How to Manage Antiplatelet Therapy for Stenting in a Patient Requiring Oral Anticoagulants

In-stent thrombosis when switching ticagrelor to clopidogrel after percutaneous coronary intervention

Dual antiplatelet therapy with aspirin and a P2Y12 receptor blocker has been proven to reduce subsequent cardiovascular events and in-stent thrombosis in patients undergoing percutaneous coronary intervention. Newer P2Y12 antagonists with faster onset and greater inhibition of platelet activity have improved cardiovascular outcomes but have created uncertainty with the appropriate dosing when switching between agents. Currently, there are no evidence-based guidelines to aid clinicians when switching between P2Y12 receptor blockers. Here we describe two patients that developed in-stent thrombosis when switching from ticagrelor to clopidogrel using a 300 mg clopidogrel loading dose. Both patients presented with ST elevation myocardial infarction and underwent stent placement but then developed in-stent thrombosis 48 hours after switching from ticagrelor to clopidogrel. These cases illustrate the severe consequences of suboptimal platelet inhibition and the need for prospective trials thoroughly powered to assess clinical outcomes in order to determine the most appropriate strategy when switching from ticagrelor to clopidogrel.

Pharmacodynamic and clinical implications of switching between P2Y12 receptor antagonists: considerations for practice

Dual antiplatelet therapy with aspirin and a P2Y12 receptor antagonist, either clopidogrel or the newer more potent agents prasugrel or ticagrelor, is standard therapy in patients receiving a coronary stent and those with a recent acute coronary syndrome. Switching antiplatelet drug regimen may be required in some patients for efficacy, safety, adherence, and cost considerations. However, there are potential concerns when switching from one agent to another that gaps in effective antiplatelet inhibition could lead to thrombotic events, and overlap of agents might cause excessive platelet inhibition thereby increasing the risk of bleeding. This review considers pharmacodynamic and clinical data to guide clinicians when switching between antiplatelet drugs is considered. Loading dose of the new agent should be considered in nearly all situations to avoid any possible gap in adequate platelet inhibition, as overlap of the 2 agents is unlikely to result in bleeding in excess of that with the more potent drug.

Evolving antithrombotic strategies in patients with atrial fibrillation undergoing percutaneous coronary intervention: results from a survey among US cardiologists

BACKGROUND

Many patients treated with oral anticoagulants for atrial fibrillation undergo percutaneous stent implantation, where dual antiplatelet therapy (DAPT) is also recommended. The current evidence to support triple oral antithrombotic therapy (TOAT) in these patients is limited, and new strategies are being discussed to optimize outcomes.

HYPOTHESIS

There will be variation in antithrombotic strategies in patients with atrial fibrillation needing stenting.

METHODS

We surveyed US-based cardiologists serving as clinical investigators in academic sites and posted an online "question of the month" on cardiosource.org.

RESULTS

Seventy-five (10.7%) responses were received to the email survey and 119 to the online question. Bare-metal stenting (BMS) was a priori preferred over drug-eluting stenting (DES) for 50.6% of patients. Only 8.8% of the responders chose newer anticoagulants in addition to DAPT as the preferred oral anticoagulant. For duration of TOAT, 79.4% of physicians recommended stopping DAPT at 1 month when BMS was used in patients presenting without acute coronary syndrome (ACS) vs 57.4% in patients with ACS. In patients implanted with a DES, 73.5% and 76.5% preferred stopping DAPT at 6 to 12 months (no ACS vs ACS, respectively). When asked which of the 2 antiplatelet agents they would recommend stopping after the above durations, 50% chose to quit aspirin.

CONCLUSIONS

The survey highlights an interest in the new strategy of dropping aspirin, but the lack of concrete evidence triggers undesired diversity in clinical approaches. High-quality data on the efficacy and safety of such interventions are needed to further consolidate these approaches.

Protecting the Brain and the Heart

Novel anticoagulants (NOACs) are the recent therapeutic breakthrough in the prophylaxis of stroke in patients with nonvalvular atrial fibrillation (NVAF). Patients with NVAF seem to have a high atherosclerotic burden, but it has not yet been established whether these agents also protect against cardiovascular disease (CVD). Different NOACs could have cardioprotective properties of different importance, but data come only from indirect comparisons. Patients with NVAF are at risk of stroke when there is concomitant atherosclerosis that also necessitates optimal treatment to reduce CVD risk. Combining antiplatelets with anticoagulants is a common clinical scenario and not always justified by current data and guidelines, putting patients at unnecessary bleeding risk. This review provides current knowledge about the cardioprotective properties of NOACs, the clinical importance of the link between CVD and NVAF, and the pitfalls of combining antiplatelet therapy with warfarin or NOACs.