A critical appraisal of platelet glycoprotein IIb/IIIa inhibition

AbstractDespite the success of abciximab in preventing ischemic events after percutaneous coronary interventions, attempts to develop intravenous, small-molecule glycoprotein IIb/IIIa antagonists and diversify the clinical indications for these agents have produced varied results. The 30-day ischemic event reduction in the percutaneous coronary intervention trials has ranged by over three-fold (16% to 56%) and is greater among the acute coronary syndrome trials. The phase III trials exploring the role of oral glycoprotein IIb/IIIa inhibition have been consistently disappointing, with evolving evidence of increased mortality. Mechanisms contributing to these heterogeneous results may include normal variation in platelet or receptor number, differences in receptor activity, interpatient variation in pharmacological dose-response and the possibility of prothrombotic or nonglycoprotein IIb/IIIa effects. Plausibility of “suboptimal” effect is suggested by several recent studies. Trials investigating the role of intravenous small-molecule IIb/IIIa antagonists highlight the importance of effective dosing. The increase in bleeding and mortality observed in the oral glycoprotein IIb/IIIa studies indicate the consequences of suboptimal dosing on safety on one hand, while raising the possibility of important prothrombotic, counterregulatory or other sudden cardiac events. This article will undertake a review of the relevant platelet biology, discuss the mechanisms that may contribute to suboptimal antiplatelet efficacy with these agents and examine insights from the clinical trials supporting these concepts

Mortality benefit of beta-blockade after successful elective percutaneous coronary intervention

AbstractObjectivesThe goal of this study was to evaluate the mortality benefit of beta-blockers after successful percutaneous coronary intervention (PCI).BackgroundBeta-blockers reduce mortality after myocardial infarction (MI), though limited data are available regarding their role after successful PCI.MethodsEach year from 1993 through 1999, the first 1,000 consecutive patients undergoing PCI were systematically followed up. Patients presenting with acute or recent MI, shock, or unsuccessful revascularization procedures were excluded from the analysis. Clinical, procedural, and follow-up data of beta-blocker-treated and non-beta-blocker-treated patients were compared. A multivariate survival analysis model using propensity analysis was used to adjust for heterogeneity between the two groups.ResultsOf the 4,553 patients, 2,056 (45%) were treated with beta-blockers at the time of the procedure. Beta-blocker therapy was associated with a mortality reduction from 1.3% to 0.8% at 30 days (p = 0.13) and a reduction from 6.0% to 3.9% at one year (p = 0.0014). This survival benefit of beta-blockers was independent of left ventricular function, diabetic status, history of hypertension, or history of MI. Using propensity analysis, beta-blocker therapy remained an independent predictor for one-year survival after PCI (hazard ratio, 0.63; 95% confidence interval, 0.46 to 0.87; p = 0.0054).ConclusionsWithin this large prospective registry, beta-blocker use was associated with a marked long-term survival benefit among patients undergoing successful elective percutaneous coronary revascularization

The duration of pretreatment with ticlopidine prior to stenting is associated with the risk of procedure-related non–Q-wave myocardial infarctions

AbstractObjectives. This study sought to determine whether the duration of pretreatment with the adenosine diphosphate receptor antagonist ticlopidine prior to intracoronary stenting is associated with the incidence of procedure-related non–Q-wave myocardial infarctions (MIs).Background. Dual antiplatelet therapy with ticlopidine and aspirin is routinely used with stenting, although ticlopidine is commonly not begun until the day of the procedure. Periprocedural MIs are at least partially platelet-dependent events. As the maximal platelet inhibitory effects of this drug take 2 to 3 days to be realized, we hypothesized that longer treatment prior to stenting would be associated with lower rates of procedure-related MIs.Methods. We reviewed outcomes in 175 consecutive patients treated with ticlopidine prior to stenting at the Cleveland Clinic Foundation. Those patients with an elevation in creatine kinase above our laboratory normal (>210 IU/L) with ≥4% MB fraction on routine evaluation were defined as having a non–Q-wave MI.Results. There were 28 patients (16%) who had a non–Q-wave MI. Longer duration of ticlopidine pretreatment was strongly associated with a lower incidence of procedure-related non–Q-wave MIs (duration of pretreatment <1 day, 29% had MI; 1 to 2 days, 14%; ≥3 days, 5%; chi-square for trend = 9.6; p = 0.002). Ticlopidine pretreatment of ≥3 days was associated with a significant reduction in the risk of non–Q-wave MI (unadjusted odds ratio 0.18, 95% confidence interval = 0.04 to 0.78, p = 0.01) compared with pretreatment of <3 days.Conclusions. Among patients undergoing intracoronary stenting, beginning ticlopidine therapy several days prior to the procedure is associated with a reduced risk of procedural non–Q-wave MIs

Reduction in Overall Occurrences of Ischemic Events with Vorapaxar: Results from TRACER

BACKGROUND: Clinical trials traditionally use time-to-first-event analysis embedded within the composite endpoint of cardiovascular death (CVD), myocardial infarction (MI), or stroke. However, many patients have \u3e1 event, and this approach may not reflect overall experience. We addressed this by analyzing all cardiovascular events in TRACER. METHODS AND RESULTS: TRACER randomized 12 944 patients with non-ST-segment elevation acute coronary syndromes to placebo or to protease-activated receptor 1 antagonist vorapaxar with a median follow-up of 502 days (interquartile range, 349 to 667). Analysis of vorapaxar\u27s effect on recurrent CVD, MI, or stroke was prespecified using the Wei, Lin, and Weissfeld approach. Vorapaxar did not reduce the first occurrence of the primary endpoint of CVD, MI, stroke, revascularization, or rehospitalization for recurrent ischemia, but reduced the secondary composite endpoint of CVD, MI, or stroke (14.7% vorapaxar vs. 16.4% placebo; hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.81 to 0.98; P=0.02; number needed to treat [NNT], 81). Recurrent secondary events occurred in 2.7% of patients. Vorapaxar reduced overall occurrences of ischemic events, first and subsequent (HR, 0.88; 95% CI, 0.80 to 0.98; P=0.02; NNT, 51). Also, there was a trend indicating that vorapaxar reduced the expanded endpoint, including revascularization and rehospitalization for recurrent ischemia (HR, 0.92; 95% CI, 0.84 to 1.01; P=0.09). Vorapaxar increased overall occurrences of moderate and severe Global Use of Strategies to Open Occluded Coronary Arteries bleeding (HR, 1.42; 95% CI, 1.21 to 1.66; PP\u3c0.001). CONCLUSIONS: Vorapaxar reduced overall occurrences of ischemic events, but increased bleeding. These exploratory findings broaden our understanding of vorapaxar\u27s potential and expand our understanding of the value of capturing recurrent events

International variation in invasive care of the elderly with acute coronary syndromes

Aims To explore variations in invasive care of the elderly with acute coronary syndromes across international practice. Methods and results Using combined populations from the SYMPHONY and 2nd SYMPHONY trials, we describe 30-day cardiac catheterization in elderly (≥75 years; n=1794) vs. younger patients (<75 years; n=14 043) after multivariable adjustment and by region of enrolment. The use of cardiac catheterization and revascularization were not protocol-specified. Elderly patients (median age 78 years) were more often female and more frequently had hypertension, diabetes, prior myocardial infarction, and prior coronary bypass surgery. Overall, they underwent less cardiac catheterization than younger patients [53 vs. 63%; adjusted OR 0.53 (0.46, 0.60)]. The absolute rate of cardiac catheterization in the elderly varied from 77% (vs. 91% in younger patients) in the US cohort to 27% (vs. 41% in younger patients) in the non-US cohort. Revascularization of elderly who underwent cardiac catheterization was also higher in US than non-US cohorts (71.3 vs. 53.6%). There was a significant interaction between the patient age and the use of catheterization across US and non-US regions of enrolment, as well as differences in the predictors of catheterization in the elderly. Despite these findings, after adjustment, 90-day rates of death and death or myocardial infarction (MI) were not significantly different in elderly who underwent catheterization compared with those who did not. Conclusion Although older age is universally predictive of lower use of cardiac catheterization, marked variation in catheterization of the elderly exists across international practice. Demonstrated differences in patterns of use suggest a lack of consensus regarding optimal use of an invasive strategy in the elderl

Incidence, Patterns, and Associations Between Dual-Antiplatelet Therapy Cessation and Risk for Adverse Events Among Patients With and Without Diabetes Mellitus Receiving Drug-Eluting Stents: Results From the PARIS Registry.

OBJECTIVES: The aim of this study was to examine the frequency and clinical impact of different cessation patterns of dual-antiplatelet therapy (DAPT) after percutaneous coronary intervention with drug-eluting stents among patients with and those without diabetes mellitus (DM). BACKGROUND: Early DAPT suspension after percutaneous coronary intervention increases the risk for major adverse cardiac events. However, temporal variability in risk and relation to DAPT cessation patterns among patients with DM remain unclear. METHODS: Using data from the PARIS (Patterns of Non-Adherence to Anti-Platelet Regimens in Stented Patients) registry, 1,430 patients with DM (34%) and 2,777 without DM (66%) treated with drug-eluting stents were identified. DAPT cessation modes were classified as temporary interruption (<14 days), disruption because of bleeding or poor compliance, and physician-recommended discontinuation. RESULTS: During 2-year follow-up, DM was associated with an increased risk for thrombotic events but a similar risk for bleeding. The cumulative incidence of DAPT cessation was significantly lower in patients with versus those without DM (50.1% vs. 55.4%; p < 0.01), driven largely by less frequent physician-guided discontinuation beyond 1 year. In contrast, 2-year rates of interruption and disruption were similar between groups. When DAPT was interrupted or discontinued under physician guidance, the risk for major adverse cardiac events was unchanged compared with patients with DM on uninterrupted DAPT. Conversely, when DAPT was disrupted, the risk for major adverse cardiac events increased compared with uninterrupted DAPT, regardless of diabetic status, with no evidence of statistical interaction. CONCLUSIONS: DAPT cessation patterns vary according to diabetic status, with less frequent physician-guided discontinuation among patients with DM. The presence of DM does not emerge as a modifier of cardiovascular risk after DAPT cessation

Dual-Antiplatelet Therapy Cessation and Cardiovascular Risk in Relation to Age: Analysis From the PARIS Registry.

OBJECTIVES: The aim of this study was to examine the association between dual-antiplatelet therapy (DAPT) cessation and cardiovascular risk after percutaneous coronary intervention in relation to age. BACKGROUND: Examination of outcomes by age after percutaneous coronary intervention is relevant given the aging population. METHODS: Two-year clinical outcomes, incidence, and effect of DAPT cessation on outcomes were compared by ages ≤55, 56 to 74, and ≥75 years from the PARIS (Patterns of Non-Adherence to Antiplatelet Regimens in Stented Patients) registry. DAPT cessation included physician-recommended discontinuation, interruption for surgery, and disruption (from noncompliance or bleeding). Clinical endpoints were major adverse cardiac events (MACE) (a composite of cardiac death, definite or probable stent thrombosis, spontaneous myocardial infarction, or clinically indicated target lesion revascularization), a secondary restrictive definition of MACE (MACE2) excluding target lesion revascularization, and bleeding. RESULTS: A total of 1,192 patients (24%) were ≤55 years, 2,869 (57%) were 56 to 74 years, and 957 (19%) were ≥75 years of age. Patients ≥75 years of age had higher DAPT cessation rates and increased risk for MACE2, death, cardiac death, and bleeding compared with younger patients. Discontinuation and interruption were not associated with increased cardiovascular risk across age groups, whereas disruption was associated with increased risk for MACE and MACE2 in younger patients but not in patients ≥75 years of age (p for trend <0.05). CONCLUSIONS: Nonadherence and outcomes vary by age, with patients ≥75 years having the highest DAPT cessation rates. We observed no association between outcomes and DAPT cessation in patients ≥75 years, whereas discontinuation was associated with lower MACE rates and disruption with increased MACE rates in patients <75 years