The role of low-molecular-weight heparins as supportive care therapy in cancer-associated thrombosis

Disulfide Cross-Linked Polymeric Redox-Responsive Nanocarrier Based on Heparin, Chitosan and Lipoic Acid Improved Drug Accumulation, Increased Cytotoxicity and Selectivity to Leukemia Cells by Tumor Targeting via "Aikido" Principle

We have developed a micellar formulation of anticancer drugs based on chitosan and heparin grafted with lipoic and oleic acids that can release the cytotoxic cargo (doxorubicin) in response to external stimuli, such as increased glutathione concentration-a hallmark of cancer. Natural polysaccharides (heparin and chitosan) provide the pH sensitivity of the nanocarrier: the release of doxorubicin (Dox) is enhanced in a slightly acidic environment (tumor microenvironment). Fatty acid residues are necessary for the formation of nanoparticles (micelles) and solubilization of cytostatics in a hydrophobic core. Lipoic acid residues provide the formation of a labile S-S cross-linking between polymer chains (the first variant) or covalently attached doxorubicin molecules through glutathione-sensitive S-S bridges (the second variant)-both determine Redox sensitivity of the anticancer drugs carriers stable in blood circulation and disintegrate after intracellular uptake in the tumor cells. The release of doxorubicin from micelles occurs slowly (20%/6 h) in an environment with a pH of 7.4 and the absence of glutathione, while in a slightly acidic environment and in the presence of 10 mM glutathione, the rate increases up to 6 times, with an increase in the effective concentration up to 5 times after 7 h. The permeability of doxorubicin in micellar formulations (covalent S-S cross-linked and not) into Raji, K562, and A875 cancer cells was studied using FTIR, fluorescence spectroscopy and confocal laser scanning microscopy (CLSM). We have shown dramatically improved accumulation, decreased efflux, and increased cytotoxicity compared to doxorubicin control with three tumor cell lines: Raji, K562, and A875. At the same time, cytotoxicity and permeability for non-tumor cells (HEK293T) are significantly lower, increasing the selectivity index against tumor cells by several times.

Discharge or admit? Emergency department management of incidental pulmonary embolism in patients with cancer: a retrospective study

BACKGROUND

Hospitalization and early anticoagulation therapy remain standard care for patients who present to the emergency department (ED) with pulmonary embolism (PE). For PEs discovered incidentally, however, optimal therapeutic strategies are less clear-and all the more so when the patient has cancer, which is associated with a hypercoagulable state that exacerbates the threat of PE.

METHODS

We conducted a retrospective review of a historical cohort of patients with cancer and incidental PE who were referred for assessment to the ED in an institution whose standard of care is outpatient treatment of selected patients and use of low-molecular-weight heparin for anticoagulation. Eligible patients had received a diagnosis of incidental PE upon routine contrast enhanced chest CT for cancer staging. Survival data was collected at 30 days and 90 days from the date of ED presentation and at the end of the study.

RESULTS

We identified 193 patients, 135 (70%) of whom were discharged and 58 (30%) of whom were admitted to the hospital. The 30-day survival rate was 92% overall, 99% for the discharged patients and 76% for admitted patients. Almost all (189 patients, 98%) commenced anticoagulation therapy in the ED; 170 (90%) of these received low-molecular-weight heparin. Patients with saddle pulmonary artery incidental PEs were more likely to die within 30 days (43%) than were those with main or lobar (11%), segmental (6%), or subsegmental (5%) incidental PEs. In multivariate analysis, Charlson comorbidity index (age unadjusted), hypoxemia, and incidental PE location (P = 0.004, relative risk 33.5 (95% CI 3.1-357.4, comparing saddle versus subsegmental PE) were significantly associated with 30-day survival. Age, comorbidity, race, cancer stage, tachycardia, hypoxemia, and incidental PE location were significantly associated with hospital admission.

CONCLUSIONS

Selected cancer patients presenting to the ED with incidental PE can be treated with low-molecular-weight heparin anticoagulation and safely discharged. Avoidance of unnecessary hospitalization may decrease in-hospital infections and death, reduce healthcare costs, and improve patient quality of life. Because the natural history and optimal management of this condition is not well described, information supporting the creation of straightforward evidence-based practice guidelines for ED teams treating this specialized patient population is needed.

Prevalence of deep vein thrombosis in acutely admitted ambulatory non-surgical intensive care unit patients

Background

Data on prevalence rates of venous thromboembolism (VTE) in different patient populations are scarce. Most studies on this topic focus on older patients or patients with malignancies, immobilization or thrombophilia. Less is known about the VTE risk profile of non-surgical patients presenting with a variety of medical diseases of differing severity. Aim of the present study was to investigate VTE prevalence in a pospective cohort study of ambulatory medical intensive care unit patients within 24 h after acute admission.

Methods

Prospective cohort study of 102 consecutive patients after acute admission to medical intensive care unit. Ultrasound compression sonography, APACHE-II-Scoring and laboratory examination was performed within 24 hours after admission.Possible determinants of a high risk of VTE were examined. In all patients with a confirmed diagnosis of DVT or suspicion of PE thoracic computer tomography (CT) was performed.

Results

VTE was found in 7.8% out of 102 of patients, mean APACHE-II-Score was 14 (mortality risk of about 15%). Thrombus location was femoropopliteal in 5 patients, iliacal in 2 and peroneal in 1 patient. Five VTE patients had concomitant PE (62.5% of VTE, 4.9% of all patients). No predictors of prevalent VTE were identified from univariable regression analysis although relative risk was high in patients with a history of smoking (RR 3.40), immobility (RR 2.50), and elevated D-Dimer levels (RR 3.49).

Conclusions

Prevalent VTE and concomitant PE were frequent in acutely admitted ICU patients.

Endovascular electrocardiography to guide placement of totally implantable central venous catheters in oncologic patients

PURPOSE

Appropriate tip position of totally implantable central venous catheters is essential in order to prevent catheter-related complications, in particular thrombosis. Endovascular electrocardiography is an economic and safe method to guide placement of catheters into the central veins. Although widely utilized, there is still lack of conclusive evidence about its efficacy. The aim of the study was to assess the efficacy and safety of endovascular electrocardiographic guided placement compared to the anthropometric method.

METHODS

Endovascular ECG was employed to guide electrocardiographic placement of a central venous catheter in a cohort of oncologic patients. The rate of correct placement and the incidence of catheter-related thrombosis were considered. Patients in which central venous catheters were inserted with the anthropometric technique were considered as control group.

RESULTS

The rate of correct placement was 91% and 50% for ECG-guided and anthropometric catheters (p<0.0001) respectively. None of the patients suffered from early insertion-related complications. The rate of catheter-related vascular thrombosis was lower for ECG-guided catheters (3.6% vs. 9.6%, n.s.), in particular for left-inserted catheters (0% vs. 33.3%, p=0.02).

CONCLUSION

Endovascular electrocardiography was more effective than the anthropometric technique in placement of implantable central venous catheters and was associated with a lower incidence of catheter-related thrombosis, in particular for those inserted from the left-side.