriate additional pulmonary blood flow is useful for the completion of TCPC by means of suppressing the decrease in the size of the pulmonary artery, especially in patients with underdeveloped pulmonary arteries.

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.

Management of systemic venous anomalies in the pediatric cardiovascular surgical patient

Systemic venous anomalies are rare and heterogeneous entities. Although these anomalies are rare in the general population, they occur more frequently in the subpopulation with congenital heart disease. In and of themselves, most of these lesions have no physiologic significance. However, in the setting of congenital heart disease these lesions may significantly alter surgical treatment. This review is dedicated to these lesions.

Pulmonary artery growth fails to match the increase in body surface area after the Fontan operation

OBJECTIVE

To evaluate the growth of the pulmonary arteries after a Fontan procedure.

DESIGN

Retrospective review.

SETTING

Two paediatric cardiology tertiary care centres.

PATIENTS

61 children who underwent a modified Fontan operation and had angiography suitable for assessment of pulmonary artery size before the Fontan procedure and during long term follow up. An atriopulmonary connection (APC) was present in 23 patients (37.7%) and a total cavopulmonary connection (TCPC) was present in 38 (62.3%). Postoperative angiograms were performed 0.5-121 months (median 19 months) after the Fontan operation.

MAIN OUTCOME MEASURE

Growth of each pulmonary artery measured just before the first branching point. The diameter was expressed as a z score with established nomograms used to standardise for body surface area.

RESULTS

The mean change in the preoperative to postoperative z scores of the right pulmonary artery was -1.06 (p = 0.004). The mean change in the preoperative to postoperative z scores of the left pulmonary artery was -0.88 (p = 0.003). Changes in the preoperative to postoperative z scores were more pronounced in the patients undergoing APC than TCPC, especially for the right pulmonary artery.

CONCLUSION

After the Fontan operation, growth of the pulmonary arteries often fails to match the increase in body surface area.

Additional Pulmonary Blood Flow Has No Adverse Effect on Outcome After Bidirectional Cavopulmonary Anastomosis

BACKGROUND

Controversy continues over whether additional sources of pulmonary blood flow are beneficial in combination with a bidirectional cavopulmonary anastomosis. We have therefore assessed the effects of additional pulmonary blood flow on outcome after bidirectional cavopulmonary anastomosis.

METHODS

From 1996 to 2000, 106 patients underwent bidirectional cavopulmonary anastomosis, either isolated (group 1, n = 54), or with additional pulmonary blood flow through the pulmonary artery (group 2, n = 30) or a Blalock-Taussig shunt (group 3, n = 22).

RESULTS

Superior vena cava syndrome was more frequent in group 2 and less in groups 1 and 3 (p < 0.05). Low-output syndrome was more frequent in group 2 and less in group 3 (p = 0.01). Repeated-measures analysis of variance showed higher oxygen saturations with additional pulmonary blood flow (p < 0.05) and significant changes over time (p < 0.0001). Pulmonary pressures, systemic ventricular fractional shortening, end-diastolic diameter index, end-diastolic pressure, and atrioventricular valve regurgitation remained unaffected by additional pulmonary blood flow. Pulmonary artery pressures were lower in group 2 than 3 (p < 0.05). Fractional shortening (p < 0.05) and atrioventricular valve regurgitation (p < 0.0001) changed significantly over time. Fractional shortening showed a strong trend toward different changing patterns with or without additional pulmonary blood flow (p = 0.055), and atrioventricular valve regurgitation showed different changing patterns among the groups (p < 0.005). End-diastolic diameter and pulmonary artery dimensions, which were smaller than normal, remained unchanged. In logistic regression, smaller body surface area at bidirectional cavopulmonary anastomosis, single ventricle, and bidirectional cavopulmonary anastomosis with a Blalock-Taussig shunt were associated with early death. Actuarial survival including total cavopulmonary connection did not differ among groups (p = 0.96).

CONCLUSIONS

We conclude that additional pulmonary blood flow has no adverse effect on outcome after cavopulmonary anastomosis. Additional flow through the main pulmonary artery offers different advantages and disadvantages concerning perioperative complications and pulmonary artery growth compared with additional flow through a Blalock-Taussig shunt.

Effects of controlled antegrade pulmonary blood flow on cardiac function after bidirectional cavopulmonary anastomosis

BACKGROUND

Bidirectional cavopulmonary anastomosis (BCPA) has been used as an intermediate stage in the treatment of patients with single-ventricle physiology. Leaving additional antegrade pulmonary blood flow has been shown to improve postoperative arterial blood oxygen saturations; however, controversy continues over whether the potential increase in systemic venous pressure is detrimental. We studied the effects of controlled antegrade pulmonary blood flow on cardiac function in patients after BCPA.

METHODS

From January 1993 to July 2000, 128 patients underwent BCPA. Mean age at operation was 6.2 +/- 4 months (range 2 to 36 months). In group 1 (n = 72), restricted antegrade pulmonary blood flow was maintained through a native narrowed pulmonary valve or by adjustment of previously placed pulmonary artery band with the goal of maintaining the mean pulmonary artery pressure less than 16 mm Hg. In group 2 (n = 56), BCPA was the only source of pulmonary blood flow.

RESULTS

One hospital death (0.8%) occurred. The mean pulmonary artery pressure at the end of the operation was 13 +/- 2 mm Hg in group 1 compared with 12 +/- 2 mm Hg in group 2, a difference that was not significant. Patients in group 1 had higher arterial oxygen saturations (84% +/- 3% compared with 74% +/- 3% in group 2, p < 0.05), and shorter mean hospital stay (9 +/- 3 days compared with 15 +/- 2 days, p < 0.05). Persistent pleural effusion (> 10 days) or late chylothorax occurred in 4 patients from group 1 and 3 from group 2, a difference that was not significant. During a mean follow-up of 36 +/- 10 months no late deaths occurred. The mean oxygen saturation remained higher in group 1, 80% +/- 3% compared with 74% +/- 4% in group 2, and the hematocrit was lower, at 38% +/- 3% compared with 46% +/- 4% (p < 0.05 for both comparisons). Cardiac catheterizations were performed in 68 patients before completion Fontan. Total pulmonary artery (Nakata) index was 263 +/- 34 mm(2)/m(2) in group 1 (n = 40) and 188 +/- 13 mm(2)/m(2) in group 2 (n = 28) (p < 0.05). The mean pulmonary artery pressure and mean ventricular end-diastolic pressure were similar.

CONCLUSIONS

Controlled antegrade pulmonary blood flow may have favorable effects on cardiac function for a selected group of patients and does not appear to have adverse effects on subsequent suitability for completion Fontan.

Hypoventilation improves oxygenation after bidirectional superior cavopulmonary connection

OBJECTIVE

Bidirectional superior cavopulmonary connection may be complicated by systemic hypoxemia. Previous work has shown that hyperventilation worsens systemic oxygenation in patients after bidirectional superior cavopulmonary connection. The likely mechanism is that hyperventilation-induced hypocarbia decreases cerebral, superior vena caval, and pulmonary blood flow. The aim of the current study was to determine whether the converse approach, hypoventilation, improves oxygenation after bidirectional superior cavopulmonary connection.

METHODS

This is a prospective, patient-controlled study of 15 patients (median age 8.0 months, range 4.7-15.5) who underwent bidirectional superior cavopulmonary connection. Patients were studied in the intensive care unit, within 8 hours of surgery, while sedated, paralyzed, and mechanically ventilated. To avoid acidosis during hypoventilation, sodium bicarbonate was administered before hypoventilation. Cerebral blood flow velocity was measured by transcranial Doppler sonography of the middle cerebral artery.

RESULTS

Hypoventilation following administration of sodium bicarbonate (pH-buffered hypoventilation) produced hypercarbia (mean Pco(2) = 58 mm Hg versus 42 mm Hg at baseline). During hypoventilation, there were significant increases in both mean arterial Po(2) (from 50 mm Hg at baseline to 61 mm Hg; P <.05) and mean systemic oxygen saturation (from 86% at baseline to 90%; P <.05). These increases occurred despite accompanying, small increases in pulmonary artery pressure and transpulmonary gradient. Hypoventilation also produced an increase in mean cerebral blood flow velocity (from 37 cm/s at baseline to 55 cm/s; P <.05) and a decrease in the arteriovenous oxygen saturation difference across the upper body (from 33% at baseline to 23%; P <.05), consistent with increased cerebral blood flow.

CONCLUSIONS

This study demonstrates that hypoventilation improves systemic oxygenation in patients after bidirectional superior cavopulmonary connection. The likely mechanism for this effect is that hypoventilation-induced hypercarbia decreases cerebral vascular resistance, thus increasing cerebral, superior vena caval, and pulmonary blood flow. Hypoventilation may be a useful clinical strategy in patients who are hypoxemic in the early postoperative period after bidirectional superior cavopulmonary connection.

Single-ventricle physiology

The patient with single-ventricle physiology presents a significant challenge to the intensive care team at all stages of management. An integrated approach that applies a working knowledge of cardiac anatomy, cardiopulmonary physiology, and the basic principles of intensive care is essential to guide management for each individual patient. This management requires cooperative and constructive involvement of surgeons, cardiologists, and intensivists, as well as a nursing and respiratory care team experienced in the management of single-ventricle patients. The outcome of each stage of palliation for single-ventricle lesions should continue to improve as new ideas are developed and as older ideas are subjected to rigorous scientific analyses.

The ratio of flow in the superior and inferior caval veins after construction of a bidirectional cavopulmonary anastomosis in children

In patients who have undergone a superior cavopulmonary anastomosis, the superior caval venous flow provides the only, or the most important, pulmonary blood supply, while the inferior caval venous blood is not oxygenated, being mixed with the pulmonary venous blood before entering the systemic circulation. In healthy children, the contribution of superior caval venous flow to total cardiac output has been shown to decrease during growth. Patients who have undergone a superior cavopulmonary anastomosis, however, often have a higher oxygen saturation than predicted by the age-matched ratio of superior to inferior caval venous flows. This study was designed, therefore, to assess the ratio of flows in the superior and inferior caval veins subsequent to a superior cavopulmonary anastomosis. We carried out 18 magnetic resonance imaging studies with velocity-mapping and heart catheterisations so as to assess the contribution of superior caval venous flow to total cardiac output. Patients were divided into 3 groups according to their age. There were five aged from 8 to 24 months, eight aged from 24 to 48 months, and five older than 48 months. No significant difference could be found in the ratios of superior-to-inferior caval venous flow, nor of superior caval venous-to-systemic flow, between the 3 groups. The ratio of venous flows was 0.89 +/- 0.34 in those aged from 8 to 24 months, 1.09 +/- 0.42 in those from 24 to 48 months, and 1.25 +/- 0.27 in the older patients (F analysis of variance 1.06, p 0.37). The ratio of superior caval venous-to-systemic flow was 0.46 +/- 0.08 in the youngest patients, 0.50 +/- 0.09 in those aged from 24 to 48 months, and 0.55 +/- 0.05 in the older patients (F analysis of variance 0.76, p 0.49). These findings suggest that the hemodynamics of a cavopulmonary anastomosis may affect the normal decrease of superior caval venous flow with age. This could be related to a redistribution of flow, with a proportionally higher flow to the head and upper body after construction of a superior cavopulmonary anastomosis. Since increasing cyanosis and progressive exercise intolerance are the main indications for creation of a total cavopulmonary connection, these findings should be taken into account when determining the timing for completion of the Fontan circulation.

[The bidirectional Glenn operation in 100 cases with complex congenital heat diseases: factors influencing surgical results]

OBJECTIVE

The bidirectional Glenn shunt is a well established surgical technique in children with complex congenital heart disease. The present study is a retrospective analysis of patients undergoing this operation in order to assess the influence of different variables in the outcome.

PATIENTS AND METHOD

From December 1990 to June 2000, 100 patients received a bidirectional Glenn shunt. Two groups were defined, based on the outcome. Group A (n = 15, unsuccessfully result) including death and need to reoperate, and Group B (n = 85, patients with good outcome).

RESULTS

The mortality was 8%. Eight patients were reoperated at follow-up. The survivors were followed for a mean of 3.5 years. Mean pulmonary artery pressure 7 mmHg was a factor associated with poor clinical progress. Other variables (age less than 1 year, excessive pulmonary blood flow, double Glenn operation, significant anatomic anomalies, and arrythmias), were also associated with outcome. Significant variations were observed in the time of by-pass or the need for aortic clamp in cases with simultaneous operative repair of pulmonary branch stenosis. Actuarial survival rate, most more than 1 year was 92%, and freedom from reoperation at 3 years was 90%.

CONCLUSIONS

The bidirectional Glenn shunt is an excellent palliation in patients with functionally single ventricle. Mean pulmonary artery pressure was the most important variable related with the outcome. We are encouraged to continue with tendency to perform bidirectional Glenn shunt preferably early, avoiding, whenever possible, previous palliative surgery.

Bidirectional cavopulmonary shunt with right ventricular outflow patency: the impact of pulsatility on pulmonary endothelial function

OBJECTIVE

Although in vitro studies have suggested the importance of flow pulsatility in endothelial function, few reports have focused on pulmonary endothelial function under decreased pulsatile flow after a bidirectional cavopulmonary shunt with or without an additional pulmonary flow source. The purpose of the present study was to assess the pulmonary endothelial function after bidirectional cavopulmonary shunt.

METHODS AND RESULTS

Pulmonary vasodilating response was evaluated in 10 patients 0.4 to 7.0 years (median 1.6 years) after bidirectional cavopulmonary shunt who were provided an additional flow source by retaining the pulmonary outflow tract and in 8 control subjects. Average pulmonary flow velocity was measured with a Doppler flow wire placed in the segmental lower lobe pulmonary artery during incremental infusion of acetylcholine (10(-8), 10(-7), 10(-6), and 10(-5) mol/L) and then of nitroglycerin (0.5 and 1.0 microg. kg(-1). min(-1)) after recovery. In the control subjects, a dose-dependent increase in flow velocity was observed in response to acetylcholine (maximum increase was 155% +/- 17% of baseline) and to nitroglycerin (maximum increase was 151% +/- 20% of baseline). In contrast, patients showed a significantly impaired response to acetylcholine (maximum increase was 124% +/- 17% of baseline; P <.01 vs control), whereas the response to nitroglycerin was preserved (138% +/- 12% of baseline; P =.09 vs control). In addition, the maximum response to acetylcholine correlated significantly with the pulmonary pulse pressure (r = 0.89, P <.01) and with the pulmonary flow pulsatility (r = 0.88, P <.01).

CONCLUSIONS

These results clearly suggest that patients after bidirectional cavopulmonary shunt show pulmonary endothelial functional attenuation and, of more importance, that decreased pulsatility of cavopulmonary flow is mainly responsible for this endothelial abnormality.

Bidirectional Glenn procedure improves the mechanical efficiency of a total cavopulmonary connection in high-risk fontan candidates

BACKGROUND

A total cavopulmonary connection (TCPC) is a widely performed surgical procedure for Fontan candidates. High-risk candidates who have undergone the bidirectional Glenn procedure (BDG) before TCPC have shown good results. The exact mechanism of this procedure, however, is still poorly understood. We hypothesized that a volume reduction with BDG improved ventricular contractility, thereby optimizing mechanical efficiency after TCPC.

METHODS AND RESULTS

We measured percent normal systemic ventricular end-diastolic volume (%N-EDV), contractility (end-systolic elastance; E(es)), afterload (effective arterial elastance; E(a)), and mechanical efficiency (ventriculoarterial coupling; E(a)/E(es)) on the basis of the cardiac catheterization data before and after TCPC. Eighteen patients who underwent staged TCPC after BDG (staged group) were compared with 29 patients who underwent primary TCPC (primary group). E(es) and E(a) were approximated as follows: E(es)=mean arterial pressure/minimal ventricular volume, and E(a)=maximal ventricular pressure/(maximal ventricular volume-minimal ventricular volume), and E(a)/E(es) was then calculated. The ventricular volume was normalized with the body surface area. A canine experimental model with conductance catheter was used to validate the accuracy of this approximation of E(es) and E(a). %N-EDV decreased after TCPC in both groups. In the staged group, a smaller ventricular volume resulted in better contractility (E(es)). Although afterload (E(a)) increased in both groups, the increment of E(a) was smaller in the staged group. These changes resulted in an improvement of E(a)/E(es) in the staged group, whereas E(a)/E(es) increased in the primary group.

CONCLUSIONS

The volume reduction of BDG preceding TCPC allows for any afterload mismatch to be corrected, thereby improving ventricular energetics after TCPC.

Bi-directional cavopulmonary shunt: is accessory pulsatile flow, good or bad?

OBJECTIVE

Evaluation of the effect and long-term outcome of accessory pulsatile blood flow versus classical bi-directional cavopulmonary connection (BCPC).

METHODS

Retrospective review of the medical and surgical records.

RESULTS

Two-hundred and five patients (119 boys, 86 girls) underwent BCPC from 1990 to 1996. Accessory pulsatile flow was present in 68%, flow being maintained through the pulmonary trunc in 46%, systemic-to-pulmonary artery shunt in 13% and mixed in 7%, or patent ductus arteriosus in 2%. Patients with accessory pulsatile flow had lower hospital mortality (3% versus 5%), while mean pulmonary artery pressure (14.1 versus 12.6 mmHg P = 0.050) and increase of oxygen saturation (12.4 versus 8.7, P = 0.034) were significantly higher. The period of artificial ventilation (1.9 day) and ICU stay (6 days) did not differ for both groups. Late mortality was higher following accessory pulsatile flow (6% versus 1%). At late follow-up patients with accessory pulsatile flow had significantly higher oxygen saturation (mean 85 +/- 4%, versus 79 +/- 4%; P < or = 0.005). If subsequent completion of Fontan is considered the optimal palliation and subsequent systemic to pulmonary artery shunt, arteriovenous fistula and transplantation is considered a failure, patients with accessory pulsatile flow had significantly more and earlier completion of the Fontan procedure (mean 1.7 +/- 2.4 years, versus 2.7 +/- 4.4 years; P = 0.008). Survival is not influenced by age at bi-directional cavopulmonary shunt surgery, left or right functional ventricular anatomy or previous palliative surgery. One patient with accessory pulsatile flow developed systemic-to-pulmonary collateral's eventually requiring lobectomy.

CONCLUSION

Despite two different initial palliative techniques the outcome was not significantly different. Accessory pulsatile blood flow appeared not to be a contra-indication for a completion Fontan procedure. Moreover, the data suggest that after accessory pulsatile flow can safely be performed, at late follow-up oxygen saturation is higher, while, significantly more and earlier completion of Fontan occurred. Age at bi-directional cavopulmonary shunt, basic left or right ventricular anatomy or previous palliative surgery did not influence survival.

Bubble contrast echocardiography in detecting pulmonary arteriovenous shunting in children with univentricular heart after cavopulmonary anastomosis

OBJECTIVES

We sought to compare bubble contrast echocardiography and pulmonary angiography in detecting pulmonary arteriovenous malformation (PAVM) in children with cavopulmonary anastomosis (CPA), and to examine anatomic and physiologic variables associated with the development of PAVM.

BACKGROUND

Development of PAVM in patients with CPA may cause profound cyanosis. Pulmonary arteriovenous malformation has been traditionally diagnosed by pulmonary angiography with reported incidence of 20% to 25% in patients with CPA.

METHODS

Fourteen patients (age 1.1 to 12.6 years) with any forms of CPA and normal pulmonary venous drainage formed the study population. All patients underwent cardiac catheterization and pulmonary angiography. Bubble contrast echocardiographic studies were performed with injection of 10 ml of agitated saline solution into branch pulmonary arteries. Transthoracic echocardiograms using an apical view were performed to assess the appearance of bubble contrast in the systemic ventricles. We compared the results of pulmonary angiograms and contrast echocardiograms, and findings of contrast echocardiograms between lungs with hepatic venous blood flow and lungs without hepatic venous blood.

RESULTS

Ten of the 14 patients (71%) had positive contrast echocardiographic studies, compared with three (21%) detected by pulmonary angiograms (p = 0.01). No difference was found in pulmonary artery pressure, transpulmonary gradient or presence of heterotaxy syndrome between patients with positive contrast echocardiographic studies and patients with negative studies. However, patients with positive contrast echocardiograms tended to have lower oxygen saturation (81%) and higher hemoglobin (16.4 g/dl) compared with patients with negative studies (88% and 14.7 g/dl, p = 0.10 and p = 0.18 respectively). Patients with Glenn shunt or unidirectional Fontan had higher incidence of PAVM (10/11) compared with patients with classic or lateral tunnel Fontan (0/3, p = 0.01). All 12 lungs with no perfusion of hepatic venous blood had positive contrast echocardiographic studies. Lungs with no hepatic venous blood flow were more likely to develop PAVM compared with lungs with hepatic venous blood flow (12/12 and 3/16 respectively, p < 0.01).

CONCLUSIONS

Bubble contrast echocardiography is more sensitive in detecting PAVM compared with pulmonary angiography. The prevalence of PAVM in patients with CPA may be much higher than what had been reported previously. Lungs with no hepatic venous blood flow are more likely to develop PAVM than lungs with hepatic venous blood flow.

Experience with the Glenn anastomosis in the adult with cyanotic congenital heart disease

A clinical study on the outcomes of Glenn anastomoses performed since 1987 in eight consecutive patients aged > or = 16 years, and in two performed earlier, showed poor results. One badly selected patient died early as a consequence of high venous pressure, while a further seven had early complications. Seven of eight hospital survivors were followed for 1-10 (median 4.2) years with two deaths (1 and 4 years later). Of the remaining five patients, two improved temporarily, but increased arterial oxygen saturation was not maintained after 6 months. The two patients who had undergone a Glenn anastomosis 10 and 34 years earlier were shown to have pulmonary arteriovenous fistulas. The Glenn anastomosis in these older patients is associated with high rates of complication and appears not to give adequate palliation, particularly when it is the only source of pulmonary blood supply. In the adult, the Glenn anastomosis can be used as a staging procedure for Fontan-type surgery, but must be combined with another source of pulmonary arterial supply. Any adult having a Glenn anastomosis, particularly without another source of pulmonary arterial supply, should be warned of the possibility of worsening of cyanosis and symptoms. The second stage of the procedure may need to be performed soon after the first should the hypoxia prove intolerable.

Recent advances in the surgical management of the single ventricle pediatric patient

A standardized approach to the patient with single ventricle anatomy (SVA) is presented in this article. Regardless of the specific anatomic subtype, patients with SVA share common risk factors for early and late mortality and morbidity. Management of the SVA patients requires a plan to avoid development of these risk factors. Neonatal palliation is directed at relieving any systemic obstruction and appropriate limitation of pulmonary blood flow. The application of a standardized approach to the neonate with SVA, followed by staged palliation to a completion Fontan procedure should result in improved early and late outcome.