Clopidogrel cessation triggers aspirin rebound in patients with coronary stent

No rebound effect after a course of clopidogrel in patients with acute TIA or minor stroke

BACKGROUND AND PURPOSE

Previous studies demonstrated that discontinuation of clopidogrel in patients after ACS was associated with a rebound increase in risk of recurrent events. In this study, we aimed to investigate the rebound effect after discontinuation of clopidogrel therapy in patients with TIA or stroke.

METHODS

All patients with minor stroke or TIA were recruited from the Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events (CHANCE) trial. Patients were divided into two groups: patients who discontinued clopidogrel and switched to aspirin therapy   (Clopidogrel Discontinuation Group) and patients who continued one mono-antiplatelet therapy (non-Clopidogrel Discontinuation Group) during 90-180  days. The outcomes included risks of recurrent ischemic stroke, recurrent TIA, and composite events during 90-180  days. The prevalence of each outcome was compared between two groups for every 30 days. Further subgroup analysis was conducted in patients with and without CYP2C19 loss-of-function alleles.

RESULTS

Among the 3456 patients included, a total of 10 patients in the Clopidogrel Discontinuation Group and 11 patients in the non-Clopidogrel Discontinuation Group presented ischemic stroke recurrence during the 90-180-day period. The inter-group comparisons were not significant in each 30 days. Similar results were found for recurrent stroke, recurrent TIA, and composite events in these two groups, which were also found in CYP2C19 subgroup analysis.

CONCLUSIONS

No rebound increase in the risk of ischemic stroke and composite events was found during the 90 days after discontinuation of clopidogrel therapy in patients with TIA or minor stroke in the CHANCE trial.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00979589.

Lipids and Antiplatelet Therapy: Important Considerations and Future Perspectives

Lipids play an essential role in platelet functions. It is known that polyunsaturated fatty acids play a role in increasing platelet reactivity and that the prothrombotic phenotype plays a crucial role in the occurrence of major adverse cardiovascular events. The ongoing increase in cardiovascular diseases’ incidence emphasizes the importance of research linking lipids and platelet function. In particular, the rebound phenomenon that accompanies discontinuation of clopidogrel in patients receiving dual antiplatelet therapy has been associated with changes in the lipid profile. Our many years of research underline the importance of reduced HDL values for the risk of such a rebound effect and the occurrence of thromboembolic events. Lipids are otherwise a heterogeneous group of molecules, and their signaling molecules are not deposited but formed “on-demand” in the cell. On the other hand, exosomes transmit lipid signals between cells, and the profile of such changes can be monitored by lipidomics. Changes in the lipid profile are organ-specific and may indicate new drug action targets.

Risk of Early Adverse Events After Clopidogrel Discontinuation in Patients Undergoing Short-Term Dual Antiplatelet Therapy: An Individual Participant Data Analysis

OBJECTIVES

The study sought to evaluate the presence of a clinically relevant rebound phenomenon after dual antiplatelet therapy (DAPT) discontinuation in randomized trials.

BACKGROUND

It is currently unknown whether clopidogrel discontinuation after short-term DAPT is associated with an early hazard of ischemic events.

METHODS

The authors performed an individual participant data analysis and aggregate meta-analysis. The primary outcome was major adverse cardiac and cerebrovascular events (MACCE), defined as the composite of cardiac death, myocardial infarction (MI), or stroke.

RESULTS

The study included 11,473 PCI patients with individual participant data from 6 randomized trials comparing short-term DAPT (3 or 6 months) versus long-term DAPT (12 months or more). During the first 90 days following clopidogrel discontinuation, there was no significant increase in the risk of MACCE between patients randomized to short-term DAPT compared with long-term DAPT (hazard ratio [HR]: 1.18; 95% confidence interval [CI]: 0.71 to 1.98; p = 0.52; absolute risk difference 0.10%; 95% CI: -0.16% to 0.36%). The risk of MI or stent thrombosis was similar among patients randomized to short-term DAPT versus long-term DAPT (HR: 0.93; 95% CI: 0.46 to 1.90; p = 0.85). In the aggregate data meta-analysis of 11 trials including 38,919 patients, a higher risk of early MACCE was observed after long-term (≥12 months) DAPT duration (HR: 2.28; 95% CI: 1.69 to 3.09; p < 0.001) but not short-term (<12 months) DAPT duration (HR: 1.08; 95% CI: 0.67 to 1.74; p for interaction = 0.036).

CONCLUSIONS

Among patients undergoing PCI with predominantly new-generation DES, discontinuation of clopidogrel after 3 or 6 months DAPT duration was not associated with an early increase in adverse clinical events. An early increase in MACCE was observed after long-term (≥12 months) DAPT exposure.

Sustained increase in platelet aggregation after the cessation of clopidogrel

This study shows that the abrupt cessation of one-year clopidogrel treatment was not associated with thrombotic events in a prospective, multicentre study that enrolled 200 patients subjected to coronary stent implantation and treated with aspirin + clopidogrel 1 year after the stent placement. The aim of the study was to investigate the causes of a sustained increase of platelet aggregability, considering that the values of platelet aggregation stimulated with ADP + PGE1 (ADPHS values) significantly increased 10-90 days after the cessation of clopidogrel. Values of platelet aggregation induced by thrombin receptor activating peptide (TRAP values) and arachidonic acid (ASPI values) were divided into quartiles on the basis of ADPHS values 10 days after stopping clopidogrel (ADPHS10 ). There was a significant difference between TRAP values divided into quartiles according to ADPHS10 , 10, 45 and 90 days after stopping clopidogrel (P < 0.001, all), and ASPI values across the same quartiles 10 and 45 days after the cessation of clopidogrel (P = 0.028 and 0.003). The results of the study indicate that patients with early pronounced rebound phenomena to clopidogrel termination have a long-term (at least 90 days) increased platelet aggregation to other agonists such as thrombin-related activated protein and arachidonic acid, suggesting the complex mutual relationship of various factors/agonists influencing the function of platelets.

Coming safely to a stop: a review of platelet activity after cessation of antiplatelet drugs

The platelet P2Y12 antagonists are widely used, usually in combination with aspirin, to prevent atherothrombotic events in patients with acute coronary syndromes during percutaneous coronary intervention and after placement of arterial stents. Inhibition by clopidogrel or prasugrel lasts for the lifetime of the affected platelets and platelet haemostatic function gradually recovers after stopping the drug, as new unaffected platelets are formed. The optimal durations for dual antiplatelet therapy are prescribed by clinical guidelines. Continuation beyond the recommended duration is associated with an increased mortality, mainly associated with major bleeding. Fear of a 'rebound' of prothrombotic platelet activity on stopping the drug has provoked much discussion and many studies. However, review of the available literature reveals no evidence for production of hyper-reactive platelets after cessation of clopidogrel in patients who are stable. Any increase in acute coronary and other vascular events after stopping seems most likely therefore to be due to premature discontinuation or disruption of treatment while thrombotic risk is still high. No difference in rebound was found with the newer P2Y12 inhibitors, although ticagrelor and prasugrel are more potent platelet inhibitors than clopidogrel. Recent randomized controlled trials confirm it is safe to stop the thienopyridine and continue with aspirin alone in most patients after the duration of treatment recommended by the guidelines. Decisions on when to stop therapy in individuals, however, remain challenging and there is a growing rationale for platelet testing to assist clinical judgement in certain situations such as patients stopping dual antiplatelet therapy before surgery or in individuals at highest bleeding or thrombotic risk.

Men with lower HDL cholesterol levels have significant increment of soluble CD40 ligand and high-sensitivity CRP levels following the cessation of long-term clopidogrel therapy

AIM

The aim of this study was to examine whether the termination of long-term clopidogrel therapy results in a proinflammatory state and whether lipid parameters influence the inflammatory response after stopping the drug.

METHODS

A prospective, multicenter study was conducted among 200 patients with implanted coronary stents who received dual antiplatelet therapy for one year, without ischemic or bleeding events. According to the guidelines, clopidogrel was discontinued after one year. In all patients, the high-sensitivity C-reactive protein (hsCRP), soluble CD40 ligand (sCD40L) and lipid [total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C)] levels were measured twice: on the day of cessation of clopidogrel and 45 days after the termination of clopidogrel treatment.

RESULTS

In men (n=151), the sCD40L serum levels were significantly higher 45 days after the discontinuation of clopidogrel (p=0.007), while the hsCRP levels were not significantly different (p=0.407). Furthermore, when analyzed across the HDL-C quartiles, the hsCRP and sCD40L values were found to be associated with the levels of HDL-C after the discontinuation of clopidogrel in men. In addition, the men in the first HDL-C quartile exhibited the most pronounced increase in the sCD40L levels (p=0.001) and had significantly higher hsCRP levels (p=0.001) compared to the subjects in the other quartiles. Other lipid parameters did not show any associations with the sCD40L or hsCRP levels.

CONCLUSIONS

The discontinuation of clopidogrel is associated with higher increments in the sCD40L level, and a pronounced proinflammatory response is associated with a lower HDL-C concentration.

Evidence of platelet sensitization to ADP following discontinuation of clopidogrel therapy in patients with stable coronary artery disease

Epidemiological studies have linked clopidogrel discontinuation with an increased incidence of ischemic events. This has led to the hypothesis that clopidogrel discontinuation may result in a pharmacological rebound. We evaluated the impact of clopidogrel discontinuation on platelet function. Platelet aggregation was measured by light transmission aggregometry (LTA) in response to adenosine diphosphate (ADP) 0.5, 1, 1.5, 2.5, 5 and 10 µM and by VerifyNow® P2Y12, in 37 clinically stable coronary artery disease (CAD) patients scheduled to discontinue clopidogrel treatment, and 37 clinically stable CAD patients not taking clopidogrel. Platelet function was assessed the day before clopidogrel cessation and 1, 3, 7, 14, 21 and 28 days after. Clopidogrel had been initiated a median of 555 days (ranging from 200 to 2280 days) before the treating cardiologist recommended its discontinuation. All participants were taking aspirin, most commonly 80 mg daily although a minority was prescribed 325 mg daily. Following clopidogrel discontinuation, VerifyNow® P2Y12 did not detect any rebound platelet activity, but ADP-induced LTA showed platelet sensitization to ADP, particularly at low ADP levels. Increased platelet activity was detectable seven days after clopidogrel cessation and remained higher than in controls 28 days after discontinuation. No clinical event occurred in any of the participants during the 28 days following clopidogrel cessation. In conclusion, platelet sensitization to ADP as a consequence of chronic clopidogrel administration may partially explain the recrudescence of ischemic events following clopidogrel discontinuation in otherwise stable coronary artery patients.