Venous thromboembolic events in pediatric patients. Diagnosis and management

Use of rotational thromboelastometry to predict hemostatic complications in pediatric patients undergoing extracorporeal membrane oxygenation: A retrospective cohort study

BACKGROUND

The incidence of hemostatic complications in pediatric patients undergoing extracorporeal membrane oxygenation (ECMO) is high. The optimal anticoagulation strategy in children undergoing ECMO is unknown.

OBJECTIVES

To study the association between hemostatic complications, coagulation tests, and clinical parameters in pediatric patients undergoing ECMO and their effect on survival.

METHODS

We performed a retrospective cohort study of pediatric patients undergoing centrifugal pump ECMO. Collected data included patient characteristics, risk factors, and coagulation test results. Statistical analysis was done using logistic regression analysis for repeated measurements. Dependent variables were thrombosis and bleeding, independent variables were rotational thromboelastometry (ROTEM), activated partial thromboplastin time (aPTT) and antifactor-Xa assay (aXa) results, ECMO duration, age <29 days, sepsis and surgery.

RESULTS

Seventy-three patients with 623 ECMO days were included. Cumulative incidences of thrombosis and bleeding were 43.5% (95% confidence interval [CI], 26.0%-59.8%) and 25.4% (95% CI, 13.4%-39.3%), respectively. A lower maximum clot firmness of intrinsic ROTEM (INTEM; odds ratio [OR], 0.946; 95% CI, 0.920-0.969), extrinsic ROTEM (OR, 0.945; 95% CI, 0.912-0.973), and INTEM with heparinase (OR, 0.936; 95% CI, 0.896-0.968); higher activated partial thromboplastin time aPTT; OR, 1.020; 95% CI, 1.006-1.024) and age <29 days (OR, 2.900; 95% CI, 1.282-6.694); surgery (OR, 4.426; 95% CI, 1.543-12.694); and longer ECMO duration (OR, 1.149; 95% CI, 1.022-1.292) significantly increased thrombotic risk. Surgery (OR, 2.698; 95% CI, 1.543-12.694) and age <29 days (OR 2.242, 95% CI 1.282-6.694) were significantly associated with major bleeding. Patients with hemostatic complications had significantly decreased survival to hospital discharge (P = .009).

CONCLUSION

The results of this study help elucidate the role of ROTEM, aPTT, anti-factor Xa, and clinical risk factors in predicting hemostatic complications in pediatric patients undergoing ECMO.

Thrombosis Prevention and Anticoagulation Management in the Pediatric Patient with Congenital Heart Disease

Thrombosis is one of the most frequent complications affecting children with congenital heart disease (CHD). Palliative and reparative cardiac surgeries are some of the main players contributing to the thrombosis risk in this patient population. Additional risk factors related to the CHD itself (e.g., cardiac dysfunction, arrhythmias, and polycythemia in cyanotic cardiac disorders) can contribute to thrombogenicity alone or combined with other factors. Thrombotic complications have been recognized as a significant cause of morbidity and mortality in this patient population. Here, we provide an overview of the pathophysiology and risk factors for thrombosis as well as the indications for and use of different anticoagulation, antiplatelet, and thrombolytic agents. In addition, we describe some of most common thrombotic complications and their management in the pediatric CHD population.

Deep Venous Thrombosis in Teen With Crouzon Syndrome Post-Le Fort III Osteotomy With Rigid External Distraction

Venous thromboembolic events are rare in pediatric patients. Risk factors associated with the development of venous thromboembolic events in pediatric patients include the use of central venous catheters, hospitalization, cancer, sepsis, trauma, surgery, and congenital prothrombotic disorders.The authors present the case of a 14-year-old man with Crouzon syndrome who required Le Fort III osteotomy with rigid external distraction for significant midface hypoplasia who presented postoperatively with an extensive deep venous thrombosis. This is the first reported case of symptomatic venous thrombosis post-Le Fort III osteotomy and rigid external distraction. Although rare, surgeons should be aware of this potential complication.

Hematology and Oncology in Critical Illness

This chapter will focus on a variety of hematologic issues pertinent to the care of critically ill children. This is an area of intense research with the pathophysiology underlying these clinical conditions becoming progressively better understood. This improved understanding has resulted in new therapeutic strategies that are being assessed in multicenter clinical trials. The chapter will begin by describing the incidence and pathophysiologic significance of anemia in the pediatric intensive care unit (PICU) providing a differential diagnosis of the many conditions that may present with anemia in this setting. The chapter will next consider disseminated intravascular coagulation (DIC) focusing on the pathophysiology of a condition that has been associated with much morbidity and mortality. The underlying conditions predisposing to DIC will be detailed as well as a number of treatment options that have been implemented in clinical trials. In addition to DIC, thrombocytopenia may be caused by a number of other clinical conditions important to the pediatric critical care provider. The clinical and prognostic significance of thrombocytopenia will be addressed and a focused differential diagnosis will be provided. Thrombotic disorders are becoming increasingly recognized in children and are a particular concern for the pediatric intensivist. The epidemiology of thromboembolism in children will be reviewed focusing on the conditions most commonly associated with these thromboses. Finally, a chapter on hematologic issues in the critically ill child would not be complete without a discussion of sickle cell disease. Acute chest syndrome, one of the most frequent complications of sickle cell disease resulting in the need for intensive care services, will be discussed in detail.

Pulmonary embolism as a cause of death in patients with heart disease: an autopsy study

STUDY OBJECTIVE

To establish the prevalence of pulmonary embolism (PE) in autopsy material at a tertiary cardiac referral center and its importance as a cause of death in patients with heart disease (HD).

DESIGN

Case series.

SETTING

National Heart Institute, Mexico City.

PATIENTS

One thousand thirty-two patients who died at our institution from 1985 to 1994 in whom an autopsy study was performed.

MEASUREMENTS AND RESULTS

Of the 1,032 autopsies reviewed, 231 cases (24.4%) of PE were found; 100 of these patients had a diagnosis of massive PE. Massive PE (obstruction of either of the main pulmonary arteries or more than two lobar arteries) was found to be the third cause of death in this HD population. By age-group distribution, the global prevalence of massive events was higher in patients < 10 years old. Clinical suspicion (premortem) was raised in only 18% of the cases.

CONCLUSIONS

PE was a frequent cause of morbidity and mortality in patients with HD who underwent autopsies. The incidence of massive PE was high in children.

Thromboembolic complications in children with cancer

Thrombosis is a significant problem in patients with cancer. The impact of thromboembolism in association with childhood cancer is not clearly defined. Similarly the information of prevention and management of thromboembolic events in children receiving cancer-therapy is limited. This review aims to examine current knowledge regarding the epidemiology, pathophysiology and management of thrombosis in association with cancer in children.

Clinically important venous thromboembolism in pediatric critical care: a Canadian survey

PURPOSE

Pediatric venous thromboembolism (VTE) is becoming an increasingly recognized morbidity associated with critical illness. The objective of this survey is to identify the patient factors and radiological features that pediatric intensivists consider more or less likely to make a venous thrombosis (VTE) clinically important in their patients.

MATERIALS AND METHODS

Our definition of clinically important VTE was a VTE likely to result in short- or long-term morbidity or mortality if left untreated. We asked respondents to rate the likelihood that patient factors and radiological features make a venous thrombosis clinically important using a 5-point scale (1 = much less likely to 5 = much more likely).

RESULTS

The 38 (58.5%) of 65 pediatric intensivists responding rated 4 patient factors as most likely to make a VTE clinically important: clinical suspicion of pulmonary embolism (mean score, 4.8), symptoms (mean, 4.5), detection by physical exam (mean, 4.4), and the presence of an acute or chronic cardiopulmonary comorbidity that might limit a patient's ability to tolerate pulmonary embolism (mean, 4.3). Of the radiological features, the 2 considered most important were VTE involving the vena cava extending into the right atrium (mean, 5) and central veins (mean, 4.5).

CONCLUSIONS

When labeling a VTE as clinically important, pediatric intensivists rely on several specific patient factors and thrombus characteristics.

Use of Vena Cava Filters in Pediatric Trauma Patients: Data from the National Trauma Data Bank

BACKGROUND

Placement of vena cava filters (VCFs) in high-risk adult trauma patients is a well-described intervention for prophylaxis against pulmonary embolism (PE). Few data exist regarding the use of VCFs in pediatric trauma.

METHODS

We performed a cross-sectional study using the National Trauma Data Bank of the American College of Surgeons. Patients 17 years old or younger were included. Data regarding demographics, injuries, hospitalization, survival, and treating institution were analyzed. The prevalence of deep vein thrombosis (DVT), PE, and VCF placement were calculated. Odds ratios (ORs) for predictors of VCF placement were determined using multivariate logistic regression.

RESULTS

There were 116,357 pediatric patients in the National Trauma Data Bank. VCFs were placed in 214 (0.18%) patients. VCF patients had longer mean hospital (23.99 vs. 4.12 days) and intensive care unit stays (13.65 vs. 1.12 days) and more severe injuries (mean Injury Severity Score, 30.89 vs. 9.04) than those without VCFs. Sixty-five patients had DVT, and PE was diagnosed in 28 patients, representing 0.06% and 0.02% of the cohort, respectively. University-associated teaching hospitals placed 72.4% (95% confidence interval, 65.9-78.3%) of VCFs and Level I trauma centers placed 46.3% (95% confidence interval, 39.4-53.2%) of VCFs. In multivariate analysis, significant predictors of VCF use were DVT (OR, 33.13), spinal cord injury (OR, 15.28), probability of survival (OR, 10.52), severe femur fracture (OR, 3.39), increasing age (OR, 1.99), ISS (OR, 1.05), intensive care unit stay (OR, 1.04), and length of stay (OR, 1.02). Higher Glasgow Coma Scale score decreased the likelihood of VCF use (OR, 0.87).

CONCLUSION

Placement of VCFs in pediatric trauma patients is uncommon and is associated with several characteristics of the patient, the injury, and the treating institution. Long-term VCF efficacy in pediatric trauma is not known, and application of VCFs in these patients requires further investigation.

Deep venous thrombosis in pediatric patients with myelomeningocele undergoing urologic reconstruction—do we need to reconsider prophylaxis?

OBJECTIVES

To review a single surgeon's experience with the development of postoperative deep venous thrombosis after urologic reconstruction in the myelomeningocele population. This complication is rarely reported in this population, despite the multiple risk factors. We reviewed the risk factors for the development of deep venous thrombosis and present options for treatment and prevention of this potentially life-threatening complication.

METHODS

We reviewed a single surgeon's population of myelomeningocele patients who had undergone urologic reconstruction during a 7-year period. This series was examined retrospectively for the development of deep venous thrombosis and its evaluation and treatment.

RESULTS

A total of 61 patients with myelomeningocele who had undergone urologic reconstruction during a 7-year period were identified. Of these 61 patients, deep venous thrombosis was diagnosed in 2. The risk factors common in this population were chronic immobility, recent surgery, and infection.

CONCLUSIONS

Deep venous thrombosis is a rarely reported complication after urologic reconstruction in the myelomeningocele population. The preoperative risk factors should be evaluated. Diligent surveillance postoperatively should be maintained. Evaluation and treatment should be prompt to decrease the risk of serious pulmonary complications.

Pulmonary thromboembolism in children

Pulmonary thromboembolism (PTE) is uncommonly diagnosed in the pediatric patient, and indeed often only discovered on autopsy. The incidence of pediatric PTE depends upon the associated underlying disease, diagnostic tests used, and index of suspicion. Multiple risk factors can be found including: peripartum asphyxia, dyspnea, haemoptysis, chest pain, dehydration, septicemia, central venous lines (CVLs), trauma, surgery, ongoing hemolysis, vascular lesions, malignancy, renal disease, foreign bodies or, uncommonly, intracranial venous sinus thrombosis, burns, or nonbacterial thrombotic endocarditis. Other types of embolism can occur uncommonly in childhood and need to be recognized, as the required treatment will vary. These include pulmonary cytolytic thrombi, foreign bodies, tumor and septic emboli, and post-traumatic fat emboli. No single noninvasive test for pulmonary embolism is both sensitive and specific. A combination of diagnostic procedures must be used to identify suspect or confirmed cases of PTE. This article reviews the risk factors, clinical presentation and treatment of pulmonary embolism in children. It also highlights the current diagnostic tools and protocols used to evaluate pulmonary embolism in pediatric patients.

Analysis of pediatric thrombotic patients in Turkey

This study analyzes the data of thrombotic children who were followed up in different pediatric referral centers of Turkey, to obtain more general data on the diagnosis, risk factors, management, and outcome of thrombosis in Turkish children. A simple two-page questionnaire was distributed among contact people from each center to standardize data collection. Thirteen pediatric referral centers responded to the invitation and the total number of cases was 271. All children were diagnosed with thromboembolic disease between January 1995 and October 2001. Median age at time of first thrombotic event was 7.0 years. Of the children 4% of the cases were neonates, 12% were infants less than 1 year old, and 17% were adolescents. Thromboembolic event was mostly located in the cerebral vascular system (32%), deep venous system of the limbs, femoral and iliac veins (24%), portal veins (10%), and intracardiac region (9%). Acquired risk factors were present in 86% of the children. Infection was the most common underlying risk factor. Inherited risk factors were present in 30% of the children. FVL was the most common inherited risk factor. Acquired and inherited risk factors were present simultaneously in 19% of the patients. Eleven children had a history of familial thrombosis. Due to the local treatment preferences, the treatment of the children varied greatly. Outcome of the 142 patients (52%) was reported: 88 (62%) patients had complete resolution, 47 (33%) had complications, 12 (9%) had recurrent thrombosis, and 34 (24%) died. Three children (2.1%) died as a direct consequence of their thromboembolic disease. The significant morbidity and mortality found in this study supports the need for multicentric prospective clinical trials to obtain more generalizable data on management and outcome of thrombosis in Turkish children.

End-stage renal disease from glomerulonephritis associated with anti-phospholipid syndrome

Primary anti-phospholipid syndrome (APS) is perceived to be an uncommon disorder, infrequently recognized as a cause of renal disease in childhood. While renal involvement in APS classically manifests as thrombotic events, other renal diseases associated with APS have been reported in adults, including membranous nephropathy and minimal change disease. We report our experience of caring for a child who presented with acute anuric renal failure due to anti-neutrophilic cytoplasmic antibody-negative rapidly progressive glomerulonephritis (RPGN), with concomitant thrombotic microangiopathy (TMA). Recognition of the APS as a cause of the patient's TMA facilitated institution of anticoagulation. Our patient's renal failure did not improve and the patient remained dependent on dialysis until he was successfully transplanted. The purpose of our report is to make health-care professionals aware of the previously unreported association of pauci-immune RPGN and APS in children; early recognition of APS will allow initiation of anticoagulation to prevent recurrent thromboses and enable successful transplantation.

Clinical manifestations of the prothrombin G20210A mutation in children: a pediatric coagulation consortium study

The prothrombin G20210A mutation is a common risk factor for thrombosis which increases the risk of deep vein thrombosis, stroke, and fetal loss. There are few publications of its clinical manifestations in children. Our objective was to determine the clinical manifestations of the prothrombin mutation in children. Via survey of pediatric hematologists, we collected data on children with thrombosis and the prothrombin mutation. Thirty-eight patients with a thrombotic event were identified as having the prothrombin mutation. Children with arterial thrombosis were younger, less than half had additional risk factors present at the time of the event, and had a high frequency of central nervous system thrombosis. Children with venous thrombosis were older, almost always had additional risk factors present, and had thrombosis occur most often in the extremities, although there were also a significant number of events in the central venous and cerebral circulation. There was a striking predilection for central nervous system events as 30% of all the events and 67% of the arterial events occurred there. In all, 14/38 children (37%) had central nervous system thrombosis. Unlike factor V Leiden and deficiencies of proteins C and S which cause venous thromboembolism, the prothrombin mutation in children is often associated with arterial thrombosis and with central nervous system events. In children with the prothrombin mutation and venous thrombosis, other risk factors are usually present. Therefore, children with arterial or venous thrombosis of any location should be evaluated for the presence of the prothrombin mutation.

Factor VIII levels in children with thrombosis

BACKGROUND

A number of coagulation defects have been implicated as risk factors in thrombo-embolic disease. Of these, high levels of clotting factor VIII have been shown to be associated with a five- to six-fold increased risk of thrombosis, compared to levels < 100 IU/dL in adults. The objective of this study was to investigate the prevalence of elevated plasma levels of factor VIII in a pediatric population with thrombo-embolism (TE).

METHODS

Forty-two children (17 female, 25 male) with TE and 165 healthy controls without familial history of thrombosis or stroke were included in the present study. Doppler ultrasonography with or without angiography, computed tomography, magnetic resonance imaging or echocardiography was utilized to establish the diagnosis. One-stage clotting assay with factor VIII-deficient plasma for measurement of factor VIII and immunoturbidometric assay for von Willebrand factor (vWF) levels were utilized. All measurements were performed in duplicate. Plasma levels of factor VIII were assessed in parents of nine patients to establish whether high levels of factor VIII were genetically determined.

RESULTS

The median age at onset of TE was 7 years (range 0-17 years). Among patients with TE compared to controls, the prevalence of high factor VIII levels was 59.5% versus 12.1% (odds ratio 10.6, 95% CI: 4.9-23.1). The prevalence of high factor VIII levels was detected in at least one of nine families.

CONCLUSION

The data in the present study provide evidence that elevated plasma factor VIII levels are associated with increased risk of thrombosis in children: thus, plasma concentration of factor VIII should be measured in all children with TE.

Thromboembolic diseases of childhood

Over the last decade, pediatric thrombophilia programs have emerged around the world as a new discipline in pediatric hematology. These programs specialize in the diagnosis, prevention and treatment of children with thromboembolic events (TEs) in both the venous and arterial systems. The need for separate pediatric programs has been discussed previously. (J Pediatr Hematol Oncol 1997; 19: 7-22.) The following article will update previous reviews (Hematol Oncol Clin North Am 1998; 12: 1283-1312; Thromb Haemost 1997; 78: 715-725) and will concentrate on three aspects: (1) The risk factors for acquiring TEs; (2) The confirmatory diagnostic tests used in children with TEs; and (3) The different antithrombotic agents used for prevention and treatment. The current knowledge in respect to the above points is only the "tip of the iceberg". Well-designed prospective trials are required to establish the contribution of congenital prothrombotic disorders, appropriate diagnostic strategies, and optimal therapy for children with TEs.

Pediatric thrombosis

Although thrombosis is less frequent in children than in adults, it represents a significant source of morbidity and mortality. Multiple factors. both genetic and acquired. contribute to the development of thrombosis in chiidren. Thrombosis in a child warrants investigation of potential underlying prothrombotic conditions. The risk of thrombosis in children with heterozygous deficiencies is not clearly defined, but it appears that children who are heterozygous for more than one risk factor or who have a combination of inherited and acquired defects are at higher risk for thrombosis. Treatment of thrombosis primarily involves a rapidly acting anticoaguiant such as heparin or LMWH to prevent extension, and long-term anticoagulation with warfarin may be instituted to prevent recurrence. Thrombolytic therapy with recombinant tissue plasminogen activator also appears to be safe and effective in children. Prospective and multicenter studies are still needed to clarify the contribution of specific prothrombotic disorders to childhood TE so that evidence-based treatment recommendations can be made.

Management of preterm infants with intracardiac thrombi: use of thrombolytic agents

Improvement in neonatal care has led to improvements in survival and patient outcome in preterm infants; however, this improved survival has been associated with the development of secondary complications, such as catheter-associated intravascular and intracardiac thrombus formation with a non-negligible morbidity and mortality. The sick preterm infant is at high risk of catheter-related thrombus formation because of the combination of a high prothrombotic activity, low levels of natural anticoagulants, and various imbalances in the fibrinolytic systems. Based on clinical experience in adults and children, and several neonatal case reports demonstrating the efficacy and tolerability of specific thrombolytic treatment, this approach should be recommended as a first choice treatment in the premature infant with intracardiac or intravascular thrombosis. The thrombolytic agents of choice are urokinase or tissue plasminogen activator (tPA); however, none of them have proven to be superior to the other in terms of efficacy or tolerability, either in adult patients or premature infants. In the past, it has been suggested that newborn infants may require higher doses of thrombolytic agents than adults for effective systemic thrombolysis; however, based on more recent in vitro studies, it seems unlikely that this is true. Nevertheless, systemic (high dose) fibrinolysis is of concern as premature neonates present an increased risk of cerebral haemorrhage during the first weeks of life; therefore, low dose treatment has been proposed with, if possible, direct infusion of the fibrinolytic agent into, or close to, the thrombus. This approach has proven to be efficient and well tolerated in several small case series of newborn and preterm infants. Recommended doses are 1000 to 3000 U/kg/h for urokinase or 0.01 to 0.05 mg/kg/h for tPA. A systemic proteolytic state will not be induced by this low dose; however, specific monitoring of fibrinogen plasma levels has to be recommended. Fibrinogen levels should remain above 100 mg/dL during low dose treatment. Lower levels of fibrinogen will indicate the presence of an unwanted systemic fibrinolytic state. After successful thrombolysis, a follow-up treatment, preferentially with low-molecular-weight heparin for neonates at adjusted doses, should be instituted for at least 6 weeks in the absence of any persisting thrombophilic factor. A longer course (3 to 6 months) of anticoagulation therapy is recommended when thrombophilic factors (i.e. hereditary thrombophilia or central venous catheter still in place) are present. Furthermore, it is recommended that any neonate with thrombosis should be evaluated for hereditary thrombophilia later in life.

Long-term follow-up of Greenfield inferior vena cava filter placement in children

OBJECTIVE

The long-term results of Greenfield inferior vena cava (IVC) filter placement have been well documented in adults; however, similar data do not exist for pediatric patients. The potential for growth and the increased life expectancy in younger patients may contribute to a difference in the natural history of filters placed in children. The objective of this study was to evaluate the long-term outcome of pediatric patients with IVC filters.

METHODS

At the University of Massachusetts Memorial Medical Center, medical records and radiographs of patients 18 years old or younger at the time of IVC filter placement were reviewed. Follow-up data were obtained by interview, physical examination, and venous duplex ultrasound scanning.

RESULTS

A total of 15 IVC filters were placed in children 18 years old or younger between 1983 and 1999. In 10 patients the indications for IVC filter placement were lower-extremity deep venous thrombosis (DVT) and/or pulmonary embolism. In five patients, prophylactic filters were placed in the absence of DVT because of a high risk for the development of pulmonary embolism. Surgical exposure of the right internal jugular vein was used to place the first eight filters. The remainder were inserted percutaneously through the right internal jugular vein or the right common femoral vein. There were no complications or mortality related to filter insertion. Follow-up of the surviving 14 patients ranged from 19 months to 16 years. During long-term follow-up, no patient had a pulmonary embolus. Of the nine patients who had lower-extremity DVT, three developed mild common femoral venous reflux documented by duplex scan. Of the five patients who had prophylactic filters, four had no symptoms or duplex evidence of reflux. The other patient, who was paraplegic, had bilateral leg edema but no venous varicosities and no reflux on duplex scan 11 years after filter placement. No patient in either group had chronic venous obstruction.

CONCLUSION

In long-term follow-up there were no instances of pulmonary embolism, IVC thrombosis, significant postphlebitic symptoms, or significant filter migration among 14 pediatric patients with Greenfield IVC filters. This suggests a safety profile and efficacy similar to that seen in adults.

Thrombosis in the intensive care unit: etiology, diagnosis, management, and prevention in adults and children

Venous thromboembolism, a well-recognized complication in postoperative patients, is emerging as a frequent complication in critically ill patients in intensive care units. Diagnosis can be particularly difficult in such patients because underlying systemic illnesses may mask common presenting signs and symptoms. Although numerous independent risk factors have been identified, the critical role of both central venous catheters and prothrombotic disorders as significant risk factors is a common theme in the pediatric and adult literature. Various diagnostic tests exist, with venography remaining the gold standard and newer, less invasive methods such as ultrasonography and impedance plethysmography becoming increasingly popular. Standard unfractionated heparin remains the mainstay of therapy and prophylaxis, although the use of low molecular weight heparins is becoming more commonplace. Thrombolytic therapy continues to be reserved for severe, life-threatening, acute thrombosis. In this article, we review the common risk factors, diagnostic modalities, and treatment options for venous thromboembolism in critically ill adult and pediatric patients.

Outcome of noncatheter-related thrombosis in children: influence of underlying or coexisting factors

PURPOSE

To determine the hereditary and nonhereditary risk factors contributing to the development of noncatheter-related thrombosis in children.

PATIENTS AND METHODS

Ninety-five children with noncatheter-related thrombosis from a single center were analyzed for clinical manifestations and outcome during a period of 3.5 years. Patients with thrombosis were evaluated for congenital and acquired risk factors, and patients were screened for factor V Leiden, prothrombin 20210A mutations, protein C, protein S, antithrombin III deficiencies, and antiphospholipid antibodies.

RESULTS

Twelve patients (12.5%) died of thrombosis that was associated with a nonmalignant underlying disorder, and 19 patients (20%) had significant complications, including amputation of extremities, epilepsy, hemiplegia, portal hypertension, recurrence of deep vein thrombosis, and postphlebitic syndrome. Two common mutations (factor V Leiden and prothrombin 20210A) were found in 32.5% of the patients with thrombosis. The most frequent underlying disorder was infection (68%). Ninety-three patients (98%) had one or more risk factors.

CONCLUSIONS

The coexistence of an underlying disorder and the presence of predisposing factors such as infection and the factor V Leiden mutation may cause high rates of death and complications in children with noncatheter-related thrombosis. The results of this study indicate that the underlying disorder and the site of thrombosis determine the rates of death and complications in children with thrombosis.

Evaluation and treatment of thrombosis in the neonatal intensive care unit

Thromboses are infrequent but serious complications of patients in the NICU. Thromboses tend to occur in very sick neonates, particularly preterm neonates, and the majority of such thromboses are related to central vascular catheters. Other risk factors for neonatal thromboses include infants of diabetic mothers, sepsis, small for gestational age, congenital heart disease, maternal antiphospholipid syndrome, and possibly inherited prothrombotic disorders. Appropriate treatment, dosage, and duration of therapy for neonatal thromboses has not been studied in clinical trials. Treatment options include observation, anticoagulation, thrombolysis, and surgical thrombectomy. Regardless of the treatment chosen, all neonates with thromboses require frequent reassessment of the thromboses by angiography, echocardiography, or ultrasound until thrombus resolution occurs.