Effectiveness of vitamin K in anticoagulation reversal for hip fracture surgery – A prospective observational study

Introduction

Vitamin K antagonists are often used for anticoagulant treatment in hip fracture patients. The optimal handling with such anticoagulants is unclear.We aimed to determine when anticoagulation reversal occurred after vitamin K administration and how often prothrombin complex concentrates (PCCs) were administered. We compared patients’ treatments and outcomes with those of a control group not receiving treatment for anticoagulation.

Patients and Methods

A total of 402 geriatric hip fracture patients were included in this observational study. We collected data on treatment for anticoagulation, time to surgery, and reasons for delay of surgery. In patients taking vitamin K antagonists, we measured the INR (international normalized ratio) on admission and prior to surgery, along with the frequency of PCC administration. Finally, we compared in-hospital mortality and complications between patient groups.

Results

A total of 62 (15%) patients received phenprocoumon prior to their fractures. Surgery was delayed in these patients compared to controls (27 h; 95%CI 23–31 vs. 16 h; 95%CI 19–19; p = 0.001), but surgery delay > 48 h (n = 5; 8%) was not due to a failure of INR reversal. The main reason for these delays was a lack of capacity for surgery. The average INR on admission was 2.1 (± 0.7; range 1.0-3.5) in patients taking phenprocoumon, which decreased to 1.3 (± 0.3; range 1.0-1.6) until surgery. PCCs were administered to 19% of patients. We found no differences in the in-hospital mortality (6.2% vs. 8.1%, p = 0.575) or complication rates (12.9% vs. 9.4%, p = 0.364).

Conclusion

The use of vitamin K seemed to be sufficient for anticoagulation reversal in geriatric hip fracture patients, and it generally led to timely surgery; despite this success, PCCs were sometimes administered for logistical reasons.     

A case series of LMWH use in pregnancy: Should trough anti-Xa levels guide dosing?

Introduction

Pregnancy is a thrombogenic state, increasing the risk for venous thromboembolism (VTE), and the risk of valve thrombosis amongst women with mechanical heart valves (MHV). While low molecular weight heparins (LMWH) are generally dosed based on weight (i.e., enoxaparin 1 mg/kg every 12 hours), data in pregnant women have shown that weight-based dosing does not consistently achieve target anti-Xa levels. In women with MHV, our practice includes titrating LMWH doses to target both trough and peak anti-Xa levels, while for those with VTE peak anti-Xa levels guide dosing.

Materials/Methods

This retrospective case series included pregnant women requiring LMWH treatment doses with at least 3 peak (+/− trough) anti-Xa levels. Our primary objective was to describe the actual LMWH dose required to achieve targeted anti-Xa levels relative to weight-based dosing in patients with MHV. Secondarily, we compared the same for VTE patients; compared actual dosing between those with MHV and VTE; and examined maternal and fetal outcomes.

Results/Conclusion

Women with MHV (N = 4) required greater than weight-based dosing of enoxaparin (1.35 mg/kg Q12H) to achieve targeted anti-Xa levels. Importantly, achieving target peak anti-Xa levels did not always ensure maintenance of minimum trough levels. VTE patients (N = 12) did not require more enoxaparin (0.96 mg/kg Q12H) than weight based dosing. MHV patients received more enoxaparin compared to VTE patients (P < 0.001). No bleeding or clotting complications were associated with LMWH administration. In pregnant women with MHV at high risk of thromboembolism, LMWH dosing guided by trough and peak anti-Xa levels should be considered.     

Recurrent venous thromboembolism while on anticoagulant therapy

There has been immense progress in the management of venous thromboembolism in recent years with increased awareness and adequate thromboprophylaxis proving successful in reducing the morbidity and mortality associated with this condition. One of the commonest complications of an initial venous thrombosis is the development of recurrent thrombosis. Unlike in the case of the first clot, the diagnosis and management of the recurrent episode remain a difficult issue. Even more challenging is the clinical situation where a new thrombus develops while the patient is being treated with anticoagulant medication for a previous clot. The clinical approach and management of these patients are complex, and require understanding of the differences in thrombus development in the different clinical circumstances.     

Anticoagulation

The increasing incidence of thrombosis in hospitalized patients in the 21st century is due to improved awareness by clinicians and more sophisticated forms of imaging. Thromboprophylaxis is now an imperative in the NHS of the UK and this combined with new, improved and safer forms of anticoagulation means that postoperative deaths from venous thromboembolic disease should become a thing of the past. In the following paper the authors review the up-to-date literature with emphasis on the newer anticoagulants that do not require blood test monitoring. We fully accept that this is a developing field and that the recognized indications for certain of these agents will change with the accumulation of further evidence.     

Electrochemical Assay of Heparin to Monitor Anticoagulation Action in Cardiovascular Patients

Complications in anticoagulation therapy and long term consequences of the post thrombotic syndromes requires a fast and powerful therapy such as heparin therapy (anticoagulation) to minimize the thrombotic effects in patients. Thus, a simple approach via electrochemical method: Differential pulse polarography (DPP) has been developed for heparin analysis as a powerful clinical tool to monitor anticoagulation action in-patient undergoing heparin therapy. The method has been standardized for determination of heparin activity over the existing methods and a very well defined characteristic reduction peak at −1.25 V in 2 M NaOH was observed for heparin. A linear relation was observed with a regression equation as y = 0.3117x + 0.8069, for 0.1 to 2.0 units/ml heparin. The developed DPP method was observed with excellent precision, accuracy and recovery in human blood plasma samples and in pharmacological formulations. The limit of detection (LOD) and limit of quantification (LOQ) noticed to be 2.04 and 6.8 units/ml respectively. The DPP results compared with pharmacological screening through average thrombin time (TT) and applied to monitor invitro anticoagulation action of heparin in healthy human subjects. Statistical analysis done to validate developed DPP method for heparin analysis and its probable clinical use to monitor anticoagulation action to treat patients suffering from various cerebrovascular disorders (CVD) by proper dosing of heparin.     

无肝素及低分子肝素在有出血倾向的血液透析患者的应用研究

目的研究无肝素及低分子肝素在有出血倾向的血液透析患者的应用安全性和有效性。方法选择伴有中、高危出血倾向的维持性血液透析(MHD)患者24例,随机分为A组12例(无肝素透析),B组12例(低分子肝素透析),观察临床出血情况,透析前后部分凝血酶活化时间、凝血酶原时间、血小板、管道及透析器凝血情况。结果透析后两组无一例出血加重,A组7例发生凝血,B组无体外凝血发生。结论无肝素与低分子两种透析抗凝方法,低分子肝素透析明显优于无肝素。     

Anticoagulation therapy prevents portal-splenic vein thrombosis after splenectomy with gastroesophageal devascularization

AIM: To compare the incidence of early portal or splenic vein thrombosis (PSVT) in patients treated with irregular and regular anticoagulantion after splenectomy with gastroesophageal devascularization.METHODS: We retrospectively analyzed 301 patients who underwent splenectomy with gastroesophageal devascularization for portal hypertension due to cirrhosis between April 2004 and July 2010. Patients were categorized into group A with irregular anticoagulation and group B with regular anticoagulation, respectively. Group A (153 patients) received anticoagulant monotherapy for an undesignated time period or with aspirin or warfarin without low-molecular-weight heparin (LMWH) irregularly. Group B (148 patients) received subcutaneous injection of LMWH routinely within the first 5 d after surgery, followed by oral warfarin and aspirin for one month regularly. The target prothrombin time/international normalized ratio (PT/INR) was 1.25-1.50. Platelet and PT/INR were monitored. Color Doppler imaging was performed to monitor PSVT as well as the effectiveness of thrombolytic therapy.RESULTS: The patients’ data were collected and analyzed retrospectively. Among the patients, 94 developed early postoperative mural PSVT, including 63 patients in group A (63/153, 41.17%) and 31 patients in group B (31/148, 20.94%). There were 50 (32.67%) patients in group A and 27 (18.24%) in group B with mural PSVT in the main trunk of portal vein. After the administration of thrombolytic, anticoagulant and anti-aggregation therapy, complete or partial thrombus dissolution achieved in 50 (79.37%) in group A and 26 (83.87%) in group B.CONCLUSION: Regular anticoagulation therapy can reduce the incidence of PSVT in patients who undergo splenectomy with gastroesophageal devascularization, and regular anticoagulant therapy is safer and more effective than irregular anticoagulant therapy. Early and timely thrombolytic therapy is imperative and feasible for the prevention of PSVT.     

抗凝与非抗凝血标本对ELISA检测血清乙肝表面抗原的影响

目的 探讨抗凝与非抗凝血液标本对乙肝表面抗原酶联免疫吸附试验(ELASA)检测结果是否存在差别.方法 留取160人份血标本各2管,分别经枸橼酸-枸橼酸钠抗凝及非抗凝,进行平行实验.结果 160人份标本的平行试验,部分项目结果差异有统计学意义(P＜0.05).结论 采用枸橼酸-枸橼酸钠抗凝血标本,对乙肝表面抗原检测结果存在着一定干扰,采用抗凝血标本进行ELASA检测对试验结果是否有影响已被同行广泛关注.     

急性心肌梗死合并左心室附壁血栓患者经皮冠状动脉介入术后的抗栓治疗

目的分析急性心肌梗死（AMI）并发左心室附壁血栓（LvT）行经皮冠脉介入治疗（PCI）患者的临床特征及抗栓治疗。方法收集煤炭总医院2005年8月至2012年2月确诊为急性心肌梗死并发左室附壁血栓并行PCI治疗的12例患者的临床资料,对其进行回顾性分析。结果广泛前壁心肌梗死、前壁心肌梗死9例（75％）,左室射血分数低于40％共7例（58％）,冠脉造影检查三支及以上血管病变7例（58％）。6例给予华法林、阿司匹林、氯吡格雷三联抗栓,2例给予西洛他唑、阿司匹林及氯吡格雷三联抗血小板治疗,随访期间血栓均消失。4例双联抗血小板治疗者l例发生脑梗死后加用华法林,3例患者血栓消失,1例血栓机化。12例患者均未出现严重出血现象。结论急性心肌梗死并发左心室附壁血栓并接受PCI治疗患者,充分衡量获益及出血风险,按照个体化原则给予抗栓治疗安全有效。     

POSSIBLE STRATEGIES TO PROLONG CIRCUIT LIFE DURING HEMOFILTRATION: THREE CONTROLLED STUDIES

Background and Aims: The prevention of filter clotting is an important goal in the management of continuous renal replacement therapy (CRRT). Anticoagulation is the mainstay of such prevention. However, other strategies might prolong filter life without increasing the risk of bleeding. We tested the effectiveness of three strategies (use of flat plate configuration, heparin administration into the air chamber and use of a larger membrane surface) aimed at prolonging circuit life without increasing the dose of anticoagulation. Methods: Thirty-one critically ill patients with acute renal failure (ARF) managed with continuous venovenous hemofiltration (CVVH) were studied. Filters were randomized in a crossover design to three consecutive studies: (1) filtration with either hollow-fiber or flat-plate hemofilters, (2) administration of heparin dose pre-filter or divided into pre-filter and directly into the bubble trap chamber and (3) use of two different surface areas with Filtral 8 (surface area 0.75 m²) vs. Filtral 12 (surface area 1.30 m²) hemofilters. Results: Mean circuit life for flat-plate and hollow-fiber hemofilters (cohort 1) was 14.7 ± 4.7 h and 17.1 ± 2.8 h respectively (NS). Mean circuit life for single heparin administration site vs. double site administration (cohort 2) was 17 ± 3.2 h and 18 ± 3.1 h respectively (NS). Mean circuit lifespan for 0.75 m² and 1.30 m² hemofilters was 16 ± 12.2 h and 15.7 ± 14.3 h respectively (NS) (cohort 3). Visible clot formation in the bubble trap chamber was a frequent cause of circuit failure. Conclusion: Neither flat plate membrane configuration nor increasing membrane surface area, nor heparin administration in the air chamber prolong circuit life during CVVH. The bubble trap chamber is a frequent site of circuit clotting.