Cost-effectiveness of prolonged thromboprophylaxis after cancer surgery

The efficacy of atorvastatin on inflammation and coagulation markers in high-risk thrombotic cancer patients undergoing chemotherapy: a randomized controlled trial

BACKGROUND

Deep vein thrombosis (DVT) is a prevalent complication associated with malignancy. Clinical use of thromboprophylaxis is recommended, however its usage is limited due to bleeding complications, more cost associated, and reluctance to receive anticoagulant injections. Rivaroxaban a relatively easy to administer anticoagulant but it has a risk of bleeding and is expensive. Inflammation is the important factor in pathogenesis of cancer-associated thrombosis. Statins have the anti-inflammatory property that could decrease proinflammatory cytokines. Consequently, statins may be used as thromboprophylaxis for cancer patients receiving chemotherapy.

OBJECTIVE

To provide comparison between atorvastatin and rivaroxaban on affecting inflammatory biomarkers (interleukin 6 [IL-6], C reactive protein [CRP]) and coagulation activation biomarkers (Tissue Factor [TF], prothrombin fragment 1 + 2 [F1 + 2], D-Dimer) in cancer patients at high risk of thrombosis receiving chemotherapy.

METHODS

A randomized controlled study that was double-blinded and involved high-risk cancer patients undergoing chemotherapy. For up to ninety days, participants were randomized to receiver either atorvastatin 20 mg or rivaroxaban 10 mg daily. The level of plasma of IL-6, CRP, TF, F1 + 2, and D-dimer were assessed 24 h before chemotherapy, 30, 60, and 90 day after chemotherapy. The latest observation carried forward (LOCF) approach was used to examine the data. The laboratory results were evaluated using an independent T test or Mann-Whitney U test prior to and after chemotherapy.

RESULTS

Eighty-six randomized patients were enrolled, although both groups showed a decreasing trend in plasma level of IL-6, CRP, TF, F1 + 2, and D-dimer, there were no significant differences between the two groups (p > 0.05). In the atorvastatin group, there was a significant correlation between delta level of IL-6 and F1 + 2 (r = 0.313, p = 0.043) and delta level of CRP and F1 + 2 (r = 0.398, p = 0.009), whereas in the rivaroxaban group there was a significant correlation between delta CRP and D-dimer level (r = 0.387, p = 0.009).

CONCLUSION

Atorvastatin decreases IL-6 and CRP level, which also decreases F1 + 2 level. Atorvastatin did not substantially differ from rivaroxaban in decreasing plasma levels of inflammatory biomarkers IL-6, CRP, and coagulation activation biomarkers TF, F1 + 2, D-dimer in high-risk cancer patients undergoing chemotherapy.

TRIAL REGISTRATION

ISRCTN71891829, Registration Date: 17/12/2020.

Variations in Perioperative Thromboprophylaxis Practices: Do the Guidelines Need a Closer Look?

Background

In 2022, the American Association for Thoracic Surgery (AATS) and the European Society of Thoracic Surgeons (ESTS) published joint guidelines regarding the timing, duration, and choice of agent for perioperative venous thromboembolism prophylaxis for thoracic cancer patients. Now, 1 year after their release, we looked to assess practices and general adherence to these recommendations.

Methods

We conducted a survey among board-certified/board-eligible thoracic surgeons in the United States, between July and October 2023.

Results

A total of 103 board-certified thoracic surgeons responded to the survey. Over half of the surgeons reported using preoperative chemical thromboprophylaxis routinely for lobectomy/sublobar resections (56.3%), pneumonectomy/extended lung resections (64.1%), and esophagectomy (67%). Over two thirds of thoracic surgeons limited the duration of postoperative chemical thromboprophylaxis to the patient's length of hospital stay and never administered chemoprophylaxis post-discharge. Among surgeons who always continued chemical thromboprophylaxis post-discharge, low-molecular-weight heparin (LMWH) was the most commonly used agent (>70%), followed by direct oral anticoagulants (13.8%-16.7%). Only 33.3% of surgeons prescribing post-discharge chemical thromboprophylaxis after lobectomy/sublobar resections continued prophylaxis up to 4 weeks postoperatively.

Conclusions

Contrary to the 2022 joint AATS/ESTS guidelines, the majority of surveyed thoracic surgeons in the United States do not routinely prescribe postoperative thromboprophylaxis after lung and esophageal cancer resections. The dogma of routine extended thromboprophylaxis must be reevaluated as modern minimally invasive thoracic surgery allows for very earlier ambulation and enhanced recovery. There is a need for randomized controlled trials exploring the utility of extended thromboprophylaxis and newer agents such as direct oral anticoagulants.

Extended-duration thromboprophylaxis following major abdominopelvic surgery - For everyone or selected cases only?

Major abdominopelvic surgery is an important risk factor for postoperative venous thromboembolism (VTE). VTE is the leading cause of 30-day postoperative mortality in patients with cancer undergoing major abdominopelvic surgery. Randomized controlled trials have shown that extended duration thromboprophylaxis using a low molecular weight heparin or a direct oral anticoagulant significantly decreases the risk of overall VTE (symptomatic events and asymptomatic deep vein thrombosis). Hence, several clinical practice guidelines suggest the use of extended duration thromboprophylaxis for all high-risk patients undergoing major abdominopelvic surgery. Despite these recommendations by clinical practice guidelines, adoption of extended duration thromboprophylaxis in clinical practice remains low and clinical equipoise seems to persist. In this narrative review, we aim is to highlight and summarize the reasons that may explain discrepancy between clinical guideline recommendations and current practice regarding extended duration thromboprophylaxis in this patient population. We also aim to review different personalized approaches based on patients' individualized risk of VTE that may foster shared decision making and improve patient outcomes by reducing decisional conflict, increasing patient knowledge, and increasing risk perception accuracy.

Utility of plasma D-dimer for diagnosis of venous thromboembolism after hepatectomy

BACKGROUND

Venous thromboembolism (VTE) is a potentially fatal complication of hepatectomy. The use of postoperative prophylactic anticoagulation in patients who have undergone hepatectomy is controversial because of the risk of postoperative bleeding. Therefore, we hypothesized that monitoring plasma D-dimer could be useful in the early diagnosis of VTE after hepatectomy.

AIM

To evaluate the utility of monitoring plasma D-dimer levels in the early diagnosis of VTE after hepatectomy.

METHODS

The medical records of patients who underwent hepatectomy at our institution between January 2017 and December 2020 were retrospectively analyzed. Patients were divided into two groups according to whether or not they developed VTE after hepatectomy, as diagnosed by contrast-enhanced computed tomography and/or ultrasonography of the lower extremities. Clinicopathological factors, including demographic data and perioperative D-dimer values, were compared between the two groups. Receiver operating characteristic curve analysis was performed to determine the D-dimer cutoff value. Univariate and multivariate analyses were performed using logistic regression analysis to identify significant predictors.

RESULTS

In total, 234 patients who underwent hepatectomy were, of whom (5.6%) were diagnosed with VTE following hepatectomy. A comparison between the two groups showed significant differences in operative time (529 vs 403 min, P = 0.0274) and blood loss (530 vs 138 mL, P = 0.0067). The D-dimer levels on postoperative days (POD) 1, 3, 5, 7 were significantly higher in the VTE group than in the non-VTE group. In the multivariate analysis, intraoperative blood loss of > 275 mL [odds ratio (OR) = 5.32, 95% confidence interval (CI): 1.05-27.0, P = 0.044] and plasma D-dimer levels on POD 5 ≥ 21 μg/mL (OR = 10.1, 95%CI: 2.04-50.1, P = 0.0046) were independent risk factors for VTE after hepatectomy.

CONCLUSION

Monitoring of plasma D-dimer levels after hepatectomy is useful for early diagnosis of VTE and may avoid routine prophylactic anticoagulation in the postoperative period.

The effectiveness of atorvastatin for the prevention of deep vein thrombosis in cancer patients undergoing chemotherapy : A randomised controlled trial: open label

BACKGROUND

Deep vein thrombosis (DVT) is a common complication in cancer. Although thromboprophylaxis in cancer patients is recommended by the guidelines, clinicians' use of thromboprophylaxis remains limited due to cost, bleeding complications, and reluctance to give injectable anticoagulants. Inflammation plays essential roles in the pathogenesis of cancer-associated thrombosis. Owing to its ability to decrease proinflammatory cytokines, statins have anti-inflammatory properties. Thus, statins can be possibly utilized as thromboprophylaxis therapy in cancer patients undergoing chemotherapy.

OBJECTIVE

To compare the effectiveness of atorvastatin and rivaroxaban for DVT prevention in high-risk thrombosis patients with cancer undergoing chemotherapy.

METHODS

Double-blind, randomized controlled trial involving cancer patients with high-risk of thrombosis undergoing chemotherapy. We randomly assigned patients without deep-vein thrombosis at screening to receive atorvastatin 20 mg or rivaroxaban 10 mg daily for up to 90 days. Doppler ultrasonography was performed 90 days following chemotherapy to diagnose DVT. Average cost-effectiveness analysis was performed to analyze the cost of atorvastatin compared to rivaroxaban.

RESULTS

Of the eighty six patients who underwent randomization, primary efficacy end point was observed in 1 of 42 patients (2.3%) in the atorvastatin group and in 1 of 44 (2.2%) in the rivaroxaban group (Odds Ratio [OR], 0.953; 95% confidence interval [CI], 0.240 to 3.971; p = 1.000). There was a significant difference in the incidence of major bleeding, 2 of 42 patients (4.8%) in the atorvastatin group and 12 of 44 (27.3%) in the rivaroxaban group (OR, 0.257; 95% CI, 0.07 to 0.94; p = 0.007). The average cost-effectiveness ratio of using atorvastatin was lower than that of rivaroxaban.

CONCLUSION

Atorvastatin did not differ significantly from rivaroxaban in reducing the incidence of DVT, lower bleeding risk, and cost-effectiveness for thromboprophylaxis in high-risk thrombosis patients with cancer undergoing chemotherapy. The presence of limited statistical power and wide confidence intervals in this study needs further study to strengthen the efficacy of atorvastatin as DVT prophylaxis in cancer patients.

TRIAL REGISTRATION

ISRCTN71891829, Registration Date: 17/12/2020.

Correlation of Inflammation and Coagulation Markers with the Incidence of Deep Vein Thrombosis in Cancer Patients with High Risk of Thrombosis

Background

Deep vein thrombosis (DVT) is a common complication and the second leading cause of death in cancer patients. Pro-inflammatory stimuli in the cancer microenvironment induce nuclear factor kappa B (NF-κB) signaling pathway that plays an integral role in immunothrombosis mechanism.

Objective

To investigate the role of inflammatory and coagulation biomarkers in the development of DVT in cancer patients with high risk of thrombosis (Khorana score ≥2).

Subjects and methods

This study was a cross-sectional study at Dr. Kariadi General Hospital. The serum levels of proinflammatory cytokines, ie, NF-κB, interleukin-6 (IL-6), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and coagulation biomarkers, ie, tissue factor (TF), prothrombin fragment F1+2 (F1+2), fibrinogen and D-dimer were measured in newlydiagnosed cancer patients with a highrisk of thrombosis. Color duplex sonography was used for DVT screening.

Results

From January to November 2021, there were 83 eligible patients. DVT was confirmed in 8 subjects (9.63%). Univariate analysis revealed a significant difference between the median age of patients with DVT compared to non-DVT patients, 49.5 years (range: 23–60 years) and 42 years (range: 19–60 years), with p=0.046. D-dimer level was higher in DVT patients [(6.020 µg/L, range 2.090–20.000) vs (1.940 µg/L, range 270–20.000), p=0.005]. Multivariate analysis revealed age and D-dimer were significantly correlated with DVT incidence. In all patients, there were significant positive correlations between several inflammatory and coagulation activation parameters, which were IL-6 with D-dimer and F1+2, CRP with F1+2 and D-dimer as well as TNF-α with F1+2. However, these findings were not shown in DVT patients.

Conclusion

In cancer patients with a high risk of thrombosis, age and D-dimer level are the significant variables towards the incidence of DVT. In patients with DVT, there was no significant correlation between inflammatory and coagulation activation parameters.

Cost-effectiveness of Venous Thromboembolism Prophylaxis After Hospitalization in Patients With Inflammatory Bowel Disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a 2- to 3-fold greater risk of venous thromboembolism (VTE) than patients without IBD, with increased risk during hospitalization that persists postdischarge. We determined the cost-effectiveness of postdischarge VTE prophylaxis among hospitalized patients with IBD.

METHODS

A decision tree compared inpatient prophylaxis alone vs 4 weeks of postdischarge VTE prophylaxis with 10 mg/day of rivaroxaban. Our primary outcome was quality-adjusted life years (QALYs) over 1 year, and strategies were compared using a willingness to pay of $100,000/QALY from a societal perspective. Costs (in 2020 $USD), incremental cost-effectiveness ratios (ICERs) and number needed to treat (NNT) to prevent 1 VTE and VTE death were calculated. Deterministic 1-way and probabilistic analyses assessed model uncertainty.

RESULTS

Prophylaxis with rivaroxaban resulted in 1.68-higher QALYs per 1000 persons compared with no postdischarge prophylaxis at an incremental cost of $185,778 per QALY. The NNT to prevent a single VTE was 78, whereas the NNT to prevent a single VTE-related death was 3190. One-way sensitivity analyses showed that higher VTE risk >4.5% and decreased cost of rivaroxaban ≤$280 can reduce the ICER to <$100,000/QALY. Probabilistic sensitivity analyses favored prophylaxis in 28.9% of iterations.

CONCLUSIONS

Four weeks of postdischarge VTE prophylaxis results in higher QALYs compared with inpatient prophylaxis alone and prevents 1 postdischarge VTE among 78 patients with IBD. Although postdischarge VTE prophylaxis for all patients with IBD is not cost-effective, it should be considered in a case-by-case scenario, considering VTE risk profile, costs, and patient preference.

Venous thromboembolism in benign esophageal surgery patients: potential cost effectiveness of Caprini risk stratification

BACKGROUND

The Caprini risk assessment model (RAM) stratifies surgical patients for prescription of post-discharge extended heparin prophylaxis to reduce post-operative venous thromboembolism (VTE) events. The average cost for treatment of a VTE event is $15,123. The 30-day post-operative VTE rate after benign esophageal procedures is < 0.8% per the Society of Thoracic Surgeons database. We hypothesized that the financial cost of selective extended prophylaxis in patients undergoing surgery for benign esophageal disease would exceed the cost of treating these rare events and therefore use of risk stratification for extended prophylaxis would not be beneficial.

METHODS

All patients undergoing operations for benign esophageal pathology from July 2014 to May 2019 were reviewed. Patients designated as moderate or high risk for VTE were prescribed a 10- or 30-day post-operative course of extended prophylaxis with low-molecular weight heparin (LMWH). VTE and adverse bleeding events were recorded for the 60-day post-operative period. The cost of LMWH was provided by the institution pharmacy.

RESULTS

Records from 154 patients were eligible for review. Caprini RAM was used for all patients with the following distribution of risk categories: low = 64.9% (100/154); moderate = 31.8% (49/154); and high = 3.2% (5/154). The average cost of extended prophylaxis at discharge for the moderate-risk group was $121.23, while the high-risk group was $446.46. There were no 60-day VTE or adverse bleeding events recorded.

CONCLUSIONS

The majority of patients undergoing surgical therapy were at low risk of post-operative VTE event, with only 35% requiring extended VTE prophylaxis at time of discharge. When compared with the average cost of treatment for a VTE event, the cost of extended prophylaxis per patient in moderate or high-risk groups is substantially lower. In the era of cost-containment, risk stratification and extended prophylaxis may reduce healthcare costs and warrant future investigations.

Cost-Effectiveness of Extended Thromboprophylaxis in Patients Undergoing Colorectal Surgery from a Canadian Health Care System Perspective

BACKGROUND

There is increasing evidence to support extended thromboprophylaxis after colorectal surgery to minimize the incidence of postdischarge venous thromboembolic events. However, the absolute number of events is small, and extended thromboprophylaxis requires significant resources from the health care system.

OBJECTIVE

This study aimed to determine the cost-effectiveness of extended thromboprophylaxis in patients undergoing colorectal surgery for malignancy or IBD.

DESIGN

An individualized patient microsimulation model (1,000,000 patients; 1-month cycle length) comparing extended thromboprophylaxis (28-day course of enoxaparin) to standard management (inpatient administration only) after colorectal surgery was constructed.

SETTINGS

The sources for this study were The American College of Surgeons National Surgical Quality Improvement Project Participant User File and literature searches.

OUTCOMES

Costs (Canadian dollars), quality-adjusted life-years, and venous thromboembolism-related deaths prevented over a 1-year time horizon starting with hospital discharge were determined. The results were stratified by malignancy or IBD.

RESULTS

In patients with malignancy, extended prophylaxis was associated with higher costs (+113$; 95% CI, 102-123), but increased quality-adjusted life-years (+0.05; 95% CI, 0.04-0.06), resulting in an incremental cost-effectiveness ratio of 2473$/quality-adjusted life-year. For IBD, extended prophylaxis also had higher costs (+116$; 95% CI, 109-123), more quality-adjusted life-years (+0.05; 95% CI, 0.04-0.06), and an incremental cost-effectiveness ratio of 2475$/quality-adjusted life-year. Extended prophylaxis prevented 16 (95% CI, 4-27) venous thromboembolism-related deaths per 100,000 patients and 22 (95% CI, 6-38) for malignancy and IBD. There was a 99.7% probability of cost-effectiveness at a willingness-to-pay threshold of 50,000$/quality-adjusted life-year. To account for statistical uncertainty around variables, sensitivity analysis was performed and found that extended prophylaxis is associated with lower overall costs when the incidence of postdischarge venous thromboembolic events reaches 1.8%.

LIMITATIONS

Significant differences in health care systems may affect the generalizability of our results.

CONCLUSIONS

Despite the rarity of venous thromboembolic events, extended thromboprophylaxis is a cost-effective strategy. See Video Abstract at http://links.lww.com/DCR/A976. COSTO-EFECTIVIDAD DE LA TROMBOPROFILAXIS EXTENDIDA EN PACIENTES SOMETIDOS A CIRUGÍA COLORRECTAL DESDE UNA PERSPECTIVA DEL SISTEMA DE SALUD CANADIENSE:: Cada vez hay más pruebas que apoyen la tromboprofilaxis extendida después de la cirugía colorrectal para minimizar la incidencia de eventos tromboembólicos venosos después del alta hospitalaria. Sin embargo, el número absoluto de eventos es pequeño y la tromboprofilaxis extendida requiere recursos significativos del sistema médico.Determinar la rentabilidad (relación costo-efectividad) de la tromboprofilaxis extendida en pacientes sometidos a cirugía colorrectal por neoplasia maligna o enfermedad inflamatoria intestinal.Un modelo de microsimulación de paciente individualizado (1,000,000 de pacientes; ciclo de 1 mes) que compara la tromboprofilaxis extendida (curso de enoxaparina de 28 días) con el tratamiento estándar (solo para pacientes hospitalizados) después de la cirugía colorrectal.Archivo de usuario participante del Proyecto de Mejoramiento de la Calidad Quirúrgica del Colegio Nacional de Cirujanos Americanos (ACS-NSQIP) y búsquedas bibliográficas.Costos (en dólares Canadienses), años de vida ajustados por la calidad y muertes relacionadas con el tromboembolismo venoso prevenidas en un horizonte temporal de 1 año a partir del alta hospitalaria. Los resultados fueron estratificados por malignidad o enfermedad inflamatoria intestinal.En pacientes con neoplasias malignas, la profilaxis extendida se asoció con costos más altos (+113 $; IC del 95%, 102-123), pero con un aumento de la calidad de vida ajustada por años de vida (+0.05; IC del 95%, 0.04-0.06), lo que resultó en un incremento de relación costo-efectividad de 2473 $/año de vida ajustado por calidad. Para la enfermedad inflamatoria intestinal, la profilaxis extendida también tuvo costos más altos (+116 $; 95% IC, 109-123), más años de vida ajustados por calidad (+0.05; 95% IC, 0.04-0.06) y una relación costo-efectividad incremental de 2475 $/año de vida ajustado por calidad. La profilaxis prolongada evitó 16 (95% IC, 4-27) muertes relacionadas con tromboembolismo venoso por cada 100,000 pacientes y 22 (95% IC, 6-38) por malignidad y enfermedad inflamatoria intestinal, respectivamente. Hubo un 99.7% de probabilidad de costo-efectividad en un límite de disposición a pagar de 50,000 $/año de vida ajustado por calidad. Para tener en cuenta la incertidumbre estadística en torno a los variables, se realizó un análisis de sensibilidad y se encontró que la profilaxis extendida se asocia con menores costos generales cuando la incidencia de eventos tromboembólicos venosos después del alta hospitalaria alcanza 1.8%.Las diferencias significativas en los sistemas de salud pueden afectar la generalización de nuestros resultados.A pesar de la escasez de eventos tromboembólicos venosos, la tromboprofilaxis extendida es una estrategia rentable. Vea el video del resumen en http://links.lww.com/DCR/A976.

Risk factors for post-discharge venous thromboembolism in patients undergoing colorectal resection: a NSQIP analysis

BACKGROUND

Extended thromboprophylaxis after abdominal and pelvic cancer surgery to prevent venous thromboembolic events (VTE) is recommended but adherence is sub-optimal. Identifying patients at highest risk for post-discharge events may allow for selective extended thromboprophylaxis. The aim of our study was to identify the different risk factors of venous thromboembolism for in-hospital and post-discharge events.

METHODS

The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) 2012-2016 database was queried for all patients having colorectal resection. Primary outcome was postoperative VTE occurrence within 30 days. A multinomial logistic regression was performed to identify in-hospital and post-discharge predictors of VTE, adjusting for potential confounders.

RESULTS

Out of 260,258 patients, 5381 (2.1%) developed VTE. A total of 3442 (1.3%) were diagnosed during the initial hospital stay and 1929 (0.8%) post-discharge. Risk factors for in-hospital and post-discharge VTE were different as patients with an in-hospital event were more likely to be older, male, known for preoperative steroid use, have poor functional status, significant weight loss, preoperative sepsis, prolonged operative time, undergoing an emergency operation. In the post-discharge setting, steroid use, poor functional status, preoperative sepsis, and postoperative complications remained significant. Postoperative complications were the strongest predictor of in-hospital and post-discharge VTE. Patients with inflammatory bowel disease had a higher risk of VTE than patients with malignancy for both in-patient and post-discharge events.

CONCLUSIONS

Patients at high-risk for post-discharge events have different characteristics than those who develop VTE in-hospital. Identifying this specific subset of patients at highest risk for post-discharge VTE may allow for the selective use of prolonged thromboprophylaxis.

Extended venous thromboembolism prophylaxis after colorectal cancer surgery: the current state of the evidence

There is level one evidence to support combined mechanical and chemical thromboprophylaxis for 7-10 days after colorectal cancer surgery, but there remains a paucity of data to support extended prophylaxis after discharge. The aim of this clinical review is to summarise the currently available evidence for extended venous thromboprophylaxis after elective colorectal cancer surgery. Clinical review of the major clinical guidelines and published clinical data evaluating extended venous thromboprophylaxis after elective colorectal cancer surgery. Five major guideline recommendations are outlined, and the results of the five published randomised controlled trials are summarised and reviewed with a specific focus on the efficacy and cost-effectiveness of extended heparin prophylaxis to prevent clinically relevant post-operative venous thromboembolism (VTE) after colorectal cancer surgery. Extended VTE prophylaxis after colorectal cancer surgery reduces the incidence of asymptomatic screen detected deep venous thrombosis (DVT) only, with no demonstrable reduction in symptomatic DVT, symptomatic PE, or VTE related death. Evidence for cost-effectiveness is limited. As the incidence of clinical VTE is very low in this patient subgroup overall, future research should be focused on higher risk patient subgroups in whom a reduction in VTE may be both more demonstrable and clinically relevant.

Impact of thromboprophylaxis across the US acute care setting

Background

The risk of venous thromboembolism (VTE) can be reduced by appropriate use of anticoagulant prophylaxis. VTE prophylaxis does, however, remain substantially underused, particularly among acutely ill medical inpatients. We sought to evaluate the clinical and economic impact of increasing use of American College of Chest Physicians (ACCP)-recommended VTE prophylaxis among medical inpatients from a US healthcare system perspective.

Methods and Findings

In this retrospective database cost-effectiveness evaluation, a decision-tree model was developed to estimate deaths within 30 days of admission and outcomes attributable to VTE that might have been averted by use of low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH). Incremental cost-effectiveness ratio was calculated using “no prophylaxis” as the comparator. Data from the ENDORSE US medical inpatients and the US nationwide Inpatient Sample (NIS) were used to estimate the annual number of eligible inpatients who failed to receive ACCP-recommended VTE prophylaxis. The cost-effectiveness analysis indicated that VTE-prevention strategies would reduce deaths by 0.5% and 0.3%, comparing LMWH and UFH strategies with no prophylaxis, translating into savings of $50,637 and $25,714, respectively, per death averted. The ENDORSE findings indicated that 51.1% of US medical inpatients were at ACCP-defined VTE risk, 47.5% of whom received ACCP-recommended prophylaxis. By extrapolating these findings to the NIS and applying cost-effectives analysis results, the full implementation of ACCP guidelines would reduce number of deaths (by 15,875 if using LMWH or 10,201 if using UFH), and was extrapolated to calculate the cost reduction of $803M for LMWH and $262M for UFH.

Conclusions

Efforts to improve VTE prophylaxis use in acutely ill inpatients are warranted due to the potential for reducing VTE-attributable deaths, with net cost savings to healthcare systems.

Recent advances in glycerol polymers: chemistry and biomedical applications

Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, the underlying chemistry of glycerol that provides access to a range of monomers for subsequent polymerizations is described. Then, the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth are reviewed. Next, several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity are described. Fourth, the growing market opportunity for the use of polymers in medicine is described. Finally, the findings are concluded and summarized, as well as the potential opportunities for continued research efforts are discussed.

Use of aspirin for the prevention of lower extremity deep venous thrombosis

Whereas aspirin is recommended and widely used to prevent arterial thrombosis, its role in the prevention of deep venous thrombosis is not well defined. Aspirin is well accepted, easy to manage with few risks and low cost, and thus ideal for thromboprophylaxis if evidence shows it is effective. Recent guidelines and large studies were reviewed. Recent guidelines include aspirin as an acceptable thromboprophylactic agent after hip and knee orthopedic surgery despite continued publication of underpowered and contradictory studies. Two large randomized controlled trials pooled together suggest that low-dose (100 mg) aspirin is a reasonable alternative to prevent recurrence of venous thromboembolism (VTE) in patients who have been treated for a first episode of unprovoked VTE. We suggest that the current practice using aspirin to prevent thromboembolism include cautious discussion of the benefits and risks of this agent before use in a patient until precise clarification of dosage and treatment length is available. Despite inclusion of aspirin in the guidelines for orthopedic surgery, there is little evidence to support its use for primary prevention of VTE. Until definitive unbiased trials are published, we suggest that aspirin remain a realistic option to use for secondary prevention of VTE, especially compared with the option of using no prophylaxis.

Defining high risk: cost-effectiveness of extended-duration thromboprophylaxis following major oncologic abdominal surgery

PURPOSE

Extended-duration thromboprophylaxis (EDTPPX) is the practice of prescribing antithrombotic therapy for 21 days after discharge, commonly used in surgical patients who are at high risk for venothromboembolism (VTE). While guidelines recommend EDTPPX, criteria are vague due to a paucity of data. The criteria can be further informed by cost-effectiveness thresholds. This study sought to determine the VTE incidence threshold for the cost-effectiveness of EDTPPX compared to inpatient prophylaxis.

METHODS

A decision tree was used to compare EDTPPX for 21 days after discharge to 7 days of inpatient prophylaxis with base case assumptions based on an abdominal oncologic resection without complications in an otherwise healthy individual. Willingness to pay was set at $50,000/quality-adjusted life year (QALY). Sensitivity analyses were performed to assess uncertainty within the model, with particular interest in the threshold for cost-effectiveness based on VTE incidence.

RESULTS

EDTPPX was the dominant strategy when VTE probability exceeds 2.39 %. Given a willingness to pay threshold of $50,000/QALY, EDTPPX was the preferred strategy when VTE incidence exceeded 1.22 and 0.88 % when using brand name or generic medication costs, respectively.

CONCLUSIONS

EDTPPX should be recommended whenever VTE incidence exceeds 2.39 %. When post-discharge estimated VTE risk is 0.88-2.39 %, patient preferences about self-injections and medication costs should be considered.

Prediction of venous thromboembolism after surgery for colorectal cancer: a prevention paradigm

SUMMARY Colorectal cancer patients are at elevated risk for venous thromboembolism, especially in the postsurgical setting. Many risk factors particular to colorectal patients have been identified including malignancy-associated hypercoagulability, colorectal cancer in its own right, chemotherapy, obesity and operative approach. While initiatives aimed at improving inpatient prophylaxis have been effective, the period of risk extends far beyond the inpatient episode suggesting that this approach is inadequate. The prolonged hypercoaguable state combined with the efficacy of extended-duration thromboprophylaxis has led to international consensus guidelines suggesting its implementation. International compliance is low, highlighting the need for greater educational efforts. Risk stratification using identified predictors of venous thromboembolism may improve guideline delivery through a more targeted approach.

Postoperative decreased levels of D-dimer in patients with gynecologic cancer with enoxaparin and fondaparinux thromboprophylaxis

The purpose of the present study was to evaluate the effects of enoxaparin (ENO) and fondaparinux (FPX) on postoperative plasma D-dimer levels and risk factors associated with postoperative venous thromboembolism (VTE) and pulmonary thromboembolism (PTE) in patients with gynecologic cancer. For this study, 434 patients with gynecologic cancer were recruited and a surgical treatment strategy was employed. Plasma D-dimer levels were measured prior to surgery, as well as on a schedule up to 3 weeks postoperatively and again after day 28. Patients with clinical signs and elevation of the plasma D-dimer level underwent multidetector row computed tomography. The D-dimer value was significantly lower in patients with ENO or FPX on postoperative days 3–10 compared to patients with gynecologic cancers who were not receiving ENO or FPX. The D-dimer value was significantly lower in patients with FPX compared to patients with ENO on postoperative days 5–7. The D-dimer value on postoperative day 3, the use of erythropoiesis-stimulating agents (ESAs), advancing age and non-O blood group were independent risk factors for postoperative VTE. The D-dimer value on postoperative day 3 and the use of ESAs were independent risk factors for postoperative PTE. The postoperative D-dimer value was significantly lower in patients with gynecologic cancer who were administered ENO or FPX compared to patients were not administered either ENO or FPX. The use of ESAs and high plasma D-dimer levels on postoperative day 3 were independent risk factors for postoperative VTE and PTE.

Effect of ovarian tumor characteristics on venous thromboembolic risk

OBJECTIVE

Deep venous thrombosis and pulmonary embolism are common in patients with epithelial ovarian cancer, resulting in high costs associated with diagnosis and treatment. I aimed to identify subtypes of epithelial ovarian cancer that pose greater and lesser venous thromboembolism (VTE) risk.

METHODS

I assessed the outcomes of 641 patients with epithelial ovarian, fallopian tube, and primary peritoneal cancer over a ten-year period. All inpatient, outpatient, and pathology records were reviewed. The rates at which people were evaluated for and diagnosed with venous thromboembolism were assessed.

RESULTS

Of the 641 cases, 30.0% underwent an imaging test to evaluate for deep venous thrombosis (DVT) and 21.7% underwent testing for pulmonary embolism (PE). A 10.8% of all subjects were diagnosed with DVT and 7.2% were diagnosed with PE. Borderline tumors and mucinous showed a strikingly low rate of both DVT and PE. Clear cell and high-grade undifferentiated adenocarcinomas were the most likely to result in VTE. In a multivariate model, pathologic subtype was not only a significant predictor of VTE, but was the single best predictor of VTE.

CONCLUSION

Clear cell and undifferentiated pathology in epithelial ovarian carcinomas is associated with a higher VTE risk. The underlying reason for this may related to differences in tumor biology. By identifying low and high risk groups, I may both better conserve medical resources and design more effective thromboprophylaxis for my patients.

Inclusion of compliance and persistence in economic models: past, present and future

Economic models are developed to provide decision makers with information related to the real-world effectiveness of therapeutics, screening and diagnostic regimens. Although compliance with these regimens often has a significant impact on real-world clinical outcomes and costs, compliance and persistence have historically been addressed in a relatively superficial fashion in economic models. In this review, we present a discussion of the current state of economic modelling as it relates to the consideration of compliance and persistence. We discuss the challenges associated with the inclusion of compliance and persistence in economic models and provide an in-depth review of recent modelling literature that considers compliance or persistence, including a brief summary of previous reviews on this topic and a survey of published models from 2005 to 2012. We review the recent literature in detail, providing a therapeutic-area-specific discussion of the approaches and conclusions drawn from the inclusion of compliance or persistence in economic models. In virtually all publications, variation of model parameters related to compliance and persistence was shown to have a significant impact on predictions of economic outcomes. Growing recognition of the importance of compliance and persistence in the context of economic evaluations has led to an increasing number of economic models that consider these factors, as well as the use of more sophisticated modelling techniques such as individual simulations that provide an avenue for more rigorous consideration of compliance and persistence than is possible with more traditional methods. However, we note areas of continuing concern cited by previous reviews, including inconsistent definitions, documentation and tenuous assumptions required to estimate the effect of compliance and persistence. Finally, we discuss potential means to surmount these challenges via more focused efforts to collect compliance and persistence data.

Changes in soluble fibrin levels during the perioperative period of gynecologic cancer surgery

The purpose of this study was to evaluate the changes in plasma soluble fibrin (SF) levels over time in gynecologic cancer patients following surgery. Furthermore, we examined the duration of the coagulation stage and determined a suitable duration for which thromboprophylaxis with anticoagulant agents should be administered. We retrospectively studied 311 patients with invasive gynecologic cancer who underwent surgery at Okayama University Hospital, Japan. The plasma SF levels were measured serially prior to the operation and on postoperative days 0, 1, 3, 5, 7, 10, 14, 21 and 28. The plasma SF levels increased rapidly, peaked on postoperative day 1 and then decreased. The SF levels of patients with venous thromboembolism (VTE) were significantly different from those of VTE-negative patients on postoperative days 0-10. The SF levels on each day did not significantly differ between patients treated with chemical anticoagulants and those treated mechanically. The plasma SF levels were elevated (≥7.0 μg/ml) in 159 of the 311 patients (51.1%) on one of the days when these levels were measured. Among the patients with elevated plasma SF levels, 110 patients (69.2%) peaked on days 0-3 and only 9 patients (5.7%) peaked on days 21-28. Although only 1 of the 14 patients (7.1%) who showed peak levels on day 14 had undergone chemotherapy following surgery, 8 of the 9 patients (88.9%) whose levels peaked on days 21-28 had undergone chemotherapy following surgery (P= 0.0002). In conclusion, the plasma SF levels increased rapidly, peaked on postoperative day 1 and then decreased. These levels peaked within 14 days of surgery in most cases. Therefore, chemical thromboprophylaxis may be administered for at least up to 14 days following surgery.

Screening for blunt cerebrovascular injuries is cost-effective

BACKGROUND

Screening for blunt carotid and vertebral injury (BCVI) is increasing without a clear understanding of whether the chosen screening approach is cost-effective. We hypothesized that screening for BCVI using computed tomography angiography (CTA) was cost-effective in populations at high risk for BCVI.

METHODS

A decision analysis was performed modeling current BCVI screening approaches: no screening, duplex ultrasound, magnetic resonance angiography, angiography, and CTA. Treatment options included antiplatelet therapy, anticoagulation, stents for pseudoaneurysm, and no treatment. Probability estimates for incidence of injury and stroke, sensitivity and specificity of the screening modality, and type of treatment were taken from published data. Average wholesale price and medicare reimbursement costs were used. Two populations were analyzed; high-risk and overall blunt trauma populations. Two perspectives were taken; societal (including lifetime stroke costs) and institutional (ignoring lifetime stroke costs).

RESULTS

In the high-risk population, from a societal perspective, CTA has the lowest cost and stroke rate; $3,727 per patient screened with a 1% stroke rate. No treatment has the highest cost and stroke rate. From an institutional perspective, no screening is the least costly option but has an 11% stroke rate. Duplex ultrasound is the most cost-effective screening modality; $8,940 per stroke prevented.

CONCLUSION

From the societal perspective, CTA is the most cost-effective screening strategy for patients at high risk for BCVI. From an institutional perspective, CTA prevents the most strokes at a reasonable cost.

Poly(carbonate-ester)s of dihydroxyacetone and lactic acid as potential biomaterials

The synthesis of new polymeric biomaterials using biocompatible building blocks is important for the advancement of the biomedical field. We report the synthesis of statistically random poly(carbonate-ester)s derived from lactic acid and dihydroxyacetone by ring-opening polymerization. The monomer mole feed ratio and initiator concentration were adjusted to create various copolymer ratios and molecular weights. A dimethoxy acetal protecting group was used to stabilize the dihydroxyacetone and was removed using elemental iodine and acetone at reflux to produce the final poly(lactide-co-dihydroxyacetone) copolymers. The characteristics of the copolymers in their protected and deprotected forms were characterized by (1)H NMR, (13)C NMR, GPC, TGA, and DSC. Hydrolytic degradation of the deprotected copolymers was tracked over an 8-week time frame. The results show that faster degradation occurred with increased carbonate content in the copolymer backbone. The degradation pattern of the copolymers was visualized using SEM and revealed a trend toward surface erosion as the primary mode of degradation.