Effects of cilostazol on platelet activation in coronary stenting patients who already treated with aspirin and clopidogrel

Cilostazol combined with P2Y12 receptor inhibitors: A substitute antiplatelet regimen for aspirin-intolerant patients undergoing percutaneous coronary stent implantation

Background

Cilostazol combined with P2Y₁₂ receptor inhibitor has been used as a substitute regimen for aspirin‐intolerant patients undergoing percutaneous coronary stent implantation on a small scale. Its exact impact on platelet functions and clinical benefits of aspirin‐intolerant patients is unknown.

Hypothesis

Cilostazol combined with P2Y₁₂ receptor inhibitors could be used as a substitute antiplatelet regimen for aspirin‐intolerant patients undergoing percutaneous coronary stent implantation.

Methods

In this multicenter prospective cohort trial, patients undergoing elective percutaneous coronary stent implantation were assigned to the cilostazol group (cilostazol plus P2Y₁₂ receptor inhibitors), based on aspirin intolerance criteria, or the aspirin group (aspirin plus P2Y₁₂ receptor inhibitors). Platelet PAC‐1, CD62p, and vasodilator‐stimulated phosphoprotein phosphorylation (VASP‐P) were detected by flow cytometry. The primary endpoints were major adverse cardiovascular and cerebrovascular events (MACCE) including all‐cause death, acute myocardial infarction, emerging arrhythmia, nonfatal stroke, and heart failure. The secondary endpoints were the Bleeding Academic Research Consortium (BARC) bleeding events.

Results

One hundred and fifty‐four aspirin‐intolerant percutaneous coronary stent implantation patients and 154 matched aspirin‐tolerant patients from a total of 2059 percutaneous coronary stent implantation patients were enrolled. The relative activation level of PAC‐1, CD62p, and platelet reaction index reflected by the VASP‐P test were similar in the two groups (p > .05). After 12 months of follow‐up, the incidence of all‐cause death was 1.9% in the cilostazol group and 1.3% in the aspirin group (risk ratio [RR], 1.500; 95% confidence interval [CI], 0.254–8.852; p = 1.000); the incidence of acute myocardial infarction was 0.6% in the cilostazol group and 1.3% in the aspirin group (RR, 0.500; 95% CI, 0.046–5.457; p = 1.000). No significant difference was seen in other MACCE events, or in any types of BARC bleeding events.

Conclusions

Cilostazol combined with P2Y₁₂ inhibitors was not inferior to aspirin‐based standard therapy and could be used as a reasonable substitute antiplatelet regimen for aspirin‐intolerant patients undergoing percutaneous coronary stent implantation, but again with limitations, which required a larger sample and longer follow‐up to confirm its efficacy.

Update on Cilostazol: A Critical Review of Its Antithrombotic and Cardiovascular Actions and Its Clinical Applications

Cilostazol, a phosphodiesterase III inhibitor, has vasodilating and antiplatelet properties with a low rate of bleeding complications. It has been used over the past 25 years for improving intermittent claudication in patients with peripheral artery disease (PAD). Cilostazol also has demonstrated efficacy in patients undergoing percutaneous revascularization procedures for both PAD and coronary artery disease. In addition to its antithrombotic and vasodilating actions, cilostazol also inhibits vascular smooth muscle cell proliferation via phosphodiesterase III inhibition, thus mitigating restenosis. Accumulated evidence has shown that cilostazol, due to its "pleiotropic" effects, is a useful, albeit underutilized, agent for both coronary artery disease and PAD. It is also potentially useful after ischemic stroke and is an alternative in those who are allergic or intolerant to classical antithrombotic agents (eg, aspirin or clopidogrel). These issues are herein reviewed together with the pharmacology and pharmacodynamics of cilostazol. Large studies and meta-analyses are presented and evaluated. Current guidelines are also discussed, and the spectrum of cilostazol's actions and therapeutic applications are illustrated.

Randomized comparison of new dual-antiplatelet therapy (aspirin, prasugrel) and triple-antiplatelet therapy (aspirin, clopidogrel, cilostazol) using P2Y12 point-of-care assay in patients with STEMI undergoing primary PCI

BACKGROUND

Both new dual antiplatelet therapy (DAT; aspirin and prasugrel) and triple antiplatelet therapy (TAT; aspirin, clopidogrel and cilostazol) are more potent than classic DAT (aspirin and clopidogrel). We compared the antiplatelet efficacy between new DAT and TAT in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary coronary percutaneous coronary intervention (PCI).

METHODS

Forty patients who were eligible for primary PCI were prospectively randomized to DAT group (n=20) or TAT group (n=20) immediately after hospital arrival. The primary end point was P2Y12 reaction unit (PRU) determined with the VerifyNow P2Y12 point-of-care assay at the time of discharge.

RESULTS

PRU value at discharge was significantly lower in patients receiving DAT compared with that of TAT (84.5 ± 44.7 vs. 128.4 ± 74.9, p=0.032). Percent platelet inhibition was significantly higher for DAT compared with TAT at discharge (72.1 ± 12.2 vs. 57.5 ± 23.5, p=0.020). Inter-patient variability of PRU values at discharge was significantly smaller in patient taking DAT compared with TAT (p=0.026).

CONCLUSION

A new DAT is more potent antiplatelet therapy than TAT in patients with STEMI undergoing primary PCI.

Detection of clopidogrel hyporesponsiveness using a point-of-care assay and the impact of additional cilostazol administration after coronary stent implantation in diabetic patients

BACKGROUND/AIMS

Impaired responsiveness to clopidogrel is common in patients with type 2 diabetes mellitus (DM). The aim of this study was to evaluate the clinical application of a point-of-care assay to detect impaired responsiveness to clopidogrel after coronary stent implantation in patients with type 2 DM.

METHODS

We measured P2Y12 reaction units (PRU) with the VerifyNow point-of-care assay in 544 consecutive patients undergoing dual or triple (i.e., dual plus cilostazol) anti-platelet therapy after coronary stent implantation. High platelet reactivity (HPR) was defined as a PRU value ≥ 240.

RESULTS

The mean PRU values were 233.5 ± 83.2 and 190.3 ± 85.5 in patients undergoing dual or triple anti-platelet therapy, respectively (p < 0.001). Patients with DM manifested higher post treatment PRU values (238.3 ± 82.4 vs. 210.8 ± 86.8, p = 0.001) and a higher frequency of HPR (44.8% vs. 31.0%, p = 0.003) as compared to patients without DM. We also found that higher PRU values and a higher frequency of HPR were present in patients with DM who were undergoing both triple and dual anti-platelet therapy. However, the higher post-treatment PRU values observed in patients with DM decreased with triple anti-platelet therapy (219.4 ± 82.5 vs. 247.9 ± 81.1, p = 0.044).

CONCLUSIONS

A point-of-care assay can detect elevated platelet reactivity and impaired responsiveness to clopidogrel in patients with type 2 DM. The addition of cilostazol to dual anti-platelet therapy may decrease post-treatment PRU values in patients with type 2 DM.

Comparison of triple anti-platelet therapy (aspirin, clopidogrel, and cilostazol) and double anti-platelet therapy (aspirin and clopidogrel) on platelet aggregation in type 2 diabetic patients undergoing drug-eluting stent implantation

BACKGROUND AND OBJECTIVES

Triple anti-platelet therapy may produce more potent inhibition of platelet aggregation in patients undergoing coronary stent implantation. We tested whether this effect could be maintained in diabetic patients, where platelet reactivity is increased and the risk of stent thrombosis is higher.

SUBJECTS AND METHODS

Fifty five type 2 diabetic patients who had undergone drug-eluting stent (DES) implantation and chronic anti-platelet therapy (>1 month) were stratified according to the status of anti-platelet therapy. Platelet aggregation after adenosine diphosphate (ADP; 10 micromol/L and 20 micromol/L) stimulation was compared using light transmittance aggregometry between dual (aspirin plus clopidogrel, n=34) and triple therapy (aspirin, clopidogrel plus cilostazol, n=21) groups.

RESULTS

The 2 groups had similar clinical and procedural characteristics. Maximal ADP-induced platelet aggregation was significantly lower in the triple therapy group than the dual therapy group (ADP 10 micromol/L, 37.1+/-15.4 vs. 28.3+/-11.8, p=0.03; ADP 20 micromol/L, 63.1+/-15.0 vs. 49.1+/-15.1, p=0.01), but there were no differences in diabetic treatment (oral hypoglycemic agent vs. insulin) or diabetic control {hemoglobin Alc (HbA1c) </=7 vs. HbA1c >7}.

CONCLUSION

Triple anti-platelet therapy showed more potent inhibition of maximal ADP induced platelet aggregation in type 2 diabetic patients receiving chronic anti-platelet therapy. This finding suggests that triple antiplatelet therapy may be more effective in preventing thrombotic complications after DES implantation in type 2 diabetic patients.

Efficacy of triple anti-platelet therapy including cilostazol in acute myocardial infarction patients undergoing drug-eluting stent implantation

BACKGROUND AND OBJECTIVES

Triple anti-platelet therapy is known to prevent restenosis after drug-eluting stent (DES) implantation. However, there is little available data concerning the efficacy of triple anti-platelet therapy for acute myocardial infarction (AMI).

SUBJECTS AND METHODS

We analyzed 528 consecutive patients with AMI undergoing DES implantation between Nov 2005 and Apr 2008. We compared clinical outcomes in the triple anti-platelet therapy (group I, n=413: cilostazol combined with aspirin and clopidogrel for at least one month) and dual antiplatelet therapy groups (group II, n=115: aspirin and clopidogrel).

RESULTS

There were no significant differences in baseline characteristics. However, ST elevation myocardial infarction (STEMI) and use of TAXUS(R) stents were more common (70.9% vs. 55.7%, p=0.002; 83.5% vs. 73.0%, p=0.011) in Group I. Group I had lower incidences of cardiac death, 6-month target lesion revascularization (TLR), and major adverse cardiac and cerebrovascular events (MACCE) compared to Group II (1.7% vs. 5.7%, p=0.022; 5.7% vs. 11.5%, 0.035; 7.9% vs. 16.0%, p=0.011). On subgroup analysis, the incidence of 6-month TLR was lower among patients with American College of Cardiology/American Heart Association (ACC/AHA) B2 or C lesions and non-STEMI (6.0% vs. 14.9%, p=0.012; 4.3% vs. 19.1%, p=0.002) in Group I compared to those in Group II. The rates of bleeding complications were no different between the two groups. On multivariate analysis, Killip III or IV and triple anti-platelet therapy were independent predictors of 6-month MACCE {hazard ratio (HR)=3.382; 95% confidence interval (CI)=1.384-8.262, HR=0.436; 95% CI=0.203-0.933}.

CONCLUSION

Triple anti-platelet therapy is safe and efficacious, and it prevents TLR in patients with AMI, especially those with complex lesions and non-STEMIs.

The clopidogrel resistance can be attenuated with triple antiplatelet therapy in patients undergoing drug-eluting stents implantation

BACKGROUND

Triple antiplatelet therapy may have a beneficial effect on prevention of thrombotic complication in patients undergoing coronary stenting. We investigated the prevalence of aspirin and clopidogrel resistance in patients treated with dual and triple antiplatelet regimen after percutaneous coronary intervention (PCI) with drug-eluting stents (DES).

METHODS

A total of 400 consecutive patients underwent successful PCI with DES were randomly assigned to therapy with dual antiplatelet regimens (aspirin plus clopidogrel, Group I, n = 200) and triple antiplatelet regimens (aspirin plus clopidogrel plus cilostazol, Group II, n = 200) At two weeks after PCI, aspirin and clopidogrel resistance were assayed in 379 patients (Group I, n = 186; Group II, n = 193) by using the VerifyNow System.

RESULTS

In Group I, 21 (11.3%) patients had aspirin resistance and 74 (40.0%) had clopidogrel resistance. In Group II, 19 (9.8%) were resistant to aspirin and 38 (19.7%) to clopidogrel. The aspirin reaction unit (ARU) was not significantly different between groups (448+/-67 vs. 439+/-64, P = 0.200), but the percent inhibition of clopidogrel was higher in Group II (41.4+/-24.3%,) comparing with that of Group I (26.5+/-18.7%, P < 0.001).

CONCLUSION

With triple antiplatelet therapy, the prevalence of clopidogrel resistance can be attenuated in patients undergoing PCI with DES.

Optimal management of platelet function after coronary stenting

Coronary stenting elicits vessel wall damage, and subsequent activation of platelets is implicated as a major component of complications such as acute, subacute, and late stent thrombosis. As such, dual antiplatelet therapy using aspirin and clopidogrel has become a routine adjunct to coronary stenting. Use of aspirin and clopidogrel with or without glycoprotein IIb/IIIa inhibitors after coronary stenting reduces the complication rate and improves long-term outcomes. Dual antiplatelet therapy using aspirin and clopidogrel is recommended for at least 4 weeks with bare metal stents, and for 3 to 6 months with drug-eluting stents for prevention of major adverse cardiac events. After coronary stenting, 1 year of dual antiplatelet therapy is recommended for prevention of future cardiac events. However, despite the use of antiplatelet agents, stent thrombosis occurs in approximately 1% of patients, with an increased likelihood of occurrence in high-risk patients or a lesion subset of patients. Although the incidence of stent thrombosis is low, stent thrombosis usually presents as acute coronary syndrome and the mortality rate is up to 45%. Thus, considering the widespread use of stents, a considerable number of people are inadequately protected from thrombotic events despite current standard antiplatelet therapy using aspirin and clopidogrel. A concern with clopidogrel is the loading time and loading dose required to achieve and maintain optimal inhibition of platelet aggregation. The current recommendation for ensuring maximum antiplatelet activity is administration of a 300-mg loading dose of clopidogrel initiated at least 6 hours prior to percutaneous coronary intervention (PCI), and ideally the day before. If this is not possible, a loading dose of 600 mg of clopidogrel should be administered at least 2 hours before PCI. Recently, new combinations of antiplatelet agents (ie, triple therapy using aspirin, clopidogrel, and cilostazol) and new drugs with potent antiplatelet effects (ie, Prasugrel , Cangrelor , and AZD6140) have been evaluated in clinical trials; such treatments may help reduce the number of cardiac events after coronary stenting.

Cilostazol could ameliorate platelet responsiveness to clopidogrel in patients undergoing primary percutaneous coronary intervention

BACKGROUND

Cilostazol increases the cyclic adenosine monophosphate levels in platelets and might ameliorate the antiplatelet activity of clopidogrel. This study investigated the additional effect of cilostazol on platelet aggregation measured by a VerifyNow analyzer and soluble CD40 ligand (sCD40L) as a marker of activated platelet in patients undergoing primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

Sixty cases of primary PCI were randomly assigned to dual (aspirin and clopidogrel) or triple (dual plus cilostazol) therapy. The antiplatelet effects of aspirin and clopidogrel were evaluated by VerifyNow tests. The plasma sCD40L levels at admission, 24 h and 21 days were measured by the ELISA method. The arachidonic acid induced platelet aggregation was similar in both groups. However, the triple group had a significantly lower P2Y12 reaction unit (dual 208.8+/-69.0 vs triple 168.2+/-79.2, p=0.041) and higher % inhibition of adenosine diphosphate (ADP)-induced platelet aggregation (dual 23.8+/-21.4% vs triple 40.5+/-21.0%, p=0.004). In the multivariate analysis, cilostazol was a negative predictor for low responders to clopidogrel (95% confidence interval 0.067-0.711). The plasma sCD40L levels were not significantly different between the 2 groups at the same point of time.

CONCLUSIONS

The addition of cilostazol to the combination of aspirin plus clopidogrel significantly increases the inhibition of ADP-induced platelet aggregation. However, there was no additive effect on aspirin-induced antiplatelet activity or lowering of sCD40L.

Effects of triple antiplatelet therapy (aspirin, clopidogrel, and cilostazol) on platelet aggregation and P-selectin expression in patients undergoing coronary artery stent implantation

The purpose of this study was to determine the effect of the addition of cilostazol to aspirin plus clopidogrel on platelet aggregation after intracoronary stent implantation. Twenty patients who underwent coronary stent placement were randomly assigned to therapy with aspirin plus clopidogrel (dual-therapy group, n = 10) or aspirin plus clopidogrel plus cilostazol (triple-therapy group, n = 10). A loading dose of clopidogrel (300 mg) and cilostazol (200 mg) was administered immediately after stent placement, and clopidogrel (75 mg/day) and cilostazol (100 mg twice daily) were given for 1 month. Platelet aggregation in response to adenosine diphosphate (ADP; 5 and 20 micromol/L) or collagen and P-selectin (CD-62P) expression was assayed at baseline, 2 hours, 24 hours, 1 week, and 1 month after stent placement. Inhibition of ADP-induced platelet aggregation was significantly higher in patients receiving triple therapy than those receiving dual therapy from 24 hours after stent placement, and inhibition of collagen-induced platelet aggregation was significantly higher in the triple-therapy group beginning 1 week after stent placement. P-Selectin expression was significantly lower in the triple-therapy than dual-therapy group at 1 week and 30 days. In conclusion, compared with dual antiplatelet therapy, triple therapy after coronary stent placement resulted in more potent inhibition of platelet aggregation induced by ADP and collagen. These findings suggest that triple therapy may be used clinically to prevent thrombotic complications after coronary stent placement.

Cilostazol, a phosphodiesterase 3 inhibitor, protects mice against acute and late ischemic brain injuries

Cilostazol, a selective inhibitor of phosphodiesterase 3, exerts neuroprotective effects on acute brain injury after cerebral ischemia in rats. However, it is unknown whether cilostazol affects the subacute or chronic ischemic injury. In the present study, we evaluated the dose- and time-dependent effects of cilostazol on acute ischemic brain injury and the long-lasting effect on the late (subacute/chronic) injury in mice with focal cerebral ischemia induced by transient middle cerebral artery occlusion. We found that pre-treatment of cilostazol (injected i.p. at 30 min before ischemia) significantly ameliorated the acute injury 24 h after ischemia, and the effective doses were 3-10 mg/kg. The post-treatment of cilostazol (10 mg/kg) was effective on the acute injury when it was injected 1 and 2 h after ischemia. In addition, for the late injury, post-treatment of cilostazol (10 mg/kg, i.p., for 7 consecutive days after ischemia) attenuated neurological dysfunctions, brain atrophy and infarct volume. It also inhibited astrocyte proliferation/glial scar formation and accelerated the angiogenesis in the ischemic boundary zone 7 and 28 days after ischemia. Thus, we conclude that cilostazol protects against not only the acute injury, but also the late injury in mice with focal cerebral ischemia; especially it can modify brain remodeling, astrogliosis and angiogenesis.

Triple Versus Dual Antiplatelet Therapy After Coronary Stenting

OBJECTIVES

We evaluated safety and efficacy of triple antiplatelet therapy with aspirin, clopidogrel, or ticlopidine and cilostazol after coronary stenting.

BACKGROUND

Triple antiplatelet therapy might have beneficial effect to prevent thrombotic complications in patients undergoing coronary stenting.

METHODS

Patients undergoing successful coronary stenting were divided into dual antiplatelet therapy (aspirin plus clopidogrel or ticlopidine, group I, n = 1,597) and triple antiplatelet therapy (aspirin plus clopidogrel or ticlopidine plus cilostazol, group II, n = 1,415) groups. The primary end point included death, myocardial infarction, target lesion revascularization, or stent thrombosis within 30 days. The secondary end point was side effects of study drugs, including major bleeding, vascular complication, hepatic dysfunction, and hematological complications.

RESULTS

Multi-vessel stenting and the use of long stents were more prevalent in group II than in group I. The primary end point was 0.8% in group I and 0.3% in group II (p = 0.085). Stent thrombosis within 30 days was significantly lower in group II (n = 1, 0.1%) than in group I (n = 9, 0.5%; p = 0.024). The independent predictors of stent thrombosis were primary stenting (odds ratio [OR] 7.9, 95% confidence interval [CI] 2.0 to 30.8, p = 0.003) and triple therapy (OR 0.12, 95% CI 0.015 to 0.98, p = 0.048). The overall adverse drug effects, including major bleeding, neutropenia, and thrombocytopenia, were no different between two groups (1.8% vs. 2.6%, p = 0.104).

CONCLUSIONS

Compared with the dual antiplatelet regimen, triple antiplatelet therapy seemed to be more effective in preventing thrombotic complications after stenting without an increased risk of side effects. Triple antiplatelet therapy might be safely applied in patients or lesions with a high risk of stent thrombosis.