Mediators of the effect of ertugliflozin on a composite kidney outcome in patients with type 2 diabetes and atherosclerotic cardiovascular disease: analyses from VERTIS CV

Introduction

Sodium–glucose cotransporter 2 (SGLT2) inhibitors have been shown to slow the decline of kidney function in outcome trials, but the biological mediator(s) underlying the therapeutic benefit are not well established.

Purpose

We performed a post-hoc analysis exploring potential mediators of the effects of the SGLT2 inhibitor ertugliflozin on the VERTIS CV exploratory kidney composite outcome (sustained 40% decrease from baseline in estimated glomerular filtration rate [eGFR], chronic kidney replacement therapy or kidney death).

Methods

In VERTIS CV, 8246 participants with type 2 diabetes mellitus and established atherosclerotic cardiovascular disease were randomised to placebo, ertugliflozin 5 mg or 15 mg (pooled for analyses, as prospectively planned), and were followed for a mean of 3.5 years. The hazard ratio (HR; 95% confidence interval) for the pre-specified exploratory kidney composite outcome was 0.66 (0.50, 0.88). Cox regression models were used to evaluate covariates that were significantly differentially changed from baseline with ertugliflozin treatment as candidate mediators, with a mediator identified as a covariate when added to an unadjusted model of randomised treatment assignment a) yielded a larger hazard ratio; and b) the mediator retained P<0.05 in the model (eGFR was excluded as a covariate). The percentage of mediation was determined by the proportional increase in the HR between the unadjusted and adjusted models for each post-randomisation period: early (first change from baseline measurement) and average (weighted average of change from baseline from all post-baseline measurements). Each potential mediator was tested individually, so across analyses, mediation % sums to >100%.

Results

Of 22 covariates significantly changed by ertugliflozin, nine were identified as potential mediators (Table). The covariates with a high percentage of mediation were those related to changes in blood erythrocytes (haemoglobin, haematocrit and red blood cell mass), with average changes in haemoglobin having the highest percentage of mediation (61.8%). Serum uric acid was associated with a mediation of 29.4% and 50.0% for the early and average post-randomisation effect periods, respectively. Early changes in glycated haemoglobin had a large mediation (50%), but the average change during the trial was not significant. Average change in serum albumin had a large mediation (29.4%). Average changes in body weight and systolic blood pressure had percentages of mediation of 41.2% and 14.7%, respectively.

Conclusion

Multiple factors may be involved in the reduction of the kidney composite outcome observed with ertugliflozin. In the short-term, changes in glycaemia had a high mediation effect. Over the long-term, changes suggestive of haemoconcentration and/or haematopoiesis (natriuresis-related effects), showed the highest percentage of mediation, followed by changes in serum uric acid and body weight (glucosuria-related effects).

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Sponsored by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA in collaboration with Pfizer Inc., New York, NY, USA

Mediation analyses of the effect of ertugliflozin on hospitalisation for heart failure in patients with type 2 diabetes and atherosclerotic cardiovascular disease from the VERTIS CV trial

Introduction

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce risk of hospitalisation for heart failure (HHF) in outcome trials, but the biological mediators underlying the therapeutic benefit are not well established.

Purpose

To identify potential biological mediators through which ertugliflozin reduces risk of HHF.

Methods

In VERTIS CV, 8246 patients with type 2 diabetes and atherosclerotic cardiovascular disease were randomised to ertugliflozin 5 or 15 mg (observations pooled as prospectively planned) or placebo. Cox regression models were used to evaluate the associations between changes in 26 potential mediators with outcomes. Potential mediators were selected based on proposed mechanisms and/or differential change from baseline with SGLT2 inhibitors. Mediation criteria required 1) significant (P<0.05 for change from baseline) effects of ertugliflozin vs placebo on each potential mediator; and 2) significant (P<0.05) association of change in post-randomisation levels of the potential mediator with risk of HHF when added to an unadjusted model of randomised treatment assignment. Percent mediation was determined by comparing the unadjusted hazard ratio and hazard ratio adjusted for change in the potential mediator of interest. Each covariate was tested individually, such that percent mediation across the analyses summed to >100%. Time-dependent models were used to evaluate associations between early (change from baseline for the first post-baseline measurement) and average (weighted average of change from baseline using all post-baseline measurements) changes in covariates with clinical outcomes.

Results

Over a mean of 3.5 years, the incidence rate of HHF was 0.7 and 1.1 per 100 patient-years with ertugliflozin and placebo, respectively. Among 26 candidate mediators, 9 and 13 met the mediation criteria based on early and average changes, respectively. The 3 covariates with the largest mediating effects of early changes included haematocrit (40%), haemoglobin (27%) and HDL-C (23%) (Table); other significant biomarkers included urine albumin/creatinine ratio, and serum albumin, uric acid, chloride, protein and sodium. The 3 biomarkers with the largest mediating effects in average changes included haemoglobin (63%), albumin (50%) and uric acid (47%) (Table); other significant biomarkers included haematocrit, urine albumin/creatinine ratio, body weight, serum protein and chloride, systolic blood pressure, ALT, BUN, eGFR and heart rate.

Conclusions

In these analyses from the VERTIS CV trial, potential markers of volume status and haemoconcentration and/or haematopoiesis were the strongest mediators of the effect of ertugliflozin on reducing risk of HHF in the early and average change periods. Other potential mediators included uric acid, lipid markers and kidney parameters. These findings provide insights into potential mechanisms through which ertugliflozin, and potentially the SGLT2 inhibitor class, may prevent HHF.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Sponsored by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and Pfizer Inc., New York, NY, USA.

Effects of canagliflozin on hyperkalaemia and serum potassium in people with diabetes and chronic kidney disease: insights from the CREDENCE trial

Background

Hyperkalaemia is a common complication of type 2 diabetes mellitus (T2DM) and limits the optimal use of agents that block the renin-angiotensin aldosterone system (RAAS), particularly in patients with chronic kidney disease (CKD). In patients with CKD, sodium glucose cotransporter 2 (SGLT2) inhibitors provide cardiorenal protection, but whether they affect the risk of hyperkalaemia remains uncertain.

Purpose

We sought to assess the effect of canagliflozin on hyperkalaemia and other potassium-related outcomes in people with T2DM and CKD by conducting a post-hoc analysis of the CREDENCE trial.

Methods

The CREDENCE trial randomized 4401 participants with T2DM and CKD to the SGLT2 inhibitor canagliflozin or matching placebo. In this post-hoc analysis using an intention-to-treat approach, we assessed the effect of canagliflozin on a composite outcome of time to either investigator-reported hyperkalaemia or the initiation of potassium binders. We also analysed effects on central laboratory-determined hyper- and hypokalaemia (serum potassium ≥6.0 and <3.5 mmol/L, respectively) and change in serum potassium.

Results

At baseline the mean serum potassium in canagliflozin and placebo arms was 4.5 mmol/L; 4395 (99.9%) participants were receiving renin angiotensin system blockade. Canagliflozin reduced the risk of investigator-reported hyperkalaemia or initiation of potassium binders (HR 0.78, 95% CI 0.64–0.95, p=0.014; Figure 1). The incidence of laboratory-determined hyperkalaemia was similarly reduced (HR 0.77, 95% CI 0.61–0.98, p=0.031; Figure 2); the risk of hypokalaemia (HR 0.92, 95% CI 0.71–1.20, p=0.53) was not increased. Mean serum potassium over time with canagliflozin was similar to that of placebo.

Conclusion

Among patients treated with RAAS inhibitors, SGLT2 inhibition with canagliflozin may reduce the risk of hyperkalaemia in people with T2DM and CKD without increasing the risk of hypokalaemia.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Cardiorenal outcomes with ertugliflozin by baseline metformin use: post-hoc analyses of the VERTIS CV trial

Introduction

We analysed data from the VERTIS CV trial that investigated the CV and kidney safety and efficacy of the sodium-glucose cotransporter 2 (SGLT2) inhibitor ertugliflozin (ERTU) vs placebo (PBO) to assess the impact of metformin (MET) use at baseline (BL). These analyses are timely because the recent ESC guidelines recommendation to use SGLT2 inhibitor or GLP-1 RAs as initial glucose-lowering therapy in patients with type 2 diabetes (T2D) with or at high risk for atherosclerotic cardiovascular disease (ASCVD) has been questioned because outcome trials of these drug classes included a large proportion of patients with MET as background therapy, yet MET was not used at BL in approximately 25% of patients in each trial.

Purpose

These analyses determined cardiorenal endpoints of VERTIS CV according to use of BL MET to assess for evidence of treatment effect modification for ERTU by BL MET use, adjusting for the probability (propensity) of BL MET use.

Methods

VERTIS CV was an international, double-blind, PBO-controlled trial of 2 doses of ERTU (5 mg; 15 mg) vs PBO in patients with T2DM and ASCVD. As prospectively planned, the 2 ERTU dose groups were combined for all analyses vs PBO. Differences in risk of CV and kidney outcomes between ERTU and PBO across subgroups by BL MET use were conducted using Cox proportional hazards model along with propensity adjustment using inverse probability for treatment weighting to account for differences in patient mix between those with and without BL MET influenced by individual BL characteristics and risk factors. Treatment (categorical), BL MET use (categorical) and the interaction term between treatment and BL MET use subgroup (no or yes) were used in each model to assess effect modification by BL MET use. Hazard ratio and 95% CI are presented along with Pinteraction for evaluation of treatment effect modification by BL MET use.

Results

In VERTIS CV, 8246 patients were randomised to ERTU 5 mg, 15 mg or PBO. Of these, 6286 (76%) patients used MET (alone or with other glucose-lowering agents [GLA]) at BL. Differences in BL characteristics by BL MET use subgroup (no or yes) included a higher mean UACR (204.4 vs 129.8 mg/g), more patients with eGFR <60 mL/min/1.73 m2 (34.8% vs 17.9%), more patients on a single GLA (76.9% vs 18.3%), higher insulin use (67.6% vs 40.9%), lower sulphonylurea use (32.2% vs 43.8%) and a slightly longer disease duration (14.4 vs 12.5 years) in the subgroup without vs with BL MET, respectively. No significant differences in the relative risk for cardiorenal outcomes were observed with or without BL MET use (Figure; all Pinteraction values >0.05).

Conclusions

In VERTIS CV, there was no evidence for effect modification by BL MET use on the effects of ERTU on cardiorenal outcomes in patients with T2D and ASCVD.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Sponsored by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and Pfizer Inc., New York, NY, USA.

P34 The effect of sex on the efficacy and safety of dabigatran dual therapy in atrial fibrillation after PCI: a subgroup analysis from the RE-DUAL PCI trial

Funding Acknowledgements

Boehringer Ingelheim International GmbH

On Behalf

The Re-DUAL PCI Investigators

Background

The RE-DUAL PCI study (NCT02164864) compared dabigatran dual antithrombotic therapy (D-DAT) with warfarin triple antithrombotic therapy (W-TAT) in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI). As previously reported D-DAT reduced bleeding compared with W-TAT and was non-inferior with regard to thromboembolic events. 

Aim 

The aim of this subgroup analysis of RE-DUAL was to assess the relationship between sex and treatment effects of D-DAT and W-TAT on bleeding and thromboembolic outcomes.

Methods

Patients were randomized to receive W-TAT (warfarin, clopidogrel or ticagrelor, and aspirin) or D-DAT (dabigatran 110 or 150 mg twice daily with clopidogrel or ticagrelor; D110- or D150-DAT). Younger patients (aged < 80 yrs. [< 70 yrs. in Japan]) and US patients irrespective of age received D110-DAT, D150-DAT or W-TAT; older patients (aged ≥ 80 yrs. in non-US countries [≥ 70 yrs. in Japan]) received only D110-DAT or W-TAT. Bleeding and thromboembolic outcomes were assessed according to treatment group and by sex (female vs. male).

Results

A total of 2725 patients were randomized; 2070 patients were male (76.0%) and 655 (24.0%) were female. Overall females were older at time of PCI than males (73.2 ± 7.9 vs. 70.0 ± 8.8 years). The mean CHA2DS2-VASc and modified HAS-BLED scores were higher in women at 4.5 and 2.8, respectively, than in men at 3.3 and 2.7, respectively. 

For the primary endpoint of major bleeding events or clinically relevant non-major bleeding events, treatment effects of D110-DAT vs. W-TAT were consistent for female and male patients (females: HR 0.69, 95% CI 0.47-1.01, males HR 0.46, 95%CI 0.37-0.59, interaction p-value 0.084). Similarly, consistent treatment effects were seen for the primary endpoint with D150-DAT vs W-TAT in female and male patients (females HR 0.74, 95% CI 0.48-1.16, males HR 0.71, 95% CI 0.56-0.90, interaction p value 0.83). 

No interaction between sex and treatment was observed for D110- or D150-DAT vs W-TAT with regard to the composite efficacy endpoint of death, thromboembolic events or unplanned revascularization (interaction p values 0.73 and 0.72, respectively) (figure).

Conclusion

The treatment effect of dabigatran 110 mg and 150 mg dual therapy vs warfarin triple therapy was consistent across sex groups. This suggests that female and male patients with AF undergoing PCI should be treated equally in terms of the dosage of dabigatran selected for dual therapy strategies.

Abstract P34 Figure. Re-DUAL sex subgroup analysis

Randomized Evaluation of the Effects of Anacetrapib through Lipid-modification (REVEAL)-A large-scale, randomized, placebo-controlled trial of the clinical effects of anacetrapib among people with established vascular disease: Trial design, recruitment, and baseline characteristics

Patients with prior vascular disease remain at high risk for cardiovascular events despite intensive statin-based treatment. Inhibition of cholesteryl ester transfer protein by anacetrapib reduces low-density lipoprotein (LDL) cholesterol by around 25% to 40% and more than doubles high-density lipoprotein (HDL) cholesterol. However, it is not known if these apparently favorable lipid changes translate into reductions in cardiovascular events.

METHODS

The REVEAL study is a randomized, double-blind, placebo-controlled clinical trial that is assessing the efficacy and safety of adding anacetrapib to effective LDL-lowering treatment with atorvastatin for an average of at least 4years among patients with preexisting atherosclerotic vascular disease. The primary assessment is an intention-to-treat comparison among all randomized participants of the effects of allocation to anacetrapib on major coronary events (defined as the occurrence of coronary death, myocardial infarction, or coronary revascularization).

RESULTS

Between August 2011 and October 2013, 30,449 individuals in Europe, North America, and China were randomized to receive anacetrapib 100mg daily or matching placebo. Mean (SD) age was 67 (8) years, 84% were male, 88% had a history of coronary heart disease, 22% had cerebrovascular disease, and 37% had diabetes mellitus. At the randomization visit (after at least 8weeks on a protocol-defined atorvastatin regimen), mean plasma LDL cholesterol was 61 (15) mg/dL and HDL cholesterol was 40 (10) mg/dL.

INTERPRETATION

The REVEAL trial will provide a robust evaluation of the clinical efficacy and safety of adding anacetrapib to an effective statin regimen. Results are anticipated in 2017.

Collaborative meta-analysis of individual participant data from observational studies of Lp-PLA2 and cardiovascular diseases

BACKGROUND

A large number of observational epidemiological studies have reported generally positive associations between circulating mass and activity levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA2 markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors.

OBJECTIVES

By combination of data from individual participants from all relevant observational studies in a systematic 'meta-analysis', with correction for regression dilution (using available data on serial measurements of Lp-PLA2), the Lp-PLA2 Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA2 with coronary heart disease (and, where data are sufficient, with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA2 and cardiovascular outcomes.

METHODS

A central database is being established containing data on circulating Lp-PLA2 values, sex and other potential confounding factors, age at baseline Lp-PLA2 measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA2 will yield information on a total of about 15 000 cardiovascular disease endpoints.

Effects of empagliflozin on blood pressure and markers of arterial stiffness and vascular resistance in patients with type 2 diabetes

AIMS

To determine the effects of empagliflozin on blood pressure (BP) and markers of arterial stiffness and vascular resistance in patients with type 2 diabetes mellitus (T2DM).

METHODS

We conducted a post hoc analysis of data from a phase III trial in patients with T2DM and hypertension receiving 12 weeks' empagliflozin and four phase III trials in patients with T2DM receiving 24 weeks' empagliflozin (cohort 1, n = 823; cohort 2, n = 2477). BP was measured using 24-h BP monitoring (cohort 1) or seated office measurements (cohort 2).

RESULTS

Empagliflozin reduced systolic BP (SBP) and diastolic BP in both cohorts (p < 0.001 vs placebo), without increasing heart rate. Empagliflozin reduced pulse pressure (PP; adjusted mean difference vs placebo cohort 1: -2.3 mmHg; cohort 2: -2.3 mmHg), mean arterial pressure (MAP; cohort 1, -2.3 mmHg; cohort 2, -2.1 mmHg) and double product (cohort 1, -385 mmHg × bpm; cohort 2, -369 mmHg × bpm) all p < 0.001 vs placebo. There was a trend towards a reduction in the ambulatory arterial stiffness index (AASI) with empagliflozin in cohort 1 (p = 0.059 vs placebo). AASI was not measured in cohort 2. Subgroup analyses showed that there were greater reductions in PP with increasing baseline SBP in cohort 1 (p = 0.092). In cohort 2, greater reductions in MAP were achieved in patients with higher baseline SBP (p = 0.027) and greater reductions in PP were observed in older patients (p = 0.011).

CONCLUSIONS

Empagliflozin reduced BP and had favourable effects on markers of arterial stiffness and vascular resistance.

Genetic risk, coronary heart disease events, and the clinical benefit of statin therapy: an analysis of primary and secondary prevention trials

BACKGROUND

Genetic variants have been associated with the risk of coronary heart disease. In this study, we tested whether or not a composite of these variants could ascertain the risk of both incident and recurrent coronary heart disease events and identify those individuals who derive greater clinical benefit from statin therapy.

METHODS

A community-based cohort study (the Malmo Diet and Cancer Study) and four randomised controlled trials of both primary prevention (JUPITER and ASCOT) and secondary prevention (CARE and PROVE IT-TIMI 22) with statin therapy, comprising a total of 48,421 individuals and 3477 events, were included in these analyses. We studied the association of a genetic risk score based on 27 genetic variants with incident or recurrent coronary heart disease, adjusting for traditional clinical risk factors. We then investigated the relative and absolute risk reductions in coronary heart disease events with statin therapy stratified by genetic risk. We combined data from the different studies using a meta-analysis.

FINDINGS

When individuals were divided into low (quintile 1), intermediate (quintiles 2-4), and high (quintile 5) genetic risk categories, a significant gradient in risk for incident or recurrent coronary heart disease was shown. Compared with the low genetic risk category, the multivariable-adjusted hazard ratio for coronary heart disease for the intermediate genetic risk category was 1·34 (95% CI 1·22-1·47, p<0·0001) and that for the high genetic risk category was 1·72 (1·55-1·92, p<0·0001). In terms of the benefit of statin therapy in the four randomised trials, we noted a significant gradient (p=0·0277) of increasing relative risk reductions across the low (13%), intermediate (29%), and high (48%) genetic risk categories. Similarly, we noted greater absolute risk reductions in those individuals in higher genetic risk categories (p=0·0101), resulting in a roughly threefold decrease in the number needed to treat to prevent one coronary heart disease event in the primary prevention trials. Specifically, in the primary prevention trials, the number needed to treat to prevent one such event in 10 years was 66 in people at low genetic risk, 42 in those at intermediate genetic risk, and 25 in those at high genetic risk in JUPITER, and 57, 47, and 20, respectively, in ASCOT.

INTERPRETATION

A genetic risk score identified individuals at increased risk for both incident and recurrent coronary heart disease events. People with the highest burden of genetic risk derived the largest relative and absolute clinical benefit from statin therapy.

FUNDING

National Institutes of Health.

Health economic analysis of ticagrelor in patients with acute coronary syndromes intended for non-invasive therapy

Objective

To investigate the cost effectiveness of ticagrelor versus clopidogrel in patients with acute coronary syndromes (ACS) in the Platelet Inhibition and Patient Outcomes (PLATO) study who were scheduled for non-invasive management.

Methods

A previously developed cost effectiveness model was used to estimate long-term costs and outcomes for patients scheduled for non-invasive management. Healthcare costs, event rates and health-related quality of life under treatment with either ticagrelor or clopidogrel over 12 months were estimated from the PLATO study. Long-term costs and health outcomes were estimated based on data from PLATO and published literature sources. To investigate the importance of different healthcare cost structures and life expectancy for the results, the analysis was carried out from the perspectives of the Swedish, UK, German and Brazilian public healthcare systems.

Results

Ticagrelor was associated with lifetime quality-adjusted life-year (QALY) gains of 0.17 in Sweden, 0.16 in the UK, 0.17 in Germany and 0.13 in Brazil compared with generic clopidogrel, with increased healthcare costs of €467, €551, €739 and €574, respectively. The cost per QALY gained with ticagrelor was €2747, €3395, €4419 and €4471 from a Swedish, UK, German and Brazilian public healthcare system perspective, respectively. Probabilistic sensitivity analyses indicated that the cost per QALY gained with ticagrelor was below conventional threshold values of cost effectiveness with a high probability.

Conclusions

Treatment of patients with ACS scheduled for 12 months’ non-invasive management with ticagrelor is associated with a cost per QALY gained below conventional threshold values of cost effectiveness compared with generic clopidogrel.

Trial registration number

NCT000391872.

Risk factors for NSAID-associated upper GI clinical events in a long-term prospective study of 34 701 arthritis patients

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAID)-related GI effects vary based on patient characteristics.

AIMS

To assess risk factors for NSAID-associated upper GI clinical events and dyspepsia.

METHODS

Patients ≥50 years with osteoarthritis or rheumatoid arthritis were randomized to etoricoxib or diclofenac in a prespecified intent-to-treat analysis of three double-blind randomized trials. Potential risk factors for upper GI clinical events (bleeding, perforation, obstruction, or ulcer), complicated events (perforation, obstruction, bleeding) and discontinuations due to dyspepsia were assessed with Cox proportional hazard models.

RESULTS

Significant predictors of clinical events and complicated events included age ≥65 years [hazards ratios (HRs) = 2.25 (1.84-2.76), 4.09 (2.82-5.92)], prior event [HRs = 2.57 (1.94-3.39), 3.23 (2.09-5.00)], low-dose aspirin [HRs = 2.34 (1.87-2.92), 3.41 (2.33-5.00)] and corticosteroid [HRs = 1.85 (1.41-2.43), 2.09 (1.29-3.38)]. Predictors of discontinuation due to dyspepsia included prior dyspepsia [HR = 1.78 (1.44-2.00)], prior event [HR = 1.78 (1.40-2.27)] and age ≥65 years [HR = 1.35 (1.16-1.57)].

CONCLUSIONS

Assessment for age ≥65 years, prior upper GI clinical events and low-dose aspirin use are key in identifying patients who should either avoid NSAIDs or employ management strategies to reduce NSAID-associated upper GI events. Prior dyspepsia or upper GI clinical events and age ≥65 years also predict an increased risk of developing dyspepsia severe enough to necessitate discontinuation of NSAIDs.

G-protein beta3 subunit polymorphism and bleeding in the orbofiban in patients with unstable coronary syndromes-thrombolysis in myocardial infarction 16 trial

SUMMARY BACKGROUND

Variability in platelet response to antiplatelet drugs is heritable. A common single base substitution (825C>T) in the G-protein beta polypeptide 3 (GNB3) gene leads to alternative splicing (41-amino-acid deletion) of the human G-protein beta3 (Gbeta3) subunit. This truncated protein carried by GNB3 T allele carriers is linked to coronary artery disease and implicated as a genetic marker of drug response. Large studies of Caucasians associate T allele carriage with lower platelet reactivity.

OBJECTIVES

To evaluate whether the GNB3 genotype would predispose to bleeding in patients treated with a GPIIb/IIIa receptor antagonist.

METHODS

GNB3 genotype distribution was determined in DNA samples from patients in the orbofiban in patients with unstable coronary syndromes-thrombolysis in myocardial infarction (OPUS-TIMI) 16 genetic sub-study. Impact of genotype on the bleeding endpoint and the composite primary endpoint of death, myocardial infarction (MI), re-hospitalization for ischemia and urgent revascularization was estimated in the treatment and placebo arm.

RESULTS

Out of 887 patients, 45.1% carried the GNB3 CC genotype, 44.5% CT and 10.4% TT. Interaction between T allele carriership and treatment for bleeding was significant (P = 0.008). This reflects the fact that GNB3 non-T carriers treated with orbofiban had no bleeding effect compared with placebo (RR = 0.92, 95% CI 0.55-1.55) whereas T carriers did (RR = 2.62, 95% CI 1.58-4.35, P < 0.001). Interaction between T allele carriership and treatment was not significant for the primary endpoint (P = 0.18) or MI (P = 0.69).

CONCLUSION

The GNB3 T allele significantly increased bleeding in patients treated with the platelet antagonist orbofiban. Our findings suggest that risk of bleeding associated with an antiplatelet agent is heritable and may be dissociated from risk of thrombosis.

Influence of stroke subtype on quality of care in the Get With The Guidelines-Stroke Program

OBJECTIVE

Little is known about in-hospital care for hemorrhagic stroke. We examined quality of care in intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) admissions in the national Get With The Guidelines-Stroke (GWTG-Stroke) database, and compared them to ischemic stroke (IS) or TIA admissions.

METHODS

Between April 1, 2003, and December 30, 2007, 905 hospitals contributed 479,284 consecutive stroke and TIA admissions. The proportions receiving each quality of care measure were calculated by dividing the total number of patients receiving the intervention by the total number of patients eligible for the intervention, excluding ineligible patients or those with contraindications to treatment. Logistic regression models were used to determine associations between measure compliance and stroke subtype, controlling for patient and hospital characteristics.

RESULTS

Stroke subtypes were 61.7% IS, 23.8% TIA, 11.1% ICH, and 3.5% SAH. Performance on care measures was generally lower in ICH and SAH compared to IS/TIA, including guideline-recommended measures for deep venous thrombosis (DVT) prevention (for ICH) and smoking cessation (for SAH) (multivariable-adjusted p < 0.001 for all comparisons). Exceptions were that ICH patients were more likely than IS/TIA to have door-to-CT times <25 minutes (multivariable-adjusted p < 0.001) and to undergo dysphagia screening (multivariable-adjusted p < 0.001). Time spent in the GWTG-Stroke program was associated with improvements in many measures of care for ICH and SAH patients, including DVT prevention and smoking cessation therapy (multivariable-adjusted p < 0.001).

CONCLUSIONS

Many hospital-based acute care and prevention measures are underutilized in intracerebral hemorrhage and subarachnoid hemorrhage compared to ischemic stroke /TIA. Duration of Get With The Guidelines-Stroke participation is associated with improving quality of care for hemorrhagic stroke.

Prescription rates of protective co-therapy for NSAID users at high GI risk and results of attempts to improve adherence to guidelines

BACKGROUND

Protective co-therapy is recommended in NSAID users with GI risk factors, but adherence is poor.

AIM

To assess the proportion of NSAID users receiving co-therapy and strategies to improve adherence.

METHODS

Arthritis patients > or =50 years of age received etoricoxib or diclofenac in a double-blind randomized trial. Reminders that high-risk patients (age > or = 65; previous ulcer/haemorrhage; corticosteroid, anticoagulant, aspirin use) should receive co-therapy were given at study initiation. Free PPI was provided. An intervention midway through the study included a written reminder and required written response regarding co-therapy.

RESULTS

16,244/23,504 (69%) patients had GI risk factors. Pre-intervention, co-therapy was most common with previous ulcer/haemorrhage [706/1107 (64%)] and 3-4 risk factors [331/519 (64%)]. In the 10,026 patients enrolled pre-intervention and remaining in the study > or =6 months after, co-therapy in high-risk patients increased from 2958/6843 (43%) to 4177/6843 (61%) (difference = 18%; 95% CI 16%,19%). The increase was greater outside the US (22%; 19%,24%) than in the US (15%; 13%,17%).

CONCLUSIONS

Less than 50% of NSAID users with GI risk factors are given protective co-therapy--even if prescribers are given reminders and cost is not an issue. Direct communication requiring written response significantly increased adherence to guidelines, but achieving higher levels of adherence will require additional strategies.

Bleeding risk with AZD6140, a reversible P2Y12 receptor antagonist, vs. clopidogrel in patients undergoing coronary artery bypass grafting in the DISPERSE2 trial

AZD6140, the first reversible oral P2Y(12) receptor antagonist, exhibits greater and more consistent inhibition of platelet aggregation than the irreversible thienopyridine clopidogrel. As a result of its reversible effect, AZD6140 may pose less risk for bleeding when antiplatelet treatment cannot be stopped at least 5 days before coronary artery bypass graft (CABG) surgery or other invasive procedures. The Dose conflrmation Study assessing anti-Platelet Effects of AZD6140 vs. clopidogRel in NSTEMI (DISPERSE2) trial showed overall comparable bleeding rates with antiplatelet treatment with AZD6140 90 mg twice daily or 180 mg twice daily vs. clopidogrel 75 mg once daily in 984 patients with non-ST-elevation acute coronary syndromes. A post hoc exploratory analysis of bleeding outcomes in the subset of 84 patients undergoing CABG in DISPERSE2 suggests reduced risk for total bleeding (41% and 58% vs. 62%), all major bleeding (38% and 50% vs. 62%), and life-threatening bleeding (22% and 38% vs. 54%) with AZD6140 90 mg (n = 32) and 180 mg (n = 26) vs. clopidogrel (n = 26) respectively. Trends suggested that major bleeding rates were reduced with AZD6140 (combined groups) vs. clopidogrel when treatment was stopped < or = 5 days prior to surgery (39% vs. 63%, p = 0.15) but not when treatment was stopped > 5 days before surgery (50% vs. 60%). This observation is consistent with the reversible binding of AZD6140 to the P2Y(12) receptor. Further prospective studies are planned to assess the relationship between this potential clinical benefit of AZD6140 and the reversibility of its antiplatelet effects.

The role of cardiac troponin-I (cTnI) in risk stratification of patients with unstable coronary artery disease

In patients with chest pain at rest but no ST-segment elevation on the electrocardiogram, the diagnoses of unstable angina and non-Q-wave myocardial infarction (MI) are usually considered together because they cannot be differentiated clinically or angiographically. Since the extent of myocardial necrosis is an important determinant of the risk of death, it is important to identify serum markers with which to predict prognosis, in order to initiate appropriate medical treatment and/or invasive procedures in these patients. Cardiac troponin-I (cTnI), one of the subunits of the troponin regulatory complex, binds to actin and inhibits interactions between actin and myosin. The presence of elevated cTnI in serum is a significant prognostic indicator in patients with unstable angina and non-Q wave MI. Its independent prognostic potential persists even after adjustment for independent baseline variables known to be significantly associated with an increased risk of cardiac events. The use of cTnI in the triage of patients with unstable coronary disease may identify those at greater risk for adverse cardiac events.

Learning from the recently completed oral glycoprotein IIb/IIIa receptor antagonist trials

Although parenteral therapy with glycoprotein (GP) IIb/IIIa inhibitors has resulted in a reduced risk of death or myocardial infarction in patients with acute coronary syndromes and in patients undergoing percutaneous coronary intervention, the benefit is achieved only during the infusion period. Oral GP IIb/IIIa inhibitors may offer an opportunity to expand the application of this therapy to additional vascular indications and to extend therapy beyond the in-hospital period. A number of oral GP IIb/IIIa inhibiting agents have been evaluated; however, no benefit has been observed. Oral GP IIb/IIIa inhibitors have been associated with an increased incidence of bleeding, but additional experience may permit the design of dosing regimens that decrease this risk. The recent Orbofiban in Patients with Unstable Coronary Syndromes (OPUS/TIMI-16) trial showed a small but significant increase in mortality in orbofiban-treated patients. It appears that this agent, and perhaps other oral GP IIb/IIIa inhibitors including sibrafiban and xemilofiban, may have a pro-aggregatory effect. This may be caused by the drug dissociating from the GP IIb/IIIa receptor, leaving an activated receptor that can then bind fibrinogen and form a platelet aggregate. Further studies are needed to elucidate the mechanism of this effect and to evaluate whether the second-generation of oral GP IIb/IIIa inhibitors, which have tight binding and a longer duration of antiplatelet effect, will be of clinical benefit.

Prehospital thrombolysis: an idea whose time has come

Aggressive reperfusion therapy for myocardial infarction (MI) characterized by acute ST-segment elevation leads to improved patient outcome. Furthermore, use of thrombolytic therapy is highly time-dependent: reperfusion therapy is beneficial within 12 h, but the earlier it is administered, the more beneficial it is. Thus, the focus of both prehospital and emergency department management of patients with acute MI is on rapid identification and treatment. There are many components to the time delays between the onset of symptoms of acute MI and the achievement of reperfusion in the occluded infarct-related artery. Time delays occur with both the patient and the prehospital emergency medical system, although patient delays are more significant. This article focuses on the prehospital management of acute MI, including (1) the rationale for rapid reperfusion in patients with acute MI, (2) the factors related to time delays in patient presentation to the hospital, and (3) strategies for reducing time delays, both patient- and medical system-based.

Emergency department thrombolysis critical pathway reduces door-to-drug times in acute myocardial infarction

BACKGROUND

Rapid time to treatment with thrombolytic therapy is an important determinant of survival in acute myocardial infarction (AMI).

HYPOTHESIS

We hypothesized that establishment of an AMI thrombolysis critical pathway in the Emergency Department could successfully reduce the "door-to-drug" time, the time between patient arrival and start of thrombolysis.

METHODS AND RESULTS

Before establishment of the AMI critical pathway, median door-to-drug time was 73 min, which was reduced to 37 min after critical pathway implementation (p < 0.05). The percentage of patients treated within 30 min rose from 0% prior to establishment of the pathway to 43% (p = 0.03). Similarly, the percentage treated in within 45 min rose from 0 to 67% (p = 0.0005). Door-to-drug times were longer for women than for men (median 105 min for women vs. 70 min for men before pathway implementation). The pathway reduced door-to-drug time for both genders, but the median door-to-drug times were higher for women than for men (Mann-Whitney p = 0.013). The difference between men and women was 35 min before establishment of the pathway to 10 min by the end of the study period.

CONCLUSIONS

Our critical pathway was successful in reducing door-to-drug times. We observed a "gender gap" in door-to-drug times, with longer mean times for women, which was reduced by the AMI critical pathway. Thus, our data provide support for the use of critical pathways to reduce door-to-drug times, as recommended by the National Heart Attack Alert Program.

Combination therapy in the management of mixed dyslipidaemia

Whilst statin monotherapy is often sufficient to reach LDL-C goals, treatment may not reach all lipid goals in individuals with mixed dyslipidaemia typically associated with metabolic syndrome or type 2 diabetes. Double or triple combination therapy, which provides the opportunity to address multiple lipid abnormalities simultaneously, may be required to achieve targets in some patients. Addition of fenofibrate or niacin (nicotinic acid) to statin therapy is likely to be the first option, as recommended by national treatment guidelines; omega-3 fatty acids may also be useful. Careful monitoring is required when adding additional agents given the increased potential for drug interactions and side effects.

Myocardial infarction: contemporary management strategies

Myocardial infarction (MI) is a common clinical diagnosis, associated with significant morbidity and mortality, not only in the short term, but also years following the index event. A more complete understanding of the pathophysiology of MI has ushered the era of multipronged treatment approach, with a combination of goal-directed revascularization, a broad adjunctive pharmacological therapy and aggressive secondary prevention measures. The goals of this article are to review the basic pathophysiological processes, which lead up to a clinical diagnosis of MI, to highlight the essential elements of clinical presentation and to summarize the evidence for comprehensive therapy. Emphasis has been placed on the choice of primary reperfusion therapy for ST-elevation MI, on risk-stratification of patients with non-ST elevation MI, and on rationale behind the selection of anti-ischaemic and antithrombotic therapy. Finally, evidence-based approach to secondary prevention is outlined.

Recent trials of lipid lowering

The global burden of coronary artery disease has pushed lipid-lowering therapy to the forefront of medical management of this condition. Recent clinical trials have compared the efficacy of more intensive lipid lowering with statins against the normal standard of care. Other agents such as fibrates, glitazones, which also favourably modify lipid levels have also been assessed recently. This narrative review summarises the key recent clinical trials of lipid lowering since 2004 and their implications for future patient care.

Ischemic Preconditioning: Implications for the Geriatric Heart

Ischemic preconditioning is among the most consistent and powerful modes of reducing myocardial infarct size. Although several clinical studies have suggested that the human heart can be preconditioned, controversy exists in both the experimental and clinical literature as to whether the senescent heart can be preconditioned. The authors recently reported that older patients (> or = 60 years of age) in the Thrombolysis in Myocardial Infarction-4 study appeared to benefit from a history of angina prior to acute myocardial infarction. This observation may lead to a clinical counterpart to successful preconditioning in the older heart.

Influence of genetic variation in the C-reactive protein gene on the inflammatory response during and after acute coronary ischemia

The aim of this research was to assess whether common genetic variants within the C-reactive protein gene (CRP) are related to the degree of acute rise in plasma C-reactive protein (CRP) levels following an acute coronary syndrome (ACS). While polymorphisms within CRP are associated with basal CRP levels in healthy men and women, less is known about the relationship of such genetic variants and the degree of CRP rise during and after acute ischemia. Plasma CRP is associated with increased rates of recurrent coronary events. We evaluated seven common genetic variants within CRP and assessed their relationship to the degree of rise in CRP levels immediately following an acute coronary syndrome in 1827 European American patients. Variants in the putative promoter region, -757T > C and -286C > T > A, were associated with the highest CRP elevations after ACS. Patients with two copies of the A allele of SNP -286C > T > A had median CRP values of 76.6 mg/L, compared to 11.1 mg/L in patients with no copies of the rare variant (p-value <0.0001), post ACS. The lowest CRP values were found for patients with minor alleles of the exonic 1059G > C and the 3'untranslated region 1846G > A SNPs. For example, patients homozygous for the minor allele of 1059G > C had 71% lower median CRP values than those homozygous for the major allele [3.5 vs 12.0 mg/L, p < 0.0001]. These trends persisted in the chronic stable phase after ischemia had resolved, and after adjustment for infarct size by peak creatinine kinase levels and clinical status by Killip class. Assessment of CRP genetic variants identified patients with higher and lower CRP elevation after acute coronary syndrome.

The contribution of genetic factors to thrombotic and bleeding outcomes in coronary patients randomised to IIb/IIIa antagonists

Genetic variants are risk factors for coronary disease, but their role in recurrent events and in response to treatment is less clear. We genotyped genetic variants implicated in primary coronary disease in 924 Caucasians with acute coronary syndromes participating in the OPUS-TIMI16 trial of the GPIIb/IIIa antagonist orbofiban. These were the platelet glycoprotein (GP) receptors GPIIIa, GPIa, GPIbalpha; platelet ligands beta-fibrinogen and von Willebrand Factor (vWF); interleukins (IL) IL-1RN, and IL-6; adhesion proteins E-selectin and P-selectin; and metalloproteinase MMP-9. Cox modelling of all genetic variants demonstrated no significant impact on the composite endpoint (P = 0.88), which included myocardial infarction (MI), death, recurrent ischemia, urgent revascularisation and stroke, but a significant impact on recurrent myocardial infarction alone (chi(2) = 20.4, 10 df, P = 0.04). There was a significant interaction of the polymorphisms with orbofiban treatment influencing bleeding outcomes (P = 0.004). Thus, genetic polymorphisms may be associated with subsequent myocardial infarction, and may also be associated with treatment-associated bleeding among coronary patients.

"Hot" unstable angina--is it worse than subacute unstable angina? Results from the GUARANTEE Registry

BACKGROUND AND METHODS

Because time to presentation to the hospital affects time to treatment and is known to be important in acute myocardial infarction, we evaluated this variable in patients with unstable angina/non-ST segment elevation myocardial infarction (UA/NSTEMI). Among 2909 consecutive patients with UA/NSTEMI admitted to 35 hospitals in 6 geographic regions of the United States, we compared patients with acute (onset of pain <12 hours before admission) and subacute (onset >12 hours) unstable angina.

RESULTS

Patients with "hot" (acute) unstable angina presented more often to the emergency department and were subsequently admitted more often to an intensive care unit. Hospital administration of medications did not differ between the two groups, with the exception of heparin, which was paradoxically used more often in subacute patients (p<0.001). All cardiac invasive procedures were undertaken less often in the acute patients (catheterization, 41.4% vs. 58.7%, p=0.001; percutaneous coronary intervention, 11.3% vs. 21.1%, p=0.001; coronary artery bypass grafting, 5.6% vs. 12.0%, p=0.001). A greater percentage of acute patients were found to have no significant coronary artery disease at cardiac catheterization (20.1% vs. 15.0%, p=0.006). Mortality did not differ between the two groups; however, the composite endpoint of death and MI favored the acute patients (1.3% vs. 2.2%, p=0.032).

CONCLUSIONS

Contrary to our initial hypothesis, "hot" UA patients tended to be at lower risk than patients with subacute presentation, highlighting the fact that patients with UA/NSTEMI remain at high risk even after the initial 12-hour period.

Genetic variation in glycoprotein IIb/IIIa (GPIIb/IIIa) as a determinant of the responses to an oral GPIIb/IIIa antagonist in patients with unstable coronary syndromes

This study examined the influence of the Pl(A) polymorphism of glycoprotein IIIa (GPIIIa) in determining the response to an oral GPIIb/IIIa antagonist, orbofiban, in patients with unstable coronary syndromes. Genotyping for the Pl(A) polymorphism was performed in 1014 patients recruited into the OPUS-TIMI-16 (orbofiban in patients with unstable coronary syndromes-thrombolysis in myocardial infarction 16) trial, in which patients were randomized to low- or high-dose orbofiban or placebo for 1 year. The primary end point (n = 165) was a composite of death, myocardial infarction (MI), recurrent ischemia requiring rehospitalization, urgent revascularization, and stroke. Overall, orbofiban failed to reduce ischemic events when compared with placebo, but increased the rate of bleeding. In the whole population, Pl(A2) carriers had a significant increase in MI (n = 33) during follow up, with a relative risk (RR) of 2.71 (95% CI, 1.37 to 5.38; P =.004). There was a significant interaction between treatment (placebo and orbofiban) and the Pl(A) polymorphism for bleeding (n = 187; P =.05). Thus, while orbofiban increased bleeding in noncarriers (RR = 1.87, 1.29 to 2.71; P <.001) in a dose-dependent fashion, it did not increase bleeding events in Pl(A2) carriers (RR = 0.87, 0.46 to 1.64). There was no interaction between treatment (placebo and orbofiban) and the Pl(A) polymorphism for the primary end point (P =.10). However, in the patients receiving orbifiban there was a higher risk of a primary event (RR = 1.55, 1.03 to 2.34; P =.04) and MI (RR 4.27, 1.82 to 10.03; P <.001) in Pl(A2) carriers compared with noncarriers. In contrast, there was no evidence that Pl(A2) influenced the rate of recurrent events in placebo-treated patients. In patients presenting with an acute coronary syndrome, the Pl(A) polymorphism of GPIIb/IIIa may explain some of the variance in the response to an oral GPIIb/IIIa antagonist.

Ability of minor elevations of troponins I and T to predict benefit from an early invasive strategy in patients with unstable angina and non-ST elevation myocardial infarction: results from a randomized trial

CONTEXT

Cardiac troponins I (cTnI) and T (cTnT) are useful for assessing prognosis in patients with unstable angina and non-ST-segment elevation myocardial infarction (UA/NSTEMI). However, the use of cardiac troponins for predicting benefit of an invasive vs conservative strategy in this patient population is not clear.

OBJECTIVE

To prospectively test whether an early invasive strategy provides greater benefit than a conservative strategy in acute coronary syndrome patients with elevated baseline troponin levels.

DESIGN

Prospective, randomized trial conducted from December 1997 to June 2000.

SETTING

One hundred sixty-nine community and tertiary care hospitals in 9 countries.

PARTICIPANTS

A total of 2220 patients with acute coronary syndrome were enrolled. Baseline troponin level data were available for analysis in 1821, and 1780 completed the 6-month follow-up.

INTERVENTIONS

Patients were randomly assigned to receive (1) an early invasive strategy of coronary angiography between 4 and 48 hours after randomization and revascularization when feasible based on coronary anatomy (n = 1114) or (2) a conservative strategy of medical treatment and, if stable, predischarge exercise tolerance testing (n = 1106). Conservative strategy patients underwent coronary angiography and revascularization only if they manifested recurrent ischemia at rest or on provocative testing.

MAIN OUTCOME MEASURE

Composite end point of death, MI, or rehospitalization for acute coronary syndrome at 6 months.

RESULTS

Patients with a cTnI level of 0.1 ng/mL or more (n = 1087) experienced a significant reduction in the primary end point with the invasive vs conservative strategy (15.3% vs 25.0%; odds ratio [OR], 0.54; 95% confidence interval [CI], 0.40-0.73). Patients with cTnI levels of less than 0.1 ng/mL had no detectable benefit from early invasive management (16.0% vs 12.4%; OR, 1.4; 95% CI, 0.89-2.05; P<.001 for interaction). The benefit of invasive vs conservative management through 30 days was evident even among patients with low-level (0.1-0.4 ng/mL) cTnI elevation (4.4% vs 16.5%; OR, 0.24; 95% CI, 0.08-0.69). Directionally similar results were observed with cTnT.

CONCLUSION

In patients with clinically documented acute coronary syndrome who are treated with glycoprotein IIb/IIIa inhibitors, even small elevations in cTnI and cTnT identify high-risk patients who derive a large clinical benefit from an early invasive strategy.

Early coronary intervention following pharmacologic therapy for acute myocardial infarction (the combined TIMI 10B-TIMI 14 experience)

Earlier studies have suggested that immediate percutaneous coronary intervention (PCI) following thrombolytic therapy for acute myocardial infarction (AMI) is associated with an increase in adverse events and that routine PCI in this setting has offered no advantage over a conservative strategy. To reassess this issue in a more recent era, we evaluated 1,938 patients from the Thrombolysis in Myocardial Infarction (TIMI) 10B and 14 trials of AMI. Patients in TIMI 10B were randomized to receive tissue plasminogen activator or TNK tissue plasminogen activator, whereas patients in TIMI 14B trial were randomized to receive thrombolytic therapy with or without abciximab. All patients underwent angiography 90 minutes after receiving pharmacologic therapy. Patients who underwent PCI were classified as having undergone a rescue procedure (TIMI 0 or 1 flow at 90 minutes), an adjunctive procedure (TIMI 2 or 3 flow at 90 minutes), or a delayed procedure (performed >150 minutes after symptom onset, median of 2.75 days). Among patients with TIMI 0 or 1 flow, there was a trend for lower 30-day mortality among patients who underwent rescue PCI than among those who did not (6% vs 17%, p = 0.01, adjusted p = 0.28). Patients who underwent adjunctive PCI had similar 30-day mortality and/or reinfarction as those who underwent delayed PCI. In a multivariate model both had lower 30-day mortality and/or reinfarction than patients with "successful thrombolysis" (i.e., TIMI 3 flow at 90 minutes) who did not undergo revascularization (p = 0.02). Thus, early PCI following AMI is associated with excellent outcomes. Randomized trials of an early invasive strategy following thrombolysis are warranted.

The prognostic value of B-type natriuretic peptide in patients with acute coronary syndromes

BACKGROUND

Brain (B-type) natriuretic peptide is a neurohormone synthesized predominantly in ventricular myocardium. Although the circulating level of this neurohormone has been shown to provide independent prognostic information in patients with transmural myocardial infarction, few data are available for patients with acute coronary syndromes in the absence of ST-segment elevation.

METHODS

We measured B-type natriuretic peptide in plasma specimens obtained a mean (+/-SD) of 40+/-20 hours after the onset of ischemic symptoms in 2525 patients from the Orbofiban in Patients with Unstable Coronary Syndromes-Thrombolysis in Myocardial Infarction 16 study.

RESULTS

The base-line level of B-type natriuretic peptide was correlated with the risk of death, heart failure, and myocardial infarction at 30 days and 10 months. The unadjusted rate of death increased in a stepwise fashion among patients in increasing quartiles of base-line B-type natriuretic peptide levels (P< 0.001). This association remained significant in subgroups of patients who had myocardial infarction with ST-segment elevation (P=0.02), patients who had myocardial infarction without ST-segment elevation (P<0.001), and patients who had unstable angina (P<0.001). After adjustment for independent predictors of the long-term risk of death, the odds ratios for death at 10 months in the second, third, and fourth quartiles of B-type natriuretic peptide were 3.8 (95 percent confidence interval, 1.1 to 13.3), 4.0 (95 percent confidence interval, 1.2 to 13.7), and 5.8 (95 percent confidence interval, 1.7 to 19.7). The level of B-type natriuretic peptide was also associated with the risk of new or recurrent myocardial infarction (P=0.01) and new or worsening heart failure (P<0.001) at 10 months.

CONCLUSIONS

A single measurement of B-type natriuretic peptide, obtained in the first few days after the onset of ischemic symptoms, provides powerful information for use in risk stratification across the spectrum of acute coronary syndromes. This finding suggests that cardiac neurohormonal activation may be a unifying feature among patients at high risk for death after acute coronary syndromes.

Application of the TIMI risk score for ST-elevation MI in the National Registry of Myocardial Infarction 3

CONTEXT

The Thrombolysis in Myocardial Infarction (TIMI) risk score for ST-elevation myocardial infarction (STEMI) is a simple integer score for bedside risk assessment of patients with STEMI. Developed and validated in multiple clinical trials of fibrinolysis, the risk score has not been validated in a community-based population.

OBJECTIVE

To validate the TIMI risk score in a population of STEMI patients reflective of contemporary practice.

DESIGN, SETTING, AND PARTICIPANTS

The risk score was evaluated among 84 029 patients with STEMI from the National Registry of Myocardial Infarction 3 (NRMI 3), which collected data on consecutive patients with myocardial infarction (MI) from 1529 US hospitals between April 1998 and June 2000.

MAIN OUTCOME MEASURES

Ability of the TIMI risk score to correctly predict risk of death in terms of model discrimination (c statistic) and calibration (agreement of predicted and observed death rates).

RESULTS

Patients in NRMI 3 tended to be older, to be more often female, and to have a history of coronary disease more often than those in the derivation set. Forty-eight percent received reperfusion therapy. The TIMI risk score revealed a significant graded increase in mortality with rising score (range, 1.1%-30.0%; P<.001 for trend). The risk score showed strong prognostic capacity overall (c = 0.74 vs 0.78 in derivation set) and among patients receiving acute reperfusion therapy (c = 0.79). Predictive behavior of the risk score was similar between fibrinolytic-treated patients (n = 23 960; c = 0.79) and primary percutaneous coronary intervention patients (n = 15 348; c = 0.80). In contrast, among patients not receiving reperfusion therapy, the risk score underestimated death rates and offered lower discriminatory capacity (c = 0.65).

CONCLUSIONS

Sufficiently simple to be practical at the bedside and effective for risk assessment across a spectrum of patients, the TIMI risk score may be useful in triage and treatment of patients with STEMI who are treated with reperfusion therapy.

The platelet Pl(A2) and angiotensin-converting enzyme (ACE) D allele polymorphisms and the risk of recurrent events after acute myocardial infarction

Chromosome 17q21-23 harbors genes for platelet glycoprotein IIIa and angiotensin-converting enzyme (ACE), which are polymorphic for alleles Pl(A2) and ACE "D." These alleles have been independently and often associated with ischemic coronary artery disease (CAD). We sought to determine if the Pl(A2) and ACE D polymorphisms were risk factors for recurrent coronary events. In the Cholesterol And Recurrent Events (CARE) trial, 4,159 men and women with documented myocardial infarction (MI) were randomized to receive either placebo or pravastatin, and were followed prospectively for 5 years. Pl(A) and ACE genotypes were determined in 767 patients: 385 cases who had experienced a recurrent primary event (death due to coronary disease or nonfatal MI), and 382 age- and gender-matched controls. In patients receiving placebo, the Pl(A1,A2) genotype conferred a relative risk (RR) of 1.38 (confidence intervals [CI] 1.04 to 1.83; p = 0.028; adjusted RR = 1.32, CI = 0.99 to 1.76; p = 0.058]) for the primary end point. Compared with the placebo group, pravastatin reduced the excess RR of coronary disease death and recurrent MI in the Pl(A1,A2) patient population by 31% (p = 0.06). The ACE D allele appeared to have modestly additive effects on the Pl(A1,A2) risk. Among the Pl(A1,A2) patients, pravastatin had little effect on the risk of recurrent events with the ACE II genotype, but reduced the adjusted RR from 1.42 (placebo) to 0.58 for ACE ID patients, and from 1.56 (placebo) to 0.83 for ACE DD. The Pl(A1,A2) genotype was associated with an excess of recurrent coronary events in patients after MI who did not receive pravastatin, and the ACE D allele added to this risk. These data suggest that it would be important to perform a larger study to address the potential role of these genotypes in therapeutic decision making.

Early noninvasive detection of failed epicardial reperfusion after fibrinolytic therapy

Available noninvasive techniques for identifying patients with failed epicardial reperfusion after fibrinolytic therapy are limited by poor accuracy. It is unknown whether combining multiple noninvasive predictors would improve diagnostic accuracy and facilitate identification of candidates for rescue percutaneous coronary intervention. In the Thrombolysis In Myocardial Infarction (TIMI) 14 trial, we evaluated the ability of ST-segment resolution (n = 606), chest pain resolution (n = 859), and the ratio of 60-minute/baseline serum myoglobin (n = 308) to identify patients with angiographic evidence of failed reperfusion 90 minutes after fibrinolysis. Three criteria were prospectively defined: <50% ST resolution at 90 minutes, presence of chest pain at the time of angiography, and myoglobin ratio <4. Patients who met any individual criterion were more likely to have less than TIMI 3 flow and an occluded infarct-related artery (TIMI 0/1 flow) than those who did not meet the criterion (p <0.005 for each). When the 3 criteria were used together (n = 169), patients who satisfied 0 (n = 29), 1 (n = 68), 2 (n = 51), or 3 (n = 21) of the criteria had a 17%, 24%, 35%, and 76% probability of failing to achieve TIMI 3 flow (p <0.0001 for trend), a 0%, 6%, 18%, and 57% probability of an occluded infarct-related artery (p <0.0001 for trend), and a 0%, 1.5%, 2.0%, and 9.5% rate of 30-day mortality (p = 0.05 for trend), respectively. Use of the criteria in combination increased positive predictive values without decreasing negative predictive values. In conclusion, ST-segment resolution, chest pain resolution, and early washout of serum myoglobin can be used in combination to aid in the early noninvasive identification of candidates for rescue percutaneous coronary intervention.

Myoglobin levels at 12 hours identify patients at low risk for 30-day mortality after thrombolysis in acute myocardial infarction: a Thrombolysis in Myocardial Infarction 10B substudy

OBJECTIVE

We sought to identify, by use of serum cardiac markers, patients at low risk for 30-day mortality after ST-segment elevation myocardial infarction.

BACKGROUND

Baseline cardiac markers are currently used to identify patients at increased risk for short-term events. We hypothesized that serum markers measured after treatment could identify patients at low risk for 30-day mortality.

METHODS

A total of 839 patients from the Thrombolysis in Myocardial Infarction (TIMI) 10B study had myoglobin, cardiac-specific troponin-I, creatine kinase (CK)-MB measurements at the following time points; baseline, 90 minutes, and 3 and 12 hours after thrombolysis. By use of receiver operating characteristic analysis, thresholds were derived to predict 30-day mortality with at least 95% negative predictive value.

RESULTS

Ninety minutes after thrombolysis myoglobin was superior to troponin-I or CK-MB in identifying patients at low risk for mortality. The 30-day mortality for 12-hour myoglobin < or = 239 ng/mL was 1.4% compared with 9.1% for levels > 239 ng/mL (P < .001). For 12-hour troponin-I (threshold 81.5 ng/mL), mortality was 1.9% versus 6.6% (P = .001) if above threshold; similarly for CK-MB at 12 hours (threshold 191 ng/mL) it was 3.3% versus 7.9% (P = .02). Multivariate analysis of baseline and posttreatment cardiac markers, age, sex, infarct artery location, and 90-minute TIMI flow grade identified only 12-hour myoglobin among the cardiac markers as independently predicting a low 30-day mortality (odds ratio 0.11, 95% confidence interval 0.02-0.50, P < .004).

CONCLUSION

Serum cardiac markers can identify greater than two thirds of patients at low risk for 30-day mortality. A low 12-hour myoglobin level (< or = 239 ng/mL in this substudy) identifies such patients at low risk and could potentially assist in early risk stratification and triage after ST-segment elevation myocardial infarction.

Comparison of early invasive and conservative strategies in patients with unstable coronary syndromes treated with the glycoprotein IIb/IIIa inhibitor tirofiban

BACKGROUND

There is continued debate as to whether a routine, early invasive strategy is superior to a conservative strategy for the management of unstable angina and myocardial infarction without ST-segment elevation.

METHODS

We enrolled 2220 patients with unstable angina and myocardial infarction without ST-segment elevation who had electrocardiographic evidence of changes in the ST segment or T wave, elevated levels of cardiac markers, a history of coronary artery disease, or all three findings. All patients were treated with aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban. They were randomly assigned to an early invasive strategy, which included routine catheterization within 4 to 48 hours and revascularization as appropriate, or to a more conservative (selectively invasive) strategy, in which catheterization was performed only if the patient had objective evidence of recurrent ischemia or an abnormal stress test. The primary end point was a composite of death, nonfatal myocardial infarction, and rehospitalization for an acute coronary syndrome at six months.

RESULTS

At six months, the rate of the primary end point was 15.9 percent with use of the early invasive strategy and 19.4 percent with use of the conservative strategy (odds ratio, 0.78; 95 percent confidence interval, 0.62 to 0.97; P=0.025). The rate of death or nonfatal myocardial infarction at six months was similarly reduced (7.3 percent vs. 9.5 percent; odds ratio, 0.74; 95 percent confidence interval, 0.54 to 1.00; P<0.05).

CONCLUSIONS

In patients with unstable angina and myocardial infarction without ST-segment elevation who were treated with the glycoprotein IIb/IIIa inhibitor tirofiban, the use of an early invasive strategy significantly reduced the incidence of major cardiac events. These data support a policy involving broader use of the early inhibition of glycoprotein IIb/IIIa in combination with an early invasive strategy in such patients.

Combination therapy with abciximab reduces angiographically evident thrombus in acute myocardial infarction: a TIMI 14 substudy

BACKGROUND

Use of abciximab in combination with administration of thrombolytics has been shown to improve epicardial and microvascular coronary blood flow in acute myocardial infarction (AMI). As a potential mechanism, we hypothesized that combination therapy would reduce angiographically evident thrombus (AET) and would increase lumen diameter compared with thrombolytic monotherapy.

METHODS AND RESULTS

Patients who received combination therapy in TIMI 14 (low-dose thrombolytic plus abciximab, n=732) were compared with patients who received thrombolytic monotherapy without abciximab in the TIMI 4, 10A, 10B, and 14 trials (n=1662). Thrombus burden was assessed 90 minutes after treatment, and quantitative angiography was performed in an angiographic core laboratory by investigators blinded to treatment assignment. The frequency of AET was reduced in patients who received abciximab combination therapy compared with thrombolytic monotherapy (26.6% versus 35.4%, P<0.001). Similar findings were observed when the analysis was restricted to patients with patent arteries (14.7% versus 20.8%, P=0.001). Residual percent diameter stenosis at 90 minutes was also improved in the abciximab therapy group both in patent arteries (64.6+/-16.6 versus 68.3+/-14.8, P<0.001) and between patent and occluded arteries (69.3+/-19.5 versus 73.8+/-17.9, P<0.001). The absence of AET was associated with an increased frequency of >70% ST-segment resolution by 90 minutes (37.2%, 110/296 versus 18.9%, 54/286, P<0.001).

CONCLUSIONS

Compared with thrombolytic monotherapy, combination therapy with abciximab reduces AET, which in turn is associated with reduced residual stenosis and improved ST-segment resolution in AMI. These data provide a pathophysiological link between platelet inhibition, reduced thrombus, and improvements in both epicardial and microvascular perfusion in AMI.