Evaluation of a diagnostic platelet aggregation test strategy for platelet rich plasma samples with low platelet counts.

INTRODUCTION: Light transmission aggregometry (LTA) is important for diagnosing platelet function disorders (PFD) and von Willebrand disease (VWD) affecting ristocetin-induced platelet aggregation (RIPA). Nonetheless, data is lacking on the utility of LTA for investigating thrombocytopenic patients and platelet rich plasma samples with low platelet counts (L-PRP). Previously, we developed a strategy for diagnostic LTA assessment of L-PRP that included: (1) acceptance of referrals/samples, regardless of thrombocytopenia severity, (2) tailored agonist selection, based on which are informative for L-PRP with mildly or severely low platelet counts, and (3) interpretation of maximal aggregation (MA) using regression-derived 95% confidence intervals, determined for diluted control L-PRP (C-L-PRP). METHODS: To further evaluate the L-PRP LTA strategy, we evaluated findings for a subsequent patient cohort. RESULTS: Between 2008 and 2021, the L-PRP strategy was applied to 211 samples (11.7% of all LTA samples) from 192 unique patients, whose platelet counts (median [range] × 109 /L) for blood and L-PRP were: 105 [13-282; 89% with thrombocytopenia] and 164 [17-249], respectively. Patient-L-PRP had more abnormal MA findings than simultaneously tested C-L-PRP (p-values <0.001). Among patients with accessible electronic medical records (n = 181), L-PRP LTA uncovered significant aggregation abnormalities in 45 (24.9%), including 18/30 (60%) with <80 × 109 platelets/L L-PRP, and ruled out PFD, and VWD affecting RIPA, in others. The L-PRP LTA strategy helped diagnose VWD affecting RIPA, Bernard Soulier syndrome, familial platelet disorder with myeloid malignancy, suspected ITGA2B/ITGB3-related thrombocytopenia, and acquired PFD. CONCLUSION: Diagnostic LTA with L-PRP, using a strategy that considers thrombocytopenia severity, is feasible and informative.

Prevalence and Risk Factors for Moral Distress in Pediatric Oncology Health Care Professionals.

PURPOSE: Moral distress (MoD) is prevalent among health care professionals (HCPs) in oncology and is associated with burnout. The objectives of this study were to quantify MoD among pediatric oncology healthcare professionals (HCPs) at a Canadian quaternary care hospital, identify root causes, and evaluate change over time. METHODS: Eligible pediatric oncology HCPs were identified, and consenting participants completed the Measure of Moral Distress-Healthcare Professionals (MMD-HP) and MoD Thermometer (MDT) at baseline, followed by biweekly MDTs over 12 weeks. RESULTS: A total of 139 HCPs participated. The mean MMD-HP score was 123 ± 57.0, range 9-288. Demographic risk factors identified for elevated MMD-HP scores were female sex (female 127.1 and male 83.6, P = .01) and nursing role (nurse 136.3 and most responsible physician 85.3, P = .02). Higher MMD-HP scores were found in HCPs who were currently considering resigning because of MoD compared with those who were not (169.9 v 115.4, P < .001). Situations involving administration of treatment to children with poor prognosis cancers that was perceived to be overly aggressive were ranked as the greatest environmental contributor to MoD. Baseline and mean MDT scores over time strongly correlated with MMD-HP scores (P < .0001 and P = .0003, respectively), with mean MDT scores showing no significant fluctuation over the 12-week period. CONCLUSION: MoD was common among pediatric oncology HCPs. Risk factors for elevated levels of MoD included both demographic and environmental factors. Implementation of systems to improve team communication and decision making, especially in the care of patients with poor prognosis cancers, may affect HCP MoD.

Rare inherited coagulation and fibrinolytic defects that challenge diagnostic laboratories.

BACKGROUND: Coagulation factors, anticoagulants, and fibrinolytic proteins are important for hemostasis, and mutations affecting these proteins causes some rare inherited bleeding disorders that are particularly challenging to diagnose. AIMS: This review provides current information on rare inherited bleeding disorders that are difficult to diagnose. MATERIAL & METHODS: A review of the literature was conducted for up to date information on rare and difficult to diagnose bleeding disorders. RESULTS: Some rare bleeding disorders cause an inherited deficiency of multiple coagulation factors (F), such as combined FV and FVIII deficiency and familial vitamin K-dependent clotting factor deficiency. Additionally, congenital disorders of glycosylation can affect a variety of procoagulant and anticoagulant proteins and also platelets. Some bleeding disorders reflect mutations with unique impairments in the procoagulant/anticoagulant balance, including those caused by F5 mutations that secondarily increase the plasma levels of tissue factor pathway inhibitor as well as THBD mutations that increase functional thrombomodulin in plasma or cause a consumptive coagulopathy due to thrombomodulin deficiency. Some bleeding disorders accelerate fibrinolysis due to loss-of-function mutations in SERPINE1 and SERPINF2 or in the case of Quebec platelet disorder, a duplication mutation that rewires PLAU and selectively increases expression in megakaryocytes, resulting in a unique platelet-dependent gain-of-function defect in fibrinolysis. DISCUSSION: Current information on rare and difficult to diagnose bleeding disorders indicates they have unique clinical and laboratory features, and pathogenic characteristics to consider for diagnostic evaluation. CONCLUSION: Laboratories and clinicians should consider rare inherited disorders, and difficult to diagnose conditions, in their strategy for diagnosing bleeding disorders.

Thromboelastography and thrombin generation assessments for pediatric severe hemophilia A patients are highly variable and not predictive of clinical phenotypes.

Background: Severe hemophilia A (SHA) patients vary in severity of bleeding, arthropathy, and requirements for replacement factor VIII (FVIII). Baseline hemostatic activity assays using calibrated automated thrombography (CAT) and thromboelastography (TEG) may offer insights into the physiological basis of clinical heterogeneity. Objectives: Use CAT and TEG to measure baseline hemostatic activity in a cohort of 30 pediatric SHA patients with available clinical data. Determine effect of contact activation inhibition with corn trypsin inhibitor (CTI). Assess heterogeneity among patients for baseline hemostatic activity and examine correlations between assay results and clinical parameters including FVIII dosing regimen, von Willebrand factor level, and Pettersson arthropathy score. Methods: SHA blood after FVIII washout was subjected to TEG, and platelet-rich (PRP) and platelet-poor plasma was used for CAT assays. Varying concentrations of tissue factor (TF) were used. Statistical analysis examined relationships between assay results, and clinical parameters. Results: CTI treatment was required to obtain TEG and CAT results representative of baseline hemostatic activity. Weak activity was observed in assays with low TF concentrations (0.5-2 pM), and most but not all samples approached normal activity levels at high TF concentrations (10-20 pM). A significant positive correlation was observed between results of TEG and CAT-PRP assays. Correlations were not detected between hemostatic assay results and clinical parameters. Conclusions: In vitro hemostatic assay results of samples containing platelets showed concordance. Assay results were not predictive of FVIII requirements or correlated with other clinical parameters. SHA patient heterogeneity is influenced by factors other than baseline hemostatic activity.

Performance of the McGill Interactive Pediatric OncoGenetic Guidelines for Identifying Cancer Predisposition Syndromes.

IMPORTANCE: Prompt recognition of a child with a cancer predisposition syndrome (CPS) has implications for cancer management, surveillance, genetic counseling, and cascade testing of relatives. Diagnosis of CPS requires practitioner expertise, access to genetic testing, and test result interpretation. This diagnostic process is not accessible in all institutions worldwide, leading to missed CPS diagnoses. Advances in electronic health technology can facilitate CPS risk assessment. OBJECTIVE: To evaluate the diagnostic accuracy of a CPS prediction tool (McGill Interactive Pediatric OncoGenetic Guidelines [MIPOGG]) in identifying children with cancer who have a low or high likelihood of having a CPS. DESIGN, SETTING, AND PARTICIPANTS: In this international, multicenter diagnostic accuracy study, 1071 pediatric (<19 years of age) oncology patients who had a confirmed CPS (12 oncology referral centers) or who underwent germline DNA sequencing through precision medicine programs (6 centers) from January 1, 2000, to July 31, 2020, were studied. EXPOSURES: Exposures were MIPOGG application in patients with cancer and a confirmed CPS (diagnosed through routine clinical care; n = 413) in phase 1 and MIPOGG application in patients with cancer who underwent germline DNA sequencing (n = 658) in phase 2. Study phases did not overlap. Data analysts were blinded to genetic test results. MAIN OUTCOMES AND MEASURES: The performance of MIPOGG in CPS recognition was compared with that of routine clinical care, including identifying a CPS earlier than practitioners. The tool's test characteristics were calculated using next-generation germline DNA sequencing as the comparator. RESULTS: In phase 1, a total of 413 patients with cancer (median age, 3.0 years; range, 0-18 years) and a confirmed CPS were identified. MIPOGG correctly recognized 410 of 412 patients (99.5%) as requiring referral for CPS evaluation at the time of primary cancer diagnosis. Nine patients diagnosed with a CPS by a practitioner after their second malignant tumor were detected by MIPOGG using information available at the time of the first cancer. In phase 2, of 658 children with cancer (median age, 6.6 years; range, 0-18.8 years) who underwent comprehensive germline DNA sequencing, 636 had sufficient information for MIPOGG application. When compared with germline DNA sequencing for CPS detection, the MIPOGG test characteristics for pediatric-onset CPSs were as follows: sensitivity, 90.7%; specificity, 60.5%; positive predictive value, 17.6%; and negative predictive value, 98.6%. Tumor DNA sequencing data confirmed the MIPOGG recommendation for CPS evaluation in 20 of 22 patients with established cancer-CPS associations. CONCLUSIONS AND RELEVANCE: In this diagnostic study, MIPOGG exhibited a favorable accuracy profile for CPS screening and reduced time to CPS recognition. These findings suggest that MIPOGG implementation could standardize and rationalize recommendations for CPS evaluation in children with cancer.

Glanzmann Thrombasthenia: Perspectives from Clinical Practice on Accurate Diagnosis and Optimal Treatment Strategies.

Glanzmann thrombasthenia (GT) is a rare autosomal recessive disorder of fibrinogen-mediated platelet aggregation due to a quantitative or qualitative deficit of the αIIbß3 integrin at the platelet surface membrane resulting from mutation(s) in ITGA2B and/or ITGB3. Patients tend to present in early childhood with easy bruising and mucocutaneous bleeding. The diagnostic process requires consideration of more common disorders of haemostasis and coagulation prior to confirming the disorder with platelet light transmission aggregation, flow cytometry of CD41 and CD61 expression, and/or exon sequencing of ITGA2B and ITGB3. Antifibrinolytic therapy, recombinant activated factor VII, and platelet transfusions are the mainstay of therapy, although the latter may trigger formation of anti-platelet antibodies in GT patients and inadvertent platelet-refractory disease. The management of these patients therefore remains complex, particularly in the context of trauma, labour and delivery, and perioperative care. Bone marrow transplantation remains the sole curative option, although the venue of gene therapy is being increasingly explored as a future alternative for definitive treatment of GT.

Successful treatment of non-midline primary malignant germ cell tumors with yolk sac components in neonates: report of 2 cases.

Here, the authors present 2 cases of nongerminomatous germ cell tumor (NGGCT): a neonate with a mixed malignant germ cell tumor, 5% yolk sac tumor (YST) and 95% immature teratoma components, originating from the right mesial temporal lobe; and a 2-month-old infant with a pure YST originating from the left middle cranial fossa. These tumors with yolk sac components, which are thought to have a poor prognosis, were successfully treated with complete tumor resection alone and subtotal tumor resection with chemotherapy, respectively. Event-free survival exceeds 5 years for each patient even though neither received radiotherapy. The authors highlight the role of radical surgery and the successful treatment of neonatal YST with aggressive resection (and chemotherapy in 1 case) while avoiding radiation therapy. They also report the very rare non-midline location of these neonatal NGGCTs and emphasize the importance of considering YSTs and mixed NGGCTs with YST components in the differential diagnosis of non-midline hemispheric or skull base tumors in newborns.

Retrospective evaluation of a decision-support algorithm (MIPOGG) for genetic referrals for children with neuroblastic tumors.

BACKGROUND: Neuroblastoma is the most common pediatric extracranial solid tumor. Germline pathogenic variants in ALK and PHOX2B, as well as other cancer predisposition genes, are increasingly implicated in the pathogenesis of neuroblastic tumors. A challenge for clinicians is the identification of children with neuroblastoma who require genetics evaluation for underlying cancer predisposition syndromes (CPS). PROCEDURE: We developed a decisional algorithm (MIPOGG) to identify which patients with neuroblastic tumors have an increased likelihood of an underlying CPS. This algorithm, comprising 11 Yes/No questions, evaluates features in the tumor, personal and family history that are suggestive of an underlying CPS. We assessed the algorithm's performance in a retrospective cohort. RESULTS: Two hundred and nine of 278 consecutive patients with neuroblastic tumors at The Hospital for Sick Children (2007-2016) had sufficient clinical data for retrospective application of the decisional algorithm. Fifty-one of 209 patients had been referred to genetics for CPS evaluation; 6/51 had a genetic or clinical confirmation of a CPS. The algorithm correctly identified all six children (Beckwith-Wiedemann (n = 2), Fanconi anemia, RB1, PHOX2B, chromosome duplication involving ALK) as requiring a genetic evaluation by using clinical features present at diagnosis. The level of agreement between the algorithm and physicians was 83.9%, with 15 more patients identified by the algorithm than by physicians as requiring a genetics referral. CONCLUSIONS: This decisional algorithm appropriately detected all patients who, following genetic evaluation, were confirmed to have a CPS and may improve the detection of CPS in patients with neuroblastic tumors compared with current practice.