A Point-of-Care Platelet Function Assay and C-Reactive Protein for Prediction of Major Cardiovascular Events After Drug-Eluting Stent Implantation

Ethnic Differences in Thrombotic Profiles of Acute Coronary Syndrome Patients and Relationship to Cardiovascular Outcomes: A Comparison of East Asian and White subjects

BACKGROUND

East Asians (EAs), compared to white Caucasians (W), have a lower risk of ischemic heart disease and a higher risk of bleeding with antithrombotic medications. The underlying mechanisms are incompletely understood.

OBJECTIVES

We sought to compare thrombotic profiles of EA and W patients with myocardial infarction (MI) and relate these to cardiovascular outcomes.

METHODS

In a prospective study in the United Kingdom and Korea, blood samples from patients (n = 515) with ST- or non-ST-elevation MI (STEMI and NSTEMI) were assessed using the Global Thrombosis Test, measuring thrombotic occlusion (OT) and endogenous fibrinolysis (lysis time [LT]). Patients were followed for 1 year for major adverse cardiovascular events (MACE) and bleeding.

RESULTS

EA patients showed reduced OT (longer OT) compared to W (646 seconds [470-818] vs. 436 seconds [320-580], p < 0.001), with similar LT. In STEMI, OT (588 seconds [440-759] vs. 361 seconds [274-462], p < 0.001) and LT (1,854 seconds [1,389-2,729] vs. 1,338 seconds [1,104-1,788], p < 0.001) were longer in EA than W. In NSTEMI, OT was longer (OT: 734 seconds [541-866] vs. 580 seconds [474-712], p < 0.001) and LT shorter (1519 seconds [1,058-2,508] vs. 1,898 seconds [1,614-2,806], p = 0.004) in EA than W patients. MACE was more frequent in W than EA (6.3 vs. 1.9%, p = 0.014) and bleeding infrequent. While OT was unrelated, LT was a strong independent predictor of MACE event after adjustment for risk factors (hazard ratio: 3.70, 95% confidence interval: 1.43-9.57, p = 0.007), predominantly in W patients, and more so in STEMI than NSTEMI patients.

CONCLUSION

EA patients exhibit different global thrombotic profiles to W, associated with a lower rate of cardiovascular events.

Residual Inflammatory Risk and its Association With Events in East Asian Patients After Coronary Intervention

BACKGROUND

East Asian population has a low level of inflammation compared with Western population. The prognostic implication of residual inflammatory risk (RIR) remains uncertain in East Asians.

OBJECTIVES

This study sought to provide an analysis to estimate early-determined RIR and its association with clinical outcomes in East Asian patients with coronary artery disease (CAD).

METHODS

In an East Asian registry including patients with CAD undergoing percutaneous coronary intervention (PCI) (n = 4,562), RIR status was determined by measuring high-sensitivity C-reactive protein (hsCRP) serially at admission and at 1-month follow-up. Patients were stratified into 4 groups according to hsCRP criteria (≥2 mg/L): 1) persistent low RIR (low_{on admission}-low_1 month: 51.0%); 2) fortified RIR (low_{on admission}-high _1 month: 10.3%); 3) attenuated RIR (high_{on admission}-low_1 month: 20.5%); and 4) persistent high RIR (high_{on admission}-high_1 month: 18.3%). The risks of all-cause death, ischemic events, and major bleeding were evaluated.

RESULTS

In our cohort, median levels of hsCRP were significantly decreased over time (1.3 to 0.9 mg/L; P < 0.001). Compared with hsCRP on admission, hsCRP at 1 month showed the greater associations with all-cause death and ischemic event. During clinical follow-up, risks of clinical events were significantly different across the groups (log-rank test, P < 0.001). Compared with other RIR groups, persistent high RIR showed the higher risk for all-cause death (HR_adjusted, 1.92; 95% CI: 1.44 to 2.55; P < 0.001), ischemic events (HR_adjusted, 1.26; 95% CI: 1.02 to 1.56; P = 0.032), and major bleeding (HR_adjusted, 1.98; 95% CI: 1.30 to 2.99; P < 0.001), respectively.

CONCLUSIONS

Approximately one-fifth of East Asian patients with CAD have persistent high RIR, which shows the close association with occurrence of ischemic and bleeding events. (Gyeongsang National University Hospital Registry [GNUH]; NCT04650529).

Cardiovascular Biomarkers: Lessons of the Past and Prospects for the Future

Cardiovascular diseases (CVDs) are a major healthcare burden on the population worldwide. Early detection of this disease is important in prevention and treatment to minimise morbidity and mortality. Biomarkers are a critical tool to either diagnose, screen, or provide prognostic information for pathological conditions. This review discusses the historical cardiac biomarkers used to detect these conditions, discussing their application and their limitations. Identification of new biomarkers have since replaced these and are now in use in routine clinical practice, but still do not detect all disease. Future cardiac biomarkers are showing promise in early studies, but further studies are required to show their value in improving detection of CVD above the current biomarkers. Additionally, the analytical platforms that would allow them to be adopted in healthcare are yet to be established. There is also the need to identify whether these biomarkers can be used for diagnostic, prognostic, or screening purposes, which will impact their implementation in routine clinical practice.

Prognostic implication of systemic inflammatory state on antiplatelet effect in patients after percutaneous coronary intervention for ST-elevation myocardial infarction: A retrospective cohort study

Patients with ST-elevation myocardial infarction (STEMI) show an inflammatory response. The level of systemic inflammation is known to affect platelet aggregation function and antiplatelet therapy, which leads to different clinical prognosis. This study aims to evaluate the prognostic implication of systemic inflammatory state in patients with STEMI undergoing percutaneous coronary intervention.In this study, 203 patients with STEMI who underwent primary percutaneous coronary intervention were included. The patients were divided into 3 groups based on the inflammation levels assessed by tertiles of high-sensitivity C-reactive protein (hs-CRP) level on admission. Platelet aggregation evaluation was performed by residual platelet reactivity, which was assessed by the value of residual ADP-induced light transmittance aggregometry after clopidogrel maintenance dose therapy and in follow-up. Major adverse cardiac events (MACEs) were defined to include all-cause mortality, cardiovascular mortality, reinfarction, target vessel revascularization (TVR), cardiopulmonary resuscitation, advanced heart failure, ventricular fibrillation or ventricular tachycardia, and atrioventricular block.Levels of white blood cell was observed to be significantly higher at high tertile levels. Residual ADP-induced platelet aggregation was significantly higher at high tertile levels after clopidogrel maintenance dose therapy and in follow-up. Multivariate analysis identified that reperfusion time, alanine aminotransferase, platelet count, ADP-induced light transmittance aggregometry in follow-up and hs-CRP was independent predictors of MACEs. Platelet inhibition function of clopidogrel decreases progressively at different inflammation levels. The different levels of hs-CRP were demonstrated to be associated with MACEs at follow-up assessments.The presence of hs-CRP was not only significantly associated with platelet inhibition function, but was also a prognostic marker in STEMI.

Heart Failure and Diabetes Mellitus: Biomarkers in Risk Stratification and Prognostication

Heart failure (HF) and type 2 diabetes mellitus (T2DM) have a synergistic effect on cardiovascular (CV) morbidity and mortality in patients with established CV disease (CVD). The aim of this review is to summarize the knowledge regarding the discriminative abilities of conventional and novel biomarkers in T2DM patients with established HF or at higher risk of developing HF. While conventional biomarkers, such as natriuretic peptides and high-sensitivity troponins demonstrate high predictive ability in HF with reduced ejection fraction (HFrEF), this is not the case for HF with preserved ejection fraction (HFpEF). HFpEF is a heterogeneous disease with a high variability of CVD and conventional risk factors including T2DM, hypertension, renal disease, older age, and female sex; therefore, the extrapolation of predictive abilities of traditional biomarkers on this population is constrained. New biomarker-based approaches are disputed to be sufficient for improving risk stratification and the prediction of poor clinical outcomes in patients with HFpEF. Novel biomarkers of biomechanical stress, fibrosis, inflammation, oxidative stress, and collagen turn-over have shown potential benefits in determining prognosis in T2DM patients with HF regardless of natriuretic peptides, but their role in point-to-care and in routine practice requires elucidation in large clinical trials.

Ethnic Difference of Thrombogenicity in Patients with Cardiovascular Disease: a Pandora Box to Explain Prognostic Differences

Arterial and venous atherothrombotic events are finely regulated processes involving a complex interplay between vulnerable blood, vulnerable vessel, and blood stasis. Vulnerable blood ('thrombogenicity') comprises complex interactions between cellular components and plasma factors (inflammatory, procoagulant, anticoagulant, and fibrinolytic factors). The extent of thrombogenicity may determine the progression of atheroma and the clinical manifestation of atherothrombotic events, with the highest thrombogenicity in African Americans and lowest in East Asians. Inherent thrombogenicity may influence clinical efficacy and safety of specific antithrombotic treatments in high-risk patients, which may in part explain the observation that East Asian patients have reduced anti-ischemic benefits and elevated bleeding risk with antithrombotic therapy compared to Caucasian patients. In this review, we discuss available evidence regarding the racial differences in thrombogenicity and its impact on clinical outcomes among patients with atherosclerotic cardiovascular disease.

Viscoelastic properties of clot formation and their clinical impact in East Asian versus Caucasian patients with stable coronary artery disease: a COMPARE-RACE analysis

Compared with Caucasian patients, East Asian patients with coronary artery disease (CAD) have demonstrated better clinical outcomes. We sought to compare the viscoelastic properties of clot formation and their impact on clinical outcomes in East Asian vs. Caucasian patients. We analyzed age- and sex-matched East Asian and Caucasian patients with stable CAD (n = 249 each). Viscoelastic properties of clot formation were assessed with thromboelastography (TEG), and 3-year clinical outcomes were recorded. Major adverse cardiovascular events (MACE) were defined as a composite of cardiovascular death, myocardial infarction, or stroke. Compared with Caucasians, East Asians showed lower platelet-fibrin clot strength (PFCS) (maximum amplitude [MA]: 61.8 ± 7.9 vs. 65.4 ± 5.0 mm, p < 0.001). In a multivariate analysis, high PFCS (defined as MA ≥ 68 mm) was significantly associated with MACE occurrence (odds ratio 6.27, 95% CI 2.41 to 16.30, p < 0.001). East Asians vs. Caucasians had lower prevalence of high PFCS (odds ratio 0.50, 95% CI 0.27 to 0.93, p = 0.028). In conclusion, this is the first study to demonstrate different viscoelastic properties of clot between East Asian and Caucasian patients with stable CAD. The platelet-fibrin clot strength was significantly associated with MACE in these patients and was significantly lower in East Asians. Future studies are warranted to further explore the mechanistic explanation and clinical importance of these findings.

BARI 2D: A Reanalysis Focusing on Cardiovascular Events

OBJECTIVE

To reanalyze the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial using a new composite cardiovascular disease (CVD) outcome to determine how best to treat patients with type 2 diabetes mellitus and stable coronary artery disease.

PATIENTS AND METHODS

From January 1, 2001, to November 30, 2008, 2368 patients with type 2 diabetes mellitus and angiographically proven coronary artery disease were randomly assigned to insulin-sensitizing (IS) or insulin-providing (IP) therapy and simultaneously to coronary revascularization (REV) or no or delayed REV (intensive medical therapy [MED]), with all patients receiving intensive medical treatment. The outcome of this analysis was a composite of 8 CVD events.

RESULTS

Four-year Kaplan-Meier rates for the composite CVD outcome were 35.8% (95% CI, 33.1%-38.5%) with IS therapy and 41.6% (95% CI, 38.7%-44.5%) with IP therapy (P=.004). Much of this difference was associated with lower in-trial levels of fibrinogen, C-reactive protein, and hemoglobin A_1c with IS therapy. Four-year composite CVD rates were 32.7% (95% CI, 30.0%-35.4%) with REV and 44.7% (95% CI, 41.8%-47.6%) with MED (P<.001). A beneficial effect of IS vs IP therapy was present with REV (27.7%; 95% CI, 24.0%-31.4% vs 37.5%; 95% CI, 33.6%-41.4%; P<.001), but not with MED (43.6%; 95% CI, 39.5%-47.7% vs 45.7%; 95% CI, 41.6%-49.8%; P=.37) (homogeneity, P=.05). This interaction between IS therapy and REV was limited to participants preselected for coronary artery bypass grafting (CABG). The lowest composite CVD rates occurred in patients preselected for CABG and assigned to IS therapy and REV (17.3%; 95% CI, 11.8%-22.8%).

CONCLUSION

In the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial, the IS treatment strategy and the REV treatment strategy each reduces cardiovascular events. The combination of IS drugs and CABG results in the lowest risk of subsequent CVD events.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00006305.

Temporal Variability of Platelet Reactivity in Patients Treated with Clopidogrel or Ticagrelor

Background and Objectives

The degree of antiplatelet response to P2Y12 inhibitors has been associated with clinical outcomes. The aim of this study was to test the variability of platelet reactivity over time among patients treated with clopidogrel or ticagrelor.

Methods

A single-center cohort of acute coronary syndrome patients that underwent percutaneous coronary intervention (PCI) was analyzed. Platelet reactivity was measured at baseline, 48 hours after PCI, 1 month, and 6 months after clopidogrel (n=79) or ticagrelor (n=93) treatment. High on-treatment platelet reactivity (HPR) was defined as ≥47 U, assessed by multiple electrode platelet aggregometry.

Results

Platelet reactivity in the clopidogrel group increased over time, 38.2±21.7 U at 48 hours, 41.4±22.3 U at 1 month, and 44.7±25.5 U at 6 months (p=0.018, 48 hours to 6 months). However, platelet reactivity in the ticagrelor group was not significantly changed, 21.4±12.6 U at 48 hours, 20.0±12.2 U at 1 month, and 22.8±13.8 U at 6 months (p=0.392). A platelet reactivity change over time of more than 20U was found in 67.1% of the patients with clopidogrel group and 34.4% of ticagrelor group (p<0.001). Between 48 hours and 6 months, 43% of patients changed their responder status in the clopidogrel group, and 13% in the ticagrelor group (p<0.001).

Conclusions

Although ticagrelor treatment resulted in less temporal variability of platelet reactivity than clopidogrel treatment in terms of HPR, platelet reactivity varied over time in a significant proportion of patients.

C-reactive protein and prognosis after percutaneous coronary intervention and bypass graft surgery for left main coronary artery disease: Analysis from the EXCEL trial

BACKGROUND

The prognostic impact of high-sensitivity C-reactive protein (CRP) levels in patients with left main coronary artery disease (LMCAD) treated with percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) is unknown. We sought to determine the effect of elevated baseline CRP levels on the 3-year outcomes after LMCAD revascularization and to examine whether CRP influenced the relative outcomes of PCI versus CABG.

METHODS

In the EXCEL trial, patients with LMCAD and Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) scores ≤32 were randomized to PCI versus CABG. The primary composite outcome of death, myocardial infarction (MI), or stroke was analyzed according to baseline CRP levels.

RESULTS

Among 999 patients with available CRP levels, median CRP was 3.10 mg/L (interquartile range 1.12-6.40 mg/L). The rate of the primary composite end point of death, MI, or stroke at 3 years steadily increased with greater baseline CRP levels. The adjusted relationship between the 3-year composite rate of death, MI, or stroke and baseline CRP modeled as a continuous log-transformed variable demonstrated steadily increasing event rates with greater CRP levels (adjusted hazard ratio, 1.26, 95% CI 1.10-1.44, P = .0008). Similarly, patients with CRP ≥10 mg/L had a 3-fold higher risk of the 3-year primary end point compared to patients with lower CRP levels (adjusted hazard ratio 2.92, 95% CI 1.88-4.54, P < .0001). The association between an elevated CRP level and the adjusted 3-year risk of the primary composite end point did not differ according to revascularization strategy (P_interaction = .75).

CONCLUSIONS

In patients with LMCAD undergoing revascularization, elevated baseline CRP levels were strongly associated with subsequent death, MI, and stroke at 3 years, irrespective of the mode of revascularization. Further studies are warranted to determine whether anti-inflammatory therapies may improve the prognosis of high-risk patients with LMCAD following revascularization.

Predictive value of baseline C-reactive protein for periprocedural myocardial infraction of higher risk stratifications: A retrospective cohort clinical study

Objective:

It is controversial whether preprocedural elevated high sensitivity C-reactive protein (CRP) could increase the incidence of periprocedural myocardial infraction (PMI) of higher risk stratifications. The primary aim of this study was to evaluate whether preoperative elevated CRP level was related to the incidence of PMI in patients who underwent percutaneous coronary intervention (PCI).

Methods:

A total of 4.426 patients [66 y (59, 75); 72.3% males] with normal preprocedural cardiac enzymes were prospectively divided into two groups; the elevated CRP group was defined as CRP >3 mg/L, which was approximately 30.4% of the patients. The relationship between CRP and the incidence of PMI was established by multivariate logistic regression analysis, and multivariate linear regression analysis was used to assess the correlation between CRP and the severity of myocardial injury.

Results:

The incidence rates were similar between the two groups with periprocedural myocardial minor necrosis (34.23% versus 32.74%, p=0.607), but significantly differed based on the 2007 (defined as cardiac enzymes >3-fold elevations), 31.25% in high CRP group versus 26.25% in low group [odds ratio (OR) 1.19; p=0.046] and the 2012 universal PMI (defined as cardiac enzymes >5-fold elevations with at least one clinical evidence, such as chest pain, ECG changes or imaging diagnosis of heart ischemia), 19.79% versus 15.35% (OR 1.26, p=0.023); besides, the PMI ratios increased in line with the elevation of CRP (p=0.006 for the 2007 and p=0.011 for the 2012 universal PMI). However, no significant linear relationship was found between CRP and high sensitivity cardiac troponin I peak post-PCI.

Conclusion:

Elevated baseline CRP was an independent risk factor for the incidence of the 2007 and the 2012 universal PMI rather than minor necrosis. However, CRP may not correlate with the severity of minor myocardial necrosis in patients with PMI.

High-sensitive C-reactive protein and dual antiplatelet in intracranial arterial stenosis

Objective

To determine the relationship of high-sensitive C-reactive protein (hsCRP) and the efficacy and safety of dual antiplatelet therapy in patients with and without intracranial arterial stenosis (ICAS) in the Clopidogrel in High-Risk Patients with Acute Non-disabling Cerebrovascular Events (CHANCE) trial.

Methods

A subgroup of 807 patients with both magnetic resonance angiography images and hsCRP measurement was analyzed. Cox proportional hazards models were used to assess the interaction of hsCRP levels with the effects of dual and single antiplatelet therapy.

Results

A total of 358 (44.4%) patients had ICAS and 449 (55.6%) did not. The proportion of patients with elevated hsCRP levels was higher in the ICAS group than in the non-ICAS group (40.2% vs 30.1%, p = 0.003). There was significant interaction between hsCRP and the 2 antiplatelet therapy groups in their effects on recurrent stroke after adjustment for confounding factors in the patients with ICAS (p = 0.012), but not in those without (p = 0.256). Compared with aspirin alone, clopidogrel plus aspirin significantly reduced the risk of recurrent stroke only in the patients with ICAS and nonelevated hsCRP levels (adjusted hazard ratio 0.27; 95% confidence interval 0.11 to 0.69; p = 0.006). Similar results were observed for composite vascular events. No significant difference in bleeding was found.

Conclusions

Presence of both ICAS and nonelevated hsCRP levels may predict better response to dual antiplatelet therapy in reducing new stroke and composite vascular events in minor stroke or high-risk TIA patients. Further large-scale randomized and controlled clinical trials are needed to confirm this finding.

Platelet function testing in acute cardiac care – is there a role for prediction or prevention of stent thrombosis and bleeding?

The role of platelet function testing in acute coronary syndrome patients undergoing percutaneous coronary intervention remains controversial despite the fact that high platelet reactivity is an independent predictor of stent thrombosis and emerging evidence suggests also a link between low platelet reactivity and bleeding. In this expert opinion paper, the Study Group on Biomarkers in Cardiology of the Acute Cardiovascular Care Association and the Working Group on Thrombosis of the European Society of Cardiology aim to provide an overview of current evidence in this area and recommendations for practicing clinicians.

Blood Biomarkers in Minor Stroke and Transient Ischemic Attack

Minor stroke and transient ischemic attack (TIA) are common disorders with a high rate of subsequent disabling stroke, so the early recognition and management of minor stroke and TIA is of great importance. At the moment, the diagnosis of these disorders is based on neurologic deficits in a stroke-clinician's examination of the patient, supplemented by the results of acute brain imaging. However, high variability in TIA diagnosis has been reported between physicians, even trained vascular neurologists, and image-based diagnostic confirmation is not always readily available. Some patients still have ischemic events despite sustained standard secondary preventive therapy. Blood biomarkers are promising to aid in the diagnosis, risk stratification, and individual treatment of minor stroke and TIA. Some studies are being conducted in this field. This mini-review aims to highlight potential biomarkers for diagnosis and those helpful in predicting the risk of future stroke and the selection of treatment.

Role of pre-procedural C-reactive protein level in the prediction of major adverse cardiac events in patients undergoing percutaneous coronary intervention: a meta-analysisof longitudinal studies

Numerous studies have reported the relation between pre-procedural C-reactive protein (CRP) levels and the risk of major adverse cardiac events (MACEs) in patients undergoing percutaneous coronary intervention (PCI). However, the results across the studies were inconsistent. The aim of this study was to evaluate the predictive effect of pre-procedural CRP levels and the risk of MACEs in patients undergoing PCI. Longitudinal studies on the association between pre-procedural CRP levels and MACEs were identified by electronic and manual searches. Summary risk ratios (RRs) and 95 % confidence intervals (CI) were calculated employing an inverse variance random-effects model irrespective of between-study heterogeneity. Thirty-three studies involving 34,367 patients with 4119 MACEs were included in this study. High CRP level was associated with increased incidences of MACEs, all-cause death, myocardial infarction, coronary revascularization, and clinical restenosis, with pooled RRs of 1.97 (95 % CI, 1.65, 2.35), 2.88 (95 % CI, 2.15, 3.86), 1.81 (95 % CI, 1.48, 2.21), 1.31 (95 % CI, 1.11, 1.56), and 1.45 (95 % CI, 1.07, 1.96), respectively. Dose-response analysis showed that every 1 mg/L increment in pre-procedural serum CRP level was associated with a significant 12 % increase in the risk of MACEs. In spite of heterogeneity across the included studies, this meta-analysis suggests that pre-procedural serum CRP level is a valuable predictor of MACEs in patients undergoing PCI.

A pharmacodynamic study of the optimal P2Y12 inhibitor regimen for East Asian patients with acute coronary syndrome

BACKGROUND/AIMS

Newer P2Y12 inhibitors, such as prasugrel and ticagrelor, have greater antiplatelet efficacy but may increase the risk of bleeding. In this study, we compared the pharmacodynamic efficacy of prasugrel and ticagrelor in East Asian patients with acute coronary syndrome (ACS).

METHODS

We selected 83 ACS patients undergoing percutaneous coronary intervention who were discharged with 90 mg ticagrelor twice daily (n = 24), 10 mg prasugrel daily (n = 39) or 5 mg prasugrel daily (n = 20). After 2 to 4 weeks, on-treatment platelet reactivity (OPR) was assessed in terms of P2Y12 reaction units (PRUs) using the VerifyNow P2Y12 assay (Accumetrics). We compared East Asian (85 < PRU ≤ 275) and Caucasian (85 < PRU ≤ 208) criteria for assessing the therapeutic window of OPR.

RESULTS

OPR was lowest in the ticagrelor group, followed by the 10 mg prasugrel and 5 mg prasugrel groups (49.1 ± 29.9 vs. 83.7 ± 57.1 vs. 168.5 ± 60.8, respectively; p < 0.001). The 5 mg prasugrel group had the highest proportion of patients with OPR values within the therapeutic window, followed by the 10 mg prasugrel and ticagrelor groups (90.0% vs. 46.2% vs. 12.5%, respectively; p < 0.001 for East Asian criteria; 60.0% vs. 43.6% vs. 12.5%, respectively; p < 0.001 for Caucasian criteria).

CONCLUSIONS

Short-term administration of 5 mg prasugrel facilitated maintenance within the therapeutic window of OPR compared with the 10 mg prasugrel and ticagrelor groups. Thus, 5 mg prasugrel daily may be the optimal antiplatelet regimen for stabilized East Asian ACS patients.

Temporal variability in the antiplatelet effects of clopidogrel and aspirin after elective drug-eluting stent implantation. An ADAPT-DES substudy

Given conflicting data on temporal variability in pharmacodynamic platelet responses to clopidogrel, we investigated platelet reactivity on clopidogrel and aspirin for up to six months after elective percutaneous coronary intervention (PCI) with drug-eluting stents. Platelet reactivity was determined in 102 patients before loading with clopidogrel and aspirin, and on maintenance therapy after PCI on day 1, at one month and six months by VerifyNow™ P2Y12 and Aspirin assays and by residual platelet aggregation (RPA) on light transmission aggregometry using adenosine diphosphate and arachidonic acid. By VerifyNow testing, median (interquartile range) P2Y12 reaction units (PRU) on clopidogrel were 166 (90-234), 195 (124-257), and 198 (141-252) on day 1, one month and six months after PCI, respectively (p=0.005 day 1 to 1 month, and p=0.86 1 month to 6 months). Using a cut-off of > 208 PRU, 35 % of patients had high platelet reactivity (HPR) to clopidogrel on day 1, 43 % at one month, and 46 % at six months after PCI. Between day 1 and six months after PCI, 38.2 % of patients changed clopidogrel responder status at least once. Other cut-offs and RPA yielded similar results. Platelet inhibition by aspirin was consistent over time with only five patients being characterised as having HPR. Considerable variation in individual on-clopidogrel platelet reactivity was present during both the subacute and the late phases of maintenance therapy after elective PCI. Hence, the utility of contemporary platelet function testing to guide antiplatelet therapy may be limited.

Personalized antiplatelet therapy with P2Y12 receptor inhibitors: benefits and pitfalls

Antiplatelet therapy with P2Y₁₂ receptor inhibitors has become the cornerstone of medical treatment in patients with acute coronary syndrome, after percutaneous coronary intervention and in secondary prevention of atherothrombotic events. Clopidogrel used to be the most broadly prescribed P2Y₁₂ receptor inhibitor with undisputable benefits especially in combination with aspirin, but a considerable number of clopidogrel-treated patients experience adverse thrombotic events in whom insufficient P2Y₁₂-inhibition and a consequential high on-treatment platelet reactivity is a common finding. This clinically relevant limitation of clopidogrel has driven the increased use of new antiplatelet agents. Prasugrel (a third generation thienopyridine) and ticagrelor (a cyclopentyl-triazolo-pyrimidine) feature more potent and predictable P2Y₁₂-inhibition compared to clopidogrel, which translates into improved ischemic outcomes. However, excessive platelet inhibition and consequential low on-treatment platelet reactivity comes at the price of increased risk of major bleeding. The majority of randomized clinical trials failed to demonstrate improved clinical outcomes with platelet function testing and tailored antiplatelet therapy, but results of all recent trials of potent antiplatelets and prolonged antiplatelet durations point towards a need for individualized antiplatelet approach in order to decrease thrombotic events without increasing bleeding. This review focuses on potential strategies for personalizing antiplatelet treatment.

The prognostic impact of high on-treatment platelet reactivity with aspirin or ADP receptor antagonists: systematic review and meta-analysis

OBJECTIVE

Negative results of recent randomized clinical trials testing the hypothesis of target therapy for patients with high on-treatment platelet reactivity (HOPR) have questioned its independent impact on clinical outcomes. 26 studies with 28.178 patients were included, with a median age of 66.8 (64-68) and 22.7% (22.4-27.8), of female gender. After a median follow-up of 1 year (0.1-1), cardiac adverse events occurred in 8.3% (3-11; all results are reported as median and interquartile range) of patients. Pooling all studies together, on-treatment platelet reactivity significantly increased the risk of adverse events (OR 1.33 [1.09, 1.64], I(2) = 0%). However, a sensitivity analysis showed that HOPR did not increase the risk of adverse events for patients with ACS, AMI, or stable angina as well as patients resistant to aspirin, ADP antagonists, or both. For all studies, publication bias was formally evident; after adjusting for this, HOPR did not significantly increase adverse cardiac events (OR 1.1 : 0.89-1.22, I(2) 0%).

CONCLUSIONS

After adjusting for clinical confounders (like risk factors and clinical presentation) and for relevant publication bias, HOPR was not an independent prognostic indicator in unselected patients with both stable and unstable coronary disease for an adverse cardiac event. The clinical importance of HOPR for high-risk populations remains to be assessed.

Global platelet hyperreactivity and elevated C-reactive protein levels predict long term mortality in STEMI patients

BACKGROUND

Data on long term - more than 1-year - prognostic value of global platelet reactivity (G-HPR) - by adenosine diphosphate (ADP) and arachidonic acid (AA) - in patients with STEMI undergoing PCI are limited. High C-reactive protein (CRP) levels have been suggested to be associated with post-PCI atherothrombotic events. Our aim was to evaluate the long-term prognostic impact of G-HPR and CRP levels in STEMI patients.

METHODS AND RESULTS

We evaluated 494 STEMI patients (366 M/128 F; age: 65.8 ± 12.4 yrs) undergoing PCI with stent implantation. At a median follow-up of 2.3 years (1.09-4.06), in 58 patients we documented cardiovascular death (11.7%). Platelet reactivity was assessed by light transmission aggregometry by 1mM AA (AA-LTA) and 10 microM ADP (ADP-LTA). By the ROC curve analysis, 17%, 52% and 12 mg/L were found to be the values of AA-LTA, ADP-LTA and CRP associated with the highest specificity and sensitivity for death. G-HPR was defined as the presence of both AA-LTA ≥ 17% and ADP-LTA ≥ 52%. At Cox regression analysis adjusted for age, sex, cardiovascular risk factors, multivessel disease, ejection fraction, renal insufficiency, G-HPR and elevated CRP levels were associated with long-term mortality [HR=1.78 (95%CI 1.04-3.03), p=0.036 and HR=2.91 (1.54-5.52, p=0.001), respectively]. The contemporary presence of G-HPR and elevated CRP levels was associated with the highest risk of death [HR=5.1 (95%CI 1.9-13.4), p=0.001].

CONCLUSION

G-HPR and CRP are independent long-term prognostic markers in STEMI patients. The contemporary presence of G-HPR and CRP identifies a subgroup of patients at significantly higher risk of cardiovascular death.

Risk of stroke in patients with high on-clopidogrel platelet reactivity to adenosine diphosphate after percutaneous coronary intervention

Several prospective studies have shown that high on-clopidogrel platelet reactivity (HPR) in patients undergoing percutaneous coronary intervention (PCI) is a risk factor for ischemic events. All studies were insufficiently powered to detect differences in stroke between patients with HPR and those without. Therefore, we performed a systematic review and meta-analysis of available publications aimed at determining whether patients undergoing PCI with HPR are also at increased risk of stroke. We searched for prospective studies enrolling patients undergoing PCI and treated with aspirin and clopidogrel that reported on clinical relevance of HPR to adenosine diphosphate. Study end point was the rate of stroke. We also investigated whether there was an interaction on the relative risk of stroke between HPR, clinical presentation, duration of follow-up, or laboratory methods. Fourteen studies including 11,959 patients were deemed eligible. On pooled analysis, the risk of stroke was higher in patients with HPR compared with patients with no HPR (1.2% vs 0.7%, relative risk on fixed effect 1.84, 95% confidence interval 1.21 to 2.80). There was no heterogeneity among the studies (I(2) = 0%, p = 0.5). Clinical presentation (p = 0.39 for interaction), duration of follow-up (p = 0.87 for interaction), and laboratory method for detection of HPR (p = 0.99 for interaction) did not affect the relative increase in the risk of stroke in patients with HPR compared with patients with no HPR. In conclusion, in patients with coronary artery disease undergoing PCI, the presence of HPR to adenosine diphosphate is a risk factor for stroke.

Sex difference in clinical outcomes after percutaneous coronary intervention in Korean population

BACKGROUND

Conflicting data on sex-based differences in outcomes after percutaneous coronary intervention (PCI) among Western population exist. Little is known about the nature of sex-specific PCI outcomes in an Asian population.

METHODS

We performed a pooled analysis using 23,604 patients from 11 prospective PCI clinical studies performed in Korea. The primary outcome was a major cardiovascular event, defined as composite of cardiovascular death, myocardial infarction, stent thrombosis, or stroke. Secondary outcomes were all-cause mortality and target vessel revascularization.

RESULTS

Thirty-day and 2-year rates of major cardiovascular events were more frequent in women than in men, mainly because of a higher incidence of periprocedural myocardial infarction in women (30-day: 9.2% vs 7.1%; 2-year: 11.2% vs 8.9%). After multivariable adjustment, women had significantly higher risks of 30-day (hazard ratio [HR] 1.27, 95% CI 1.19-1.36) and 2-year major cardiovascular events (HR 1.21, 95% CI 1.13-1.30). Unadjusted 30-day and 2-year all-cause mortality was similar between women and men (30-day: 0.5% vs 0.4%; 2-year: 2.8% vs 2.8%). However, after multivariable adjustment, women had a lower adjusted risk of 2-year death (HR 0.82, 95% CI 0.77-0.87). No sex-based difference was observed for target vessel revascularization (HR 1.07, 95% CI 0.91-1.25). Overall, sex-specific findings for outcomes were consistent across multiple patient subgroups.

CONCLUSION

Among Korean population undergoing contemporary PCI, women have a significantly higher risk of short- and long-term major cardiovascular events than do men but have better long-term survival.

Association of P2Y12 gene promoter DNA methylation with the risk of clopidogrel resistance in coronary artery disease patients

Background. Clopidogrel inhibits the ADP receptor P2Y12 to keep down the platelet aggregation. The goal of our study is to investigate the contribution of P2Y12 promoter DNA methylation to the risk of clopidogrel resistance (CR). Methods. The platelet functions were measured by the VerifyNow P2Y12 assay. Applying the bisulfite pyrosequencing technology, DNA methylation levels of two CpG dinucleotides on P2Y12 promoter were tested among 49 CR cases and 57 non-CR controls. We also investigated the association among P2Y12 DNA methylation, various biochemical characteristics, and CR. Result. Lower methylation of two CpGs indicated the poorer clopidogrel response (CpG1, P = 0.009; CpG2, P = 0.022) in alcohol abusing status. Meanwhile CpG1 methylation was inversely correlated with CR in smoking patients (P = 0.026) and in subgroup of Albumin < 35 (P = 0.002). We observed that the level of DNA methylation might be affected by some clinical markers, such as TBIL, LEVF, Albumin, AST. The results also showed that the quantity of stent, fasting blood-glucose, and lower HbAC1 were the predictors of CR. Conclusions. The evidence from our study indicates that P2Y12 methylation may bring new hints to elaborate the pathogenesis of CR.

Evolving management of patients treated by drug-eluting stent: prevention of late events

SUMMARY

Drug eluting stents (DES) were introduced in clinical practice to overcome the problem of in-stent restenosis (ISR) that limited the overall efficacy of percutaneous coronary revascularization with bare metal stent (BMS). Long-term outcome data confirm a sustained benefit of DES as compared with BMS. However, this benefit is mainly evident in the first year of follow-up. Indeed, DES-related events may extend over this time, due to late events (late ISR and/or very late stent thrombosis). Prevention of late failure of DES may become a specific therapeutic target.

Effect of platelet reactivity, endothelial function, and inflammatory status on outcomes in patients with stable angina pectoris on clopidogrel therapy

Although high on-treatment platelet reactivity (HTPR) is an important predictor of clinical outcomes in patients undergoing coronary stenting, it is unknown whether endothelial dysfunction and HTPR are associated. We examined the platelet function, peripheral vascular function, endothelial progenitor cell (EPC) number, platelet activation markers, high-sensitivity C-reactive protein (hs-CRP) level, and clinical outcomes in patients receiving chronic clopidogrel therapy. We consecutively enrolled 91 patients who underwent follow-up angiography because of chest discomfort. All patients took aspirin and clopidogrel for an average of 498 ± 138 days. Platelet reactivity was assessed by light transmittance aggregometry (maximal platelet aggregation by 5 μmol/L of adenosine diphosphate ≤50% in group 1 [optimal response] and >50% as group 2 [HTPR]). Flow-mediated dilation of the brachial artery and brachial-ankle pulse wave velocity (PWV), numbers of EPCs isolated from peripheral blood, platelet activation markers (soluble CD40 ligand and soluble P-selectin), and hs-CRP levels were assessed before follow-up angiography. There were no significant differences in baseline characteristics and previous percutaneous coronary intervention (PCI) data between groups 1 (n = 59) and 2 (n = 32). Group 2 showed poorer flow-mediated dilation (6.1 ± 4.1% vs 12.9 ± 6.2%, p <0.001), pulse wave velocity (1925.4 ± 362.2 vs 1571.0 ± 306.5 ms, p <0.001), and lower circulating EPCs by flow cytometry (21.9 ± 14.7 vs 65.2 ± 30.1 per 10 fields, p <0.001) compared with group 1. Significantly higher levels of soluble CD40 ligand, soluble P-selectin, and hs-CRP were observed in group 2. In multivariate analysis, elevated hs-CRP level, but not HTPR, was independently associated with repeated PCI. In patients with angina, HTPR was associated endothelial dysfunction and elevated hs-CRP, although elevated hs-CRP level was significantly associated with poorer outcomes.

Cytochrome P450 3A4*22, PPAR-α, and ARNT polymorphisms and clopidogrel response

Recent candidate gene studies using a human liver bank and in vivo validation in healthy volunteers identified polymorphisms in cytochrome P450 (CYP) 3A4 gene (CYP3A4*22), Ah-receptor nuclear translocator (ARNT), and peroxisome proliferator-activated receptor-α (PPAR-α) genes that are associated with the CYP3A4 phenotype. We hypothesized that the variants identified in these genes may be associated with altered clopidogrel response, since generation of clopidogrel active metabolite is, partially mediated by CYP3A activity. Blood samples from 211 subjects, of mixed racial background, with established coronary artery disease, who had received clopidogrel, were analyzed. Platelet aggregation was determined using light transmittance aggregometry (LTA). Genotyping for CYP2C19*2, CYP3A4*22, PPAR-α (rs4253728, rs4823613), and ARNT (rs2134688) variant alleles was performed using Taqman® assays. CYP2C19*2 genotype was associated with increased on-treatment platelet aggregation (adenosine diphosphate 20 μM; P=0.025). No significant difference in on-treatment platelet aggregation, as measured by LTA during therapy with clopidogrel, was demonstrated among the different genotypes of CYP3A4*22, PPAR-α, and ARNT. These findings suggest that clopidogrel platelet inhibition is not influenced by the genetic variants that have previously been associated with reduced CYP3A4 activity.

Combination of high on-treatment platelet aggregation and low deaggregation better predicts long-term cardiovascular events in PCI patients under dual antiplatelet therapy

High on-treatment platelet reactivity is associated with short-term major cardiovascular (CV) events in patients undergoing percutaneous coronary intervention (PCI). Maximum and final aggregation assessed by light transmission aggregometry (LTA) have both been used to predict short-term outcome after PCI, however their long-term prognostic impact remains controversial. There is currently no information regarding the prognostic role of deaggregation and its added value in combination with established aggregation parameters. About 1279 patients with symptomatic coronary artery disease (CAD) undergoing PCI were enrolled in this monocentric study. On-treatment platelet aggregation under clopidogrel maintenance therapy, as well as deaggregation was determined by maximum and final aggregation (5 min after adding of the agonist). Deaggregation was defined as slope of the tangent between Aggmax +0.5 min. Primary endpoints were the composite of myocardial infarction, stroke, and CV death or stent thrombosis according to the ARC criteria. Low deaggregation, defined as values in the lowest tertile (<1.5), was more frequent in patients with acute coronary syndromes (ACS) compared to patients with stable angina pectoris (SAP), ACS: 29.6% vs. SAP: 22.0%, p = 0.001. The combination of high on-treatment platelet reactivity, defined by the upper tertile of Aggmax and low deaggregation, was associated with significantly increased risk for combined long-term CV events. The combination of low deaggregation and high on-treatment platelet reactivity is associated with higher risk for recurrent events in patients with CAD undergoing PCI. Thus, deaggregation might be a more sensitive parameter providing added value in terms of risk prediction for long-term recurrent CV events in relation with established aggregation parameters.

Influence of platelet reactivity and inflammation on peri-procedural myonecrosis in East Asian patients undergoing elective percutaneous coronary intervention

BACKGROUND AND OBJECTIVES

The contribution of multiple risk factors to peri-procedural myocardial infarction (PMI) in East Asians remains controversial. To assess the influence of clinical or laboratory covariates on PMI in these patients.

METHODS

Stable patients (n=341) undergoing elective percutaneous coronary intervention (PCI) were enrolled. Platelet reactivity was measured by conventional aggregometry and VerifyNow. Inflammation markers and lipid profile were determined by standard methods. PMI was defined according to Universal definition (troponin I or CK-MB ≥ 3 times the 99th percentile of the upper reference limit).

RESULTS

PMI (defined by troponin I and CK-MB) occurred in 47 (13.8%) and 30 (8.8%) patients, respectively. There was no significant difference in ADP-induced platelet reactivity between patients with vs. without PMI. Patients with PMI (troponin I) had higher levels of 6 μg/mL collagen-induced platelet aggregation (PA) and VerifyNow 'BASE' compared with those without PMI. The combination of '6 μg/mL collagen-induced PA>40%'+'BASE>318' (odds ratio, 14.08; 95% confidence intervals, 1.68 to 111.11; p=0.015) or 'WBC>6550/mm(3)'+'C-reactive protein>2.3mg/L' (odds ratio, 7.75; 95% confidence intervals, 2.49 to 24.39; p<0.001) was associated with an increased risk of PMI (troponin I). The greatest likelihood ratio was observed when cholesterol, inflammation marker and platelet function were combined together.

CONCLUSION

This is the first study to demonstrate that heightened platelet responsiveness to collagen and thrombin may be a risk factor for myonecrosis in patients undergoing elective PCI. The utility of the combining measures of platelet function, inflammation and cholesterol to enhance risk stratification and thus facilitate personalized therapy deserves further study.

C-reactive protein and fibrin clot strength measured by thrombelastography after coronary stenting

Inflammation is implicated in the progression of coronary artery disease and the molecular processes of inflammation and thrombosis are closely intertwined. Elevated levels of C-reactive protein (CRP) have been associated with an elevated risk of adverse ischaemic events after coronary stenting and hypercoagulability. Heightened whole blood clot strength measured by thrombelastography (TEG) has been associated with adverse ischaemic events after stenting. We intended to examine the relationship of CRP to plasma fibrin clot strength in patients after coronary stenting. Plasma fibrin clot strength was measured by TEG in 54 patients 16-24 h after undergoing elective percutaneous coronary intervention (PCI). Coagulation was induced in citrated plasma by addition of kaolin and CaCl2. Plasma levels of CRP and fibrinogen were measured by enzyme-linked immunoassay. Increasing quartiles of CRP were associated with increasing levels of maximal plasma fibrin clot strength measured by TEG (P < 0.001) and increasing BMI (P = 0.04). Patients in the highest quartile of CRP had significantly higher maximal fibrin clot strength (G) than the patients in the lowest quartile (G: 3438 ± 623 vs. 2184 ± 576 dyn/cm, P < 0.0001). Fibrinogen concentration was not significantly different across quartiles of CRP (P = 0.97). Patients with established coronary artery disease undergoing coronary stenting who have elevated CRP after PCI exhibit heightened maximal plasma fibrin clot strength as compared with those with low CRP. Thrombotic risk associated with elevated CRP may be linked to procoagulant changes and high tensile fibrin clot strength independent of fibrinogen concentration.

Platelet reactivity and clinical outcomes after coronary artery implantation of drug-eluting stents (ADAPT-DES): a prospective multicentre registry study

BACKGROUND

The relation between platelet reactivity and stent thrombosis, major bleeding, and other adverse events after coronary artery implantation of drug-eluting stents has been incompletely characterised. We aimed to determine the relation between platelet reactivity during dual therapy with aspirin and clopidogrel and clinical outcomes after successful coronary drug-eluting stent implantation.

METHODS

ADAPT-DES was a prospective, multicentre registry of patients successfully treated with one or more drug-eluting stents and given aspirin and clopidogrel at 10-15 US and European hospitals. We assessed platelet reactivity in those patients after successful percutaneous coronary intervention using VerifyNow point-of-care assays, and assigned different cutoffs to define high platelet reactivity. The primary endpoint was definite or probable stent thrombosis; other endpoints were all-cause mortality, myocardial infarction, and clinically relevant bleeding. We did a propensity-adjusted multivariable analysis to determine the relation between platelet reactivity and subsequent adverse events. This study is registered with ClinicalTrials.gov, number NCT00638794.

FINDINGS

Between Jan 7, 2008, and Sept 16, 2010, 8665 patients were prospectively enrolled at 11 sites, of which 8583 were eligible. At 1-year follow-up, stent thrombosis had occurred in 70 (0·8%) patients, myocardial infarction in 269 (3·1%), clinically relevant bleeding in 531 (6·2%), and death in 161 (1·9%) patients. High platelet reactivity on clopidogrel was strongly related to stent thrombosis (adjusted HR 2·49 [95% CI 1·43-4·31], p=0·001) and myocardial infarction (adjusted HR 1·42 [1·09-1·86], p=0·01), was inversely related to bleeding (adjusted HR 0·73 [0·61-0·89], p=0·002), but was not related to mortality (adjusted HR 1·20 [0·85-1·70], p=0·30). High platelet reactivity on aspirin was not significantly associated with stent thrombosis (adjusted HR 1·46 [0·58-3·64], p=0·42), myocardial infarction, or death, but was inversely related to bleeding (adjusted HR 0·65 [0·43-0·99], p=0·04).

INTERPRETATION

The findings from this study emphasise the counter-balancing effects of haemorrhagic and ischaemic complications after stent implantation, and suggest that safer drugs or tailored strategies for the use of more potent agents must be developed if the benefits of greater platelet inhibition in patients with cardiovascular disease are to be realised.

FUNDING

Boston Scientific, Abbott Vascular, Medtronic, Cordis, Biosensors, The Medicines Company, Daiichi-Sankyo, Eli Lilly, Volcano, and Accumetrics.

Correlation of platelet reactivity and C-reactive protein levels to occurrence of peri-procedural myocardial infarction in patients undergoing percutaneous coronary intervention (from the ARMYDA-CRP study)

The incremental predictive value of high inflammatory status and high on-treatment platelet reactivity (HPR) on the occurrence of periprocedural myocardial infarction (PMI) after percutaneous coronary intervention (PCI) has not been characterized. The aim of this study was to evaluate the correlation of elevated C-reactive protein (CRP) level and/or HPR with the incidence of PMI in patients who undergo PCI. Five hundred consecutive patients treated with clopidogrel who underwent PCI had preprocedural measurement of CRP levels and platelet reactivity using the point-of-care VerifyNow P2Y12 assay. Elevated inflammatory status was defined as CRP >3 mg/L and HPR as P2Y12 reactivity units ≥240. The primary end point was the incidence of PMI in relation to platelet reactivity and/or inflammatory status. Rates of PMI were increased in patients with CRP levels >3 mg/L (10.9% vs 4.6% in those with normal levels, odds ratio 2.4, 95% confidence interval 1.2 to 4.5, p = 0.015) and in patients with HPR (11% vs 5.5% in those without HPR, odds ratio 2.2, 95% confidence interval 1.2-4.4, p = 0.018). The occurrence of PMI was highest in the subgroup with HPR and high inflammatory status (16.6% vs 3.6% in patients with CRP ≤3 mg/L and P2Y12 reactivity units <240, odds ratio 4.3, 95% confidence interval 1.5 to 12.6, p = 0.008). HPR in association with elevated CRP levels resulted in a significant increase in the discriminatory power of a model including clinical and procedural variables in predicting PMI (area under the curve 0.811, p = 0.041). In conclusion, in patients who undergo PCI, baseline stratification according to platelet reactivity and inflammatory status may identify those at higher risk for PMI.

Platelet function tests in clinical cardiology: unfulfilled expectations

This review is a critical evaluation of publications in the past decade on the usefulness of platelet function tests (PFTs) in clinical cardiology, in aiding diagnosis, predicting risk, and monitoring therapy. The ideal PFT should: 1) detect baseline platelet hyperreactivity; 2) allow individualization of antiplatelet medication; 3) predict thrombotic risk; and 4) predict bleeding risk. The practicalities of clinical cardiology demand rapid, accurate, and reliable tests that are simple to operate at the bedside and available 24 h a day, 7 days a week. Point-of-care PFTs most widely evaluated clinically include PFA-100 and VerifyNow. None of these tests can reliably detect platelet hyperreactivity and thus identify a prothrombotic state. Identification of antiplatelet nonresponsiveness or hyporesponsiveness is highly test specific, and does not allow individualization of therapy. The power of PFTs in predicting thrombotic events for a given individual is variable and often modest, and alteration of antithrombotic treatment on the basis of the results of PFTs has not been shown to alter clinical outcome. PFTs in current mainstream use cannot reliably assess bleeding risk. These tests have been in use for over a decade, but the hopes raised by PFTs in clinical practice remain unfulfilled. Although physiologically relevant measurement of platelet function now is more important than ever, a critical reappraisal of available techniques in light of clinical requirements is needed. The use of native blood, global stimulus instead of individual agonists, contribution of thrombin generation by activated platelets to the test results, and establishment of a PFT therapeutic range for each antiplatelet drug should be considered and is discussed.

Association of body mass index with major cardiovascular events and with mortality after percutaneous coronary intervention

BACKGROUND

Conflicting data exist regarding the relation between body mass index (BMI) and cardiovascular events and mortality after percutaneous coronary intervention.

METHODS AND RESULTS

We performed pooled analyses to evaluate the association between BMI (weight in kilograms divided by the square of the height in meters) and the risks of major cardiovascular events (defined as death from cardiovascular causes, nonfatal myocardial infarction, stent thrombosis, or stroke) and death among 23 181 patients from 11 prospective percutaneous coronary intervention studies. Overall, mean (±SD) BMI was 24.9±3.0. During follow-up (median, 2.1 years), 2381 patients had a major cardiovascular event, and 1004 patients died. After adjusting covariates, there was an inverse relationship between BMI and adverse outcomes. With a BMI of 22.5 to 24.9 as the reference category, the risk of major cardiovascular events was elevated among patients with a lower BMI (by a factor of 1.52 for a BMI <18.5; 1.05 for a BMI of 18.5-19.9; 1.03 for a BMI of 20.0-22.4); by contrast, the risk declined among patients with a higher BMI (by a factor of 0.97 for a BMI of 25.0-27.4; 0.97 for a BMI of 27.5-29.9; and 0.78 for a BMI of ≥30.0). In general, the hazard ratios for deaths were similar.

CONCLUSIONS

Among patients undergoing percutaneous coronary intervention, a low BMI was associated with increased risks of major cardiovascular events and death. However, there were no excess risks of these events associated with a high BMI.

Reduced antiplatelet effect of aspirin is associated with low-grade inflammation in patients with coronary artery disease

Inflammation has been proposed to modify platelet function. This may lead to increased platelet reactivity and reduced antiplatelet drug efficacy in patients with coronary artery disease (CAD). However, this hypothesis has not been investigated in stable CAD patients receiving aspirin as mono antiplatelet therapy. It was the objective of this study to investigate the association between platelet reactivity, the inflammatory markers high-sensitive C-reactive protein (hs-CRP) and interleukin-6 (IL-6), and platelet activation. We performed a cross-sectional study on 524 stable high-risk CAD patients. Among these, 91% had a history of myocardial infarction, 23% had type 2 diabetes, and 13% had both. All patients received 75 mg aspirin daily as mono antiplatelet therapy. Platelet reactivity was assessed by multiple electrode aggregometry (Multiplate®, MEA) and VerifyNow®. Inflammation was evaluated by hs-CRP and IL-6. Platelet activation was assessed by soluble P-selectin (sP-selectin), and cyclooxygenase-1 inhibition was evaluated by measurement of serum thromboxane B2. Hs-CRP levels were significantly higher in upper platelet reactivity tertile patients than in lower platelet reactivity tertile patients (p≤0.02). Similar results were obtained with IL-6, though not statististically significant (p≥0.15). Platelet activation evaluated by sP-selectin was significantly higher in patients with MEA reactivity levels in the upper tertile than in the lower tertile (p=0.0001). Optimal compliance was confirmed by low serum thromboxane B2 levels in all patients. In conclusion, increased levels of hs-CRP were associated with augmented platelet reactivity in stable high-risk CAD patients receiving aspirin as mono antiplatelet therapy. These findings may suggest that chronic low-grade inflammation reduce the antiplatelet effect of aspirin.

Frequency, causes, predictors, and clinical significance of peri-procedural myocardial infarction following percutaneous coronary intervention

AIMS

Peri-procedural myocardial infarction (MI) is a not infrequent complication of percutaneous coronary intervention (PCI), but conflicting information exists regarding incidence and prognostic impact of this event. We investigated frequency, causes, predictors, and clinical relevance of peri-procedural MI, using a large database.

METHODS AND RESULTS

We pooled individual patient-level data from 11 PCI studies in which peri-procedural creatine kinase-MB mass was routinely measured and mortality data were prospectively collected. Among 23 604 patients from 11 studies, 1677 {7.1% [95% confidence interval (CI) 6.8-7.5%]} had peri-procedural MI. The most common mechanism of peri-procedural MI was side-branch occlusion. Independent predictors of peri-procedural MI were older age, female gender, diabetes, hypertension, renal dysfunction, multivessel disease, left anterior descending artery disease, left main disease, bifurcation lesion, long lesion, drug-eluting stents, and number of stents. Follow-up varied from 1 year to 5 years. In a crude analysis, patients with peri-procedural MI had significantly a higher risk of mortality than those without peri-procedural MI [hazard ratio (HR) 1.47; 95% CI 1.24-1.74]. After adjustment for baseline covariates, peri-procedural MI was associated with an increased risk of mortality (HR 1.20; 95% CI 1.04-1.39).

CONCLUSION

Among patients undergoing PCI, the occurrence of peri-procedural MI measured by CK-MB mass assay was ~7%, and more than half of cases were associated with side-branch occlusion. Several higher risk patients, lesions, and procedural characteristics were independent predictors of peri-procedural MI. Peri-procedural MI was associated with an increase in mortality.

Differential prognostic impact of high on-treatment platelet reactivity among patients with acute coronary syndromes versus stable coronary artery disease undergoing percutaneous coronary intervention

BACKGROUND

High on-treatment platelet reactivity (HTPR) after clopidogrel is associated with a higher risk of cardiovascular events after percutaneous coronary intervention (PCI). However, it remains unclear whether HTPR is of similar prognostic value for different clinical presentations.

METHODS

We compared the prognostic impact of HTPR, measured by the VerifyNow P2Y12 assay (Accumetrics, San Diego, CA), on outcomes between 1,095 patients with acute coronary syndromes (ACS) and 1,329 patients with stable coronary artery disease (CAD) who were treated with PCI. Before PCI, patients received optimal clopidogrel treatment (75 mg daily for at least 5 days or if <5 days, 300-600 mg loading), and platelet reactivity was measured at 24 to 48 hours after PCI. The primary end point was a composite of death, myocardial infarction, stent thrombosis, or stroke.

RESULTS

During follow-up (median, 22.0 months), HTPR was independently associated with higher risks of the primary end point (hazard ratio [HR] 2.03, 95% CI 1.30-3.18, P = .002) and mortality (HR 3.46, 95% CI 1.18-10.18, P = .02) in patients with ACS. By contrast, for patients with stable CAD, HTPR was not associated with adjusted risks of the primary end point (HR 1.00, 95% CI 0.71-1.39, P = .98) or mortality (HR 0.74, 95% CI 0.36-1.51, P = .41). Significant interactions were present between HTPR status and clinical presentations for the primary end point (P = .02) and mortality (P = .04).

CONCLUSION

There was a substantial interaction between platelet reactivity on clopidogrel and clinical presentations on cardiovascular events after PCI. High on-treatment platelet reactivity was significantly associated with higher risks of cardiovascular events in ACS patients, whereas this association was absent in stable CAD patients.