Statin use and the prevention of venous thromboembolism: a meta-analysis

Epidemiology and prevention of venous thromboembolism

Venous thromboembolism, that consists of the interrelated conditions deep-vein thrombosis and pulmonary embolism, is an under-appreciated vascular disease. In Western regions, approximately 1 in 12 individuals will be diagnosed with venous thromboembolism in their lifetime. Rates of venous thromboembolism are lower in Asia, but data from other regions are sparse. Numerous risk factors for venous thromboembolism have been identified, which can be classified as acute or subacute triggers (provoking factors that increase the risk of venous thromboembolism) and basal or acquired risk factors (which can be modifiable or static). Approximately 20% of individuals who have a venous thromboembolism event die within 1 year (although often from the provoking condition), and complications are common among survivors. Fortunately, opportunities exist for primordial prevention (prevention of the development of underlying risk factors), primary prevention (management of risk factors among individuals at high risk of the condition) and secondary prevention (prevention of recurrent events) of venous thromboembolism. In this Review, we describe the epidemiology of venous thromboembolism, including the incidence, risk factors, outcomes and opportunities for prevention. Meaningful health disparities exist in both the incidence and outcomes of venous thromboembolism. We also discuss these disparities as well as opportunities to reduce them.

Rivaroxaban and Risk of Venous Thromboembolism in Patients With Symptomatic Peripheral Artery Disease After Lower Extremity Revascularization

IMPORTANCE

Prior studies have observed an association between the burden of atherosclerotic vascular disease and the risk of venous thromboembolism (VTE). The association is not well described in peripheral artery disease (PAD) after lower extremity revascularization (LER).

OBJECTIVE

To describe the risk of, factors associated with, and outcomes after VTE, as well as the association of low-dose rivaroxaban plus antiplatelet therapy with VTE after LER.

DESIGN, SETTING, AND PARTICIPANTS

This global, multicenter cohort study used data from the Vascular Outcomes Study of ASA (acetylsalicylic acid) Along With Rivaroxaban in Endovascular or Surgical Limb Revascularization for PAD (VOYAGER PAD) randomized clinical trial, which enrolled patients from 2015 to 2018 with median follow-up of 28 months. Participants included patients with PAD undergoing LER. Patients with an indication for therapeutic anticoagulation were excluded. Data were analyzed from September 2020 to September 2021.

EXPOSURE

Randomization to rivaroxaban 2.5 mg twice daily or placebo on a background of aspirin 100 mg daily; short-term clopidogrel was used at the discretion of the treating physician.

MAIN OUTCOMES AND MEASURES

Symptomatic VTE was a prespecified secondary outcome and prospectively collected.

RESULTS

Among 6564 patients (median [IQR] age, 67 [61-73] years; 4860 [74.0%] men), 66 patients had at least 1 VTE. The 3-year rate of VTE in patients receiving placebo was 1.7%, and the pattern of risk was linear (year 1: 0.5%; year 2: 1.1%). After multivariable modeling, weight (hazard ratio [HR], 3.04; 95% CI, 1.09-8.43), hypertension (HR, 2.11; 95% CI, 0.91-4.89), prior amputation (HR, 2.07; 95% CI, 0.95-4.53), and older age (HR, 1.81; 95% CI, 1.06-3.11) were associated with increased risk of VTE. VTE was associated with risk of subsequent mortality (HR, 7.22; 95% CI, 4.66-11.19). Compared with aspirin alone, rivaroxaban plus aspirin was associated with lower VTE risk (HR, 0.61; 95% CI, 0.37-0.998; P = .047), with benefit apparent early and sustained over time. This association was not modified by use of clopidogrel at randomization (without clopidogrel: HR, 0.55; 95% CI, 0.29-1.07; with clopidogrel: HR, 0.69; 95% CI, 0.32-1.48; P for interaction = .67).

CONCLUSIONS AND RELEVANCE

In this cohort study, there was continuous risk for VTE after LER in patients with PAD, with greater risk in patients who were older and had obesity and those with more severe PAD, as reflected by prior amputation. Low-dose rivaroxaban plus aspirin was associated with lower VTE risk compared with aspirin alone, with benefits apparent early and continued over time. The spectrum of venous and arterial thrombotic events and overall benefits of more potent antithrombotic strategies for prevention should be considered after LER for PAD.

Effects of statins in primary and secondary prevention for venous thromboembolism events: A meta analysis

OBJECTIVE

The associations between statins use and incidence or recurrence of venous thromboembolism (VTE) are controversial. We aimed to conduct a meta-analysis to reconcile the conflicting results.

METHODS

We searched PubMed, Embase and Cochrane Library for studies published from database inception until May 31, 2021. Cohort studies and Randomized Controlled Trials that reported incidence or recurrence of VTE using statins compared with placebo or non-statins were included for meta-analysis.

RESULTS

A total of 43 studies comprising over 8.6 million participants were included for analysis. The median follow-up duration was 38.1 months. Compared with no statins treatment, statins appeared to have a protective effect in primary prevention of VTE (RR 0.78, 95% CI 0.72-0.85), but significant heterogeneity was found among included studies (I² = 81%). Statins was also associated with a 26% reduced risk of recurrent VTE (RR 0.74, 95% CI 0.70-0.78), even in patients receiving anticoagulant therapy (RR 0.77, 95% CI 0.65-0.92). In patients with a history of VTE, statins was associated with a reduced risk of bleeding and all cause mortality. The NNT of statins to prevent one case of VTE in the cancer population, and one case of recurrent VTE in patients with a history of VTE was 103.1 and 90.7 person-years respectively.

CONCLUSION

In high-risk patients, statins treatment may reduce the incidence of VTE. Statins can also reduce the risk of recurrent VTE and all-cause mortality in patients with a history of VTE.

Statin Therapy and the Incidence of Thromboembolism and Vascular Events Following Liver Transplantation

Statin therapy may reduce the risk of venous thromboembolism (VTE), which may impact solid organ transplant outcomes. We evaluated the incidence of VTE and other complications after liver transplantation stratified by hyperlipidemia status and statin use using a retrospective cohort study approach. We reviewed all primary orthotopic liver transplantation (OLT) records from January 2014 to December 2019 from our center. Intraoperative deaths were excluded. Recipient, donor clinical and demographic data were collected. We developed risk-adjusted models to assess the effect of statin use on the occurrence of VTE, hepatic artery complications (HACs), graft failure, and death, accounting for clinical covariates and competing risks. A total of 672 OLT recipients were included in the analysis. Of this cohort, 11.9% (n = 80) received statin therapy. A total of 47 patients (7.0%) had VTE events. HACs occurred in 40 patients (6.0%). A total of 42 (6.1%) patients experienced graft loss, whereas 9.1% (n = 61) of the cohort died during the study interval. Eighty OLT recipients (29.8%) were treated with statins. In the statin treated group, 0% of patients had VTE versus 7.9% of those not on statins (P = 0.02). HACs were identified in 1.2% of the statin group and 6.8% of the nonstatin group. Untreated hyperlipidemia was associated with a 2.1-fold higher risk of HACs versus patients with no hyperlipidemia status (P = 0.05). Statin therapy was associated with significantly better risk-adjusted thromboembolic event-free survival (absence of VTE, cerebrovascular accident, myocardial infarction, HACs, and death); hazard ratio, 2.7; P = 0.01. These data indicate that statin therapy is correlated with a lower rate of VTE and HACs after liver transplantation.

Differential effect of statin use on coagulation markers: an active comparative analysis in the NEO study

Background

Statins are a potential treatment for venous thromboembolism (VTE) prophylaxis complementary to conventional anticoagulants without associated bleeding complications. This study aimed to compare pro-thrombotic activities of different classes of lipid-lowering drugs in an active comparator design and determine whether there is a relation between statin versus fibrate/niacin use and pro-coagulant factor outcomes.

Methods

This is a cross-sectional analysis of participants from the Netherlands Epidemiology of Obesity study using any class of lipid-lowering drugs, including any types of statins, niacin, and fibrates. We performed linear regression analyses to determine fibrinogen, factor (F) VIII, FIX, and FXI activity in statins versus fibrate/niacin users and adjusted for age, sex, tobacco smoking, body mass index (BMI), hypertension, diabetes, and prevalent cardiovascular disease.

Results

Among 1043 participants, the mean age was 58.4 ± 5.2 years, 61% were men, and the mean BMI was 31.3 ± 4.5 kg/m². Clinical characteristics were balanced between statin and fibrate/niacin users. Statin users had lower mean FXI (18.3 IU/dL, 95% confidence interval (CI) 9.4 to 27.3) levels compared to fibrate/niacin users. The level of FVIII (15.8 IU/dL, 95% CI − 0.003 to 31.6), and FIX (11.3 IU/dL, 95% CI − 0.4 to 23.2) were lower in statin users than fibrate/niacin users with marginal statistical significance.

Conclusion

Current statin use was associated with lower plasma levels of FXI than fibrate/niacin use. The effects on coagulation factors may, in part, explain the benefit of statin therapy rendered in primary and secondary prevention of VTE.

COVID-19 and Thromboinflammation: Is There a Role for Statins?

The novel coronavirus disease (COVID-19) showed increased morbidity and mortality rates and worse prognosis in individuals with underlying chronic diseases, especially cardiovascular disease and its risk factors, such as hypertension, diabetes, and obesity. There is also evidence of possible links among COVID-19, myocardial infarction, and stroke. Emerging evidence suggests a pro-inflammatory milieu and hypercoagulable state in patients with this infection. Despite anticoagulation, a large proportion of patients requiring intensive care may develop life-threatening thrombotic complications. Indeed, the levels of some markers of hemostatic activation, such as D-dimer, are commonly elevated in COVID-19, indicating potential risk of deep vein thrombosis and pulmonary thromboembolism. In this review, we critically examine and discuss aspects of hypercoagulability and inflammation in COVID-19 and the possible benefits of statins in this scenario, with emphasis on their underlying molecular mechanisms. Moreover, we present recommendations on the use of antiviral drugs in combination with statins.

Arterial and venous thrombosis: What's the link? A narrative review

Arterial thrombosis and venous thromboembolism (VTE) are traditionally considered two different entities. However, patients with unprovoked VTE are at higher risk of developing subclinical and overt atherosclerosis compared to healthy controls challenging these distinctions. Obesity may explain the association between arterial and venous disease: overweight/obese patients are prone to stasis in lower limbs veins, chronic inflammation, dyslipidemia, hypertension, and diabetes mellitus; all of which result in a hypercoagulability, VTE, and atherosclerosis. Novel therapeutic approaches combining and re-purposing traditional arterial therapies (antiplatelets and statins) and venous thrombosis therapies (anticoagulants) are emerging for the management of patients with vascular disease.

The effect and molecular mechanism of statins on the expression of human anti-coagulation genes

Statins are potent lipid-lowering drugs. Large prospective clinical trials have shown the anti-thrombotic effect of statins, e.g., preventing deep vein thrombosis. However, the mechanism underlying the beneficial effect of statins in reducing thrombus formation remains to be established. We, thus, conduct this study to investigate the potential molecular mechanisms. The cultured human hepatoma cells (HepG2) were used as the in vitro model. The human protein C gene promoter was cloned into the luciferase reporter to study the transcriptional regulation of human protein C gene. Wistar rats fed with simvastatin (5 mg/kg day) were used as the in vivo model. We found that simvastatin increased the expression of protein C in hepatocytes (361 ± 64% and 313 ± 59% after 2 h and 6 h of stimulation, respectively, both p < 0.01). In the animal study, the serum protein C levels were increased in the simvastatin-treated group (7 ± 2.2 unit/ml vs 23.4 ± 19.3 unit/ml and 23.4 ± 18.2 unit/ml and 1 and 2 weeks of treatment, respectively, both p < 0.05). Regarding the possible molecular mechanism, we found that the level of hepatocyte nuclear factor 1α (HNF1α) was also increased in both the in vivo and in vitro models. We found that the protein C promoter activity was increased by simvastatin, and this effect was inhibited by HNF1α knockdown and constitutively active Rac1. Therefore, stains may modulate protein C expression through small GTPase Rac 1 and HNF1α.

The secondary prevention of venous thromboembolism: Towards an individual therapeutic strategy

After the anticoagulant withdrawal, a substantial proportion of patients with venous thromboembolism will develop recurrent events. Whether to consider an extended treatment depends on the risk of recurrence and bleeding risk. The assessment of the individual risk profile remains a difficult task. Several basal and post-basal factors modulate the risk of recurrence and may help clinicians to select patients who can benefit from the extended therapy. During the year 2017, new evidence regarding the post-basal factors was provided by the Morgagni and Scope studies. Another interesting novelty was the VTE-BLEED score, the first bleeding risk score that obtained the external validation in venous thromboembolism setting. In secondary prevention, the use of direct oral anticoagulants is growing instead of vitamin K antagonist. Even at lower doses, direct oral anticoagulants showed to be effective and safe, to reduce all-cause mortality and seemed to be superior to placebo for the composite outcome of fatal bleeding and fatal recurrence. After the recently published Einstein-Choice trial, the role of aspirin has become truly marginal as rivaroxaban 10 mg showed a bleeding risk similar to aspirin 100 mg but a greater effectiveness reducing the relative risk of recurrence by about 70%. Another option for secondary prevention could be sulodexide, with a lower protective effect than direct oral anticoagulants but an interesting safety profile. In conclusion, in our opinion, an individual strategy taking into account the risk of recurrence, bleeding risk, therapeutic options and patient preferences is the most appropriate approach to secondary prevention of venous thromboembolism.

Usefulness of Statins for Prevention of Venous Thromboembolism

Venous thromboembolism (VTE), including deep venous thrombosis and pulmonary embolism, is common with an annual incidence of 1 to 5 per 1,000, resulting in major morbidity, mortality, and increased health care costs. It is more common in the elderly, obese, those with cancer, those undergoing surgery, and those with previous VTE. Strategy to reduce its occurrence has important public health implications. Pleotropic effects of statins may have beneficial effects on a number of potential targets associated with VTE. Statins have excellent safety profile and seem to be associated with beneficial effects in VTE in case-control studies, large observational studies, meta-analyses, and a randomized trial. In conclusion, after critically reviewing the clinical data supporting statin use in the prevention of VTE, we presented clinical recommendations for the use of statins in reducing VTE occurrence, especially in high-risk situations.

Preinjury statin use and thromboembolic events in trauma: a 10-year retrospective evaluation

BACKGROUND

Traumatic injury is well known to increase the risk of venous thromboembolic events (VTEs), occurring in up to 58% of trauma patients. Statin medications have significant anti-inflammatory properties and have been shown to reduce the risk of VTE. We hypothesized that trauma patients who received statin medication before injury would have a lower incidence of VTE after injury.

METHODS

A 10-y retrospective review identified all patients admitted to our trauma service with an injury severity score >9 and an intensive care unit stay of >3 d. This population was categorized as either "statin recipient" (SR) or "statin naïve," with subsequent categorical division by occurrence of VTE. Our primary outcome measure was the occurrence of documented VTE in both statin naïve and SR subjects.

RESULTS

A total of 2519 trauma patients were included with 97 (3.8%) developing VTE. Pretrauma statin use in males remained as an independent predictor of VTE (odds ratio = 2.25, 95% confidence interval = 1.25-4.04, P < 0.01). The median time to VTE onset was 3 d longer in SRs (10.0 d; confidence interval = 7.3-12.7, P < 0.05).

CONCLUSIONS

Pretrauma statin use does not appear to have a protective benefit of VTE prevention in trauma patients, as we have shown pretrauma SR male trauma patients to have a twofold increased incidence of VTE. However, when considering the 3 d longer median time to VTE onset found in SRs, we consider the protective benefit of statin use reported in the current literature as likely attributable to this observed delayed onset.

Role of P-selectin in thromboembolic events in patients with cancer

The objective of the present study was to evaluate the role of P-selectin in patients with cancer with suspected thromboembolic events (TEEs). Patients with cancer have a four times greater risk of developing TEEs. P-selectin is a glycoprotein that has the function of facilitating the interaction (adhesion) of leukocytes with the endothelium, or with platelets. There is a well-defined relationship between P-selectin and thrombosis; however, it is likely that the cut-off value of P-selectin for patients with cancer should be considered differently from that of the general population. In the present report, a prospective cross-sectional study was performed with patients of the Cancer Hospital of Barretos who were suspected of having TEEs. Among the 178 study participants, 167 (93.82%) were suspected of having deep vein thrombosis, while 59 of them (35.33%) were confirmed as such; and 11 (6.18%) were suspected of having pulmonary thromboembolism, while 3 of them were confirmed as such (27.69%). The mean results obtained were: P-selectin, 25.37 ng/ml; and D-dimer, 2,181.22 ng/ml. The P-selectin levels averaged 33.60 ng/ml with the confirmed TEE group compared with 20.40 ng/ml with the unconfirmed TEE group, with a standard deviation of 23.35 compared with 6.92 (P<0.001); and the level of D-dimer was 4,615.38 ng/ml compared with 977.52 ng/ml, with a standard deviation of 6,460.54 compared with 2,145.50 (P<0.001). Multiple logistic regression adjusted for distant metastases and the Eastern Cooperative Oncology Group (ECOG) score (2,3 and 4) were constructed. The cut-off value of P-selectin for patients with cancer was identified to be different from that reported in the literature for the general population, and the models using D-dimer and P-selectin therefore have been demonstrated to be a potentially useful tool to be used in a panel of tests to predict TEEs, either independently or in a prediction score.

Statins: pros and cons

Statins inhibit the critical step of cholesterol synthesis in which 3-hydroxy-3-methylglutaryl coenzyme A (HMGC) is transformed to mevalonate by the enzyme HMGC reductase. By doing so, they have a potent lipid-lowering effect that reduces cardiovascular risk and decreases mortality. Since the mevalonate pathway also influences endothelial function, the inflammatory response, and coagulation, the effects of statins reach well beyond their cholesterol lowering properties. As with all drugs, statins may have adverse effects; these include musculoskeletal symptoms, increased risk of diabetes, and higher rates of hemorrhagic stroke. However, the frequency of adverse effects is extremely low and, in selected patient populations, the benefits of statins considerably outweigh the potential risks.

Optimal duration of anticoagulation

Once anticoagulation is stopped, the risk of recurrent venous thromboembolism (VTE) over years after a first episode is consistently around 30%. This risk is higher in patients with unprovoked than in those with (transient) provoked VTE, and among the latter in patients with medical than in those with surgical risk factors. Baseline parameters that have been found to be related to the risk of recurrent VTE are the proximal location of deep-vein thrombosis, obesity, old age, male sex and non-0 blood group, whereas the role of inherited thrombophilia is controversial. The persistence of residual vein thrombosis at ultrasound assessment has consistently been shown to increase the risk, as do persistently high values of D-dimer and the early development of the post-thrombotic syndrome. Although the latest international guidelines suggest indefinite anticoagulation for most patients with the first episode of unprovoked VTE, strategies that incorporate the assessment of residual vein thrombosis and D-dimer have the potential to identify subjects in whom anticoagulation can be safely discontinued. Moreover, new opportunities are offered by a few emerging anti-Xa and anti-IIa oral compounds, which are likely to induce fewer haemorrhagic complications than vitamin K antagonists while preserving the same effectiveness; and by low-dose aspirin, which has the potential to prevent the occurrence of both venous and arterial thrombotic events.

Weibel-Palade body size modulates the adhesive activity of its von Willebrand Factor cargo in cultured endothelial cells

Changes in the size of cellular organelles are often linked to modifications in their function. Endothelial cells store von Willebrand Factor (vWF), a glycoprotein essential to haemostasis in Weibel-Palade bodies (WPBs), cigar-shaped secretory granules that are generated in a wide range of sizes. We recently showed that forcing changes in the size of WPBs modifies the activity of this cargo. We now find that endothelial cells treated with statins produce shorter WPBs and that the vWF they release at exocytosis displays a reduced capability to recruit platelets to the endothelial cell surface. Investigating other functional consequences of size changes of WPBs, we also report that the endothelial surface-associated vWF formed at exocytosis recruits soluble plasma vWF and that this process is reduced by treatments that shorten WPBs, statins included. These results indicate that the post-exocytic adhesive activity of vWF towards platelets and plasma vWF at the endothelial surface reflects the size of their storage organelle. Our findings therefore show that changes in WPB size, by influencing the adhesive activity of its vWF cargo, may represent a novel mode of regulation of platelet aggregation at the vascular wall.

Use of statins and reduced risk of recurrence of VTE in an older population. A population-based cohort study

We aimed to determine whether statin use is associated with a decreased risk of recurrent venous thromboembolism (VTE) in older patients. We used a pre-assembled cohort of patients at least 65 years of age diagnosed with incident VTE between January 1, 1994 and December 31, 2004 in the province of Québec, Canada and followed until December 31, 2005. Time-dependent Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs) and 95 % confidence intervals (CIs) of recurrent VTE associated with current and past use of statins, compared with non-use. The cohort included 25,681 patients with incident VTE. During a mean follow-up of 3.0 years, there were 2343 recurrent VTE events (rate: 3.1 per 100 person-years). Compared with non-use, current use of statins was associated with a decreased risk of VTE recurrence (rates: 1.55 vs 3.47 per 100 per year, respectively; HR: 0.74, 95 % CI: 0.61-0.89), while no association was observed with past use (HR: 0.98, 95 % CI: 0.76-1.25). In a secondary analysis, longer durations of statin use were associated with greater risk reductions (0-6 months, HR 0.82, 95 % CI: 0.67-1.01; 6-12 months, HR 0.62, 95 % CI: 0.43-0.90; ≥ 12 months, HR: 0.50, 95 % CI: 0.33-0.74; p-value for trend ≤ 0.001). The use of statin was associated with a decreased risk of recurrent VTE in older patients. This study supports the need for randomised controlled trials to assess the efficacy and safety of statins in the long-term treatment of VTE.

Venous and Arterial Thrombosis: Is There a Link?

An increasing body of evidence suggests the likelihood of a link between venous and arterial thrombosis. The two vascular complications share several risk factors, such as age, obesity, smoking, diabetes mellitus, blood hypertension, hypertriglyceridemia, and metabolic syndrome. Moreover, there are many examples of conditions accounting for both venous and arterial thrombosis, such as the antiphospholipid antibody syndrome, hyperhomocysteinemia, malignancies, infections, and the use of hormonal treatment. Finally, several recent studies have consistently shown that patients with venous thromboembolism are at a higher risk of arterial thrombotic complications than matched control individuals. We, therefore, speculate the two vascular complications are simultaneously triggered by biological stimuli responsible for activating coagulation and inflammatory pathways in both the arterial and the venous system. Future studies are needed to clarify the nature of this association, to assess its extent, and to evaluate its implications for clinical practice.

Does the use of statins improve outcomes in coronary artery bypass graft surgery?

Statins (3-hydroxy-3-methylglutaryl CoA reductase inhibitors) are one of the most frequently prescribed medications throughout the world with beneficial effects that extend beyond their lipid-lowering activity. It has been suggested that statins may offer a simple and cost-effective strategy to reduce some of the complications that occur in association with coronary artery bypass graft (CABG) surgery. Limited existing randomized trial evidence in the setting of cardiac surgery suggests that statins may reduce the incidence of postoperative atrial fibrillation. However, any effect of statins on other outcomes is less clear. The clinical significance of specific statin agent and dose, acute statin withdrawal and the potential benefits associated with statin reloading remain important yet currently unresolved issues. Despite limited high-quality evidence, class I recommendations have been made that all patients undergoing coronary artery bypass graft surgery should receive statin therapy unless contraindicated.

Pleiotropic effects of statins

Statins or 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors not only prevents the synthesis of cholesterol biosynthesis but also inhibits the synthesis of essential isoprenoid intermediates such as farnesyl pyrophosphate, geranylgeranyl pyrophosphate, isopentanyl adenosine, dolichols and polyisoprenoid side chains of ubiquinone, heme A, and nuclear lamins. These isoprenoid intermediates are required for activation of various intracellular/signaling proteins- small guanosine triphosphate bound protein Ras and Ras-like proteins like Rho, Rab, Rac, Ral, or Rap which plays an indispensible role in multiple cellular processes. Reduction of circulating isoprenoids intermediates as a result of HMG CoA reductase inhibition by statins prevents activation of these signalling proteins. Hence, the multiple effects of statins such as antiinflammatory effects, antioxidant effects, antiproliferative and immunomodulatory effects, plaque stability, normalization of sympathetic outflow, and prevention of platelet aggregation are due to reduction of circulating isoprenoids and hence inactivation of signalling proteins. These multiple lipid-independent effects of statins termed as statin pleiotropy would potentially open floodgates for research in multiple treatment domains catching attentions of researchers and clinician across the globe.

Is lipid lowering therapy an independent risk factor for venous thromboembolism? A population-based case-control study

INTRODUCTION

The independent effect of lipid lowering therapy (LLT) on venous thromboembolism (VTE) risk is uncertain.

OBJECTIVE

To test statin and non-statin LLT as potential VTE risk factors.

METHODS

Using Rochester Epidemiology Project resources, we identified all Olmsted County, MN residents with objectively diagnosed incident VTE (cases) over the 13-year period, 1988-2000 (n=1340), and one to two matched controls (n=1538). We reviewed their complete medical records for baseline characteristics previously identified as independent VTE risk factors, and for statin and non-statin LLT. Using conditional logistic regression, we tested the overall effect of LLT on VTE risk and also separately explored the role of statin versus that of non-statin LLT, adjusting for other baseline characteristics.

RESULTS

Among cases and controls, 74 and 111 received statin LLT, and 32 and 50 received non-statin LLT, respectively. Univariately, and after individually controlling for other potential VTE risk factors (i.e., BMI, trauma/fracture, leg paresis, hospitalization for surgery or medical illness, nursing home residence, active cancer, central venous catheter, varicose veins, prior superficial vein thrombosis, diabetes, congestive heart failure, angina/myocardial infarction, stroke, peripheral vascular disease, smoking, anticoagulation), LLT was associated with decreased odds of VTE (unadjusted OR=0.73; p=0.03). When considered separately, statin and non-statin LLT were each associated with moderate, non-significant lower odds of VTE. After adjusting for angina/myocardial infarction, each was significantly associated with decreased odds of VTE (OR=0.63, p<0.01 and OR=0.61, p=0.04, respectively).

CONCLUSIONS

LLT is associated with decreased VTE risk after adjusting for known risk factors.

Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy

BACKGROUND

Patients with schizophrenia are at increased risk of venous thromboembolism. The mechanisms underlying this association are poorly understood.

AIMS

We investigated whether there is a global hypercoagulable state in patients with schizophrenia utilising the overall haemostatic potential (OHP) assay which assesses overall coagulation potential (OCP), haemostatic potential (OHP) and fibrinolytic potential (OFP).

METHOD

Citrated plasma was collected for OHP assays from patients with schizophrenia on long-term antipsychotic treatment and compared with healthy age- and sex-matched controls. Time courses of fibrin formation and degradation were measured by spectrophotometry (absorption of 405nm) after the addition of tissue factor and tissue plasminogen activator to plasma.

RESULTS

Ninety patients with schizophrenia (antipsychotic treatment-15.9±9.7years) and 30 controls were recruited. Patients with schizophrenia had higher rates of smoking and levels of inflammatory markers (high-sensitivity C-reactive protein and neutrophil-to-lymphocyte ratio) than controls. Whilst D-dimer, fibrinogen and platelet count did not differ between patients with schizophrenia and controls, the OCP (54.0±12.6 vs 45.9±9.1, p=0.002) and OHP (12.6±5.8 vs 7.2±3.7, p<0.001) were higher, and OFP was lower (76.6±9.8% vs 84.9±6.4%, p<0.001) in patients with schizophrenia, implying both a hypercoagulable and hypofibrinolytic state in these patients. Importantly, abnormalities in overall coagulation were independently predicted by levels of plasminogen-activator-inhibitor-1, fibrinogen, platelet count, inflammatory markers and plasma triglycerides, suggesting a multifactorial aetiology.

CONCLUSION

Patients with schizophrenia have evidence of a global hypercoagulable and hypofibrinolytic state which may contribute to their increased risk of venous thromboembolism.

Statins for primary prevention of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is common in clinical practice. The efficacy of statins in the primary prevention of VTE remains unproven. This is an update of the review first published in 2011.

OBJECTIVES

To assess the efficacy of statins in the primary prevention of VTE.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases (PVD) Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and CENTRAL (2014, Issue 1).

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed statins in the primary prevention of VTE were considered. The outcomes we evaluated were the rates of VTE, cardiovascular and cerebrovascular events, death and adverse events. Two authors (L Li, JH Tian) independently selected RCTs against the inclusion criteria. Disagreements were resolved by discussion with a third author (KH Yang).

DATA COLLECTION AND ANALYSIS

Data extraction was independently carried out by two authors (L Li, JH Tian). Disagreements were resolved by discussion with a third author (PZ Zhang). Two authors (L Li, JH Tian) independently assessed the risk of bias according to a standard quality checklist provided by the PVD Group.

MAIN RESULTS

For this update we included one RCT with 17,802 participants that assessed rosuvastatin compared with placebo for the prevention of VTE. The quality of the evidence was moderate because of imprecision, as the required sample size for the outcomes of this review was not achieved. Analysis showed that when compared with placebo rosuvastatin reduced the incidence of VTE (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.86) and deep vein thrombosis (DVT) (OR 0.45, 95% CI 0.25 to 0.79), the risk of any (fatal and non-fatal) myocardial infarction (MI) (OR 0.45, 95% CI 0.30 to 0.69), and any (fatal and non-fatal) stroke (OR 0.51, 95% CI 0.34 to 0.78). There was no difference in the incidence of pulmonary embolism (PE) (OR 0.77, 95% CI 0.41 to 1.46), fatal MI (OR 1.50, 95% CI 0.53 to 4.22), fatal stroke (OR 0.30, 95% CI 0.08 to 1.09) or death after VTE (OR 0.50, 95% CI 0.20 to 1.24). The incidence of any serious adverse events was no different between the rosuvastatin and placebo groups (OR 1.07, 95% CI 0.95 to 1.20).

AUTHORS' CONCLUSIONS

Available evidence showed that rosuvastatin was associated with a reduced incidence of VTE, but the evidence was limited to a single RCT and any firm conclusions and suggestions could be not drawn. Randomised controlled trials of statins (including rosuvastatin) are needed to evaluate their efficacy in the prevention of VTE.

Influence of statin use on the incidence of recurrent venous thromboembolism and major bleeding in patients receiving rivaroxaban or standard anticoagulant therapy

Background

Statins may reduce the risk of first and recurrent venous thromboembolism (VTE). No data are available on their potential benefit in patients treated with the oral anticoagulant rivaroxaban.

Methods

The EINSTEIN DVT/PE and EINSTEIN Extension studies compared rivaroxaban with standard of care (n=8280) and placebo (n=1188), respectively. The incidences of recurrent VTE and major bleeding per 100 patient-years for exposure (or not) to statins were calculated. A Cox proportional hazards model was constructed, stratified by index event and intended treatment duration, with statin use as a time-dependent variable, for each treatment group (rivaroxaban vs enoxaparin/vitamin K antagonist or placebo) and adjusted for relevant variables.

Results

In EINSTEIN DVT/PE, 1509 (18.3%) patients used statins during the at-risk period, and 6731 (81.7%) did not. Overall, 2.6 recurrent VTEs occurred per 100 patient-years with statin use compared with 3.8 per 100 patient-years without statins (adjusted hazard ratio [HR] 0.76; 95% confidence interval [CI] 0.46–1.25). HRs for recurrent VTE were similar for concomitant use of rivaroxaban-statin and enoxaparin/VKA-statin. Major bleeding events occurred in 3.0 per 100 patient-years with statin use compared with 2.3 per 100 patient-years without statins (adjusted HR 0.77; 95% CI 0.46–1.29). Due to adjustments in the Cox regression model, the direction of this HR is in contrast to the crude comparison. In EINSTEIN Extension, no recurrent VTEs occurred with statin use in the rivaroxaban group compared with 1.6 per 100 patient-years without statins. In the placebo group, 12.2 recurrent VTEs occurred per 100 patient-years with statin use compared with 13.2 per 100 patient-years without (adjusted HR 0.81; 95% CI 0.35–1.86).

Conclusions

The effect of statins in this secondary analysis of the EINSTEIN VTE treatment program is consistent with other studies that suggest a reduced risk of recurrent VTE, but conclusive evidence of this benefit is lacking. Statins are simple to use, inexpensive, very safe and do not cause bleeding. Therefore, the potential effect on reducing recurrent VTE, which is in the range of that of acetylsalicylic acid, deserves evaluation in a large randomized trial.

Trial registration number

ClinicalTrials.gov: EINSTEIN PE, NCT00439777; EINSTEIN DVT, NCT00440193; EINSTEIN Extension, NCT00439725.

Statins are associated with low risk of venous thromboembolism in patients with cancer: a prospective and observational cohort study

INTRODUCTION

Patients with cancer are at risk of venous thromboembolism (VTE). Statin-use has been shown to be associated with low risk of VTE in patients without cancer, but data in cancer patients is scarce. The objective of this study was to evaluate the association of statins with risk of VTE in cancer patients in a prospective observational cohort study.

MATERIALS AND METHODS

Patients with newly diagnosed cancer or progression of disease after remission were included and prospectively followed for a maximum of 2 years. Study endpoint was occurrence of symptomatic VTE.

RESULTS

Patients (n=1434) were followed over a median observation period of 729 days. VTE occurred in 107 (7.5%) patients. At study inclusion, 170 (11.9%) patients took statins. Simvastatin (n=96) and atorvastatin (n=48) were the most frequently prescribed statins. VTE occurred in 6 (3.5%) patients with statins. Patients with statins had a lower risk of VTE than patients without (subhazard ratio 0.43, 95% confidence interval 0.19 to 0.98; p=0.04). In competing risk analysis, the cumulative probability of VTE in patients with statins was 2.94% after 12 months and 3.54% after 24 months, compared to 7.13% and 8.13% in the group without statins (Gray's test: p=0.04).

CONCLUSION

This study provides observational evidence for an association between statin use and low risk of VTE in patients with cancer. The role of statins for prevention of cancer-associated VTE needs to be confirmed in randomized, controlled trials.

Statins and venous thromboembolic disease prophylaxis

Statins have dramatically improved the treatment of hyperlipidemia and cardiovascular disease through its inhibition of hydroxymethylglutaryl-coenzyme A reductase. Although its main effect has long been known, much is yet to be understood about the wide and varied pleiotropic properties of statins. Some studies have demonstrated that statins contain antiplatelet, antithrombotic, antiinflammatory, cardioprotective, and neuroprotective properties independent of their ability to lower plasma low-density lipoprotein cholesterol. More recently, statins have been used in novel ways in the treatment of Alzheimer disease, sepsis, pneumonia, and bacteremia. In 2000, it was first suggested that statins could decrease the incidence of venous thromboembolisms (VTEs). A recent publication showed that not only do statins lower the incidence of deep vein thrombosis and pulmonary embolism, but they do so in a dose-dependent manner. Although there is certainly strong evidence demonstrating that statins do indeed lower VTEs, the mechanism is not understood. Possible hypotheses include their antiinflammatory and antithrombotic properties. With only one randomized clinical trial available, further studies must be conducted before routinely recommending statins for prophylaxis of VTEs.

The association between statin therapy during intensive care unit stay and the incidence of venous thromboembolism: a propensity score-adjusted analysis

Background

Studies have shown that statins have pleiotropic effects on inflammation and coagulation; which may affect the risk of developing venous thromboembolism (VTE). The objective of this study was to evaluate the association between statin therapy during intensive care unit (ICU) stay and the incidence of VTE in critically ill patients.

Methods

This was a post-hoc analysis of a prospective observational cohort study of patients admitted to the intensive care unit between July 2006 and January 2008 at a tertiary care medical center. The primary endpoint was the incidence of VTE during ICU stay up to 30 days. Secondary endpoint was overall 30-day hospital mortality. Propensity score was used to adjust for clinically and statistically relevant variables.

Results

Of the 798 patients included in the original study, 123 patients (15.4%) received statins during their ICU stay. Survival analysis for VTE risk showed that statin therapy was not associated with a reduction of VTE incidence (crude hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.28-1.54, P = 0.33 and adjusted HR 0.63, 95% CI 0.25-1.57, P = 0.33). Furthermore, survival analysis for hospital mortality showed that statin therapy was not associated with a reduction in hospital mortality (crude HR 1.26, 95% CI 0.95-1.68, P = 0.10 and adjusted HR 0.98, 95% CI 0.72-1.36, P = 0.94).

Conclusion

Our study showed no statistically significant association between statin therapy and VTE risk in critically ill patients. This question needs to be further studied in randomized control trials.

Update on pharmacologic therapy for pulmonary embolism

Warfarin, unfractionated heparin (UFH), and low-molecular-weight heparins are anticoagulants that have been used for treatment of pulmonary embolism. Currently approved drugs for treatment of venous thromboembolism include UFH, enoxaparin, dalteparin, fondaparinux, warfarin, and rivaroxaban. The advent of newer oral anticoagulants such as rivaroxaban, dabigatran, and apixaban has provided us with alternative therapeutic options for long-term anticoagulation. This article will give an overview of the various anticoagulant drugs, use in various clinical scenarios, data supporting their clinical use, and recommendations regarding duration of anticoagulant therapy.

Prevention of venous thromboembolism in patients with hemorrhagic stroke

Deep venous thrombosis (DVT) and pulmonary embolism (PE) are part of the spectrum of venous thromboembolism (VTE). It is one of the most frequent medical complications in stroke patients. The risk of VTE is even higher after hemorrhagic stroke. This article reviews various screening methods, diagnostic techniques, and pharmacologic as well as nonpharmacologic means of preventing VTE after hemorrhagic stroke.

Prophylaxis of Thromboembolic Events in Patients with Nephrotic Syndrome

OBJECTIVE

To review published literature regarding use of strategies to prevent thrombotic events in patients with nephrotic syndrome (NS).

DATA SOURCES

The MEDLINE/PubMed, EMBASE, and Cochrane databases were queried from 1980 to December 2012 for articles in English using the search terms nephrotic syndrome, thrombosis, thromboembolism, anticoagulation, warfarin, heparin, low-molecular-weight heparin, enoxaparin, dalteparin, tinzaparin, statin, atorvastatin, fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin, simvastatin, aspirin, direct thrombin inhibitor, rivaroxaban, argatroban, lepirudin, bivalirudin, dabigatran, factor Xa inhibitor, fondaparinux, rivaroxaban, clopidogrel, ticlopidine, and prasugrel.

STUDY SELECTION AND DATA EXTRACTION

All relevant original studies, meta-analyses, systematic reviews, guidelines, and review articles were assessed for inclusion. References from pertinent articles were examined for additional content not found during the initial search.

DATA SYNTHESIS

NS leads to multiple complications, including hypercoagulability. A small prospective cohort study used enoxaparin for primary prophylaxis and demonstrated successful prevention of thrombotic events with minimal adverse events. Additional information has come in the form of decision analyses, which show potential decreased morbidity and mortality when primary prophylaxis for thrombotic events is used; however, all data have numerous limitations. Other strategies for thrombus prevention, including statins and antiplatelet agents, also have been investigated.

CONCLUSIONS

When patients with NS are admitted to the hospital, develop an acute medical illness, or acquire an additional thrombotic events risk factor such as surgery, active malignancy, or pregnancy, consideration for primary pharmacologic prophylaxis with appropriately dosed low-molecular-weight heparin or other indicated anticoagulant should include the potential for increased thrombotic events risk in this patient population. Consideration may also be given to the use of primary pharmacologic prophylaxis with low-molecular-weight heparin or oral vitamin K antagonist in patients with membranous nephropathy once the albumin level drops below 2.0–2.5 g/dL. Short-term use of pharmacologic prophylaxis during the first 6 months following diagnosis warrants further investigation.

Statins for the prevention of venous thromboembolism? a narrative review

Venous thromboembolism (VTE), including deep vein thrombosis and pulmonary embolism, is a substantial public health problem. The majority of VTE events are associated with transient periods of heightened risk, such as prolonged hospitalization, undergoing major surgery, experiencing trauma or lower extremity immobility, use of oral contraceptives, or having active cancer. Although pharmacologic thromboprophylaxis agents (eg, unfractionated heparin, low-molecular-weight heparins, warfarin, and novel oral anticoagulants) are effective, they remain underused, with concerns about increased bleeding risk often cited as a reason. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (ie, statins), although used primarily for lipid lowering and arterial thrombosis risk reduction, have pleiotrophic effects that affect coagulation and inflammation, and do not increase bleeding risk. There is emerging evidence to suggest that through these pleiotrophic effects, statins may be effective in reducing the incidence of VTE. This article summarizes the literature with regard to statins' effect on VTE and suggests that additional investigations are needed to assess a potential adjunctive role for primary VTE thromboprophylaxis.

Sources of tissue factor that contribute to thrombosis after rupture of an atherosclerotic plaque

Hyperlipidemia leads to the formation of oxidized LDL (oxLDL), vessel dysfunction, atherosclerotic disease, and ultimately to plaque rupture and thrombosis. OxLDL induces tissue factor (TF) expression in various cell types, including monocytes and macrophages. High levels of TF are present in atherosclerotic plaques and this represents that major source of TF that triggers thrombosis after plaque rupture. In addition, increased levels of "circulating TF" are observed in hyperlipidemic animals and patients. This is due to induced TF expression in monocytes and release of monocyte-derived, TF(+) microparticles, which represents a minor source of TF that likely contributes to thrombosis after plaques rupture. This review will summarize the connections between hyperlipidemia and TF expression within atherosclerotic plaques and circulating monocytes, as well as its inhibition by statins.

Effect of statins and anticoagulants on prostate cancer aggressiveness

PURPOSE

Statins and anticoagulants (ACs) have both been associated with a less-aggressive prostate cancer (PCa) and a better outcome after treatment of localized PCa. The results of these studies might have been confounded because patients might often take both medications. We examined their respective influence on PCa aggressiveness at initial diagnosis.

MATERIALS AND METHODS

We analyzed 381 patients treated with either external beam radiotherapy or brachytherapy for low-risk (n = 152), intermediate-risk (n = 142), or high-risk (n = 87) localized PCa. Univariate and multivariate logistic regression analyses were used to investigate an association between these drug classes and prostate cancer aggressiveness. We tested whether the concomitant use of statins and ACs had a different effect than that of either AC or statin use alone.

RESULTS

Of the 381 patients, 172 (45.1%) were taking statins and 141 (37.0%) ACs; 105 patients (27.6%) used both. On univariate analysis, the statin and AC users were associated with the prostate-specific antigen (PSA) level (p = .017) and National Comprehensive Cancer Network risk group (p = .0022). On multivariate analysis, statin use was associated with a PSA level <10 ng/mL (odds ratio, 2.9; 95% confidence interval, 1.3-6.8; p = .012) and a PSA level >20 ng/mL (odds ratio, 0.29; 95% confidence interval, 0.08-0.83; p = .03). The use of ACs was associated with a PSA level >20 ng/mL (odds ratio, 0.13; 95% confidence interval, 0.02-0.59, p = .02).

CONCLUSION

Both AC and statins have an effect on PCa aggressiveness, with statins having a more stringent relationship with the PSA level, highlighting the importance of considering statin use in studies of PCa aggressiveness.

Statins for primary prevention of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is common in clinical practice. The efficacy of statins in the primary prevention of VTE remains unproven.

OBJECTIVES

To assess the efficacy of statins in the primary prevention of VTE.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases (PVD) Group searched their Specialised Register (last searched April 2011) and CENTRAL (2011, Issue 2). The authors searched MEDLINE (January 1966 to March 2011); EMBASE (1974 to March 2011); ISI Web of Knowledge (2001 to March 2011); the Chinese Biomedical Literature Database (1978 to March 2011) and other resources (including clinical trials registers, reference lists and presentations at various conferences.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed statins were considered. The outcomes we evaluated were the rates of VTE, cardiovascular and cerebrovascular events, death and adverse events. Two authors independently selected RCTs against inclusion criteria. Disagreements were resolved by discussion with a third author.

DATA COLLECTION AND ANALYSIS

Data extraction was independently carried out by two authors. Disagreements were resolved by discussion with a third author. Two authors independently assessed the risk of bias according to a standard quality checklist provided by the PVD Group.

MAIN RESULTS

We included one RCT (17 citations) with 17,802 participants that assessed rosuvastatin for preventing VTE. Our analysis showed that rosuvastatin reduced the incidence of VTE (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.86) and deep vein thrombosis (DVT) (OR 0.45, 95% CI 0.25 to 0.79), the risk of any (fatal and non-fatal) myocardial infarction (MI) (OR 0.45, 95% CI 0.30 to 0.69), any (fatal and non-fatal) stroke (OR 0.51, 95% CI 0.34 to 0.78), but did not reduce the incidence of pulmonary embolism (PE) (OR 0.77, 95% CI 0.41 to 1.46) and death after VTE (OR 0.50, 95% CI 0.20 to 1.24). Rosuvastatin did not reduce the incidence of any serious adverse event (OR 0.95, 95% CI 0.90 to 1.06).

AUTHORS' CONCLUSIONS

Available evidence showed that rosuvastatin was associated with a reduced incidence of VTE, but the evidence was limited to a single RCT. Randomised controlled trials of statins (including rosuvastatin) are needed to evaluate the efficacy of statins in the prevention of VTE.

Impact of HMG-CoA reductase inhibitor (statin) use on blood loss during robot-assisted and open radical prostatectomy

BACKGROUND AND PURPOSE

In addition to their lipid lowering effects, HMG-CoA reductase inhibitors (statins) have been shown to exert antithrombotic effects through downregulation of the coagulation cascade. Because statin use is widespread, it is important to understand the impact of these drugs on blood loss (BL) during surgery. We studied the impact of statin use on BL during robot-assisted radical prostatectomy (RARP) and open radical prostatectomy (ORP).

PATIENTS AND METHODS

A retrospective review was conducted of a database approved by the Institutional Review Board for patients who underwent RARP or ORP at a single academic institution. Patients were categorized as statin-users or statin-naïve at the time of surgery. Patient demographic information was recorded as was perioperative data, including preoperative and postoperative hematocrit (Hct) value. BL was defined as % Hct change presurgery vs postsurgery. In addition, the outcome of ≥10% drop in Hct was studied. The t test and chi-square analysis were used to compare variables across statin use groups. Univariate and multivariable logistic regression analyses were used to identify factors that impacted BL.

RESULTS

From 1987 to 2010, 3578 patients underwent prostatectomy for prostate cancer (RARP=945 and ORP=2633). Of these, 676 men were identified as statin-users and 2902 as statin-naïve. Mean patient age was 60.2±7.0 years. Statin-users were found to be older (P<0.001), have lower mean preoperative prostate-specific antigen (PSA) levels (P=0.002), and have higher pathologic Gleason sum scores (P<0.001). For ORP, statin use was associated with increased BL with Hct % change of 20.7% for users vs18.6% for nonusers, (P<0.001). For RARP, no significant change in Hct was seen with statin use with % changes of 12.6% and 12.5%, respectively (P=0.9). When controlling for age, Gleason sum, surgeon, date of surgery and PSA level, statin use was associated with increased BL (P=0.04).

CONCLUSION

Even when controlling for age, Gleason sum, surgeon, date of surgery, and PSA, statin use is associated with increased BL during RP. This information may impact preoperative planning and patient counseling for men who are taking statins while preparing for RP.