Laurent Bonello

Consensus and Future Directions on the Definition of High On-Treatment Platelet Reactivity to Adenosine Diphosphate

The addition of clopidogrel to aspirin treatment reduces ischemic events in a wide range of patients with cardiovascular disease. However, recurrent ischemic event occurrence during dual antiplatelet therapy, including stent thrombosis, remains a major concern. Platelet function measurements during clopidogrel treatment demonstrated a variable and overall modest level of P2Y(12) inhibition. High on-treatment platelet reactivity to adenosine diphosphate (ADP) was observed in selected patients. Multiple studies have now demonstrated a clear association between high on-treatment platelet reactivity to ADP measured by multiple methods and adverse clinical event occurrence. However, the routine measurement of platelet reactivity has not been widely implemented and recommended in the guidelines. Reasons for the latter include: 1) a lack of consensus on the optimal method to quantify high on-treatment platelet reactivity and the cutoff value associated with clinical risk; and 2) limited data to support that alteration of therapy based on platelet function measurements actually improves outcomes. This review provides a consensus opinion on the definition of high on-treatment platelet reactivity to ADP based on various methods reported in the literature and proposes how this measurement may be used in the future care of patients.

Adjusted Clopidogrel Loading Doses According to Vasodilator-Stimulated Phosphoprotein Phosphorylation Index Decrease Rate of Major Adverse Cardiovascular Events in Patients With Clopidogrel Resistance A Multicenter Randomized Prospective Study

OBJECTIVES This study evaluates the clinical impact of adjusting the loading dose of clopidogrel according to vasodilator-stimulated phosphoprotein (VASP) index in patients with clopidogrel resistance undergoing percutaneous coronary intervention (PCI). BACKGROUND Clopidogrel resistance plays a key role in ischemic recurrence after PCI. In vitro tests of clopidogrel resistance can accurately predict major adverse cardiac events after PCI. METHODS In this prospective, randomized, multicenter study, clopidogrel resistance was defined as a VASP index of more than 50% after a 600-mg loading dose. Patients with clopidogrel resistance undergoing coronary stenting were randomized to a control group or to the VASP-guided group, in which patients received additional bolus clopidogrel to decrease the VASP index below 50%. RESULTS A total of 162 patients were included. The control (n = 84) and VASP-guided groups (n = 78) had similar demographic, clinical, and biological characteristics. In the VASP-guided group, dose adjustment was efficient in 67 patients (86%) and VASP index was significantly decreased (from 69.3 +/- 10 to 37.6 +/- 13.8; p < 0.001). Eight major adverse cardiac events (5%) were recorded during the 1-month follow-up, with a significantly lower rate in the VASP-guided group compared with the control group (0% vs. 10%; p = 0.007). There was no difference in the rate of major and minor bleeding (5% vs. 4%; p = 1). CONCLUSIONS This is the first study to suggest that adjusting the clopidogrel loading dose according to platelet monitoring using the VASP index is safe and may significantly improve the clinical outcome after PCI in patients with clopidogrel resistance despite a first 600-mg loading dose.

Consensus and Update on the Definition of On-Treatment Platelet Reactivity to Adenosine Diphosphate Associated With Ischemia and Bleeding

Dual antiplatelet therapy with aspirin and a P2Y12 receptor blocker is a key strategy to reduce platelet reactivity and to prevent thrombotic events in patients treated with percutaneous coronary intervention. In an earlier consensus document, we proposed cutoff values for high on-treatment platelet reactivity to adenosine diphosphate (ADP) associated with post-percutaneous coronary intervention ischemic events for various platelet function tests (PFTs). Updated American and European practice guidelines have issued a Class IIb recommendation for PFT to facilitate the choice of P2Y12 receptor inhibitor in selected high-risk patients treated with percutaneous coronary intervention, although routine testing is not recommended (Class III). Accumulated data from large studies underscore the importance of high on-treatment platelet reactivity to ADP as a prognostic risk factor. Recent prospective randomized trials of PFT did not demonstrate clinical benefit, thus questioning whether treatment modification based on the results of current PFT platforms can actually influence outcomes. However, there are major limitations associated with these randomized trials. In addition, recent data suggest that low on-treatment platelet reactivity to ADP is associated with a higher risk of bleeding. Therefore, a therapeutic window concept has been proposed for P2Y12 inhibitor therapy. In this updated consensus document, we review the available evidence addressing the relation of platelet reactivity to thrombotic and bleeding events. In addition, we propose cutoff values for high and low on-treatment platelet reactivity to ADP that might be used in future investigations of personalized antiplatelet therapy.

Vasodilator-stimulated phosphoprotein phosphorylation analysis prior to percutaneous coronary intervention for exclusion of postprocedural major adverse cardiovascular events.

Summary.  Background: Despite dual antiplatelet therapy, the rate of major adverse cardiovascular events (MACE) after percutaneous coronary angioplasty remains high. Studies have shown interindividual variations in response to clopidogrel. Furthermore, there is an apparent link between clinical outcomes and clopidogrel resistance. Objectives: To investigate the value of platelet reactivity index (PRI), assessed by vasodilator‐stimulated phosphoprotein (VASP) phosphorylation analysis, for predicting MACE after percutaneous coronary intervention (PCI) with stent implantation.Methods: A prospective monocentric study was performed on 144 patients undergoing PCI. PR was evaluated by VASP phosphorylation analysis 24 h after they received a 300‐mg loading dose of clopidogrel. MACE were recorded during a 6‐month follow‐up. Patients were divided into quintiles according to PRI, as assessed by VASP analysis. The receiver operating characteristic (ROC) curve served to determine the optimal cut‐off value of VASP analysis to detect MACE.Results: Of the 144 patients, 34% had stable angina pectoris, 40% silent ischemia, and 26% low‐risk non‐ST‐segment elevation acute coronary syndrome. During the follow‐up, 21 MACE were observed. Patients in quintile 1 of VASP analysis had a significantly lower risk of MACE as compared with those among the four higher quintiles (0 vs. 21, P < 0.01). ROC curve analysis of VASP showed an optimal cut‐off value of 50% PR to exclude MACE. The negative predictive value of the test was 100%.Conclusions: VASP phosphorylation analysis can evaluate the individual response to clopidogrel loading dose prior to PCI and predict postprocedural MACE.

Tailored clopidogrel loading dose according to platelet reactivity monitoring to prevent acute and subacute stent thrombosis.

Stent thrombosis remains a significant pitfall of percutaneous coronary intervention (PCI). A recent trial observed that an adjusted loading dose (LD) of clopidogrel according to platelet monitoring decreases the rate of major adverse cardiovascular events after PCI. We investigated if such a strategy of a tailored clopidogrel LD according to platelet reactivity monitoring could decrease the rate of stent thrombosis. This multicenter prospective randomized study included 429 patients with a low clopidogrel response after a 600-mg LD undergoing PCI. Patients were randomized to a control group (n = 214) and to a vasodilator-stimulated phosphoprotein (VASP)-guided group (n = 215). In the VASP-guided group, patients received up to 3 additional 600-mg LDs of clopidogrel to obtain a VASP index <50% before PCI. The primary end point was the rate of stent thrombosis at 1 month. Secondary end points were rates of major adverse cardiovascular events and bleeding. Patients in the 2 groups had a high body mass index and were often diabetic (control vs VASP-guided group 28 +/- 5.1 vs 27.9 +/- 4.7 kg/m(2), p = 0.8, and 39% vs 33%, p = 0.2, respectively). PCI was performed in most patients for acute coronary syndrome in the 2 groups (52.3% vs 50.7%, p = 0.8). Despite a 2,400-mg LD of clopidogrel, 8% of patients in the VASP-guided group remained low responders. The rate of stent thrombosis was significantly lower in the VASP-guided group (0.5% vs 4.2%, p <0.01). The rate of major adverse cardiovascular events was also higher in the control group (8.9% vs 0.5%, p <0.001). There was no difference in the rate of bleeding (2.8% vs 3.7%, p = 0.8). In conclusion, a tailored clopidogrel LD according to platelet reactivity monitoring decreases the rate of early stent thrombosis after PCI without increasing bleeding.

High on-treatment platelet reactivity after prasugrel loading dose and cardiovascular events after percutaneous coronary intervention in acute coronary syndromes.

OBJECTIVES The aim of this study was to investigate the relationship between platelet reactivity (PR) after a loading dose (LD) of prasugrel and thrombotic events. BACKGROUND Post-treatment PR has been shown to be strongly associated with the occurrence of major adverse cardiac events (MACE) after percutaneous coronary intervention (PCI) in the clopidogrel era. Prasugrel is a new P2Y(12)-adenosine diphosphate receptor with a higher potency on PR. METHODS A prospective multicenter study included patients who underwent successful PCI for acute coronary syndromes and received prasugrel therapy. Vasodilator-stimulated phosphoprotein (VASP) index was measured after the prasugrel LD. High on-treatment PR was defined as a VASP index ≥50%. MACE included cardiovascular death, myocardial infarction, and definite stent thrombosis at 1 month. RESULTS Three hundred one patients were enrolled. The mean VASP index after 60 mg of prasugrel was 34.3 ± 23.1%. High on-treatment PR was observed in 76 patients (25.2%). Patients experiencing thrombotic events after PCI had significantly higher VASP indexes compared with those free of events (64.4 ± 14.4% vs. 33.4 ± 22.7%; range: 51% to 64% and 5% to 47.6%, respectively; p = 0.001). Kaplan-Meier analysis comparing good responders and patients with high on-treatment PR demonstrated a significantly higher rate of MACE in patients with suboptimal PR inhibition (log-rank p < 0.001). Receiver-operating characteristic curve analysis found a cutoff value of 53.5% of the VASP index to predict thrombotic events at 1 month (r = 0.86, p < 0.001). Patients with minor or major Thrombolysis In Myocardial Infarction unrelated to coronary artery bypass grafting bleeding and those without had similar VASP indexes (30 ± 17.8% vs. 34.3 ± 23%, p = 0.70). CONCLUSIONS Despite the use of prasugrel, a significant number of patients undergoing PCI in the setting of acute coronary syndromes do not achieve optimal PR inhibition. Such patients have a higher risk for MACE after PCI.

Expert position paper on the role of platelet function testing in patients undergoing percutaneous coronary intervention

Optimizing outcomes after percutaneous coronary intervention (PCI) requires balancing between the risks of thrombotic and bleeding events in individual patients.1–3 However, finding the optimal balance is not always straightforward since the risks of thrombotic and bleeding complications may differ extremely between individuals. In addition, the individual effects of anticoagulant and antiplatelet drugs are not uniform in patients.4 Recent European guidelines1,3 recommend the use of prasugrel or ticagrelor instead of clopidogrel in all PCI-treated acute coronary syndrome (ACS) patients without contraindication, acknowledging that laboratory assessment of P2Y12-receptor inhibition may be considered only in selected cases when clopidogrel is used.1 However, there is no guidance with respect to the appropriate methodology and the suggested interpretation of results. The Working Group on Thrombosis of the European Society of Cardiology aimed to review the available evidence and the clinical relevance of platelet function testing in order to reach a consensus regarding the methodology, evaluation, and clinical interpretation of platelet function in patients undergoing PCI. Regarding the choice between available P2Y12-inhibitors, the 2011 ESC guidelines on non-ST segment elevation acute coronary syndromes (NSTE-ACS)1 and the 2012 guidelines on ST-segment elevation myocardial infarction3 recommend prasugrel and ticagrelor for all ACS patients without contraindication, and clopidogrel is only recommended if these agents are not available. Despite the restrictive recommendations for clopidogrel, it still holds a class I indication in ACS due to the large differences in the availability of the new-generation P2Y12-inhibitors among European countries. According to the 2011 ACCF/AHA/SCAI guidelines for PCI,5 a P2Y12-inhibitor should be given for ACS patients without preferring novel P2Y12-inhibitors over clopidogrel. Similarly, the 2012 ACCF/AHA unstable angina/non-ST-segment elevation myocardial infarction guidelines6 and the 2013 ACCF/AHA ST-elevation myocardial infarction guidelines …

Clinical Events as a Function of Proton Pump Inhibitor Use, Clopidogrel Use, and Cytochrome P450 2C19 Genotype in a Large Nationwide Cohort of Acute Myocardial Infarction Results From the French Registry of Acute ST-Elevation and Non–ST-Elevation Myocardial Infarction (FAST-MI) Registry

Background— Clopidogrel requires metabolic activation by cytochrome P450 2C19 (CYP2C19). Proton pump inhibitors (PPIs) that inhibit CYP2C19 are commonly coadministered with clopidogrel to reduce the risk of gastrointestinal bleeding. This analysis compares treatment outcomes for patients in the French Registry of Acute ST-Elevation and Non–ST-Elevation Myocardial Infarction (FAST-MI) who did or did not receive clopidogrel and/or PPIs. Methods and Results— The FAST-MI registry included 3670 patients (2744 clopidogrel- and PPI-naive patients) presenting with definite MI. Patients were categorized according to use of clopidogrel and/or PPI within 48 hours after hospital admission. PPI use was not associated with an increased risk for any of the main in-hospital events (in-hospital survival, reinfarction, stroke, bleeding, and transfusion). Likewise, PPI treatment was not an independent predictor of 1-year survival (hazard ratio, 0.97; 95% confidence interval [CI], 0.87 to 1.08; P =0.57) or 1-year MI, stroke, or death (hazard ratio, 0.98; 95% CI, 0.90 to 1.08; P =0.72). No differences were seen when the type of PPI or CYP2C19 genotype was taken into account. In the propensity-matched cohorts, the odds ratios for major in-hospital events in PPI versus no PPI were 0.29 (95% CI, 0.06 to 1.44) and 1.70 (95% CI, 0.10 to 30.3) for patients with 1 and 2 variant alleles, respectively. Similarly, the hazard ratio for 1-year events in hospital survivors was 0.68 (95% CI, 0.26 to 1.79) and 0.55 (95% CI, 0.06 to 5.30), respectively. Conclusion— PPI use was not associated with an increased risk of cardiovascular events or mortality in patients administered clopidogrel for recent MI, whatever the CYP2C19 genotype, although harm could not be formally excluded in patients with 2 loss-of-function alleles. Clinical Trial Registration— URL: . Unique identifier: [NCT00673036][1]. # Clinical Perspective {#article-title-33} [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00673036&atom=%2Fcirculationaha%2F123%2F5%2F474.atomBackground— Clopidogrel requires metabolic activation by cytochrome P450 2C19 (CYP2C19). Proton pump inhibitors (PPIs) that inhibit CYP2C19 are commonly coadministered with clopidogrel to reduce the risk of gastrointestinal bleeding. This analysis compares treatment outcomes for patients in the French Registry of Acute ST-Elevation and Non-ST-Elevation Myocardial Infarction (FAST-MI) who did or did not receive clopidogrel and/or PPIs. Methods and Results— The FAST-MI registry included 3670 patients (2744 clopidogrel- and PPI-naïve patients) presenting with definite MI. Patients were categorized according to use of clopidogrel and/or PPI within 48 hours after hospital admission. PPI use was not associated with an increased risk for any of the main in-hospital events (in-hospital survival, reinfarction, stroke, bleeding, and transfusion). Likewise, PPI treatment was not an independent predictor of 1-year survival (hazard ratio, 0.97; 95% confidence interval [CI], 0.87 to 1.08; P=0.57) or 1-year MI, stroke, or death (hazard ratio, 0.98; 95% CI, 0.90 to 1.08; P=0.72). No differences were seen when the type of PPI or CYP2C19 genotype was taken into account. In the propensity-matched cohorts, the odds ratios for major in-hospital events in PPI versus no PPI were 0.29 (95% CI, 0.06 to 1.44) and 1.70 (95% CI, 0.10 to 30.3) for patients with 1 and 2 variant alleles, respectively. Similarly, the hazard ratio for 1-year events in hospital survivors was 0.68 (95% CI, 0.26 to 1.79) and 0.55 (95% CI, 0.06 to 5.30), respectively. Conclusion— PPI use was not associated with an increased risk of cardiovascular events or mortality in patients administered clopidogrel for recent MI, whatever the CYP2C19 genotype, although harm could not be formally excluded in patients with 2 loss-of-function alleles. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00673036.

Bleeding and stent thrombosis on P2Y12-inhibitors: collaborative analysis on the role of platelet reactivity for risk stratification after percutaneous coronary intervention

AIMS Although platelet reactivity during P2Y12-inhibitors is associated with stent thrombosis (ST) and bleeding, standardized and clinically validated thresholds for accurate risk stratification after percutaneous coronary intervention (PCI) are lacking. We sought to determine the prognostic value of low platelet reactivity (LPR), optimal platelet reactivity (OPR), or high platelet reactivity (HPR) by applying uniform cut-off values for standardized devices. METHODS AND RESULTS Authors of studies published before January 2015, reporting associations between platelet reactivity, ST, and major bleeding were contacted for a collaborative analysis using consensus-defined, uniform cut-offs for standardized platelet function assays. Based on best available evidence for each device (exploratory studies), LPR-OPR-HPR categories were defined as <95, 95-208, and >208 PRU for VerifyNow, <19, 19-46, and >46 U for the Multiplate analyser and <16, 16-50, and >50% for VASP assay. Seventeen studies including 20 839 patients were used for the analysis; 97% were treated with clopidogrel and 3% with prasugrel. Patients with HPR had significantly higher risk for ST [risk ratio (RR) and 95% CI: 2.73 (2.03-3.69), P < 0.00001], yet a slight reduction in bleeding [RR: 0.84 (0.71-0.99), P = 0.04] compared with those with OPR. In contrast, patients with LPR had a higher risk for bleeding [RR: 1.74 (1.47-2.06), P < 0.00001], without any further benefit in ST [RR: 1.06 (0.68-1.65), P = 0.78] in contrast to OPR. Mortality was significantly higher in patients with HPR compared with other categories (P < 0.05). Validation cohorts (n = 14) confirmed all results of exploratory studies (n = 3). CONCLUSIONS Platelet reactivity assessment during thienopyridine-type P2Y12-inhibitors identifies PCI-treated patients at higher risk for mortality and ST (HPR) or at an elevated risk for bleeding (LPR).

Clopidogrel Loading Dose Adjustment According to Platelet Reactivity Monitoring in Patients Carrying the 2C19*2Loss of Function Polymorphism

OBJECTIVES We aimed to investigate the biological impact of a tailored clopidogrel loading dose (LD) according to platelet reactivity monitoring in carriers of the cytochrome (CYP) 2C19*2 loss-of-function polymorphism undergoing percutaneous coronary intervention for an acute coronary syndromes. BACKGROUND CYP2C19*2 polymorphism is associated with reduced clopidogrel metabolism and a worse prognosis after percutaneous coronary intervention. METHOD A prospective multicenter study enrolling 411 patients with non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention was performed. Platelet reactivity was measured using the vasodilator-stimulated phosphoprotein (VASP) index, and a cutoff value of ≥ 50% was used to define high on-treatment platelet reactivity (HTPR). The genetic polymorphism of CYP2C19 was determined by allele-specific polymerase chain reaction. In patients carrying CYP2C19*2 and exhibiting HTPR after a first 600-mg LD of clopidogrel, dose adjustment was performed by using up to 3 additional 600 mg LDs to obtain a VASP index <50%. RESULTS One hundred thirty-four patients (35.3%) carried at least one 2C19*2 allele (11 homozygotes [2.7%] and 123 heterozygotes [32.6%]). The VASP index in these patients was significantly higher than in homozygotic patients for the wild-type alleles (61.7 ± 18.4% vs. 49.2 ± 24.2%; p < 0.001). Of the 134 carriers of the loss-of-function polymorphism, 103 were considered to have HTPR. After a second clopidogrel LD, the VASP index was significantly decreased in these patients (69.7 ± 10.1% vs. 50.6 ± 17.6%; p < 0.0001). Finally, dose adjustment according to platelet reactivity monitoring, enabled 88% of 2C19*2 carriers exhibiting HTPR to reach a VASP index <50%. CONCLUSIONS Increased and tailored clopidogrel loading dose according to platelet reactivity monitoring overcome HTPR in carriers of the loss-of-function CYP2C19*2 polymorphism.