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OBJECTIVE: To assess cognitive, behavioral, and adaptive functions in children and young adults with hemophilia treated according to contemporary standards of care. STUDY DESIGN: Evolving Treatment of Hemophilia's Impact on Neurodevelopment, Intelligence, and Other Cognitive Functions (eTHINK) is a US-based, prospective, cross-sectional, observational study (September 2018 through October 2019). Males (aged 1-21 years) with hemophilia A or B of any severity, with or without inhibitors, were eligible. Participants underwent neurologic examinations and age-appropriate neuropsychological assessments, including standardized tests/ratings scales of early development, cognition, emotional/behavioral adjustment, and adaptive skills. RESULTS: Five hundred and fifty-one males with hemophilia A (n = 433) or B (n = 101) were enrolled. Performance on cognitive tests was largely comparable with that of age-matched US population norms, although participants in certain age groups (4-5 and 10-21 years) performed worse on measures of attention and processing speed. Furthermore, adolescents and young adults and those with comorbid attention-deficit/hyperactivity disorder (ADHD; n = 64) reported more adaptive and executive function problems in daily life. Incidence of ADHD in adolescents (21%) was higher than expected in the general population. CONCLUSIONS: In general, males with hemophilia demonstrated age-appropriate intellectual, behavioral, and adaptive development. However, specific patient/age groups showed poorer attention performance and concerns for executive and adaptive development. This study established a normative data set for monitoring neurodevelopment in individuals with hemophilia and highlight the importance of screening and intervention for challenges with cognitive and adaptive skills in this population. CLINICAL TRIAL REGISTRATION: Evolving Treatment of Hemophilia's Impact on Neurodevelopment, Intelligence, and Other Cognitive Functions (eTHINK); NCT03660774; https://clinicaltrials.gov/ct2/show/NCT03660774.
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BACKGROUND: Pediatric venous thromboembolism has increased by 130%-200%, specifically in hospitalized children, and direct oral anticoagulants (DOACs) offer several therapeutic advantages. METHODS: This study aims to evaluate the real-world epidemiological and outcome data from a retrospective review of pediatric patients treated with DOACs from January 1, 2013 to December 31, 2022. In this single-center, IRB-approved study, 65 patients were identified and analyzed using SPSS statistical software, and a descriptive statistical analysis was conducted. RESULTS: Of the 65 patients, 37% were on apixaban, 61.5% were on rivaroxaban, and 1.5% were on dabigatran. Per the 2023 ISTH outcome definitions, one (2%) patient had a major bleeding episode, six (9%) had clinically relevant non-major bleeding, three (5%) patients had patient-important heavy menstrual bleeding (HMB), and one (1.5%) patient had minor bleeding. Seven (19%) of 37 postmenarchal patients had evidence of HMB. Six (9.2%) patients had recurrent venous thromboembolism while on a DOAC (one was on apixaban, and five were on rivaroxaban) and were transitioned to other forms of anticoagulation. CONCLUSION: Thus, bleeding rates after DOAC therapy are comparable to previous DOAC trials, as well as other anticoagulants in pediatrics. HMB is an important outcome measure and should continue to be investigated. This study reports a higher rate of recurrent thrombosis (9.2%) compared to other trials. However, this observation may be attributed to patients who had ongoing risk factors, as well as a longer duration of study follow-up. Additional multicentered outcome studies evaluating DOAC use in children are needed to determine long-term recurrence and HMB risks.
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Menorragia , Tromboembolia Venosa , Femenino , Humanos , Niño , Rivaroxabán/efectos adversos , Tromboembolia Venosa/tratamiento farmacológico , Tromboembolia Venosa/epidemiología , Anticoagulantes/efectos adversos , Hemorragia/inducido químicamente , Hemorragia/epidemiología , Hemorragia/complicaciones , Dabigatrán/efectos adversos , Menorragia/complicaciones , Piridonas/efectos adversos , Estudios Retrospectivos , Administración OralRESUMEN
The understanding of coronavirus disease 2019 (COVID-19) immune dysregulation is evolving. Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with alternations in both innate and adaptive immunity, probably caused by a complex interplay of genetics and environmental exposure with various triggers. A rare hematological complication of SLE as well as recently reported in an adult with COVID-19 is thrombotic thrombocytopenic purpura. We report a pediatric case with features suggestive of the multisystem inflammatory syndrome in children with coronary artery ectasia, thrombotic thrombocytopenic purpura, and new-onset SLE.
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COVID-19 , Lupus Eritematoso Sistémico , Púrpura Trombocitopénica Trombótica , Adulto , COVID-19/complicaciones , COVID-19/diagnóstico , Niño , Humanos , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/diagnóstico , Púrpura Trombocitopénica Trombótica/complicaciones , Púrpura Trombocitopénica Trombótica/diagnóstico , Síndrome de Respuesta Inflamatoria Sistémica/complicacionesRESUMEN
Current treatments in the field of haemophilia are changing the phenotype of many patients with severe haemophilia to that of mild haemophilia. Despite this improvement, those with mild-to-moderate haemophilia A and haemophilia B continue to experience unmet needs. Whereas some patients with mild-to-moderate haemophilia experience similar complications to those of patients with severe haemophilia, they possess several unique attributes. These include a challenging diagnosis and variability in bleeding symptoms and treatment needs. In addition, haemophilia is an under-recognized condition in women even though many women with mild-to-moderate haemophilia experience the same symptoms and complications as men with haemophilia. These women also have their own unique challenges with this disease. This supplement highlights many of the unmet needs in men and women with mild-to-moderate haemophilia. The conclusions of each of these papers reinforce the need for additional research and resources for this patient population.
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Hemofilia A , Hemofilia B , Femenino , Hemofilia A/complicaciones , Hemofilia B/complicaciones , Hemorragia/etiología , Humanos , Masculino , FenotipoRESUMEN
Venous thromboembolism has increasing significance in hospitalized pediatric patients. Patients who have life-threatening or limb-threatening thrombotic events require thrombolysis in addition to anticoagulation. In patients who show signs of heparin resistance or heparin-induced thrombocytopenia, it is imperative to identify alternative therapeutic options. We present a child in whom bivalirudin was used for systemic anticoagulation during catheter-directed thrombolysis along with tissue plasminogen activator (Alteplase® ) for the treatment of a near-occlusive organ-threatening thrombus. We also review the currently available literature on the use of combination therapy of an intravenous direct thrombin inhibitor with alteplase.
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Antitrombinas/uso terapéutico , Cateterismo/efectos adversos , Resistencia a Medicamentos/efectos de los fármacos , Heparina/efectos adversos , Fragmentos de Péptidos/uso terapéutico , Trombosis/tratamiento farmacológico , Activador de Tejido Plasminógeno/efectos adversos , Preescolar , Fibrinolíticos/efectos adversos , Hirudinas , Humanos , Masculino , Pronóstico , Proteínas Recombinantes/uso terapéutico , Terapia Trombolítica , Trombosis/patologíaRESUMEN
Almost all of what is known about neurologic and cognitive development in hemophilia derives from the Hemophilia Growth and Development Study, conducted during an era when treatment regimens and comorbidities differed significantly from the current environment. Results suggested hemophilia and human immunodeficiency virus had independent effects, and hemophilia negatively impacts academic achievement, attention, and behavior. The introduction of prophylaxis treatment in hemophilia has created the need for re-evaluation of the effects of hemophilia on neurodevelopment and cognition. We outline the Evolving Treatment of Hemophilia's Impact on Neurodevelopment, Intelligence, and Other Cognitive Functions (NCT03660774) study, which aims to meet this need.
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Desarrollo Infantil , Discapacidades del Desarrollo/etiología , Hemofilia A/complicaciones , Hemofilia A/patología , Neuropsicología , Niño , Discapacidades del Desarrollo/patología , Hemofilia A/psicología , Humanos , Desempeño PsicomotorRESUMEN
Acquired pure red cell aplasia and acquired amegakaryocytic thrombocytopenic purpura are rare in children. Similarly, clonal expansion of T-cell large granular lymphocytes is infrequently seen in pediatrics. Lipopolysaccharide-responsive beige-like anchor (LRBA) protein deficiency is a recently described immunodeficiency syndrome that has been associated with inflammatory bowel disease and autoimmune phenomena such as Evans syndrome. Here, we describe a patient with LRBA deficiency who developed acquired pure red cell aplasia and acquired amegakaryocytic thrombocytopenic purpura associated with expansion of clonal T-cell large granular lymphocytes. This has not been described in the literature previously and adds to the knowledge on the spectrum of manifestations of LRBA deficiency.
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Proteínas Adaptadoras Transductoras de Señales/deficiencia , Aplasia Pura de Células Rojas , Linfocitos T , Adolescente , Enfermedades de la Médula Ósea/complicaciones , Enfermedades de la Médula Ósea/genética , Enfermedades de la Médula Ósea/metabolismo , Enfermedades de la Médula Ósea/patología , Humanos , Masculino , Púrpura Trombocitopénica/complicaciones , Púrpura Trombocitopénica/genética , Púrpura Trombocitopénica/metabolismo , Púrpura Trombocitopénica/patología , Aplasia Pura de Células Rojas/complicaciones , Aplasia Pura de Células Rojas/genética , Aplasia Pura de Células Rojas/metabolismo , Aplasia Pura de Células Rojas/patología , Linfocitos T/metabolismo , Linfocitos T/patologíaRESUMEN
Acute promyelocytic leukemia (APL) is characterized by a heightened risk of coagulopathy with significant morbidity and mortality. Here we report our evaluation of presenting white blood cell (WBC) and the International Society on Thrombosis and Haemostasis (ISTH) disseminated intravascular coagulation (DIC) scoring system as markers for early death and nonlethal coagulopathy in pediatric APL. We evaluated 79 pediatric patients treated on a Children's Oncology Group phase III clinical trial. There were 4 early deaths and 13 nonlethal, clinically significant (grade III to IV) coagulopathy events during induction. Elevated presenting WBC was significantly associated with early death but not with both lethal and nonlethal coagulopathy events. An ISTH DIC score of ≥5 (the original ISTH criteria for overt DIC) was not associated with either early deaths or coagulopathy events. An ISTH DIC score threshold of 6, however, was significantly associated with early death (12% score ≥6 vs. 0% score <6) and with both lethal and nonlethal coagulopathy events (35% score ≥6 vs. 11% score <6). In pediatric APL patients, the presenting WBC is a marker for risk of early death. Although the ISTH score using a cutoff of ≥6 showed improved correlation with adverse coagulation events during induction, the sensitivity was only 70.6% (95% confidence interval, 44.0%-89.7%) and the specificity was 64.5% (95% confidence interval, 51.3%-76.3%). Thus, there is a strong need to identify other biomarkers that can predict APL-associated coagulopathy.
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Hemorragia , Leucemia Promielocítica Aguda , Trombosis , Adolescente , Biomarcadores/sangre , Niño , Preescolar , Supervivencia sin Enfermedad , Femenino , Hemorragia/sangre , Hemorragia/etiología , Hemorragia/mortalidad , Hemorragia/terapia , Humanos , Lactante , Leucemia Promielocítica Aguda/sangre , Leucemia Promielocítica Aguda/mortalidad , Leucemia Promielocítica Aguda/terapia , Recuento de Leucocitos , Masculino , Factores de Riesgo , Tasa de Supervivencia , Trombosis/sangre , Trombosis/etiología , Trombosis/mortalidad , Trombosis/terapiaRESUMEN
Glanzmann's thrombasthenia (GT) is a rare congenital bleeding disorder associated with decreased platelet aggregation due to qualitative/quantitative deficiencies of the fibrinogen receptor. Severe bleeding episodes and perioperative bleeding are typically managed with platelet transfusions, although patients can develop anti-platelet antibodies or experience clinical refractoriness. The GT Registry (GTR) was established to collect efficacy/safety data on hemostatic treatments for GT, including recombinant factor VIIa (rFVIIa). At the request of the United States Food and Drug Administration, three hematology experts evaluated platelet refractoriness, antibody status, and rFVIIa efficacy data on a case-by-case basis to support a potential indication for rFVIIa in GT. Adjudication included 195 patients with 810 events (619 severe bleeding episodes, 192 surgeries), and a consensus algorithm was developed to describe adjudicators' coding of refractoriness and antibody status based on treatment patterns over time. Most rFVIIa-treated events were in patients without refractoriness or antibodies. Adjudicators rated most rFVIIa-treated bleeding episodes as successful (251/266, 94.4%; rFVIIa only, 101/109, 92.7%; rFVIIa ± platelets ± other agents, 150/157, 95.5%); efficacy was consistent in patients with platelet refractoriness ± antibodies (75/79, 94.9%), antibodies only (10/10, 100.0%), and neither/unknown (166/177, 93.8%). Adjudicators also rated most rFVIIa-treated surgeries as successful (159/160, 99.4%; rFVIIa only, 65/66, 98.5%; rFVIIa ± platelets ± other agents, 94/94, 100.0%); efficacy was consistent in patients with platelet refractoriness ± antibodies (69/70, 98.6%), antibodies only (24/24, 100.0%), and neither/unknown (66/66, 100.0%). Unblinding the adjudicators to investigator efficacy ratings changed few assessments. Doses of rFVIIa were narrowly distributed, regardless of other hemostatic agents used.
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Plaquetas/inmunología , Factor VIIa/uso terapéutico , Hemorragia/tratamiento farmacológico , Hemorragia/etiología , Isoanticuerpos/inmunología , Procedimientos Quirúrgicos Operativos/efectos adversos , Trombastenia/complicaciones , Adolescente , Niño , Preescolar , Coagulantes/uso terapéutico , Quimioterapia Combinada , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Proteínas Recombinantes/uso terapéutico , Trombastenia/diagnóstico , Trombastenia/cirugía , Resultado del Tratamiento , Adulto JovenRESUMEN
Infantile hemangioma is a benign vascular neoplasm that spontaneously involutes over time. Management, when needed, consists of medications, laser treatment and surgical excision. We describe a 3-year-old girl who presented shortly after birth with diffuse cutaneous hemangiomas, hepatosplenomegaly with liver lesions, anemia, and acute heart failure. She was diagnosed with hepatic and cutaneous infantile hemangioma based on skin biopsy. She developed progressive pulmonary hypertension with numerous pulmonary nodules suspicious for pulmonary arteriovenous malformations. She was started on sirolimus and had significant improvement in her pulmonary hypertension and liver lesions. This report supports prior studies that sirolimus is effective for vascular anomalies including IH refractory to conventional therapy.
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Disqueratosis Congénita/terapia , Hemangioma/diagnóstico , Hemangioma/tratamiento farmacológico , Trasplante de Células Madre Hematopoyéticas , Sirolimus/uso terapéutico , Aloinjertos , Preescolar , Femenino , Hemangioma/terapia , Humanos , Hipertensión Pulmonar/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Cutáneas , Resultado del TratamientoRESUMEN
BACKGROUND: There are two upper-extremity deep venous thrombosis (UEDVT) cases after whole blood donation reported in the English medical literature. Three additional UEDVT cases after whole blood donation were reported to our blood center within a 13-month period. STUDY DESIGN AND METHODS: A case study was done for each case in collaboration with a clinical physician. A description of the donation event, donor demographics, risk factors for thrombosis, treatment, and outcome were described. RESULTS: A 33-year-old woman and two 17-year-old, first-time-donating men presented with arm pain, swelling, and bruising within hours to 3 days after donation. Two had distal UEDVTs in the basilic or brachial veins, and one had a proximal UEDVT in the subclavian and axillary veins extending into the basilic vein. One donor (woman) had known risk factors for DVT and the other two did not. Anticoagulant therapy was initiated on all patients and was continued for 3, 4, and 9 months. Two donors with the distal UEDVTs recovered completely while the donor with the proximal UEDVT was treated with anticoagulation for 9 months and continued to have a slight residual, nonobstructive thrombosis. The donor was switched to low-dose aspirin prevention. The two donors reported in the literature had complete resolution of thrombosis. CONCLUSIONS: Four of five donors recovered completely after anticoagulation treatment for UEDVT, including two of three donors in this study. A review of all cases in the medical literature, including 20 recent Australian cases described in an abstract, provides a more complete description of this adverse donation injury.
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Donantes de Sangre , Flebotomía/efectos adversos , Trombosis Venosa Profunda de la Extremidad Superior/etiología , Adolescente , Adulto , Androstenos/efectos adversos , Anticonceptivos Hormonales Orales/efectos adversos , Sustitución de Medicamentos , Urgencias Médicas , Enoxaparina/uso terapéutico , Etinilestradiol/efectos adversos , Femenino , Humanos , Masculino , Regiones Promotoras Genéticas/genética , Protrombina/genética , Trombofilia/genética , Trombosis Venosa Profunda de la Extremidad Superior/tratamiento farmacológico , Trombosis Venosa Profunda de la Extremidad Superior/epidemiología , Trombosis Venosa Profunda de la Extremidad Superior/genética , Warfarina/uso terapéuticoRESUMEN
Oral contraceptive (OCP) induced changes on coagulation are complex with high inter-individual variability. The precise reason for differences in this variability is unknown. We hypothesized that global coagulation assays better delineate these changes and variability in hypercoagulability may be the result of differences in estrogen metabolism and thrombophilia. Fifty-two adolescents initiating OCPs were prospectively enrolled; 33 subjects completed the study. Samples were analyzed prior to and after OCPs for procoagulant and anticoagulant factor activities and thrombin generation (TG) +/-thrombomodulin. Participants were genotyped for common thrombophilia and estrogen receptor-α (ESR-α) single nucleotide polymorphisms (SNPs). SNP genotypes were compared to coagulation parameters; TG parameters and differences pre and post OCPs were examined. At baseline, a striking finding was elevated FVIII levels. FVL was absent in all and F2 G20210A was present in one participant. The ESR-α polymorphism was present in heterozygous state in 59% and homozygous state in 21% participants. There were no differences in VWF levels and FVIII: C after being on OCPs. Protein S levels decreased with OCPs. Sixty percent of participants showed evidence of hypercoagulability on TG testing on OCPs. Higher thrombin peak and endogenous thrombin potential (ETP) were seen on TG after OCPs. With thrombomodulin, ETP and thrombin peak did not decrease after OCPs, signifying 'thrombomodulin resistance'. We demonstrated that OCPs induce a state of "variable" hypercoagulability in adolescents, predominantly through the protein S pathway. Genetic and nongenetic factors may account for the variable increase in hypercoagulability. Further research is needed to understand this.
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Anticonceptivos Orales/efectos adversos , Receptor alfa de Estrógeno/genética , Etinilestradiol/efectos adversos , Norgestrel/análogos & derivados , Polimorfismo de Nucleótido Simple , Trombofilia/sangre , Adolescente , Coagulación Sanguínea/efectos de los fármacos , Pruebas de Coagulación Sanguínea , Factor V/genética , Factor V/metabolismo , Factor VIII/genética , Factor VIII/metabolismo , Femenino , Expresión Génica , Heterocigoto , Homocigoto , Humanos , Norgestrel/efectos adversos , Proteína S/genética , Proteína S/metabolismo , Trombina/metabolismo , Trombomodulina/sangre , Trombofilia/inducido químicamente , Trombofilia/genética , Adulto Joven , Factor de von Willebrand/genética , Factor de von Willebrand/metabolismoRESUMEN
Primary myelofibrosis is rare in children. Many causes have been described for secondary myelofibrosis including vitamin D deficiency. Here, we describe a patient with myelofibrosis secondary to vitamin D deficiency, as diagnosed by laboratory evidence. The patient also developed resultant extramedullary hematopoiesis with secondary development of ascites as a result of myelofibrosis. These are findings rarely reported in association with vitamin D deficiency. Potential mechanisms are also discussed.
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Hematopoyesis Extramedular , Hígado , Mielofibrosis Primaria , Deficiencia de Vitamina D , Ascitis/etiología , Ascitis/metabolismo , Ascitis/patología , Ascitis/fisiopatología , Femenino , Humanos , Lactante , Hígado/metabolismo , Hígado/patología , Hígado/fisiopatología , Mielofibrosis Primaria/etiología , Mielofibrosis Primaria/metabolismo , Mielofibrosis Primaria/patología , Mielofibrosis Primaria/fisiopatología , Deficiencia de Vitamina D/complicaciones , Deficiencia de Vitamina D/metabolismo , Deficiencia de Vitamina D/patología , Deficiencia de Vitamina D/fisiopatologíaRESUMEN
The incidence of pediatric pulmonary embolism (PE) has increased by 200 % in the last decade, but at a single center, it is still infrequent. Given the unique epidemiologic features of pediatric PE, diagnosis is often delayed, and the management is empiric, based on individual physician experience or preference. Thus, there is a strong need for center-specific uniform management of pediatric PE patients. In adults, the development of pulmonary embolism response teams (PERTs) or PE critical care pathways has shortened the time to diagnosis and the initiation of definitive management. Evidence to support an improvement in PE outcomes after the development of PERTs does not exist in children. Nonetheless, we have summarized the practical practice guidelines that physicians and institutions can adopt to establish their institutional PERTs or critical pathways. We also provide strategies for resource-challenged institutions for partnering with centers with expertise in the management of pediatric PE.
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Embolia Pulmonar , Adulto , Humanos , Niño , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/terapia , Cuidados CríticosRESUMEN
BACKGROUND: The pediatric emergency department (ED) management of bleeding and other complications of hemophilia constitutes an increasingly important component of hemophilia therapy. This retrospective study examined the overall ED use by children with hemophilia in a single center, with a particular aim to investigate visits related to injury or bleeding, and those related to blood stream infection in patients with a central venous catheter (CVC). METHODS: Electronic medical records of patients with hemophilia presenting to Children's Hospital of Michigan ED were reviewed. Different categories of ED visits over a 5-year period (January 2006-December 2010) were examined. RESULTS: There were 536 ED visits from 84 male patients (median age 4 years, range 0-21) with hemophilia over the 5-year period. The reasons for ED visits were: injury or bleeding (61.2%); suspected CVC-related infection (11.8%); causes unrelated to hemophilia (19.2%); and routine clotting factor infusion (7.8%). Eighteen visits from six patients were secondary to injury or bleeding in a patient not yet diagnosed with hemophilia. An intracranial hemorrhage was detected in five visits. Overall, 5.4% of all visits represented distinct episodes of bloodstream infection. CONCLUSION: The pediatric ED is an indispensable component of the overall hemophilia care, because: (1) patients with potentially lethal problems such as ICH or CVC-related infection may present to the ED for their initial management; (2) previously undiagnosed patients with hemophilia may also present to the ED for their first bleeding episodes, initiating the diagnostic investigations; (3) the ED provides after-hours treatment service for many episodes of injury or bleeding, and also for clotting factor infusion.
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Servicio de Urgencia en Hospital/estadística & datos numéricos , Hemofilia A/complicaciones , Adolescente , Infecciones Relacionadas con Catéteres/epidemiología , Infecciones Relacionadas con Catéteres/etiología , Niño , Preescolar , Femenino , Hemorragia/epidemiología , Hemorragia/etiología , Humanos , Lactante , Recién Nacido , Masculino , Estudios Retrospectivos , Adulto JovenRESUMEN
AIM: To evaluate fluctuations in anti-Xa concentrations in infants treated with enoxaparin for thrombosis and describe clinical outcomes. METHODS: A retrospective chart review was performed on infants treated with enoxaparin in the Neonatal Intensive Care Unit, and data on enoxaparin doses, anti-Xa concentrations, clinical characteristics and outcomes were abstracted. RESULTS: Our cohort (n = 26) had a median gestation of 36 (range, 23-41) weeks, birthweight of 2522 (510-3912) grams and 5-min Apgar score of 8(4-9). Fifteen (57.7%) infants were males. Thromboses was diagnosed at a median age of 22 (range, 1-97) days; enoxaparin was initiated at 27.5 (range, 4-98) days at a mean (SD) dose of 1.4 (0.3) mg/kg every 12 h. Therapeutic anti-Xa concentrations (0.5-1 U/mL) were achieved at a mean (SD) dose of 2.1 (0.6) mg/kg at 12.5 (12.2) days of treatment. Of the 143 anti-Xa concentrations, 39 (27%) were within the therapeutic range. During maintenance therapy following initial therapeutic anti-Xa concentration, 40% concentrations were therapeutic. Minor bleeding was noted in four infants and intracranial bleed in one infant; four infants died. During treatment, thrombocytopenia, renal and hepatic impairment during treatment were noted in 7, 2 and 4 infants, respectively. Clot resolution was observed in 21 (81%) infants. CONCLUSIONS: Anti-Xa concentrations fluctuate during maintenance enoxaparin therapy, with therapeutic levels being achieved only sporadically in young infants. Despite this, enoxaparin appears efficacious in thrombosis resolution. Further studies on the impact of stringent control of concentrations on outcomes in this population are warranted.