The Erythrosense as a Real-Time Biomarker to Reveal the Presence of Enhanced Red Blood Cell Aggregability in Atherothrombosis

Unfractionated Heparin TID Dosing Regimen Is Associated With a Lower Rate of Pulmonary Embolism When Compared With BID Dosing in Patients Undergoing Craniotomy

BACKGROUND

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), and intracranial hemorrhage (ICH) may complicate the post-operative course of patients undergoing craniotomy. While prophylaxis with unfractionated heparin (UFH) has been shown to reduce VTE rates, twice-daily (BID) and three-times-daily (TID) UFH dosing regimens have not been compared in neurosurgical procedures. The objective of this study was to explore the association between UFH dosing regimen and rates of VTE and ICH in craniotomy patients.

METHODS

A retrospective chart review was conducted for 159 patients at Northwestern University receiving 5000 units/0.5 mL UFH injections either BID (n = 132) or TID (n = 27). General linear regression models were run to predict rates of DVT, PE, and reoperation due to bleeding from UFH dosing regimen while controlling for age at surgery, sex, VTE history, craniotomy for tumor resection, surgery duration, length of stay, reoperation, infections, and IDH/MGMT mutations.

RESULTS

Receiving UFH TID was significantly associated with a lower rate of PE when compared with receiving UFH BID (β = -0.121, P = 0.044; TID rate = 0%, BID rate = 10.6%). UFH TID also showed a trend toward lower rates of DVT (β = -0.0893, P = 0.295; TID rate = 18.5%, BID rate = 21.2%) when compared with UFH BID. UFH TID showed no significant difference in rate of reoperation for bleeding when compared to UFH BID (β = -0.00623, P = 0.725; TID rate = 0%, BID rate = 0.8%).

CONCLUSIONS

UFH TID dosing is associated with lower rates of PE when compared with BID dosing in patients undergoing craniotomy.

Individual patient data meta-analysis of enoxaparin vs. unfractionated heparin for venous thromboembolism prevention in medical patients

BACKGROUND

Unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) are both recommended for venous thromboembolism (VTE) prophylaxis in hospitalized medical patients.

OBJECTIVE

To perform an individual patient data meta-analysis to evaluate the relative efficacy and safety of the LMWH enoxaparin and UFH in preventing VTE in hospitalized medical patients.

METHODS

Randomized clinical trials comparing subcutaneous enoxaparin (4000 IU once-daily) and UFH (5000 IU subcutaneous two- or three-times daily) for VTE prevention were identified by a systematic search. Individual patient data were obtained from each eligible trial.

RESULTS

Overall, four trials were eligible, including 3600 patients randomized to receive enoxaparin (n = 1799) or UFH (n = 1801). Median patient age was 71 years, and 49.3% were female. Compared with UFH, enoxaparin was associated with risk reductions of 37% for total VTE [relative risk (RR) 0.63, 95% confidence interval (CI) 0.51-0.77] and 62% for symptomatic VTE (RR 0.38, 95% CI 0.17-0.85) at day 15. RR for total VTE in stroke and non-stroke patients was 0.59 (95% CI 0.47-0.74) and 0.87 (95% CI 0.51-1.50), respectively. Major bleeding rates were consistently low and similar between treatment groups at day 15 (RR 1.13, 95% CI 0.53-2.44). There was a trend towards reduced risk for mortality in patients receiving enoxaparin (RR 0.83, 95% CI 0.64-1.08), compared with UFH.

CONCLUSIONS

Enoxaparin significantly reduces VTE in hospitalized medical patients, compared with UFH, without increasing the risk for major bleeding, and was associated with a trend towards reduced all-cause mortality.

Choosing the right heparin prophylaxis strategy in medical patients at risk for developing VTE: an evidence-based approach

Many acutely ill medical patients are at significant risk for developing venous thromboembolism (VTE) during hospitalization. Venous thromboembolism risk arises from both the presenting clinical condition as well as predisposing risk factors, such as advanced age. Thromboprophylaxis is underprescribed in these patients. Thrombotic risk assessment could encourage the prescribing of thromboprophylaxis and, therefore, improve patient protection against VTE. Current guidelines from the American College of Chest Physicians and the International Union of Angiology (IUA) recommend thromboprophylaxis with low-dose unfractionated heparin (UFH), a low-molecular-weight heparin (LMWH), or fondaparinux for acutely ill medical patients with VTE risk factors. However, the optimal dose regimen for UFH is unclear. The 2006 evidence-based guidelines from the IUA recommend a 3-times-daily dose regimen for UFH. However, UFH is usually administered twice daily despite a lack of evidence for the superiority of this regimen. Both heparin-induced thrombocytopenia and bleeding are associated with UFH, and to a lesser degree with alternative anticoagulants, such as the LMWHs. If utilized, an appropriate prophylaxis regimen in medical patients can reduce the risk of VTE and its burden.

Venous thromboembolism prophylaxis with unfractionated heparin in the hospitalized medical patient: the case for thrice daily over twice daily dosing

For venous thromboembolism (VTE) prevention in the hospitalized medical patient, no head-to-head trials have been performed of unfractionated heparin (UFH) 5,000 U subcutaneously thrice (i.e. q8 h or TID) daily versus twice daily (q12 h or BID). Several meta-analyses have been undertaken in attempts to determine whether one regimen may be more beneficial for safety and efficacy. Currently, not all international guidelines include a recommended frequency for UFH. Delineation of this frequency may be helpful to the practicing clinician. Primary studies (with a modified Jadad score of >or=6 to demonstrate a stronger study design) that compared low molecular weight heparin (LMWH) and UFH, and UFH and placebo were evaluated. Meta-analyses evaluating safety and efficacy of LMWH versus UFH, or TID UFH versus BID UFH were also evaluated. Although BID UFH shows some efficacy in one primary study, it is no more beneficial than no prophylaxis in another study. LMWH appears to be more efficacious than BID UFH, but comparable in safety and efficacy to TID UFH. Meta-analytic data demonstrates that BID UFH may have some reduction in deep vein thrombosis. Meta-analytic data also suggests that TID UFH is more efficacious than BID UFH at the cost of more major bleeding. The medical patient with risk factors for the development of VTE appears to be at moderate to high risk. International guidelines for VTE prevention should incorporate a frequency for UFH to guide use. TID UFH is superior in efficacy to BID UFH even when taking into consideration the increased rate of major bleeds. Newly published risk-assessment models may be beneficial in determining which patients would best benefit from BID UFH or TID UFH.

Epidemiology of venous thromboembolism in cardiorespiratory and infectious disease

Venous thromboembolic complications -- deep vein thrombosis and pulmonary embolism -- occur in a significant proportion of hospitalized medical patients. The incidence in acutely ill medical patients is 10%-40%, equivalent to that seen in general surgical patients. Prophylaxis is effective and well tolerated, yet remains under-prescribed in medical wards. Current recommendations for prophylaxis are generalized and do not specifically address many patient groups. Data on the prevalence in patients with chronic obstructive pulmonary disease, heart failure, and infectious diseases are limited. However, studies on large numbers of hospitalized patients with these admission diagnoses have provided important information on incidence, and the efficacy of thromboprophylaxis. This review summarizes current knowledge of the epidemiology of venous thromboembolism in patients with chronic obstructive pulmonary disease, heart failure, and infectious diseases, and highlights the benefits of, and needs for, appropriate prophylaxis in these groups. Increased awareness of the prevalence of thrombosis in the major subgroups of medical inpatients should improve the prescribing of prophylaxis and prevent potentially avoidable and costly complications.

The efficacy and safety of enoxaparin versus unfractionated heparin for the prevention of venous thromboembolism after acute ischaemic stroke (PREVAIL Study): an open-label randomised comparison

BACKGROUND

Venous thromboembolism prophylaxis with low molecular weight heparin or unfractionated heparin is recommended in acute ischaemic stroke, but which regimen provides optimum treatment is uncertain. We aimed to compare the efficacy and safety of enoxaparin with that of unfractionated heparin for patients with stroke.

METHODS

1762 patients with acute ischaemic stroke who were unable to walk unassisted were randomly assigned within 48 h of symptoms to receive either enoxaparin 40 mg subcutaneously once daily or unfractionated heparin 5000 U subcutaneously every 12 h for 10 days (range 6-14). Patients were stratified by National Institutes of Health Stroke Scale (NIHSS) score (severe stroke > or =14, less severe stroke <14). The primary efficacy endpoint was the composite of symptomatic or asymptomatic deep vein thrombosis, symptomatic pulmonary embolism, or fatal pulmonary embolism. Primary safety endpoints were symptomatic intracranial haemorrhage, major extracranial haemorrhage, and all-cause mortality. This study is registered with ClinicalTrials.gov, number NCT00077805.

FINDINGS

In the efficacy population (ie, one or more dose received, presence of deep vein thrombosis or pulmonary embolism, or assessment for venous thromboembolism), enoxaparin (n=666) and unfractionated heparin (669) were given for 10.5 days (SD 3.2). Enoxaparin reduced the risk of venous thromboembolism by 43% compared with unfractionated heparin (68 [10%] vs 121 [18%]; relative risk 0.57, 95% CI 0.44-0.76, p=0.0001; difference -7.9%, -11.6 to -4.2); this reduction was consistent for patients with an NIHSS score of 14 or more (26 [16%] vs 52 [30%]; p=0.0036) or less than 14 (42 [8%] vs 69 [14%]; p=0.0044). The occurrence of any bleeding was similar with enoxaparin (69 [8%]) or unfractionated heparin (71 [8%]; p=0.83). The frequency of the composite of symptomatic intracranial and major extracranial haemorrhage was small and closely similar between groups (enoxaparin 11 [1%] vs unfractionated heparin 6 [1%]; p=0.23). We noted no difference for symptomatic intracranial haemorrhage between groups (4 [1%] vs 6 [1%], respectively; p=0.55); the rate of major extracranial bleeding was higher with enoxaparin than with unfractionated heparin (7 [1%] vs 0; p=0.015).

INTERPRETATION

Our results suggest that for patients with acute ischaemic stroke, enoxaparin is preferable to unfractionated heparin for venous thromboembolism prophylaxis in view of its better clinical benefits to risk ratio and convenience of once daily administration.

An update on prevention of venous thromboembolism in hospitalized acutely ill medical patients

Both the recently updated consensus guidelines published by the American College of Chest Physicians, and the International Union of Angiology recommend thromboprophylaxis with either low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) in medical patients at risk of VTE. However, no guidance is given regarding the appropriate dosing regimens that should be used for thromboprophylaxis in this patient group. LMWH (enoxaparin and dalteparin) and UFH have been shown to be effective for thromboprophylaxis in at-risk hospitalized medical patients. Although LMWH once daily (o.d.) has been shown to be as effective as UFH three times daily (t.i.d.) for thromboprophylaxis in at-risk medical patients, there are no data to show that UFH twice daily (b.i.d) is as effective as either LMWH o.d. or UFH t.i.d. On the basis of currently available evidence, the LMWHs enoxaparin and dalteparin are more attractive alternatives to UFH for the prevention of VTE in hospitalized medical patients because of their convenient once-daily administration and better safety profile, demonstrated in terms of reduced bleeding, HIT, and other adverse events.