Low molecular weight heparins versus unfractionated heparin for acute coronary syndromes

WITHDRAWN: Puerarin injection for unstable angina pectoris

The Editor/CRG withdrew this review as the current author team is unable to progress to the final stage of the review update. The editors consider this title as low priority for the current portfolio of the Heart Group and therefore this title is not open to a new author team.

The editorial group responsible for this previously published document have withdrawn it from publication.

Heparin versus placebo for non-ST elevation acute coronary syndromes

BACKGROUND

Non-ST elevation acute coronary syndromes (NSTEACS) represent a spectrum of disease including unstable angina and non-ST segment myocardial infarction (NSTEMI). Despite treatment with aspirin, beta-blockers and nitroglycerin, unstable angina/NSTEMI is still associated with significant morbidity and mortality. Although evidence suggests that low molecular weight heparin (LMWH) is more efficacious compared to unfractionated heparin (UFH), there is limited data to support the role of heparins as a drug class in the treatment of NSTEACS. This is an update of a review last published in 2008.

OBJECTIVES

To determine the effect of heparins (UFH and LMWH) compared with placebo for the treatment of patients with non-ST elevation acute coronary syndromes (unstable angina or NSTEMI).

SEARCH METHODS

For this update the Cochrane Heart Group Trials Search Co-ordinator searched the Cochrane Central Register of Controlled Trials on The Cochrane Library (2013, Issue 12), MEDLINE (OVID, 1946 to January week 1 2014), EMBASE (OVID, 1947 to 2014 week 02), CINAHL (1937 to 15 January 2014) and LILACS (1982 to 15 January 2014). We applied no language restrictions.

SELECTION CRITERIA

Randomized controlled trials of parenteral UFH or LMWH versus placebo in people with non-ST elevation acute coronary syndromes (unstable angina or NSTEMI).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed quality of studies and independently extracted data.

MAIN RESULTS

There were no new included studies for this update. Eight studies (3118 participants) were included in this review. We found no evidence for difference in overall mortality between the groups treated with heparin and placebo (risk ratio (RR) = 0.84, 95% confidence interval (CI) 0.36 to 1.98). Heparins compared with placebo, reduced the occurrence of myocardial infarction in patients with unstable angina and NSTEMI (RR = 0.40, 95% CI 0.25 to 0.63, number needed to benefit (NNTB) = 33). There was a trend towards more major bleeds in the heparin studies compared to control studies (RR = 2.05, 95% CI 0.91 to 4.60). From a limited data set, there appeared to be no difference between patients treated with heparins compared to control in the occurrence of thrombocytopenia (RR = 0.20, 95% CI 0.01 to 4.24). Assessment of overall risk of bias in these studies was limited as most of the studies did not give sufficient detail to allow assessment of potential risk of bias.

AUTHORS' CONCLUSIONS

Compared with placebo, patients treated with heparins had a similar risk of mortality, revascularization, recurrent angina, and thrombocytopenia. However, those treated with heparins had a decreased risk of myocardial infarction and a higher incidence of minor bleeding. Overall, the evidence assessed in this review was classified as low quality according to the GRADE approach. The results presented in this review must therefore be interpreted with caution.

Dosing practice of low molecular weight heparins and its efficacy and safety in cardiovascular inpatients: a retrospective study in a Chinese teaching hospital

Background

Low-molecular-weight heparins (LMWHs) are safe and effective anticoagulant options for cardiovascular patients when applied as body weight-adjusted doses. However, there are some barriers that make it difficult to implement weight-adjusted doses in clinical practice. Therefore, it is vital to learn the dosing practices of LMWH and its efficacy and safety in clinical practice.

Methods

A retrospective study was conducted in cardiovascular inpatients who had received at least one dose of LMWH during a 6-month period. Appropriateness of LMWH dosing was determined and major clinical outcomes (major adverse vascular events and major bleeding) during hospitalization were evaluated.

Results

A total of 376 admissions representing 364 patients received LMWH treatment. Of these, 17.0% (64/376) of admissions did not have body weight records. Of the 312 admissions included for the outcome study, only 34 cases (10.9%) received the recommended doses of LMWH, while 51 cases (16.3%) received mild underdoses, 223 cases (71.5%) received major underdoses and 4 (1.3%) received excess doses. There were 10 major adverse vascular events, which occurred more often in patients receiving excess doses of LMWH than in patients receiving recommended, mild or major underdoses (50%, 2.9%, 2.0% and 2.7%, respectively, P < 0.001). After multivariable analysis, severe renal insufficiency was an independent risk factor for major adverse vascular events [odds ratio (OR), 31.93; 95% confidence interval (CI), 5.99-170.30; P < 0.001]. No major bleeding was recorded.

Conclusions

Underdose of LMWH is commonly used in cardiovascular inpatients, which was suboptimal according to guidelines. Using LMWH at a fixed, low dose for treatment purposes in patients without severe renal insufficiency was not associated with a higher risk of adverse vascular events in the current study, though larger studies with extended follow-ups are required to fully assess the long-term consequences of LMWH underdosing.

Bleeding risk during treatment of acute thrombotic events with subcutaneous LMWH compared to intravenous unfractionated heparin; a systematic review

BACKGROUND

Low Molecular Weight Heparins (LMWH) are at least as effective antithrombotic drugs as Unfractionated Heparin (UFH). However, it is still unclear whether the safety profiles of LMWH and UFH differ. We performed a systematic review to compare the bleeding risk of fixed dose subcutaneous LMWH and adjusted dose UFH for treatment of venous thromboembolism (VTE) or acute coronary syndromes (ACS). Major bleeding was the primary end point.

METHODS

Electronic databases (MEDLINE, EMBASE, and the Cochrane Library) were searched up to May 2010 with no language restrictions. Randomized controlled trials in which subcutaneous LMWH were compared to intravenous UFH for the treatment of acute thrombotic events were selected. Two reviewers independently screened studies and extracted data on study design, study quality, incidence of major bleeding, patients' characteristics, type, dose and number of daily administrations of LMWH, co-treatments, study end points and efficacy outcome. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using the random effects model.

RESULTS

Twenty-seven studies were included. A total of 14,002 patients received UFH and 14,635 patients LMWH. Overall, no difference in major bleeding was observed between LMWH patients and UFH (OR = 0.79, 95% CI 0.60-1.04). In patients with VTE LMWH appeared safer than UFH, (OR = 0.68, 95% CI 0.47-1.00).

CONCLUSION

The results of our systematic review suggest that the use of LMWH in the treatment of VTE might be associated with a reduction in major bleeding compared with UFH. The choice of which heparin to use to minimize bleeding risk must be based on the single patient, taking into account the bleeding profile of different heparins in different settings.

Consequences of major bleeding in hospitalized patients with non-ST segment elevation acute coronary syndromes receiving injectable anticoagulants

OBJECTIVE

To evaluate the burden of major bleed in patients with non-ST segment elevation acute coronary syndromes (NSTE ACS) receiving injectable anticoagulation from the hospital perspective.

METHODS

Retrospective analysis of inpatient medical and pharmacy data from the Premier Perspective Comparative Database between 1/1/2003 and 3/31/2006. Hospitalized patients aged >or=18 years with a diagnosis of UA or NSTEMI who received an injectable anticoagulant agent during the same hospital stay were stratified into two cohorts: those who experienced a major bleed during hospitalization and those who did not, defined by the presence of >or=1 pre-specified ICD-9 codes. Length of hospital stay (LOS), inpatient mortality, 30-day readmissions, and hospitalization costs over 30 days were assessed between the cohorts using statistical models to control for covariates which may have impacted the outcomes.

RESULTS

Patients with a major bleed had significantly longer length of stay (13.8 days vs 5.6 days), higher readmission rates (31.3% vs 14.7%), and increased all-cause mortality (15.0% vs 4.5%) compared with patients who did not bleed. After controlling for covariates, major bleeding was significantly associated with increased length of stay, readmission rate, and mortality. Adjusted costs were $13,856 higher on average for patients with a major bleed (95% CI: $13,828-$18,884; p < 0.0001). Subanalyses conducted on patients aged >or=65 years and those undergoing invasive procedures demonstrated higher occurrence of bleed than the general population and a similar impact on outcomes assessed.

CONCLUSION

In conclusion, the study showed that patients with UA or NSTEMI who experience a major bleed have significantly longer hospital stays, higher readmission rates, increased costs, and increased mortality than those without a major bleed. These data emphasize the importance of considering the safety profile in context of the efficacy of the recommended agents. The findings from this study are limited by the retrospective study design and certain endpoints, such as readmissions, may have been underreported.

Heparin versus placebo for acute coronary syndromes

BACKGROUND

Acute coronary syndromes (ACS) represent a spectrum of disease including unstable angina (UA) and non-ST segment myocardial infarction (NSTEMI). Despite treatment with aspirin, beta-blockers and nitroglycerin, UA/NSTEMI is still associated with significant morbidity and mortality. Although emerging evidence suggests that low molecular weight heparin (LMWH) is more efficacious compared to unfractionated heparin (UFH), there is limited data to support the role of heparins as a drug class in the treatment of ACS.

OBJECTIVES

To determine the effect of heparins (UFH and LMWH) compared with placebo for the treatment of patients with ACS.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials on The Cochrane Library (issue 4, 2002), MEDLINE (1966 to May 2002), EMBASE (1980 to May 2002) and CINAHL (1982 to May 2002). Authors of included studies and pharmaceutical industry representatives were contacted to determine if unpublished studies which met the inclusion criteria were available.

SELECTION CRITERIA

Randomized controlled trials of parenteral UFH or LMWH versus placebo in people with ACS (UA or NSTEMI).

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed quality of studies. Data were extracted independently by two reviewers. Study authors were contacted to verify and clarify missing data.

MAIN RESULTS

Eight studies (3118 participants) were included in this review. We found no evidence for difference in overall mortality between the groups treated with heparin and placebo (RR = 0.84, 95% CI 0.36 to 1.98). Heparins reduced the occurrence of MI (RR = 0.40, 95% CI 0.25 to 0.63, NNT = 33). An increase in the incidence of minor bleeds (RR = 6.80, 95% CI 1.23 to 37.49, NNH = 17).

AUTHORS' CONCLUSIONS

Compared to placebo, patients treated with heparins had similar risk of mortality, revascularization, recurrent angina, major bleeding and thrombocytopenia. However, those treated with heparins had decreased risk of MI and a higher incidence of minor bleeding.

Puerarin injection for unstable angina pectoris

BACKGROUND

Puerarin is extracted from the Chinese herb puerariae lobata. Many users of Chinese herbal medicine believe that puerarin has positive effects in the treatment of coronary heart disease (CHD). In recent years puerarin injection has been widely used to treat CHD and angina pectoris.

OBJECTIVES

To assess the benefits and harms of puerarin injection for unstable angina.

SEARCH STRATEGY

The following electronic databases were searched: The Cochrane Controlled Trials Register on The Cochrane Library (Issue 3, 2004), MEDLINE (1995 to 2004), EMBASE (1995 to 2004), CBM (1995 to 2004), Chinese Cochrane Centre Controlled Trials Register (to 2004), Current Controlled Trials (www.controlled-trials.com) and The National Research Register. We also hand searched 60 Chinese traditional medicine journals.

SELECTION CRITERIA

Randomised controlled trials undertaken on adults with unstable angina evaluating the following types of interventions: Puerarin injection compared to western drugs or placebo, or puerarin injection used with western drugs compared to western drugs alone.

DATA COLLECTION AND ANALYSIS

Data were extracted and analysed independently by two reviewers. Differences in data extraction and analysis were resolved by consensus, referring back to the original article. Study authors were contacted for additional information. Adverse effects information was collected from the trials.

MAIN RESULTS

20 trials involving 1240 people were included. All trials identified were classified as having a high risk of bias because of poor reported methodology. The duration of treatment was 7-20 days and no information supplied suggested longer follow-ups were conducted for any trials. This limited the observation to participants who were not undertaking normal activities of daily living. The primary outcome (death) was not report in any trial. For all the secondary outcome measures, frequency of acute angina attacks, improvements in ECG, doses and incidence of nitroglycerine needed and levels of plasma endothelin, there was no evidence that puerarin had better or worse effects to other conventional treatments. There was strong evidence to suggest that puerarin injection plus western drugs was a better treatment option than western drugs alone.

AUTHORS' CONCLUSIONS

Puerarin injection may be effective in unstable angina when used in addition to conventional treatments. However, these finding should be interpreted with care because of the very low methodological quality of studies and potential publication bias. In the light of the findings, a more rigorously designed, randomised double-blind placebo-controlled trial is needed.

Low molecular weight heparin and atherosclerosis

Low molecular weight heparin (LMWH) has dramatically impacted the treatment of venous thromboembolic disease and acute coronary syndromes. Recent studies help define the role of these agents for patients undergoing percutaneous coronary interventions and for patients treated with thrombolytic agents for ST-segment elevation myocardial infarction. Recent studies also suggest potential usefulness of LMWH for patients with peripheral vascular disease and its limits of utility in stroke. This review summarizes the evidence about the use of LMWH in these clinical situations.