Prophylaxis for Pediatric Venous Thromboembolism

Current Status and Changes Across Pediatric Orthopaedic Society of North America From 2011

Robert F. Murphy, MD; David Williams, PhD; Grant D. Hogue, MD; David D. Spence, MD; Howard Epps, MD; Henry G. Chambers, MD; Benjamin J. Shore, MD

Disclosures

J Am Acad Orthop Surg. 2020;28(9):388-394. 

In This Article

Discussion

In children, VTE is a relatively rare event for which there is a paucity of literature available. Most guidelines in pediatrics because it pertains to VTE have been extrapolated from adults[15] with essentially no further validation.[16] Although the reported incidence of VTE in children is increasing, the occurrence in pediatric orthopaedic patients appears to be low (0.0515% to 0.68%).[6–9]

Despite this low prevalence, VTE prophylaxis is important to pediatric orthopaedic surgeons because pediatric orthopaedic VTE is associated with significant morbidity and mortality. Guzman et al[7] analyzed the 2012 Kids Inpatient Database and found an overall mortality rate of 0.53% which increased to 0.9% for children with a fracture and further to 1.8% in children with concomitant diagnoses of VTE and a fracture. Baker et al,[9] in a review of complications and 30-day outcomes associated with VTE in pediatric orthopaedic surgical patients, found that the postoperative occurrence of VTE was associated with increased length of stay, pneumonia, unplanned reintubation, urinary tract infection, and line-associated bloodstream infection.

Identifying which patients are at the highest risk for VTE is important so that accurate and effective prophylaxis measures can be implemented. In the pediatric literature, multiple risk factors have been identified for the development of VTE, including increasing age, sex, comorbid conditions, family history, use of oral contraceptives, and obesity.[10,11,17] Specifically in pediatric orthopaedic patients, reported risk factors include fractures, obesity, infection, increasing age, and presence of a central venous catheter.[7–9] This is reflected in the responses on the survey, which listed oral contraceptive use, positive family history, and obesity as the three most common risk factors that guide clinician decision-making in initiating VTE prophylaxis. Table 2 (Supplemental Digital Content 3, http://links.lww.com/JAAOS/A452) lists salient risk factors for VTE for the practicing pediatric orthopaedic surgeon and denotes the top three survey responses correlated with known risk factors.

The occurrence of a VTE in a hospitalized patient has been described a "never event" by the Centers for Medicare and Medicaid Services, with payment implications when a VTE occurs.[18] This has resulted in sweeping measures to introduce and enforce VTE prophylaxis in all patients, including children. However, not all patients are equally at risk for VTE and in children, most VTE is the result of line-associated catheters, critical care patients, and cancer. In children, chemical anticoagulation has been reported to be associated with bleeding complications and should be considered carefully in low-risk patients.[19,20]

Only one-third of the respondents were aware of a specific VTE prophylaxis protocol at their institution, and only 20% were aware of a particular age at which their institutional mandates VTE prophylaxis protocol for all patients. In comparison to the Sabharwal article, despite increasing awareness regarding VTE prophylaxis on a national level, there has been minimal change in practice of POSNA members. Although VTE prophylaxis guidelines have been proposed for adult orthopaedic patients[15] and endorsed for hip and knee arthroplasty[21] and spine surgery,[22] currently there are no nationally recognized guidelines for VTE prophylaxis specifically for pediatric orthopaedic patients. This practice variation has the potential to put our pediatric patients at risk for adverse events regarding pediatric orthopaedic-related VTE.

In an effort to identify children who may be most at risk for the development of a VTE during hospitalization, several groups have proposed pediatric VTE risk assessment and prophylaxis guidelines. The Association of Paediatric Anaesthetists of Great Britain and Ireland Guidelines Working Group on Thromboprophylaxis in Children recently published a comprehensive guideline based on the available literature for VTE prophylaxis in children.[11] These guidelines place emphasis on patient age >13 years and length of time of immobility >48 hours, and then uses the balance of risk factors and bleeding risk to assess the need for the addition of chemical prophylaxis in addition to mechanical prophylaxis. Meier et al[10] in 2014 published "best evidence statement (BESt)" guidelines for VTE prophylaxis in children. In a similar fashion, these authors weighted age >10 years and altered mobility >48 hours as the starting point for consideration of VTE prophylaxis. A follow-up study instituting a quality initiative to screen 603 general surgery and 506 orthopaedic postoperative patients for VTE risk assessment was also completed.[23] After 8 months, the median weekly percentage of the screened orthopaedic patients increased from zero to 46%. Most patients were found to be at low or moderate risk for VTE, and no patients developed a VTE event during the study period. The authors acknowledged that increased screening occurred by refining the screening tool, educating providers, and implementing risk assessment into regular workflow. Figure 2 demonstrates the screening and prophylaxis tool produced by the BESt guidelines. Currently, no specific guidelines exist for pediatric orthopaedic trauma or elective patients, and only 40% respondents in our survey were aware of the BESt guidelines published in 2014.

Figure 2.

Figure illustrating the Best evidence statement guidelines from 2014 for VTE risk assessment and prophylaxis in hospitalized children. GCS = graduated compression stockings, SCD = sequential compression device, VTE = venous thromboembolism

There is limited literature on the rates of VTE for specific pediatric orthopaedic operations. Several authors have used large national databases to report on the prevalence of and risk factors associated with elective pediatric orthopaedic patients,[8] all postoperative pediatric orthopaedic patients,[9] pediatric orthopaedic trauma patients,[6,7] and patients with postoperative spinal fusion.[24] Other reports exist on VTE events in patients with adolescent knee arthroscopy,[25,26] and hip preservation patients.[27] Respondent rates of any VTE prophylaxis based on type of surgery were similar for spine, reconstructive hip, and pelvis/lower extremity trauma surgery (60% to 65%). The lowest rate of prophylaxis was in the neuromuscular cohort (34%). This is not surprising because the literature on this particular morbidity in this patient cohort is exceptionally rare, with only one article by Setty et al[28] identifying neuromuscular disease as one chronic illness associated with VTE in hospitalized children. Rates of chemical prophylaxis were lowest in patients with spine surgery, likely because of concerns epidural hematoma and neurologic dysfunction.[29]

The secondary aim of this survey was to compare current practice patterns with those reported in a similar 2011 survey by Sabharwal and Passannante.[13] Several questions were phrased in a similar fashion to ascertain whether any practice patterns have changed among POSNA members. Owing to a lower response rate compared with the previous survey, a smaller number of respondents reported experiencing either a DVT or PE during their career. The actual number of practitioners who are aware and practicing prophylaxis increased by 20 respondents between the two studies. We hypothesized that awareness regarding VTE prophylaxis for pediatric patients would have increased significantly over the past seven years. We proposed that although the numbers are statistically significant, the change between 55 and 75 surgeons within the POSNA community does not represent a clinically significant change. The results of this survey indicate that despite the low prevalence of VTE in pediatric orthopaedics, the pressure to prophylaxis against VTE continues to grow. It is the authors' opinion and anecdotal experience that pressure to prophylaxis pediatric patients is primarily driven by hospital policies and administrative efforts to attempt to reduce pediatric VTE to a "never event," irrespective of age or other risk factors. Ultimately, this practice and goal is unattainable and may be leading to unnecessary prophylactic measures and costs.

In 2011, the preferred chemical agent used for prophylaxis was enoxaparin,[10] whereas in 2018, the most frequently listed chemical agent was aspirin, which mirrors the changes seen in the adult literature. In 2011, 80% of the respondents listed that chemical VTE prophylaxis was discontinued once the patient was mobilizing independently.[10] In 2018, respondents listed that chemical prophylaxis was discontinued either once the patient was mobilizing independently (40%) or according to a predetermined time (41%).

Limitations of this article include the inherent recall and selection bias associated with the survey type methodology. This may especially be true in the case of VTE, which is a rare and potentially catastrophic event. This may have overestimated the "real" rates of this condition. Second, the response rate in this article was 18%, which was lower than the response rate of 56% of the original survey of POSNA members, but this reflects the trend within POSNA of increasing the frequency of surveys and decreasing member participation. Despite these limitations, we believe that important conclusions can be drawn regarding this study and more information regarding pediatric orthopaedic-related VTE needs to be disseminated to the members of POSNA and orthopaedic providers who care for children.

In conclusion, only a small portion of pediatric orthopaedic surgeons are familiar with their institution VTE prophylaxis protocol and this number has not changed substantively over the past 7 years. Respondent produced risk factors for the initiation of prophylaxis seem to reflect those published in the literature. The length of time used for mechanical and chemical prophylaxis is similar. Understanding the at-risk patients with VTE in pediatric orthopaedics and prophylaxing appropriately will ultimately improve the care we deliver to our patients. Moving forward by standardizing the prophylaxis guidelines for children undergoing orthopaedic procedures, we can improve the quality of care to our patients. This can be accomplished by the development of common VTE pediatric prophylaxis practice guidelines, generated according to the available evidence regarding VTE risk exclusively in pediatric orthoapedic patients.

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