Association of blood products administration during cardiopulmonary bypass and excessive post-operative bleeding in pediatric cardiac surgery

A case-control study of bleeding risk in children with 22q11.2 deletion syndrome undergoing cardiac surgery

Previous research suggests that individuals with 22q11.2 deletion syndrome (DS) have an increased risk of bleeding following cardiac surgery. However, current guidelines for management of patients with 22q11.2DS do not provide specific recommendations for perioperative management. This study sought to identify specific risk factors for bleeding in this patient population. Examine the factors determining bleeding and transfusion requirements in patients with 22q11.2DS undergoing cardiac surgery. This was a single center review of patients who underwent cardiac surgery at the Children's Hospital of Philadelphia from 2000 to 2016. Data was extracted from the medical record. Frequency of bleeding events, laboratory values, and transfusion requirements were compared. We included 226 patients with 22q11.2DS and 506 controls. Bleeding events were identified in 13 patients with 22q11.2DS (5.8%) and 27 controls (5.3%). Platelet counts were lower among patients with 22q11.2DS than in control patients, but not statistically different comparing bleeding to not bleeding. Patients with 22q11.2DS received more transfusions (regardless of bleeding status). However, multivariate analysis showed only procedure type was associated with increased risk of bleeding (p = .012). The overall risk of bleeding when undergoing cardiac surgery is not different in patients with 22q11.2DS compared to non-deleted patients. Though platelet counts were lower in patients with 22q11.2DS, only procedure type was significantly associated with an increased risk of bleeding.

Use of low titer O whole blood in infants and young children undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Low titer group O whole blood (LTOWB) is commonly used for severe bleeding in trauma patients. LTOWB may also benefit young children requiring cardiac surgery with cardiopulmonary bypass (CPB) at risk of severe bleeding.

STUDY DESIGN AND METHODS

In this retrospective study, children <2 years old who underwent cardiac surgery with CPB were included. Comparisons were performed between those receiving component therapy (CT) versus those receiving LTOWB plus CT (LTOWB+CT). Outcomes included drainage tube (DT) output and total transfusion volumes. Optimization-based weighting was used for adjusted analyses between groups.

RESULTS

There were 117 patients transfused with only CT and 127 patients transfused with LTOWB+CT. In the LTOWB+CT group, 66 were Group non-O and 61 were Group O. Total transfusion volumes given from the start of the operation until the first 24 h in the cardiac intensive care unit was a median (IQR) 41 (10, 93) mL/kg in the CT group and 48 (28, 77) mL/kg in the LTOWB+CT group, (p = .28). Median (IQR) DT output was 22 (15-32) in CT versus 22 (16-28) in LTOWB+CT groups, (p = .27). There were no differences in death, renal failure and a composite of death and renal failure between the two groups, but there were statistically fewer re-explorations for bleeding in the LTOWB+CT group (p < .001).

CONCLUSIONS

The use of LTOWB appears to be safe in <2 years old undergoing cardiac surgery and may reduce re-explorations for severe bleeding. Large trials are needed to determine the efficacy and safety of LTOWB in this population with severe bleeding.

Use of apixaban in children awaiting heart transplantation

BACKGROUND

The use of apixaban in the pediatric cardiac population is expanding. We describe our apixaban dosing and monitoring strategy in children and young adults awaiting heart transplantation, along with outcomes related to bleeding and thrombosis during wait-list and early post-transplant periods.

METHODS

This study is a retrospective, single-center analysis of all patients receiving apixaban while awaiting cardiac transplantation. Weight-based dosing was monitored with peak drug-specific anti-Xa chromogenic analysis. Significant post-operative bleeding defined by chest tube output or need for surgical intervention.

RESULTS

From September 2020 to December 2022, 19 patients, median age 13.5 years (6.1, 15.8 years), weighing 48.9 kg (15.4, 67.6) received apixaban while awaiting transplant. Indication for apixaban was prophylaxis (n = 18, 3 with ventricular assist devices) and treatment of thrombus (n = 1). There were no clinically relevant non-major or major bleeding, nor thrombotic events while awaiting transplant. The median time from last apixaban dose to arrival in the operating room was 23.2 h (15.6-33.8), with median random apixaban level of 37 ng/mL (28.3, 59), 6.3 h (4.8, 8.4) prior to arrival in the operating room. In this study, 32% of patients had significant post-operative bleeding based on chest tube output post-transplant or need for intervention. No patients meeting criteria for significant post-operative bleeding were thought to be attributable to apixaban.

CONCLUSIONS

Careful use of apixaban can be safe and effective while awaiting heart transplant. There was no appreciable increase in peri-operative bleeding. The use of apixaban is promising in providing safe, predictable and efficacious anticoagulation while avoiding additional patient stressors.

Predictors of Mediastinal Exploration While on Extracorporeal Membrane Oxygenation After Pediatric Cardiac Surgery

Cardiac surgical patients requiring extracorporeal membrane oxygenation (ECMO) are at increased risk for hemorrhage due to necessary anticoagulation, in-situ cannulas, and disturbed hemostasis. We performed a retrospective, cross-sectional study of patients 0-18 years old in our cardiac intensive care unit (CICU) cannulated to ECMO within 48 h of cardiopulmonary bypass. The 69 patients included in the study were divided into three analysis groups based on serial chest tube output per hour: no bleeding (NB) on admission to the CICU (21/69, 30%), bleeding stopped (BS) with medical management (26/69, 38%), bleeding requiring emergent mediastinal exploration (BME) (22/69, 32%). The NB group had a more favorable coagulation profile upon admission to the CICU (PTT 53 s NB, 105 s BS, 83 s BME p < 0.001, ACT 169 s NB, 225 s BS, 211 s BME, p =0.013). Only chest tube output during the first three postcannulation hours remained associated with the need for mediastinal exploration by multivariable analysis. An average chest-tube output of 11.6 mL/kg/h during the first three hours had the highest percentage of patients classified correctly (84%) for requiring mediastinal exploration during their ECMO run (sensitivity 91%, specificity 81%).

Intraoperative blood product transfusion in pediatric cardiac surgery patients: A retrospective review of adverse outcomes

BACKGROUND

Resuscitation with blood products is often required for pediatric cardiac surgery patients following cardiopulmonary bypass. However, data suggest that blood product transfusion is an independent predictor of adverse outcomes. Most studies have specifically found detrimental effects of overall transfusion of red blood cells in particular, but few have analyzed outcomes by the other specific blood product components.

AIMS

The objective of this study is to analyze adverse outcomes associated with intraoperative transfusion of specific blood product components.

METHODS

A retrospective review was performed on 643 pediatric patients who underwent cardiac surgery requiring cardiopulmonary bypass to evaluate the risk of selected adverse outcomes associated with intraoperative blood product transfusion. Adverse outcomes included thrombotic complications, stroke, acute kidney injury, prolonged mechanical ventilation, and death. Univariate logistic and linear regression analyses were performed to explore the association between various blood products and the occurrence of postoperative complications. Multiple logistic and linear regression analyses were performed adjusting for age, cyanotic status, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Score (STAT score), and cardiopulmonary bypass time.

RESULTS

Unadjusted analysis using univariate logistic and linear regressions showed statistically significant associations of almost all blood components (per 10 mL/kg dose increments) with multiple postoperative complications, including mortality, thrombotic complications, stroke, and days of mechanical ventilation. After adjusting for patient age, cyanotic status, STAT score, and cardiopulmonary bypass time, multivariable logistic and linear regression analyses revealed no association between transfusion of blood products with acute kidney injury and stroke. Administration of red blood cells was the only category significantly correlated with increased days of mechanical ventilation (0.5 days increase in mechanical ventilation per 10 mL/kg transfusion of red blood cells). The only blood product to show complete lack of a statistically significant association with any of the studied outcomes was cryoprecipitate.

CONCLUSIONS

Transfusion of blood products following cardiopulmonary bypass is associated with postoperative adverse outcomes. Future studies aimed at strategies to reduce intraoperative bleeding and decrease the amount of blood products administered are warranted.

Plasma and Platelet Transfusions Strategies in Neonates and Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass or Neonates and Children Supported by Extracorporeal Membrane Oxygenation: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present the recommendations and consensus statements with supporting literature for plasma and platelet transfusions in critically ill neonates and children undergoing cardiac surgery with cardiopulmonary bypass or supported by extracorporeal membrane oxygenation from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of nine experts developed evidence-based and, when evidence was insufficient, expert-based statements for plasma and platelet transfusions in critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation. These statements were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding experts. A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020. Consensus was obtained using the Research and Development/University of California, Los Angeles Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed one good practice statement, two recommendations, and three expert consensus statements.

CONCLUSIONS

Whereas viscoelastic testing and transfusion algorithms may be considered, in general, evidence informing indications for plasma and platelet transfusions in neonatal and pediatric patients undergoing cardiac surgery with cardiopulmonary bypass or those requiring extracorporeal membrane oxygenation support is lacking.

Bleeding in Critically Ill Children-Review of Literature, Knowledge Gaps, and Suggestions for Future Investigation

Clinically significant bleeding complicates up to 20% of admissions to the intensive care unit in adults and is associated with severe physiologic derangements, requirement for significant interventions and worse outcome. There is a paucity of published data on bleeding in critically ill children. In this manuscript, we will provide an overview of the epidemiology and characteristics of bleeding in critically ill children, address the association between bleeding and clinical outcomes, describe the current definitions of bleeding and their respective limitations, and finally provide an overview of current knowledge gaps and suggested areas for future research.

Use of Factor VIIa and Anti-inhibitor Coagulant Complex in Pediatric Cardiac Surgery Patients

OBJECTIVES

Postoperative bleeding is a common cause of morbidity and mortality in cardiac patients who undergo cardiopulmonary bypass (CPB). Pediatric patients are especially at risk for adverse effects of surgery and CPB on the coagulation system. This can result in bleeding, transfusions, and poor outcomes. Excessive bleeding unresponsive to blood products can warrant the off-label use of recombinant activated clotting factor VIIa (rFVIIa) and/or anti-inhibitor coagulant complex (FEIBA). Several studies have shown the utility in these agents off-label in patients who have undergone cardiac bypass surgery with acute bleeding episodes that are refractory to blood products. However, data regarding use of these agents in pediatrics are sparse. The purpose of this study is to report the use of rFVIIa and FEIBA in pediatric cardiac surgery patients in our institution.

METHODS

This was a retrospective chart review of pediatric cardiothoracic surgery patients who received rFVIIa or FEIBA at Children's Healthcare of Atlanta during the study period.

RESULTS

Thirty-three patients received rFVIIa and 9 patients received FEIBA either intraoperatively or postoperatively for bleeding related to the cardiac procedure. Approximately 13% of rFVIIa patients and 55% of FEIBA patients required repeat doses. There were decreases for all blood products administered after rFVIIa and FEIBA were given. However, the doses used did not correlate with either positive or negative outcomes. Seventeen percent (n = 7) of rFVIIa patients experienced a thrombus and 22% (n = 2) of FEIBA patients experienced a thrombus.

CONCLUSIONS

Both rFVIIa and FEIBA reduced blood product usage in pediatric patients following cardiac procedures.

Heparin-protamine balance after neonatal cardiopulmonary bypass surgery

Essentials Heparin-protamine balance (HPB) modulates bleeding after neonatal cardiopulmonary bypass (CPB). HPB was examined in 44 neonates undergoing CPB. Post-operative bleeding occurred in 36% and heparin rebound in 73%. Thrombin-initiated fibrin clot kinetic assay and partial thromboplastin time best assessed HPB.

SUMMARY

Background Neonates undergoing cardiopulmonary bypass (CPB) are at risk of excessive bleeding. Blood is anticoagulated with heparin during CPB. Heparin activity is reversed with protamine at the end of CPB. Paradoxically, protamine also inhibits blood coagulation when it is dosed in excess of heparin. Objectives To evaluate heparin-protamine balance in neonates undergoing CPB by using research and clinical assays, and to determine its association with postoperative bleeding. Patients/Methods Neonates undergoing CPB in the first 30 days of life were studied. Blood samples were obtained during and after surgery. Heparin-protamine balance was assessed with calibrated automated thrombography, thrombin-initiated fibrin clot kinetic assay (TFCK), activated partial thromboplastin time (APTT), anti-FXa activity, and thromboelastometry. Excessive postoperative bleeding was determined by measurement of chest tube output or the development of cardiac tamponade. Results and Conclusions Of 44 neonates enrolled, 16 (36%) had excessive postoperative bleeding. The TFCK value was increased. By heparin in neonatal blood samples, but was only minimally altered by excess protamine. Therefore, it reliably measured heparin in samples containing a wide range of heparin and protamine concentrations. The APTT most closely correlated with TFCK results, whereas anti-FXa and thromboelastometry assays were less correlative. The TFCK and APTT assay also consistently detected postoperative heparin rebound, providing an important continued role for these long-established coagulation tests in the management of postoperative bleeding in neonates requiring cardiac surgical repair. None of the coagulation tests predicted the neonates who experienced postoperative bleeding, reflecting the multifactorial causes of bleeding in this population.

Recommendations on RBC Transfusion in Infants and Children With Acquired and Congenital Heart Disease From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting literature for RBC transfusions in critically ill children with acquired and congenital heart disease developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of 38 international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

Experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations and research priorities for RBC transfusions in critically ill children. The cardiac disease subgroup included three experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA appropriateness method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Twenty-one recommendations were developed and reached agreement. For children with myocardial dysfunction and/or pulmonary hypertension, there is no evidence that transfusion greater than hemoglobin of 10 g/dL is beneficial. For children with uncorrected heart disease, we recommended maintaining hemoglobin greater than 7-9.0 g/dL depending upon their cardiopulmonary reserve. For stable children undergoing biventricular repairs, we recommend not transfusing if the hemoglobin is greater than 7.0 g/dL. For infants undergoing staged palliative procedures with stable hemodynamics, we recommend avoiding transfusions solely based upon hemoglobin, if hemoglobin is greater than 9.0 g/dL. We recommend intraoperative and postoperative blood conservation measures. There are insufficient data supporting shorter storage duration RBCs. The risks and benefits of RBC transfusions in children with cardiac disease requires further study.

CONCLUSIONS

We present RBC transfusion management recommendations for the critically ill child with cardiac disease. Clinical recommendations emphasize relevant hemoglobin thresholds, and research recommendations emphasize need for further understanding of physiologic and hemoglobin thresholds and alternatives to RBC transfusion in subpopulations lacking pediatric literature.

Recommendations on RBC Transfusions in Critically Ill Children With Acute Respiratory Failure From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting literature for RBC transfusions in critically ill children with bleeding developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

The panel of 38 experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations as well as research priorities for RBC transfusions in critically ill children. The respiratory subgroup included six experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Transfusion and Anemia Expertise Initiative experts developed seven recommendations focused on children with acute respiratory failure. All recommendations reached agreement (> 80%). Transfusion of RBCs in children with respiratory failure with an hemoglobin level less than 5 g/dL was strongly recommended. It was strongly recommended that RBCs not be systematically administered to children with respiratory failure who are hemodynamically stable and who have a hemoglobin level greater than or equal to 7 g/dL. Experts could not make a recommendation for children with hemodynamic instability, with severe hypoxemia and/or with an hemoglobin level between 5 and 7 g/dL. Specific RBC transfusion strategies using physiologic-based metrics and biomarkers could not be elaborated.

CONCLUSIONS

The Transfusion and Anemia Expertise Initiative Consensus Conference developed specific recommendations regarding RBC transfusion management in critically ill children with respiratory failure, as well as recommendations to guide future research. Clinical recommendations emphasize relevant hemoglobin thresholds. Research recommendations emphasize the need to identify appropriate physiologic thresholds, suggest a better understanding of alternatives to RBC transfusion, and identify the need for better evidence on hemoglobin thresholds that might be used in specific subpopulations of critically ill children.

The use of acute normovolemic hemodilution in paediatric cardiac surgery

BACKGROUND

Acute normovolemic hemodilution (ANH) is considered safe and effective in decreasing perioperative transfusion in paediatric populations undergoing high blood-loss surgeries. We determined the association between ANH and the intraoperative use of allogeneic blood products in paediatric cardiac surgery patients.

METHODS

This is a single-centre retrospective cohort study including paediatric patients between 0 and 36 months of age undergoing surgical repair or palliation of their cardiac defect with the use of cardiopulmonary bypass between November 2013 and November 2014. Our primary endpoint was the volume per kilogram of body weight of any blood product administered. Secondary endpoints were postoperative bleeding, coagulation profile, creatinine, vasoactive support, duration of mechanical ventilation, and hospital stay.

RESULTS

In all, 50 patients met eligibility criteria and were included. Of those, seven were exposed to ANH and while 43 patients were treated according to usual care. Baseline characteristics were similar in both groups. After adjustment for baseline characteristics including age, American Society of Anaesthesiologists (ASA) classification, and Risk Adjusted Congenital Heart Surgery score, ANH was associated with reduced administration of allogenic blood products, with the mean difference between groups of 57.5 ml/kg (95% CI: 34.8, 80.2). The ANH group had lower blood losses at 6 and 24 h postoperatively. There were no differences in the duration of ICU or hospital stay.

CONCLUSION

We found a reduction in the administration of blood products and lower postoperative blood losses associated with the use of ANH in paediatric cardiac surgery patients. The data suggest that ANH might be beneficial in reducing perioperative morbidity in this patient population.

Strategies for Prevention and Management of Bleeding Following Pediatric Cardiac Surgery on Cardiopulmonary Bypass: A Scoping Review

OBJECTIVE

We aimed to systematically describe, via a scoping review, the literature reporting strategies for prevention and management of mediastinal bleeding post pediatric cardiopulmonary bypass surgery.

DATA SOURCES

MEDLINE, EMBASE, PubMed, and Cochrane CENTRAL Register.

STUDY SELECTION

Two authors independently screened publications from 1980 to 2016 reporting the effect of therapeutic interventions on bleeding-related postoperative outcomes, including mediastinal drain loss, transfusion, chest re-exploration rate, and coagulation variables. Inclusions: less than 18 years, cardiac surgery on cardiopulmonary bypass.

DATA EXTRACTION

Data from eligible studies were extracted using a standard data collection sheet.

DATA SYNTHESIS

Overall, 299 of 7,434 screened articles were included, with observational studies being almost twice as common (n = 187, 63%) than controlled trials (n = 112, 38%). The most frequently evaluated interventions were antifibrinolytic drugs (75 studies, 25%), blood products (59 studies, 20%), point-of-care testing (47 studies, 16%), and cardiopulmonary bypass circuit modifications (46 studies, 15%). The publication rate for controlled trials remained constant over time (4-6/yr); however, trials were small (median participants, 51; interquartile range, 57) and overwhelmingly single center (98%). Controlled trials originated from 22 countries, with the United States, India, and Germany accounting for 50%. The commonest outcomes were mediastinal blood loss and transfusion requirements; however, these were defined inconsistently (blood loss being reported over nine different time periods). The majority of trials were aimed at bleeding prevention (98%) rather than treatment (10%), nine studies assessed both.

CONCLUSIONS

Overall, this review demonstrates small trial sizes, low level of evidence, and marked heterogeneity of reported endpoints in the included studies. The need for more, higher quality studies reporting clinically relevant, comparable outcomes is highlighted. Emerging fields such as the use of coagulation factor concentrates, goal-directed guidelines, and anti-inflammatory therapies appear to be of particular interest. This scoping review can potentially guide future trial design and form the basis for therapy-specific systematic reviews.

Validation of a definition of excessive postoperative bleeding in infants undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVE

To derive and validate an objective definition of postoperative bleeding in neonates and infants undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

Using a retrospective cohort of 124 infants and neonates, we included published bleeding definitions and cumulative chest tube output over different postoperative periods (eg, 2, 12, or 24 hours after intensive care unit admission) in a classification and regression tree model to determine chest tube output volumes that were associated with red blood cell transfusions and surgical re-exploration for bleeding in the first 24 hours after intensive care unit admission. After the definition of excessive bleeding was determined, it was validated via a prospective cohort of 77 infants and neonates.

RESULTS

Excessive bleeding was defined as ≥7 mL/kg/h for ≥2 consecutive hours in the first 12 postoperative hours and/or ≥84 mL/kg total for the first 24 postoperative hours and/or surgical re-exploration for bleeding or cardiac tamponade physiology in the first 24 postoperative hours. Excessive bleeding was associated with longer length of hospital stay, increased 30-day readmission rate, and increased transfusions in the postoperative period.

CONCLUSIONS

The proposed standard definition of excessive bleeding is based on readily obtained objective data and relates to important early clinical outcomes. Application and validation by other institutions will help determine the extent to which our specialty should consider this definition for both clinical investigation and quality improvement initiatives.

Strategies for blood conservation in pediatric cardiac surgery

Cardiac surgery accounts for the majority of blood transfusions in a hospital. Blood transfusion has been associated with complications and major adverse events after cardiac surgery. Compared to adults it is more difficult to avoid blood transfusion in children after cardiac surgery. This article takes into account the challenges and emphasizes on the various strategies that could be implemented, to conserve blood during pediatric cardiac surgery.

Bleeding and Thrombosis in Pediatric Cardiac Intensive Care

OBJECTIVES

The objective of this article is to review the particular tendencies as well as specific concerns of bleeding and clotting in children with critical cardiac disease.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSION

Children with critical heart disease are at particular risk for bleeding and clotting secondary to intrinsic as well as extrinsic factors. We hope that this review will aid the clinician in managing the unique challenges of bleeding and clotting in this patient population, and serve as a springboard for much needed research in this area.

Mechanical blood trauma in assisted circulation: sublethal RBC damage preceding hemolysis

After many decades of improvements in mechanical circulatory assist devices (CADs), blood damage remains a serious problem during support contributing to variety of adverse events, and consequently affecting patient survival and quality of life. The mechanisms of cumulative cell damage in continuous-flow blood pumps are still not fully understood despite numerous in vitro, in vivo, and in silico studies of blood trauma. Previous investigations have almost exclusively focused on lethal blood damage, namely hemolysis, which is typically negligible during normal operation of current generation CADs. The measurement of plasma free hemoglobin (plfHb) concentration to characterize hemolysis is straightforward, however sublethal trauma is more difficult to detect and quantify since no simple direct test exists. Similarly, while multiple studies have focused on thrombosis within blood pumps and accessories, sublethal blood trauma and its sequelae have yet to be adequately documented or characterized. This review summarizes the current understanding of sublethal trauma to red blood cells (RBCs) produced by exposure of blood to flow parameters and conditions similar to those within CADs. It also suggests potential strategies to reduce and/or prevent RBC sublethal damage in a clinically-relevant context, and encourages new research into this relatively uncharted territory.

Effect of 22q11.2 deletion on bleeding and transfusion utilization in children with congenital heart disease undergoing cardiac surgery

BACKGROUND

Postsurgical bleeding causes significant morbidity and mortality in children undergoing surgery for congenital heart defects (CHD). 22q11.2 deletion syndrome (DS) is the second most common genetic risk factor for CHD. The deleted segment of chromosome 22q11.2 encompasses the gene encoding glycoprotein (GP) Ibβ, which is required for expression of the GPIb-V-IX complex on the platelet surface, where it functions as the receptor for von Willebrand factor (VWF). Binding of GPIb-V-IX to VWF is important for platelets to initiate hemostasis. It is not known whether hemizygosity for the gene encoding GPIbβ increases the risk for bleeding following cardiac surgery for patients with 22q11.2 DS.

METHODS

We performed a case-control study of 91 pediatric patients who underwent cardiac surgery with cardiopulmonary bypass from 2004 to 2012 at Children's Hospital of Wisconsin.

RESULTS

Patients with 22q11.2 DS had larger platelets and lower platelet counts, bled more excessively, and received more transfusion support with packed red blood cells in the early postoperative period relative to control patients.

CONCLUSION

Presurgical genetic testing for 22q11.2 DS may help to identify a subset of pediatric cardiac surgery patients who are at increased risk for excessive bleeding and who may require more transfusion support in the postoperative period.