Performance Assessment of Anti-Xa Assay-Based Heparin Dosing Protocol in Pediatric Patients on Extracorporeal Membrane Oxygenation.

BACKGROUND: The use of extracorporeal membrane oxygenation (ECMO) in the postoperative cardiac critical care setting is evolving. Anticoagulation monitoring is among the most challenging aspects of pediatrics. However, there is no consensus on the optimal dosing and monitoring of unfractionated heparin in this setting. To address this, we developed an anti-Xa assay-based protocol derived from the best available clinical and anecdotal evidence of ECMO use and assessed its effectiveness in achieving the anti-Xa assay therapeutic target. METHODS: This prospective single-arm study was conducted in the pediatric carcardiac-surgery intensive care unit of a large tertiary hospital. We used two different anti-Xa assay intensity levels based on the patients' bleeding status. RESULTS: The median patient age was 7 (interquartile range [IQR]: 5-11.25) months, and the median weight was 5.7 (IQR: 3.8-13.82) kg. The median ECMO duration was 6 (IQR: 4.5-7.5) days. The bleeding protocol was used for most patients. Seventy percent achieved the anti-Xa assay therapeutic target during the study period (median: 75.5 h, IQR: 60.5-117.5 h). Hemorrhagic complications were reported in 40% of the patients, and thrombotic complications were reported in 25%. The median length of stay was 37 (IQR: 22-43) days, with a survival-to-discharge rate of 75%. CONCLUSIONS: Despite a failure to achieve the anti-Xa assay target within the first ECMO days, most patients achieved the target by the median ECMO duration. Moreover, using two different anti-Xa assay levels reduced thrombotic complications.

Prevalence of bleeding symptoms among young adults in Saudi Arabia, a national survey.

ABSTRACT: Prevalence of bleeding disorders vary due to several factors including geographical location. Mild bleeding disorders can lead to iron deficiency, morbidity, and in severe cases mortality. Quantification of haemorrhagic symptoms is a key component in management of bleeding disorders and a challenging task for clinicians.An abridged version of MCMDM-1vWD questionnaire with validated Arabic translation was used to quantify bleeding disorders in adult students (n = 1138) in 4 different regions of Kingdom of Saudi Arabia. Statistical analysis was performed to indicate gender disparity and prevalence.74.5% of respondents answered at least 1 question with affirmation, with 32.3% affected in Riyadh showing the highest prevalence and 14.03% affected in Dammam showing the least prevalence (P-value < .001). Gender-wise, higher prevalence of bleeding disorders in females 54.9% than in males 45.1% was observed (P-value .01). Epistaxis prevalence was significantly higher in males 30.7% vs 23.2% in females (P-value .0004), while cutaneous symptoms were reported significantly more by female participants 29.7% vs 12.3% in males (P-value < .001). Menorrhagia was reported by 28% of females, with heavy bleeding experienced by 57.6% female participants for <7 days while in 42.4% of females for >7 days.The current study signifies the ethnic distribution and gender disparity of mild bleeding disorders, and highlights the need for national surveillance system in order to improve management of patients with bleeding disorders.

Assessing the Performance of Extended Half-Life Coagulation Factor VIII, FC Fusion Protein by Using Chromogenic and One-Stage Assays in Saudi Hemophilia A Patients.

BACKGROUND: The one-stage assay is the most common method to measure factor VIII activity (FVIII : C) in hemophilia A patients. The chromogenic assay is another two-stage test involving purified coagulation factors followed by factor Xa-specific chromogenic substrate. AIM: This study aimed to assess the discrepancy and correlation between the chromogenic and one-stage assays in measuring FVIII : C levels in hemophilia patients receiving Extended Half-Life Elocta® as a recombinant extended half-life coagulation factor. METHODS: We performed a study comparing the measurements of FVIII : C levels by the chromogenic versus the one-stage assays at different drug levels. Data of FVIII : C levels, dosage, and the time interval from administration to measurement were retrieved from the hospital records. The correlation, mean differences, and discrepancy between the two assays were calculated. The linear regression analysis was used to predict the time interval till reaching 1% FVIII : C. RESULTS: Fourteen patients with 56 samples were included in the study. Of them, 13 patients were receiving Elocta® as a prophylactic, while one was receiving Elocta® on demand. One-third of these samples showed a discrepancy between the chromogenic and one-stage assays. The two assays were well correlated. Mean differences were significant at the individual and the time interval level. The time since the last Elocta® injection could significantly predict FVIII : C levels (ß = 0.366, P < 0.001). CONCLUSION: Our findings suggested a significant difference between both methods; the FVIII : C levels measured by the one-stage assay were less than those estimated by the chromogenic assay. However, the measurements of FVIII levels by the two assays were well correlated but discrepant in one-third of the samples. The levels of FVIII : C reach 1% after 5.4 days since the last Elocta® administration.

Prevalence of Coagulation Factors Deficiency among Young Adults in Saudi Arabia: A National Survey.

Introduction Inherited bleeding disorders vary in prevalence due to genetic disparity and ethnicity. Little is known about the prevalence of coagulation factor deficiency and bleeding disorders in middle-eastern population. Methods Young Saudi adults with at least one positive bleeding symptom reported in semi-structured validated condensed MCMDM-1vWD questionnaire were tested for complete blood count, routine and special coagulation tests, serum ferritin level, and capillary zone electrophoresis. After initial testing, those with prolonged prothrombin time (PT) or activated prothrombin time (APTT) had further testing to evaluate coagulation factors level. Platelet function was tested through platelet function analyzer (PFA)-100, and multiplate aggregometer (MEA) on patients suspected of having platelet disorders. Results Six-hundred-forty patients (male = 347, 54.2%) were included. A possible platelet function defect was diagnosed in three patients with one matching Glanzmann's thrombasthenia trait pattern, and one that of Bernard-Soulier trait pattern. One patient was diagnosed with von Willebrand disease. Deficiencies in coagulation factor levels were revealed as F-VIII in 14 (7.4%), F-IX in 15 (7.6%), F-II in two (3.3%), F-V in 17 (26.1%), FVII in two (3.1%), and F-X in one (1.8%) of study subjects; low vWF activity (<50%) was found in 14 (8%). Abnormal values were found for various laboratory tests with prolongation of platelet function analyzer-epinephrine (PFA-EPI) in 11%, PFA-ADP or arachidonic acid in 15.2%, PT in 35.9%, and APTT in 63.7%. Five-hundred-seventy-six patients (90%) had normal results in the coagulation factor assays and were categorized as patients with bleeding of unknown cause (BUC). A diagnosis of a bleeding disorder was more frequently made in men than in women (38 vs. 26). Iron deficiency anemia was found in 18 (25%) females positively associated with F-IX deficiency ( p -value 0.000). Male gender (73.3%, p = 0.007) was independently associated with the diagnosis of coagulation factor deficiency. Conclusion The current study reports a higher prevalence of coagulation factors deficiency in Saudi population than reported in the western population.

Clinical characteristics and outcome of children with biphenotypic acute leukemia.

BACKGROUND: Knowledge concerning the clinical and biological presentation, as well as the outcome of treatment, of biphenotypic acute leukemia in children is limited. DESIGN AND METHODS: This retrospective review analyzes the clinical features and outcome of children with biphenotypic acute leukemia diagnosed and treated over an 8-year period. According to the EGIL scoring system 24 (3.7%) of 633 patients with acute leukemia were classified as having biphenotypic acute leukemia. The diagnostic work-up and results were reviewed specifically for this study in the light of the newly published WHO criteria for the diagnosis of leukemia of ambiguous lineage. Based on these criteria, 11 (1.7%) patients were categorized according to the new nomenclature as having mixed phenotype acute leukemia. The majority of the patients (58.3%) had a B-lymphoid/myeloid phenotype, followed by the T-lymphoid/myeloid phenotype. The most frequent chromosomal abnormality involved the 14q32 locus. Patients received therapy based on a treatment regimen for acute lymphocytic leukemia regimen, which included myeloid-effective agents. RESULTS: At a median follow up of 4 years (range, 6 month - 7 years) the overall survival rate was 75.7% and the event-free survival rate was 73.5%. The survival of those patients who underwent hematopoietic stem cell transplantation in first complete remission was not different from that of the patients who were treated with chemotherapy alone (overall survival: 70.1% versus 81.1%, respectively, p=0.39; event-free survival: 70.1% versus 76.2%, respectively, p=0.75). The outcome of the 11 patients who were retrospectively classified as having mixed phenotype acute leukemia according to the new WHO criteria was excellent, with no relapses or deaths occurring among these patients. CONCLUSIONS: An acute lymphocytic leukemia type of induction therapy, using agents that are active against lymphoid and myeloid leukemias, appears to be more effective in achieving and maintaining complete remissions regardless of whether the patients are classified according to EGIL criteria or the new WHO criteria. Hematopoietic stem cell transplantation may not be necessary for all patients in first complete remission.

First description of the molecular and clinical characterization of hereditary factor V deficiency in Saudi Arabia: report of four novel mutations.

Coagulation factor V plays a significant role in the blood coagulation cascade as part of the prothrombinase complex. Factor V deficiency (FVD) is a rare autosomal recessive bleeding disorder with a variable phenotypic expression which varies from being asymptomatic-to-severe bleeding episodes. The aim of this study was to perform molecular and clinical characterization of FVD in patients originating from Saudi Arabia. Eleven patients (two males and nine females) with confirmed FVD were recruited in the study with ages ranging between 5 and 53 years. A next-generation sequencing-based hematology panel encompassing 393 known genes was used. A total of six sequence variations in F5 gene were identified, including four missense mutations (p.Pro189Leu, p.Trp2004Arg, p.Met2148Thr, p. Arg2202Cys), a deletion (p.Arg872Lysfs*12) and a splicing variant (c.1118+5G>T). Four variants were identified for the first time in this study. Three patients were homozygous for their respective mutations and seven patients were heterozygous. We were not able to identify a pathogenic variant in one patient of the cohort. In-silico and three-dimensional structural analyses were performed to predict the possible impact and functional consequences of the identified variants. To our knowledge, this is the first study addressing factor V mutations in patients with Arab ancestry. Results have helped in providing a definitive diagnosis to the patients and carrier detection in extended family members. Overall, the hematology panel assay was an efficient platform, demonstrating a formidable approach for the molecular diagnosis of other suspected bleeding disorders.

Identification of six novel factor viii gene variants using next generation sequencing and molecular dynamics simulation.

Hemophilia A is an X-linked recessive hemorrhagic disorder caused by variants in the F8 gene. To identify known and novel causative variants in hemophilia A, we have carried out genetic analysis among Saudi patients. Twenty-one patients, who were negative for inv-1/inv-22, were selected for analysis by next generation sequencing, thereafter confirmed by Sanger sequencing. In addition, the functionality and structural changes in the variant proteins were assessed using Molecular dynamics (MD) simulation and compared with wild-type and native proteins. In the samples we analyzed, we found 10 variants in 12 individuals; among them, five were novel and five were previously reported. The novel variants were located at positions: c.6130_6131insC, c.5815G>C, c.5493C>G, c.3734_3740delinsATTTCT and c.3744A>T. With the exception of one variant which was silent, the MD simulation revealed that the observed variants were causing severe structural changes when compared to the native protein and resulted in a loss of the protein's function. The MD analysis is in line with clinical data of patients who had <1% Factor VIII levels (severe hemophilia) with episodic bleeding, and were on more than one treatment. Moreover, some patients presented with chronic joint disability. These results will enrich the spectrum of variants and enlarge the factor VIII protein's database in the Saudi Arabian population.

Knowledge and attitude toward the hemoglobinopathies premarital screening program in Saudi Arabia: population-based survey.

Genetic screening is an important tool to control, minimize, and prevent genetic disorders. Saudi Arabia started the first national premarital screening (PMS) program to control inherited hemoglobin (Hb) disorders that are the most commonly inherited genetic disorders in the Kingdom of Saudi Arabia. The aim of this study was to assess the knowledge, perception, and attitude among the Saudi population about the PMS program through a questionnaire-based survey. A total of 1,047 candidates were included, divided into three groups. Group A represented the general population, group B was composed of couples presenting for PMS, and group C represented couples who had received their results. There was a fair knowledge among participants of the three groups about the nature of the tests and the targeted disorders, with more than 80% believing that it should include both sexually and genetically transmitted diseases. The concept of genetic counseling was liked by most of the participants. There was a positive attitude toward the program and the majority agreed to apply the PMS program to all couples in all country regions. More than 60% of all the participants were in favor of preventing at-risk marriages.

The Saudi Clinical Practice Guideline for the treatment of venous thromboembolism. Outpatient versus inpatient management.

Venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism (PE) is commonly encountered in daily clinical practice. After diagnosis, its management frequently carries significant challenges to the clinical practitioner. Treatment of VTE with the inappropriate modality and/or in the inappropriate setting may lead to serious complications and have life-threatening consequences. As a result of an initiative of the Ministry of Health of the Kingdom of Saudi Arabia, an expert panel led by the Saudi Association for Venous Thrombo-Embolism (a subsidiary of the Saudi Thoracic Society) and the Saudi Scientific Hematology Society with the methodological support of the McMaster University Guideline working group, this clinical practice guideline was produced to assist health care providers in VTE management. Two questions were identified and were related to the inpatient versus outpatient treatment of acute DVT, and the early versus standard discharge from hospital for patients with acute PE. The corresponding recommendations were made following the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.

A novel splice site mutation in the WAS gene causes Wiskott-Aldrich syndrome in two siblings of a Saudi family.

We report here on a Saudi family with two affected males with Wiskott-Aldrich syndrome (WAS), which includes mild to moderate bleeding and a low platelet count. A novel splice donor-site mutation (811 + 5 G <-- C) in intron 8 of the WAS gene (Genbank accession number NM_000377) was detected in a hemizygous status in both index cases, heterozygous in their mother and absent in the father. RNA from both index cases was transcribed and amplified with primers complementary to sequences in exons 7 and 10. A reverse transcription-polymerase chain reaction (RT-PCR) product of 688 bp (approximately 82%) was produced in addition to the normal RT-PCR product of 485 bp (approximately 18%). cDNA sequence analysis reveals an inclusion of full intron 8 sequence in the final transcript. The resultant protein is predicted to have 68 missense codons and a pre-mature stop codon at amino acid 260. This novel splice donor-site mutation was not detected in 80 normal controls (56 females and 24 males) from the same ethnic background as the index cases. Since no other mutation was detected in the WAS gene and the patients have classical symptoms of WAS, we concluded that it is highly likely that this novel mutation is responsible for the phenotype observed in these patients.

Donor lymphocyte infusion. An adaptive cellular immunotherapy for treatment of hematological malignancies.

The application of immunotherapy in the treatment of hematological malignancies is relatively new. Donor lymphocyte infusion (DLI) is a form of adaptive cellular therapy where the transfer of cells from immunocompetent donor to patient with cancer who relapsed after bone marrow transplantation results in destruction of the malignant cells. Hereby, we review the concepts, mechanisms, and results of the application of DLI in treatment of some hematological malignancies.

Megakaryocytic blast crisis at presentation in a pediatric patient with chronic myeloid leukemia.

Patients with chronic myeloid leukemia (CML) infrequently present in blast crisis (BC). While most BC are of myeloid origin, megakaryocytic BC is rare, especially at the time of CML diagnosis. We describe the first pediatric patient presenting with megakaryocytic leukemia and having BCR-ABL1 translocation as the single chromosomal abnormality. Clinical features were more suggestive of CML in megakaryocytic blast crisis than Philadelphia chromosome positive de novo AML. The patient was treated with AML-directed chemotherapy and imatinib mesylate followed by umbilical cord blood stem cell transplantation. The patient was in complete molecular response 16 months after stem cell transplantation.

Molecular genotyping of hemophilia A in Saudi Arabia: report of 2 novel mutations.

Different types of mutations have been reported in patients with hemophilia A. Although about half of all severe factor VIII deficiencies are caused by gene rearrangements (inversions) involving intron 22 in F8, other mutations such as point mutation, large deletions and insertions had been reported. We report the result of the first molecular testing for or F8 mutations from Saudi Arabia. A cohort of 22 men with hemophilia A was studied for F8 mutations. All patients were tested for factor VIII coagulant activity and inhibitors. Peripheral blood samples were used for DNA extraction followed by PCR detection of intron 22 inversion and all samples tested negative were screened for other F8 mutations. The patient's age ranged between 4 and 37 years. All patients except two siblings had severe hemophilia A. Only two patients out of 22 developed inhibitors with no obvious relation to the genotype. F8 Intron 22 inversion was detected in 10 patients (50%) of severe cases. Additionally, five point mutations and one deletion/insertion involving different exons were detected. All identified mutations were associated with severe phenotype except for one, which was associated with mild phenotype of hemophilia. This is the first report of molecular genotype of hemophilia A in the Saudi population and one of the few for Arab population. We had confirmed the incidence of Inversion 22 in severe hemophilia. We are reporting two novel mutations in F8, which can be used for carrier detection and prenatal genetic diagnosis (PGD).

Expression of CD66c and CD25 in acute lymphoblastic leukemia as a predictor of the presence of BCR/ABL rearrangement.

BACKGROUND: Expression of myeloid or T cell lymphoid in precursor B cell acute lymphoblastic leukemia (pre-B cell ALL), which is referred to as aberrant expression, is quite a common phenomenon. CD66c is a myeloid marker which has aberrant expression in pre-B cell ALL, with strong correlation with non-random genetic changes (BCR/ABL rearrangement). Another leukemia associated marker (CD25) is frequently expressed in pre-B cell ALL. The frequency of CD25-expressing lymphoblasts has been found to be significantly higher in BCR/ABL-positive vs. BCR/ABL-negative patients. METHODS: In a cohort of 103 patients diagnosed with pre-B cell ALL or biphenotypic leukemia and studied for expression of CD66c and CD25 at presentation, we evaluated the frequency of expression of either or both in BCR/ABL positive cases. RESULTS: Surface CD66c was expressed by 70 cases (68%) and CD25 was expressed by 33 cases (32%) while both were expressed together on 29 cases (28%). BCR/ABL was positive in 18/103 patients. All BCR/ABL positive cases were positive for surface CD66c and CD25. CONCLUSION: Positivity for both leukemia-associated antigens CD66c and CD25 in combination can predict the presence of BCR/ABL rearrangement in pre-B cell ALL. While this finding does not replace the detection of BCR/ABL abnormality by cytogenetic or molecular techniques, it does provide an early and handy tool for prediction and management of high-risk cases of pre-B cell ALL, especially in centers with limited laboratory facilities.

Hemoglobin D/beta-thalassemia and beta-thalassemia major in a Saudi family.

The present report describes the clinical, hematological and molecular characteristics in a family with unique interaction between 3 different mutations discovered during routine workup for bone marrow transplantation. In this report, complete hematological and molecular studies were performed for a large Saudi family. The family consisted of parents and 9 children, which revealed that the father is compound heterozygous for hemoglobin Hb D Punjab/beta-thalassemia, the mother is a carrier for beta-thalassemia and 3 of their children are transfusion dependent beta-thalassemia. Two of the children are compound heterozygous for Hb D Punjab/beta-thalassemia like the father but with different genotype. The other 2 children have Hb D Punjab traits while 2 other children have beta-thalassemia traits. Although, compound heterozygous for Hb D/beta-thalassemia has been well described in the literature, our report emphasizes the importance of careful analysis of the electrophoresis results and the usefulness of molecular studies in premarital screening and other screening hemoglobinopathy programs.

The evolving role of monoclonal antibodies and dendritic cell therapy in hematologic malignancies.

The approach for treatment of hematological cancers had changed in the last decade from non-specific eradication of tumor cells by chemotherapy to more specific strategies by activation of immune system. There are number of potential targets of immune responses in patients with hematological malignancies. Some have been developed like monoclonal antibody therapy and others that have yet to be define like dendritic cell infusion. In this review, we will discuss the evolving role of monoclonal antibody therapy and donor dendritic cell infusion in mounting on immune response in hematological malignancies.

Single center review of clinicopathological characterization in 77 patients with positive lupus anticoagulant antibodies.

BACKGROUND: The antiphospholipid syndrome (APS) is a thrombophillic disorder characterized by the presence of antiphospholipid antibodies (APA). It often occurs in patients with systemic lupus erythematosus (SLE) and may be associated with recurrent abortions and thrombocytopenia and, occasionally, catastrophic thrombotic events. OBJECTIVES: To examine, retrospectively, the clinico-pathological features of patients with APS detected by the presence of the lupus anticoagulant (LAC). METHODS: Patients were selected for study on the basis of a positive LAC test on review of the laboratory computer records of the King Faisal Specialist Hospital and Research Center. Following this, a clinical chart review was conducted in order to determine the clinical presentations, treatment and the course of patients identified. The information obtained was entered into an electronic database and subsequently analyzed. RESULTS: Seventy-seven patients were identified and reviewed. Fifty-six (73%) were female and 16 (21%) were children less than 15-years-old. Thirty-two patients (42%) had no clinical events (incidental APS). The syndrome was classified as primary in 40 (52%) patients and secondary in 37 (48%). Out of the 45 (58%) patients who presented with symptoms related to APA 22 (49%) had thrombosis, 24 (53%) had pregnancy failure, and 4 (9%) presented with catastrophic APS. The activated partial thromboplastin time (aPTT) was elevated and not corrected by mixing with normal plasma in 47 (61%). On the other hand, the prothrombin time (PT) was normal in 66 (90%). There is a significant difference between aPTT and PT as a screening test with P value of < 0.0001. Tests for anticardiolipin antibodies (ACA) were positive in 39 patients (70%). Only 13 (17%) patients had thrombocytopenia. All patients who presented with thrombosis were treated with warfarin but only 5 (23%) had received aspirin. Out of the 22 patients presenting with thrombosis, 12 (55%) had one or more recurrent thrombotic events while only 6 (25%) out of the 24 patients who presented with pregnancy failure had events other than pregnancy failure. Fifty-two patients were followed up regularly and were alive. CONCLUSIONS: We find that thrombosis, venous or arterial, and obstetric complications are the most frequent clinical findings in our patients with circulating LAC. Incidental APS is not an uncommon finding in patients screened for APS. There is a clear association between the presence of LAC and an abnormal aPTT, which is much less obvious with the PT.