The prevalence of bleeding disorders among healthy pediatric patients with abnormal preprocedural coagulation studies

Gingival bleeding is a useful clinical feature in the diagnosis of hereditary bleeding disorders in children

The search for hereditary bleeding disorders (HBD) prior to invasive procedures in children is primarily based on personal and family bleeding history. Although several scores are available, they have only been evaluated in specific situations or in adults. Our monocentric retrospective study aimed to analyze the association between clinical history and four scores (HEMSTOP, PBQ, ISTH-BAT, TOSETTO) and the diagnosis of MHC in children referred to the University Hospital of Montpellier for hemostasis investigations. A total of 117 children were retrospectively included in the study. Of these, 57 (49%) were diagnosed with HBD, with 30 having primary bleeding disorders and 27 having coagulation disorders. The diagnosis of HBD was significantly associated with gingival bleeding, which was present in 30% of HBD patients. In our population, only the HEMSTOP score showed an association with the diagnosis of HBD, but it was positive in only 48% of patients. By including gingival bleeding as a factor, we modified the HEMSTOP score, which increased its sensitivity from 0.45 to 0.53. When examining primary bleeding disorders, the modified HEMSTOP score, with the inclusion of gingival bleeding, enables us to diagnose 63% of patients (see Fig. 1).    Conclusion: Therefore, gingival bleeding should be considered a useful factor in bleeding history for HBD diagnosis. Adding this symptom to a screening score such as HEMSTOP improves its sensitivity. To confirm our findings, a prospective study is required.    Trial registration: Study registration number: NCT05214300. What is Known: • Screening for hereditary bleeding disorder diseases is a necessity and a challenge in children. • Minor disorders of primary hemostasis are the most common, but often escape standard coagulation tests. What is New: • Gingival bleeding is a frequent symptom that is easy to investigate and may point to a primary hemostasis disorder. • Adding the gingival bleeding item to a routine screening score such as HEMSTOP improves sensitivity.

International Council for Standardization in Haematology recommendations for laboratory measurement of factor VIII and FIX type I inhibitors

This guidance document has been prepared on behalf of the International Council for Standardisation in Hematology. The aim of the document is to provide guidance and recommendations on the measurement of factor VIII (FVIII) and factor IX (FIX) inhibitors. After an introduction on the clinical background and relevance of factor VIII and factor IX inhibitor testing, the following aspects of laboratory testing are included: screening for inhibitors, assay principle, sample requirements, testing requirements and interpretation, quality assurance, interferences and recent developments. This guidance document focusses on recommendations for a standardised procedure for the laboratory measurement of FVIII and FIX type I inhibitors. The recommendations are based on published data in peer-reviewed literature and expert opinion.

Does Abnormal Preoperative Coagulation Status Lead to More Perioperative Blood Loss in Spinal Deformity Correction Surgery?

This study aims to analyze the potential association between the preoperative coagulation status and perioperative blood loss in spinal deformity correction surgery. The preoperative coagulation status and estimated blood loss (EBL) during operation, postoperative wound drainage, and allogeneic transfusion during and after operation were recorded and analyzed. Among the 164 patients, 26 had a longer prothrombin time (PT), 13 had a lower fibrinogen level, 55 had a longer activated partial thromboplastin time (APTT), and 2 had a longer thrombin time (TT), and the platelet count (PLT) was all normal or higher than the normal level. The mean EBL per surgical level was 77.8 ml (range, 22–267 ml), and the mean drainage per surgical level was 52.7 ml (range, 7–168 ml). Fifty-five patients and 12 patients underwent allogeneic transfusion during and after the operation, respectively. The differences in EBL per surgical level, mean drainage per surgical level, the occurrences of allogeneic transfusion during and after operation between the patients with a longer PT, lower fibrinogen level, longer APTT or longer TT, and the normal controls were not significant (all P’s > 0.05). The Spearman correlation analysis showed that there was no correlation between PT, fibrinogen, APTT, TT or PLT with EBL per surgical level, mean drainage per surgical level, or allogeneic transfusion during and after the operation (all P’s > 0.05). The abnormal preoperative coagulation status but not hemophilia does not lead to more perioperative blood loss or a higher rate of perioperative allogeneic transfusion in spinal deformity correction surgery.

Detecting coagulopathy in pediatric patients with post-tonsillectomy hemorrhage

INTRODUCTION

Post-tonsillectomy hemorrhage (PTH) is a serious complication after a tonsillectomy. Utility of lab work at presentation for PTH was low. This study aims to determine the frequency and type of labs drawn at emergency department (ED) presentation and assess the incidence of uncovering a previously unidentified coagulopathy.

METHODS

A retrospective chart review was performed on pediatric patients who were seen in the ED after tonsillectomy at a tertiary care children's hospital from 2017 to 2019. Exclusion criteria were the following: no tonsillar bleed, history of known coagulopathy, treated by outside provider, ≥18 years old. Lab work included complete blood count (CBC), prothrombin time (PT), partial thromboplastin time (PTT), and von Willebrand factor (VWF).

RESULTS

364/723 (50.3%) patients met inclusion criteria. 179/364 (49.2%) patients were male and 309/364 (84.9%) patients were Caucasian. Average age at surgery was 8.12 years (SD = 4.0) and average post-operative day at presentation was 6 days (SD = 2.1). Operative control of bleed was performed in 68/364 (18.7%) patients. 334/364 (91.8%) patients had labs drawn in the ED. 64/334 (19.1%) patients were anemic (hemoglobin (Hgb) < 11), 46/334 (13.8%) patients had thrombocytosis (platelets>450,000), 10/334 (3.0%) had elevated PTT and 8/334 (2.4%) had elevated PT. Hematology was consulted in 14/364 (3.8%) patients of whom 6/14 were diagnosed with von Willebrand disease and 1/14 with factor VII deficiency. Aminocaproic acid was used in 8/364 (2.2%) patients due to elevated PTT in 3/8 and multiple episodes of bleeding in 5/8.3/364 (0.8%) patients needed a blood transfusion. No difference was found in incidence of abnormal lab work in patients who did and did not need operative control of bleed (p = .125). Of the 334 patients who had ED labs drawn, 7 (2.1%) had an uncovered coagulopathy.

CONCLUSION

Uncovering incidental coagulopathies is rare in patients who present with PTH. Though anemia was the most common abnormality noted, only a small percentage required transfusion, with all having abnormal vital signs. Thrombocytosis was the next common abnormality, and this can be seen in an inflammatory state. Developing algorithms is necessary to better guide appropriate lab work in patients who present with PTH and to provide optimal value of care to patients.

Post-Tonsillectomy Hemorrhage and the Diagnosis of Occult Pediatric Coagulopathies

OBJECTIVES/HYPOTHESIS

The primary objective of this investigation was to determine rates of abnormal coagulation panels and diagnoses of coagulopathies in children with post-tonsillectomy hemorrhage (PTH). Secondary objectives identified patient demographics and hemorrhage event characteristics that correlated with a coagulopathy diagnosis.

STUDY DESIGN

Case series with chart review.

METHODS

Patients requiring operative control of PTH at a tertiary children's hospital between 2015 and 2019 were included. Details of tonsillectomy procedures and hemorrhage events were reviewed along with screening labs for coagulopathy, referrals to hematology and bleeding disorder diagnoses.

RESULTS

There were 250 children included. Mean age was 8.8 years (95% CI: 8.2-9.4) and 53.6% were males. PTH events occurred at a median of postoperative day six (mean: 5.9, 95% CI: 5.4-6.3), and 14.8% occurred within 24 hours of surgery. In this series, 23 patients (9.2%) had a second PTH, and three (1.2%) had a third PTH. Single and multiple PTH patients were similar with respect to age, gender, postoperative day, and technique (P > .05). Screening coagulation panels were obtained on presentation in 67.8% of children with one PTH and abnormally elevated in 38.3%. All children with multiple PTHs had labs drawn with 34.8% having elevated levels. No child with a single PTH was diagnosed with a bleeding disorder. Conversely, 87.0% of children with multiple PTHs saw hematology and three (13.0%) were diagnosed with a bleeding disorder (P < .001).

CONCLUSIONS

Obtaining coagulation panels in pediatric patients presenting with PTH is rarely useful and diagnosing a coagulopathy is uncommon. However, among children with a second PTH, referral to hematology is reasonable as this group has a significantly higher, albeit small, incidence of undiagnosed bleeding disorders.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2069-E2073, 2021.

Utility of Perioperative Laboratory Tests in Pediatric Patients Undergoing Spinal Fusion for Scoliosis

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

We aimed to characterize the frequency of perioperative laboratory tests for posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and to assess whether test results affected clinical management.

SUMMARY OF BACKGROUND DATA

Perioperative laboratory tests for PSF including complete blood count, coagulation laboratory tests, basic metabolic panels (BMPs), and type and screen, are commonly ordered based on providers' discretion or existing order sets. Studies have shown unnecessary laboratory tests as financially and physically costly in adults; however, no studies have examined the necessity of common perioperative laboratory tests in pediatric spinal deformity surgery.

METHODS

Retrospective review of patients aged 10-18 years who underwent PSF for AIS at our center in the past three years. The clinical utility of perioperative laboratory tests was assessed based on detected incidence of anemia, blood transfusions, hematology/endocrinology/nephrology consultations, insulin administration, and postponed/canceled surgeries.

RESULTS

A total of 234 patients were included (mean age 14.4 ± 1.8 years, 75% female). Of 105 (44.9%) patients with preoperative coagulation laboratory tests, 21 (20%) had abnormal results; however, none had subsequent hematology consultations or canceled/postponed surgeries. Postoperatively, only 5 (2.1%) patients and 30 (12.8%) patients had hemoglobin values less than 8 g/dL on postoperative day (POD) 1 and 2, respectively. Multivariate analysis identified POD1 hemoglobin ≤9.35 g/dL as the only predictor of hemoglobin <8 g/dL on POD2. Overall, there were 8 (3.4%) indicated blood transfusions postoperatively. Costs of unnecessary laboratory tests averaged $95.27 (range $49.72 to $240.27) per patient.

CONCLUSIONS

Many perioperative laboratory orders may be unnecessary in pediatric spinal deformity surgery, subjecting patients to extraneous costs and needlesticks. In particular, preoperative coagulation laboratory tests, perioperative BMPs, and additional postoperative CBCs for those with hemoglobin >9.35 on POD1 may not be warranted.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Laboratory testing for factor VIII and IX inhibitors in haemophilia: A review

Inhibitors are antibodies directed against haemophilia treatment products which interfere with their function. Factor VIII (FVIII) inhibitors in haemophilia A and factor IX (FIX) inhibitors in haemophilia B are significant clinically when they require a change in a patient's treatment regimen. Their persistence may increase morbidity and mortality. Multiple laboratory tests are now available for detecting and understanding inhibitors in haemophilia. Inhibitors are traditionally measured by their interference in clotting or chromogenic factor assays. They may also be detected using immunologic assays, such as enzyme-linked immunosorbent assay or fluorescence immunoassay. Anti-FVIII or anti-FIX antibodies of IgG4 subclass best correlate with the presence of functional inhibitors. Improvements in inhibitor measurement have been recently introduced. Preanalytical heat treatment of patient specimens allows testing of patients without delaying treatment. Use of chromogenic and immunologic assays may aid in identification of false-positive results, which are frequent among low-titre inhibitors. Validated reagent substitutions can be used to reduce assay cost. New methods for defining assay positivity and reporting low-titre inhibitors have been suggested. Challenges remain in the areas of quality control, assay standardization, monitoring of patients undergoing immune tolerance induction therapy and testing in the presence of modified and novel treatment products.

The relevance of the coagulation screen before surgery

Coagulation testing has long been part of the routine assessment of the preoperative patient, with the aim of identifying those with a bleeding disorder who might suffer significant perioperative bleeding. Some of the issues surrounding this involve the low prevalence of bleeding disorders in the general population, and the implications of further testing for both the patient and the health-care system. Studies suggest that this practice is not evidence based and is considered to be outdated. Most guidelines now advise against routine coagulation screens before surgery, and instead recommend taking a thorough personal and family history of bleeding in order to determine the need for further investigations. This review analyses current evidence on this topic and provides a comprehensive view of the relevance of preoperative coagulation testing.

An RYR1 mutation associated with malignant hyperthermia is also associated with bleeding abnormalities

Malignant hyperthermia is a potentially fatal hypermetabolic disorder triggered by halogenated anesthetics and the myorelaxant succinylcholine in genetically predisposed individuals. About 50% of susceptible individuals carry dominant, gain-of-function mutations in RYR1 [which encodes ryanodine receptor type 1 (RyR1)], though they have normal muscle function and no overt clinical symptoms. RyR1 is predominantly found in skeletal muscle but also at lower amounts in immune and smooth muscle cells, suggesting that RYR1 mutations may have a wider range of effects than previously suspected. Mild bleeding abnormalities have been described in patients with malignant hyperthermia carrying gain-of-function RYR1 mutations. We sought to determine the frequency and molecular basis for this symptom. We found that some patients with specific RYR1 mutations had abnormally high bleeding scores, whereas their healthy relatives did not. Knock-in mice with the malignant hyperthermia susceptibility RYR1 mutation Y522S (MHS RYR1Y522S) had longer bleeding times than their wild-type littermates. Primary vascular smooth muscle cells from RYR1Y522S knock-in mice exhibited a higher frequency of subplasmalemmal Ca(2+) sparks, leading to a more negative resting membrane potential. The bleeding defect of RYR1Y522S mice and of one patient was reversed by treatment with the RYR1 antagonist dantrolene, and Ca(2+) sparks in primary vascular smooth muscle cells from the MHS RYR1Y522S mice were blocked by ryanodine or dantrolene. Thus, RYR1 mutations may lead to prolonged bleeding by altering vascular smooth muscle cell function. The reversibility of the bleeding phenotype emphasizes the potential therapeutic value of dantrolene in the treatment of such bleeding disorders.

Elevated prothrombin time on routine preoperative laboratory results in a healthy infant undergoing craniosynostosis repair: Diagnosis and perioperative management of congenital factor VII deficiency

•

Factor VII deficiency is a rare autosomal disorder with genotypic and phenotypic variability.

•

Preoperative lab evaluation should at a minimum consist of a hematocrit, platelet count, type and screen, and coagulation studies for high-risk surgeries.

•

Treatment of acute hemorrhage in factor VII deficient patients primarily consists of factor VII (FVII) replacement therapy.

Introduction

Congenital factor VII deficiency is a rare bleeding disorder with high phenotypic variability. It is critical that children with congenital Factor VII deficiency be identified early when high-risk surgery is planned. Cranial vault surgery is common for children with craniosynostosis, and these surgeries are associated with significant morbidity mostly secondary to the risk of massive blood loss.

Presentation of case

A two-month old infant who presented for elective craniosynostosis repair was noted to have an elevated prothrombin time (PT) with a normal activated partial thromboplastin time (aPTT) on preoperative labs. The infant had no clinical history or reported family history of bleeding disorders, therefore a multidisciplinary decision was made to repeat the labs under general anesthesia and await the results prior to incision. The results confirmed the abnormal PT and the case was canceled. Hematologic workup during admission revealed factor VII deficiency. The patient underwent an uneventful endoscopic strip craniectomy with perioperative administration of recombinant Factor VIIa.

Discussion

Important considerations for perioperative laboratory evaluation and management in children with factor VII deficiency are discussed. Anesthetic and surgical management of the child with factor VII deficiency necessitates meticulous planning to prevent life threatening bleeding during the perioperative period.

Conclusion

A thorough history and physical examination with a high clinical suspicion are vital in preventing hemorrhage during surgeries in children with coagulopathies. Abnormal preoperative lab values should always be confirmed and addressed before proceeding with high-risk surgery. A multidisciplinary discussion is essential to optimize the risk-benefit ratio during the perioperative period.

Ability of hemostatic assessment to detect bleeding disorders and to predict abnormal surgical blood loss in children: a systematic review and meta-analysis

BACKGROUND

Systematic preoperative coagulation testing is still widely used in children scheduled for surgery, although current guidelines recommend that a bleeding history should be the first choice for hemostatic assessment. We performed a systematic review with meta-analysis to evaluate the pertinence of bleeding questionnaire and screening laboratory testing to detect bleeding disorders (BDs) in children and to predict abnormal surgical blood loss.

METHODS

A search was conducted in PubMed, EMBASE, MEDLINE(R), Cochrane Central Register of Controlled Trials, Health technology Assessment, and all EBM Reviews (Cochrane DSR, ACP Journal Club, DARE, CCTR, CMR, HTA, and NHSEED and EBM Reviews) up to October 22, 2013. Prospective trials containing 20 children or more and any tests evaluating either the ability of the test to detect a congenital BD or the ability of the test to predict increased surgical blood loss were retained. The quality of the study was judged with the Cochrane Collaboration Tool and two investigators extracted data independently. Data were combined to calculate the pooled diagnostic odds ratio (DOR) and their 95% confidence intervals (CI 95%). I(2) statistics were used to assess statistics heterogeneity.

RESULTS

Data could be extracted from 16 studies. Best results for detecting a congenital abnormality at potential risk for increased surgical blood loss were obtained with the PFA-100 (DOR = 113.0; 95% CI, 22.6-566.2; I(2) = 0%) in two studies, followed by the bleeding time in two other studies (DOR = 110.7; 95% CI, 24.4-502.3; I(2) = 0%). With a high amount of heterogeneity, questionnaires showed disappointing performances (DOR = 7.9; 95% CI: 3.5-17.5; I(2) = 72.6%).

CONCLUSION

Current evidence does not identify a tool that adequately predicts BDs and/or abnormal surgical blood loss in children. Questionnaires currently available do not perform well. In the setting of a pediatric coagulation clinic, the PFA-100 has the highest chance of detecting a BD. This meta-analysis highlights the weakness of the literature regarding the prediction of perioperative bleeding due to congenital hemostatic disorders in children.

Preprocedural Coagulation Studies in Pediatric Patients Undergoing Percutaneous Intervention for Appendiceal Abscesses

The literature reports poor correlation between coagulation screening and prediction of bleeding risk in children. Our aim is to determine whether there is a role for coagulation studies in children undergoing percutaneous intervention for appendiceal abscesses. A retrospective review of 1805 patients presenting with a diagnosis of appendicitis from September 2008 to September 2013 was performed. Patients presenting with appendiceal abscess who underwent percutaneous intervention were selected for further review (n = 131). A total of 76 patients (58%) had normal coagulation studies, whereas 55 (42%) had elevated values. An international normalized ratio ≥ 1.3 was found in 26 patients. Patients with normal coagulation values had an incidence of bleeding of 1.3 per cent. In the abnormal coagulation group, 8 patients received fresh frozen plasma before intervention, whereas 47 did not. There was one hematoma noted in each group with an incidence of bleeding of 3.6 per cent. The overall incidence of hematoma was 2.3 per cent with no significant difference in bleeding risk between the normal and abnormal coagulation groups. In conclusion, although many patients are found to have elevated coagulation studies, most do not have bleeding complications after intervention. There is poor correlation between coagulation screening and postprocedural outcomes evidenced by the low risk of bleeding.

Getting there--working toward minimizing blood loss in scoliosis surgery

Ryan KM, O'Brien K, Reqan I, O'Byrne JM, Moore D, Kelly PM, et al. The prevalence of abnormal preoperative coagulation tests in pediatric patients undergoing spinal surgery for scoliosis. Spine J 2015;15:1217-22 (in this issue).

The prevalence of abnormal preoperative coagulation tests in pediatric patients undergoing spinal surgery for scoliosis

BACKGROUND CONTEXT

Multilevel spinal fusion surgery for deformity correcting spinal surgery in pediatric patients with scoliosis has typically been associated with significant blood loss. The mechanism of bleeding in such patients is not fully understood. Coagulation abnormalities, which may be associated with scoliosis, are thought to play a role.

PURPOSE

To document and compare the prevalence of preoperative coagulation abnormalities among patients with scoliosis attending a pediatric orthopedic department for spinal fusion surgery with patients attending for minor surgery.

STUDY DESIGN

An observational study. All patients were recruited from a pediatric tertiary referral center in Dublin, Ireland.

PATIENT SAMPLE

Coagulation profile results were prospectively collected over a 2-year period from 165 spinal surgery patients. In total, 175 patients were included in the non-scoliosis group. These patients attended the day ward for minor procedures and were recruited over a 4-month period.

OUTCOME MEASURES

The primary outcome measure was the coagulation profiles, which included prothrombin time, activated partial thromboplastin time (APTT), and thrombin time (TT). Levels of Coagulation Factors II, V, VII, and X were also recorded.

METHODS

All blood samples were sent to the haematology laboratory to establish the coagulation profile. The primary outcome was the presence of an abnormal coagulation screening test (if any of PT, APTT, or TT were abnormal). Prothrombin time, APTT, and TT were also analyzed as individual continuous variables, as well as Coagulation Factors II, V, VII, and X. Regression analysis was used to compare the coagulation profile of scoliosis patients with that of non-scoliosis patients. There were no outside funding sources or any potential conflict of interest associated with this study.

RESULTS

The scoliosis patients were more likely to have an abnormal preoperative screening test compared with non-scoliosis patients, with an odds ratio of 2.6. Further analysis showed statistically significant longer clotting times for patients with scoliosis compared with those without; PT (t=3.37, p=.001), APTT (t=4.26, p<.001), TT (t=4.52, p<.001). Of the coagulation factors analyzed, only factor X was significantly different in scoliosis patients compared with non-scoliosis controls (t=-4.41, p<.001).

CONCLUSIONS

Children with scoliosis have a higher prevalence of preoperative coagulation abnormalities compared with normal healthy patients.

Do children without a known bleeding tendency undergoing PICC placement require coagulation laboratory testing?

BACKGROUND

Obtaining basic hemostatic laboratory investigations prior to peripherally inserted central catheter (PICC) insertion remains controversial, even if the procedure is converted to a tunneled central venous line (CVL) placement.

OBJECTIVE

To determine the value of pre-procedural blood screening (hemoglobin level, platelet count, aPTT/INR) in hospitalized children without a known bleeding diathesis.

MATERIALS AND METHODS

This retrospective review included pediatric patients undergoing PICC insertion who had both laboratory screening and post-PICC hemoglobin level. Two cohorts (A: 0-3 months; B: >3 months-18 years) were analyzed for procedural major/minor bleeding.

RESULTS

Of 1,441 consecutive children identified during a 3-year period, 832 patients (226 in cohort A, 606 in cohort B) fulfilled the inclusion criteria. Overall, 36% (300/832) of the patients had at least one abnormal laboratory result. Only 0.2% (3/1,441) of patients required conversion to a central venous line. In cohort A no major bleeding occurred; the minor bleeding frequency was 30% (68/226). Neither abnormal laboratory results nor correction of abnormal laboratory results was associated with minor bleeding complications. The positive and negative predictive values (PPV/NPV) of having abnormal laboratory screening were 0.22 and 0.68, respectively. In cohort B the major bleeding frequency was 1% (6/606) but no patient required any blood transfusion; minor bleeding occurred in 29% (174/606). Neither abnormal laboratory results nor correction of abnormal laboratory results was associated with minor bleeding complications. The PPV and NPV of abnormal laboratory screening results were 0.24 and 0.72, respectively.

CONCLUSION

Pre-procedural blood screening did not predict bleeding in hospitalized children without a known bleeding diathesis undergoing PICC insertion. The rarity of major bleeding complications and need for conversion to a central venous line did not support a need for laboratory screening.

Diagnostic outcome of preoperative coagulation testing in children

The value of routine coagulation testing instead of bleeding history alone in children, to predict bleeding risk prior to tonsillectomy and adenoidectomy has been questioned. Our objectives are to identify the causes of abnormal PT and/or aPTT in these patients, and to determine whether routine preoperative coagulation testing is effective in identifying children with a clinically significant coagulation abnormality prior to undergoing a procedure. In this study, data were extracted by chart review for 854 patients referred to the pediatric hematology service at Stony Brook University for the evaluation of an elevated PT and/or aPTT on preoperative testing. Seven hundred and ninety two of 854 reviewed charts (92.7%) contained sufficient data for analysis. On repeat testing, 393 (49.6%) had a laboratory abnormality identified. A potentially significant coagulation abnormality was identified in 32 of 792 patients (4%). For the remaining 760 patients, the most common diagnosis was a lupus anticoagulant (n = 98, 24.6%) or a "presumed" lupus anticoagulant (n = 166, 41.6%). A positive personal or family bleeding history was documented in 268 patients (268/792 = 33.8%). Of these patients, only 107 (39.9%) had an abnormality identified on further work-up. Seventeen of the 32 patients with clinically significant bleeding disorders identified were found to have a positive bleeding history (17/32 = 53.1%). Routine preoperative coagulation testing identifies only a small number of children at increased risk for surgical bleeding. However, a "positive" bleeding history identifies only 60% of children found to have a clinically significant coagulation abnormality. Routine preoperative coagulation testing may serve as a useful adjunct to clinical history.

Pre-interventional haemostatic assessment: Guidelines from the French Society of Anaesthesia and Intensive Care

Recently the French Society of Anaesthesia and Intensive Care (Société Française d'Anesthésie et de Réanimation [SFAR]) issued recommendations for the prescription of routine preoperative testing before a surgical or non-surgical procedure, requiring any type of anaesthesia. Thirty clinical specialists performed a systematic analysis of the literature, and recommendations were then developed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. One part of these guidelines is dedicated to haemostatic assessment. The goal of pre-anaesthetic screening for congenital or acquired haemostatic disorders is to prevent perioperative haemorrhagic complications through appropriate medical and surgical management. Preoperative assessment of bleeding risk requires a detailed patient interview to determine any personal or family history of haemorrhagic diathesis, and a physical examination is necessary in order to detect signs of coagulopathy. Laboratory investigation of haemostasis should be prescribed, not systematically, but depending on clinical evaluation and patient history. Standard tests (prothrombin time, activated partial thromboplastin time, platelet count) have a low positive predictive value for bleeding risk in the general population. Patients with no history of haemorrhagic diathesis and no conditions liable to interfere with haemostasis should not undergo pre-interventional haemostasis testing. Conversely, the existence of a positive history or a disease that could interfere with haemostasis should be an indication for clinically appropriate testing.

Comparison of clot-based, chromogenic and fluorescence assays for measurement of factor VIII inhibitors in the US Hemophilia Inhibitor Research Study

BACKGROUND

Detection and validation of inhibitors (antibodies) to hemophilia treatment products are important for clinical care, evaluation of product safety and assessment of population trends.

METHODS

Centralized monitoring for factor VIII (FVIII) inhibitors was conducted for patients in the Hemophilia Inhibitor Research Study using a previously reported modified Nijmegen-Bethesda clotting assay (NBA), a chromogenic Bethesda assay (CBA) and a novel fluorescence immunoassay (FLI).

RESULTS

NBA and CBA were performed on 1005 specimens and FLI on 272 specimens. CBA was negative on 880/883 specimens (99.7%) with Nijmegen-Bethesda units (NBU) < 0.5 and positive on 42/42 specimens (100%) with NBU ≥ 2.0 and 43/80 specimens (53.8%) with NBU 0.5-1.9. Among specimens with positive NBA and negative CBA, 58.1% were FLI negative, 12.9% had evidence of lupus anticoagulant, and 35.5% had non-time-dependent inhibition. CBA and FLI were positive on 72.4% and 100% of 1.0-1.9 NBU specimens and 43.1% and 50.0% of 0.5-0.9 NBU specimens. FLI detected antibodies in 98.0% of CBA-positive and 81.6% of NBA-positive specimens (P = 0.004). Among 21 new inhibitors detected by NBA, five (23.8%) with 0.7-1.3 NBU did not react in CBA or FLI. Among previously positive patients with 0.5-1.9 NBU, 7/25 (28%) were not CBA or FLI positive. FLI was positive on 36/169 NBU-negative specimens (21.3%).

CONCLUSIONS

FVIII specificity could not be demonstrated by CBA or FLI for 26% of inhibitors of 0.5-1.9 NBU; such results must be interpreted with caution. Low titer inhibitors detected in clot-based assays should always be repeated, with consideration given to evaluating their reactivity with FVIII using more specific assays.

Prospective evaluation of a pediatric bleeding questionnaire and the ISTH bleeding assessment tool in children and parents in routine clinical practice

BACKGROUND

Diagnosing mild bleeding disorders (BDs) in children is difficult. Bleeding scores (BSs) have been proposed for obtaining standardized quantitative histories.

OBJECTIVES

To compare the Canadian pediatric bleeding questionnaire (PBQ) with the new ISTH bleeding assessment tool (ISTH BAT) for the determination of BS in a routine pediatric outpatient setting.

METHODS

One hundred children with a suspected BD were enrolled in this cross-sectional study. Bleeding scores were calculated for all children and their natural parents. For all children, extensive laboratory investigations were performed.

RESULTS

Based on laboratory tests, 56 children were diagnosed as having no BD, 11 were diagnosed with possible VWD, 12 with VWD 1, 11 with VWD 2, five with possible platelet defects, and five with mild factor deficiencies. Both questionnaires were able to discriminate between no BD and VWD (P = 0.0001), but the area under the receiver characteristics curve to detect any mild BD was only 0.76. Despite the inherited nature of the BD, a family score did not increase the ability to discriminate between no BD and VWD (P = 0.2052). There was no significant difference between the two tools used (P = 0.3253) or simple qualitative criteria, such as yes/no questions regarding bleeding (P = 0.3477).

CONCLUSIONS

The two tools translated into German did not differ substantially. Both were able to discriminate between no BD and a possible BD with acceptable accuracy. A BS of < 2 makes a BD unlikely. Simple qualitative criteria were similar; however, to allow comparison of studies and follow-up in patients over time, we recommend the ISTH BAT.

Prospective evaluation of the clinical utility of quantitative bleeding severity assessment in patients referred for hemostatic evaluation

BACKGROUND

Quantitative bleeding assessment tools (BATs) have been used to describe the severity of the bleeding phenotype in patients with von Willebrand disease.

OBJECTIVES

To evaluate the clinical usefulness of a BAT for the diagnosis of mild bleeding disorders (MBDs) in previously undiagnosed patients.

METHODS

We prospectively assessed 215 patients who were consecutively referred for evaluation of bleeding symptoms (n=71), abnormal laboratory clotting test results (n=105) or family investigation (n=39) at two second-level centers. The bleeding history was assessed by a young investigator who administered the BAT instrument, and also by a senior physician who independently evaluated the patient and made the final diagnoses. Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) were computed for a predefined bleeding score (BS) cut-off (BS of >3). Receiver operating characteristic curves were used to establish a diagnostic prediction rule.

RESULTS

Assuming the prevalence of MBD in the general population to be ∼1%, a normal BS (≤3) had a very high NPV (99.2%). The PPVs in patients referred for hemostatic or family evaluation at second-level clinics were estimated to be 71.0% and 77.5% (assuming MDB prevalences of 20% and 50%, respectively, in these settings). Measurement of BS in addition to activated partial thromboplastin time significantly increased the diagnostic efficiency of the BAT instrument (NPV of 99.6%).

CONCLUSIONS

BAT use improves the evaluation of patients with suspected MBD, and we propose its use in a clinical prediction guide based on BAT and activated partial thromboplastin time for the exclusion of patients with suspected MBD in a low-prevalence setting.

A cost-effectiveness analysis of coagulation testing prior to tonsillectomy and adenoidectomy in children

BACKGROUND

The American Society of Pediatric Otolaryngology recommends pre-operative coagulation testing only when indicated by history or physical exam. Nevertheless, many surgeons test all children scheduled for tonsillectomy and/or adenoidectomy (T&A). Studies of pre-operative screening have had conflicting results. A decision analysis model was constructed to address the costs and health outcome states of pre-operative screening strategies in children.

PROCEDURE

A 14-day Markov model evaluated three strategies: (1) test all children for coagulation disorders; (2) test only those children with a pertinent history; and (3) perform no pre-operative testing. A literature search and a review of national databases estimated probabilities, costs, and utility data. Parameters then were varied widely in sensitivity analyses. Using a societal perspective and a cycle length of 1 day, we compared the strategies based on total costs and quality-adjusted life years (QALYs).

RESULTS

Total costs for the strategies were $3,200 for testing all children, $3,083 for testing only those with a history finding, and $3,077 for not testing. Total utilities were 0.02579, 0.02654, and 0.02659 QALYs, respectively. Cost-effectiveness ratios were most sensitive to variation in the cost of post-operative care and the probability of post-operative bleeding. The strategy of not testing was dominant in all sensitivity analyses.

CONCLUSIONS

Our results demonstrate that not performing preoperative testing is the most cost-effective strategy. This was persistent in sensitivity analyses, indicating that the model was robust. These data may be helpful to institutions and organizations to formulate policies regarding pre-operative coagulation for children without previous diagnoses of bleeding disorders.

Coagulation concepts update

OBJECTIVE

Since the previous comprehensive radiology review on coagulation concepts that was done in 1990, many studies have been published in the medical and surgical literature that can guide the approach of a radiology practice. The purpose of this article is to provide an analysis of these works, updating the radiologist on proper use and interpretation of coagulation assessment tools, medications that modify the hemostatic system, and the use of transfusions prior to interventions.

CONCLUSION

The basic tools for coagulation assessment have not changed; however, results from subspecialty research have suggested ways in which the use of these tools can be modified and streamlined to safely reduce time and expense for the patient and the health care system.

Pediatric otolaryngologic manifestations of bleeding disorders

OBJECTIVE

In 1930, considering the diseases of the blood and lymphatic glands in relation to otolaryngology, Goldsmith and McGregor stated that "... the otolaryngologist has frequently to deal with bleeding from the nose and throat ...". After approximately 8 decades, in particular preoperatively, the use of universal coagulation screening in children is still controversial. Aim of the present review was to offer a concise but complete discussion of clotting disorders with pediatric otolaryngological interest recognizing: (i) vascular disorders, (ii) platelet disorders, (iii) disorders of coagulation, and (iv) thrombosis.

METHODS

An exhaustive review of literature was performed to investigate available data and evidences regarding pediatric otolaryngologic manifestations of bleeding disorders.

RESULTS/CONCLUSIONS

Modern otolaryngologists should be familiar with common bleeding disorders since many have head and neck manifestations. This knowledge allows the choice of appropriate pre-operative screening of surgical patients. The most important component of the preoperative assessment is the bleeding history that directs further laboratory evaluation. All otolaryngologic surgical procedures in children with bleeding disorders should be carried out with the close co-operation of the Haematology Department.

Evaluation of children with a suspected bleeding disorder applying the Impact-R [Cone and Plate(let) Analyzer]

BACKGROUND

A convenient screening test for children with bleeding symptoms before more labor-intensive diagnostic steps are taken would be of value. The Impact-R was designed in an attempt to analyse platelet function under near physiological conditions. Results are presented as surface coverage (SC, %) and average size (AS, microm(2)).

OBJECTIVE

In this cross-sectional retrospective study, we assessed the use of the Impact-R in the evaluation of children with a suspected bleeding disorder (BD).

METHODS

The hospital charts of 110 children referred to the coagulation laboratory were reviewed for personal and family bleeding history (BH) as well as results of the laboratory evaluation.

RESULTS

A laboratory 'diagnosable' BD (LBD) was found in 23 children (21%, 95% CI 14-30%). A diagnosis of LBD was associated with the severity of bleeding but not with family BH. By receiver-operating characteristic (ROC) curve analysis, the SC was superior to the AS for diagnosis of a LBD. The Impact-R was abnormal in 43/97 children (44.3%, 95% CI 34-55%). The predictive values of a normal and abnormal Impact-R were 96% (95% CI 92-97%) and 42% (95% CI 28-56%), respectively. When considering the personal and family BH, the post-test probability for LBD after a normal Impact-R was reduced from 20% to 3.5% (95% CI 2.5-7%).

CONCLUSIONS

A normal Impact-R test is highly effective in excluding LBDs. Yet, in case of an abnormal Impact-R test, further testing is needed. An algorithm that includes the personal and family BH and the results of a screening test may improve the diagnostic process. Prospective studies are now needed to confirm these findings.