Controlled Synthesis and Characterization of Poly[ethylene‐block‐(L,L‐lactide)]s by Combining Catalytic Ethylene Oligomerization with “Coordination‐Insertion” Ring‐Opening Polymerization

Model poly[ethylene‐block‐(L ,L ‐lactide)] (PE‐block‐PLA) block copolymers were successfully synthesized by combining metallocene catalyzed ethylene oligomerization with ring‐opening polymerization (ROP) of L ,L ‐lactide (LA). Hydroxy‐terminated polyethylene (PE‐OH) macroinitiator was prepared by means of ethylene oligomerization on rac‐dimethyl‐silylen‐bis(2‐methyl‐benz[e]indenyl)‐zirconium(IV)‐dichloride/methylaluminoxane (rac‐MBI/MAO) in presence of diethyl zinc as a chain transfer agent, and subsequent in situ oxidation with synthetic air. Poly[ethylene‐block‐(L ,L ‐lactide)] block copolymers were obtained via ring‐opening polymerization of LA initiated by PE‐OH in toluene at 100 °C mediated by tin octoate. The formation of block copolymers was confirmed by ¹H NMR spectroscopy, fractionation experiments, thermal behavior, and morphological characterization using AFM and light microscopy techniques.

     

Higher altitude leads to increased risk of venous thromboembolism after acetabular and pelvic ring injury

IntroductionThere is a high post-operative incidence of venous thromboembolisms (VTEs), specifically deep vein thrombosis (DVT) and pulmonary embolism (PE), in pelvic ring and acetabular fractures, and identification of risk factors for VTEs is crucial to decrease this highly morbid complication. High altitudes have a known physiological effect on the body that may predispose patients to developing VTEs in the postoperative period. The purpose of this study was to investigate the relationship between pelvic ring and acetabular fractures occurring at high altitudes and the development of postoperative VTEs.MethodsIn this retrospective study, the Truven MarketScan claims database was used to identify patients who underwent surgical fixation of a pelvic ring and/or acetabular fracture from January 2009 to December 2018 using Current Procedural Terminology (CPT) codes. Patient characteristics, including medical comorbidities, were collected. The zip codes of where the surgeries took place were used to determine recovery altitude and patients were separated into either the high altitude (>4000 feet) or low altitude (<100 feet) cohorts. Chi-squared and multivariate analyses were performed to investigate the association between altitude and the development of VTE postoperatively.ResultsIn total, 68,923 patients were included for analysis. At 30-days postoperatively, a higher altitude was associated with increased odds of developing a PE (OR 1.47, p = 0.019). At 90-days postoperatively, a higher altitude was associated with increased odds of DVT (OR 1.24, p = 0.029) and PE (OR 1.63, p < 0.001).ConclusionSurgical fixation of pelvic ring and acetabular fractures performed at a higher altitude (>4,000feet) are associated with increased odds of developing a PE in the first 30 days as well as developing a DVT or PE at 90 days postoperatively. Future prospective studies are needed to further elucidate the causality of altitude on the development of postoperative VTEs.     

Feasibility of an easy-to-use risk score in the prevention of venous thromboembolism and placental vascular complications in pregnant women: a prospective cohort of 2736 women

INTRODUCTION: Management of pregnant women at increased risk of venous thromboembolism (VTE) remains complex in the absence of an easy-to-use tool allowing individualised, risk-adapted prophylaxis. Our objective was to assess whether treatment based on risk score is feasible in these women. MATERIALS AND METHODS: A scoring system for VTE risk in pregnant women was developed, each score being associated with a specific treatment. This system was implemented in a prospective cohort of 2736 consecutive women delivered in our teaching hospital from July 2002 to June 2003. Thromboembolic and obstetrical outcomes during pregnancy and the early post-partum period were recorded. RESULTS: Treatment based on risk score was implemented in 2685 of the 2736 women included (98.1%). The scoring system identified 2431 women with no risk factor and 305 women (11%) with at least one risk factor. Eight women not at risk (0.3%, [95% CI: 0.1-0.5]) and one at risk (0.4%, [95% CI: 0-1.1]) experienced a VTE. This low event rate precluded estimation of the discriminatory power of the score. However, the benefit of the scoring system was evaluated indirectly by assessing VTE incidence in the 46 women at risk in whom it was not used (15.2%, [95% CI: 4.8-25.6]). CONCLUSIONS: Our simple scoring system offers an easily implemented procedure for risk-based VTE prophylaxis of pregnant women and the proposed therapeutic strategy appears to be effective and safe in reducing VTE. The discriminatory power of the score is currently being evaluated in a randomized, controlled trial.     

Flow cytometric detection of endothelial microparticles (EMP): Effects of centrifugation and storage alter with the phenotype studied

Introduction

Endothelial microparticles (EMP) are released into the circulation in case of endothelial disturbance, and are therefore increasingly investigated as a biomarker reflecting disease activity. Numerous pre-analytic methods have been proposed for their flow cytometric enumeration, but standardization is still lacking. In this study we evaluated the influence of centrifugation and storage conditions on EMP quantification.

Materials and Methods

Platelet-poor plasma (PPP) from 10 healthy volunteers was prepared by centrifugation at 1 550 g for 20 minutes twice. A first aliquot of PPP was analyzed immediately, a second after storage at 4 °C for 7 hours. A third and fourth aliquot were snap-frozen and stored at -80 °C for 7 and 28 days. A final aliquot was further centrifuged at 10 000 g for 10 minutes and analyzed immediately. EMP were defined as CD31+CD42b-, CD62E+, CD144+ or CD144+CD105+ particles, smaller than 1.0 µm.

Results

High speed centrifugation led to a significant loss of CD31+CD42b- EMP (p = 0.004). A good correlation between PPP and high speed centrifuged PPP was only found for CD144+ EMP (Kendall tau b = 0.611, p = 0.025).Storage at 4 °C did not affect EMP quantification. However, freezing at -80 °C increased CD31+CD42b- and CD62E+ EMP counts, and lowered CD144+ EMP (p < 0.05). Nevertheless, the agreement among the different storage conditions was relatively good (Kendall coefficient of concordance > 0.487; p < 0.05).

Conclusion

The flow cytometric detection of EMP varies with the centrifugation protocol and the storage method used, and these changes also depend on the phenotype studied. The results of this study caution against comparing study results gathered with different EMP laboratory protocols.     

Increased Risk of Deep Vein Thrombosis and Pulmonary Thromboembolism in Patients with Spinal Cord Injury: A Nationwide Cohort Prospective Study

Background

We investigated the effect of spinal cord injury (SCI) on the development of deep vein thrombosis (DVT) and pulmonary thromboembolism (PE) by conducting a nationwide longitudinal cohort study.

Methods

We studied the entire hospitalized population in Taiwan for the 1998–2008 period, with a follow-up period extending to the end of 2010. We identified SCI patients using the Taiwan National Health Insurance Research Database (NHIRD), and selected a cohort that was 1:4 frequency-matched by age (5-y span), sex, and index year from the general population. We analyzed the risks of DVT and PE using Cox proportional-hazards regression models, which included the demographic variables of sex, age, and comorbidities.

Results

A total of 47,916 SCI patients (62.7% men, mean age of 50.0 y) and 191,664 controls were followed for 308,266 and 1,341,169 person-years, respectively. The adjusted hazard ratio (HR) of DVT and PE development was 2.46-fold and 1.57-fold among the SCI patients, respectively. The highest risk of DVT and PE developed within 3 months after an SCI occurred (HR: 16.9 and 3.64, respectively). The adjusted HR of DVT and PE rose markedly with increasing age. The adjusted HR of DVT was highest among C-spine SCI patients, and the adjusted HR of PE was highest among T-spine SCI patients.

Conclusion

This nationwide prospective cohort study demonstrated that the risk of DVT and PE increased significantly in SCI patients compared with that of the general population. The highest risk of DVT and PE developed within 3 months after an SCI occurred.     

Roux-en-Y gastric bypass for nonobese patients with uncontrolled type 2 diabetes: a long-term evaluation

BackgroundThere is growing evidence that the impact of Roux-en-Y gastric bypass (RYGB) on type 2 diabetes (T2D) occurs regardless of the amount of weight loss. Taking this background into consideration, it is plausible to study this procedure in individuals with lower body mass index (BMI) under clinical treatment failure for uncontrolled T2D.ObjectivesTo elucidate the long-term impact of RYGB on T2D regression in a non-obese population.SettingHospital das Clínicas, Federal University of Pernambuco, Brazil.MethodsTwelve patients with BMI 25 to 30 kg/m² and inadequately controlled T2D underwent RYGB and were followed up for 6 years. Fasting plasma glucose, glycated hemoglobin, BMI, and the use of insulin and/or oral hypoglycemic agents were assessed. Each variable was analyzed in 3 distinct moments: preoperative evaluation, 2-year postoperative follow-up (2-PO), and 6-year postoperative follow-up (6-PO).ResultsThere were no cases of early or late mortality. Mean BMI at preoperative evaluation, 2-PO, and 6-PO were 28.1 ± 1.2; 23.2 ± 2.4; and 24.7 ± 3.1, respectively. The lowest BMI at 6-PO was 19.1 kg/m². Complete remission of T2D was achieved in 16.7%, partial remission in another 16.7%, glycemic control in 25%, and glycemic improvement in 25% of the sample at 6-PO; 16.7% did not present positive glycemic outcomes. Only 1 patient needed to resume insulin administration between 2-PO and 6-PO.ConclusionsRYGB was found to be safe and effective in treating uncontrolled T2D in non-obese patients, providing improvements in the glycemic patterns in 83.4% of our sample.     

The effect of thoracoscopy upon the repair of pectus excavatum

Background/aims

The Nuss procedure is the most commonly performed operation to correct pectus excavatum (PE). Thoracoscopic assistance has been anecdotally noted to improve the safety of this operative approach. This study aimed to compare complications and clinical outcomes before and after the introduction of thoracoscopy in a single-center.

What Are Drivers of Readmission for Readmission-Requiring Venous Thromboembolic Events After Primary Total Hip Arthroplasty? An Analysis of 544,443 Cases

BackgroundVenous thromboembolism (VTE) is a potential postoperative complication after total hip arthroplasty (THA). These events present with a range of severity, and some require readmission. The present study aimed to identify unexplored risk factors for severe VTE that lead to hospital readmission.MethodsThe Agency of Healthcare Research and Quality’s National Readmissions Database was retrospectively queried for all patients who underwent primary THA (January 2016 to December 2018). Study population included patients who were readmitted for VTE within 90 days after an elective THA. Bivariate and multivariate regression analyses were performed using patient demographics, insurance status, elective nature of the surgery, healthcare institution characteristics, and baseline comorbidities.ResultsHigher risk of readmission for VTE was evident among elderly (71-80 years vs <40 years: odds ratio [OR] 1.7, 95% confidence interval [CI] 1.3-2.2, P = .0002), male patients (OR 1.2, 95% CI 1.2-1.3). Nonelective THAs were associated with markedly higher odds of readmission for VTE (OR 20.5, 95% CI 18.9-22.2), peripheral vascular disease (OR 1.2, 95% CI 1.1-1.4), lymphoma (OR 1.5, 95% CI 1.1-2.1), metastatic cancer (OR 1.8, 95% CI 1.4-2.2), obesity (OR 1.5, 95% CI 1.4-1.6), and fluid-electrolyte imbalance (OR 1.1, 95% CI 1.0-1.2). Home health care (OR 0.8, 95% CI 0.7-0.8) and discharge to skilled nursing facility (OR 0.7, 95% CI 0.7-0.8) had lower odds of readmission for VTE vs unsupervised home discharge, while insurance type was not a significant driver(P > .05).ConclusionOne in 135 THA patients is likely to experience a VTE requiring readmission after THA. Male patients, age >70 years, and specific baseline comorbidities increase such risk. Furthermore, discharge to a supervised setting mitigated the risk of VTE requiring readmission compared to unsupervised discharge. As VTE prophylaxis protocols continue to evolve, these patients may require optimized perioperative care pathways to mitigate VTE complications.