We investigated the prevalence of prior myocardial infarction (MI) and incidence of ischaemic cardiovascular (CV) events among atrial fibrillation (AF) patients.
Methods and results
In ROCKET AF, 14 264 patients with nonvalvular AF were randomized to rivaroxaban or warfarin. The key efficacy outcome for these analyses was CV death, MI, and unstable angina (UA). This pre-specified analysis was performed on patients while on treatment. Rates are per 100 patient-years. Overall, 2468 (17%) patients had prior MI at enrollment. Compared with patients without prior MI, these patients were more likely to be male (75 vs. 57%), on aspirin at baseline (47 vs. 34%), have prior congestive heart failure (78 vs. 59%), diabetes (47 vs. 39%), hypertension (94 vs. 90%), higher mean CHADS2 score (3.64 vs. 3.43), and fewer prior strokes or transient ischaemic attacks (46 vs. 54%). CV death, MI, or UA rates tended to be lower in patients assigned rivaroxaban compared with warfarin [2.70 vs. 3.15; hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.73–1.00; P = 0.0509]. CV death, MI, or UA rates were higher in those with prior MI compared with no prior MI (6.68 vs. 2.19; HR 3.04, 95% CI 2.59–3.56) with consistent results for CV death, MI, or UA for rivaroxaban compared with warfarin in prior MI compared with no prior MI (P interaction = 0.10).
Prior MI was common and associated with substantial risk for subsequent cardiac events. Patients with prior MI assigned rivaroxaban compared with warfarin had a non-significant 14% reduction of ischaemic cardiac events.
Atrial fibrillation; Myocardial infarction; Coronary artery disease; Outcomes; Factor Xa; Rivaroxaban; Warfarin
During long-term anticoagulation in atrial fibrillation, temporary interruptions (TIs) of therapy are common, but the relationship between patient outcomes and TIs has not been well studied. We sought to determine reasons for TI, the characteristics of patients undergoing TI, and the relationship between anticoagulant and outcomes among patients with TI.
Methods and Results
In the Rivaroxaban Once Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF), a randomized, double-blind, double-dummy study of rivaroxaban and warfarin in nonvalvular atrial fibrillation, baseline characteristics, management, and outcomes, including stroke, non–central nervous system systemic embolism, death, myocardial infarction, and bleeding, were reported in participants who experienced TI (3–30 days) for any reason. The at-risk period for outcomes associated with TI was from TI start to 30 days after resumption of study drug. In 14 236 participants who received at least 1 dose of study drug, 4692 (33%) experienced TI. Participants with TI were similar to the overall ROCKET AF population in regard to baseline clinical characteristics. Only 6% (n=483) of TI incidences involved bridging therapy. Stroke/systemic embolism rates during the at-risk period were similar in rivaroxaban-treated and warfarin-treated participants (0.30% versus 0.41% per 30 days; hazard ratio [confidence interval]=0.74 [0.36–1.50]; P=0.40). Risk of major bleeding during the at-risk period was also similar in rivaroxaban-treated and warfarin-treated participants (0.99% versus 0.79% per 30 days; hazard ratio [confidence interval]=1.26 [0.80–2.00]; P=0.32).
TI of oral anticoagulation is common and is associated with substantial stroke risks and bleeding risks that were similar among patients treated with rivaroxaban or warfarin. Further investigation is needed to determine the optimal management strategy in patients with atrial fibrillation requiring TI of anticoagulation.
Clinical Trial Registration
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00403767.
anticoagulation; atrial fibrillation; stroke
This study sought to report additional safety results from the ROCKET AF (Rivaroxaban Once-daily oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation).
The ROCKET AF trial demonstrated similar risks of stroke/systemic embolism and major/nonmajor clinically relevant bleeding (principal safety endpoint) with rivaroxaban and warfarin.
The risk of the principal safety and component bleeding endpoints with rivaroxaban versus warfarin were compared, and factors associated with major bleeding were examined in a multivariable model.
The principal safety endpoint was similar in the rivaroxaban and warfarin groups (14.9 vs. 14.5 events/100 patient-years; hazard ratio: 1.03; 95% confidence interval: 0.96 to 1.11). Major bleeding risk increased with age, but there were no differences between treatments in each age category (<65, 65 to 74, ≥75 years; pinteraction = 0.59). Compared with those without (n = 13,455), patients with a major bleed (n = 781) were more likely to be older, current/prior smokers, have prior gastrointestinal (GI) bleeding, mild anemia, and a lower calculated creatinine clearance and less likely to be female or have a prior stroke/transient ischemic attack. Increasing age, baseline diastolic blood pressure (DBP) ≥90 mm Hg, history of chronic obstructive pulmonary disease or GI bleeding, prior acetylsalicylic acid use, and anemia were independently associated with major bleeding risk; female sex and DBP <90 mm Hg were associated with a decreased risk.
Rivaroxaban and warfarin had similar risk for major/nonmajor clinically relevant bleeding. Age, sex, DBP, prior GI bleeding, prior acetylsalicylic acid use, and anemia were associated with the risk of major bleeding. (An Efficacy and Safety Study of Rivaroxaban With Warfarin for the Prevention of Stroke and Non-Central Nervous System Systemic Embolism in Patients With Non-Valvular Atrial Fibrillation: NCT00403767)
anticoagulants; atrial fibrillation; hemorrhage
Independent data monitoring committees (IDMCs) were introduced to monitor patient safety and study conduct in randomized clinical trials (RCTs), but certain challenges regarding the utilization of IDMCs have developed. First, the roles and responsibilities of IDMCs are expanding, perhaps due to increasing trial complexity and heterogeneity regarding medical, ethical, legal, regulatory, and financial issues. Second, no standard for IDMC operating procedures exists, and there is uncertainty about who should determine standards and whether standards should vary with trial size and design. Third, considerable variability in communication pathways exist across IDMC interfaces with regulatory agencies, academic coordinating centers, and sponsors. Finally, there has been a substantial increase in the number of RCTs using IDMCs, yet there is no set of qualifications to help guide the training and development of the next generation of IDMC members. Recently, an expert panel of representatives from government, industry, and academia assembled at the Duke Clinical Research Institute to address these challenges and to develop recommendations for the future utilization of IDMCs in RCTs.
The role of concomitant aspirin therapy in patients with atrial fibrillation (AF) receiving oral anticoagulation (OAC) is unclear. We assessed concomitant aspirin use and its association with clinical outcomes among AF patients treated with OAC.
Methods and Results
The Outcomes Registry for Better Informed Treatment (ORBIT) of Atrial Fibrillation registry enrolled 10,126 AF patients from 176 US practices from June, 2010 through August, 2011. The study population was limited to those on OAC (n=7,347).
Hierarchical multivariable logistic regression models were used to assess factors associated with concomitant aspirin therapy. Primary outcomes were 6-month bleeding, hospitalization, ischemic events, and mortality. Overall, 35% (n=2543) of AF patients on OAC also received aspirin (OAC+ASA). Patients receiving OAC+ASA were more likely male (66% vs. 53%, p<0.0001) and had more comorbid illness than those on OAC alone. Over one-third (39%) of OAC+ASA did not have a history of atherosclerotic disease, yet 17% had elevated ATRIA bleeding risk scores (≥5). Major bleeding (adjusted HR 1.53, 95% CI 1.20–1.96) and bleeding hospitalizations (adjusted HR 1.52, 95% CI 1.17–1.97) were significantly higher in those on OAC+ASA versus OAC alone. Rates of ischemic events were low.
Patients with AF receiving OAC are often treated with concomitant aspirin, even when they do not have cardiovascular disease. Use of OAC+ASA was associated with significantly increased risk for bleeding, emphasizing the need to carefully determine if and when the benefits of concomitant aspirin outweigh the risks in AF patients already on OAC.
atrial fibrillation; anticoagulants; aspirin; hemorrhage; outcomes research
Clinical trials traditionally use time‐to‐first‐event analysis embedded within the composite endpoint of cardiovascular death (CVD), myocardial infarction (MI), or stroke. However, many patients have >1 event, and this approach may not reflect overall experience. We addressed this by analyzing all cardiovascular events in TRACER.
Methods and Results
TRACER randomized 12 944 patients with non‐ST‐segment elevation acute coronary syndromes to placebo or to protease‐activated receptor 1 antagonist vorapaxar with a median follow‐up of 502 days (interquartile range, 349 to 667). Analysis of vorapaxar's effect on recurrent CVD, MI, or stroke was prespecified using the Wei, Lin, and Weissfeld approach. Vorapaxar did not reduce the first occurrence of the primary endpoint of CVD, MI, stroke, revascularization, or rehospitalization for recurrent ischemia, but reduced the secondary composite endpoint of CVD, MI, or stroke (14.7% vorapaxar vs. 16.4% placebo; hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.81 to 0.98; P=0.02; number needed to treat [NNT], 81). Recurrent secondary events occurred in 2.7% of patients. Vorapaxar reduced overall occurrences of ischemic events, first and subsequent (HR, 0.88; 95% CI, 0.80 to 0.98; P=0.02; NNT, 51). Also, there was a trend indicating that vorapaxar reduced the expanded endpoint, including revascularization and rehospitalization for recurrent ischemia (HR, 0.92; 95% CI, 0.84 to 1.01; P=0.09). Vorapaxar increased overall occurrences of moderate and severe Global Use of Strategies to Open Occluded Coronary Arteries bleeding (HR, 1.42; 95% CI, 1.21 to 1.66; P<0.001) and Thrombolysis in Myocardial Infarction clinically significant bleeding (HR, 1.550; 95% CI, 1.403 to 1.713; P<0.001).
Vorapaxar reduced overall occurrences of ischemic events, but increased bleeding. These exploratory findings broaden our understanding of vorapaxar's potential and expand our understanding of the value of capturing recurrent events.
Clinical Trial Registration
URL: ClinicalTrials.gov. Unique identifier: NCT00527943.
acute coronary syndromes; recurrent events; vorapaxar
This study sought to determine if there is an association between bleed location and clinical outcomes in acute coronary syndromes (ACS) patients.
The prognostic significance of bleeding location among ACS patients undergoing cardiac catheterization is not well known.
We analyzed in-hospital bleeding events among 9,978 patients randomized in the SYNERGY (Superior Yield of the New Strategy of Enoxaparin, Revascularization, and Glycoprotein IIb/IIIa Inhibitors) study. Bleeding events were categorized by location as access site, systemic, surgical, or superficial, and severity was graded using the GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) definition. We assessed the association of each bleeding location and severity with 6-month risk of death or myocardial infarction using a multicovariate-adjusted Cox proportional hazard model.
A total of 4,900 bleeding events were identified among 3,694 ACS patients with in-hospital bleeding. Among 4,679 GUSTO mild/moderate bleeding events, only surgical and systemic bleeds were associated with an increased risk of 6-month death or myocardial infarction (adjusted hazard ratio [HR]: 2.52 [95% confidence interval (CI): 2.16 to 2.94, and 1.40 [95% CI: 1.16 to 1.69], respectively). Mild/moderate superficial and access-site bleeds were not associated with downstream risk (adjusted HR: 1.17 [95% CI: 0.97 to 1.40], and 0.96 [95% CI: 0.82 to 1.12], respectively). Among 221 GUSTO severe bleeds, surgical bleeds were associated with the highest risk (HR: 5.27 [95% CI: 3.80 to 7.29]), followed by systemic (HR: 4.48 [95% CI: 2.98 to 6.72]), and finally access-site bleeds (HR: 3.57 [95% CI: 2.35 to 5.40]).
Among ACS patients who develop in-hospital bleeding, systemic and surgical bleeding are associated with the highest risks of adverse outcomes regardless of bleeding severity. Although the most frequent among bleeds, GUSTO mild/moderate access-site bleeding is not associated with increased risk. These data underscore the importance of strategies to minimize overall bleeding risk beyond vascular access site management.
acute coronary syndrome; bleeding; percutaneous coronary intervention
Patients with atrial fibrillation often have cardiovascular risk factors or known comorbid disease, yet the use of evidence-based primary and secondary prevention cardiac therapy among atrial fibrillation outpatients is unknown.
Using baseline data collected between June 2010 and August 2011 from 174 sites participating in ORBIT-AF, a US national registry of patients with atrial fibrillation coordinated from Durham, NC, USA, we examined professional guideline -recommended evidence-based therapy use for cardiovascular comorbid conditions and risk factors. Multivariable logistic regression was used to identify factors associated with receipt of all indicated evidence-based therapy.
Among 10096 enrolled patients, 93.5% were eligible for one or more evidence-based therapy. Among those eligible, 46.6% received all indicated therapies: 62.3% received an antiplatelet agent, 72.3% received a β-blocker, 59.5% received an angiotensin converting enzyme or angiotensin receptor blocker, 15.3% received an aldosterone antagonist, 65.7% received a statin, and 58.8% received implantable cardioverter-defibrillator. A minority of patients with coronary artery disease, diabetes mellitus, heart failure, and peripheral vascular disease received all indicated therapies (25.1%, 43.2%, 42.5%, and 43.4%, respectively). A total of 52.4% of patients had controlled hypertension and 74.6% of patients with hyperlipidemia received a statin. Factors associated with non-receipt of all indicated therapies included frailty, comorbid illness, geographic region, and antiarrhythmic drug therapy.
The majority of eligible atrial fibrillation outpatients did not receive all guideline-recommended therapies for cardiovascular comorbid conditions and risk factors. This represents a potential opportunity to improve atrial fibrillation patients’ quality of care and outcomes.
atrial fibrillation; evidence-based medicine; registry
All patients with atrial fibrillation (AF) require optimization of their ventricular rate. Factors leading to use of additional rhythm control in clinical practice have not been thoroughly defined.
The ORBIT-AF registry enrolled patients with AF from a broad range of practice settings and collected data on rate versus rhythm control, as indicated by the treating physician. Multivariable logistic regression analysis was performed to identify factors associated with each strategy.
Of 10,061 patients enrolled, 6,859 (68%) were managed with rate only control versus 3,202 (32%) with rhythm control. Patients managed with rate control were significantly older and more likely to have hypertension, heart failure, prior stroke, and gastrointestinal bleeds. They also had fewer AF-related symptoms (41% with no symptoms vs 31% for rhythm control). Systemic anticoagulation was prescribed for 5,448 (79%) rate-control patients versus 2,219 (69%) rhythm-control patients (P < .0001). After multivariable adjustment, patients with higher symptom scores (severe symptoms vs. none, OR 1.62, 95% CI 1.41–1.87) and those referred to electrophysiologists (OR 1.64, 95% CI 1.45–1.85) were more likely to be managed with a rhythm control strategy.
In this outpatient registry of US clinical practice, the majority of patients with AF were managed with rate control alone. Patients with more symptoms and who were treated by an electrophysiologist were more likely to receive rhythm-control therapies. A significant proportion of AF patients, regardless of treatment strategy, were not treated with anticoagulation for thromboembolism prophylaxis.
Time in therapeutic range (TTR) is a standard quality measure of the use of warfarin. We assessed the relative effects of rivaroxaban versus warfarin at the level of trial center TTR (cTTR) since such analysis preserves randomized comparisons.
Methods and Results
TTR was calculated using the Rosendaal method, without exclusion of international normalized ratio (INR) values performed during warfarin initiation. Measurements during warfarin interruptions >7 days were excluded. INRs were performed via standardized finger‐stick point‐of‐care devices at least every 4 weeks. The primary efficacy endpoint (stroke or non‐central nervous system embolism) was examined by quartiles of cTTR and by cTTR as a continuous function. Centers with the highest cTTRs by quartile had lower‐risk patients as reflected by lower CHADS2 scores (P<0.0001) and a lower prevalence of prior stroke or transient ischemic attack (P<0.0001). Sites with higher cTTR were predominantly from North America and Western Europe. The treatment effect of rivaroxaban versus warfarin on the primary endpoint was consistent across a wide range of cTTRs (P value for interaction=0.71). The hazard of major and non‐major clinically relevant bleeding increased with cTTR (P for interaction=0.001), however, the estimated reduction by rivaroxaban compared with warfarin in the hazard of intracranial hemorrhage was preserved across a wide range of threshold cTTR values.
The treatment effect of rivaroxaban compared with warfarin for the prevention of stroke and systemic embolism is consistent regardless of cTTR.
rivaroxaban; time in therapeutic range; warfarin
Peptic ulcer disease is a major cause of morbidity and mortality in the US with more than six million diagnoses annually. Ulcers are reported as the most common cause of hospitalization for upper gastrointestinal (GI) bleeding and are often a clinical concern due to the widespread use of aspirin and nonsteroidal anti-inflammatory drugs, both of which have been shown to induce ulcer formation. The finding that Helicobacter pylori infection (independent of aspirin use) is associated with the development of ulcers led to a more thorough understanding of the causes and pathogenesis of ulcers and an improvement in therapeutic options. However, many patients infected with H. pylori are asymptomatic and remain undiagnosed. Complicating matters is a current lack of understanding of the association between aspirin use and asymptomatic ulcer formation. Low-dose aspirin prescriptions have increased, particularly for cardioprotection. Unfortunately, the GI side effects associated with aspirin therapy continue to be a major complication in both symptomatic and asymptomatic patients. These safety concerns should be important considerations in the decision to use aspirin and warrant further education. The medical community needs to continue to improve awareness of aspirin-induced GI bleeding to better equip physicians and improve care for patients requiring aspirin therapy.
low-dose aspirin; cardioprotection; ulcers; Helicobacter pylori; gastrointestinal bleeding; cardiovascular disease
Dabigatran is a novel oral anticoagulant approved for thromboprophylaxis in atrial fibrillation. Adoption patterns of this new agent in community practice are unknown.
Methods and Results
We studied patterns of dabigatran use among patients enrolled in the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT‐AF) Registry between June 2010 and August 2011 and followed for 12 months. Among 9974 atrial fibrillation patients included, 1217 (12%) were treated with dabigatran during the study. Overall, patients receiving dabigatran were younger (median age 72 versus 75 years, P<0.0001), more likely to be white (92% versus 89%, P=0.005), more likely to have private insurance (33% versus 25%, P<0.0001), and less likely to have prior cardiovascular disease (4% versus 33%, P<0.0001). They had more new‐onset atrial fibrillation (8.8% versus 4.1%, P<0.0001), lower CHADS2 scores (estimated risk based on the presence of congestive heart failure, hypertension, aged ≥75 years, diabetes mellitus, and prior stroke or transient ischemic attack; mean 2.0 versus 2.3, P<0.0001), and lower Anticoagulation and Risk Factors in Atrial Fibrillation scores (mean 2.4 versus 2.8, P<0.0001). More than half (n=14/25, 56%) of patients with severe kidney disease were not prescribed reduced dosing, whereas 10% (n=91/920) with preserved renal function received lower dosing. Among patients not on dabigatran at baseline, 8% had dabigatran initiated during follow‐up. Patient education was significantly associated with switching from warfarin to dabigatran (adjusted odds ratio for postgraduate 1.73, P=0.007), whereas antiarrhythmic drug use significantly correlated with de novo adoption of dabigatran (adjusted odds ratio 2.4, P<0.0001).
Patients receiving dabigatran were younger and at a lower risk of stroke and bleeding. Patients appeared to drive switching from warfarin, whereas clinical characteristics influenced de novo start of dabigatran. These data suggest cautious early uptake of dabigatran, and more careful attention to dosing adjustments is warranted.
Clinical Trial Registration
URL: Clinicaltrials.gov. Unique identifier: NCT01165710.
anticoagulant; atrial fibrillation; dabigatran; dosing; pharmacoepidemiology
Older patients with atrial fibrillation (AF) and coronary artery disease (CAD) face high risk of stroke and bleeding with antithrombotic therapy. Balancing safe and effective use of aspirin, clopidogrel, and warfarin in this population is important.
From the Duke Databank for Cardiovascular Disease, we identified patients with AF ≥65 years old with angiographically confirmed CAD from 2000 to 2010. Antithrombotic use was described across age and Congestive heart failure, Hypertension, Age >75 years, Diabetes, prior Stroke/transient ischemic attack (CHADS2) stroke risk and Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) bleeding scores. Death and the composite of death, myocardial infarction, and stroke by antithrombotic strategy were reported.
Of 2,122 patients ≥65 years old with AF and CAD, 477 (22.5%) were ≥80 years old; 1,133 (53.4%) had acute coronary syndromes. Overall rates of aspirin, clopidogrel, and warfarin use were 83.4%, 34.6%, and 38.9%, respectively. Compared with patients 65 to 79 years old, more patients ≥80 years old were at high stroke risk (CHADS2 ≥2, 84.7% vs 57.8%) and high bleeding risk (ATRIA 5-10, 55.8% vs 23.3%). Warfarin use in both age groups increased with higher CHADS2 scores and decreased with higher ATRIA scores. Of patients ≥80 years old with CHADS2 ≥2, 150 (38.2%) received warfarin. Antithrombotic strategy was not associated with improved 1-year adjusted outcomes.
Among older patients with AF and CAD, overall warfarin use was low. Patients ≥80 years old at highest stroke risk received warfarin in similar proportions to the overall cohort. Further investigation into optimizing antithrombotic strategies in this population is warranted.
Larger infarct size measured by creatine kinase (CK)-MB release is associated with higher mortality and has been used as an important surrogate endpoint in the evaluation of new treatments for ST-segment elevation myocardial infarction (STEMI). Traditional approaches to quantify infarct size include the observed CK-MB peak and calculated CK-MB area under the curve (AUC). We evaluated alternative approaches to quantifying infarct size using CK-MB values, and the relationship between infarct size and clinical outcomes.
Of 1,850 STEMI patients treated with reperfusion therapy in the COMplement inhibition in Myocardial infarction treated with Angioplasty (COMMA) (percutaneous coronary intervention (PCI)-treated) and the COMPlement inhibition in myocardial infarction treated with thromboLYtics (COMPLY) (fibrinolytic-treated) trials, 1,718 (92.9%) (COMMA, n = 868; COMPLY, n = 850) had at least five of nine protocol-required CK-MB measures. In addition to traditional methods, curve-fitting techniques were used to determine CK-MB AUC and estimated peak CK-MB. Cox proportional hazards modeling assessed the univariable associations between infarct size and mortality, and the composite of death, heart failure, shock and stroke at 90 days.
In COMPLY, CK-MB measures by all methods were significantly associated with higher mortality (hazard ratio range per 1,000 units increase: 1.09 to 1.13; hazard ratio range per 1 standard deviation increase: 1.41 to 1.62; P <0.01 for all analyses). In COMMA, the associations were similar but did not reach statistical significance. For the composite outcome of 90-day death, heart failure, shock and stroke, the associations with all CK-MB measures were statistically significant in both the COMMA and COMPLY trials.
Sophisticated curve modeling is an alternative to infarct-size quantification in STEMI patients, but it provides information similar to that of more traditional methods. Future studies will determine whether the same conclusion applies in circumstances other than STEMI, or to studies with different frequencies and patterns of CK-MB data collection.
Creatine kinase-MB; Infarct size; ST-segment elevation myocardial infarction; Clinical outcomes
Vitamin K antagonist (VKA) therapy remains the most common method of stroke prevention in patients with atrial fibrillation. Time in therapeutic range (TTR) is a widely cited measure of the quality of VKA therapy. We sought to identify factors associated with TTR in a large, international clinical trial.
Methods and Results
TTR (international normalized ratio [INR] 2.0 to 3.0) was determined using standard linear interpolation in patients randomized to warfarin in the ROCKET AF trial. Factors associated with TTR at the individual patient level (i‐TTR) were determined via multivariable linear regression. Among 6983 patients taking warfarin, recruited from 45 countries grouped into 7 regions, the mean i‐TTR was 55.2% (SD 21.3%) and the median i‐TTR was 57.9% (interquartile range 43.0% to 70.6%). The mean time with INR <2 was 29.1% and the mean time with an INR >3 was 15.7%. While multiple clinical features were associated with i‐TTR, dominant determinants were previous warfarin use (mean i‐TTR of 61.1% for warfarin‐experienced versus 47.4% in VKA‐naïve patients) and geographic region where patients were managed (mean i‐TTR varied from 64.1% to 35.9%). These effects persisted in multivariable analysis. Regions with the lowest i‐TTRs had INR distributions shifted toward lower INR values and had longer inter‐INR test intervals.
Independent of patient clinical features, the regional location of medical care is a dominant determinant of variation in i‐TTR in global studies of warfarin. Regional differences in mean i‐TTR are heavily influenced by subtherapeutic INR values and are associated with reduced frequency of INR testing.
Clinical Trial Registration
URL: ClinicalTrials.gov. Unique identifier: NCT00403767.
anticoagulants; arrhythmia; embolism; prevention; risk factors
The Superior Yield of the New Strategy of Enoxaparin, Revascularization, and GlYcoprotein IIb/IIIa inhibitors (SYNERGY) was a randomized, open-label, multicenter clinical trial comparing 2 anticoagulant drugs on the basis of time-to-event endpoints. In contrast to other studies of these agents, the primary, intent-to-treat analysis did not find evidence of a difference, leading to speculation that premature discontinuation of the study agents by some subjects may have attenuated the apparent treatment effect and thus to interest in inference on the difference in survival distributions were all subjects in the population to follow the assigned regimens, with no discontinuation. Such inference is often attempted via ad hoc analyses that are not based on a formal definition of this treatment effect. We use SYNERGY as a context in which to describe how this effect may be conceptualized and to present a statistical framework in which it may be precisely identified, which leads naturally to inferential methods based on inverse probability weighting.
Dynamic treatment regime; Inverse probability weighting; Potential outcomes; Proportional hazards model
Despite advances in pharmacologic therapy and invasive management strategies for patients with non-ST-segment elevation acute coronary syndromes (NSTE ACS), these patients still suffer substantial morbidity and mortality.
The objective of this study was to analyze independent predictors of 1-year mortality in patients with high-risk NSTE ACS.
DESIGN AND PARTICIPANTS
A total of 9,978 patients were assigned to receive enoxaparin or unfractionated heparin (UFH) in this prospective, randomized, open-label, international trial.
Vital status at 1 year was collected. Univariable and multivariable predictors of 1-year mortality were identified. Three different multivariable regression models were constructed to identify: (1) predictors of 30-day mortality; (2) predictors of 1-year mortality; (3) predictors of 1-year mortality in 30-day survivors. The last model is the focus of this paper.
Overall, 9,922 (99.4%) of patients had 1-year follow-up. Of the 56 patients (37 UFH-assigned and 19 enoxaparin-assigned) without 1-year data, 11 patients were excluded because of withdrawal of consent, and 45 could not be located. One-year mortality was 7.5% (7.7% enoxaparin-assigned patients; 7.3% UFH-assigned patients; P = 0.4). In patients surviving 30 days after enrollment, independent predictors of 1-year mortality included factors known at baseline such as increased age, male sex, decreased weight, having ever smoked, decreased creatinine clearance, ST-segment depression, history of diabetes, history of angina, congestive heart failure, coronary artery bypass grafting, increased heart rate, rales, increased hematocrit, lowered hemoglobin, and higher platelet count. Factors predictive of mortality during the hospitalization and 30-day follow-up period were decreased weight at 30 days from baseline, atrial fibrillation, decreased nadir platelet, no use of beta-blockers and statins up to 30 days, and not receiving an intervention (c-index = 0.82).
Easily determined baseline clinical characteristics can be used to predict 1-year mortality with reasonable discriminative power. These models corroborate prior work in a contemporary aggressively managed population. A model to predict 1-year mortality in patients surviving at least 30 days may be quite helpful to healthcare providers in setting expectations and goals with patients after ACS.
non-ST-segment elevation acute coronary syndrome; predictors; mortality; outcomes; low-molecular-weight heparin; unfractionated heparin
While natriuretic peptides have demonstrated diagnostic and prognostic potential in cardiac disorders, little is known about their relationship with the onset and quantification of myocardial infarction. The relationship of serial N-terminal pro-brain natriuretic peptide (NT-proBNP) with duration from symptom onset, infarct size and prognosis in ST elevation myocardial infarction (STEMI) patients treated with primary percutaneous intervention was examined.
METHODS AND RESULTS
Three hundred thirty-one STEMI patients in the COMplement inhibition in Myocardial infarction treated with Angioplasty (COMMA) trial, which evaluated pexelizumab versus placebo, were studied. NT-proBNP (pg/mL) was measured at randomization, 24 h and 72 h; creatine kinase-MB area under the curve was measured at 72 h; and QRS score was assessed at discharge. Prognosis was ascertained from the 90-day composite clinical outcome of death, shock, stroke and congestive heart failure. Multivariate logistical regression was used to adjust for baseline characteristics for models at randomization, 24 h and 72 h. NT-proBNP was higher in patients with longer time from symptom onset (P<0.001) and correlated with measures of infarct size, including the area under the curve (P<0.001) and QRS score (P<0.001). Patients reaching the primary end point had markedly higher NT-proBNP at each sampling period (P<0.001). NT-proBNP at all time points was the strongest independent predictor of the primary end point in the multivariate model: in the 24 h model, only age and 24 h NT-proBNP (C-index 0.83); and only age, Killip class and NT-proBNP was in the 72 h model (C-index 0.85).
Higher NT-proBNP at 24 h correlated with larger infarct size and worse clinical outcomes. NT-proBNP at baseline, 24 h and 72 h after presentation with acute STEMI, is an independent predictor of a poor outcome and adds clinically useful prognostic information.
Clinical trial; Myocardial infarction; Natriuretic peptides
Cardiac biomarkers are routinely obtained in the setting of suspected myocardial ischemia and infarction. Evidence suggests these markers may correlate with functional and clinical outcomes, but the strength of this correlation is unclear. The relationship between enzyme measures of myocardial necrosis and left ventricular performance and adverse clinical outcomes were explored.
Creatine kinase (CK) and CK-MB data were analyzed, as were left ventricular ejection fraction (LVEF) by angiogram, and infarct size by single-photon emission computed tomography (SPECT) imaging in patients in 2 trials: Prompt Reperfusion In Myocardial-infarction Evolution (PRIME), and Efegatran and Streptokinase to Canalize Arteries Like Accelerated Tissue plasminogen activator (ESCALAT). Both trials evaluated efegatran combined with thrombolysis for treating acute ST-segment elevation myocardial infarction (STEMI).
Peak CK and CK area-under-the-curve (AUC) correlated significantly with SPECT-determined infarct size 5 to 10 days after enrollment. Peak CK had a statistically significant correlation with LVEF, but CK-AUC and LVEF correlation were less robust. Statistically significant correlations exist between SPECT-determined infarct size and peak CK-MB and CK-MB AUC. However, there was no correlation with LVEF for peak CK-MB and CK-MB AUC. The combined outcome of congestive heart failure and death were significantly associated with CK AUC, CK-MB AUC, peak CK, and peak CK-MB measurements.
Peak CK and CK-MB values and AUC calculations have significant correlation with functional outcomes (LVEF- and SPECT-determined infarct size) and death or CHF outcomes in the setting of STEMI. Cardiac biomarkers provide prognostic information and may serve as valid endpoint measurements for phase II clinical trials.
Limited information has been published regarding how specific processes for event adjudication can affect event rates in trials. We reviewed nonfatal myocardial infarctions (MIs) reported by site investigators in the international Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin (Eptifibatide) Therapy (PURSUIT) trial and those adjudicated by a central clinical events committee (CEC) to determine the reasons for differences in event rates.
The PURSUIT trial randomised 10,948 patients with acute coronary syndromes to receive eptifibatide or placebo. The primary end-point was death or post-enrolment MI at 30 days as assessed by the CEC; this end-point was also constructed using site-reported events. The CEC identified suspected MIs by systematic review of clinical, cardiac enzyme, and electrocardiographic data.
The CEC identified 5005 (46%) suspected events, of which 1415 (28%) were adjudicated as MI. The site investigator and CEC assessments of whether a MI had occurred disagreed in 983 (20%) of the 5005 patients with suspected MI, mostly reflecting site misclassification of post-enrolment MIs (as enrolment MIs) or underreported periprocedural MIs. Patients for whom the CEC and site investigator agreed that no end-point MI had occurred had the lowest mortality at 30 days and between 30 days and 6 months, and those with agreement that a MI had occurred had the highest mortality.
CEC adjudication provides a standard, systematic, independent, and unbiased assessment of end-points, particularly for trials that span geographic regions and clinical practice settings. Understanding the review process and reasons for disagreement between CEC and site investigator assessments of MI is important to design future trials and interpret event rates between trials.
acute coronary syndromes; adjudication; clinical events committee; end-points; myocardial infarction
Clinical events committees (CEC) are used routinely to adjudicate suspected end-points in cardiovascular trials, but little information has been published about the various processes used. We reviewed results of the CEC process used to identify and adjudicate suspected end-point (post-enrolment) myocardial infarction (MI) in the large Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin (Eptifibatide) Therapy (PURSUIT) trial.
The PURSUIT trial randomised 10,948 patients with acute coronary syndromes to receive eptifibatide or placebo. A central adjudication process was established prospectively to identify all suspected MIs and adjudicate events based on protocol definitions of MI. Suspected MIs were identified by systematic review of data collection forms, cardiac enzyme results, and electrocardiograms. Two physicians independently reviewed all suspected events. If they disagreed whether a MI had occurred, a committee of cardiologists adjudicated the case.
The CEC identified 5005 patients with suspected infarction (46%), of which 1415 (28%) were adjudicated as end-point infarctions. As expected, the process identified more end-point events than did the site investigators. Absolute and relative treatment effects of eptifibatide were smaller when using CEC-determined MI rates rather than site investigator-determined rates. The site-investigator reporting of MI and the CEC assessment of MI disagreed in 20% of the cases reviewed by the CEC.
End-point adjudication by a CEC is important, to provide standardised, systematic, independent, and unbiased assessment of end-points, particularly in trials that span geographic regions and clinical practice settings. Understanding the CEC process used is important in the interpretation of trial results and event rates.
acute coronary syndromes; adjudication; clinical events committee; clinical trials; myocardial infarction
Temporary interruption of oral anticoagulation for procedures is often required, and some propose using bridging anticoagulation. However, the use and outcomes of bridging during oral anticoagulation interruptions in clinical practice are unknown.
Methods and Results—
The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry is a prospective, observational registry study of US outpatients with atrial fibrillation. We recorded incident temporary interruptions of oral anticoagulation for a procedure, including the use and type of bridging therapy. Outcomes included multivariable-adjusted rates of myocardial infarction, stroke or systemic embolism, major bleeding, cause-specific hospitalization, and death within 30 days. Of 7372 patients treated with oral anticoagulation, 2803 overall interruption events occurred in 2200 patients (30%) at a median follow-up of 2 years. Bridging anticoagulants were used in 24% (n=665), predominantly low-molecular-weight heparin (73%, n=487) and unfractionated heparin (15%, n=97). Bridged patients were more likely to have had prior cerebrovascular events (22% versus 15%; P=0.0003) and mechanical valve replacements (9.6% versus 2.4%; P<0.0001); however, there was no difference in CHA2DS2-VASc scores (scores ≥2 in 94% versus 95%; P=0.5). Bleeding events were more common in bridged than nonbridged patients (5.0% versus 1.3%; adjusted odds ratio, 3.84; P<0.0001). The incidence of myocardial infarction, stroke or systemic embolism, major bleeding, hospitalization, or death within 30 days was also significantly higher in patients receiving bridging (13% versus 6.3%; adjusted odds ratio, 1.94; P=0.0001).
Bridging anticoagulation is used in one quarter of anticoagulation interruptions and is associated with higher risk for bleeding and adverse events. These data do not support the use of routine bridging, and additional data are needed to identify best practices concerning anticoagulation interruptions.
Clinical Trial Registration—
URL: http://www.clinicaltrials.gov. Unique identifier: NCT01165710.
anticoagulants; atrial fibrillation; outcome assessment (health care)