Prevalence of deep venous thrombosis in the lower extremities of children in the intensive care unit

Virchow's triad in "silent" deep vein thrombosis

OBJECTIVE

While determining the incidence of chronic deep vein thrombosis (DVT) and the hypercoagulation profiles of patients who underwent venous stenting for symptomatic venous insufficiency, we assessed the significance of Virchow's triad in the setting of proximal venous outflow obstruction and DVT.

METHODS

Within our registry of 500 patients who underwent venous stenting for proximal venous outflow obstruction between 2013 and 2016, we selected the first 152 consecutive patients who had routine hypercoagulation profile testing performed preoperatively. Statistical analysis was performed using independent t-tests, χ² tests, and multiple logistic regressions.

RESULTS

By history or intraoperative chronic postphlebitic changes (CPPCs), 77 patients (50.7%) were positive for remote DVT; 51 (33.6%) had intraoperative findings of CPPCs without a history of DVT, 20 (13.2%) had intraoperative CPPCs with a history of DVT, and 6 (3.9%) had a history of DVT without intraoperative findings. The χ² tests were significant for increased findings of CPPCs among patients with a history of DVT (81% vs 38%; P < .01). The χ² tests were also significant for increased rates of intraoperative findings of CPPCs in patients with one or more positive hypercoagulation markers (67% vs 42%; P < .01). The most significant predictor for findings of CPPCs or DVT history was the presence of at least one hypercoagulation marker (n = 148; odds ratio, 2.41; P = .022).

CONCLUSIONS

Remote history of DVT and intraoperative findings of CPPCs were prevalent. CPPC findings were found in many patients with no history of DVT. Hypercoagulation markers conferred significant predictive value for DVT. This information may influence our understanding of Virchow's triad and DVT etiology.

Venous thromboembolism following inpatient pediatric surgery: Analysis of 153,220 patients

PURPOSE

To evaluate venous thromboembolism (VTE) rates and risk factors following inpatient pediatric surgery.

METHODS

153,220 inpatient pediatric surgical patients were selected from the 2012-2015 NSQIP-P database. Demographic and perioperative variables were documented. Primary outcome was VTE requiring treatment within 30 postoperative days. Secondary outcomes included length of stay (LOS) and 30-day mortality. Prediction models were generated using logistic regression. Mortality and time to VTE were assessed using Kaplan-Meier survival analysis.

RESULTS

305 patients (0.20%) developed 296 venous thromboses and 12 pulmonary emboli (3 cooccurrences). Median time to VTE was 9 days. Most VTEs (81%) occurred predischarge. Subspecialties with highest VTE rates were cardiothoracic (0.72%) and general surgery (0.28%). No differences were seen for elective vs. urgent/emergent procedures (p = 0.106). All-cause mortality VTE patients was 1.2% vs. 0.2% in patients without VTE (p < 0.001). After stratifying by American Society of Anesthesiologists (ASA) class, no mortality differences remained when ASA < 3. Preoperative, postoperative, and total LOSs were longer for patients with VTE (p < 0.001 for each). ASA ≥ 3, preoperative sepsis, ventilator dependence, enteral/parenteral feeding, steroid use, preoperative blood transfusion, gastrointestinal disease, hematologic disorders, operative time, and age were independent predictors (C-statistic = 0.83).

CONCLUSIONS

Pediatric postsurgical patients have unique risk factors for developing VTE.

LEVEL OF EVIDENCE

Level II.

Central venous catheter-related thrombosis and thromboprophylaxis in children: a systematic review and meta-analysis

OBJECTIVES

In preparation for a pediatric randomized controlled trial on thromboprophylaxis, we determined the frequency of catheter-related thrombosis in children. We also systematically reviewed the pediatric trials on thromboprophylaxis to evaluate its efficacy and to identify possible pitfalls in the conduct of these trials.

PATIENTS/METHODS

We searched MEDLINE, EMBASE, Web of Science and the Cochrane Central Register for Controlled Trials for articles published until December 2013. We included cohort studies and trials on patients aged 0-18 years with central venous catheters who underwent active surveillance for thrombosis with radiologic imaging. We estimated the pooled frequency of thrombosis and the pooled risk ratio (RR) with thromboprophylaxis by using a random effects model.

RESULTS

From 2651 articles identified, we analyzed 37 articles with 3128 patients. The pooled frequency of thrombosis was 0.20 (95% confidence interval [CI] 0.16-0.24). In 10 trials, we did not find evidence that heparin-bonded catheters (RR 0.34; 95%CI 0.01-7.68), unfractionated heparin (RR 0.93; 95% CI 0.57-1.51), low molecular weight heparin (RR 1.13; 95% CI 0.51-2.50), warfarin (RR 0.85; 95%CI 0.34-2.17), antithrombin concentrate (RR 0.76; 95% CI 0.38-1.55) or nitroglycerin (RR 1.53; 95%CI 0.57-4.10) reduced the risk of thrombosis. Most of the trials were either not powered for thrombosis or were powered to detect large, probably unachievable, reductions in thrombosis. Missing data on thrombosis also limited these trials.

CONCLUSIONS

Catheter-related thrombosis is common in children. An adequately powered multicenter trial that can detect a modest, clinically significant reduction in thrombosis is critically needed. Missing outcome data should be minimized in this trial.

Venous thromboembolism in children: preliminary results of a survey of POSNA members

BACKGROUND

The term venous thromboembolism (VTE) includes deep venous thrombosis of the extremity and pulmonary embolism, a potentially fatal clinical entity. Although the prevalence of VTE may be lower in children compared with adults, recent reports suggest a possible rise in this diagnosis among pediatric patients, especially in association with certain risk factors. We assessed the clinical experience and practice of members of the Pediatric Orthopaedic Society of North America (POSNA) related to VTE among their pediatric patients.

METHODS

A 36-question online survey was sent to all 636 active POSNA members. The proportion of surgeons who had encountered at least 1 child with VTE and the respondents' practice of using thromboprophylaxis in children (<18 y old) was assessed. The relationship of responders' experience with VTE among pediatric patients with various practice characteristics was evaluated.

RESULTS

The response rate was 56% (354/636). More than half (55%) [95% confidence interval (CI), 50%-60%] of the respondents could recall at least 1 (median, 2 cases/member) pediatric patient with deep venous thrombosis and 29% (95% CI, 24%-34%) could recall ≥1 child with pulmonary embolism. Approximately one quarter (23%) (95% CI, 18%-27%) of all respondents reported never using mechanical prophylaxis and almost one half (45%) (95% CI, 40%-50%) of respondents reported never using pharmacologic prophylaxis against VTE in children. Only 16% (95% CI, 12%-20%) of the respondents had a thromboprophylaxis protocol for pediatric patients. Respondent characteristics such as being in clinical practice <5 years (P=0.01) and having a surgical volume of <100 cases/y (P=0.03) were associated with a lower likelihood of encountering a pediatric patient with VTE.

CONCLUSIONS

More than half of responding active POSNA members reported having come across at least 1 case of VTE among pediatric patients during their practice. The routine use of VTE prophylaxis for children is uncommon among pediatric orthopaedists. Further studies aimed at determining the prevalence of VTE and developing specific guidelines for prophylaxis among pediatric patients seeking orthopaedic care are warranted.

LEVEL OF EVIDENCE

IV.

Musculoskeletal ultrasonography of the lower extremities in infants and children

Ultrasonography is a powerful diagnostic imaging tool for evaluating lower extremity anatomy and pathology in children. Indications for pediatric musculoskeletal lower extremity sonography include developmental dysplasia of the hip, hip joint sonography for the child with a painful hip, evaluation and characterization of superficial soft-tissue masses, evaluation for deep venous thrombosis, and foreign body localization, characterization and removal. This review highlights these established indications, but primarily focuses on additional US applications for evaluation of the lower extremities, including diagnosis and characterization of arthritis and monitoring of therapy, evaluation of tendon tears and muscle strain injuries, characterization of soft-tissue masses and evaluation of certain congenital abnormalities of the lower extremities. Techniques for optimal utilization of musculoskeletal US in children are also discussed.

Thrombosis risk factor assessment and implications for prevention in critically ill children

OBJECTIVES

To describe nursing compliance with a computer-based pediatric thrombosis risk assessment tool; to generate an estimate of risk factors present in our population; and to explore relationships between risk factors and confirmed thrombotic events.

DESIGN

Institutional review board-approved prospective, observational cohort study.

SETTING

Pediatric intensive care unit within a tertiary care children's hospital.

PATIENTS

All infants and children admitted to the pediatric intensive care unit during a 6-month study period (January 1, 2010-June 30, 2010).

MEASUREMENTS AND MAIN RESULTS

Eight hundred admissions were enrolled, representing 742 patients. Thrombosis risk assessment scores were recorded for 707 admissions (88% of total). Mean age = 6.95 ± 6 yrs, mean weight = 28 ± 23 kg, 45% female. A total of 32 thrombi (14 prehospital and 18 in-hospital) were present in the study group. This translated to an overall occurrence rate of 4.3% (1.9% for prehospital and 2.4% for in-hospital). Logistic regression identified that for every 1-point increase in total thrombosis score, the risk of developing a symptomatic thrombus increased by 1.57-fold (95% confidence interval 0.192-5.5) to 2.12-fold (95% confidence interval 0.175-18.34), for prehospital and in-hospital thrombi, respectively (p < .05). The most important risk factors identified for development of any thrombus were thrombophilia (acquired or inherited) (p < .001), presence of a central catheter (p = .01), and age <1 or >14 yrs (p = .052).

CONCLUSIONS

Incorporation of a scoring system into the bedside nursing assessment flow sheet was successful and identified children at risk for in-hospital thrombosis. The overall score appears to be most indicative of thrombus risk. These data may serve as a platform for future development of routine screening and possible interventional trials in critically ill children.

Characterization of central venous catheter-associated deep venous thrombosis in infants

PURPOSE

Deep venous thrombosis (DVT) is a frequent complication in infants with central venous catheters (CVCs). We performed this study to identify risk factors and risk-reduction strategies of CVC-associated DVT in infants.

METHODS

Infants younger than 1 year who had a CVC placed at our center from 2005 to 2009 were reviewed. Patients with ultrasonically diagnosed DVT were compared to those without radiographic evidence.

RESULTS

Of 333 patients, 47% (155/333) had femoral, 33% (111/333) had jugular, and 19% (64/333) had subclavian CVCs. Deep venous thromboses occurred in 18% (60/333) of patients. Sixty percent (36/60) of DVTs were in femoral veins. Femoral CVCs were associated with greater DVT rates (27%; 42/155) than jugular (11%; 12/111) or subclavian CVCs (9%; 6/64; P < .01). There was a 16% DVT rate in those with saphenofemoral Broviac CVCs vs 83% (20/24) in those with percutaneous femoral lines (P < .01). Multilumen CVCs had higher DVT rates than did single-lumen CVCs (54% vs 6%, P < .01), and mean catheter days before DVT diagnosis was shorter for percutaneous lines than Broviacs (13 ± 17 days vs 30 ± 37 days, P = .02). Patients with +DVT had longer length of stay (86 ± 88 days vs 48 ± 48 days, P < .01) and higher percentage of intensive care unit admission (82% vs 70%, P = .02).

CONCLUSIONS

Deep venous thrombosis reduction strategies in infants with CVCs include avoiding percutaneous femoral and multilumen CVCs, screening percutaneous lines, and early catheter removal.

Thrombosis in the pediatric population

Whereas thrombotic events in critically ill children do not occur as commonly as in adults, they are being recognized with increasing frequency in the pediatric intensive care unit. The reasons for this are not clear but likely include an increased awareness of the problem and the ability to make a diagnosis using relatively noninvasive tests. In this section, I attempt to define the extent of the problem, summarize and discuss the relevant literature (pointing out where published experience in the pediatric population differs from that in adult patients), and suggest some guidelines regarding thrombophilia treatment and the management of thrombotic events.

Inferior vena cava thrombosis causing acute cauda equina syndrome

The authors report a case of a 16-year-old girl who presented with a 1-week history of progressive low-back pain, buttock paresthesias, and bilateral lower extremity pain and weakness. Magnetic resonance (MR) imaging and MR venography studies of her lumbar spine revealed engorgement of the epidural venous plexus and mild compression of the cauda equina. A lower extremity and pelvic venogram revealed occlusive thrombosis of the femoral and iliac veins as well as of the inferior vena cava (IVC). The patient required an IVC thrombectomy due to progressive symptoms, after which she improved and returned to baseline status in 1 week. Imaging studies afterwards showed resolution of the venous engorgement and decompression of the cauda equina. This is the second published report of an association between IVC thrombosis and cauda equina syndrome.

Pulmonary embolism: an unsuspected killer

The presentation of PE is often subtle and may mimic other diseases. Many pulmonary emboli invariably preclude diagnosis by their occult nature or by leading to rapid death from cardiopulmonary arrest. In patients who do manifest symptoms from PE, accurate diagnosis is essential. Often it is difficult to distinguish the vague symptoms of PE from other diagnoses, such as acute coronary syndrome, pneumonia, COPD, CHF,aortic dissection, myocarditis or pericarditis, pneumothorax, and musculo-skeletal or gastrointestinal causes. Regardless of the presentation, the most fundamental step in making the diagnosis of PE is first to consider it. Historical clues and risk factors should raise the clinician's suspicion.PE is an unsuspected killer with a nebulous presentation and high mortality. In all likelihood, PE will remain an elusive diagnosis despite advances in technology and a wealth of research. A high index of suspicion is required, but no amount of suspicion would eliminate all missed cases. Patients with significant underlying cardiopulmonary disease seem to be the most challenging. Patients with significant comorbidity have poor reserve and are likely to have poor outcomes, especially if the diagnosis is not made and anticoagulation is not initiated early. Controversy exists over the best diagnostic approach to PE. A battery of diagnostic studies is available, with few providing definitive answers. Studies such as CT may be helpful at some institutions but offer poor predictive value at others. Other diagnostic tests are not universally available. It is hoped that further research and improvements in current diagnostic modalities will clear some of the current confusion and controversy of this ubiquitous and deadly disease.

Clinical review: vascular access for fluid infusion in children

The current literature on venous access in infants and children for acute intravascular access in the routine situation and in emergency or intensive care settings is reviewed. The various techniques for facilitating venous cannulation, such as application of local warmth, transillumination techniques and epidermal nitroglycerine, are described. Preferred sites for central venous access in infants and children are the external and internal jugular veins, the subclavian and axillary veins, and the femoral vein. The femoral venous cannulation appears to be the most safe and reliable technique in children of all ages, with a high success and low complication rates. Evidence from the reviewed literature strongly supports the use of real-time ultrasound techniques for venous cannulation in infants and children. Additionally, in emergency situations the intraosseous access has almost completly replaced saphenous cutdown procedures in children and has decreased the need for immediate central venous access.

Risk factors for venous thromboembolism in pediatric trauma

BACKGROUND

Venous thromboembolism (VTE) is a major source of morbidity in critically ill trauma patients. Although the incidence and risk factors for VTE after trauma in adults have been well described, similar data regarding pediatric patients are lacking.

METHODS

Pediatric (age < 16 years) trauma patients with VTE were identified from a large administrative database collated from 19 states across the United States. Risk factors for VTE were identified using multivariate techniques.

RESULTS

Risk of VTE increased with age and Injury Severity Scores. VTE was clearly associated with head, thoracic, abdominal, lower extremity, and spinal injuries. Craniotomy, laparotomy, and spinal operations were also associated with VTE. The greatest risk of VTE was in children with venous catheters.

CONCLUSION

Older children with high Injury Severity Scores, major vascular injury, craniotomy, or venous catheters are at risk for VTE. These data may help guide strategies geared toward screening and prophylaxis in injured children.

A procedure for placing pediatric femoral venous catheter tips near the right atrium

OBJECTIVE

To find a body measurement that would serve as an index for determining the length of femoral venous catheter to be inserted to achieve a position near the right atrium.

METHODS

A candidate index measurement was chosen, and radiographic measurements of routine femoral venous catheter placements were compared with the placement that may have resulted from use of the index in a group of patients. In a subsequent group, the candidate index was used to choose catheter insertion length, the accuracy of which was again evaluated from routine placement radiographs.

RESULTS

The first series of radiographic measurements predicted that use of the sternal-umbilical-puncture (SUP) index would result in acceptable and accurate catheter tip placement. This was confirmed in the second group of patients in which 11 of 12 catheter tips were within 1 cm of the target position.

CONCLUSIONS

The use of the SUP index ensures acceptable accuracy in estimating the required insertion length of femoral catheter when tip placement near the right atrium is the clinical goal.

Special situations: pediatric, pregnant, and geriatric patients

Venous thromboembolic disease is not an uncommon problem associated with the geriatric patient. These patients are at significantly increased risk of DVT and PE compared with their younger counterparts. Their associated morbidity and mortality is also higher. Treatment of thrombotic disease in these patients necessitates close monitoring owing to their enhanced sensitivity to the effects of anticoagulants.

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.

Venous thromboembolic disease in the pediatric intensive care unit

Long recognized to be a major source of morbidity in the adult population, venous thromboembolism is being increasingly recognized in the pediatric age group. Pediatric intensive care unit patients are exposed to multiple risk factors for venous thromboembolism. Prothrombotic tendencies may be inherited or acquired, secondary to either the underlying disease or selected therapeutic interventions. In children in whom venous thromboembolism is diagnosed, the most commonly identified risk factor is the presence of a central venous catheter. Many cases are not diagnosed until autopsy. Because current treatment recommendations are extrapolated from adult studies, further investigation is needed to define the optimal treatment and prophylaxis regimens in critically ill children.

Superficial venous thrombosis presenting as a painful popliteal fossa mass in a child

We report an unusual case of superficial venous thrombosis in a cyanotic 12-year-old child who had undergone recent appendectomy. Although compression, color Doppler, and duplex ultrasound techniques remain the keys to the diagnosis of venous thrombosis, SieScape sonography was beneficial in demonstrating the extent of the thrombi and their location along a superficial thrombosed vein.