Additional Pulmonary Blood Flow Research Articles

Glenn bidireccional: resultados y análisis de factores de riesgo en una experiencia de 5 años

Bidirectional Glenn shunt is a palliative surgical procedure in patients with single ventricle. Although morbimortality in this surgery is low, risk factors have been described. The purpose of this study is to report our outcomes in Glenn surgery, identifying mortality risk factors in our population. Retrospective study between 2005 and 2009. Age, weight, previous surgery, surgical procedure, and postoperative condition were analyzed. Results are reported as median and rank, or absolute values and percentage. Uni and multivariate analysis was made to identify risk factors of mortality and/or prolonged hospitalization (Stata 9.0). One hundred and one patients were operated; 87 bidirectional Glenn and 14 bilateral Glenn. Median age 15 months (2.5-108), median weight 8.5 kg (4.2-27), and 74% of them with previous surgery. In 54 patients an associated procedure was performed simultaneously, only in 4 additional pulmonary blood flow was left. Median hospitalization was 8 days (2-97). Thirty-five percent of the patients presented complications. No association between age, weight, pulmonary hypertension, cardiopulmonary bypass, cross clamping, associated procedures or Glenn bilateral with mortality or morbidity was found. Overall mortality was 3.9%. Mortality was similar to other centers, but morbidity in this group of patients is high. No independent risk factors associated with morbidity or mortality were identified.

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

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. 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. 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. 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.

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

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. 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. 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. 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.

Invited Commentary

Invited Commentary

Quantification of Ventricular Volume Load in the Context of a Bidirectional Cavopulmonary Shunt: A Theoretical Treatise

Functional univentricular hearts are currently palliated by a staged procedure of which the bidirectional cavopulmonary shunt is usually the second stage. In addition to this stage, a calibrated amount of additional pulmonary blood flow may be preserved to promote pulmonary artery growth and increase the length of the interval preceding the total cavopulmonary connection. However, additional pulmonary blood flow can be deleterious for ventricular functioning and development as it increases functional ventricular volume load. Using the Fick principle we devised a theoretic framework to estimate the ventricular volume loading caused by additional pulmonary and collateral aortopulmonary flow. To use this framework, blood samples need to be taken intraoperatively from the aorta, pulmonary veins, and inferior caval vein to determine oxygen saturations. The oxygen saturation samples have to be taken sequentially with and without additional pulmonary blood flow. The objective of this paper is to provide a theoretic framework to estimate the ventricular volume loading caused by collateral aortopulmonary flow and additional pulmonary blood flow in the context of a bidirectional cavopulmonary shunt in the staged palliation of univentricular hemodynamics. The formulas have not yet systematically been applied in vivo. The added volume loading of the ventricle caused by additional pulmonary blood flow can theoretically be estimated using the newly devised formulas so as to calibrate ventricular volume loading to a desired level intraoperatively.

The Effect of Additional Pulmonary Blood Flow on Timing of the Total Cavopulmonary Connection

The staged Fontan procedure is used to palliate functionally univentricular hearts. The effect of additional pulmonary blood flow combined with a bidirectional cavopulmonary shunt in these patients remains a controversial subject. This retrospective study included all 82 patients with a unilateral or bilateral bidirectional cavopulmonary shunt at our institution between April 1990 and July 2010. Patients with hypoplastic left heart syndrome were excluded. Two groups, based on the presence (n=57) or absence (n=25) of additional pulmonary blood flow after the bidirectional cavopulmonary shunt, were compared. Patients with a bidirectional cavopulmonary shunt combined with additional pulmonary blood flow had higher arterial oxygen saturations postoperatively (86% [interquartile range, 85% to 90%] vs 82% [80% to 85%]; p=0.001) and had a longer median interval before the total cavopulmonary connection (3.42 [2.43 to 4.89] years vs 2.90 [2.08 to 3.32] years; p=0.06). At the total cavopulmonary connection, they were older (4.59 [3.88 to 6.49] years vs 3.94 [3.10 to 4.57] years; p=0.03) and had a larger median body surface area (0.73 [0.65 to 0.87] m2 vs 0.68 [0.59 to 0.73] m2; p=0.04). Patients with a bidirectional cavopulmonary shunt and additional pulmonary blood flow have a longer interval before the total cavopulmonary connection without evident untoward effects. This may theoretically be advantageous for the pulmonary artery growth needed for a successful Fontan circulation. Furthermore, postponement of the final Fontan may ensure the insertion of a larger extracardiac conduit to avoid prosthesis-patient mismatch.

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

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. 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. 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. 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.

Unusual cause of neonatal cyanosis

We present a case of a full-term female neonate who presented at 6 h of age with severe cyanosis and was partially responsive to oxygen supplementation. An echocardiogram showed an isolated congenital severe tricuspid valve insufficiency due to rupture of the papillary muscle of the anterior tricuspid valve leaflet. Magnesium sulfate was infused to lower the pulmonary resistance and thus enhancing the antegrade pulmonary blood flow. Ductal patency was secured by prostaglandin infusion thus providing an additional pulmonary blood flow through the ductus arteriosus. The above measures were adequate to stabilize the patient with no further deterioration or the need for other supportive measures such as Nitric Oxide therapy or extracorporeal membrane oxygenation (ECMO). Therefore, early diagnosis and adequate measures to improve the pulmonary blood flow are mandatory, important pre-operative measures in the management of these patients.

Increasing the accuracy of lung perfusion scintigraphy in children with bidirectional Glenn circulation

In children who have undergone a bidirectional Glenn procedure without antegrade or additional pulmonary blood flow, we have often noted a discrepancy between apparent lung perfusion on scintigraphy and superior vena cava angiography when evaluating right and left pulmonary blood flow. We found a tendency for radionuclide, tracer 99mTc-MAA, when administered through a single upper extremity vein, to preferentially accumulate in the ipsilateral lung. In the present study, we examined whether the ratio of right-to-left pulmonary flow varied when 99mTc-MAA was administered via either the right upper or the left upper extremity vein. We studied six children (median age 1.3 ± 0.23 years) who underwent a bidirectional Glenn before total cavopulmonary connection. Five children who underwent biventricular repair served as a control. Perfusion scintigraphy using 99mTc-labeled macroaggregated albumin (99mTc-MAA) was performed in all children. First, we injected radionuclide via the right upper extremity and calculated the pulmonary accumulation in both lungs (R-image). Second, we injected the same dose of radionuclide via the left upper extremity and calculated the pulmonary accumulation (B-image), which represented the resulting administration via both upper extremities. The lung accumulation that resulted from radionuclide administration via the left upper extremity (L-image) was determined by subtracting the R-image from the B-image. We evaluated the right-to-total pulmonary blood flow ratio (radionuclide accumulation in right lung / radionuclide accumulation in both lungs) in the R-, L- and B-images. The right-to-total pulmonary blood flow ratios in the R-, L- and B-images were 815 ± 15.3%, 39.8 ± 11.7% and 61.3 ± 11.8%, respectively, and there were significant differences among the three images (P < 0.01). On the other hand, in the control group, the right-to-total pulmonary blood flow ratios in the R-, L- and B-images were 59.3 ± 22.4%, 57.8 ± 26.4% and 58.8 ± 23.7%, respectively, and there was no significant difference. In children with bidirectional Glenn circulation without antegrade or additional pulmonary blood flow, the venous blood of each arm tends to flow into the ipsilateral lung. The administration of radionuclide via both arms is important for accurate evaluation of lung perfusion scintigraphy in children who have undergone a bidirectional Glenn procedure.

Bidirectional Cavopulmonary Shunt with Additional Pulmonary Blood Flow

There are some controversies regarding the usefulness of leaving additional pulmonary blood flow when establishing a bidirectional cavopulmonary shunt. From April 2002 to September 2008, 13 patients (mean age, 24 +/- 16 months) underwent a bidirectional cavopulmonary shunt procedure with fine adjustment of additional pulmonary blood flow, as an intermediate step before the Fontan operation. There were no hospital deaths. Modified Blalock-Taussig shunts were left during the bidirectional cavopulmonary shunt operation in 7 patients, and pulmonary bands were tightened in 4. The main pulmonary artery with a previous pulmonary band was left open in one case. Oxygen saturation increased from 74.5% +/- 7.4% to 84.6% +/- 1.9% after the operation, cardiothoracic ratio decreased from 55.9% +/- 6.1% to 53.2% +/- 3.4%, Left ventricular end-diastolic pressure decreased from 11.0 +/- 2.6 to 7.8 +/- 3.0 mm Hg, and mean pulmonary arterial pressure from 14.7 +/- 7.5 to 10.2 +/- 3.1 mm Hg. Pulmonary artery index did not change significantly. In our experience, additional pulmonary blood flow with adjustment in each patient at the time of shunt construction was an excellent temporary palliation prior to the Fontan operation.

Preoperative evaluation of candidates for total cavopulmonary connection: The role of echocardiography and cardiac catheterization

To evaluate the information provided by echocardiography and cardiac catheterization in patients with partial cavopulmonary connection (PCPC) with or without additional pulmonary blood flow (PBF) in whom total cavopulmonary connection (TCPC) was planned. We retrospectively evaluated the results provided by echocardiography and cardiac catheterization in 110 consecutive patients with PCPC (35 with isolated PCPC, 38 with associated antegrade PBF, 37 with associated retrograde PBF) in whom TCPC was planned. Eight patients had superior vena cava syndrome; all others suffered from cyanosis and fatigue. Pulmonary artery size could be determined in 54% of patients without additional PBF, in 47% of those with associated retrograde PBF and in 68% of those with associated PBF (p=0.20). Concomitant clinical signs of increased central venous pressure and echocardiographic signs of ventricular dysfunction and/or hypoplastic pulmonary arteries identified four patients in whom TCPC was not low-risk. PAP exceeding 16 mmHg was found in 9% of patients without and 16% of those with associated PBF (p=0.38). The Nakata index was higher in patients with associated antegrade PBF than in those without associated PBF (p=0.004) or in those with associated retrograde PBF (p=0.002). Of the 16 patients who needed concomitant interventional catheterization, 10 had associated retrograde PBF (p<0.05). In 11 patients (nine with and two without additional PBF), TCPC was contraindicated. Cardiac catheterization is still necessary before TCPC, mostly in patients with additional PBF, to identify those at risk and those needing interventional catheterization.

Superior vena cava syndrome after pulsatile bidirectional Glenn shunt procedure: Perioperative implications

Bidirectional superior cavopulmonary shunt (bidirectional Glenn shunt) is generally performed in many congenital cardiac anomalies where complete two ventricle circulations cannot be easily achieved. The advantages of BDG shunt are achieved by partially separating the pulmonary and systemic venous circuits, and include reduced ventricular preload and long-term preservation of myocardium. The benefits of additional pulsatile pulmonary blood flow include the potential growth of pulmonary arteries, possible improvement in arterial oxygen saturation, and possible prevention of development of pulmonary arteriovenous malformations. However, increase in the systemic venous pressure after BDG with additional pulsatile blood flow is known. We describe the peri-operative implications of severe flow reversal in the superior vena cava after pulsatile BDG shunt construction in a child who presented for surgical interruption of the main pulmonary artery.

Bidirectional cavopulmonary connection without additional pulmonary blood flow in patients below the age of 6 months☆

The bidirectional cavopulmonary connection (BCPC) has shown excellent results as an intermediate step towards permanent palliation in functional single ventricle morphology. The optimal timing of the BCPC, though, remains unclear. This investigation focuses on results in a subgroup of patients under 6 months of age. Between 2001 and 2006, 124 patients received a BCPC followed by an extracardiac total cavopulmonary connection (TCPC). Review of 84 angiograms before BCPC and before TCPC allowed for analysis of haemodynamic findings and measurement of the diameters of the pulmonary arteries. Twenty-eight patients were below 6 months of age at the time of BCPC (group 1), whereas 56 were above 6 months of age (group 2). Age at time of BCPC was 4.6+/-1 months (range 2-6 months) for group 1, compared to 16.6+/-17 months (range 6-98 months) for group 2 (p<0.001). The most common diagnosis was a hypoplastic left heart syndrome (HLHS) in 16 patients (19%). The rate of patients with HLHS was higher in group 1 than in group 2 (p=0.006). There was a significant increase in oxygen saturation from 73+/-11% prior BCPC to 83+/-6% prior to TCPC in group 1 (p=0.001) and from 75+/-8% to 83+/-6% in group 2 (p=0.003) respectively. The mean pulmonary artery pressure decreased from 18+/-10 mmHg before BCPC to 9+/-2 mmHg before TCPC in group 1 (p<0.001) and from 14+/-7 mmHg to 8+/-3 mmHg in group 2 (p=0.001). The pulmonary artery diameters increased in both groups between BCPC and TCPC, except for the left pulmonary artery in group 2. Nevertheless, the pulmonary arteries remained too small for the given body surface area. Early unloading of the functional univentricular heart by means of BCPC without additional pulmonary blood flow is feasible even in very young patients. Favourable haemodynamics and reasonable increase in pulmonary artery size allow for good condition prior to completion to TCPC.

Bidirectional cavopulmonary connection without additional pulmonary blood flow as an ideal staging for functional univentricular hearts☆

Our institutional policy differs from others substantially, as we never leave any additional blood flow at the time of performing bidirectional cavopulmonary connection (BCPC). The aim was to evaluate the influence of this strategy on hemodynamics and pulmonary artery development. Between 2001 and 2006 a total of 124 patients had completion to a total cavopulmonary connection (TCPC). Review of 84 angiograms before BCPC and TCPC allowed for analysis of hemodynamic findings and measurement of the pulmonary arteries (PA). Mean age at BCPC was 12.6+/-15.3 months. Mean age at time of TCPC was 31.3+/-18.7 months, with an interval of 18.6+/-11.8 months between BCPC and completion to extracardiac TCPC. There was no postoperative mortality after BCPC, one patient died after TCPC (1.2%). The mean oxygen saturation increased after BCPC from 74.4% to 79.6% (p<0.01). The mean PA pressures decreased after BCPC from 15.1 to 13.5mmHg (n.s.). The mean left atrial pressure decreased from 5.8 to 4.9mmHg prior to TCPC (p=0.06). The pulmonary/systemic blood flow ratio was 1.4 prior to BCPC and decreased to 0.67 prior to TCPC (p=0.04). The pulmonary/systemic resistance ratio decreased also from 0.19 to 0.07 prior to TCPC (p<0.01). The right PA, as well as the right lower lobe PA, showed a significant increase in diameter after BCPC (p<0.01). The left PA also increased in size, although this was not statistically significant. After BCPC without additional blood flow, hemodynamic findings are favorable for completion of TCPC. Our findings support our institutional policy not only for an early staging to a BCPC, but likewise a swift completion towards a TCPC.

Bidirectional Glenn and Antegrade Pulmonary Blood Flow: Temporary or Definitive Palliation?

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

Nonfenestrated Extracardiac Total Cavopulmonary Connection in 132 Consecutive Patients

The study was conducted to assess the need for fenestration for completion of a total cavopulmonary connection (TCPC) with the most recent modification of an extracardiac conduit. The extracardiac approach was introduced to our institution in January 1999. Between June 2000 and June 2006, 132 consecutive patients were treated without a fenestration. At the time of TCPC, the median age was 31 months (range, 16 251), with 93 patients (70%) being younger than 48 months. Median patient weight was 12.5 kg (range, 9 to 66 kg). A previous partial cavopulmonary connection (PCPC) was accomplished in 117 patients (88.6%), without additional pulmonary blood flow. Thirty-day-mortality was 1.5%. Median time to extubation was 14 hours (range, 3 hours to 126 days). Initial pulmonary artery pressure value was 16.5 +/- 2.2 mm Hg, and 13.1 +/- 1.8 after extubation. Median drainage requirement was 4 days (range, 1 to 45), and median duration of hospitalization was 20 days (range, 5 to 128). Thirty-one (24%) required repeat drainage insertion. No subsequent fenestration was performed, and at hospital discharge no significant repeat effusions were observed. Multiple covariate logistic regression revealed longer time interval from PCPC to extracardiac TCPC (p = 0.006) as a significant predictor of pleural drainage lasting longer than 4 days, and older age at the time of extracardiac TCPC (p = 0.040) as a risk factor for hospitalization more than 20 days. Higher pulmonary artery pressure 3 hours postoperatively was a significant predictor for both outcome variables in the multivariate model (p = 0.013, p = 0.001). In general, an extracardiac TCPC can be performed without fenestration. Early staging of patients with functional single ventricle physiology may be one of the keys for these findings.

Invited commentary

The article by Yoshida and colleagues [1Yoshida M. Yamaguchi M. Yoshimura N. et al.Appropriate additional pulmonary blood flow at the bidirectional Glenn procedure is useful for completion of total cavopulmonary connection.Ann Thorac Surg. 2005; 80: 976-981Abstract Full Text Full Text PDF PubMed Scopus (54) Google Scholar] is useful for completion of the total cavopulmonary connection” reminds us once again of the controversy involving the influence of additional pulsatile pulmonary artery blood flow in conjunction with the construction of the bidirectional cavopulmonary shunt as an intermediate step toward completion of the Fontan procedure (total cavopulmonary connection) in correction of single ventricle physiology. There has been much discussion and disagreement concerning ventricular volume and unloading, pulmonary artery growth or lack of growth, particularly in the contralateral pulmonary artery, central venous pressure, pulmonary artery pressure and resistance, systemic oxygen saturations (both early and late), and post-procedure morbidity and mortality. Yet no clear conclusions can be drawn about the usefulness of additional pulmonary blood flow and what remains at the heart of the issue. Of particular and singular importance is simply this: Does additional pulmonary blood flow influence the final outcome by ensuring that the greatest number of candidates will progress to successful outcome after the final stage of the modified Fontan procedure? Yoshida and colleagues have attempted to convince us that it does. However, I do not believe that the authors have proven their hypothesis. They have eloquently demonstrated a suppression of pulmonary artery growth retardation, particularly for those patients with small pulmonary arteries when additional “regulated” pulmonary blood flow is provided along with the bidirectional cavopulmonary shunt. What they have not demonstrated effectively is that it has made any difference in the clinical outcome leading to and after completion of the Fontan procedure, except that the final stage needed to be carried out sooner when additional pulsatile pulmonary artery blood flow was not provided. As the authors point out so clearly, this study is not randomized, the numbers are small, and the two groups are not totally equal, leaving us with yet another study that can not answer the definitive question definitively.

Appropriate Additional Pulmonary Blood Flow at the Bidirectional Glenn Procedure is Useful for Completion of Total Cavopulmonary Connection

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. 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. 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). 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.

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

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. 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). 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). 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.

INVITED COMMENTARY

Berdat and coworkers have supplied one of the most suggestive contributions to the thesis that additional pulmonary blood flow, while providing higher oxygen saturation, has no adverse effect on clinical and functional outcome after cavopulmonary anastomosis. For the sake of discussion, however, I should raise some observations. First, this is not a prospective randomized study, and the three groups of patients considered are not totally comparable, particularly in terms of age at surgery. Second, some of the findings are contradictory or unexpected.