Epidemiology of Lower Extremity Deep Venous Thrombosis in Critically Ill Adolescents

Hospital-Acquired Venous Thromboembolism and Invasive Mechanical Ventilation: A Report From the Children's Hospital Acquired Thrombosis Consortium

OBJECTIVES

To determine if the duration of invasive mechanical ventilation (IMV) was associated with hospital-acquired venous thromboembolism (HA-VTE) among critically ill children.

DESIGN

A multicenter, matched case-control study as a secondary analysis of Children's Hospital Acquired Thrombosis (CHAT) Consortium registry.

SETTING

PICUs within U.S. CHAT Consortium participating centers.

PATIENTS

Children younger than 21 years old admitted to a PICU receiving IMV for greater than or equal to 1 day duration from January 2012 to March 2022 were included for study. Cases with HA-VTE were matched 1:2 to controls without HA-VTE by patient age groups: younger than 1, 1-12, and older than 12 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was IMV duration in days. Descriptive data included demographics, anthropometrics, HA-VTE characteristics (i.e., type, location, and timing), central venous catheterization data, thromboprophylaxis practices, and Braden Q mobility scores. Descriptive, comparative, and associative (multivariate conditional logistic regression for HA-VTE) statistics were employed. A total of 152 cases were matched to 304 controls. Cases with HA-VTE were diagnosed at a median of 7 days (interquartile range [IQR], 3-16 d) after IMV. The HA-VTE were limb deep venous thromboses in 130 of 152 (85.5%) and frequently central venous catheterization-related (111/152, 73%). Cases with HA-VTE experienced a longer length of stay (median, 34 d [IQR, 18-62 d] vs. 11.5 d [IQR, 6-21 d]; p < 0.001) and IMV duration (median, 7 d [IQR, 4-15 d] vs. 4 d [IQR, 1-7 d]; p < 0.001) as compared with controls. In a multivariate logistic model, greater IMV duration (adjusted odds ratio, 1.09; 95% CI, 1.01-1.17; p = 0.023) was independently associated with HA-VTE.

CONCLUSIONS

Among critically ill children undergoing IMV, HA-VTE was associated with greater IMV duration. If prospectively validated, IMV duration should be included as part of prothrombotic risk stratification and future pediatric thromboprophylaxis trials.

Hospital-acquired venous thromboembolism during invasive mechanical ventilation in children: a single-center, retrospective cohort study

BACKGROUND

Invasive mechanical ventilation (IMV) has been independently associated with hospital-acquired venous thromboembolism (HA-VTE) among critically ill children, including extremity deep venous thrombosis and pulmonary embolism.

OBJECTIVES

We aimed to characterize the frequency and timing of HA-VTE following IMV exposure.

METHODS

This was a single-center, retrospective cohort study including children aged <18 years, hospitalized in a pediatric intensive care unit, undergoing mechanical ventilation for >24 hours from October 2020 through April 2022. Encounters with an existing tracheostomy or receiving treatment for HA-VTE prior to endotracheal intubation were excluded. The primary outcomes characterized clinically-relevant HA-VTE, including timing after intubation, location, and the presence of known hypercoagulability risk factors. Secondary outcomes were IMV exposure magnitude, defined by IMV duration and ventilator parameters (ie, volumetric, barometric, and oxygenation indices).

RESULTS

Of 170 consecutive, eligible encounters, 18 (10.6%) experienced HA-VTE at a median of 4 days (IQR, 1.4-6.4) following endotracheal intubation. Those with HA-VTE had an increased frequency of a prior venous thromboembolism (27.8% vs 8.6%, P = .027). No differences in frequency of other HA-VTE risk factors (ie, acute immobility, hematologic malignancy, sepsis, and COVID-19-related illness), presence of a concurrent central venous catheter, or the magnitude of IMV exposure were noted.

CONCLUSION

Children undergoing IMV experience HA-VTE at markedly higher rates than previously estimated in the general pediatric intensive care unit population after endotracheal intubation. While prospective validation is needed, these findings are an important step toward informing the development of risk-stratified thromboprophylaxis trials in critically ill children.

Mechanical Ventilation and Hospital-Acquired Venous Thromboembolism Among Critically Ill Children

OBJECTIVES

To estimate the occurrence of, and evaluate associations between, hospital-acquired venous thromboembolism (HA-VTE) and invasive mechanical ventilation (MV) among children hospitalized in the PICU.

METHODS

We performed a multicenter, retrospective cohort study comparing HA-VTE frequencies among subjects <18 years of age hospitalized in the PICU from January 2018 through December 2019 among 47 participating centers, via the Pediatric Health Information Systems registry. We excluded perinatal encounters, those with VTE present at admission, and those with observational status. The primary outcome was the proportion of HA-VTE events before hospital discharge, including extremity deep venous thrombosis, pulmonary embolism, and organ-specific deep venous thrombosis. The HA-VTE frequencies were compared using χ2 tests. The association between HA-VTE and MV was investigated via multivariable logistic regression, adjusting for previously described VTE risk factors.

RESULTS

Of the 205 231 PICU encounters identified for study, 70 829 (34.5%) underwent MV. The occurrence of HA-VTE was 2.2% and was greater among children who received, versus did not receive, MV (4.4% versus 1.1%, P < .001). Multivariable logistic regression revealed significant association between MV and HA-VTE (odds ratio 2.51, 95% confidence interval 2.33-2.69; P < .001).

CONCLUSIONS

In this multicenter, retrospective, registry-based cohort study, HA-VTE were diagnosed in 2.2% of critically-ill children, and after adjustment for central venous catheterization, MV independently increased the risk of HA-VTE 2.5-fold. These findings warrant prospective validation to inform the design of future risk-stratified clinical trials of thromboprophylaxis in critically-ill children.

Effects of CDT on Hemodynamics and Quality of Life in a Subgroup of Patients with Lower Limb Deep Vein Thrombosis Carel: A Case-Control Study

Objective. To explore the effects of combined catheter-directed thrombolysis (CDT) on hemodynamics and quality of life in a subgroup of patients with lower limb deep vein thrombosis carel by using a case-control study. Methods. Eighty-four patients with deep venous thrombosis (DVT: acute DVT and chronic DVT) of lower extremities treated in our hospital from April 2017 to June 2021 were randomly assigned into the control group ( $n=42$ ) and the research group ( $n=42$ ). The control group only received routine nursing combined with CDT; the research group was treated with cluster nursing l combined with CDT. The clinical efficacy, the difference in limb circumference, hemorheology, hemodynamics, coagulation index and life quality before and after treatment, and the nursing satisfaction scores were calculated. The effects of cluster nursing l combined with CDT on hemodynamics and life quality in patients with DVT of lower extremities were analyzed. Results. The clinical curative effect of the research group was better than that of the control group ( $P<0.05$ ). After intervention, the difference in the thigh and leg perimeter in the research group was reduced, and the difference in the thigh and leg perimeter in the research group was significantly lower than that in the control group ( $P<0.05$ ). After intervention, the whole blood low shear viscosity, plasma viscosity, platelet aggregation rate, and fibrinogen in the research group were lower than those in the control group ( $P<0.05$ ). After intervention, segmental venous volume (SVC), maximum venous blood flow (MVO), and SVC/MVO in the research group were significantly higher than those before intervention, VRT was significantly prolonged, and MVO and venous pressure recovery time (VRT) were significantly higher than those in the control group. After intervention, D-dimer and fibrinogen decreased, prothrombin time and activated partial thromboplastin time increased in the research group, and the improvement of blood coagulation index in the research group was significantly better than that in the control group ( $P<0.05$ ). After intervention, the scores of quality of life in the research group decreased, and the scores of physiological function, psychological function, social function, and health self-cognition in the research group were lower than those in the control group ( $P<0.05$ ). The satisfaction of patients in the research group was significantly higher than that in the control group ( $P<0.05$ ). Conclusion. The application of cluster nursing l combined with CDT can effectively prevent lower limb venous thrombosis after operation and can enhance patients’ hemorheology, hemodynamics, and blood coagulation function and significantly promote their life quality, nursing satisfaction is high, and it is worth popularizing and applying in clinic.

Incidence of Deep Vein Thrombosis in Cerebral Palsy Following an Orthopaedic Surgical Event

PURPOSE

The purpose of this study was to identify the incidence of venous thromboembolism (VTE) and characterize the demographics, comorbidities, and risk factors for patients with cerebral palsy (CP) having orthopaedic surgery.

METHODS

All patients diagnosed with CP who underwent an orthopaedic surgical procedure at one institution between 2008 and 2017 were identified. Diagnosis codes and associated patient events were recovered from the electronic medical record. Each VTE event was reviewed to ascertain an actual VTE episode related to a surgical event.

RESULTS

The review included 2583 orthopaedic surgical events in 1371 patients. Of the initial 88 cases identified, 28 cases had a deep thrombosis documented. Six cases of VTE occurred within 3 months following the surgical event. Three of these cases had thigh thrombosis, and 2 patients had upper arm thrombosis, and 1 patient had a superior vena cava thrombosis. On further workup, 5 of these 6 patients were identified as having a congenital hypercoagulable condition.

CONCLUSIONS

VTE is a relatively rare occurrence after orthopaedic surgery in pediatric patients with CP, but when it occurs, a full hematologic workup for a congenital hypercoagulable condition is indicated. Based on the low incidence of thigh thrombosis, routine pharmacological or intermittent mechanical calf compression is not recommended. A careful clinical and family history should be performed to identify patients with possible genetic hypercoagulable conditions who would merit prophylaxis.

LEVEL OF EVIDENCE

Level IV.

Anti-Xa levels in critically ill children receiving enoxaparin for venothromboembolism prophylaxis

Venothrombolism (VTE) prophylaxis is increasingly utilized in pediatric intensive care units (PICUs). Enoxaparin, a low-molecular weight heparin, is frequently used for this purpose. Enoxaparin can also be used for therapeutic anticoagulation in cases of known thrombus. In such cases, monitoring involves obtaining serum anti- Xa levels with a target value of 0.5-1 units/mL. No monitoring recommendations currently exist for enoxaparin when intended for pediatric VTE prophylaxis. We hypothesize that a clinically important number of patients on VTE prophylaxis with enoxaparin have serum anti-Xa levels consistent with values targeted for therapeutic anticoagulation. We found that over 20% of patients on VTE prophylaxis with enoxaparin had serum anti-Xa levels consistent with true therapeutic anticoagulation (anti-Xa level 0.5-1 units/mL) during their enoxaparin course and 5% achieved values of supratherapeutic anticoagulation (anti-Xa level >1 units/mL). Serum anti-Xa level did not correlate with once versus twice daily dosing, body mass index (BMI), or creatinine level. Blood urea nitrogen (BUN) was found to have a positive odds ratio for an anti-Xa level ≥ 0.5 units/mL. We believe that this incidence of unintended therapeutic anticoagulation indicates a clinically significant number and therefore routine anti-Xa evaluation while on VTE prophylaxis is warranted within our population.

Risks of venous thrombosis and bleeding in critically ill adolescents after trauma or major surgery

BACKGROUND

The risks of venous thromboembolism (VTE) and bleeding in critically ill adolescents based on interventions received and anatomic site of trauma or major surgery may identify a cohort eligible for enrollment in a trial of pharmacologic prophylaxis.

METHODS

This retrospective cohort study using the Virtual Pediatric Systems database included adolescents admitted to pediatric intensive care units after trauma or major surgery between 2013 and 2017. Mixed effects logistic regression was used to determine the adjusted risks of VTE and bleeding with central venous catheterization (CVC), mechanical ventilation (MV) and anatomic site of trauma or major surgery. The adjusted risks were used to identify the cohort eligible for enrollment.

MEASUREMENTS AND MAIN RESULTS

VTE developed in 212 (0.8%) of 27,647 adolescents. The adjusted risk of VTE was >2% with CVC and 2 or more of MV and trauma or major surgery to the brain or abdomen. Excluding those with bleeds present on admission or at high risk of bleeding, 375 (1.4%) adolescents would be eligible for enrollment.

CONCLUSIONS

VTE is generally uncommon in adolescents after trauma or major surgery. The small proportion of adolescents who are at high risk of VTE and at low risk of bleeding impacts the feasibility of a trial.

LEVEL OF EVIDENCE

Prognostic Study Level II.

Improving compliance of risk assessment and nonpharmacological interventions for deep venous thrombosis prevention in a respiratory ICU: a best practice implementation project

OBJECTIVES

To increase the compliance with deep venous thrombosis (DVT) nonpharmacologic prophylaxis best practice recommendations while ensuring appropriate and structured nonpharmacologic prophylaxis for patients in the respiratory ICU.

BACKGROUND

DVT is a major problem for patients, with those who are critically ill representing a high-risk population for developing the condition. Nonpharmacologic prophylaxis is considered an effective intervention. However, the application of such interventions in practice has not been optimal to date.

METHODS

The current project was conducted in a respiratory ICU of a tertiary hospital. Audit criteria were developed on the basis of an evidence summary developed by the Joanna Briggs Institute, whereby the institute's Practical Application of Clinical Evidence System program to facilitate an audit and feedback cycle was utilized as an implementation framework. Baseline and follow-up audits on nonpharmacological DVT prophylaxis were conducted for 35 patients against five evidence-based recommendations. In addition, the nurses' knowledge and attitude regarding DVT prophylaxis were investigated both prior to and postimplementation.

RESULTS

In the baseline audit, compliance with the five evidence-based audit criteria was less than 15%. After the implementation of strategies including education, person-centered care, financial and human-resource support, there was a significant improvement in all the audit criteria. In addition, improvements in the nurses' knowledge and attitude regarding DVT prophylaxis were reported. The rate of discharged patients due to a deterioration of their condition decreased from 31.4 to 5.7% in the follow-up cycle. One DVT patient occurred in the baseline data, whereas no new incidences of DVT were found in the follow-up data.

CONCLUSION

The project not only improved nurses' knowledge and attitude regarding DVT prevention, but also remarkably improved the implementation of nonpharmacological DVT prophylaxis. The application of evidence-based nonpharmacological DVT prophylaxis may improve patients' outcomes in the ICU.

Bayesian analysis of the epidemiology of bleeding in critically ill children

PURPOSE

We updated our findings on the epidemiology of clinically relevant bleeding (CRB) in critically ill children. We also determined the concordance of CRB as defined by the International Society of Thrombosis and Haemostasis, i.e., ISTH definition, and characteristics identified by pediatric intensivists in a recent survey, i.e., survey definition.

METHODS

In a prospective cohort study, we included children <18 years old who were admitted to the pediatric intensive care unit for >1 day. We followed them daily for bleeding. Bayesian inference was used as the primary analytic tool to incorporate our prior findings.

RESULTS

Using the ISTH definition, the estimated frequency of CRB was 10.0% (95% credible interval, CrI: 7.6%, 12.8%) from 41 of 405 children who had CRB. The estimated frequency from 4 of 12 adolescents >13 years old who received mechanical ventilation or vasopressor support and had CRB was 32.9% (95% CrI: 12.0%, 58.8%). Using the survey definition, the estimated frequency of CRB for the entire cohort was 10.8% (95% CrI: 8.3%, 13.8%). Concordance between definitions for each bleeding event was 0.40 (95% confidence interval: 0.27, 0.52).

CONCLUSIONS

Our updated findings highlight the high frequency of CRB regardless of definition used for CRB.

Protein biomarkers for incident deep venous thrombosis in critically ill adolescents: An exploratory study

BACKGROUND

There are no tests to identify critically ill children at high risk of deep venous thrombosis (DVT). In this exploratory study, we aimed to identify proteins that are associated with incident DVT in critically ill adolescents.

PROCEDURE

Plasma samples were obtained from critically ill adolescents within 24 hours after initiation of cardiopulmonary support. The adolescents were followed with ultrasound to detect the development of DVT of the lower extremity and clinically for bleeding. Thrombin-antithrombin complex and prothrombin fragment 1+2 were measured using immunosorbent assays, whereas procoagulation and anticoagulation factors were measured using multiplex assays. Plasma samples were also analyzed using SOMAscan, an aptamer-based capture assay. The associations between DVT and the log-transformed level of the proteins were assessed using logistic regression adjusting for the presence of femoral venous catheter and severity of illness. Associations were expressed as odds ratio (OR) for every log-fold increase in level of the protein with 95% confidence interval (CI).

RESULTS

Plasma from 59 critically ill adolescents, of whom 9 developed incident DVT, was analyzed. The median age of the adolescents was 15.1 years (interquartile range, 14.0-16.7 years). Higher levels of thrombin-antithrombin complex (OR: 31.54; 95% CI: 2.09-475.92) and lower levels of factor XIII (OR: 0.03; 95% CI: 0.002-0.44) were associated with DVT. CD36, MIC-1, and EpoR were marginally associated with DVT. Only factor XIII was associated with clinically relevant bleeding (OR: 0.27; 95% CI: 0.08-0.97).

CONCLUSIONS

We identified candidate protein biomarkers for incident DVT. We plan to validate our findings in adequately powered studies.

Modifying ICCA with Trp-Phe-Phe to Enhance in vivo Activity and Form Nano-Medicine

BACKGROUND

1-(4-isopropylphenyl)-β-carboline-3-carboxylic acid (ICCA) was modified by Trp-Phe-Phe to form 1-(4-isopropylphenyl)-β-carboline-3-carbonyl-Trp-Phe-Phe (ICCA-WFF).

PURPOSE

The object of preparing ICCA-WFF was to enhance the in vivo efficacy of ICCA, to explore the possible targeting action, and to visualize the nano-feature.

METHODS

The advantages of ICCA-WFF over ICCA were demonstrated by a series of in vivo assays, such as anti-tumor assay, anti-arterial thrombosis assay, anti-venous thrombosis assay, P-selectin expression assay, and GPIIb/IIIa expression assay. The nano-features of ICCA-WFF were visualized by TEM, SEM and AFM images. The thrombus targeting and tumor-targeting actions were evidenced by FT-MS spectrum analysis.

RESULTS

The minimal effective dose of ICCA-WFF slowing tumor growth and inhibiting thrombosis was 10-fold lower than that of ICCA. ICCA-WFF, but not ICCA, formed nano-particles capable of safe delivery in blood circulation. In vivo ICCA-WFF, but not ICCA, can target thrombus and tumor. In thrombus and tumor, ICCA-WFF released Trp-Phe-Phe and/or ICCA.

CONCLUSION

Modifying ICCA with Trp-Phe-Phe successfully enhanced the anti-tumor activity, improved the anti-thrombotic action, formed nano-particles, targeted tumor tissue and thrombus, and provided an oligopeptide modification strategy for heterocyclic compounds.

Epidemiology of Clinically Relevant Bleeding in Critically Ill Adolescents

OBJECTIVES

The epidemiology of clinically relevant bleeding in critically ill adolescents, particularly those who are at high risk of venous thromboembolism, is unclear. In preparation for a randomized clinical trial of pharmacologic prophylaxis against venous thromboembolism, we characterized the epidemiology of clinically relevant bleeding in critically ill adolescents.

DESIGN

Post hoc analysis of data from a pediatric multicenter observational study of venous thromboembolism.

SETTING

Six PICUs.

PATIENTS

Adolescents 13-17 years old who received cardiac or pulmonary support for at least 48 hours were eligible. Those admitted with venous thromboembolism or receiving therapeutic anticoagulation were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Adolescents (n = 88) were followed daily for the development of any bleeding event. The severity of the event was categorized based on the definitions by the International Society on Thrombosis and Haemostasis. The frequency of clinically relevant bleeding was 29.5% (95% CI, 20.3-40.2%) or 3.7 events (95% CI, 2.5-5.4 events) per 100 patient-days. Adolescents with venous thromboembolism were more likely to develop clinically relevant bleeding (hazard ratio, 2.06; 95% CI, 1.08-3.94). Age was negatively associated with clinically relevant bleeding (hazard ratio for every 1-year increase in age: 0.68; 95% CI, 0.58-0.79). In contrast, predicted risk of mortality (hazard ratio for every 0.10 increase in risk: 1.35; 95% CI, 1.05-1.74) and admission for trauma or surgery (hazard ratio: 2.04; 95% CI, 1.21-3.44) were positively associated with clinically relevant bleeding. The association of clinically relevant bleeding with medications, interventions, or laboratory tests, including mechanical ventilation and pharmacologic prophylaxis with anticoagulation, did not reach statistical significance. Adolescents with clinically relevant bleeding stayed in the hospital longer than those without clinically relevant bleeding.

CONCLUSIONS

Clinically relevant bleeding is common in critically ill adolescents who are at high risk of venous thromboembolism. Admission for trauma or surgery can be used to stratify the risk of clinically relevant bleeding in these adolescents.

Thromboprophylaxis in Intensive Care Unit Patients: A Literature Review

Thromboembolism is a major complication in hospitalized patients. Intensive care unit (ICU) patients have a greater risk of thrombotic events due to additional risk factors such as immobilization, mechanical ventilation, and central catheters. The diagnosis and management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in critically ill patients are challenging and these conditions are associated with high mortality. Medical thromboprophylaxis with low molecular weight heparin (LMWH) as well as unfractionated heparin (UFH) has been shown to reduce the incidence of thromboembolic events in such patients. For patients with high risk of bleeding, mechanical thromboprophylaxis can be used. Literature database was conducted on Medline for articles published up to 2018 using particular search terms such as thromboprophylaxis and venous thromboembolism in ICU patients. The following review summarizes the existing data regarding thromboprophylaxis in ICU patients with special consideration to the use of mechanical prophylaxis and pharmacologic prophylaxis using heparin products.