Impact of Point-of-Care Platelet Function Testing Among Patients With and Without Acute Coronary Syndromes Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents (from the ADAPT-DES Study)

Stent Thrombosis Risk Over Time on the Basis of Clinical Presentation and Platelet Reactivity: Analysis From ADAPT-DES

OBJECTIVES

The aim of this study was to determine the risk period for increased stent thrombosis (ST) after percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS) and whether this increased risk is related to high platelet reactivity (HPR).

BACKGROUND

ST risk after PCI is higher among patients with ACS than those with stable ischemic heart disease. When ST risk is highest in patients with ACS and how that is affected by HPR is unknown.

METHODS

Using the ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) registry, ST rates during 2-year follow-up post-PCI with drug-eluting stents were compared among patients presenting with ACS (myocardial infarction [MI] or unstable angina) or stable ischemic heart disease (non-ACS). Landmark analyses were done at 30 days and 1 year post-PCI. Platelet reactivity on aspirin and clopidogrel post-PCI was assessed using VerifyNow assays.

RESULTS

Of 8,582 patients, 2,063 presented with MI, 2,370 with unstable angina, and 4,149 with non-ACS. Incidence rates of HPR were 48.0%, 43.3%, and 39.8%, respectively (p < 0.001). Within the first 30 days post-PCI, patients presenting with MI had increased ST risk compared with patients with non-ACS (hazard ratio [HR]: 4.52; 95% confidence interval [CI]: 2.01 to 10.14; p < 0.001). After 30 days, relative ST risks were progressively lower and no longer significant between groups (31 days to 1 year post-PCI: HR: 1.97; 95% CI: 0.80 to 4.85; >1 year post-PCI: HR: 0.89; 95% CI: 0.27 to 2.92). The elevated ST risk in patients with MI within 30 days was largely confined to those with HPR on clopidogrel (HR: 5.77; 95% CI: 2.13 to 15.63; p < 0.001).

CONCLUSIONS

Among patients undergoing PCI, rates of ST during 2-year follow-up were highest in those with MI and lowest in those with non-ACS. Increased ST risk in patients with MI was greatest in the first 30 days post-PCI and was observed predominantly among those with increased HPR on clopidogrel. These findings emphasize the importance of adequate P2Y₁₂ inhibition after MI, especially within the first 30 days after stent implantation.

Viscoelastic Hemostatic Assays and Platelet Function Testing in Patients with Atherosclerotic Vascular Diseases

Platelets play crucial role in acute vascular atherosclerotic diseases, including myocardial infarction and stroke. Additionally, platelet aggregation is a key target of antiplatelet agents, forming the keystone of pharmacotherapy of various atherosclerotic cardiovascular diseases. Thromboelastography and thromboelastometry, representing currently available viscoelastic hemostatic assays (VHA), are designed as whole blood, real-time analyzers of clot formation and clot resolution. These assays could, in theory, overcome some limitations of currently available platelet function testing assays. This article reviews the current experience with the use of VHA for platelet function testing and for monitoring of the response to antiplatelet therapy.

Comparison of Clinical Characteristics of Stent Thrombosis Between the Right Coronary Artery and the Left Coronary Artery - A Subanalysis of the REAL-ST Registry

BACKGROUND

Stent thrombosis (ST) remains a severe complication following stent implantation. We previously reported the risk factors for ST after 2nd-generation drug-eluting stent (DES) in the REAL-ST (Retrospective Multicenter Registry of ST After First- and Second-Generation DES Implantation) registry.Methods and Results:In this subanalysis, we aimed to reveal the difference in ST between right coronary (RCA) and left (LCA) coronary arteries. A total of 307 patients with ST were divided into the RCA-ST group (n=93) and the LCA-ST group (n=214). Multivariate analysis revealed younger age (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.93-0.99, P=0.01), ostial lesion at the time of index percutaneous coronary intervention (OR 4.37, 95% CI 1.43-13.33, P=0.01), bifurcation lesion at the time of index PCI (OR 0.05, 95% CI 0.02-0.12, P<0.01), chronic total occlusion (CTO) lesion at the time of index PCI indication (OR 4.19, 95% CI 1.05-16.71, P=0.04), and use of prasugrel at the time of ST (OR 7.30, 95% CI 1.44-36.97, P=0.02) were significantly associated with RCA-ST.

CONCLUSIONS

Younger age, ostial or CTO lesion, and use of prasugrel at the time of ST were prominent factors in RCA-ST, whereas bifurcation lesion was associated with LCA-ST. We should pay attention to the differences between RCA-ST and LCA-ST to prevent ST.