Major Aortopulmonary Collateral Arteries Research Articles

Pregnancy in non-palliated functionally single ventricle: challenges of management in resource-poor settings

Women with complex functionally univentricular hearts rarely survive into adulthood without corrective or palliative surgery. Reports of pregnancy outcome in this group of patients in resource-poor settings are sparse. We report a case of unrepaired pulmonary atresia ventricular septal defect (VSD) with major aorto-pulmonary collateral arteries (MAPCA) who survived into adulthood and was able to complete a successful pregnancy in a resource-poor country.

Comparison of computed tomography angiography versus cardiac catheterization for preoperative evaluation of major aortopulmonary collateral arteries in pulmonary atresia with ventricular septal defect.

Introduction:Pulmonary atresia with the ventricular septal defect is a rare congenital heart defect with high anatomic variability. The most important management question relates to the sources of pulmonary blood flow. The ability to differentiate between ductal dependence and major aortopulmonary collateral arteries is critical to achieving good outcomes and avoiding life-threatening hypoxia in the postneonatal period. Having accurate information about pulmonary arteries, major aortopulmonary collateral arteries, and sources of blood supply to each pulmonary segment is crucial for choosing the optimal surgical strategy. The purpose of this study is to compare computed tomography angiography (CTA) with cardiac catheterization for anatomic delineation of surgically relevant anatomy in pulmonary atresia with ventricular septal defect with major aortopulmonary collateral arteries.Materials and Methods:Retrospective review of all children with pulmonary atresia with ventricular septal defect with major aortopulmonary collateral arteries cared for at a large tertiary children's hospital who underwent cardiac catheterization with angiography and CTA close to each other without interval therapy. All studies were performed between 2007 and 2011.Results:There were 9 patients who met the inclusion criteria. Pulmonary artery anatomy (confluent vs. nonconfluent) was correctly identified in 9 patients by CTA and 8 patients by catheterization. There were no significant differences between CTA and catheterization in the identification of major aortopulmonary collateral arteries (mean = 3.4 collaterals/study via catheterization; mean = 3.1 collaterals/study via CTA; P = 0.67). CTA was superior to catheterization in the delineation of segmental pulmonary blood flow (P = 0.006).Conclusion:CTA and catheterization are equivalent in their ability to delineate pulmonary artery anatomy and major aortopulmonary collateral arteries.

Morphological and clinical indices determining mode of repair in children with tetralogy of Fallot in Enugu, Nigeria

Background: Children with tetralogy of Fallot (TOF) present with various clinical and morphological attributes which aid in screening for primary, stage, or elective repair. Objectives: This study is aimed at determining the morphological and clinical indices that predict mode of repair among children with TOF in our locale. Materials and Methods: This was a retrospective echocardiographic review of children with TOF carried out in three different institutions over a 5-year period. Results: The mean age of presentation was 5.0 ± 5.3 years. The nutritional status revealed that 18.2% (8/44) were wasted, 25.0% had severe wasting, while 2.3% were obese. Stunting was observed in 4.5% of the patients and severe stunting in 29.5%. The mean pulmonary valve (PV) annulus of 43 of the patients assessed was 11.0 ± 5.5 mm (mean z-score: −2.03 ± 1.95). Five of them (11.6%) had values one standard deviation (1SD) below the mean of the standard population, 32.6% had values 2SD below the mean, and 27.9% had values 3SD below the mean. Of the 33 children whose right pulmonary artery (RPA) z-scores were assessed, 24.2%, 12.1%, and 12.1%, respectively, had RPA z-scores of 1SD, 2SD, and 3SD below the mean of the standard population, while 17.5% and 7.5% of 40 children whose left pulmonary arteries were assessed had z-scores of 1SD and 2SD below the standard mean, respectively. Right aortic arch and major aortopulmonary collateral arteries (MAPCAs) were seen in 8.1% and 30.5% of the children, respectively. 30.5% of the children with TOF had MAPCAs. Features of Down syndrome were observed in 4.8% (3/62) of the patients. Conclusion: A large proportion of patients present with various degrees of malnutrition with a significant low z-score for PV annulus and branch pulmonary artery diameters. The presence of right aortic arch and MAPCAs was observed in the patients. The increased rate of protein–energy malnutrition, small PV annulus, MAPCAs and presence of right aortic arch, etc., are screening tools that may assist the surgeon in selecting the various surgical options and timing in the approach of children with TOF in this locale.

Anesthetic management in tetralogy of fallot with pulmonary atresia and major aortopulmonary collateral arteries in pediatric patients: One year experience.

Background:Unlike the typical tetralogy of fallot (TOF), the presence of pulmonary atresia and major aortopulmonary collaterals is recognized as a rare but severe variant of TOF. The objective was to describe the perioperative anesthetic management of pediatric patients who underwent unifocalization procedure and to describe their postoperative morbidity and mortality.Methods:A retrospective observational study was conducted among pediatric patients who underwent unifocalization procedure at Prince Sultan Cardiac Center (PSCC) between October 2017 and October 2018. Unifocalization procedures were performed in a two-staged approach. Anesthetic management of both stages had similar concerns and challenges but with few peculiar issues. These included preoperative assessment, intraoperative management, vascular access, positioning, ventilation, optimizing hemodynamics, cardiopulmonary bypass monitoring, and postoperative management.Results:A total of 19 unifocalization procedures were included. The average age was one year and 52.6% were females. Two patients (10.5%) arrived in theater already with intubated ventilation. Continuous mandatory ventilation was used in 11 (57.9%) patients while one-lung ventilation was used in the rest of patients. Approximately, 30% of patients encountered a stormy postoperative course, 52.6% underwent cardiopulmonary bypass with or without cross-clamping of the aorta, and 10.5% had reperfusion injury.Conclusions:Despite the major challenges of unifocalization, significantly low rates of morbidity and mortality were observed in our patients. A thorough familiarity of different airway and ventilation issues, besides meticulous hemodynamic and anesthetic management, is of paramount importance. The maintenance of hemodynamic stability, hemostasis, and proper ventilation is critical for the success of the operation.

Pulmonary atresia with ventricular septal defect and major aorto-pulmonary collateral arteries in a young adult

Pulmonary atresia with ventricular septal defect and major aorto-pulmonary collateral arteries in a young adult

Surgical Strategies and Results for Repair of Pulmonary Atresia with Ventricular Septal Defect and Major Aortopulmonary Collaterals: Experience of a Single Tertiary Center.

ObjectiveTo evaluate surgical management and results of patients with pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries (PA/VSD/MAPCAs).MethodsWe reviewed a consecutive series of patients with PA/VSD/MAPCAs between January 2012 and October 2018. Study patients were separated into Group A, efficient MAPCAs; Group B, hypoplastic MAPCAs; Group C, severe hypoplastic MAPCAs at all divisions; and Group D, distal stenosis at most MAPCAs divisions.ResultsThirty-six patients were included in the study. Median age at operation time was 5.5 months (2-110 months), median weight was 8 kg (2.5-21 kg), and median number of MAPCAs was three (1-6). In Group A, 14 patients underwent single-stage total correction (TC); in Group B, 18 patients underwent unifocalization and central shunting; and in Group C, four patients had aortopulmonary window creation and collateral ligation. No patient was placed in Group D. Seventy percent of patients (n=25) had the TC operation. Early mortality was not seen in Group A, but the other two groups had a 13.6% mortality rate. At the follow-up, three patients had reintervention, two had new conduit replacement, and one had right ventricular outflow tract reconstruction.ConclusionEvaluating patients with PA/VSD/MAPCAs in detail and subdividing them is quite useful in determining the appropriate surgical approach. With this strategy, TC can be achieved in most patients. Single-stage TC is better than other surgical methods due to its lower mortality and reintervention rates. Care should be taken in terms of early postoperative intensive care complications and reintervention indications during follow-ups.

Staged Treatment Using Right Ventricular Outflow Tract Stenting for Effective Augmentation of Native Pulmonary Arteries in a Case of Tetralogy of Fallot with Major Aortopulmonary Collateral Arteries

Staged Treatment Using Right Ventricular Outflow Tract Stenting for Effective Augmentation of Native Pulmonary Arteries in a Case of Tetralogy of Fallot with Major Aortopulmonary Collateral Arteries

Inhaled Tranexamic Acid As a Novel Treatment for Pulmonary Hemorrhage in Critically Ill Pediatric Patients: An Observational Study.

Objectives:To describe the use of inhaled or endotracheally instilled tranexamic acid in critically ill pediatric patients for the treatment of pulmonary hemorrhage, which can be severe, life-threatening, and include potentially high-risk management procedures.Design:Retrospective observational study from 2011-2018 with patients followed until hospital discharge.Setting:Free-standing children’s hospital with an annual ICU volume of more than 3,500 yearly admissions.Patients:Pediatric patients, ages 0 to 18 years, admitted to an ICU and who received at least one dose of inhaled or endotracheally instilled tranexamic acid were included.Interventions:Inhaled or endotracheally instilled tranexamic acid.Measurements and Main Results:This study described the efficacy and adverse effects of patients who received inhaled or endotracheally instilled tranexamic acid. A total of 19 patients met inclusion criteria; median age was 72 months (11–187 mo), most patients were female (11, 58%), and almost half our patients (8, 42%) had congenital heart disease. Nine of 19 encounters (47%) had diffuse alveolar hemorrhage, four (21%) had pulmonary hemorrhage related to major aortopulmonary collateral arteries, two (11%) had mucosal airway bleeding, two (11%) were iatrogenic, one had a pulmonary embolism, and one patient did not have their etiology of pulmonary hemorrhage determined. Cessation of pulmonary hemorrhage was achieved in 18 of 19 patients (95%) with inhaled tranexamic acid with no major adverse events recorded.Conclusions and Relevance:We demonstrate that inhaled tranexamic acid may be safely used to treat pulmonary hemorrhage from varied etiologies in critically ill pediatric patients. Prospective studies are required in this vulnerable population to determine optimal dosing and delivery strategies, as well as to define any differential effect according to etiology.

Surgical Management of Fallot's Tetralogy With Pulmonary Atresia and Major Aortopulmonary Collateral Arteries: Multistage Versus One-Stage Repair.

A strict and rational approach to Fallot's tetralogy with pulmonary atresia and major aortopulmonary collateral arteries allows to achieve optimal results. Rehabilitative and unifocalization strategies do not constitute separate philosophies; instead the surgical strategy should be tailored to each individual patient. Based on our previous experience, the ability to achieve definitive intracardiac repair is the real determinant of both improved survival and adequate systolic right ventricular performance on mid-term follow-up.

Patient-Specific 3-Dimensional-Bioprinted Model for In Vitro Analysis and Treatment Planning of Pulmonary Artery Atresia in Tetralogy of Fallot and Major Aortopulmonary Collateral Arteries.

BackgroundTetralogy of Fallot with major aortopulmonary collateral arteries is a heterogeneous form of pulmonary artery (PA) stenosis that requires multiple forms of intervention. We present a patient‐specific in vitro platform capable of sustained flow that can be used to train proceduralists and surgical teams in current interventions, as well as in developing novel therapeutic approaches to treat various vascular anomalies. Our objective is to develop an in vitro model of PA stenosis based on patient data that can be used as an in vitro phantom to model cardiovascular disease and explore potential interventions.Methods and ResultsFrom patient‐specific scans obtained via computer tomography or 3‐dimensional (3D) rotational angiography, we generated digital 3D models of the arteries. Subsequently, in vitro models of tetralogy of Fallot with major aortopulmonary collateral arteries were first 3D printed using biocompatible resins and next bioprinted using gelatin methacrylate hydrogel to simulate neonatal vasculature or second‐order branches of an older patient with tetralogy of Fallot with major aortopulmonary collateral arteries. Printed models were used to study creation of extraluminal connection between an atretic PA and a major aortopulmonary collateral artery using a catheter‐based interventional method. Following the recanalization, engineered PA constructs were perfused and flow was visualized using contrast agents and x‐ray angiography. Further, computational fluid dynamics modeling was used to analyze flow in the recanalized model.ConclusionsNew 3D‐printed and computational fluid dynamics models for vascular atresia were successfully created. We demonstrated the unique capability of a printed model to develop a novel technique for establishing blood flow in atretic vessels using clinical imaging, together with 3D bioprinting–based tissue engineering techniques. Additive biomanufacturing technologies can enable fabrication of functional vascular phantoms to model PA stenosis conditions that can help develop novel clinical applications.

Systemic‐to‐pulmonary shunt vs right ventricle to pulmonary artery connection in the treatment of pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries

The systemic-to-pulmonary shunt (SPS) and right ventricle to pulmonary artery (RV-PA) connection were evaluated to pursue the goal of rehabilitating dysplastic native PAs via establishment of antegrade blood flow. However, the application of these two palliative operations was still confusing. We compared the two operations to determine their different effects on patients who have pulmonary atresia, ventricular septal defects, and major aortopulmonary collateral arteries (MAPCAs). From January 2011 to January 2016, 44 patients received the SPS procedure, and 54 patients received the RV-PA connection procedure; these procedures were compared based on perioperative data and follow-up data. There was no significant difference between the two groups for follow-up time (15.5 ± 11.8 vs 11.4 ± 10 months; P = .073). The SPS patients had a smaller preoperative pulmonary artery index (68.57 ± 38.25 vs 112.62 ± 61.63 mm2 /m2 ; P < .01), more MAPCAs (2.4 ± 1.1 vs 1.8 ± 1.5; P = .045) and had a shorter intubation time (26.73 ± 27.20 vs 40.88 ± 36.93 hours; P = .045), intensive care unit stay (3.6 ± 3.9 vs 5.7 ± 5.5 days; P = .033), and hospital stay (9.9 ± 3.9 vs 14.7 ± 11.9 days; P = .014) than the RV-PA connection patients. The cumulative complete repair rate and cumulative survival rate did not differ significantly between the two groups. Both the SPS and the RV-PA connection could rehabilitate the PA and produce complete repair, while the SPS could achieve better early postoperative outcomes and be suitable for patients with severe dysplastic PAs and large MAPCAs.

Does Repair of Tetralogy of Fallot Have Age Restrictions?

This publication presents case report of primary non-corrected adult congenital heart disease, tetralogy of Fallot, in forty-seven years old female patient. Clinical and anatomic issues were estimated within postoperative follow-up period and literature concerning surgical repair of tetralogy of Fallot in adult with congenital heart disease was reviewed.&#x0D; The aim. There was presentation the case report of adult patient with tetralogy of Fallot after surgical repair carried out at our Institution, as well as literature review concerning grown-up patients with tetralogy of Fallot in early and late postoperative period.&#x0D; Materials and methods. Female patient, forty-seven years old with grown-up congenital heart disease, tetralogy of Fallot with severe comorbidity.&#x0D; Results. Tetralogy of Fallot was radically repaired with high estimated operative risks. In early postoperative period there was increased exudation through both pleural drainages due to the function of major aortopulmonary collateral arteries. The decision was made to perform interventional closure of major aortopulmonary collateral arteries which enabled to discharge patient within 23 days in satisfactory condition.&#x0D; Conclusions. Presented case report and literature review show that the patient`s age is not a contraindication for repair of tetralogy of Fallot in adults with congenital heart disease. Patients with tetralogy of Fallot usually do not survive until adult age without surgical repair. Our presented case report and literature review show that surgery correction of tetralogy of Fallot in grown-up patients above 40 years of age should be performed in specialized centers experienced in pediatric cardiac surgery and in management of adult congenital heart disease regardless of patient age.

Perfusion Methods and Modifications to the Cardiopulmonary Bypass Circuit for Midline Unifocalization Procedures

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCAs) is a rare form of congenital heart disease. The midline unifocalization procedure has been developed for the treatment of PA/VSD/MAPCAs. These are complex and very lengthy procedures that require an entirely different method of perfusion. The purpose of this study was to review our perfusion modifications to support these unifocalization procedures. Sixty-four unifocalization procedures have been performed at our institution during the past 3 years. The median age was 4.1 months (range 1 month–3.5 years) and the median weight at surgery was 4.5 kg (range 3.5–19 kg). The median duration of cardiopulmonary bypass was 352 minutes (range 128–629 minutes), and the median duration of cross-clamp was 24 minutes (range 14–72 minutes). The conduct of surgery included cooling to a rectal perfusion temperature of 25° and a flow rate of 100 mL/kg/min. A pH-stat strategy and del Nido cardioplegia were used. Modifications to the cardiopulmonary bypass circuit include upsizing the oxygenator, reservoir, cannulae, vent catheter, and tubing. All circuits were modified to include the capability of performing an intraoperative flow study. This study is used to determine whether the VSD can be closed during surgery. A collateral flow study circuit is also set up for first-time operations to measure the residual collateral flow after all of the MAPCAs have been harvested. Patients who require midline unifocalization will invariably require very lengthy periods of support on cardiopulmonary bypass. We have adapted our perfusion circuitry to prepare for the demands on the bypass circuit to meet the requirements of this patient population. Our institution has developed a systematic approach for the conduct of perfusion to best serve our patients presenting with PA/VSD/MAPCAs.

Fetal pulmonary atresia with ventricular septal defect: Features, associations, and outcome in fetuses with different pulmonary circulation supply types.

To assess features and outcome in fetuses with pulmonary atresia with ventricular septal defect (PA-VSD). Fetuses with PA-VSD were prospectively enrolled and grouped on the basis of the pulmonary blood supply, including type A (only arterial duct [DA]), type B (both DA and major aortopulmonary collateral arteries [MAPCAs] present), and type C (MAPCAs only). The echocardiography features, associated chromosomal/genetic malformations, and postnatal outcome were compared among the three groups. Fifty-five fetuses with PA-VSD were enrolled. The presence of confluent PAs varied, with the highest displaying rate in type A and lowest rate in type C (100% vs 41.1%). The intrapericardial pulmonary arteries in all groups were hypoplastic but smaller in types B and C than in type A (P < .05). Deletion of 22q11.2 and right aortic arch were more frequently observed in types B and C than in type A. At the end of the study, overall survival rates in type C were lower than those in type A (22.1% vs 77.3%). There are great differences in the size of pulmonary arteries, associated genetic malformations, and perinatal outcomes among fetuses with PA-VSD. These results could be used for family counseling and surgical planning.

Late correction of tetralogy of Fallot in children.

To report our experience of late correction after infancy in patients with tetralogy of Fallot (ToF). Observational single-centre retrospective analysis of the surgical techniques and perioperative development of patients from developing countries undergoing total surgical correction of ToF after infancy, between 1 November 2011 and 30 November 2016. Variables are presented as numbers with percentages or as mean &plusmn; standard deviation. Due to the setting of the humanitarian programme, clinical and echocardiographic follow-up procedures could be conducted for only one month postoperatively. Twenty-five children (mean age: 70.8 &plusmn; 42 months, range 23-163; 44% female) underwent total surgical correction of ToF. Two patients (0.8%) initially received a Blalock-Taussig shunt and underwent subsequent correction 24 and 108 months later, respectively. Preoperative mean right ventricular/pulmonary artery (RV/PA) gradient was 84 &plusmn; 32 mm Hg, with a Nakata index of 164 &plusmn; 71 mm2/m2. Major aortopulmonary collateral arteries (MAPCAs) were observed in eight children (32%), six (26%) of whom underwent transcatheter closure before surgery. 24 children (96%) underwent a valve-sparing pulmonary valve repair and one patient received a transannular patch (TAP). There were no cases which saw major adverse cardiac and cerebrovascular events (MACCE). Mean duration of mechanical ventilation was 28 &plusmn; 19.6 hours (range 7-76). Pre-discharge echocardiography demonstrated a mean RV/PA gradient of 25 &plusmn; 5.7 mm Hg, with left ventricular ejection fraction &gt;60% in all cases. Overall length of hospital stay was 11.7 &plusmn; 4.5 days. There were no in-hospital mortality cases. Late surgical correction of ToF can be safely performed and produce highly satisfying early postoperative results comparable to those of classical &ldquo;timely&rdquo; correction. A valve-sparing technique can be applied in the majority of children.

Anesthetic Management for Caesarean Delivery in Patient With Uncorrected Pulmonary Atresia, Ventricular Septal Defect, and Major Aortopulmonary Collateral Arteries

(Int J Obstet Anesth. 2018;36:125–129) Pulmonary atresia with ventricular septal defect and major aortopulmonary arteries (PA/VSD/MAPCAs) is a rare cyanotic cardiac malformation that is associated with a high mortality rate. In this condition, there is no pulmonary valve, and the pulmonary vascular bed is supplied by aortopulmonary collateral arteries. The management of anesthesia for cesarean delivery in a woman with this uncorrected congenital heart defect is challenging. It is essential that a management plan is developed before the patient presenting in labor. This report detailed the anesthetic management of a 24-year-old primigravid woman with PA/VSD/MAPCAs.

Fatal thromboembolism of major aortopulmonary collateral arteries

Fatal thromboembolism of major aortopulmonary collateral arteries

Fetal pulmonary atresia with ventricular septal defect: echocardiographic findings, associated anomalies and chromosomal characteristics

Objective To analyze the echocardiographic findings, associated anomalies and chromosomal characteristics in fetuses with pulmonary atresia with ventricular septal defect (PA/VSD). Methods The echocardiographic data and follow-up materials were retrospectively reviewed in 30 256 fetuses from December 2012 to March 2018 in the consultation center of fetal heart disease in maternal-fetal medicine in Anzhen hospital. Of all the fetuses, 59 cases (0.19%) had PA/VSD. The echocardiographic findings, associated anomalies and chromosomal characteristics were retrospectively analyzed in all the 59 fetuses with PA/VSD. Based on whether the presence of the native pulmonary arteries and the major aortopulmonary collateral arteries (MAPCAs) or not, the PA-VSD was classified into type A, type B, and type C. Results A large ventricular defect was demonstrated in five-chamber view with 61.7% of the mean ratio of the aortic overriding. Other fetal echocardiographic features of all the 59 fetuses with PA/VSD included: the right aortic arch (n=19), reversal flow in the ductus arteriosus (n=40), MAPCAs (n=24). The classification of the PA/VSD included: type A (n=35), type B (n=5) and type C (n=19). Associated anomalies: persistent left superior vena cava (n=13), anomalous pulmonary vein connection (n=5), complete atrioventricular septal defect (n=5); single umbilical artery (n=3), right atrial isomerism (n=3). Of all the 30 cases performed chromosomal test, 3 cases had aneuploidy and 7 cases had microdeletion of chromosome. Conclusions The fetal echocardiographic findings of the PA/VSD are characteristic. For prenatal diagnosis of PA/VSD, the type of PA/VSD should be defined and chromosomal test should be performed, which can be helpful for prenatal consulting. Key words: Echocardiography; Heart septal defect, ventricular; Pulmonary atresia; Prenatal diagnosis; Chromosomal aberrations

Outcomes After Aortopulmonary Window for Hypoplastic Pulmonary Arteries and Dual-Supply Collaterals

Our institutional approach to tetralogy of Fallot with major aortopulmonary collateral arteries (MAPCAs) emphasizes early unifocalization and complete repair (CR). In the small subset of patients with dual-supply MAPCAs and confluent but hypoplastic central pulmonary arteries (PAs), our surgical approach is early creation of an aortopulmonary window (APW) to promote PA growth. Factors associated with successful progression to CR and mid-term outcomes have not been assessed. Clinical data were reviewed. PA diameters were measured offline from angiograms prior to APW and on follow-up catheterization >1 month after APW but prior to any additional surgical interventions. From November 2001 to March 2018, 352 patients with tetralogy of Fallot/MAPCAs underwent initial surgery at our center, 40 of whom had a simple APW with or without ligation of MAPCAs as the first procedure (median age, 1.4 months). All PA diameters increased significantly on follow-up angiography. Ultimately, 35 patients underwent CR after APW. Nine of these patients (26%) underwent intermediate palliative operation between 5 and 39 months (median, 8 months) after APW. There were no early deaths. The cumulative incidence of CR was 65% 1 year post-APW and 87% at 3 years. Repaired patients were followed for a median of 4.2 years after repair; the median PA:aortic pressure ratio was 0.39 (range, 0.22 to 0.74). Most patients with tetralogy of Fallot/MAPCAs and hypoplastic but normally arborizing PAs and dual-supply MAPCAs are able to undergo CR with low right ventricular pressure after APW early in life. Long-term outcomes were good, with acceptable PA pressures in most patients.

Measurement of Residual Collateral Flow in Pulmonary Atresia With Major Aortopulmonary Collaterals

Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (MAPCAs) is a rare form of congenital heart disease characterized by the entirety of pulmonary blood flow originating from systemic vessels. This study measured the residual collateral flow after harvesting of the MAPCAs for surgical repair. The study enrolled 32 patients with pulmonary atresia with ventricular septal defect and MAPCAs who were undergoing their first surgical procedure. The median age was 6.8 months, and median weight was 5.7 kg. The patients had a mean of 4.2 ± 0.7 MAPCAs. The cardiopulmonary bypass circuit was modified to contain a diversion loop in the left ventricular vent system to accurately measure residual collateral flow. During the period of aortic cross-clamp (for ventricular septal defect repair), the diversion loop was opened for 1-minute intervals, and the residual collateral flow collected. The systemic perfusion temperature was 25° and flow rate was 100 mL · kg-1 · min-1. The mean residual collateral flow was 5.5 mL · kg-1 · min-1 (range, 0.8 to 15.2 mL · kg-1 · min-1). The corresponding calculated pulmonary blood flow-to-systemic blood flow ratio values ranged from 1.01 to 1.36. There was a significant correlation between residual collateral flow and preoperative saturation (p < 0.05). The data demonstrate a wide range of residual collateral flow values after harvesting of the MAPCAs. The amount of residual collateral flow was correlated with preoperative saturation. These results suggest that some patients at the higher end of this spectrum may require adjustments in pump flow to assure adequate systemic perfusion.