Nils Åsenblad

Ticagrelor Versus Clopidogrel in Patients With Acute Coronary Syndromes Undergoing Coronary Artery Bypass Surgery Results From the PLATO (Platelet Inhibition and Patient Outcomes) Trial

OBJECTIVES The purpose of this study is to evaluate the efficacy and safety of ticagrelor and clopidogrel in patients with acute coronary syndrome undergoing coronary artery bypass graft surgery (CABG), as a post-randomization strategy. BACKGROUND Ticagrelor is a novel, reversibly binding, oral, direct-acting P2Y(12)-receptor antagonist. In the PLATO (Platelet Inhibition and Patient Outcomes) trial, which randomized 18,624 patients with acute coronary syndromes, ticagrelor compared with clopidogrel significantly reduced the risk of the primary composite end point of cardiovascular (CV) death, myocardial infarction, or stroke (hazard ratio [HR]: 0.84; 95% confidence interval [CI]: 0.77 to 0.92; p < 0.001). This report investigated the outcomes of patients treated with CABG during the trial. METHODS In total, 1,899 patients underwent CABG post-randomization. The protocol recommended ticagrelor/placebo to be withheld for 24 to 72 h and clopidogrel/placebo for 5 days preoperatively. In all, 1,261 patients underwent CABG and were receiving study drug treatment <7 days before surgery. The statistical analysis was based on events occurring from the CABG procedure until the end of the study, excluding 3 patients with CABG after study end. RESULTS In the 1,261 patient cohort, the relative reduction of primary composite end point at 12 months (10.6% [66 of 629] with ticagrelor versus 13.1% [79 of 629] with clopidogrel; HR: 0.84; 95% CI: 0.60 to 1.16; p = 0.29) was consistent with the results of the whole trial. Total mortality was reduced from 9.7% (58 of 629) to 4.7% (29 of 629; HR: 0.49; 95% CI: 0.32 to 0.77; p < 0.01), CV death from 7.9% (47 of 629) to 4.1% (25 of 629; HR: 0.52; 95% CI: 0.32 to 0.85; p < 0.01), and non-CV death numerically from 2.0% to 0.7% (p = 0.07). There was no significant difference in CABG-related major bleeding between the randomized treatments. CONCLUSIONS In the subgroup of patients undergoing CABG within 7 days after the last study drug intake, ticagrelor compared with clopidogrel was associated with a substantial reduction in total and CV mortality without excess risk of CABG-related bleeding.

Factors contributing to the lower mortality with ticagrelor compared with clopidogrel in patients undergoing coronary artery bypass surgery.

OBJECTIVES This study investigated the differences in specific causes of post-coronary artery bypass graft surgery (CABG) deaths in the PLATO (Platelet Inhibition and Patient Outcomes) trial. BACKGROUND In the PLATO trial, patients assigned to ticagrelor compared with clopidogrel and who underwent CABG had significantly lower total and cardiovascular mortality. METHODS In the 1,261 patients with CABG performed within 7 days after stopping study drug, reviewers blinded to treatment assignment classified causes of death into subcategories of vascular and nonvascular, and specifically identified bleeding or infection events that either caused or subsequently contributed to death. RESULTS Numerically more vascular deaths occurred in the clopidogrel versus the ticagrelor group related to myocardial infarction (14 vs. 10), heart failure (9 vs. 6), arrhythmia or sudden death (9 vs. 3), and bleeding, including hemorrhagic stroke (7 vs. 2). Clopidogrel was also associated with an excess of nonvascular deaths related to infection (8 vs. 2). Among factors directly causing or contributing to death, bleeding and infections were more common in the clopidogrel group compared with the ticagrelor group (infections: 16 vs. 6, p < 0.05, and bleeding: 27 vs. 9, p < 0.01, for clopidogrel and ticagrelor, respectively). CONCLUSIONS The mortality reduction with ticagrelor versus clopidogrel following CABG in the PLATO trial was associated with fewer deaths from cardiovascular, bleeding, and infection complications. (Platelet Inhibition and Patient Outcomes [PLATO]; NCT00391872).

Lower mortality following pulmonary adverse events and sepsis with ticagrelor compared to clopidogrel in the PLATO study

Abstract In the PLATelet inhibition and patient Outcomes (PLATO) study of patients with acute coronary syndromes, ticagrelor reduced mortality compared to clopidogrel but the mechanisms for this mortality reduction remain uncertain. We analysed adverse events (AEs) consistent with either pulmonary infection or sepsis, and subsequent mortality, in 18,421 PLATO patients treated with ticagrelor or clopidogrel. AEs occurring within 7 days of last dose of study medication were defined as “on-treatment”. Serial measurements of blood leukocyte counts, C-reactive protein and interleukin-6 were performed. Fewer on-treatment pulmonary AEs occurred in the ticagrelor compared to the clopidogrel group (275 vs. 331 respectively; p = 0.019), with fewer deaths following these AEs (33 vs. 71; p < 0.001), particularly in those who remained on study medication three days after AE onset (10 vs. 43; p < 0.001). There were fewer deaths attributed to sepsis in the ticagrelor group (7 vs. 23; p = 0.003). Leukocyte counts were lower in the clopidogrel group during treatment (p < 0.0001 at 1, 3 and 6 months) but not at 1 month post-discontinuation. C-reactive protein increased more at discharge in the ticagrelor group (28.0 ± 38.0 vs. 26.1 ± 36.6 mg/l; p < 0.001) and interleukin-6 remained higher during the first month of treatment with ticagrelor. We conclude that the mortality risk following pulmonary AEs and sepsis in acute coronary syndrome patients appears to be lower during ticagrelor compared to clopidogrel therapy. Further work should assess whether ticagrelor and clopidogrel have differential effects on immune signalling.

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.

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.

Outcome and causes of renal deterioration evaluated by serial cystatin C measurements in acute coronary syndrome patients—Results from the PLATelet inhibition and patient Outcomes (PLATO) study

BACKGROUND To investigate if ticagrelor treatment and other clinical characteristics were associated with increased cystatin C concentrations and if a deterioration in estimated renal function was associated with worse outcome in patients with acute coronary syndromes (ACS). METHODS Plasma cystatin C concentrations were determined within 24 hours of admission (baseline), at discharge, 1 month, and 6 months in the PLATO trial. The changes over time in relation to randomized treatment were analyzed by analysis of covariance. C-statistics and the relative Integrated Discrimination Improvement of the cystatin C concentrations regarding the primary outcome (cardiovascular death or myocardial infarction) was evaluated by multivariable analysis including background characteristics and biomarkers: N-terminal-pro-B-type natriuretic peptide and Troponin I. RESULTS Mean cystatin C concentrations in 2133 ticagrelor- and 2162 clopidogrel-treated patients were at baseline (0.86 mg/L and 0.86 mg/L), discharge (1.01 mg/L and 0.98 mg/L) (P < .0005), 1 month (1.00 mg/L and 0.98 mg/L) (P = .12), and 6 months (1.00 mg/L and 0.99 mg/L) (P = .17), respectively. Age, heart failure, and type of ACS were major determinants of the cystatin C concentration. c Statistics and the relative Integrated Discrimination Improvement of the primary outcome for the baseline cystatin C concentration were 0.687 and 5.2%, compared to 0.684 and 4.5% at discharge (n = 4034) and 0.693 and 5.1% at one month (n = 3096), respectively. CONCLUSIONS Mean cystatin C concentrations increased in ACS patients, most importantly determined by age. The initial greater increase in ticagrelor-treated patients was not sustained over time. Risk prediction did not improve with serial measurements of renal markers.