Long-term implantable ventricular assist device support in children

BACKGROUND

In pediatrics, implantable continuous-flow ventricular assist devices (IC-VAD) are often used as a "temporary" support, bridging children to cardiac transplantation during the same hospital admission.

METHODS

We conducted a retrospective review of our consecutive patients undergoing IC-VAD support at a tertiary pediatric heart center between 2008 and 2022.

RESULTS

We identified 100 IC-VAD implant encounters: HeartWare HVAD (67; 67%), HeartMate II (17; 17%), and HeartMate 3 (16; 16%). The median (range) age, weight, and body surface area at implantation were 14.1 (3.0-56.5) years, 54.8 (13.3-140) kg, and 1.6 (0.6-2.6) m2, respectively. Cardiomyopathy (58; 58%) was the most common etiology, followed by congenital heart disease (37; 37%, including 13 single ventricle). At 6 months of IC-VAD support, 94 (94%) encounters achieved positive outcomes: ongoing support (59; 59%), transplant (33; 33%), and cardiac recovery (2; 2%). Eighty-two encounters (82%) resulted in home discharge with ongoing VAD support, including 38 (46%, out of 82) requiring readmission and 7 (9%, out of 82) resulting in death. There was a clinically significant decrease in morbidity rates before versus after home discharge: bleeding (1.55 vs 0.06), infection (0.84 vs 0.37), and stroke (0.84 vs 0.15 event per patient-year). Overall, 86 encounters (86%) reached positive end points at the latest follow-up (64 transplant, 15 ongoing support, and 7 recovery). Infection (29%; 4 of 14) was the most common cause of negative outcomes, followed by cerebrovascular accident (21%; 3), and unresolved frailty (21%; 3). The estimated overall survival at 1, 2, and 5 years was 90%, 86%, and 77%, respectively.

CONCLUSIONS

This study suggests the feasibility of outpatient management of pediatric IC-VAD support. The ability to offer true long-term support maximizes the potential of IC-VAD support, not limited to a temporary bridging tool for heart transplantation.

The History of Extracorporeal Membrane Oxygenation and the Development of Extracorporeal Membrane Oxygenation Anticoagulation

Extracorporeal membrane oxygenation (ECMO) was first started for humans in early 1970s by Robert Bartlett. Since its inception, there have been numerous challenges with extracorporeal circulation, such as coagulation and platelet activation, followed by consumption of coagulation factors and platelets, and biocompatibility of tubing, pump, and oxygenator. Unfractionated heparin (heparin hereafter) has historically been the defacto anticoagulant until recently. Also, coagulation monitoring was mainly based on bedside activated clotting time and activated partial thromboplastin time. In the past 50 years, the technology of ECMO has advanced tremendously, and thus, the survival rate has improved significantly. The indication for ECMO has also expanded. Among these are clinical conditions such as postcardiopulmonary bypass, sepsis, ECMO cardiopulmonary resuscitation, and even severe coronavirus disease 2019 (COVID-19). Not surprisingly, the number of ECMO cases has increased according to the Extracorporeal Life Support Organization Registry and prolonged ECMO support has become more prevalent. It is not uncommon for patients with COVID-19 to be on ECMO support for more than 1 year until recovery or lung transplant. With that being said, complications of bleeding, thrombosis, clot formation in the circuit, and intravascular hemolysis still remain and continue to be major challenges. Here, several clinical ECMO experts, including the "Father of ECMO"-Dr. Robert Bartlett, describe the history and advances of ECMO.

Retrospective Comparison of Recombinant Activated Factor VII Versus 4-Factor Prothrombin Complex Concentrate in Cardiac Surgical Patients

OBJECTIVES

To compare the incidences of postoperative thrombotic complications, transfusion of blood products, and chest tube output in congenital cardiac surgical patients who received either recombinant activated factor VII (rFVIIa) or 4-factor prothrombin complex concentrate (4F-PCC).

DESIGN

We performed a retrospective study.

SETTING

Patients who underwent surgery at a tertiary academic hospital.

PARTICIPANTS

Pediatric patients who underwent cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were obtained from the Society of Thoracic Surgeons and the Pediatric Cardiac Critical Care Consortium databases, as well as from manual chart review. Adjusted p values were obtained from multivariate regression using age (days), surgeon (number), cardiopulmonary bypass time (minutes), and need for deep hypothermic circulatory arrest (yes/no). A total of 55 patients were included in the 4F-PCC group, and 89 in the rFVIIa group. The median dose of rFVIIa was 77 mcg/kg (46-88), and the median dose of 4F-PCC was 31 IU/kg (24-43). The incidences of thrombotic complications were 8% in the 4F-PCC group and 30% in the rFVIIa group (adjusted p = 0.023). No difference was reported between the groups regarding chest tube output on days 1 and 2 or transfusion of blood products. Using a sensitivity analysis with propensity matching, the incidence of thrombosis was 10% in the 4F-PCC group (n = 38), and 31% in the rFVIIa group (n = 39) (p = 0.036). No difference was reported in terms of bleeding or transfusion.

CONCLUSIONS

This retrospective study suggested that the administration of rFVIIa was associated with a higher risk of thrombotic complications when compared to 4F-PCC, without benefits in terms of bleeding and transfusions.

[Case of Hematemesis Cardiopulmonary Arrest after Chemotherapy for Advanced Gastric Cancer]

The case is of a 66-year-old woman who visited a general practitioner with a chief complaint of cough. She was referred to the Internal Medicine Department of our hospital because an abnormal shadow was found in her chest X-ray examination. A CT scan suspected her to have a metastatic lung tumor, and gastric cancer was diagnosed on primary site search. The patient was started on G-SOX therapy. After 2 courses, she experienced massive hematemesis and was referred to the hospital. A CT scan revealed arterial bleeding into the stomach. She went into cardiac arrest shortly afterward, and cardiopulmonary resuscitation was started. Hemostasis was obtained by interventional radiology(IVR). Upper gastrointestinal endoscopy performed after hemostasis showed the tumor to be necrotic and shrunk. Bleeding from advanced gastric cancer is common; however, bleeding due to the effects of chemotherapy have been reported. We report a case of massive bleeding and cardiopulmonary arrest during chemotherapy.

D-Dimer Elevation at Time of Admission is Associated with Need for Ventilator Support among Pediatric Patients with COVID-19 Infection

BACKGROUND

This study aims to determine if coagulation abnormalities at presentation are associated with clinical severity of pediatric COVID-19 infection.

METHODS

We retrospectively reviewed admission coagulation studies (D-dimer, prothrombin time (PT), partial thromboplastin time with hepzyme, fibrinogen, and platelet count) with disease severity defined by need for ICU admission, ventilator support, and length of stay (LOS).

RESULTS

There were 110 pediatric patients (0.5 months to 18 years) who had coagulation studies collected within 24 hours of admission. Patients who required ICU admission and ventilation support had significantly higher D-dimer and PT values at presentation compared to patients who required neither. In addition, D-dimer showed moderate correlation with LOS.

CONCLUSIONS

Elevated D-dimer correlated significantly with severity of disease and LOS, while prolonged PT only correlated with disease severity. Our data suggest that D-dimer at presentation may predict a pediatric patient's need for ICU care or ventilator support.

Is it time to switch to bivalirudin for ECMO anticoagulation?

For decades, unfractionated heparin (hereafter, heparin) has been the primary anticoagulant used for extracorporeal membrane oxygenation (ECMO) support. More recently, however, bivalirudin, a direct thrombin inhibitor, has emerged as an alternative. This systematic review based on PRISMA guidelines, aims to summarize 16 comparative studies and 8 meta-analysis and review articles published from January, 2011 till May, 2023 which directly compares ECMO courses using heparin versus bivalirudin as the anticoagulant. While this comparison is complicated by the lack of a standardized definition of major bleeding or thrombosis, our overall findings suggest there is no statistical difference between heparin and bivalirudin in incidence of bleeding and thrombosis. That said, some studies found a statistical significance favoring bivalirudin in reducing major bleeding, thrombosis, and the need for transfusions. We also offer essential guidance for appropriately selecting an anticoagulant and monitoring its effect in ECMO settings.

Corrigendum to 'The Hemophilia Joint Health Score version 2.1 Validation in Adult Patients Study: A multicenter international study' [Research and Practice in Thrombosis and Haemostasis, 6/2, (2022) e12690]

[This corrects the article DOI: 10.1002/rth2.12690.].

Factor V Leiden-independent activated protein C resistance: Communication from the plasma coagulation inhibitors subcommittee of the International Society on Thrombosis and Haemostasis Scientific and Standardisation Committee

Activated protein C resistance (APC-R) due to the single-nucleotide polymorphism factor V Leiden (FVL) is the most common cause of hereditary thrombophilia. It is found predominantly in Caucasians and is uncommon or absent in other populations. Although FVL is responsible for >90% of cases of hereditary APC-R, a number of other F5 variants that also confer various degrees of APC-R and thrombotic risk have been described. Acquired APC-R due to increased levels of coagulation factors, reduced levels of inhibitors, or the presence of autoantibodies occurs in a variety of conditions and is an independent risk factor for thrombosis. It is common for thrombophilia screening protocols to restrict assessment for APC-R to demonstrating the presence or absence of FVL. The aim of this Scientific and Standardisation Committee communication is to detail the causes of FVL-independent APC-R to widen the diagnostic net, particularly in situations in which in vitro APC-R is encountered in the absence of FVL. Predilution clotting assays are not FVL specific and are used to detect clinically significant F5 variants conferring APC-R, whereas different forms of acquired APC-R are preferentially detected using the classical activated partial thromboplastin time-based APC-R assay without predilution and/or endogenous thrombin potential APC-R assays. Resource-specific recommendations are given to guide the detection of FVL-independent APC-R.

Blood transfusion is associated with increased mortality for neonates with congenital diaphragmatic hernia on extracorporeal membrane oxygenation support

BACKGROUND AND OBJECTIVES

Blood transfusion is frequently needed to maintain adequate haemostasis and improve oxygenation for patients treated with extracorporeal membrane oxygenation (ECMO). It is more so for neonates with immature coagulation systems who require surgical intervention such as congenital diaphragmatic hernia (CDH) repair. There is growing evidence suggesting an association between blood transfusions and increased mortality. The aim of this study is to evaluate the association of blood transfusions during the peri-operative period of CDH repair, among other clinical parameters, with mortality in neonates undergoing on-ECMO CDH repair.

MATERIALS AND METHODS

We performed a single centre retrospective chart review of all neonates with CDH undergoing on-ECMO surgical repair from January 2010 to December 2020. Logistic regression was used to investigate associations with survival status.

RESULTS

Sixty-two patients met the inclusion criteria. Platelet transfusions (odds ratio [OR] 1.42, 95% confidence interval [CI]: 1.06-1.90) in the post-operative period and ECMO duration (OR 1.17, 95% CI: 1.05-1.30) were associated with increased mortality. Major bleeding complications had the strongest association with mortality (OR 10.98, 95% CI: 3.27-36.91). Gestational age, birth weight, Apgar scores, sex, blood type, right versus left CDH, venovenous versus venoarterial ECMO and duration of ECMO before CDH repair and circuit change after adjusting for ECMO duration were not significantly associated with survival.

CONCLUSION

Platelet transfusion in the post-operative period and major bleeding are associated with increased mortality in CDH neonates with surgical repair. The data suggest a need to develop robust plans for monitoring and preventing coagulation aberrancies during neonatal ECMO support.

Diagnosis and management of severe congenital protein C deficiency (SCPCD): Communication from the SSC of the ISTH

Severe congenital protein C deficiency (SCPCD) is rare and there is currently substantial variation in the management of this condition. A joint project by three Scientific and Standardization Committees of the ISTH: Plasma Coagulation Inhibitors, Pediatric/Neonatal Thrombosis and Hemostasis, and Women's Health Issues in Thrombosis and Hemostasis, was developed to review the current evidence and help guide on diagnosis and management of SCPCD. We provide a summary of the clinical presentations, differential diagnoses, appropriate investigations to confirm the diagnosis, approaches for management of the acute situation, and options for long-term management including subsequent pregnancies. We finally provide a set of recommendations to help in this regard.

Consensus Statement: Hemostasis Trial Outcomes in Cardiac Surgery and Mechanical Support

BACKGROUND

Research evaluating hemostatic agents for the treatment of clinically significant bleeding has been hampered by inconsistency and lack of standardized primary clinical trial outcomes. Clinical trials of hemostatic agents in both cardiac surgery and mechanical circulatory support, such as extracorporeal membrane oxygenation and ventricular assist devices, are examples of studies that lack implementation of universally accepted outcomes.

METHODS

A subgroup of experts convened by the National Heart, Lung, and Blood Institute and the US Department of Defense developed consensus recommendations for primary outcomes in cardiac surgery and mechanical circulatory support.

RESULTS

For cardiac surgery the primary efficacy endpoint of total allogeneic blood products (units vs mL/kg for pediatric patients) administered intraoperatively and postoperatively through day 5 or hospital discharge is recommended. For mechanical circulatory support outside the perioperative period the recommended primary outcome for extracorporeal membrane oxygenation is a 5-point ordinal score of thrombosis and bleeding severity adapted from the Common Terminology Criteria for Adverse Events version 5.0. The recommended primary endpoint for ventricular assist device is freedom from disabling stroke (Common Terminology Criteria for Adverse Events AE ≥ grade 3) through day 180.

CONCLUSIONS

The proposed composite risk scores could impact the design of upcoming clinical trials and enable comparability of future investigations. Harmonizing and disseminating global consensus definitions and management guidelines can also reduce patient heterogeneity that would confound standardized primary outcomes in future research.

Convalescent plasma in hospitalized pediatric and obstetric coronavirus disease 2019 (COVID-19) patients

BACKGROUND

Published data on coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) use in children and obstetric patients are limited. We describe a single-center experience of hospitalized patients who received CCP for acute COVID-19.

METHODS

A retrospective review of children 0-18-years-old and pregnant patients hospitalized with laboratory-confirmed acute COVID-19 who received CCP from March 1, 2020 to March 1, 2021 was performed. Clinical and laboratory data were collected to assess the safety of CCP administration. Antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were measured in the CCP products and in patients before transfusion and at various time points post-transfusion. Correlation between the administered SARS-CoV-2 administered versus the SARS-CoV-2 anti-spike immunoglobulin response in patient serum was assessed.

RESULTS

Twenty-two children and ten obstetric patients were eligible. Twelve pediatric and eight obstetric patients had moderate disease and ten pediatric and two obstetric patients had severe disease. Five pediatric patients died. Eighteen of 37 (48.6%) CCP titers that were measured met US Food and Drug Administration (FDA) criteria for high immunoglobulin G (IgG) antibody titer. There were no complications with transfusion. High-titer CCP showed a positive correlation with rise in patient total immunoglobulin levels only in obstetric patients but not in pediatric patients. Among pediatric patients, the median serum antibody level increased over time after transfusion.

CONCLUSIONS

Coronavirus 2019 convalescent plasma was administered safely to our patients. Our study suggested that CCP did not interfere with endogenous antibody production. The antibody titer of CCP correlated with post-transfusion response only in obstetric patients. Randomized trials in pediatric and obstetric patients are needed to further understand how to dose CCP and evaluate efficacy.

548. Convalescent Plasma in Hospitalized Pediatric and Obstetric patients with COVID-19

Background

Published data on COVID-19 convalescent plasma (CCP) use in children and obstetric patients is limited. We describe a single-center experience of hospitalized patients who received CCP for acute COVID-19.

Methods

We performed a retrospective review of children 0-18-years-old and pregnant patients hospitalized with laboratory-confirmed acute COVID-19 who received CCP from March 1st, 2020 to March 1st, 2021. Clinical and laboratory data were collected to assess the safety of CCP administration. Antibodies to SARS-CoV-2 were measured before and at various timepoints post CCP transfusion. Correlation between SARS-CoV-2 immunoglobulin administered versus the SARS-CoV-2 anti-Spike immunoglobulin response in patient serum was assessed.

Results

Twenty-two children and 10 obstetric patients were eligible. 12 pediatric and 8 obstetric patients had moderate disease and 10 pediatric and 2 obstetric patients had severe disease. 5 pediatric patients died. 18/37 (48.6%) CCP units that were measured met FDA criteria for a high IgG titer. There were no complications with transfusion based on CDC, NHSN Biovigilance Component: Hemovigilance Module Surveillance Protocol. Two pediatric patients had fevers a few hours after CCP with low suspicion for a transfusion reaction. Median SARS-CoV-2 anti-spike antibody levels of pediatric patients post-transfusion for 0-7 days was 80.6AU/mL (range: 2-1070), 8-21 days was 180AU/mL (range: 12-661) and >21 days was 210AU/mL (range: 4.1-1220). For obstetric patients, post-transfusion antibody levels were only obtained 0-7 days post-transfusion with median 45AU/mL (range: 9.5-100). High-titer CCP showed a positive correlation with rise in patient immunoglobulin levels only in the obstetric patients but not in pediatric patients.

Conclusion

CCP was administered safely to our moderately to severely ill pediatric and obstetric patients. Among pediatric patients, the median serum antibody level increased over time after transfusion and suggested that CCP did not interfere with the endogenous antibody production. Antibody dose of high-titer CCP correlated with post-transfusion response in only obstetric patients. Randomized trials in pediatric and obstetric patients are needed to further understand how to dose CCP and evaluate efficacy.

Disclosures

Jun Teruya, MD, PhD, Apelo Consulting Pvt. Ltd (Consultant)Hemosonics (Other Financial or Material Support, Honorarium) Flor M. Munoz, MD, Biocryst (Scientific Research Study Investigator)Gilead (Scientific Research Study Investigator)Meissa (Other Financial or Material Support, DSMB)Moderna (Scientific Research Study Investigator, Other Financial or Material Support, DSMB)Pfizer (Scientific Research Study Investigator, Other Financial or Material Support, DSMB)Virometix (Other Financial or Material Support, DSMB)

Trimester-specific thromboelastic values and coagulation activation markers in pregnancy compared across trimesters and compared to the nonpregnant state

INTRODUCTION

Rotational thromboelastometry (ROTEM) rapidly identifies deficits underlying coagulopathy during massive hemorrhage. Prompt coagulopathy correction is balanced with the risk of blood product overutilization, making the ability to quickly target therapy highly desirable. However, data about ROTEM reference ranges in pregnancy are limited. We hypothesized that ROTEM parameters change across trimesters of pregnancy and differ from the nonpregnant state. Also, we sought to identify which hemostatic test best predicts coagulation activation during pregnancy.

METHODS

A prospective cohort study in healthy pregnant patients in the first (n = 34), second (n = 34), and third trimesters (n = 41) against healthy, nonpregnant controls (n = 33) was performed. Citrated blood was collected, and ROTEM, complete blood count, and plasma-based assays of coagulation were performed. Mean ± SD or median [IQR] were compared across trimesters and between each trimester against the nonpregnant state. ROTEM parameters vs. plasma-based assays were also compared.

RESULTS

Maximum clot firmness and A10 in FIBTEM correlated strongly with fibrinogen level. INTEM and EXTEM values demonstrated only weak to modest correlation with corresponding tests using plasma assays. Thrombin antithrombin complex (TAT) increased from the first trimester onward, whereas other coagulation activation markers did not show difference compared with control group.

CONCLUSION

Rotational thromboelastometry parameters differ variably across trimesters of pregnancy and compared with the nonpregnant state. The development and use of pregnancy-specific values are critical to the proper clinical interpretation of ROTEM in women with serious hemorrhage during different stages in pregnancy. TAT was the earliest laboratory marker for coagulation activation among others.

Evaluation and Management of Coagulopathies and Thrombophilias in Pediatric Patients

The diagnosis of coagulopathy or thrombophilia in pediatric patients can be challenging. Congenital coagulopathies often present in the pediatric period and require appropriate work-up for diagnosis and ongoing management. Acquired coagulopathies of childhood are frequently encountered in hospitalized children and warrant appropriate coagulation testing for goal-directed therapy. The incidence of thrombosis is increasing in pediatric patients. After identifying the presence of thrombus, acute management includes initiating therapeutic anticoagulation. Choice of anticoagulant depends on patient's clinical status, along with availability of the anticoagulant. Thrombophilia evaluation is performed when children present with spontaneous thrombosis. Thrombophilia tests are inaccurate during acute illness.

Low antithrombin levels in neonates and infants undergoing congenital heart surgery result in more red blood cell and plasma transfusion on cardiopulmonary bypass

BACKGROUND

Neonates have lower levels of antithrombin (AT) due to immature liver synthetic function. AT deficiency may lead to inadequate anticoagulation with heparin during cardiac surgery resulting in consumption of coagulation factors and increased blood transfusion. The goal of this study is to examine the effect of AT level on the transfusion requirements of neonates and infants undergoing open heart surgery.

STUDY DESIGN AND METHODS

This is a prospective, observational study at a tertiary pediatric referral center. Neonates and infants up to 6 months of age undergoing congenital heart surgery with cardiopulmonary bypass (CPB) were enrolled. Demographic, intraoperative, transfusion, and complications data were collected. Preoperative AT level was measured after induction of anesthesia. Prior to separation from CPB, a second blood sample was drawn and AT, thrombin antithrombin complex (TAT), D-dimer, and anti-Xa levels were measured. Linear and logistic regression were performed for data analysis.

RESULTS

Preoperative low AT level was significantly associated with increased transfusion of red blood cells (RBCs) and fresh frozen plasma (FFP) during CPB, but not after separation from CPB. The incidence of thrombosis and re-operation were not associated with preoperative AT levels. There was no association between TAT, D-dimer, and anti-Xa levels at the end of CPB and preoperative AT levels.

CONCLUSION

Low preoperative AT level is associated with increased transfusion of RBC and FFP on CPB in neonates and infants undergoing congenital heart surgery. Low preoperative AT level did not result in coagulation activation after CPB and after surgery.

C-reactive protein-induced activated partial thromboplastin time prolongation in heparinized samples is attenuated by elevated factor VIII

INTRODUCTION

Activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) activity are used to monitor unfractionated heparin therapy in children on extracorporeal membrane oxygenation (ECMO). Elevated C-reactive protein (CRP) can prolong aPTT and cause discrepancy between these two assays. We aimed to evaluate CRP effect on aPTT and anti-Xa assays in the presence of heparin and to determine whether elevated CRP affects laboratory monitoring in pediatric ECMO patients.

MATERIALS AND METHODS

Citrated normal specimens were spiked with CRP, heparin, and recombinant factor VIII (FVIII) and followed by measurement of aPTT and anti-Xa activity. Additionally, aPTT, anti-Xa activity, FVIII, fibrinogen, and CRP were measured in 18 ECMO specimens.

RESULTS

Elevated CRP prolonged aPTT in normal specimens with or without heparin, but did not affect anti-Xa assay. In contrast, ECMO specimens showed similar aPTT and anti-Xa values regardless of CRP level. Elevated CRP in specimens was accompanied by increased fibrinogen and FVIII activity. Additional in vitro experiments confirmed that FVIII spiked simultaneously with CRP attenuated CRP-induced aPTT prolongation in heparinized specimens.

CONCLUSION

In vitro CRP-induced aPTT prolongation is not observed in pediatric ECMO samples due to concomitant FVIII increase. Discordant changes of CRP and FVIII in plasma could contribute to aPTT/anti-Xa discrepancies observed during heparin therapy in the pediatric population. The anti-Xa assay is preferable for heparin monitoring in pediatric ECMO settings.

Structural characterization of a clinically described heparin-like substance in plasma causing bleeding

Heparin-like substances (HLS) have been described in various clinical situations, including in settings of liver disease associated with infection, transplant, and metastasis. HLS are generally attributed to circulating glycosaminoglycans. Initial results for this patient showed coagulopathy due to liver disease without HLS. Two weeks after liver transplantation, a 10 year-old female with liver failure patient began to bleed from catheter insertion sites, mouth, and nares and HLS was suspected. The patient subsequently died and these clinical samples resulted in the isolation of a single heparan sulfate (HS) present at high concentrations in the plasma. Analysis of this HS showed it had an intermediate between heparin and HS with low antithrombin-mediated anticoagulant activity. We speculate that this 10-year old patient might have a platelet function defect influenced by this unusual HS. Endothelial defects not measurable by our methods might have also contributed to the observed bleeding complications.

Hemostatic Management of Extracorporeal Circuits Including Cardiopulmonary Bypass and Extracorporeal Membrane Oxygenation

Cardiopulmonary bypass and extracorporeal membrane oxygenation (ECMO) cause hemostatic derangements that can predispose patients to both bleeding and thrombotic complications. Often, patients present for urgent surgery while taking medications including antiplatelet agents, vitamin K antagonists, and direct oral anticoagulants, which must be recognized, monitored, and managed. During extracorporeal circulation, appropriate anticoagulation, most commonly with heparin, is required to maintain blood flow and avoid thrombotic complications. However, anticoagulation and other effects of extracorporeal circuits can also have an undesired consequence of bleeding. Extracorporeal circulation leads to coagulopathy that may require therapy with blood products such as platelets, cryoprecipitate, and plasma in case a patient bleeds. Platelet dysfunction related to exposure to a foreign circuit is a primary concern, as is the development of acquired von Willebrand syndrome, which frequently remains undetected on routine testing. Hemorrhagic complications in ECMO, such as intracranial hemorrhage, pulmonary hemorrhage, and hemithorax, can occur. Hemostatic agents including antifibrinolytics, desmopressin, fibrinogen concentrates, and other factor concentrates may be needed to achieve hemostasis in these often-challenging patients. Managing bleeding on extracorporeal support requires careful monitoring and a thoughtful approach.

Maternal outcomes in unexpected placenta accreta spectrum disorders: single-center experience with a multidisciplinary team

OBJECTIVE

In a 2015 Maternal-Fetal Medicine Units Network study, only half of placenta accreta spectrum cases were suspected before delivery, and the outcomes in the anticipated cases were paradoxically poorer than in unanticipated placenta accreta spectrum cases. This was possibly because the antenatally suspected cases were of greater severity. We sought to compare the outcomes of expected vs unexpected placenta accreta spectrum in a single large US center with multidisciplinary management protocol.

STUDY DESIGN

This was a retrospective cohort study carried out between Jan. 1, 2011, and June 30, 2018, of all histology-proven placenta accreta spectrum deliveries in an academic referral center. Patients diagnosed at the time of delivery were cases (unexpected placenta accreta spectrum), and those who were antentally diagnosed were controls (expected placenta accreta spectrume). The primary and secondary outcomes were the estimated blood loss and the number of red blood cell units transfused, respectively. Variables are reported as median and interquartile range or number (percentage). Analyses were made using appropriate parametric and nonparametric tests.

RESULTS

Fifty-four of the 243 patients (22.2%) were in the unexpected placenta accreta spectrum group. Patients in the expected placenta accreta spectrum group had a higher rate of previous cesarean delivery (170 of 189 [89.9%] vs 35 of 54 [64.8%]; P < .001) and placenta previa (135 [74.6%] vs 19 [37.3%]; P < .001). There was a higher proportion of increta/percreta in expected placenta accreta spectrum vs unexpected placenta accreta spectrum (125 [66.1%] vs 9 [16.7%], P < .001). Both primary outcomes were higher in the unexpected placenta accreta spectrum group (estimated blood loss, 2.4 L [1.4-3] vs 1.7 L [1.2-3], P = .04; red blood cell units, 4 [1-6] vs 2 [0-5], P = .03).

CONCLUSION

Our data contradict the Maternal-Fetal Medicine Units results and instead show better outcomes in the expected placenta accreta spectrum group, despite a high proportion of women with more severe placental invasion. We attribute this to our multidisciplinary approach and ongoing process improvement in the management of expected cases. The presence of an experienced team appears to be a more important determinant of maternal morbidity in placenta accreta spectrum than the depth of placental invasion.

Coagulopathy in surgical management of placenta accreta spectrum

BACKGROUND

One of the major complications of the placenta accreta spectrum (PAS) is the development of coagulopathy. The detection, prevention and prompt treatment of coagulopathy may be lifesaving.

OBJECTIVE

Our objective was to study selected factors associated with coagulopathy in the management of PAS by a well-established multidisciplinary team.

STUDY DESIGN

This is a retrospective review of all patients with pathologically proven PAS (including placenta accreta, increta or percreta) who underwent surgery by our multidisciplinary team between January 2011 and February 2017. Coagulopathy in this setting was defined as a platelet count of <100,000/mm³, international normalized ratio >1.5, and/or fibrinogen <300 mg/dL based on institutional protocols developed by our Division of Transfusion Medicine & Coagulation. The outcomes of those patients with and without coagulopathy were compared with appropriate adjustments. Receiver operating characteristics curves (ROCs) were constructed to assess the ability of select variables to discriminate between women with and without coagulopathy, and the area under the curves (AUCs) were calculated.

RESULTS

Of 123 singleton patients with PAS, 37 (30.1%; 95%CI 22.1-39.0) developed coagulopathy and 86 (69.9%; 95%CI 61.0-77.9) did not. Baseline patient demographic characteristics did not differ significantly between these groups. Estimated blood loss (median and Inter-quartile range) was 2100cc (1800, 400) and 1400 (1000, 2500) in the presence and absence of coagulopathy, respectively (P < 0.01). The overall number of units of red blood cells (RBC) transfused was greatest in the coagulopathy group [3 (2, 9) vs. 1 (0, 4); P < 0.01]. Univariate regression analysis confirmed the association between coagulopathy and (i) the number of units of RBC's transfused, and (ii) the estimated blood loss. ROC curves showed that an estimated blood loss ≥ 1500 mL had the best discriminating power. Depth and/or severity of placental invasion were not associated with coagulopathy in patients with PAS.

CONCLUSIONS

Coagulopathy in patients with PAS undergoing hysterectomy is strongly associated with blood loss and replacement. It may be prudent to establish protocols that aggressively monitor for, and treat, coagulopathy when EBL exceeds 1500 mL in such surgeries, prior to the development of clinical coagulopathy which if uncorrected may lead to massive blood loss.

Coagulation and Bleeding Management in Pediatric Extracorporeal Membrane Oxygenation: Clinical Scenarios and Review

Extracorporeal membrane oxygenation (ECMO) is a life-saving procedure that requires careful coagulation management. Indications for ECMO continue to expand, leading to more complicated patients treated by ECMO teams. At our pediatric institution, we utilize a Coagulation Team to guide anticoagulation, transfusion and hemostasis management in an effort to avoid the all-to-common complications of bleeding and thrombosis. This team formulates a coagulation plan in conjunction with a multidisciplinary ECMO team after careful review of all available laboratory data as well as the patient's clinical status. Here, we present our general strategies for ECMO management in various clinical scenarios and a review of the literature pertaining to coagulation management in the pediatric ECMO setting.

Deficiency of complement factor H-related proteins and autoantibody-positive hemolytic uremic syndrome in an infant with combined partial deficiencies and autoantibodies to complement factor H and ADAMTS13

A 3-month-old male infant developed an extremely severe episode of atypical hemolytic uremic syndrome (aHUS) associated with partial deficiencies of full-length complement factor H (FH; ∼15% of infant normal) and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) (39% of normal) and autoantibodies reactive with both proteins. His FH and ADAMTS13 genes were normal, indicating that the partial deficiencies were acquired, probably as the result of autoantibodies against full-length FH and ADAMTS13. The child also had a homozygous deletion of the complement factor H–related (CFHR)3–CFHR1 portion in the complement factor H (CFH) gene cluster. He therefore had deficiency of CFHR proteins and autoantibody-positive hemolytic uremic syndrome (DEAP-HUS) with an unusual early onset associated with a partial deficiency of ADAMTS13 and an anti-ADAMTS13 autoantibody. His clinical episode of aHUS responded to plasma infusion and subsequent treatment with mycophenolate and rituximab. We believe that this is the first report of DEAP-HUS in an infant with partial deficiencies in both ADAMTS13 and full-length FH acquired in association with autoantibodies to both proteins.

ABO-incompatible deceased donor pediatric liver transplantation: Novel titer-based management protocol and outcomes

ABO-ILT have re-emerged as an alternate option for select patients awaiting transplant. However, treatment protocols for children undergoing deceased donor ABO-ILT are not standardized. We implemented a novel IS protocol for children undergoing deceased donor ABO-ILT based on pretransplant IH titers. Children with high pretransplant IH titers (≥1:32) underwent an enhanced IS protocol including plasmapheresis, rituximab, IVIG, and mycophenolate, while children with IH titers ≤1:16 received steroids and tacrolimus. We retrospectively assessed our outcomes of ABO-ILT with ABO-compatible recipients of similar age and diagnosis over a 2-year period. Ten children with median age of 8.9 months underwent ABO-ILT, 4 of 10 patients underwent enhanced IS due to high IH titers. Rates of complications (rejection, infections, biliary, and vascular) at both 1 year and up to 3 years post-transplant were comparable between the groups. Patients with ABO-ILT had good graft function with 100% survival at a median follow-up of 3.3 years. In conclusion, IS tailored to pretransplant IH titers in pediatric deceased donor ABO-ILT is feasible and can achieve outcomes similar to ABO-CLT at 1 and 3 years post-transplantation.

Management of Hemostasis for Pediatric Patients on Ventricular-Assist Devices

Ventricular-assist devices (VADs) have seen increased utilization in the pediatric population. Formerly, this therapeutic modality was limited to only the pulsatile VAD, EXCOR (Berlin Heart GmbH). However, the continuous flow VAD devices, HeartMate II (Abbott Inc.) and HeartWare (Medtronic Inc.), are now increasingly used in this population. Postoperatively, VAD patients are acutely anticoagulated using unfractionated heparin, often beginning 24 to 48 hours after VAD placement. Once the patient is stabilized and ready to transition to a lower acuity or outpatient setting, low-molecular-weight heparin or warfarin therapy may be instituted. Also, because of the risk for thrombotic and thromboembolic complications, antiplatelet strategies are employed using medications such as aspirin, clopidogrel, or dipyridamole. Platelet-rich plasma or whole blood platelet aggregation studies, platelet function analyzer-100 (Siemens), VerifyNow (Accriva Diagnostics), or thromboelastography platelet mapping (Haemonetics) may be used to help monitor antiplatelet effects, though the interpretation of the strength of the antiplatelet effect remains difficult. Care must be taken to monitor the hematologic complications of VAD, including acquired von Willebrand syndrome, which increases the risk for bleeding, and intravascular hemolysis, which increases the risk of thrombosis. Appropriate device placement and anticoagulation management are imperative to help avoid neurological dysfunction and ischemic stroke, the most devastating potential complications of VAD therapy. As our experience grows, we continue to gain an increased understanding of the management of anticoagulation, need for antiplatelet medication, and appropriate monitoring for these critical patients.

Bleeding and Thrombotic Complications in the Use of Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) has been used for >40 years to support lung and heart failure; however, bleeding and thrombosis remain serious complications. The known etiologies of bleeding include heparin effect or overdose, coagulopathy, thrombocytopenia, platelet dysfunction, acquired von Willebrand syndrome, and hyperfibrinolysis. Bleeding sites may include cannula insertion sites, recent surgical incisions, vascular access sites, lung, gastrointestinal tract, mouth, nose, thoracic cavity, abdominal cavity, and brain. Massive bleeding in the brain, the most feared bleeding complication, can be rapidly fatal because it occurs in a rigid closed space, is difficult to drain, and cannot be stopped with direct pressure to the bleeding site. Pulmonary hemorrhage may cause irreversible lung damage. Management should be swift and precise to prevent fatal bleeding. In contrast, etiologies of thrombosis include high fibrinogen and factor VIII levels, heparin resistance, and platelet activation. Achieving the optimal anticoagulation balance to prevent bleeding and thrombosis in ECMO patients is extremely complex. Experts in hemostasis should be a part of an institutional ECMO team and continuously available for immediate management.

Population pharmacokinetics of human antithrombin concentrate in paediatric patients

AIMS

Antithrombin is increasingly used in paediatric patients, yet there are few age-specific pharmacokinetic data to guide dosing. We aimed to describe the pharmacokinetic profile of human (plasma-derived) antithrombin concentrate in paediatric patients.

METHODS

A 5-year retrospective review was performed of patients <19 years of age admitted to our institution who received antithrombin concentrate, were not on mechanical circulatory support and had baseline (predose) and postdose plasma antithrombin activity levels available for analysis. Demographic and laboratory variables, antithrombin dosing information and data on the use of continuous infusion unfractionated heparin were collected. Population pharmacokinetic analysis was performed with bootstrap analysis. The model developed was tested against a validation dataset from a cohort of similar patients, and a predictive value was calculated.

RESULTS

A total 184 patients met the study criteria {46.7% male, median age [years] 0.35 [interquartile range (IQR) 0.07-3.9]}. A median of two antithrombin doses (IQR 1-4) were given to patients (at a dose of 46.3 ± 13.6 units kg^-1 ), with median of three (IQR 2-7) postdose levels per patient. Continuous infusion unfractionated heparin was administered in 87.5% of patients, at a mean dose of 34.1 ± 22.7 units kg^-1 h^-1 . A one-compartment exponential error model best fit the data, and significant covariates included allometrically scaled weight on clearance and volume of distribution, unfractionated heparin dose on clearance, and baseline antithrombin activity level on volume of distribution. The model resulted in a median -1.75% prediction error (IQR -11.75% to 6.5%) when applied to the validation dataset (n = 30).

CONCLUSIONS

Antithrombin pharmacokinetics are significantly influenced by the concurrent use of unfractionated heparin and baseline antithrombin activity.

Multidisciplinary team learning in the management of the morbidly adherent placenta: outcome improvements over time

BACKGROUND

Morbidly adherent placenta (MAP) is a serious obstetric complication causing mortality and morbidity.

OBJECTIVE

To evaluate whether outcomes of patients with MAP improve with increasing experience within a well-established multidisciplinary team at a single referral center.

STUDY DESIGN

All singleton pregnancies with pathology-confirmed MAP (including placenta accreta, increta, or percreta) managed by a multidisciplinary team between January 2011 and August 2016 were included in this retrospective study. Turnover of team members was minimal, and cases were divided into 2 time periods so as to compare 2 similarly sized groups: T1 = January 2011 to April 2014 and T2 = May 2014 to August 2016. Outcome variables were estimated blood loss, units of red blood cell transfused, volume of crystalloid transfused, massive transfusion protocol activation, ureter and bowel injury, and neonatal birth weight. Comparisons and adjustments were made by use of the Student t test, Mann-Whitney U test, χ² test, analysis of covariance, and multinomial logistic regression.

RESULTS

A total of 118 singleton pregnancies, 59 in T1 and 59 in T2, were managed during the study period. Baseline patient characteristics were not statistically significant. Forty-eight of 59 (81.4%) patients in T1 and 42 of 59 (71.2%) patients in T2 were diagnosed with placenta increta/percreta. The median [interquartile range] estimated blood loss (T1: 2000 [1475-3000] vs T2: 1500 [1000-2700], P = .04), median red blood cell transfusion units (T1: 2.5 [0-7] vs T2: 1 [0-4], P = .02), and median crystalloid transfusion volume (T1: 4200 [3600-5000] vs T2: 3400 [3000-4000], P < .01) were significantly less in T2. Also, a massive transfusion protocol was instituted more frequently in T1: 15/59 (25.4%) vs 3/59 (5.1%); P < .01. Neonatal outcomes and surgical complications were similar between the 2 groups.

CONCLUSION

Our study shows that patient outcomes are improved over time with increasing experience within a well-established multidisciplinary team performing 2-3 cases per month. This suggests that small, collective changes in team dynamics lead to continuous improvement of clinical outcomes. These findings support the development of centers of excellence for MAP staffed by stable, core multidisciplinary teams, which should perform a significant number of these procedures on an ongoing basis.

Stability and Sterility of Enoxaparin 8 mg/mL Subcutaneous Injectable Solution

BACKGROUND: Enoxaparin is often diluted to accurately deliver doses to neonatal and infant patients. Current recommendations for dilutions may not be adequate for the smallest patients. METHODS: Review of dosing at our institution occurred, and an 8 mg/mL concentration of enoxaparin was chosen. A concentration of 8 mg/mL was compounded by diluting 0.4 mL of enoxaparin (100 mg/mL) into 4.6 mL of sterile water for injection into an empty sterile vial. Four syringes of the 8 mg/mL concentration were prepared by 5 technicians (20 total syringes). Stability and sterility testing occurred a 0, 7, 14, and 30 days. One-way repeated-measures analysis of variance was used to detect significant differences in Anti-Factor Xa concentrations at the testing time points. RESULTS: The dilution of enoxaparin was sterile at 30 days but exhibited significant degradation at the 30-day point (p < 0.05). CONCLUSION: A dilution of enoxaparin 8 mg/mL is stable and sterile for 14 days refrigerated but is not stable at 30 days.