Refining the role of antiplatelet therapy in medically managed patients with acute coronary syndrome

Consensus Document ANMCO/ANCE/ARCA/GICR-IACPR/GISE/SICOA: Long-term Antiplatelet Therapy in Patients with Coronary Artery Disease

Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor is the cornerstone of pharmacologic management of patients with acute coronary syndrome (ACS) and/or those receiving coronary stents. Long-term (>1 year) DAPT may further reduce the risk of stent thrombosis after a percutaneous coronary intervention (PCI) and may decrease the occurrence of non-stent-related ischaemic events in patients with ACS. Nevertheless, compared with aspirin alone, extended use of aspirin plus a P2Y12 receptor inhibitor may increase the risk of bleeding events that have been strongly linked to adverse outcomes including recurrent ischaemia, repeat hospitalisation and death. In the past years, multiple randomised trials have been published comparing the duration of DAPT after PCI and in ACS patients, investigating either a shorter or prolonged DAPT regimen. Although the current European Society of Cardiology guidelines provide a backup to individualised treatment, it appears to be difficult to identify the ideal patient profile which could safely reduce or prolong the DAPT duration in daily clinical practice. The aim of this consensus document is to review contemporary literature on optimal DAPT duration, and to guide clinicians in tailoring antiplatelet strategies in patients undergoing PCI or presenting with ACS.

Association Between Clinical Pathways Leading to Medical Management and Prognosis in Patients With NSTEACS

INTRODUCTION AND OBJECTIVES

A large proportion of patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) are initially selected for medical management (MM) and do not undergo coronary revascularization during or immediately after the index event. The aim of this study was to explore the clinical pathways leading to MM in NSTEACS patients and their influence on prognosis.

METHODS

Patient characteristics, pathways leading to MM, and 2-year outcomes were recorded in a prospective cohort of 5591 NSTEACS patients enrolled in 555 hospitals in 20 countries across Europe and Latin America. Cox models were used to assess the impact of hospital management on postdischarge mortality.

RESULTS

Medical management was the selected strategy in 2306 (41.2%) patients, of whom 669 (29%) had significant coronary artery disease (CAD), 451 (19.6%) had nonsignificant disease, and 1186 (51.4%) did not undergo coronary angiography. Medically managed patients were older and had higher risk features than revascularized patients. Two-year mortality was higher in medically managed patients than in revascularized patients (11.0% vs 4.4%; P < .001), with higher mortality rates in patients who did not undergo angiography (14.6%) and in those with significant CAD (9.3%). Risk-adjusted mortality was highest for patients who did not undergo angiography (HR = 1.81; 95%CI, 1.23-2.65), or were not revascularized in the presence of significant CAD (HR = 1.90; 95%CI, 1.23-2.95) compared with revascularized patients.

CONCLUSIONS

Medically managed NSTEACS patients represent a heterogeneous population with distinct risk profiles and outcomes. These differences should be considered when designing future studies in this population.

Oral antiplatelet agents for the management of acute coronary syndromes: A review for nurses and allied healthcare professionals

PURPOSE

We review the use of oral antiplatelet (OAP) therapies in acute coronary syndrome (ACS) management for nurse practitioners (NPs), focusing on current guideline recommendations.

DATA SOURCES

Treatment guidelines and clinical articles from PubMed.

CONCLUSIONS

Guidelines recommend that dual antiplatelet therapy with a P2Y₁₂ inhibitor and aspirin be initiated for ACS management. The P2Y₁₂ inhibitor clopidogrel has established efficacy, but is associated with suboptimal and delayed platelet inhibition and variability in response. The newer P2Y₁₂ inhibitors prasugrel and ticagrelor have demonstrated superior efficacy outcomes versus clopidogrel. Consequently, non-ST-segment elevation ACS (NSTE-ACS) guidelines now recommend that ticagrelor be used in preference to clopidogrel for patients treated with stents or managed medically. Because of their higher potency, prasugrel and ticagrelor are associated with increased bleeding rates versus clopidogrel, but with no increased risk of severe or life-threatening bleeding. Guidelines recommend dual antiplatelet therapy be continued ≥12 months in both medically managed and stented ACS patients, and in some cases beyond this, in absence of high bleeding risk. Updated guidelines assign preference to ticagrelor over clopidogrel for maintenance therapy in patients with NSTE-ACS and ST-elevation myocardial infarction.

IMPLICATIONS FOR PRACTICE

Enhanced NP understanding of OAP agents and current guidelines could contribute to improved ACS patient management.

Relationship between pharmacokinetics and pharmacodynamics of clopidogrel in patients undergoing percutaneous coronary intervention: comparison between vasodilator-stimulated phosphoprotein phosphorylation assay and multiple electrode aggregometry

ESSENTIALS: The reliability of platelet tests as markers of the variable bioavailability of clopidogrel is not yet defined. Kinetics of clopidogrel active metabolite (CAM) and platelet response were studied in ischemic heart disease. CAM plasma maximum concentration (Cmax ) predicted vasodilator-stimulated phosphoprotein (VASP-P). Timely performed VASP-P, not an aggregation-based test, may be a surrogate for clopidogrel bioavailability.

BACKGROUND

The high inter-individual variability in the inhibition of platelet function by clopidogrel is mostly explained by high variability in its transformation to an active metabolite (CAM). Objective We investigated the relations between pharmacokinetics and pharmacodynamics of CAM by comparing two methods of platelet function.

METHODS

We enrolled 14 patients undergoing percutaneous coronary interventions for non-ST-segment elevation acute coronary syndrome or inducible myocardial ischemia. Plasma concentrations of clopidogrel and CAM, phosphorylation of vasodilator-stimulated phosphoprotein (VASP-P), expressed as a platelet reactivity index (PRI) and whole-blood platelet aggregation (multiple electrode aggregometer, MEA) were measured before and after a 600-mg clopidogrel loading dose (nine time-points) and before and after 75-mg maintenance doses on days 2, 7 and 30.

RESULTS

Plasma concentrations of clopidogrel and CAM were highly variable. CAM reached maximal concentration (Cmax ) (median, 110.8 nm; range, 41.9-484.8) 0.5-2 h after the loading dose. A sigmoid dose-response curve defined the relations between CAMCmax and PRI after 3 to 24 h (IC50 , 459.6 nm; 95% confidence interval, 453.4-465.7; R(2) = 0.82). PRI was unchanged from baseline in patients with the lowest CAMCmax (< 83 nm, n = 7), indicating low sensitivity of VASP-P. PRI values were also predicted by CAMCmax at days 2, 7 and 30. Platelet aggregation measured by MEA did not show significant relations with either PRI or with CAM pharmacokinetics at any time-point.

CONCLUSIONS

After 600 mg clopidogrel, VASP-P, but not whole-blood platelet aggregation measured by MEA, is almost entirely predicted by CAMCmax . VASP-P could be useful in studies aimed at investigating relations between CAM bioavailability and clinical events.

Challenges and solutions in medically managed ACS in the Asia-Pacific region: expert recommendations from the Asia-Pacific ACS Medical Management Working Group

Acute coronary syndromes (ACS) remain a leading cause of mortality and morbidity in the Asia-Pacific (APAC) region. International guidelines advocate invasive procedures in all but low-risk ACS patients; however, a high proportion of ACS patients in the APAC region receive solely medical management due to a combination of unique geographical, socioeconomic, and population-specific barriers. The APAC ACS Medical Management Working Group recently convened to discuss the ACS medical management landscape in the APAC region. Local and international ACS guidelines and the global and APAC clinical evidence-base for medical management of ACS were reviewed. Challenges in the provision of optimal care for these patients were identified and broadly categorized into issues related to (1) accessibility/systems of care, (2) risk stratification, (3) education, (4) optimization of pharmacotherapy, and (5) cost/affordability. While ACS guidelines clearly represent a valuable standard of care, the group concluded that these challenges can be best met by establishing cardiac networks and individual hospital models/clinical pathways taking into account local risk factors (including socioeconomic status), affordability and availability of pharmacotherapies/invasive facilities, and the nature of local healthcare systems. Potential solutions central to the optimization of ACS medical management in the APAC region are outlined with specific recommendations.