Steven V. Manoukian

Standard- vs high-dose clopidogrel based on platelet function testing after percutaneous coronary intervention: the GRAVITAS randomized trial.

CONTEXT High platelet reactivity while receiving clopidogrel has been linked to cardiovascular events after percutaneous coronary intervention (PCI), but a treatment strategy for this issue is not well defined. OBJECTIVE To evaluate the effect of high-dose compared with standard-dose clopidogrel in patients with high on-treatment platelet reactivity after PCI. DESIGN, SETTING, AND PATIENTS Randomized, double-blind, active-control trial (Gauging Responsiveness with A VerifyNow assay-Impact on Thrombosis And Safety [GRAVITAS]) of 2214 patients with high on-treatment reactivity 12 to 24 hours after PCI with drug-eluting stents at 83 centers in North America between July 2008 and April 2010. INTERVENTIONS High-dose clopidogrel (600-mg initial dose, 150 mg daily thereafter) or standard-dose clopidogrel (no additional loading dose, 75 mg daily) for 6 months. MAIN OUTCOME MEASURES The primary end point was the 6-month incidence of death from cardiovascular causes, nonfatal myocardial infarction, or stent thrombosis. The key safety end point was severe or moderate bleeding according to the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) definition. A key pharmacodynamic end point was the rate of persistently high on-treatment reactivity at 30 days. RESULTS At 6 months, the primary end point had occurred in 25 of 1109 patients (2.3%) receiving high-dose clopidogrel compared with 25 of 1105 patients (2.3%) receiving standard-dose clopidogrel (hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.58-1.76; P = .97). Severe or moderate bleeding was not increased with the high-dose regimen (15 [1.4%] vs 25 [2.3%], HR, 0.59; 95% CI, 0.31-1.11; P = .10). Compared with standard-dose clopidogrel, high-dose clopidogrel provided a 22% (95% CI, 18%-26%) absolute reduction in the rate of high on-treatment reactivity at 30 days (62%; 95% CI, 59%-65% vs 40%; 95% CI, 37%-43%; P < .001). CONCLUSIONS Among patients with high on-treatment reactivity after PCI with drug-eluting stents, the use of high-dose clopidogrel compared with standard-dose clopidogrel did not reduce the incidence of death from cardiovascular causes, nonfatal myocardial infarction, or stent thrombosis. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00645918.

Intravenous Platelet Blockade with Cangrelor during PCI

BACKGROUND Intravenous cangrelor, a rapid-acting, reversible adenosine diphosphate (ADP) receptor antagonist, might reduce ischemic events during percutaneous coronary intervention (PCI). METHODS In this double-blind, placebo-controlled study, we randomly assigned 5362 patients who had not been treated with clopidogrel to receive either cangrelor or placebo at the time of PCI, followed by 600 mg of clopidogrel. The primary end point was a composite of death, myocardial infarction, or ischemia-driven revascularization at 48 hours. Enrollment was stopped when an interim analysis concluded that the trial would be unlikely to show superiority for the primary end point. RESULTS The primary end point occurred in 185 of 2654 patients receiving cangrelor (7.0%) and in 210 of 2641 patients receiving placebo (8.0%) (odds ratio in the cangrelor group, 0.87; 95% confidence interval [CI], 0.71 to 1.07; P=0.17) (modified intention-to-treat population adjusted for missing data). In the cangrelor group, as compared with the placebo group, two prespecified secondary end points were significantly reduced at 48 hours: the rate of stent thrombosis, from 0.6% to 0.2% (odds ratio, 0.31; 95% CI, 0.11 to 0.85; P=0.02), and the rate of death from any cause, from 0.7% to 0.2% (odds ratio, 0.33; 95% CI, 0.13 to 0.83; P=0.02). There was no significant difference in the rate of blood transfusion (1.0% in the cangrelor group and 0.6% in the placebo group, P=0.13), though major bleeding on one scale was increased in the cangrelor group, from 3.5% to 5.5% (P<0.001), because of more groin hematomas. CONCLUSIONS The use of periprocedural cangrelor during PCI was not superior to placebo in reducing the primary end point. The prespecified secondary end points of stent thrombosis and death were lower in the cangrelor group, with no significant increase in the rate of transfusion. Further study of intravenous ADP blockade with cangrelor may be warranted. (ClinicalTrials.gov number, NCT00385138.)

A Risk Score to Predict Bleeding in Patients With Acute Coronary Syndromes

OBJECTIVES The aim of this study was to develop a practical risk score to predict the risk and implications of major bleeding in acute coronary syndromes (ACS). BACKGROUND Hemorrhagic complications have been strongly linked with subsequent mortality in patients with ACS. METHODS A total of 17,421 patients with ACS (including non-ST-segment elevation myocardial infarction [MI], ST-segment elevation MI, and biomarker negative ACS) were studied in the ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) and the HORIZONS-AMI (Harmonizing Outcomes with RevasculariZatiON and Stents in Acute Myocardial Infarction) trials. An integer risk score for major bleeding within 30 days was developed from a multivariable logistic regression model. RESULTS Non-coronary artery bypass graft surgery (CABG)-related major bleeding within 30 days occurred in 744 patients (7.3%) and had 6 independent baseline predictors (female sex, advanced age, elevated serum creatinine and white blood cell count, anemia, non-ST-segment elevation MI, or ST-segment elevation MI) and 1 treatment-related variable (use of heparin + a glycoprotein IIb/IIIa inhibitor rather than bivalirudin alone) (model c-statistic = 0.74). The integer risk score differentiated patients with a 30-day rate of non-CABG-related major bleeding ranging from 1% to over 40%. In a time-updated covariate-adjusted Cox proportional hazards regression model, major bleeding was an independent predictor of a 3.2-fold increase in mortality. The link to mortality risk was strongest for non-CABG-related Thrombolysis In Myocardial Infarction (TIMI)-defined major bleeding followed by non-TIMI major bleeding with or without blood transfusions, whereas isolated large hematomas and CABG-related bleeding were not significantly associated with subsequent mortality. CONCLUSIONS Patients with ACS have marked variation in their risk of major bleeding. A simple risk score based on 6 baseline measures plus anticoagulation regimen identifies patients at increased risk for non-CABG-related bleeding and subsequent 1-year mortality, for whom appropriate treatment strategies can be implemented.

Hypertension and left ventricular hypertrophy are associated with impaired endothelium-mediated relaxation in human coronary resistance vessels.

BackgroundPatients with hypertension and myocardial hypertrophy may have signs and symptoms of myocardial ischemia in the absence of obstructive coronary disease. Prior investigations have demonstrated impaired coronary flow reserve and have led to speculation that microvascular dysfunction might contribute to ischemia in these patients. Experimental studies have shown that the endothelium, an important regulator of microvascular tone, can be damaged by hypertension and is dysfunctional in cardiomyopathy. We hypothesized that endothelium-dependent vasodilation is impaired in the coronary microvasculature of patients with hypertension and ventricular hypertrophy. Methods and ResultsWe studied coronary microvascular responses in 10 patients with left ventricular hypertrophy secondary to essential hypertension (HTN) (mean arterial pressure at catheterization, 151/94 mm Hg; mean posterior wall thickness, 1.4±0.1 cm) and nine normal control subjects with no history of hypertension (mean arterial pressure at catheterization, 128/75 mm Hg; mean posterior wall thickness, 1.0±0.02 cm) using the intracoronary Doppler catheter and quantitative angiography to assess changes in coronary blood flow (CBF). All patients had normal left ventricular systolic function. To assess microvascular endothelial function, we infused the endothelium-dependent vasodilator acetylcholine (10−8–−6 M) and the endothelium-independent vasodilator adenosine (10−6–10−4 M) into the left anterior descending coronary artery. In response to acetylcholine, CBF increased only 32±25% in HTN patients, whereas CBF increased 192±39% in normal control subjects (p=0.003). CBF increased 465±93% in HTN patients and 439±41% in normal control subjects in response to adenosine (p=NS). The proportion of coronary flow reserve attributable to endothelium-dependent dilation (obtained from peak acetylcholine/peak adenosine flow response) was 48±9% in normal control subjects but only 7±8% in HTN patients (p=0.008). ConclusionsEndothelium-dependent vasodilation is markedly impaired in the coronary microvessels of patients with hypertension and ventricular hypertrophy. Loss of this vasodilator mechanism may contribute to disordered coronary flow regulation and the ischemic manifestations of hypertensive heart disease.

Bivalirudin in patients with acute coronary syndromes undergoing percutaneous coronary intervention: a subgroup analysis from the Acute Catheterization and Urgent Intervention Triage strategy (ACUITY) trial

BACKGROUND The aim of this study was to assess anticoagulation with the direct thrombin inhibitor bivalirudin during percutaneous coronary intervention in individuals with moderate and high-risk acute coronary syndromes. METHODS 13,819 individuals in the Acute Catheterization and Urgent Intervention Triage strategy (ACUITY) trial were prospectively randomly assigned to receive heparin (unfractionated or enoxaparin) plus glycoprotein IIb/IIIa inhibitors, bivalirudin plus glycoprotein IIb/IIIa inhibitors, or bivalirudin alone. Of these individuals, 7789 underwent percutaneous coronary intervention after angiography. The effect of the three regimens on the primary 30-day endpoints of composite ischaemia (death, myocardial infarction, or unplanned revascularisation for ischaemia), major bleeding, and net clinical outcomes (composite ischaemia or major bleeding) was assessed in this subgroup. Analyses were done by intention to treat. This trial is registered with ClinicalTrials.gov, with the number NCT00093158. FINDINGS Of the individuals who underwent percutaneous coronary intervention, 2561 received heparin plus glycoprotein IIb/IIIa inhibitors, 2609 received bivalirudin plus glycoprotein IIb/IIIa inhibitors, and 2619 received bivalirudin alone. 26 (0.3%) individuals dropped out or were lost to follow-up. There was no significant difference in the proportion of individuals with composite ischaemia, major bleeding, or net clinical outcomes at 30 days between those who received bivalirudin plus glycoprotein IIb/IIIa inhibitors and those who received heparin plus glycoprotein IIb/IIIa inhibitors (composite ischaemia: 243 [9%] patients vs 210 [8%] patients, p=0.16; major bleeding: 196 [8%] patients vs 174 [7%] patients, p=0.32; net clinical outcomes: 389 [15%] patients vs 341 [13%] patients, p=0.1). Rates of composite ischaemia were much the same in those who received bivalirudin alone and those who received heparin plus glycoprotein IIb/IIIa inhibitors (230 [9%] patients vs 210 [8%] patients, p=0.45); however, there were significantly fewer individuals who experienced major bleeding among those who received bivalirudin alone than among those who received heparin plus glycoprotein IIb/IIIa inhibitors (92 [4%] patients vs 174 [7%] patients, p<0.0001, relative risk 0.52, 95% CI 0.40-0.66), resulting in a trend towards better 30-day net clinical outcomes (303 [12%] patients vs 341 [13%] patients, p=0.057; 0.87, 0.75-1.00). INTERPRETATION Substitution of unfractionated heparin or enoxaparin with bivalirudin results in comparable clinical outcomes in patients with moderate and high-risk acute coronary syndromes treated with glycoprotein IIb/IIIa inhibitors in whom percutaneous coronary intervention is done. Anticoagulation with bivalirudin alone suppresses adverse ischaemic events to a similar extent as does heparin plus glycoprotein IIb/IIIa inhibitors, while significantly lowering the risk of major haemorrhagic complications.

Platelet Reactivity and Cardiovascular Outcomes After Percutaneous Coronary Intervention A Time-Dependent Analysis of the Gauging Responsiveness With a VerifyNow P2Y12 Assay: Impact on Thrombosis and Safety (GRAVITAS) Trial

Background— In the Gauging Responsiveness With A VerifyNow P2Y12 Assay: Impact on Thrombosis and Safety (GRAVITAS) trial, 6 months of high-dose clopidogrel did not reduce cardiovascular events compared with standard-dose clopidogrel in patients with high on-treatment platelet reactivity (OTR) after percutaneous coronary intervention, defined as OTR ≥230 P2Y12 reaction units according to the VerifyNow P2Y12 platelet function test. The aim of this analysis was to examine the relationship between outcomes and OTR over the course of the trial. Methods and Results— OTR was measured at 12 to 24 hours and 30±7 days after percutaneous coronary intervention. Cox proportional hazards models with OTR as a time-varying covariate were used to determine the association between OTR and the primary end point of cardiovascular death, myocardial infarction, and stent thrombosis. Of the 2800 enrolled patients, 2796 (99.98%) had evaluable platelet function data. OTR <208 P2Y12 reaction units was significantly associated with a lower risk of the primary end point at 60 days (hazard ratio, 0.18; 95% confidence interval, 0.04 to 0.79; P=0.02) and at 6 months (hazard ratio, 0.43; 95% confidence interval, 0.23 to 0.82; P=0.01). After adjustment for other significant predictors of outcome, OTR <208 P2Y12 reaction units remained independently associated with the primary end point at 60 days (hazard ratio, 0.23; 95% confidence interval, 0.05 to 0.98; P=0.047) and tended to be associated at 6 months (adjusted hazard ratio, 0.54; 95% confidence interval, 0.28 to 1.04; P=0.065). Conclusions— In the GRAVITAS trial, achievement of on-clopidogrel reactivity <208 P2Y12 reaction units at 12 to 24 hours after percutaneous coronary intervention or during follow-up was associated with a lower risk for cardiovascular events. The efficacy of an individualized strategy to target a level of OTR below this threshold merits investigation. Clinical Trial Registration— http://www.clinicaltrials.gov. Unique identifier: NCT00645918.

Associations of major bleeding and myocardial infarction with the incidence and timing of mortality in patients presenting with non-ST-elevation acute coronary syndromes: a risk model from the ACUITY trial

AIMS To evaluate the associations of myocardial infarction (MI) and major bleeding with 1-year mortality. Both MI and major bleeding predict 1-year mortality in patients presenting with acute coronary syndrome (ACS). However, the risk of each of these events on the magnitude and timing of mortality has not been well studied. METHODS AND RESULTS A multivariable Cox regression model was developed relating 13 independent baseline predictors to 1-year mortality for 13 819 patients with moderate and high-risk ACS enrolled in the Acute Catheterization and Urgent Intervention Triage strategy trial. After adjustment for baseline predictors, Cox models with major bleeding and recurrent MI as time-updated covariates estimated the effect of these events on mortality hazard over time. Within 30 days of randomization, 705 patients (5.1%) had an MI, 645 (4.7%) had a major bleed; 524 (3.8%) died within a year. The occurrence of an MI was associated with a hazard ratio of 3.1 compared with patients not yet having an MI, after adjustment for baseline predictors. However, MI within 30 days markedly increased the mortality risk for the first 2 days after the event (adjusted hazard ratio of 17.6), but this risk declined rapidly post-infarct (hazard ratio of 1.4 beyond 1 month after the MI event). In contrast, major bleeding had a prolonged association with mortality risk (hazard ratio of 3.5) which remained fairly steady over time throughout 1 year. CONCLUSION After accounting for baseline predictors of mortality, major bleeds and MI have similar overall strength of association with mortality in the first year after ACS. MI is correlated with a dramatic increase in short-term risk, whereas major bleeding correlates with a more prolonged mortality risk.

Impact of bleeding on mortality after percutaneous coronary intervention: Results from a patient-level pooled analysis of the REPLACE-2 (Randomized Evaluation of PCI Linking Angiomax to Reduced Clinical Events), ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy), and HORIZONS-AMI (Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction) trials

OBJECTIVES This study sought to develop a risk score predictive of bleeding in patients undergoing percutaneous coronary intervention (PCI) and to investigate the impact of bleeding on subsequent mortality. BACKGROUND Bleeding complications after PCI have been independently associated with early and late mortality. METHODS This study represents a patient-level pooled analysis including 17,034 patients undergoing PCI from 3 large, randomized trials of bivalirudin versus heparin plus glycoprotein IIb/IIIa inhibitors, including the REPLACE-2 (Randomized Evaluation of PCI Linking Angiomax to Reduced Clinical Events), ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy), and HORIZONS-AMI (Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction) trials. We developed a risk score to predict noncoronary artery bypass graft (CABG)-related TIMI (Thrombolysis In Myocardial Infarction) major bleeding and evaluated the impact of various types of bleeding on 1-year mortality. RESULTS A non-CABG-related TIMI major bleed occurred within 30 days in 267 patients (1.6%), and death occurred in 497 patients (2.9%) within 1 year. A risk score was developed to predict the bleeding risk of patients undergoing PCI, consisting of 7 variables (serum creatinine, age, sex, presentation, white blood cell count, cigarette smoking, and randomized treatment). The TIMI major bleeding rates increased by bleeding risk score groups: from 0.4% for those in the lowest to 5.8% for those in the highest risk group. Non-CABG-related TIMI major bleeding and the occurrence of myocardial infarction within 30 days were independent predictors of subsequent mortality, with respective hazard ratios of 4.2 and 2.9, each p < 0.001. Ranked in order of severity, TIMI major bleeding, blood transfusion without TIMI bleed, TIMI minor bleeding requiring blood transfusion, and TIMI minor bleeding not requiring blood transfusion were independent predictors of subsequent mortality with hazard ratios of 4.89, 2.91, 2.73, and 1.66, respectively. Isolated hematomas were not predictive of subsequent mortality. CONCLUSIONS Non-CABG-related bleeding within 30 days is strongly associated with an increased risk of subsequent mortality at 1 year in patients undergoing PCI for all indications. A risk score was established to calculate the bleeding risk for patients undergoing PCI, allowing therapeutic decision making to minimize the incidence of bleeding.

Integration of pre-hospital electrocardiograms and ST-elevation myocardial infarction receiving center (SRC) networks: impact on Door-to-Balloon times across 10 independent regions.

OBJECTIVES The aim of this study was to evaluate the rate of timely reperfusion for ST-elevation myocardial infarction (STEMI) with primary percutaneous coronary intervention (PPCI) in regional STEMI Receiving Center (SRC) networks. BACKGROUND The American College of Cardiology Door-to-Balloon (D2B) Alliance target is a >75% rate of D2B <or=90 min. Independent initiatives nationwide have organized regional SRC networks that coordinate universal access to 9-1-1 with the pre-hospital electrocardiogram (PH-ECG) diagnosis of STEMI and immediate transport to a SRC (designated PPCI-capable hospital). METHODS A pooled analysis of 10 independent, prospective, observational registries involving 72 hospitals was performed. Data were collected on all consecutive patients with a PH-ECG diagnosis of STEMI. The D2B and emergency medical services (EMS)-to-balloon (E2B) times were recorded. RESULTS Paramedics transported 2,712 patients with a PH-ECG diagnosis of STEMI directly to the nearest SRC. A PPCI was performed in 2,053 patients (76%) with an 86% rate of D2B <or=90 min (95% confidence interval: 84.4% to 87.4%). Secondary analyses of this cohort demonstrated a 50% rate of D2B <or=60 min (n = 1,031), 25% rate of D2B <or=45 min (n = 517), and an 8% rate of D2B <or=30 min (n = 155). A tertiary analysis restricted to 762 of 2,053 (37%) cases demonstrated a 68% rate of E2B <or=90 min. CONCLUSIONS Ten independent regional SRC networks demonstrated a combined 86% rate of D2B <or=90 min, and each region individually surpassed the American College of Cardiology D2B Alliance benchmark. In areas with regional SRC networks, 9-1-1 provides entire communities with timely access to quality STEMI care.

Outcomes Following Pre-Operative Clopidogrel Administration in Patients With Acute Coronary Syndromes Undergoing Coronary Artery Bypass Surgery The ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) Trial

OBJECTIVES This study sought to evaluate the impact of upstream clopidogrel in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) requiring coronary artery bypass grafting (CABG) from the ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) trial. BACKGROUND Despite benefits of clopidogrel in patients with NSTE-ACS undergoing percutaneous coronary intervention, this agent is often not administered upstream (before angiography) as recommended by the American College of Cardiology/American Heart Association guidelines because of potential bleeding in the minority of patients who require CABG. METHODS The ACUITY trial enrolled 13,819 patients with NSTE-ACS undergoing early invasive management. The timing of clopidogrel initiation was per investigator discretion. A 5-day washout period before CABG was recommended for patients having received clopidogrel. RESULTS Of 13,819 patients enrolled, 1,539 (11.1%) underwent CABG before discharge. Clopidogrel-exposed patients had a longer median duration of hospitalization (12.0 days vs. 8.9 days, p < 0.0001), but fewer adverse composite ischemic events (death, myocardial infarction, or unplanned revascularization) at 30 days; 12.7% vs. 17.3%, p = 0.01), with nonsignificantly different rates of non-CABG-related major bleeding (3.4% vs. 3.2%, p = 0.87) and post-CABG major bleeding (50.3% vs. 50.9%, p = 0.83) compared with those patients not administered clopidogrel. By multivariable analysis, clopidogrel use before CABG was an independent predictor of reduced 30-day composite ischemia (odds ratio: 0.67, 95% confidence interval: 0.48 to 0.92, p = 0.001) but not of increased post-CABG major bleeding (odds ratio: 0.98, 95% confidence interval: 0.80 to 1.19, p = 0.80). CONCLUSIONS Clopidogrel administration before catheterization in patients with NSTE-ACS requiring CABG is associated with significantly fewer 30-day adverse ischemic events without significantly increasing major bleeding, compared to withholding clopidogrel until after angiography. These findings support the American College of Cardiology/American Heart Association guidelines for upstream clopidogrel administration in all NSTE-ACS patients, including those who subsequently undergo CABG. (Comparison of Angiomax Versus Heparin in Acute Coronary Syndromes [ACS]; NCT00093158).