Diego Della Riva

Stent thrombosis with drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis

BACKGROUND The relative safety of drug-eluting stents and bare-metal stents, especially with respect to stent thrombosis, continues to be debated. In view of the overall low frequency of stent thrombosis, large sample sizes are needed to accurately estimate treatment differences between stents. We compared the risk of thrombosis between bare-metal and drug-eluting stents. METHODS For this network meta-analysis, randomised controlled trials comparing different drug-eluting stents or drug-eluting with bare-metal stents currently approved in the USA were identified through Medline, Embase, Cochrane databases, and proceedings of international meetings. Information about study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes was extracted. FINDINGS 49 trials including 50,844 patients randomly assigned to treatment groups were analysed. 1-year definite stent thrombosis was significantly lower with cobalt-chromium everolimus eluting stents (CoCr-EES) than with bare-metal stents (odds ratio [OR] 0·23, 95% CI 0·13-0·41). The significant difference in stent thrombosis between CoCr-EES and bare-metal stents was evident as early as 30 days (OR 0·21, 95% CI 0·11-0·42) and was also significant between 31 days and 1 year (OR 0·27, 95% CI 0·08-0·74). CoCr-EES were also associated with significantly lower rates of 1-year definite stent thrombosis compared with paclitaxel-eluting stents (OR 0·28, 95% CI 0·16-0·48), permanent polymer-based sirolimus-eluting stents (OR 0·41, 95% CI 0·24-0·70), phosphorylcholine-based zotarolimus-eluting stents (OR 0·21, 95% CI 0·10-0·44), and Resolute zotarolimus-eluting stents (OR 0·14, 95% CI 0·03-0·47). At 2-year follow-up, CoCr-EES were still associated with significantly lower rates of definite stent thrombosis than were bare-metal (OR 0·35, 95% CI 0·17-0·69) and paclitaxel-eluting stents (OR 0·34, 95% CI 0·19-0·62). No other drug-eluting stent had lower definite thrombosis rates compared with bare-metal stents at 2-year follow-up. INTERPRETATION In randomised studies completed to date, CoCr-EES has the lowest rate of stent thrombosis within 2 years of implantation. The finding that CoCr-EES also reduced stent thrombosis compared with bare-metal stents, if confirmed in future randomised trials, represents a paradigm shift. FUNDING The Cardiovascular Research Foundation.

Mortality in patients treated with extended duration dual antiplatelet therapy after drug-eluting stent implantation: a pairwise and Bayesian network meta-analysis of randomised trials

BACKGROUND Despite recent studies, the optimum duration of dual antiplatelet therapy (DAPT) after coronary drug-eluting stent placement remains uncertain. We performed a meta-analysis with several analytical approaches to investigate mortality and other clinical outcomes with different DAPT strategies. METHODS We searched Medline, Embase, Cochrane databases, and proceedings of international meetings on Nov 20, 2014, for randomised controlled trials comparing different DAPT durations after drug-eluting stent implantation. We extracted study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes. DAPT duration was categorised in each study as shorter versus longer, and as 6 months or shorter versus 1 year versus longer than 1 year. Analyses were done by both frequentist and Bayesian approaches. FINDINGS We identified ten trials published between Dec 16, 2011, and Nov 16, 2014, including 31,666 randomly assigned patients. By frequentist pairwise meta-analysis, shorter DAPT was associated with significantly lower all-cause mortality compared with longer DAPT (HR 0·82, 95% CI 0·69-0·98; p=0·02; number needed to treat [NNT]=325), with no significant heterogeneity apparent across trials. The reduced mortality with shorter compared with longer DAPT was attributable to lower non-cardiac mortality (0·67, 0·51-0·89; p=0·006; NNT=347), with similar cardiac mortality (0·93, 0·73-1·17; p=0.52). Shorter DAPT was also associated with a lower risk of major bleeding, but a higher risk of myocardial infarction and stent thrombosis. We noted similar results in a Bayesian framework with non-informative priors. By network meta-analysis, patients treated with 6-month or shorter DAPT and 1-year DAPT had higher risk of myocardial infarction and stent thrombosis but lower risk of mortality compared with patients treated with DAPT for longer than 1 year. Patients treated with DAPT for 6 months or shorter had similar rates of mortality, myocardial infarction, and stent thrombosis, but lower rates of major bleeding than did patients treated with 1-year DAPT. INTERPRETATION Although treatment with DAPT beyond 1 year after drug-eluting stent implantation reduces myocardial infarction and stent thrombosis, it is associated with increased mortality because of an increased risk of non-cardiovascular mortality not offset by a reduction in cardiac mortality. FUNDING None.

Clinical Outcomes With Drug-Eluting and Bare-Metal Stents in Patients With ST-Segment Elevation Myocardial Infarction Evidence From a Comprehensive Network Meta-Analysis

OBJECTIVES The authors investigated the relative safety and efficacy of different drug-eluting stents (DES) and bare metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) using a network meta-analysis. BACKGROUND The relative safety of DES and BMS in patients with STEMI continues to be debated, and whether advances have been made in this regard with second-generation DES is unknown. METHODS Randomized controlled trials comparing currently U.S. approved DES or DES with BMS in patients with STEMI were searched using MEDLINE, EMBASE, and Cochrane databases. Information on study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes was extracted. RESULTS Twenty-two trials including 12,453 randomized patients were analyzed. At 1-year follow-up, cobalt-chromium everolimus eluting stents (CoCr-EES) were associated with significantly lower rates of cardiac death or myocardial infarction (MI) and stent thrombosis (ST) than BMS. Differences in ST were apparent as early as 30 days and were maintained for 2 years. CoCr-EES were also associated with significantly lower rates of 1-year ST than paclitaxel-eluting stents (PES). Sirolimus-eluting stents (SES) were also associated with significantly lower rates of 1-year cardiac death/myocardial infarction than BMS. CoCr-EES, PES, and SES, but not zotarolimus-eluting stents, had significantly lower rates of 1-year target vessel revascularization (TVR) than BMS, with SES also showing lower rates of TVR than PES. CONCLUSIONS In patients with STEMI, steady improvements in outcomes have been realized with the evolution from BMS to first-generation and now second-generation DES, with the most favorable safety and efficacy profile thus far demonstrated with CoCr-EES.

Short- Versus Long-Term Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation: An Individual Patient Data Pairwise and Network Meta-Analysis

BACKGROUND Randomized controlled trials comparing short- (≤6 months) with long-term (≥1 year) dual antiplatelet therapy (DAPT) after drug-eluting stent(s) (DES) placement have been insufficiently powered to detect significant differences in the risk of major adverse cardiac events (MACE). OBJECTIVES This study sought to compare clinical outcomes between short- (≤6 months) and long-term (1 year) DAPT and among 3 months, 6 months, and 1 year of DAPT post-DES placement by performing an individual patient data pairwise and network meta-analysis. METHODS Randomized controlled trials comparing DAPT durations after DES placement were searched through the MEDLINE, EMBASE, and Cochrane databases and in international meeting proceedings. The primary study outcome was 1-year risk of MACE (cardiac death, myocardial infarction, or definite/probable stent thrombosis). RESULTS Four trials including 8,180 randomized patients were identified. At 1-year follow-up, short-term DAPT was associated with similar rates of MACE (hazard ratio [HR]: 1.11; 95% confidence interval [CI]: 0.86 to 1.43; p = 0.44), but significantly lower rates of bleeding (HR: 0.66; 95% CI: 0.46 to 0.94; p = 0.03) versus prolonged DAPT. Comparable results were apparent in the landmark period between DAPT discontinuation and 1-year follow-up (for MACE: HR: 1.20; 95% CI: 0.77 to 1.89; p = 0.42) (for bleeding: HR: 0.44; 95% CI: 0.21 to 0.91; p = 0.03). There were no significant differences in 1-year rates of MACE among 3-month versus 1-year DAPT, 6-month versus 1-year DAPT, or 3-month versus 6-month DAPT. CONCLUSIONS Compared with prolonged DAPT, short-term DAPT is associated with similar rates of MACE but lower rates of bleeding after DES placement.

Stent Thrombosis With Drug-Eluting Stents : Is the Paradigm Shifting?

First-generation drug-eluting stents (DES), which impart the controlled release of sirolimus or paclitaxel from durable polymers to the vessel wall, have been consistently shown to reduce the risk of restenosis and target vessel revascularization compared with bare metal stents (BMS). However, stent thrombosis (ST) emerged as a major safety concern with first-generation DES early after their adoption in clinical practice, requiring prolonged dual antiplatelet therapy. Pathological studies have shown that first-generation DES are associated with delayed arterial healing and polymer hypersensitivity reactions resulting in chronic inflammation, predisposing to late and very late ST. Second-generation DES have been developed to overcome these issues with improved stent designs and construction and the use of biocompatible and bioabsorbable polymers. Meta-analyses have shown that the thin-strut, fluoropolymer-coated cobalt-chromium everolimus-eluting stent (CoCr-EES) may be associated with lower rates of definite ST than other DES and, unexpectedly, even lower than BMS. The thin-strut structure of the stent platform, the thromboresistant properties of the fluoropolymer, and the reduced polymer and drug load may contribute to the low rate of ST with CoCr-EES. The notion of DES being safer than BMS represents a paradigm shift in the evolution of percutaneous coronary intervention. The relative safety and efficacy of fluoropolymer-coated CoCr-EES, DES with bioabsorbable polymers, and fully bioresorbable scaffolds are the subject of numerous ongoing large-scale trials.

Three, six, or twelve months of dual antiplatelet therapy after DES implantation in patients with or without acute coronary syndromes: an individual patient data pairwise and network meta-analysis of six randomized trials and 11 473 patients.

Aim We sought to determine whether the optimal dual antiplatelet therapy (DAPT) duration after drug-eluting stent (DES) placement varies according to clinical presentation. Methods and Results We performed an individual patient data pairwise and network meta-analysis comparing short-term (⩽6-months) versus long-term (1-year) DAPT as well as 3-month vs. 6-month vs 1-year DAPT. The primary study outcome was the 1-year composite risk of myocardial infarction (MI) or definite/probable stent thrombosis (ST). Six trials were included in which DAPT after DES consisted of aspirin and clopidogrel. Among 11 473 randomized patients 6714 (58.5%) had stable CAD and 4758 (41.5%) presented with acute coronary syndrome (ACS), the majority of whom (67.0%) had unstable angina. In ACS patients, ⩽6-month DAPT was associated with non-significantly higher 1-year rates of MI or ST compared with 1-year DAPT (Hazard Ratio (HR) 1.48, 95% Confidence interval (CI) 0.98–2.22; P = 0.059), whereas in stable patients rates of MI and ST were similar between the two DAPT strategies (HR 0.93, 95%CI 0.65–1.35; P = 0.71; Pinteraction = 0.09). By network meta-analysis, 3-month DAPT, but not 6-month DAPT, was associated with higher rates of MI or ST in ACS, whereas no significant differences were apparent in stable patients. Short DAPT was associated with lower rates of major bleeding compared with 1-year DAPT, irrespective of clinical presentation. All-cause mortality was not significantly different with short vs. long DAPT in both patients with stable CAD and ACS. Conclusions Optimal DAPT duration after DES differs according to clinical presentation. In the present meta-analysis, despite the fact that most enrolled ACS patients were relatively low risk, 3-month DAPT was associated with increased ischaemic risk, whereas 3-month DAPT appeared safe in stable CAD. Prolonged DAPT increases bleeding regardless of clinical presentation. Further study is required to identify the optimal duration of DAPT after DES in individual patients based on their relative ischaemic and bleeding risks.

Detection of Tissue Factor Antigen and Coagulation Activity in Coronary Artery Thrombi Isolated from Patients with ST-Segment Elevation Acute Myocardial Infarction

Introduction Although ruptured atherosclerotic plaques have been extensively analyzed, the composition of thrombi causing arterial occlusion in patients with ST-segment elevation acute myocardial infarction has been less thoroughly investigated. We sought to investigate whether coagulant active tissue factor can be retrieved in thrombi of patients with STEMI undergoing primary percutaneous coronary intervention. Methods Nineteen patients with ST-segment elevation acute myocardial infarction referred for primary percutaneous coronary intervention were enrolled in this study. Coronary thrombi aspirated from coronary arteries were routinely processed for paraffin embedding and histological evaluation (4 patients) or immediately snap frozen for evaluation of tissue factor activity using a modified aPTT test (15 patients). Immunoprecipitation followed by immunoblotting was also performed in 12 patients. Results Thrombi aspirated from coronary arteries showed large and irregular areas of tissue factor staining within platelet aggregates, and in close contact with inflammatory cells. Some platelet aggregates stained positive for tissue factor, whereas others did not. Monocytes consistently stained strongly for tissue factor, neutrophils had a more variable and irregular tissue factor staining, and red blood cells did not demonstrate staining for tissue factor. Median clotting time of plasma samples containing homogenized thrombi incubated with a monoclonal antibody that specifically inhibits tissue factor-mediated coagulation activity (mAb 5G9) were significantly longer than their respective controls (88.9 seconds versus 76.5 seconds, respectively; p<0.001). Tissue factor was also identified by immunoprecipitation in 10 patients, with significant variability among band intensities. Conclusions Active tissue factor is present in coronary artery thrombi of patients with ST-segment elevation acute myocardial infarction, suggesting that it contributes to activate the coagulation cascade ensuing in coronary thrombosis.

A new score for risk stratification of patients with acute coronary syndromes undergoing percutaneous coronary intervention: the ACUITY-PCI (Acute Catheterization and Urgent Intervention Triage Strategy-Percutaneous Coronary Intervention) risk score.

OBJECTIVES This study sought to develop a new score specific for patients with non-ST-segment elevation acute coronary syndromes (NSTEACS) undergoing percutaneous coronary intervention (PCI) (the ACUITY-PCI [Acute Catheterization and Urgent Intervention Triage Strategy-Percutaneous Coronary Intervention] risk score). BACKGROUND The TIMI (Thrombolysis In Myocardial Infarction) and GRACE (Global Registry for Acute Coronary Events) risk scores are recommended for risk stratification of patients with NSTEACS. However, these scores were not optimized for patients undergoing an early invasive strategy with PCI. METHODS The ACUITY-PCI risk score was created from data for 1,692 patients enrolled in the formal angiographic substudy of the ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy) trial by integrating clinical, angiographic, laboratory, and electrocardiographic variables selected by multivariable analysis. The score was subsequently validated in a different population of 846 patients and compared with the GRACE and TIMI risk scores, and the SYNTAX (Synergy Between PCI with Taxus and Cardiac Surgery) and Clinical SYNTAX scores. RESULTS Six variables (2 clinical, 1 laboratory/electrocardiographic, and 3 angiographic) were included in the ACUITY-PCI score: insulin-treated diabetes; renal insufficiency; baseline cardiac biomarker elevation or ST-segment deviation; bifurcation lesion; small vessel/diffuse coronary artery disease; and the extent of coronary artery disease. Event rates increased significantly across tertiles of ACUITY-PCI score. Compared with the other scores, the ACUITY-PCI score had the best discrimination (C-statistic), calibration (Hosmer-Lemeshow statistic), and index of separation. Moreover, the net reclassification improvement varied from 9% to 38% and the integrated discrimination index from 1.9% to 2.7%. CONCLUSIONS The ACUITY-PCI risk score is a new tool integrating clinical, angiographic, and laboratory/electrocardiographic variables specifically developed for patients with NSTEACS undergoing PCI. This score displayed better prognostic accuracy in terms of discrimination and calibration than other currently available scores for risk stratification of patients with NSTEACS. (Comparison of Angiomax Versus Heparin in Acute Coronary Syndromes [ACS]; NCT00093158).

Percutaneous coronary intervention versus coronary artery bypass graft for stable angina: Meta-regression of randomized trials☆ , ☆☆

AIMS Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) perform similarly in terms of lowering mortality and myocardial infarction rates in patients with stable angina, except in subjects with high-risk lesions. PCI is burdened from higher rates of revascularization, but offers a reduction in stroke. To date, the impact of clinical variables on the risk-benefit assessment has not been established. METHODS AND RESULTS Using event rates as a dependent variable, meta-regression was performed to test whether an interaction existed between baseline clinical features (age, gender, diabetes mellitus, previous myocardial infarction and ejection fraction) and choice of revascularization, focusing on death, myocardial infarction, repeat revascularization and stroke. 20 randomized clinical trials (RCT) including 12,844 patients with stable angina were included. Compared to CABG, PCI significantly reduced the risk of stroke, both at 30 days (odds ratio [OR] 0.36 [95% confidence interval: 0.20-0.62]) and at follow up (median=12 months, OR=0.57 [0.41-0.80]). This reduction in stroke was significantly higher in females (B=-0.12, p=0.03). For repeat revascularization, PCI performed worse than CABG, both in the overall population and in patients with multivessel disease (OR=4.71 [3.17-7.01]) and (OR=7.18 [4.32-11.93]). Women (B=3.4, p=0.01) and those with diabetes mellitus (B=1.8, p=0.002) were at increased risk of subsequent revascularization after PCI. CONCLUSION PCI significantly reduces the risk of stroke compared to CABG particularly in female patients: however the risk of revascularization is increased with PCI, especially in women and in those with diabetes.

Leukocyte Count Is a Modulating Factor for the Mortality Benefit of Bivalirudin in ST-Segment–Elevation Acute Myocardial Infarction The HORIZONS-AMI Trial

Background—Although the reduction in mortality with bivalirudin compared with unfractionated heparin plus glycoprotein IIb/IIIa inhibitors in the Harmonizing Outcome with Revascularization and Stent in Acute Myocardial Infarction (HORIZONS-AMI) trial has been attributed to lower rates of major bleeding, alternative mechanisms have not been investigated in depth. We sought to investigate whether there might be an interaction between white blood cell (WBC) count and bivalirudin for the risk of mortality, and whether this interaction is independent of major bleeding. Methods and Results—Among the 3602 patients enrolled in the HORIZONS-AMI trial, WBC count was available in 3433 (95.3%) patients. Patients were stratified according to WBC tertiles. At 1-year follow-up, bivalirudin was associated with significantly lower rates of mortality and cardiac mortality compared with unfractionated heparin plus glycoprotein IIb/IIIa inhibitors in patients in the upper WBC tertile (all-cause death: 4.1% versus 9.3%, respectively; P=0.0004; cardiac death: 2.0% versus 6.9%; respectively; P<0.0001) but not in patients in the mid-WBC or lower WBC tertiles. The reduction of mortality with bivalirudin across WBC tertiles was independent of major bleeding, and a significant interaction was apparent for 1-year all-cause mortality and cardiac mortality between WBC and bivalirudin therapy. Similar findings were apparent at 3 years. Conclusions—In patients with ST-segment–elevation myocardial infarction, a significant interaction between bivalirudin therapy and admission WBC count was apparent for 1-year mortality. The reduction in mortality was independent of major bleeding, suggesting that other mechanisms may be implicated in the survival benefit observed with bivalirudin. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00433966.