The Increased Ischemic Risk During the Early Period After Clopidogrel Noncompliance in Patients with Acute Coronary Syndrome: A Meta-Analysis

Although dual antiplatelet therapy for secondary prevention in acute coronary syndrome (ACS) is highly recommended by current guidelines, P2Y12 inhibitor non-adherence often occurs and devastates prognosis. To evaluate whether the ischemic risk during the early period of clopidogrel noncompliance was increased among ACS patients, a comprehensive search of PubMed, Embase, and Web of Science was conducted to identify studies reporting early ischemic risk after clopidogrel noncompliance in ACS patients. The primary endpoint was a composite of death or myocardial infarction (MI). Effect sizes were synthesized in patients with or without revascularization. A total of 7 observational studies focusing on clopidogrel noncompliance were included in this meta-analysis, whereas no studies involving ticagrelor or prasugrel were retrieved. A significantly increased risk of death or MI 0 to 90 days after clopidogrel noncompliance was found compared with that during 90 to 180 or 90 to 360 days regardless of revascularization (incidence rate ratio [IRR]: 2.01, 95% confidence interval (CI): 1.62-2.49, P < .001, I2 = 9%) or not (IRR: 1.61, 95% CI: 1.05-2.48, P < .001, I2 = 74%). Patients undergoing percutaneous coronary intervention had a higher risk of death or MI 0 to 90 days after clopidogrel noncompliance compared with 90-180 or 90-360 days irrespective of drug-eluting stent or bare metal stent implantation (P < .05 for both). The early ischemic risk after clopidogrel noncompliance is significantly higher than the late risk in ACS patients. Antiplatelet noncompliance remains a serious concern.

Adherence and persistence analysis in patients treated with double antiplatelet therapy (DAPT) at two years in real life

INTRODUCTION

Double antiplatelet therapy (DAPT) is indicated for the treatment of coronary artery diseases (CAD). The optimal duration of therapy with DAPT continues to be a subject of debate in the scientific community. To improve adherence to DAPT, the FDC (fixed dose combination) of Acetylsalicylic acid (ASA) and clopidogrel was developed into a single pill instead of two separate pills thus facilitating the dosage and administration of the therapy and increasing compliance. The aim of this study was to assess adherence and persistence over a period of two years in patients treated with DAPT composed of: ASA/clopidogrel, ASA/prasugrel, ASA/ticagrelor and FDC with ASA and clopidogrel in real life and to assess whether the use of ASA and clopidogrel FDC is associated with improved adherence.

MATERIALS AND METHODS

In the following retrospective pharmacological-observational non-interventional study, all patients treated with DAPT in the Hospital of Pescara from January 2010 to October 2019 were considered. Persistence to treatment is defined as the duration of time from initiation to discontinuation of treatment. Adherence was calculated as the ratio between Received Daily Dose (RDD) and Prescribed Daily Dose (PDD).

RESULTS

277 patients treated with ASA/clopidogrel, 77 patients treated with ASA/prasugrel, 57 patients treated with ASA/ticagrelor and 108 patients treated with FDC of ASA/clopidogrel were analysed. Persistence curves at two years showed a statistically significant difference (p < 0.001). Adherence to therapy was optimal with an absolute value at two years of 0.96. Adherence was better in patients treated with ASA/prasugrel with a value of 0.98 and with 97 % of patients with an adherence value greater than or equal to 0.8, while, it was worse in patients treated with FDC ASA/clopidogrel with an absolute value of 0.94 and with 88 % of patients with an optimal adherence value. No statistically significant difference was found between the ASA/clopidogrel FDC in comparison to each component taken as a separate pill (p = 0.0752).

CONCLUSION

DAPT along with ASA/clopidogrel showed a statistically significant better persistence than ASA/ticagrelor and ASA/prasugrel. Whereas, to our knowledge and as per the current literature no statistically significant differences were found, in terms of adherence in real life, between the use of ASA/Clopidogrel FDC and the use of two different pills.

Clopidogrel Use as Single Antiplatelet Therapy in Outpatients with Stable Coronary Artery Disease: Prevalence, Correlates and Association with Prognosis (from the CORONOR Study)

Background: Clopidogrel use as single antiplatelet therapy (SAPT) has never been evaluated in stable coronary artery disease (CAD) outpatients either as compared to placebo or aspirin. Methods: We therefore studied 2,823 outpatients included in a prospective registry. The patients were divided into 2 groups according to their antiplatelet therapy regimen: patients treated with clopidogrel were compared with those treated with aspirin alone. Results: The mean time since CAD diagnosis was 7.9 years. Altogether, 776 (27.5%) patients received clopidogrel as SAPT. Factors independently associated with clopidogrel use were prior aortic or peripheral intervention, drug-eluting stent implantation, stroke, carotid endarterectomy and time since CAD diagnosis. Clopidogrel tended to be used in higher-risk patients: composite of cardiovascular death, myocardial infarction or stroke at 5.8 versus 4.2% (p = 0.056). However, after propensity score matching, similar event rates were observed between the groups: 5.9% when treated with clopidogrel versus 4.4% with aspirin (p = 0.207). The rate of bleeding was also similar between the groups. Conclusions: Our study shows that a significant proportion of stable CAD patients are treated with clopidogrel as SAPT in modern practice. Several correlates of such an attitude were identified. Our results suggest that this strategy is not beneficial as compared to aspirin alone in terms of ischaemic or bleeding events.

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.

Dual antiplatelet therapy in patients with a long coronary artery lesion over 30 mm: Determinants and impact on prognosis

BACKGROUND

The ideal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) is under debate. Lesion length is a well-recognized predictor of PCI complexity and long-term outcome.

AIM

To evaluate the determinants and impact on outcome of long-term DAPT in a retrospective cohort of patients treated for a long coronary lesion.

METHODS

Patients (n=460) who underwent PCI for a long lesion (>30 mm) were divided into two groups according to antiplatelet regimen at 1 year: patients who stopped DAPT before 1 year (single antiplatelet therapy group; n=168) and patients who continued DAPT for longer than 1 year (n=292).

RESULTS

Mean lesion length was 35.7±7.1 mm. The proportion of patients who continued DAPT after 1 year was 63.5%. The main determinants of long-term DAPT were initial presentation as myocardial infarction and implantation of a drug-eluting stent. Median follow-up was 37.4 (23-51) months after the 1-year period following the index PCI. Long-term DAPT was highly associated with a lower risk of all-cause and cardiovascular mortality by multivariable analysis and after adjustment for other predictors: hazard ratios 0.11 (95% confidence interval 0.03-0.32) and 0.15 (95% confidence interval 0.04-0.62), respectively. No increase in major bleeding was noted.

CONCLUSION

In a contemporary practice, nearly two-thirds of patients who undergo PCI for a long lesion are treated with DAPT for several years. Our results suggest that long-term DAPT is beneficial in this subset of patients identified as being at high risk.

Dual antiplatelet therapy in patients with stable coronary artery disease in modern practice: prevalence, correlates, and impact on prognosis (from the Suivi d'une cohorte de patients COROnariens stables en region NORd-Pas-de-Calais study)

BACKGROUND

The prevalence and correlates of dual-antiplatelet therapy (DAPT) use in stable coronary artery disease (CAD) are unknown. In addition, whether prolonged DAPT may impact prognosis in stable CAD has not been studied in real-life conditions.

METHODS

We studied 3,691 patients included in a prospective registry on stable CAD. The patients were divided in 2 groups according to their antiplatelet therapy regimen at inclusion: patients treated with DAPT were compared with those treated with single-antiplatelet therapy (SAPT). The primary outcome was a composite of cardiovascular death, myocardial infarction, or stroke.

RESULTS

Altogether, 868 (24%) patients received DAPT. Factors positively associated with DAPT use were persistent angina at inclusion, body mass index, myocardial infarction since 1 to 3 years, myocardial revascularization since 1 to 3 years, multivessel CAD, prior drug-eluting stent implantation, and prior aortic or peripheral intervention. Factors negatively associated with DAPT use were age, prior coronary bypass, and left ventricular ejection fraction. The rate of the primary outcome at 2 years was similar whether patients were treated with SAPT (4.6%) or DAPT (5.5%) (P = .301). Similar rates were also observed after propensity score matching: 5.7% when treated with SAPT versus 5.5% when treated with DAPT (P = .886). The rate of bleeding was similar between groups.

CONCLUSIONS

Our study shows that a significant proportion of stable CAD patients are treated with DAPT in modern practice. Several correlates of DAPT were identified. Although no increase in bleeding was observed, our results do not support the prescription of prolonged DAPT.

A randomized controlled trial of platelet activity before and after cessation of clopidogrel therapy in patients with stable cardiovascular disease

OBJECTIVES

The aim of this randomized placebo-controlled trial was to determine if withdrawing clopidogrel therapy leads to increased platelet activity compared with pre-treatment values in patients with stable coronary artery or peripheral arterial disease.

BACKGROUND

Reports of increased cardiovascular events after planned cessation of clopidogrel therapy have raised concerns over the possible existence of a rebound in platelet activity.

METHODS

In all, 171 patients receiving established aspirin therapy were randomly assigned to placebo or clopidogrel (75 mg daily) for 28 days. Blood samples were taken at pre-treatment baseline, on treatment just before discontinuation of study drug, and on days 7, 14, and 28 after discontinuation. The primary outcome measure was adenosine diphosphate (ADP)-stimulated platelet fibrinogen binding. Six secondary outcomes were assessed: ADP-stimulated platelet P-selectin, unstimulated platelet fibrinogen binding, and light transmission aggregometry with ADP 5 and 10 μmol/l recorded at maximum and at 6 min.

RESULTS

The ADP-stimulated platelet fibrinogen binding, P-selectin expression, and platelet aggregation were lower on treatment with clopidogrel compared with baseline (p < 0.0001), but returned to baseline levels by 7 days after discontinuation. Mixed model analyses excluding the on-treatment timepoint showed no overall differences between the clopidogrel and placebo groups (p > 0.05). Furthermore, there was no evidence of an interaction between platelet inhibition over time and treatment allocation.

CONCLUSIONS

This trial found no evidence for rebound of platelet activity to above baseline after stopping clopidogrel in patients with stable coronary artery disease or peripheral arterial disease. (Is Cessation of Clopidogrel Therapy Associated With Rebound of Platelet Activity in Stable Vascular Disease Patients?; ISRCTN77887299/77887299).

Circadian variation of stent thrombosis and the effect of more robust platelet inhibition: a post hoc analysis of the TRITON-TIMI 38 trial

BACKGROUND

The well-described morning peak in the onset of acute coronary syndromes has been partly attributed to increased platelet activity upon arising. It has been suggested that stent thrombosis (ST) exhibits a similar pattern. We assessed whether a diurnal variation in ST occurs, and whether more robust antiplatelet therapy with prasugrel (vs clopidogrel) can attenuate a morning excess.

METHODS AND MATERIALS

Patients from the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis in Myocardial Infarction (TRITON-TIMI) 38 trial (N = 13 608) with adjudicated ST classified per the Academic Research Consortium definitions of definite (N = 135) and probable (N = 27) were grouped into prespecified 8-hour intervals by time of onset: early (6 am-2 pm), late-day (2 pm-10 pm), and overnight (10 pm-6 am). We compared the rates per 1000 patients of ST across time intervals and stratified by treatment and stent type.

RESULTS

A diurnal variation in definite/probable ST was observed with rates of 6.5, 3.7, and 2.1 for early, late-day, and overnight intervals, respectively (P < .001), per 1000 patients treated. A sensitivity analysis excluding periprocedural acute-ST (<24 hours after index percutaneous coronary intervention [PCI]) resulted in similar findings (5.2, 2.5, and 1.8 per 1000, P < .001). The circadian variation in ST was observed in patients on clopidogrel (9.7, 4.8, and 3.1 per 1000, P < .001) with the highest rate of ST early in the day. Patients on prasugrel also demonstrated a circadian variation with particularly low rates of overnight ST (3.4, 3.0, and 1.1 per 1000, P = .020).

CONCLUSIONS

In TRITON-TIMI 38 trial, the timing of ST exhibited a significant diurnal variation similar to that seen with onset of other acute coronary syndromes. ST occurred less frequently among patients randomized to prasugrel compared to clopidogrel with the greatest absolute reduction (6.2 per 1000 patients) in events earlier in the day when platelet activity is known to be highest.

Adherence and persistence with prasugrel following acute coronary syndrome with percutaneous coronary intervention

PURPOSE

To measure the adherence and persistence of patients with acute coronary syndrome (ACS) initiating prasugrel after percutaneous coronary intervention (PCI).

METHODS

Using the Thomson Reuters MarketScan Commercial and Medicare Supplemental database, a retrospective cohort study identified patients initiating prasugrel following ACS-PCI hospitalization in 2009-2011. Prasugrel adherence over 12 months was measured using the medication possession ratio (MPR); predictors of adherence were identified using a logistic regression model. Persistence was defined as time on continuous therapy; a Cox model identified predictors of prasugrel discontinuation.

RESULTS

Among 1,340 patients, the mean age was 57 years; 79.5 % were male. Median prasugrel MPR was 93.2 %; 69.0 % of patients had an MPR ≥80 %. Predictors of adherence <80 % included prior PCI [odds ratio (OR) 0.60; 95 % confidence interval (CI) 0.40-0.90], prior depression (OR 0.37; 95 % CI 0.16-0.84), prior bleeding (OR 0.41; 95 % CI 0.19-0.86), and baseline anticoagulant use (OR 0.13; 95 % CI 0.03-0.55). Baseline statin use predicted higher adherence (OR 1.56; 95 % CI 1.21-2.02). The median duration of prasugrel therapy was 259 days. Predictors of discontinuation included prior anemia [hazard ratio (HR) 1.63; 95 % CI 1.21-2.21], prior cardiomyopathy (HR 2.72; 95 % CI 1.44-5.13), and prior ischemic heart disease (HR 1.15; 95 % CI 1.00-1.32); baseline statin use predicted reduced risk of discontinuation (HR 0.85; 95 % CI 0.75-0.97).

CONCLUSIONS

Although adherence to prasugrel was generally high, the duration of therapy was frequently below recommendations. An awareness of risk factors for low adherence or early discontinuation can point to appropriate targets for intervention.

Combination of cilostazol and clopidogrel attenuates rat critical limb ischemia

BACKGROUND AND AIM

Procedural failure and untoward clinical outcomes after surgery remain problematic in critical limb ischemia (CLI) patients. This study tested a clopidogrel-cilostazol combination treatment compared with either treatment alone in attenuating CLI and improving CLI-region blood flow in rats.

METHODS

Male Sprague-Dawley rats (n = 40) were equally divided into five groups: control, CLI induction only, CL I + cilostazol (12.0 mg/day/kg), CLI + clopidogrel (8.0 mg/kg/day) and CLI + combined cilostazol-clopidogrel. After treatment for 21 days, Laser Doppler imaging was performed.

RESULTS

On day 21, the untreated CLI group had the lowest ratio of ischemic/normal blood flow (p < 0.001). Inflammation measured by VCAM-1 protein expression; oxidative stress; PAI-1, MMP-9 and TNF-α mRNA expressions; and immunofluorescence staining (IF) of CD68+ cells was lower with combined treatment than with the other treatments, and lower in the two single-treatment groups than the untreated CLI group (all p < 0.01). Anti-inflammatory mRNA expression of interleukin-10, and eNOS showed a reverse pattern among these groups. Apoptosis measured by Bax, caspase-3 and PARP; and muscle damage measured by cytosolic cytochrome-C, and serum and muscle micro-RNA-206 were all lowest with combination treatment, and the two single-treatment groups showed lower values than the untreated group (all p < 0.001). Angiogenesis measured by eNOS, IF staining of CD31+ and vWF + cells; and number of vessels in CLI region were highest with combination treatment and higher in the single-treatment groups than the untreated group (all p < 0.001).

CONCLUSION

Combined cilostazol-clopidogrel therapy is superior to either agent alone in improving ischemia in rodent CLI.

Rate of nuisance bleedings and impact on compliance to prasugrel in acute coronary syndromes

Antiplatelet agents are critical to prevent thrombotic events in patients with acute coronary syndromes, particularly those who undergo percutaneous coronary intervention. Prasugrel is a potent P2Y(12)-adenosine diphosphate receptor antagonist that is superior to clopidogrel in such patients. Previous studies have observed that nuisance and internal bleedings were relatively frequent in patients under clopidogrel therapy and were associated with noncompliance. Furthermore, premature drug discontinuation is associated with thrombotic recurrences. The aim of the present study was to investigate the rate of nuisance or internal bleedings in patients receiving prasugrel and its relation with compliance. This prospective multicenter study included 396 patients. Bleeding events were recorded and classified as alarming, nuisance, or internal according. Compliance with prasugrel therapy was assessed. Almost half of the patients (48.5%) were included for ST-segment elevation acute coronary syndromes. During the 1-month follow-up period, 54 patients (13.6%) had bleeding events. Most bleeding events were classified as internal or nuisance (96%). Internal and nuisance bleedings were associated with high rates of prasugrel discontinuation (16.6% and 14.7%, respectively). Nuisance and internal bleedings were significantly associated with prasugrel discontinuation in multivariate analysis (odds ratio 3.1, 95% confidence interval 1.01 to 9.2, p = 0.04). The rate of major adverse cardiovascular events was 2.3%. No relation was observed between minor bleeds, compliance, and major adverse cardiovascular events. In conclusion, in the present study, minor bleedings were common during the first month after percutaneous coronary intervention and were significantly associated with prasugrel withdrawal.

Duration of dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stent implantation: a review of the current guidelines and literature

Dual antiplatelet therapy is the mainstay of medical treatment after percutaneous coronary intervention regarding the risk of stent thrombosis occurrence. Since the beginning of the stenting era, antiplatelet regimens have evolved according to the emerging and widespread diffusion of new devices and more challenging indications for their use. In the past years, concerns have been raised about the safety of drug-eluting stent implantation with regard to late and very late stent thrombosis. Thus, the length of dual antiplatelet therapy has been progressively increased with marked individual and local differences. However, prolonged antiplatelet therapy leads to increased risk of bleeding, especially in the setting of surgical procedures, traumas, and/or other diseases. To date, the exact duration of dual antiplatelet therapy after drug-eluting stent implantation is still debated in the literature. The aim of this article is to review the literature and the current guidelines on the risks and benefits of pursuing dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stent implantation.