The risk of overanticoagulation in patients with heart failure on coumarin anticoagulants

Effect of MEF2A and SLC22A3-LPAL2-LPA gene polymorphisms on warfarin sensitivity and responsiveness in Jordanian cardiovascular patients

AIMS

This study aims to investigate the influence of MEF2A and SLC22A3-LPAL2-LPA polymorphisms on cardiovascular disease susceptibility and responsiveness to warfarin medication in Jordanian patients, during the initiation and maintenance phases of treatment.

BACKGROUNDS

Several candidate genes have been reported to be involved in warfarin metabolism and studying such genes may help in finding an accurate way to determine the needed warfarin dose to lower the risk of adverse drug effects, resulting in more safe anticoagulant therapy.

METHODS

The study population included 212 cardiovascular patients and 213 healthy controls. Genotyping of MEF2A and SLC22A3-LPAL2-LPA polymorphisms was conducted to examine their effects on warfarin efficiency and cardiovascular disease susceptibility using PCR-based methods.

RESULTS

One SNP (SLC22A3-LPAL2-LPA rs10455872) has been associated with cardiovascular disease in the Jordanian population, whereas the other SNPs in the MEF2A gene and SLC22A3-LPAL2-LPA gene cluster did not have any significant differences between cardiovascular patients and healthy individuals. Moreover, SLC22A3-LPAL2-LPA rs10455872 was correlated with moderate warfarin sensitivity, the other SNPs examined in the current study have not shown any significant associations with warfarin sensitivity and responsiveness.

CONCLUSION

Our data refer to a lack of correlation between the MEF2A polymorphism and the efficacy of warfarin treatment in both phases of treatment, the initiation, and maintenance phases. However, only rs10455872 SNP was associated with sensitivity to warfarin during the initiation phase. Furthermore, rs3125050 has been found to be associated with the international normalized number treatment outcomes in the maintenance phase.

Therapeutic Effects of Coumarins with Different Substitution Patterns

The use of derivatives of natural and synthetic origin has gained attention because of their therapeutic effects against human diseases. Coumarins are one of the most common organic molecules and are used in medicine for their pharmacological and biological effects, such as anti-inflammatory, anticoagulant, antihypertensive, anticonvulsant, antioxidant, antimicrobial, and neuroprotective, among others. In addition, coumarin derivates can modulate signaling pathways that impact several cell processes. The objective of this review is to provide a narrative overview of the use of coumarin-derived compounds as potential therapeutic agents, as it has been shown that substituents on the basic core of coumarin have therapeutic effects against several human diseases and types of cancer, including breast, lung, colorectal, liver, and kidney cancer. In published studies, molecular docking has represented a powerful tool to evaluate and explain how these compounds selectively bind to proteins involved in various cellular processes, leading to specific interactions with a beneficial impact on human health. We also included studies that evaluated molecular interactions to identify potential biological targets with beneficial effects against human diseases.

Spontaneous sublingual hematoma secondary to warfarin therapy—A rare complication

Warfarin is the most commonly prescribed oral anticoagulant in Nepal. It is commonly used for chronic anticoagulation in patients with atrial fibrillation, venous thromboembolism, and artificial heart valves. The major side effect of warfarin is bleeding. Though extremely rare, a sublingual hematoma can lead to life‐threatening complications as it can cause severe airway obstruction. We present a case of a 55‐year‐old female patient who had sublingual hematoma secondary to the use of Warfarin therapy. In addition to the discontinuation of warfarin, she was managed conservatively without any surgical intervention. Early diagnosis, timely discontinuation of the drug, and application of appropriate medical treatment are of utmost importance for reducing morbidity and mortality due to bleeding and airway compromise.

Isolated sublingual hematoma is a rare complication of warfarin treatment. We report a case of a 55‐year‐old woman with complaints of swelling below the tongue and upper neck and difficulty in swallowing and was successfully managed.

Anticoagulation versus placebo for heart failure in sinus rhythm

BACKGROUND

People with chronic heart failure (HF) are at risk of thromboembolic events, including stroke, pulmonary embolism, and peripheral arterial embolism; coronary ischaemic events also contribute to the progression of HF. The use of long-term oral anticoagulation is established in certain populations, including people with HF and atrial fibrillation (AF), but there is wide variation in the indications and use of oral anticoagulation in the broader HF population.

OBJECTIVES

To determine whether long-term oral anticoagulation reduces total deaths and stroke in people with heart failure in sinus rhythm.

SEARCH METHODS

We updated the searches in CENTRAL, MEDLINE, and Embase in March 2020. We screened reference lists of papers and abstracts from national and international cardiovascular meetings to identify unpublished studies. We contacted relevant authors to obtain further data. We did not apply any language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCT) comparing oral anticoagulants with placebo or no treatment in adults with HF, with treatment duration of at least one month. We made inclusion decisions in duplicate, and resolved any disagreements between review authors by discussion, or a third party.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, and assessed the risks and benefits of antithrombotic therapy by calculating odds ratio (OR), accompanied by the 95% confidence intervals (CI).

MAIN RESULTS

We identified three RCTs (5498 participants). One RCT compared warfarin, aspirin, and no antithrombotic therapy, the second compared warfarin with placebo in participants with idiopathic dilated cardiomyopathy, and the third compared rivaroxaban with placebo in participants with HF and coronary artery disease. We pooled data from the studies that compared warfarin with a placebo or no treatment. We are uncertain if there is an effect on all-cause death (OR 0.66, 95% CI 0.36 to 1.18; 2 studies, 324 participants; low-certainty evidence); warfarin may increase the risk of major bleeding events (OR 5.98, 95% CI 1.71 to 20.93, NNTH 17). 2 studies, 324 participants; low-certainty evidence). None of the studies reported stroke as an individual outcome. Rivaroxaban makes little to no difference to all-cause death compared with placebo (OR 0.99, 95% CI 0.87 to 1.13; 1 study, 5022 participants; high-certainty evidence). Rivaroxaban probably reduces the risk of stroke compared to placebo (OR 0.67, 95% CI 0.47 to 0.95; NNTB 101; 1 study, 5022 participants; moderate-certainty evidence), and probably increases the risk of major bleeding events (OR 1.65, 95% CI 1.17 to 2.33; NNTH 79; 1 study, 5008 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Based on the three RCTs, there is no evidence that oral anticoagulant therapy modifies mortality in people with HF in sinus rhythm. The evidence is uncertain if warfarin has any effect on all-cause death compared to placebo or no treatment, but it may increase the risk of major bleeding events. There is no evidence of a difference in the effect of rivaroxaban on all-cause death compared to placebo. It probably reduces the risk of stroke, but probably increases the risk of major bleedings. The available evidence does not support the routine use of anticoagulation in people with HF who remain in sinus rhythm.

Oral Anticoagulation and Adverse Outcomes after Ischemic Stroke in Heart Failure Patients without Atrial Fibrillation

BACKGROUND

The safety and effectiveness of oral anticoagulation (OAC) after an ischemic stroke in older patients with heart failure (HF) without atrial fibrillation remains uncertain.

METHODS

Utilizing Get With The Guidelines Stroke national clinical registry data linked to Medicare claims from 2009-2014, we assessed the outcomes of eligible patients with a history of HF who were initiated on OAC during a hospitalization for an acute ischemic stroke. The cumulative incidences of adverse events were calculated using Kaplan-Meier curves and adjusted Cox proportional hazard ratios were compared between patients discharged on or off OAC.

RESULTS

A total of 8,261 patients from 1,370 sites were discharged alive after an acute ischemic stroke and met eligibility criteria. Of those, 747 (9.0%) were initiated on OAC.  Patients on OAC were younger (77.2±8.0 vs. 80.5±8.9 years, p<0.01). After adjustment for clinical covariates, the likelihood of 1 year mortality was higher in those on OAC (aHR: 1.22, 95% CI 1.05-1.41, p<0.01), while no significant differences were noted for ICH (aHR: 1.34, 95% CI 0.69-2.59, p=0.38) and recurrent ischemic stroke (aHR: 0.78, 95% CI 0.54-1.15, p = 0.21).  The likelihood of all-cause bleeding (aHR: 1.59, 95% CI 1.29-1.96, p<0.01) and all-cause re-hospitalization (aHR: 1.14, 95% CI 1.02-1.27, p = 0.02) was higher for those on OAC.

CONCLUSION

Initiation of OAC after an ischemic stroke in older patients with HF in the absence of atrial fibrillation is associated with death, bleeding and re-hospitalization without an associated reduction in recurrent ischemic stroke. If validated, these findings raise caution for prescribing OAC to such patients.

Impact of PCSK9, WDR12, CDKN2A, and CXCL12 Polymorphisms in Jordanian Cardiovascular Patients on Warfarin Responsiveness and Sensitivity

Background

The main objective of this study is sought to determine the impacts of PCSK9, WDR12, CDKN2A, and CXCL12 polymorphisms on warfarin sensitivity and responsiveness in Jordanian cardiovascular patients during the initiation and stabilization phases of therapy.

Methods

This study took place at the anticoagulation clinic at Queen Alia Heart Institute (QAHI) in Jordan. DNA samples were collected from 212 cardiovascular patients and 213 healthy controls. Genomic SNPs genotyping was conducted using the MassARRAY System at the Australian Genome Research Facility.

Results

This study assessed 10 polymorphisms (rs11206510 within the PCSK9 gene, rs6725887 and rs7582720 within the WDR12 gene, rs4977574, rs10757278, and rs1333049 within the CDKN2A gene, rs2862116, rs7906426, rs1746048, and rs268322 within the CXCL12 gene) in 212 Jordanian cardiovascular patients. Carriers of CDKN2A rs1333049, rs10757278, and PCSK9 rs11206510 polymorphisms had an increased risk of resistance during the initiation phase of warfarin therapy compared to those who do not carry it, or those who are carrying one polymorphism only (P < 0.05), while carriers of CXCL12 rs7906426 polymorphism had similar increased risk but during the stabilization phase of warfarin therapy (P < 0.05).

Conclusion

Carriers of CXCL12 rs2862116 polymorphism had an increased risk to be warfarin extensive responders compared to those with no or only one polymorphism (P = 0.01). However, the presence of PCSK9 rs11206510 polymorphism affects the warfarin maintenance doses (P ˃ 0.0001).

Anticoagulant treatment and bleeding complications in patients with left ventricular assist devices

INTRODUCTION

The treatment options for advanced heart failure patients drastically changed with the introduction of left ventricular assist devices (LVADs), either as bridge to transplant or as destination therapy for patients ineligible for transplant. Despite major benefits in terms of survival, functional status and quality of life, managing patients with LVADs comes with several challenges. The most significant challenge is balancing between the risks of thrombotic and bleeding complications.

AREAS COVERED

The present review describes the pathophysiological mechanisms explaining the alterations in the hemostatic profile of LVAD patients, and summarizes current evidence to guide clinical decision making with regard to anticoagulant treatment and management of bleeding complications.

EXPERT OPINION

LVAD patients require life-long anticoagulant therapy to reduce the risk of pump thrombosis. However, exposing LVAD patients to anticoagulant therapy, in combination with common acquired coagulopathies after LVAD implantation such as acquired von Willebrand syndrome, comes with high risks of bleeding. There is a need for randomized controlled trials in LVAD patients to determine the optimal antithrombotic regimen and find the most effective balance between thrombotic and bleeding complications. In addition, strategies to specifically target the acquired von Willebrand syndrome and its associated angiodysplasias need to be evaluated in the LVAD population.

Evaluation of the effects of ontogenetic or maturation functions and chronic heart failure on the model analysis for the dose-response relationship of warfarin in Japanese children

PURPOSE

We previously demonstrated that the rational pediatric dosage of warfarin can be well-described by a SIZE parameter that includes an allometry exponent of weight. On the other hand, allometry alone is considered to be insufficient to predict drug clearance in neonates and infants. The primary purpose of the present study was to evaluate the effects of incorporation of the maturation process into the analysis model for the dose-response relationship of warfarin in Japanese children. In addition, we evaluated the effect of chronic heart failure (CHF) on the response to warfarin as an independent risk factor for increased anticoagulant effects.

METHODS

Thirty-eight patients with stable anticoagulation by warfarin were enrolled. During a mean follow-up period of 4.74 ± 3.51 years, 1092 data points including prothrombin time-international normalized ratio (PT-INR) were obtained. The data were subjected to multiple regression analysis to identify covariates related to the anticoagulant effects.

RESULTS

Two different models describing the maturation process did not improve the predictive performance for the dose-response relationship in pediatric patients. In addition to the SIZE-normalized daily dose, the vitamin K epoxide reductase complex 1 (VKORC1) genotype, and concomitant use of bosentan, CHF was identified as a covariate increasing the anticoagulant effects of warfarin to 118%.

CONCLUSION

The SIZE parameter was useful even without incorporation of maturation models to describe the response to warfarin in pediatric patients, and our longitudinal follow-up study design with multiple observations was beneficial to detect changes within individual subjects.

Effects of CYP2C9 and VKORC1 polymorphisms on warfarin sensitivity and responsiveness during the stabilization phase of therapy

The main objective of this study is to assess the effects of CYP2C9 and VKORC1 polymorphisms on warfarin sensitivity and responsiveness in a Jordanian population during the stabilization phase of treatment. This study was conducted at the Queen Alia Heart Institute (QAHI) anticoagulation clinic in Amman, Jordan. We assessed three CYP2C9 (rs1799853, rs1057910, rs4086116) and four VKORC1 (rs10871454, rs8050894, rs9934438, rs17708472) polymorphisms in 139 Jordanian cardiovascular patients. Demographic and clinical data were also collected. Of the 139 patients in the cohort, 80% had the VKORC1 polymorphisms rs10871454 and rs9934438, while 22.3% and 24.5% of patients had the rs1799853 and rs1057910 CYP2C9 alleles, respectively. Carriers of the CYP2C9 polymorphisms rs1057910 and rs4086116 had an increased risk of warfarin sensitivity compared to subjects with no or only one polymorphism. Similarly, carriers of all four VKORC1 variants had an increased risk of warfarin sensitivity (over anticoagulation) compared to those with no or only one polymorphism. Patients with a CYP2C9 or VKORC1 polymorphism required significantly lower doses than patients with no polymorphisms. The presence of any of CYP2C9 or VKORC1 polymorphisms is associated with sensitivity to warfarin during the stabilization period. Being a CYP2C9 or VKORC1 polymorphism carrier is associated with a variation in doses required to achieve the therapeutic INR compared to non-carrier patients.

International Normalized Ratio and Mortality Risk in Acute Heart Failure and Nonvalvular Atrial Fibrillation Patients Receiving Vitamin K Antagonists

INTRODUCTION AND OBJECTIVES

Heart failure patients with nonvalvular atrial fibrillation (NVAF) on treatment with vitamin K antagonists (VKA) often have suboptimal international normalized ratio (INR) values. Our aim was to evaluate the association between INR values at admission due to acute heart failure and mortality risk during follow-up.

METHODS

In this observational study, we retrospectively assessed INR on admission in 1137 consecutive patients with acute heart failure and NVAF who were receiving VKA treatment. INR was categorized into optimal values (INR = 2-3, n = 210), subtherapeutic (INR < 2, n = 660), and supratherapeutic (INR > 3, n = 267). Because INR did not meet the proportional hazards assumption for mortality, restricted mean survival time differences were used to evaluate the association among INR categories and the risk of all-cause mortality.

RESULTS

During a median [interquartile range] follow-up of 2.15 years [0.71-4.29], 495 (43.5%) patients died. On multivariable analysis, both patients with subtherapeutic and supratherapeutic INR showed higher risks of all-cause mortality, as evidenced by their restricted mean survival time differences at 5 years' follow-up: -0.50; 95%CI, -0.77 to -0.23 years; P < .001; and -0.40; 95%CI, -0.70 to -0.11 years; P = .007, respectively, compared with INR 2-3.

CONCLUSIONS

In acute heart failure patients on treatment with VKA for NVAF, INR values out of normal range at admission were independently associated with a higher long-term mortality risk.

Patient-Specific Tailored Intervention Improves INR Time in Therapeutic Range and INR Variability in Heart Failure Patients

BACKGROUND

Many patients with heart failure need anticoagulants, including warfarin. Good control is particularly challenging in heart failure patients, with <60% of international normalized ratio (INR) measurements in the therapeutic range, thereby increasing the risk of complications. This study aimed to evaluate the effect of a patient-specific tailored intervention on anticoagulation control in patients with heart failure.

METHODS

Patients with heart failure taking warfarin therapy (n = 145) were randomized to either standard care or a 1-time intervention assessing potential risk factors for lability of INR, in which they received patient-specific instructions. Time in therapeutic range (TTR) using Rosendaal's linear model was assessed 3 months before and after the intervention.

RESULTS

The patient-tailored intervention significantly increased anticoagulation control. The median TTR levels before intervention were suboptimal in the interventional and control groups (53% vs 45%, P = .14). After intervention the median TTR increased significantly in the interventional group compared with the control group (80% [interquartile range, 62%-93%] vs 44% [29%-61%], P <.0001). The intervention resulted in a significant improvement in the interventional group before versus after intervention (53% vs 80%, P <.0001) but not in the control group (45% vs 44%, P = .95). The percentage of patients with a TTR ≥60%, considered therapeutic, was substantially higher in the interventional group: 79% versus 25% (P <.0001). The INR variability (standard deviation of each patient's INR measurements) decreased significantly in the interventional group, from 0.53 to 0.32 (P <.0001) after intervention but not in the control group.

CONCLUSIONS

Patient-specific tailored intervention significantly improves anticoagulation therapy in patients with heart failure.

Incidence and predictors of excessive warfarin anticoagulation in patients with atrial fibrillation-The EWA study

Vitamin K antagonist warfarin is widely used in clinical practice and excessive anticoagulation is a well-known complication of this therapy. Little is known about permanent and temporary predictors for severe overanticoagulation. The aim of this study was to investigate the occurrence and predicting factors for episodes with very high (≥9) international normalized ratio (INR) values in warfarin treated patients with atrial fibrillation (AF). Excessive Warfarin Anticoagulation (EWA) study screened all patients (n = 13618) in the Turku University Hospital region with an INR ≥2 between years 2003–2015. Patients using warfarin anticoagulation for AF with very high (≥9) INR values (EWA Group) were identified (n = 412 patients) and their characteristics were compared to a control group (n = 405) of AF patients with stable INR during long-term follow-up. Over 20% (n = 92) of the EWA patients had more than one event of very high INR and in 105 (25.5%) patients EWA led to a bleeding event. Of the several temporary and permanent EWA risk factors observed, strongest were excessive alcohol consumption in 9.6% of patients (OR 24.4, 95% CI 9.9–50.4, p<0.0001) and reduced renal function (OR 15.2, 95% CI 5.67–40.7, p<0.0001). Recent antibiotic or antifungal medication, recent hospitalization or outpatient clinic visit and the first 6 months of warfarin use were the most significant temporary risk factors for EWA. Excessive warfarin anticoagulation can be predicted with several permanent and temporary clinical risk factors, many of which are modifiable.

Pharmacogenetic-guided Warfarin Dosing Algorithm in African-Americans

We aim to develop warfarin dosing algorithm for African-Americans. We explored demographic, clinical, and genetic data from a previously collected cohort of 163 African-American patients with a stable warfarin dose. We explored 2 approaches to develop the algorithm: multiple linear regression and artificial neural network (ANN). The clinical significance of the 2 dosing algorithms was evaluated by calculating the percentage of patients whose predicted dose of warfarin was within 20% of the actual dose. Linear regression model and ANN model predicted the ideal dose in 52% and 48% of the patients, respectively. The mean absolute error using linear regression model was estimated to be 10.8 mg compared with 10.9 mg using ANN. Linear regression and ANN models identified several predictors of warfarin dose including age, weight, CYP2C9 genotype *1/*1, VKORC1 genotype, rs12777823 genotype, rs2108622 genotype, congestive heart failure, and amiodarone use. In conclusion, we developed a warfarin dosing algorithm for African-Americans. The proposed dosing algorithm has the potential to recommend warfarin doses that are close to the appropriate doses. The use of more sophisticated ANN approach did not result in improved predictive performance of the dosing algorithm except for patients of a dose of ≥49 mg/wk.

Effect of diseases on response to vitamin K antagonists

INTRODUCTION

The purpose of this review article is to summarize the literature on diseases that are documented to have an effect on response to warfarin and other VKAs.

METHODS

We searched the English literature from 1946 to September 2015 via PubMed, EMBASE, and Scopus for the effect of diseases on response vitamin K antagonists including warfarin, acenocoumarol, phenprocoumon, and fluindione.

DISCUSSION

Among many factors modifying response to VKAs, several disease states are clinically relevant. Liver disease, hyperthyroidism, and CKD are well documented to increase response to VKAs. Decompensated heart failure, fever, and diarrhea may also elevate response to VKAs, but more study is needed. Hypothyroidism is associated with decreased effect of VKAs, and obese patients will likely require higher initial doses of VKAs.

CONCLUSION

In order to minimize risks with VKAs while ensuring efficacy, clinicians must be aware of the effect of disease states when prescribing these oral anticoagulants.

Predicting outcomes among patients with atrial fibrillation and heart failure receiving anticoagulation with warfarin

Among patients receiving oral anticoagulation for atrial fibrillation (AF), heart failure (HF) is associated with poor anticoagulation control. However, it is not known which patients with heart failure are at greatest risk of adverse outcomes. We evaluated 62,156 Veterans Health Administration (VA) patients receiving warfarin for AF between 10/1/06-9/30/08 using merged VA-Medicare dataset. We predicted time in therapeutic range (TTR) and rates of adverse events by categorising patients into those with 0, 1, 2, or 3+ of five putative markers of HF severity such as aspartate aminotransferase (AST)> 80 U/l, alkaline phosphatase> 150 U/l, serum sodium< 130 mEq/l, any receipt of metolazone, and any inpatient admission for HF exacerbation. These risk categories predicted TTR: patients without HF (referent) had a mean TTR of 65.0 %, while HF patients with 0, 1, 2, 3 or more markers had mean TTRs of 62.2 %, 57.2 %, 53.5 %, and 50.7 %, respectively (p< 0.001). These categories also discriminated for major haemorrhage well; compared to patients without HF, HF patients with increasing severity had hazard ratios of 1.84, 3.06, 3.52 and 5.14 respectively (p< 0.001). However, although patients with HF had an elevated hazard for bleeding compared to those without HF, these categories did not effectively discriminate risk of ischaemic stroke across HF. In conclusion, we developed a HF severity model using easily available clinical characteristics that performed well to risk-stratify patients with HF who are receiving anticoagulation for AF with regard to major haemorrhage.

Anticoagulation versus placebo for heart failure in sinus rhythm

BACKGROUND

Patients with chronic heart failure (heart failure) are at risk of thromboembolic events, including stroke, pulmonary embolism and peripheral arterial embolism, whilst coronary ischaemic events also contribute to the progression of heart failure. Long-term oral anticoagulation is established in certain patient groups, including patients with heart failure and atrial fibrillation, but there is wide variation in the indications and use of oral anticoagulation in the broader heart failure population.

OBJECTIVES

To determine whether long-term oral anticoagulation reduces total deaths, cardiovascular deaths and major thromboembolic events in patients with heart failure.

SEARCH METHODS

We updated the searches in June 2030 in the electronic databases CENTRAL (Issue 6, 2013) in The Cochrane Library, MEDLINE (OVID, 1946 to June week 1 2013) and EMBASE (OVID, 1980 to 2013 week 23). Reference lists of papers and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors were contacted to obtain further data. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing oral anticoagulants with placebo in adults with heart failure, and with treatment duration at least one month. Non-randomised studies were also included for assessing side effects. Inclusion decisions were made in duplicate and any disagreement between review authors was resolved by discussion or a third party.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and assessed the risks and benefits of antithrombotic therapy using relative measures of effects, such as odds ratio, accompanied by the 95% confidence intervals.

MAIN RESULTS

Two RCTs were identified. One compared warfarin, aspirin and no antithrombotic therapy and the second compared warfarin with placebo in patients with idiopathic dilated cardiomyopathy. Three small prospective controlled studies of warfarin in heart failure were also identified, but they were over 50 years old with methods not considered reliable by modern standards. In both WASH 2004 and HELAS 2006, there were no significant differences in the incidence of myocardial infarction, non-fatal stroke and death between patients taking oral anticoagulation and those taking placebo. Four retrospective non-randomised cohort analyses and four observational studies of oral anticoagulation in heart failure included differing populations of heart failure patients and reported contradictory results.

AUTHORS' CONCLUSIONS

Based on the two major randomised trials (HELAS 2006; WASH 2004), there is no convincing evidence that oral anticoagulant therapy modifies mortality or vascular events in patients with heart failure and sinus rhythm. Although oral anticoagulation is indicated in certain groups of patients with heart failure (for example those with atrial fibrillation), the available data does not support the routine use of anticoagulation in heart failure patients who remain in sinus rhythm.

Spontaneous and non-spontaneous bleeding complications in patients with oral vitamin K antagonist therapy

PURPOSE

The aim of the study was to evaluate potential differences between patients with spontaneous and non-spontaneous bleeding episodes during treatment with vitamin K antagonists which mainly resulted in compartment syndromes.

METHODS

The population in this study comprised 116 patients who suffered at least one bleeding complication which required surgical treatment during therapy with an oral vitamin K antagonist. The patients were treated between September 2001 and July 2008.

RESULTS

Significant differences were observed between the two patient groups with regard to the presence of renal failure, arterial hypertension, and diabetes mellitus, which occurred more frequently in patients with spontaneous bleeding. Also, significantly more patients with spontaneous bleedings developed compartment syndrome that needed emergency operation. Overall mortality was 9.6 %, was associated with multiorgan failure in all patients, and was not different between the two patient groups.

CONCLUSIONS

The identification of high-risk patients before treatment with an oral vitamin K antagonist is of major importance. The existence of over-anticoagulation syndrome and compartment syndrome is associated with significant mortality and morbidity and should not be underestimated.

Applications of CYP450 testing in the clinical setting

Interindividual variability in drug response is a major clinical problem. Polymedication and genetic polymorphisms modulating drug-metabolising enzyme activities (cytochromes P450, CYP) are identified sources of variability in drug responses. We present here the relevant data on the clinical impact of the major CYP polymorphisms (CYP2D6, CYP2C19 and CYP2C9) on drug therapy where genotyping and phenotyping may be considered, and the guidelines developed when available. CYP2D6 is responsible for the oxidative metabolism of up to 25% of commonly prescribed drugs such as antidepressants, antipsychotics, opioids, antiarrythmics and tamoxifen. The ultrarapid metaboliser (UM) phenotype is recognised as a cause of therapeutic inefficacy of antidepressant, whereas an increased risk of toxicity has been reported in poor metabolisers (PMs) with several psychotropics (desipramine, venlafaxine, amitriptyline, haloperidol). CYP2D6 polymorphism influences the analgesic response to prodrug opioids (codeine, tramadol and oxycodone). In PMs for CYP2D6, reduced analgesic effects have been observed, whereas in UMs cases of life-threatening toxicity have been reported with tramadol and codeine. CYP2D6 PM phenotype has been associated with an increased risk of toxicity of metoprolol, timolol, carvedilol and propafenone. Although conflicting results have been reported regarding the association between CYP2D6 genotype and tamoxifen effects, CYP2D6 genotyping may be useful in selecting adjuvant hormonal therapy in postmenopausal women. CYP2C19 is responsible for metabolising clopidogrel, proton pump inhibitors (PPIs) and some antidepressants. Carriers of CYP2C19 variant alleles exhibit a reduced capacity to produce the active metabolite of clopidogrel, and are at increased risk of adverse cardiovascular events. For PPIs, it has been shown that the mean intragastric pH values and the Helicobacter pylori eradication rates were higher in carriers of CYP2C19 variant alleles. CYP2C19 is involved in the metabolism of several antidepressants. As a result of an increased risk of adverse effects in CYP2C19 PMs, dose reductions are recommended for some agents (imipramine, sertraline). CYP2C9 is responsible for metabolising vitamin K antagonists (VKAs), non-steroidal anti-inflammatory drugs (NSAIDs), sulfonylureas, angiotensin II receptor antagonists and phenytoin. For VKAs, CYP2C9 polymorphism has been associated with lower doses, longer time to reach treatment stability and higher frequencies of supratherapeutic international normalised ratios (INRs). Prescribing algorithms are available in order to adapt dosing to genotype. Although the existing data are controversial, some studies have suggested an increased risk of NSAID-associated gastrointestinal bleeding in carriers of CYP2C9 variant alleles. A relationship between CYP2C9 polymorphisms and the pharmacokinetics of sulfonylureas and angiotensin II receptor antagonists has also been observed. The clinical impact in terms of hypoglycaemia and blood pressure was, however, modest. Finally, homozygous and heterozygous carriers of CYP2C9 variant alleles require lower doses of phenytoin to reach therapeutic plasma concentrations, and are at increased risk of toxicity. New diagnostic techniques made safer and easier should allow quicker diagnosis of metabolic variations. Genotyping and phenotyping may therefore be considered where dosing guidelines according to CYP genotype have been published, and help identify the right molecule for the right patient.

Lifetime risk for heart failure among white and black Americans: cardiovascular lifetime risk pooling project

OBJECTIVES

This study sought to estimate lifetime risk for heart failure (HF) by sex and race.

BACKGROUND

Prior estimates of lifetime risk for developing HF range from 20% to 33% in predominantly white cohorts. Short-term risks for HF appear higher for blacks than whites, but only limited comparisons of lifetime risk for HF have been made.

METHODS

Using public-release and internal datasets from National Heart, Lung, and Blood Institute-sponsored cohorts, we estimated lifetime risks for developing HF to age 95 years, with death free of HF as the competing event, among participants in the CHA (Chicago Heart Association Detection Project in Industry), ARIC (Atherosclerosis Risk in Communities), and CHS (Cardiovascular Health Study) cohorts.

RESULTS

There were 39,578 participants (33,652 [85%] white; 5,926 [15%] black) followed for 716,976 person-years; 5,983 participants developed HF. At age 45 years, lifetime risks for HF through age 95 years in CHA and CHS were 30% to 42% in white men, 20% to 29% in black men, 32% to 39% in white women, and 24% to 46% in black women. Results for ARIC demonstrated similar lifetime risks for HF in blacks and whites through age 75 years (limit of follow-up). Lifetime risk for HF was higher with higher blood pressure and body mass index at all ages in both blacks and whites, and did not diminish substantially with advancing index age.

CONCLUSIONS

These are among the first data to compare lifetime risks for HF between blacks and whites. Lifetime risks for HF are high and appear similar for black and white women, yet are somewhat lower for black compared with white men due to competing risks.

Anticoagulation versus placebo for heart failure in sinus rhythm

BACKGROUND

Patients with chronic heart failure (heart failure) are at risk of thromboembolic events, including stroke, pulmonary embolism and peripheral arterial embolism, whilst coronary ischaemic events also contribute to the progression of heart failure. Long-term oral anticoagulation is established in certain groups, including patients with heart failure and atrial fibrillation, but there is wide variation in the indications and use of oral anticoagulation in the broader heart failure population.

OBJECTIVES

To determine whether long-term oral anticoagulation reduces total deaths and/or major thromboembolic events in patients with heart failure.

SEARCH METHODS

We updated the searches in February 2010 on CENTRAL on The Cochrane Library (Issue 1, 2010), MEDLINE (2000 to February 2010) and EMBASE (1998 to February 2010). Reference lists of papers and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors were contacted to obtain further data. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing oral anticoagulants with placebo in adults with heart failure, and with treatment duration at least one month. Non-randomised studies were also included for assessing side-effects. Inclusion decisions were duplicated, disagreement resolved by discussion or a third party.

DATA COLLECTION AND ANALYSIS

Four review authors independently assessed trials for inclusion and assessed the risks and benefits from antithrombotic therapy using relative measures of effects, such as odds ratio, accompanied with 95% confidence intervals.

MAIN RESULTS

Two RCTs were identified. One compared warfarin, aspirin and no antithrombotic therapy and the second compared warfarin with placebo in patients with idiopathic dilated cardiomyopathy. Three small prospective controlled studies of warfarin in heart failure were also identified, but were over 50 years old with methods not considered reliable by modern standards. In both WASH 2004 and HELAS 2006, there were no significant differences in the incidence of myocardial infarction, non-fatal stroke and death between patients taking oral anticoagulation and placebo. Four retrospective non-randomised cohort analyses and four observational studies of oral anticoagulation in heart failure included differing populations of heart failure patients and reported contradictory results.

AUTHORS' CONCLUSIONS

Based on the two major randomised trials (HELAS 2006; WASH 2004), there is no convincing evidence that oral anticoagulant therapy modifies mortality or vascular events in patients with heart failure and sinus rhythm. Although oral anticoagulation is indicated in certain groups of patients with heart failure (for example atrial fibrillation), the data available does not support its routine use in heart failure patients who remain in sinus rhythm. A large randomised trial of warfarin in heart failure patients in sinus rhythm is currently in progress and data from this trial will be a useful addition to this topic.

[Bleeding, the Achilles' heel in patients treated with anticoagulants. Approach in patients with atrial fibrillation]

Bleeding is always the Achilles' heel of all antithrombotic therapy, being unthinkable to use this type of therapy ignoring the complications that it may arise. The bleeding risk raises very particular problems, namely how to predict it and how to manage it. The withdrawal of antithrombotic drugs and transfusion are two important practical problems, involving clinical decisions that are generally very difficult. The new oral anticoagulants pose new problems. If on the one hand its bleeding risk appears to be less, specially in what concerns intracranial bleeding and potentially life-threatening bleeding, on the other hand the lack of an antidote or the lack of a quick and effective laboratory test to evaluate its efficacy, are arguments used by the critics. The risk of bleeding is conditioned by several factors, among them old age. The elderly patient is, by definition, the patient that can bleed more but also the one that, due to its ischemic risk, can reap more benefit. In this paper some of the tools used to predict the risk of bleeding and its clinical impact are also presented.

Effect of oral diuretics on chronic warfarin therapy: a retrospective study

BACKGROUND

Limited clinical documentation is suggestive of a drug interaction between warfarin and diuretics.

OBJECTIVE

To evaluate the effect on international normalized ratio (INR) when a daily oral diuretic is started or increased in patients on chronic stable warfarin therapy.

METHODS

The medical records of all active patients of two hospital-based anticoagulation clinics were retrospectively reviewed to identify patients who were started on or received a dose increase of a daily oral diuretic while on stable warfarin therapy. The primary endpoint was the mean difference between an INR recorded within 30 days prior to the diuretic initiation (pre-INR) and an INR recorded within 30 days after diuretic initiation (post-INR).

RESULTS

A total of 1254 patient charts were screened and a total of 123 patients met the study criteria. The mean difference in pre-INR and post-INR was 0.09 (95% CI -0.03 to 0.21, p = 0.12). Post-INR values were outside of the patient's therapeutic range in 39 patients (32%), but no major bleeding or thromboembolic events were reported.

CONCLUSION

Based on this retrospective study, diuretics did not result in a significant change in the INR in patients on stable warfarin therapy.

The Rotterdam Study: 2012 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Effect of heart failure exacerbations on anticoagulation: a prospective, observational, pilot cohort study

BACKGROUND

Some studies have suggested that heart failure (HF) is associated with excessive anticoagulation, but definitive data or data showing causation do not exist. Knowledge of risk factors for excessive anticoagulation is critical to manage warfarin therapy safely.

OBJECTIVE

This study characterized the relation between HF-associated hypervolemia and excessive anticoagulation in patients with HF taking chronic warfarin therapy.

METHODS

This was a prospective, observational pilot study conducted in a university-based HF clinic. Patients aged 18 to 85 years with HF and taking warfarin were enrolled and were observed for episodes of hypervolemia. Hypervolemia was determined based on multiple clinical factors, including patient-reported symptoms and physical examination. Anticoagulation was assessed longitudinally per standard of care by measurement of the international normalized ratio (INR). A chi(2) analysis was used to determine whether hypervolemia was associated with an increased risk of excessive anticoagulation. Paired and unpaired t tests were used for ad hoc analyses.

RESULTS

Forty patients with 41 HF episodes who were taking warfarin were enrolled between December 2003 and July 2007. Mean (SD) age was 67.2 (11.1) years and mean weight was 218.5 (62.8) pounds; 29 patients (72.5%) were men and 34 (85.0%) were white. Most had systolic dysfunction (n = 26; 65.0%) and were taking warfarin for atrial fibrillation (n = 33; 82.5%); the mean weekly warfarin dose was 30.8 (17.5) mg. There were 41 evaluable hypervolemia episodes over a mean follow-up of 14.5 (9.0) months. The mean INR change during hypervolemia was -0.02 (0.82) INR unit (P = NS vs baseline). No association was found between hypervolemia episodes and INR increases of > or =50% (P = NS); the results remained nonsignificant for both diastolic and systolic HF when analyzed separately. There was no significant change from baseline INR between patients classified with mild, moderate, or severe hypervolemia or between patients classified according to New York Heart Association (NYHA) functional class (all, P = NS). Patients with NYHA class III had a lower weekly warfarin dose than those with NYHA class II (25.73 vs 31.75 mg; P < 0.01).

CONCLUSION

Mild hypervolemia did not appear to be related to excessive anticoagulation in these patients with HF taking chronic warfarin therapy.

Patient Factors That Influence Warfarin Dose Response

Warfarin has long been the mainstay of oral anticoagulation therapy for the treatment and prevention of venous and arterial thrombosis. The narrow therapeutic index of warfarin, and the complex number of factors that influence international normalized ratio (INR) response, makes optimization of warfarin therapy challenging. Determination of the appropriate warfarin dose during initiation and maintenance therapy requires an understanding of patient factors that influence dose response: age, body weight, nutritional status, acute and chronic disease states, and changes in concomitant drug therapy and diet. This review will examine specific clinical factors that can affect the pharmacokinetics and pharmacodynamics of warfarin, as well as the role of pharmacogenetics in optimizing warfarin therapy.

Coagulopathy in critically ill patients: part 2-soluble clotting factors and hemostatic testing

This manuscript provides an overview of how to interpret in vitro clotting studies and how to select studies to evaluate patients with bleeding disorders in the ICU. It provides a practical approach to understanding the complex subject of clotting factor abnormalities, including the most common problems of preanalytical error and anticoagulation therapy. Limitations and pitfalls of diagnostic testing are highlighted.

Epidemiology of subtherapeutic anticoagulation in the United States

BACKGROUND

Low international normalized ratio (INR; <or=1.5) increases risk for thromboembolism. However, little is known about the epidemiology of low INR.

METHODS AND RESULTS

We prospectively collected data from 47 community-based clinics located throughout the United States from 2000 to 2002. We examined risk factors for low INR (<or=1.5), reasons given in the medical record for low INR, and proportion of thromboembolic events that occurred during periods of low INR. Of the 4489 patients in our database, 1540 (34%) had at least 1 low INR. Compared with men, women had an increased incidence of low INR (adjusted incidence rate ratio, 1.44; P<0.001). Compared with patients anticoagulated for atrial fibrillation, patients anticoagulated for venous thromboembolism had an increased incidence of low INR (adjusted incidence rate ratio, 1.48; P<0.001). The 5 most common reasons for low INR were nonadherence (17%), interruptions for procedures (16%), recent dose reductions (15%), no reason apparent after questioning (15%), and second or greater consecutive low INR (13%). A total of 21.8% of thromboembolic events (95% CI, 12.2 to 35.4%) occurred during periods of low INR; 58% of these events were related to an interruption of warfarin therapy.

CONCLUSIONS

In this cohort of patients receiving warfarin, more than 1 in 5 thromboembolic events occurred during a period of low INR. Women and patients anticoagulated for venous thromboembolism were particularly likely to experience low INR. Improving adherence, minimizing interruptions of therapy, and addressing low INR more promptly could reduce the risk of low INR.

Anticoagulation in patients with heart failure and normal sinus rhythm

PURPOSE

The evidence evaluating the risk of thrombosis and the efficacy and risk of anticoagulation in patients with systolic heart failure (HF) and normal sinus rhythm is reviewed.

SUMMARY

Although a subject of investigation for over 50 years, use of anticoagulation in patients with HF remains an area of controversy and clinical debate. While early studies reported variable thromboembolism rates in HF (1.9-42.4 events per 100 patient years), the annual rate from larger and more recent trials ranged from 1% to 3%. The trials evaluating the role of oral anticoagulants to reduce thromboembolism and mortality outcomes in patients with a reduced ejection fraction (EF) have provided ambiguous results. Early studies and post hoc analyses of large clinical trials have demonstrated a reduction in thromboembolic events, risk of stroke, and mortality. In contrast, recent underpowered prospective controlled studies found no benefit in the use of warfarin in patients with systolic HF and normal sinus rhythm. The low-to-moderate risk of thromboembolism in patients with HF and the questionable benefit of anticoagulation need to be weighed against the potential for hemorrhagic complications caused by this therapy. The available data collectively suggest that the risk of using warfarin in patients with reduced EF may outweigh any possible benefit, if one exists at all.

CONCLUSION

Anticoagulation therapy in patients with HF and normal sinus rhythm is not supported by the limited evidence. The benefits of anticoagulation in such patients may not compensate for the relatively high risk of major bleeding caused by the treatment.

Randomized Trial of Warfarin, Aspirin, and Clopidogrel in Patients With Chronic Heart Failure

Background— Chronic heart failure remains a major cause of mortality and morbidity. The role of antithrombotic therapy in patients with chronic heart failure has long been debated. The objective of this study was to determine the optimal antithrombotic agent for heart failure patients with reduced ejection fractions who are in sinus rhythm.

Methods and Results— This prospective, randomized clinical trial of open-label warfarin (target international normalized ratio of 2.5 to 3.0) and double-blind treatment with either aspirin (162 mg once daily) or clopidogrel (75 mg once daily) had a 30-month enrollment period and a minimum of 12 months of treatment. We enrolled 1587 men and women ≥18 years of age with symptomatic heart failure for at least 3 months who were in sinus rhythm and had left ventricular ejection fraction of ≤35%. The primary outcome was the time to first occurrence of death, nonfatal myocardial infarction, or nonfatal stroke. For the primary composite end point, the hazard ratios were as follows: for warfarin versus aspirin, 0.98 (95% CI, 0.86 to 1.12; P =0.77); for clopidogrel versus aspirin, 1.08 (95% CI, 0.83 to 1.40; P =0.57); and for warfarin versus clopidogrel, 0.89 (95% CI, 0.68 to 1.16; P =0.39). Warfarin was associated with fewer nonfatal strokes than aspirin or clopidogrel. Hospitalization for worsening heart failure occurred in 116 (22.2%), 97 (18.5%), and 89 (16.5%) patients treated with aspirin, clopidogrel, and warfarin, respectively ( P =0.02 for warfarin versus aspirin).

Conclusion— The primary outcome measure and the mortality data do not support the primary hypotheses that warfarin is superior to aspirin and that clopidogrel is superior to aspirin.

The Rotterdam Study: 2010 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

The Rotterdam Study: objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in the Netherlands. The study targets cardiovascular, neurological, ophthalmological and endocrine diseases. As of 2008 about 15,000 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in some 600 research articles and reports (see http://www.epib.nl/rotterdamstudy). This article gives the reasons for the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

The effect of hospitalization on oral anticoagulation control: A population-based study

BACKGROUND

For patients taking oral anticoagulants (OAC), the proportion of time spent in the therapeutic range is strongly associated with bleeding and thromboembolic risk. Previous studies examining OAC control may not generalize because the patient population was select or INR capture was incomplete.

OBJECTIVES

Measure OAC control for an entire population of elderly people and determine patient factors associated with OAC control.

PATIENTS

People in Eastern Ontario without valve replacement aged 65 years or greater who were treated with warfarin between 1 September 1999 and 1 September 2000.

DESIGN

Retrospective cohort study using population-based administrative databases. OAC control was measured as the proportion of days in therapeutic range (PDTR), defined as the number days with the INR between 2 and 3 divided by total number of days observation. Linear interpolation was used to determine INR levels between measures. Negative binomial regression was used to identify patient factors independently associated with PDTR. We also determined which factors were associated with proportion of days with a critically low (<1.5) or critically high (>/=5) INR.

RESULTS

7179 people were followed for a total of 3238 years. 15% of people were hospitalized during the study. Overall, PDTR was 59.2% (95% CI 59.1%-59.2%). Independent of all other significant factors, hospitalization was associated with a 15% decrease in the PDTR 15% (rate ratio 0.85, 95% CI 0.83-0.87). Hospitalization was also independently associated with greater proportion of time with a critically low INR (rate ratio 1.68, 95% CI 1.51-1.88) and a critically high INR (1.70, 95% CI 1.38-2.08).

CONCLUSIONS

Elderly people in eastern Ontario taking warfarin were therapeutic 59.2% of the time. Independent of other patient factors, patients who are hospitalized have the greatest risk of poor anticoagulation control. Control for anticoagulated patients who get hospitalized should be reviewed to determine if and how it could be improved.

VKORC1 and CYP2C9 genotypes and phenprocoumon anticoagulation status: interaction between both genotypes affects dose requirement

In a prospective follow-up study of the effects of VKORC1 and CYP2C9 genotypes on the anticoagulation status of patients, we assessed the CYP2C9 and the VKORC1 C1173T genotypes of patients during the initial 6 months of phenprocoumon treatment. We used linear regression models and Cox proportional hazard models to determine the effects of the VKORC1 and CYP2C9 genotypes on phenprocoumon dose requirements, overanticoagulation, and time to achieve stability. Allele frequencies of interest within the cohort (N=281) were 40.8% VKORC1 T-1173, 12.8% CYP2C9*2, and 6.9% CYP2C9*3. In patients with the VKORC1 CC genotype, carriers of a CYP2C9 polymorphism needed dosages that were nearly 30% lower than those for CYP2C9*1/*1 patients (P<0.001). In patients with a VKORC1 polymorphism, differences between carriers of a CYP2C9 polymorphism and CYP2C9*1/*1 were far smaller and largely not statistically significant. A larger part of the variability in dose requirement was explained by the VKORC1 genotype than by the CYP2C9 genotype (28.7% and 7.2%, respectively). Carriers of a combination of a CYP2C9 polymorphism and a VKORC1 polymorphism had a strongly increased risk of severe overanticoagulation (hazard ratio (HR) 7.20, P=0.002). Only carriers of a CYP2C9*2 allele had a decreased chance to achieve stability compared to CYP2C9*1/*1 patients (HR 0.61, P=0.004). In conclusion, the VKORC1 genotype modifies the effect of the CYP2C9 genotype on phenprocoumon dose requirements. A combination of polymorphisms of both genotypes is associated with a strongly increased risk of overanticoagulation, whereas delayed stabilization is mainly associated with the CYP2C9 genotype.

Effect of Study Setting on Anticoagulation Control

BACKGROUND

For patients receiving therapy with oral anticoagulants (OACs), the proportion of time spent in the therapeutic range (ie, anticoagulation control) is strongly associated with bleeding and thromboembolic risk. The effect of study-level factors, especially study setting, on anticoagulation control is unknown.

OBJECTIVES

Describe anticoagulation control achieved in the published literature. We also used metaregressive techniques to determine which study-level factors significantly influenced anticoagulation control.

STUDIES

All published randomized or cohort studies that measured international normalized ratios (INRs) serially in anticoagulated patients and reported the proportion of time between INRs ranging from 1.8 to 2.0 and 3.0 to 3.5.

RESULTS

We identified 67 studies with 123 patient groups having 50,208 patients followed for a total of 57,154.7 patient-years. A total of 68.3% of groups were from anticoagulation clinics, 7.3% were from clinical trials, and 24.4% were from community practices. Overall, patients were therapeutic 63.6% of time (95% confidence interval [CI], 61.6 to 65.6). In the metaregression model, study setting had the greatest effect on anticoagulation control with studies in community practices having significantly lower control than either anticoagulation clinics or clinical trials (-12.2%; 95% CI, -19.5 to -4.8; p < 0.0001). Self-management was associated with a significant improvement of time spent in the therapeutic range (+7.0%; 95% CI, 0.7 to 13.3; p = 0.03).

CONCLUSIONS

Patients who have received anticoagulation therapy spend a significant proportion of their time with an INR out of the therapeutic range. Patients from community practices showed significantly worse anticoagulation control than those from anticoagulation clinics or clinical trials. This should be considered when interpreting the results of, and generalizing from, studies involving OACs.

Anticoagulation for heart failure in sinus rhythm

BACKGROUND

Patients with chronic heart failure (heart failure) are at risk of thromboembolic events, including stroke, pulmonary embolism and peripheral arterial embolism, whilst coronary ischaemic events also contribute to the progression of heart failure. Long-term oral anticoagulation is established in certain groups, including patients with heart failure and atrial fibrillation but there is wide variation in the indications and use of oral anticoagulation in the broader heart failure population.

OBJECTIVES

To determine whether long-term oral anticoagulation reduces total deaths and/or major thromboembolic events in patients with heart failure, when compared to placebo.

SEARCH STRATEGY

Reference lists of papers resulting from this search, electronic database searching (MEDLINE, EMBASE, DARE), and abstracts from national and international cardiovascular meetings were studied to identify unpublished studies. Relevant authors of these studies were contacted to obtain further data.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing oral anticoagulants with control or placebo. Non-randomised studies were included as they may help in assessing side-effects. Duration of treatment at least 1 month, adults with heart failure due to any underlying cause. Inclusion decisions were duplicated, disagreement resolved by discussion or a third party.

DATA COLLECTION AND ANALYSIS

Data were collected by two reviewers independently and where appropriate data from RCTs were meta-analysed.

MAIN RESULTS

One recent pilot RCT compared warfarin, aspirin and no antithrombotic therapy, but no definitive data have yet been published. Three small prospective studies of warfarin in heart failure were also identified, but were over 50 years old with methods not considered reliable by modern standards. Anticoagulation was more efficacious than control for the reduction of all cause death (odds ratio 0.64 95% CI 0.45,0.90) and the reduction of cardiovascular events (0.26 95% CI 0.16, 0.43). Four retrospective non-randomised cohort analyses and three small observational studies of oral anticoagulation in heart failure included differing populations of heart failure patients and reported contradictory results.

REVIEWER'S CONCLUSIONS

Evidence from the RCTs and observational studies found a reduction in mortality and cardiovascular events with anticoagulants compared to control. This evidence needs to be interpreted with caution. Although oral anticoagulation is indicated in certain groups of patients with heart failure (eg atrial fibrillation), the data available does not support its routine use in heart failure patients who remain in sinus rhythm. A large randomised trial of warfarin in heart failure patients in sinus rhythm is currently in progress data from which will be useful addition to this story.