Low-molecular-weight heparin for the prevention of postoperative venous thromboembolism after abdominal surgery: a review

Comparison of efficacy of nadroparin and fondaparinux sodium for prevention of deep vein thromboembolism in lower extremities after total hip arthroplasty and total knee arthroplasty: a retrospective study of 592 patients

OBJECTIVES

To compare the efficacy of nadroparin and fondaparinux sodium for prevention of deep vein thromboembolism (DVT) in lower extremities after total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

A total of 592 patients were enrolled in the study. Clinical data of patients who underwent total hip arthroplasty (THA) and total knee arthroplasty (TKA) in our hospital from December 2021 to September 2022 were retrospectively collected, which mainly included patients' general information, surgery-related information, and DVT-related information. The patients were categorized into the nadroparin group(n = 278) and the fondaparinux sodium group(n = 314) according to the types of anticoagulants used. Anticoagulant therapy began 12-24 h after operation and continued until discharge. DVT prevalence between two groups was compared. The Statistical Package for Social Sciences (SPSS) software version 25 (SPSS, Armonk, NY, USA) was used for statistical analysis.

RESULTS

The prevalence of DVT in the nadroparin group and the fondaparinux sodium group was 8.3% (23/278) and 15.0% (47/314), respectively(p = 0.012). Statistical analysis showed that nadroparin group showed a lower prevalence of thrombosis than fondaparinux group (OR = 1.952, P = 0.012). Subgroup analyses showed that nadroparin group had a lower prevalence of DVT than fondaparinux group in some special patients groups such as female patients (OR = 2.258, P = 0.007), patients who are 65-79 years old (OR = 2.796, P = 0.004), patients with hypertension (OR = 2.237, P = 0.042), patients who underwent TKA (OR = 2.091, P = 0.011), and patients who underwent combined spinal-epidural anesthesia (OR = 2.490, P = 0.003) (P < 0.05).

CONCLUSION

Nadroparin may have an advantage over fondaparinux sodium in preventing DVT in lower extremities after THA and TKA.

Prevention and treatment of thrombosis in cancer and oncohematological patients

The purpose of the review is to highlight the current possibilities for the prevention and treatment of venous thrombotic complications in patients with cancer.

The data of 52 scientific sources published in the Russian and foreign press in 1997–2020 are considered.

Cancer patients are at high risk of thrombotic complications, which worsen the outcome of anticancer treatment and are one of the leading causes of death. Thrombosis in an oncological patient increases the risk of death by 30 times, which is associated with fatal thromboembolism and a more aggressive course of the disease. The leading role in the pathogenesis of thrombotic complications is played by disorders in the hemostasis system caused both by the tumor itself and by therapy. Low molecular weight heparins are considered the basis for specific prophylaxis of thromboembolic complications in cancer patients. The use of low molecular weight heparins after surgery and during chemotherapy effectively reduces the incidence of venous thrombosis. Direct oral anticoagulants are promising drugs for oral administration and are indicated as one of the treatment options for patients with tumor-associated thrombosis with a low risk of bleeding and no drug interactions with ongoing systemic chemotherapy.

An overview of coagulation disorders in cancer patients

A diversity of coagulation disorders in cancer patients arise from tumor-specific growth characteristics, neoangiogenesis with impaired endothelial lining, defective myelopoiesis, hypoproteinemia or metastatic lesions growth with organ dysfunction. Recent investigations have found a clinically relevant correlation of coagulation disorders and tumor growth. These prompted new therapeutic strategies focused on growth factors with the aim to control tumor metastasis, particularly if used for the treatment of micrometastatic disease. However, such treatment may lead to the life threatening coagulation imbalance. A coagulation homeostasis may become further impaired after nonsurgical cancer therapy, especially after preoperative irradiation, which produces lesions precipitating both bleeding and thrombosis. Anticancer chemotherapy may affect liver function and decrease the synthesis of both procoagulation and anticoagulation factors. The most of chemotherapeutic protocols affect platelet synthesis, which arises as a principal dose-limiting side effect. It was observed both during combined systemic chemotherapy and local antitumor therapy. Although the side effects produced by chemotherapy are reversible, endothelial lesions may persist for many years after the anticancer treatment. Instead of cancer patients, there's a growing cohort of patients with nonmalignant diseases who use cytostatics in the perioperative period, and are candidates for surgical procedures not related to their malignant disease, i.e. hernia repair. In this patient population a special attention must be paid to the preoperative evaluation of coagulation status and thromboprophylaxis. This overview reminds the most common coagulation disorders in cancer patients in the perioperative period. It emphasizes the need for proper patient monitoring which may facilitate the diagnostics and treatment of cancer-related coagulation disorders in the perioperative setting.

Approaches to risk-stratifying cancer patients for venous thromboembolism

Cancer patients are clearly at increased risk for venous thromboembolism (VTE). However, the risk is not equal for all cancer patients or even in the same patient over the course of the natural history of cancer. VTE prophylaxis has been shown to be beneficial in certain high-risk populations such as post-surgical or hospitalized cancer patients but data in the ambulatory setting are conflicting. A majority of solid tumor patients are currently treated in the ambulatory setting and studying risk factors for VTE and their interaction is essential to identifying a population of ambulatory cancer patients that could benefit from prophylaxis. In this review, we evaluate the literature on risk factors for cancer-associated VTE and discuss data from a large observational study of cancer patients receiving chemotherapy which has revealed novel risk factors for chemotherapy-associated VTE. Finally, we discuss model-based approaches to risk-stratifying cancer patients that incorporate the known multiple risk factors for VTE and can help identify high-risk subgroups in the cancer population.

Pulmonary Embolism Complicating Bariatric Surgery: Detailed Analysis of a Single Institution’s 24-Year Experience

BACKGROUND

Morbidly obese patients undergoing bariatric procedures are at risk for pulmonary embolism (PE). Because large series are required to analyze low-incidence complications, factors predictive of PE have not been clearly defined. Since 1992, short-course heparin prophylaxis, beginning immediately before operation, has been used in this center.

STUDY DESIGN

Prospective data on 3,861 patients undergoing bariatric procedures between 1980 and 2004 were queried. Factors analyzed included age, gender, body mass index, interval between procedure and PE, inpatient versus outpatient status, mortality, access method (open versus laparoscopic), and comorbidities.

RESULTS

PE within 60 days of operation occurred in 33 patients (23 women, 10 men), for an incidence of 0.85%. No difference in incidence was noted between open (0.84%) and laparoscopic (0.88%) groups, nor did routine prophylaxis with heparin since 1992 decrease the incidence. The interval between procedure and PE was 13.2+/-2.6 (mean +/- SEM) days (open=13.0+/-3.0 days, laparoscopic 14.1+/-6.49 days, p=0.9). One-third of PEs occurred after hospital discharge. Pulmonary embolism-related mortality was 27%. A statistically greater body mass index was noted in PE patients compared with non-PE patients (57.2+/-2.4 kg.m(2) versus 49.9+/-0.2 kg/m(2), p < 0.01, Wilcoxon rank test). Multivariate logistic regression confirmed a primary role for preoperative weight as a predictor of PE; univariate analysis suggested an increased PE risk with obesity hypoventilation syndrome, anastomotic leak, and chronic venous insufficiency.

CONCLUSIONS

Data demonstrated persistence of PE risk in the anticoagulation, laparoscopic-access era at a rate similar to that in the preanticoagulation, open-access era. Because one-third of PEs occur after hospital discharge, consideration should be given to continuing anticoagulants longer and to adopting a more aggressive policy of inferior vena cava filter prophylaxis, particularly in patients with high body mass index, obese hyperventilation syndrome, and venous insufficiency.

Inhibition of extrinsic hemostasis activation by low-molecular-weight heparin

Low-molecular-weight heparins (LMWHs) are very important drugs; unfortunately, the routine global hemostasis assays activated partial thromboplastin time and prothrombin time are not sensitive to LMWHs. Here the 50% inhibitory concentration (IC(50)) values of heparin and LMWHs on extrinsic thrombin generation are determined. Pooled normal plasma was supplemented with 0-2 IU/ml unfractionated heparin, 0-2 IU/ml LMWH dalteparin, or 0-20 microg/ml pentosanpolysulfate in 5-ml polystyrole tubes (23 degrees C) and tested in the tissue-factor-triggered extrinsic coagulation activity assay (EXCA): 50 microl plasma + 5 microl tissue factor/CaCl(2), 1 and 2 min incubation time at 37 degrees C (coagulation reaction time for EXCA-1 and EXCA-2); + 100 microl of 2.5 mol/l arginine (pH 8.6), 20 min at room temperature; + 50 microl of 1 mmol/l CHG-Ala-Arg-pNA, 1.25 mol/l arginine; increase in absorbance/time at 23 degrees C; calibrator = 1 IU/ml bovine thrombin in 6.7% human albumin replacing the plasma sample; in EXCA-1, about 1 IU/ml thrombin is generated in pooled unfrozen normal citrated plasma. The IC(50) values in EXCA-1 are 0.1 IU/ml heparin, 0.02 IU/ml LMWH, and 4.7 microg/ml pentosanpolysulfate. In ECXA-2 the IC(50) values are 0.07 IU/ml, 0.01 IU/ml, and 4.6 microg/ml, respectively. The EXCA reflects the efficiency of anticoagulants on plasmatic coagulation. It is suggested to adjust the dosage of LMWH according to the EXCA value; about 30% of normal extrinsic thrombin generation might be the correct dose for prophylactic anticoagulation.