Axel Åkerblom

Comparison of ticagrelor, the first reversible oral P2Y12 receptor antagonist, with clopidogrel in patients with acute coronary syndromes: Rationale, design, and baseline characteristics of the PLATelet inhibition and patient Outcomes (PLATO) trial

BACKGROUND Antiplatelet therapy is essential treatment for acute coronary syndromes (ACS). Current therapies, however, have important limitations affecting their clinical success. Ticagrelor, the first reversible oral P2Y(12) receptor antagonist, provides faster, greater, and more consistent adenosine diphosphate-receptor inhibition than clopidogrel. The phase III PLATelet inhibition and patient Outcomes (PLATO) trial is designed to test the hypothesis that ticagrelor compared with clopidogrel will result in a lower risk of recurrent thrombotic events in a broad patient population with ACS. METHODS PLATO is an international, randomized, double-blind, event-driven trial involving >18,000 patients hospitalized for ST-elevation ACS with scheduled primary percutaneous coronary intervention or for non-ST-elevation ACS. After loading doses of ticagrelor 180 mg or clopidogrel 300 mg in a double-blind, double-dummy fashion (with provision for additional 300 mg clopidogrel at percutaneous coronary intervention), patients will receive ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily for 6 to 12 months on top of acetylsalicylic acid. The primary efficacy end point is time to first occurrence of death from vascular causes, myocardial infarction, or stroke. The primary safety variable is PLATO-defined major bleeding. An extensive substudy program will explore the pathophysiology of ACS, indicators of prognosis and response to treatment, mechanisms of effect and safety of the study medications, health economics, and quality of life. CONCLUSION The PLATO study will provide a pivotal comparison of the efficacy and safety of ticagrelor with those of clopidogrel in ACS patients, together with extensive information on treatment outcomes in different subsets of ACS in a broad patient population.

Eptifibatide Is Noninferior to Abciximab in Primary Percutaneous Coronary Intervention: Results From the SCAAR (Swedish Coronary Angiography and Angioplasty Registry)

OBJECTIVES The aim of this study was to test the noninferiority of eptifibatide relative to abciximab in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). BACKGROUND Glycoprotein IIb/IIIa inhibitors are recommended by international guidelines in patients with acute coronary syndromes undergoing PCI. Abciximab is recommended with a higher level of evidence than eptifibatide in patients with STEMI. No large, prospective, randomized trial comparing abciximab and eptifibatide has been published. METHODS All (n = 11,479) STEMI patients in Sweden who underwent primary PCI and received either eptifibatide or abciximab from 2004 to 2007 were derived from the SCAAR (Swedish Coronary Angiography and Angioplasty Registry). The primary end point was death or myocardial infarction (MI) during 1-year follow-up, with adjustment for baseline differences with a multivariate logistic regression analysis including propensity score. The pre-specified noninferiority margin was set to 1.29. RESULTS The combined end point occurred in 353 of 2,355 patients (15.0%) treated with eptifibatide and in 1,432 of 9,124 patients (15.7%) treated with abciximab. The unadjusted odds ratio (OR) for eptifibatide versus abciximab was 0.95 (95% confidence interval [CI]: 0.84 to 1.08). Multivariate adjustment (n = 11,317) confirmed noninferiority, with an OR of 0.94 (95% CI: 0.82 to 1.09). The adjusted secondary end points of death and MI separately also showed noninferiority, with ORs of 0.99 (95% CI: 0.82 to 1.19) and 0.88 (95% CI: 0.73 to 1.05), respectively. CONCLUSIONS This large registry study suggests that eptifibatide is noninferior to abciximab in patients with STEMI undergoing primary PCI with respect to death or MI during 1 year, thereby supporting the use of either drug in clinical practice.

Effect of genetic variations on ticagrelor plasma levels and clinical outcomes

AIMS Ticagrelor, a direct-acting P2Y12-receptor antagonist, is rapidly absorbed and partly metabolized to the major metabolite AR-C124910XX (ARC). To identify single-nucleotide polymorphisms (SNPs) associated with pharmacokinetics of ticagrelor and clinical outcomes, we performed a genome-wide association study (GWAS) in patients treated with ticagrelor in the PLATO trial. METHODS AND RESULTS A two-stage design was used for the GWAS with discovery (discovery phase: n = 1812) and replication cohorts (replication phase: n = 1941). The steady-state area under the curve (AUCss) values, estimated by the population pharmacokinetic (PK) models, were log transformed and analysed on a genome-wide scale using linear regression. SNPs were analysed against clinical events using Cox-regression in 4990 patients. An SNP (rs113681054) in SLCO1B1 was associated with levels of ticagrelor (P = 1.1 × 10(-6)) and ARC (P = 4.6 × 10(-13)). This SNP is in linkage disequilibrium with a functional variant (rs4149056) that results in decreased OATP1B1 transporter activity. Ticagrelor levels were also associated with two independent SNPs (rs62471956, P = 7.7 × 10(-15) and rs56324128, P = 9.7 × 10(-12)) in the CYP3A4 region. Further, ARC levels were associated with rs61361928 (P = 3.0 × 10(-14)) in UGT2B7. At all loci, the effects were small. None of the identified SNPs that affected ticagrelor PK were associated with the primary composite outcome (cardiovascular death myocardial infarction, and stroke), non-CABG-related bleeds or investigator-reported dyspnoea. CONCLUSION In patients with ACS, ticagrelor pharmacokinetics is influenced by three genetic loci (SLCO1B1, UGT2B7, and CYP3A4). However, the modest genetic effects on ticagrelor plasma levels did not translate into any detectable effect on efficacy or safety during ticagrelor treatment. CLINICAL TRIAL REGISTRATION NCT00391872.

Cystatin C and Estimated Glomerular Filtration Rate as Predictors for Adverse Outcome in Patients with ST-Elevation and Non–ST-Elevation Acute Coronary Syndromes: Results from the Platelet Inhibition and Patient Outcomes Study

BACKGROUND We evaluated the predictive ability of cystatin C and creatinine-based estimations of glomerular filtration rate (eGFR), including the Chronic Kidney Disease-Epidemiology (CKD-EPI) equation, in acute coronary syndrome (ACS) patients with (STE-ACS) or without (NSTE-ACS) ST elevation in a large contemporary ACS population. METHODS Concentrations of cystatin C and creatinine, as well as eGFR at randomization, were measured in 16 401 patients in the Platelet Inhibition and Patient Outcomes (PLATO) study and evaluated as predictors of the composite end point of cardiovascular death or myocardial infarction within 1 year. Two Cox proportional hazards models were used, the first adjusting for clinical characteristics and the second for clinical characteristics plus the biomarkers N-terminal pro-B-type natriuretic peptide, troponin I, and C-reactive protein. RESULTS The median cystatin C value was 0.83 mg/L. Increasing quartiles of cystatin C were strongly associated with poor outcome (6.9%, 7.1%, 9.5%, and 16.2%). The fully adjusted hazard ratios per SD of cystatin C in the NSTE-ACS and STE-ACS populations were 1.12 (95% CI 1.04-1.20) (n=8053) and 1.06 (95% CI 0.97-1.17) (n=5278), respectively. There was no significant relationship of cystatin C with type of ACS (STE or NSTE). c Statistics ranged from 0.6923 (cystatin C) to 0.6941 (CKD-EPI). CONCLUSIONS Cystatin C concentration contributes independently in predicting the risk of cardiovascular death or myocardial infarction in NSTE-ACS, with no interaction by type of ACS. CKD-EPI exhibited the largest predictive value of all renal markers. Nevertheless, the additive predictive value of cystatin C or creatinine-based eGFR measures in the unselected ACS patient is small.

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers in Myocardial Infarction Patients With Renal Dysfunction

BACKGROUND There is no consensus whether angiotensin-converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) should be used for secondary prevention in all or in only high-risk patients after an acute myocardial infarction (AMI). OBJECTIVES This study sought to investigate whether ACEI/ARB treatment after AMI is associated with better outcomes across different risk profiles, including the entire spectrum of estimated glomerular filtration rates. METHODS This study evaluated discharge and continuous follow-up data on ACEI/ARB use among AMI survivors (2006 to 2009) included in a large Swedish registry. The association between ACEI/ARB treatment and outcomes (mortality, myocardial infarction, stroke, and acute kidney injury [AKI]) was studied using Cox proportional hazards models (intention-to-treat and as treated). RESULTS In total, 45,697 patients (71%) were treated with ACEI/ARB. The 3-year mortality was 19.8% (17.4% of ACEI/ARB users and 25.4% of nonusers). In adjusted analysis, significantly better survival was observed for patients treated with ACEI/ARB (3-year hazard ratio: 0.80; 95% confidence interval: 0.77 to 0.83). The survival benefit was consistent through all kidney function strata, including dialysis patients. Overall, those treated with ACEI/ARB also had lower 3-year risk for myocardial infarction (hazard ratio: 0.91; 95% confidence interval: 0.87 to 0.95), whereas treatment had no significant effect on stroke risk. The crude risk for AKI was in general low (2.5% and 2.0% for treated and nontreated, respectively) and similar across estimated glomerular filtration rate categories but was significantly higher with ACEI/ARB treatment. However, the composite outcome of AKI and mortality favored ACEI/ARB treatment. CONCLUSIONS Treatment with ACEI/ARB after AMI was associated with improved long-term survival, regardless of underlying renal function, and was accompanied by low rates of adverse renal events.

Outcome after percutaneous coronary intervention for different indications : Long-term results from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR)

AIMS The aim of this study was to evaluate clinical outcome for different indications for PCI in an unselected, nationwide PCI population at short- and long-term follow-up. METHODS AND RESULTS We evaluated clinical outcome up to six years after PCI in all patients undergoing a PCI procedure for different indications in Sweden between 2006 and 2010. A total of 70,479 patients were treated for stable coronary artery disease (CAD) (21.0%), unstable angina (11.0%), non-ST-elevation myocardial infarction (NSTEMI) (36.6%) and ST-elevation myocardial infarction (STEMI) (31.4%). Mortality was higher in STEMI patients at one year after PCI (9.6%) compared to NSTEMI (4.7%), unstable angina (2.2%) and stable CAD (2.0%). At one year after PCI until the end of follow-up, the adjusted mortality risk (one to six years after PCI) and the risk of myocardial infarction were comparable between NSTEMI and STEMI patients and lower in patients with unstable angina and stable CAD. The adjusted risk of stent thrombosis and heart failure was highest in STEMI patients. CONCLUSIONS The risk of short-term mortality, heart failure and stent thrombosis is highest for STEMI patients after PCI. Therapies to reduce stent thrombosis and heart failure appear to be most important in decreasing mortality in patients with STEMI or NSTEMI undergoing PCI.

Cystatin C– and Creatinine-Based Estimates of Renal Function and Their Value for Risk Prediction in Patients with Acute Coronary Syndrome: Results from the PLATelet Inhibition and Patient Outcomes (PLATO) Study

BACKGROUND The estimated glomerular filtration rate (eGFR) independently predicts cardiovascular death or myocardial infarction (MI) and can be estimated by creatinine and cystatin C concentrations. We evaluated 2 different cystatin C assays, alone or combined with creatinine, in patients with acute coronary syndrome. METHODS We analyzed plasma cystatin C, measured with assays from Gentian and Roche, and serum creatinine in 16 279 patients from the PLATelet Inhibition and Patient Outcomes (PLATO) trial. We evaluated Pearson correlation and agreement (Bland-Altman) between methods, as well as prognostic value in relation to cardiovascular death or MI during 1 year of follow up by multivariable logistic regression analysis including clinical variables, biomarkers, c-statistics, and relative integrated discrimination improvement (IDI). RESULTS Median cystatin C concentrations (interquartile intervals) were 0.83 (0.68-1.01) mg/L (Gentian) and 0.94 (0.80-1.14) mg/L (Roche). Overall correlation was 0.86 (95% CI 0.85-0.86). The level of agreement was within 0.39 mg/L (2 SD) (n = 16 279). The areas under the curve (AUCs) in the multivariable risk prediction model with cystatin C (Gentian, Roche) or Chronic Kidney Disease Epidemiology Collaboration eGFR (CKD-EPI) added were 0.6914, 0.6913, and 0.6932. Corresponding relative IDI values were 2.96%, 3.86%, and 4.68% (n = 13 050). Addition of eGFR by the combined creatinine-cystatin C equation yielded AUCs of 0.6923 (Gentian) and 0.6924 (Roche) with relative IDI values of 3.54% and 3.24%. CONCLUSIONS Despite differences in cystatin C concentrations, overall correlation between the Gentian and Roche assays was good, while agreement was moderate. The combined creatinine-cystatin C equation did not outperform risk prediction by CKD-EPI.

Polymorphism of the cystatin C gene in patients with acute coronary syndromes: Results from the PLATelet inhibition and patient Outcomes study

PURPOSE Elevated cystatin C concentration is an independent risk factor for cardiovascular (CV) events in patients with acute coronary syndromes. Genetic polymorphisms in CST3 influence cystatin C levels, but their relationship to outcomes is unclear. METHODS We measured cystatin C concentrations in plasma, obtained within 24 hours of admission, in 16,279 acute coronary syndrome patients from the PLATO trial. In 9,978 patients, we performed a genome-wide association study with up to 2.5 million single nucleotide polymorphisms. Single nucleotide polymorphisms affecting cystatin C levels were evaluated in relation to the first occurrence of myocardial infarction (MI) or CV death within 1 year using Cox regression analysis. RESULTS Several single nucleotide polymorphisms were associated with cystatin C levels, most significantly rs6048952 (P = 7.82 × 10(-16)) adjacent to CST3. Median cystatin C concentrations per genotype were 0.85 mg/L (A/A), 0.80 mg/L (A/G), and 0.73 mg/L (G/G). Modeled as additive, the allelic effect, multivariable adjusted, was -0.045 mg/L per G allele for rs6048952. The multivariable adjusted c-statistic regarding the combined end point (CV death or MI) was 0.6735. Adding cystatin C or genotype-adjusted cystatin C levels resulted in c-statistics of 0.6761 and 0.6758, respectively. The multivariable adjusted hazard ratios per G allele at rs6048952 in the entire population were 0.94 (95% CI 0.83-1.06) for CV death or MI and 0.88 (95% CI 0.71-1.08) for CV death. CONCLUSIONS Genetic polymorphisms affect cystatin C concentrations independently of kidney function. However, the polymorphisms were not observed to be associated with outcome, nor did they improve risk prediction or discriminative models.

TICAGRELOR PLASMA LEVELS BUT NOT CLINICAL OUTCOMES ARE ASSOCIATED WITH TRANSPORTER AND METABOLISM ENZYME GENETIC POLYMORPHISMS

In the PLATO trial ticagrelor was superior to clopidogrel in reducing ischemic outcome and death in patients with acute coronary syndromes (ACS). Ticagrelor is a direct-acting P2Y12 receptor antagonist that is rapidly absorbed and partly metabolized to the major metabolite AR-C124910XX (ARC). ARC is

An examination of the relationship between serum uric acid level, a clinical history of gout, and cardiovascular outcomes among patients with acute coronary syndrome

Background Studies have suggested a relationship between higher baseline serum uric acid (sUA) levels and an elevated risk of subsequent ischemic cardiovascular outcomes among acute coronary syndrome (ACS) patients; this relationship may be modified by a clinical history of gout and has not been studied in large patient cohorts. We sought to understand the effect of sUA and gout on ACS outcomes. Methods Using PLATO and TRACER data on 27,959 ACS patients, we evaluated baseline sUA levels in relation to a composite of cardiovascular death, myocardial infarction (MI), or stroke. We assessed interaction terms to determine if a baseline clinical diagnosis of gout modified this putative relationship; 46% (n = 12,882) had sUA levels elevated >6.0 mg/dL. Results Patients with elevated levels were more often male with a history of prior MI, diabetes, and heart failure compared with those with sUA <6.0 mg/dL. The unadjusted risk of the composite endpoint increased with corresponding elevations in sUA levels (per 1 mg/dL increase) (HR = 1.23 [95% CI: 1.20–1.26]) above the statistical inflection point of 5.0 mg/dL. After adjustment, the association between sUA level and the composite outcome remained significant (HR = 1.07 [95% CI: 1.04–1.10]), and baseline gout did not modify this relationship. Conclusions In patients with ACS, increasing levels of sUA are associated with an elevated risk of cardiovascular events, regardless of a clinical diagnosis of gout. Further investigation is warranted to determine the mechanism behind this relationship and to delineate whether sUA is an appropriate therapeutic target to reduce cardiovascular risk.