Comparison of 1-Year Outcomes of Triple (Aspirin + Clopidogrel + Cilostazol) Versus Dual Antiplatelet Therapy (Aspirin + Clopidogrel + Placebo) After Implantation of Second-Generation Drug-Eluting Stents into One or More Coronary Arteries: from the DECREASE-PCI Trial

The Role of Cilostazol, a Phosphodiesterase-3 Inhibitor, in the Development of Atherosclerosis and Vascular Biology: A Review with Meta-Analysis

Atherosclerotic cardiovascular disease (ASCVD) stands as the leading global cause of mortality. Addressing this vital and pervasive condition requires a multifaceted approach, in which antiplatelet intervention plays a pivotal role, together with antihypertensive, antidiabetic, and lipid-lowering therapies. Among the antiplatelet agents available currently, cilostazol, a phosphodiesterase-3 inhibitor, offers a spectrum of pharmacological effects. These encompass vasodilation, the impediment of platelet activation and aggregation, thrombosis inhibition, limb blood flow augmentation, lipid profile enhancement through triglyceride reduction and high-density lipoprotein cholesterol elevation, and the suppression of vascular smooth muscle cell proliferation. However, the role of cilostazol has not been clearly documented in many guidelines for ASCVD. We comprehensively reviewed the cardiovascular effects of cilostazol within randomized clinical trials that compared it to control or active agents and involved individuals with previous coronary artery disease or stroke, as well as those with no previous history of such conditions. Our approach demonstrated that the administration of cilostazol effectively reduced adverse cardiovascular events, although there was less evidence regarding its impact on myocardial infarction. Most studies have consistently reported its favorable effects in reducing intermittent claudication and enhancing ambulatory capacity in patients with peripheral arterial disease. Furthermore, cilostazol has shown promise in mitigating restenosis following coronary stent implantation in patients with acute coronary syndrome. While research from more diverse regions is still needed, our findings shed light on the broader implications of cilostazol in the context of atherosclerosis and vascular biology, particularly for individuals at high risk of ASCVD.

Cilostazol induces vasorelaxation through the activation of the eNOS/NO/cGMP pathway, prostanoids, AMPK, PKC, potassium channels, and calcium channels

OBJECTIVE

This study aimed to investigate vasoactive effect mechanisms of cilostazol in rat thoracic aorta.

MATERIALS AND METHODS

The vessel rings prepared from the thoracic aortas of the male rats were placed in the chambers of the isolated tissue bath system. The resting tone was adjusted to 1 g. Following the equilibration phase, potassium chloride or phenylephrine was used to contract the vessel rings. When achieving a steady contraction, cilostazol was applied cumulatively (10-8-10-4 M). In the presence of potassium channel blockers or signaling pathway inhibitors, the same experimental procedure was performed.

RESULTS

Cilostazol exhibited a significant vasorelaxant effect in a concentration-dependent manner (pD2: 5.94 ± 0.94) (p < .001). The vasorelaxant effect level of cilostazol was significantly reduced by the endothelial nitric oxide synthase inhibitor L-NAME (10-4 M), soluble guanylate cyclase inhibitor methylene blue (10 µM), cyclooxygenase 1/2 inhibitor indomethacin (5 µM), adenosine monophosphate-activated protein kinase inhibitor compound C (10 µM), non-selective potassium channel blocker tetraethylammonium chloride (10 mM), large-conductance calcium-activated potassium channel blocker iberiotoxin (20 nM), voltage-gated potassium channel blocker 4-Aminopyridine (1 mM), and inward-rectifier potassium channel blocker BaCl2 (30 µM) (p < .001). Moreover, incubation of cilostazol (10-4 M) significantly reduced caffeine (10 mM), cyclopiazonic acid (10 µM), and phorbol 12-myristate 13-acetate-induced (100 µM) vascular contractions (p < .001).

CONCLUSIONS

In the rat thoracic aorta, the vasodilator action level of cilostazol is quite noticeable. The vasorelaxant effects of cilostazol are mediated by the eNOS/NO/cGMP pathway, prostanoids, AMPK pathway, PKC, potassium channels, and calcium channels.

Efficacy and safety of cilostazol-based triple antiplatelet therapy compared with clopidogrel-based dual antiplatelet therapy in patients with acute ST-elevation myocardial infarction undergoing percutaneous coronary intervention: A multicenter, randomized, open-label, phase 4 trial

BACKGROUND

Previous studies reported that compared to conventional dual antiplatelet therapy (DAT; aspirin + clopidogrel), triple antiplatelet therapy (TAT), involving the addition of cilostazol to DAT, had better clinical outcomes in patients with ST-elevation myocardial infarction (STEMI). However, the optimal duration of TAT is yet to be determined.

METHODS

In total, 985 patients with STEMI who underwent primary percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) were prospectively enrolled in 15 PCI centers in South Korea and China. We randomly assigned patients into 3 groups: DAT (aspirin and clopidogrel for 12 months), TAT 1M (aspirin, clopidogrel, and cilostazol for 1 month), and TAT 6M (aspirin, clopidogrel, and cilostazol for 6 months). The primary endpoint was 1-year major adverse cardiovascular events (MACEs), defined as a composite of all-cause death, recurrent myocardial infarction, stroke, or repeat revascularization.

RESULTS

The primary endpoint did not differ among the 3 groups (8.8% in DAT, 11.0% in TAT 1M, and 11.6% in TAT 6M; hazard ratio for TAT 1M vs DAT, 1.302; 95% confidence interval [CI], 0.792-2.141; P = .297; hazard ratio for TAT 6M vs DAT, 1.358; 95% CI, 0.829-2.225; P = .225). With respect to in-hospital outcomes, more bleeding events occurred in the TAT group than in the DAT group (1.3% vs 4.7% vs 2.6%, P = .029), with no significant differences in major bleeding events. Additionally, the TAT group had a higher incidence of headaches (0% vs 1.6% vs 2.6%, P = .020).

CONCLUSIONS

The addition of cilostazol to DAT did not reduce the incidence of 1-year MACEs compared with DAT alone. Instead, it may be associated with an increased risk of drug intolerance and side effects, including in-hospital bleeding and headaches.

Monitoring antiplatelet therapy: where are we now?

Single antiplatelet therapy represents the cornerstone of thrombosis prevention in atherosclerotic cardiovascular disease. Dual antiplatelet therapy (DAPT), consisting of aspirin plus a P2Y12 inhibitor, is the standard of care for patients with acute coronary syndrome or undergoing both coronary and peripheral percutaneous interventions. Recent data suggest the efficacy of DAPT also after minor stroke. In this setting, a large body of evidence has documented that genetic and acquired patients' characteristics may affect the magnitude of platelet inhibition induced by antiplatelet agents. The implementation of tools allowing the identification and prediction of platelet inhibition has recently been shown to improve outcomes, leading to an optimal balance between antithrombotic efficacy and bleeding risk. We are therefore clearly moving towards tailored antiplatelet therapy. The aim of this paper is to summarize the available evidence on the evaluation of platelet inhibition in patients with coronary, peripheral, or cerebrovascular atherosclerosis. We will here focus on antiplatelet therapy based on both aspirin and P2Y12 inhibitors. In addition, we provide practical insights into the clinical settings in which it appears reasonable to implement antiplatelet therapy monitoring.

A Randomized Controlled Trial Evaluating Outcome Impact of Cilostazol in Patients with Coronary Artery Disease or at a High Risk of Cardiovascular Disease

Previous studies found that cilostazol has a favorable effect on glucose and lipid homeostasis, endothelial function, atherosclerosis, and vasculo-angiogenesis. However, it is poorly understood whether these effects can translate into better clinical outcomes. This study investigated the outcome effect of cilostazol in patients with coronary artery disease (CAD) or at a high risk of cardiovascular (CV) disease. We conducted a randomized, double-blind, placebo-controlled trial involving 266 patients who received cilostazol, 200 mg/day (n = 134) or placebo (n = 132). Pre-specified clinical endpoints including composite major adverse cardiovascular events (MACE) (CV death, non-fatal myocardial infarct, non-fatal stroke, hospitalization for heart failure, or unplanned coronary revascularization), the composite major coronary event (MCE) and major adverse CV and cerebrovascular event (MACCE), were prospectively assessed. The mean duration of follow-up was 2.9 years. Relative to placebo, cilostazol treatment had a borderline effect on risk reduction of MACE (hazard ratio [HR], 0.67; 95% confidence interval (CI), 0.34–1.33), whereas the beneficial effect in favor of cilostazol was significant in patients with diabetes mellitus or a history of percutaneous coronary intervention (p for interaction, 0.02 and 0.06, respectively). Use of cilostazol, significantly reduced the risk of MCE (HR, 0.38; 95% CI, 0.17–0.86) and MACCE (HR, 0.47; 95% CI, 0.23–0.96). A significantly lower risk of angina pectoris (HR, 0.38; 95% CI, 0.17–0.86) was also observed in the cilostazol group. After multi-variable adjustment, cilostazol treatment independently predicted a lower risk of MCE. In conclusion, these results suggest cilostazol may have beneficial effects in patients with CAD or at a high risk of CV disease.

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.

Guided versus standard antiplatelet therapy in patients undergoing percutaneous coronary intervention: a systematic review and meta-analysis

BACKGROUND

Whether guided selection of antiplatelet therapy in patients undergoing percutaneous coronary intervention (PCI) is effective in improving outcomes compared with standard antiplatelet therapy remains controversial. We assessed the safety and efficacy of guided versus standard selection of antiplatelet therapy in patients undergoing PCI.

METHODS

For this systematic review and meta-analysis, from Aug 20 to Oct 25, 2020, we searched MEDLINE (via PubMed), Cochrane, Embase, and Web of Science databases for randomised controlled trials and observational studies published in any language that compared guided antiplatelet therapy, by means of platelet function testing or genetic testing, versus standard antiplatelet therapy in patients undergoing PCI. Two reviewers independently assessed study eligibility, extracted the data, and assessed risk of bias. Risk ratios (RRs) and 95% CIs were used with random-effects or fixed-effect models according to the estimated heterogeneity among studies assessed by the I² index. Coprimary endpoints were trial-defined primary major adverse cardiovascular events and any bleeding. Key secondary endpoints were all-cause death, cardiovascular death, myocardial infarction, stroke, definite or probable stent thrombosis, and major and minor bleeding. This study is registered with PROSPERO (CRD42021215901).

FINDINGS

3656 potentially relevant articles were screened. Our analysis included 11 randomised controlled trials and three observational studies with data for 20 743 patients. Compared with standard therapy, guided selection of antiplatelet therapy was associated with a reduction in major adverse cardiovascular events (RR 0·78, 95% CI 0·63-0·95, p=0·015) and reduced bleeding, although not statistically significant (RR 0·88, 0·77-1·01, p=0·069). Cardiovascular death (RR 0·77, 95% CI 0·59-1·00, p=0·049), myocardial infarction (RR 0·76, 0·60-0·96, p=0·021), stent thrombosis (RR 0·64, 0·46-0·89, p=0·011), stroke (RR 0·66, 0·48-0·91, p=0·010), and minor bleeding (RR 0·78, 0·67-0·92, p=0·0030) were reduced with guided therapy compared with standard therapy. Risks of all-cause death and major bleeding did not differ between guided and standard approaches. Outcomes varied according to the strategy used, with an escalation approach associated with a significant reduction in ischaemic events without any trade-off in safety, and a de-escalation approach associated with a significant reduction in bleeding, without any trade-off in efficacy.

INTERPRETATION

Guided selection of antiplatelet therapy improved both composite and individual efficacy outcomes with a favourable safety profile, driven by a reduction in minor bleeding, supporting the use of platelet function or genetic testing to optimise the choice of agent in patients undergoing PCI.

FUNDING

None.

Cilostazol: a Review of Basic Mechanisms and Clinical Uses

Primarily used in the treatment of intermittent claudication, cilostazol is a 2-oxyquinolone derivative that works through the inhibition of phosphodiesterase III and related increases in cyclic adenosine monophosphate (cAMP) levels. However, cilostazol has been implicated in a number of other basic pathways including the inhibition of adenosine reuptake, the inhibition of multidrug resistance protein 4, among others. It has been observed to exhibit antiplatelet, antiproliferative, vasodilatory, and ischemic-reperfusion protective properties. As such, cilostazol has been investigated for clinical use in a variety of settings including intermittent claudication, as an adjunctive for reduction of restenosis after coronary and peripheral endovascular interventions, and in the prevention of secondary stroke, although its widespread implementation for indications other than intermittent claudication has been limited by relatively modest effect sizes and lack of studies in western populations. In this review, we highlight the pleiotropic effects of cilostazol and the evidence for its clinical use.

Adjunctive Cilostazol to Dual Antiplatelet Therapy to Enhance Mobilization of Endothelial Progenitor Cell in Patients with Acute Myocardial Infarction: A Randomized, Placebo-Controlled EPISODE Trial

Background: Endothelial progenitor cells (EPCs) have the potential to protect against atherothrombotic event occurrences. There are no data to evaluate the impact of cilostazol on EPC levels in high-risk patients. Methods: We conducted a randomized, double-blind, placebo-controlled trial to assess the effect of adjunctive cilostazol on EPC mobilization and platelet reactivity in patients with acute myocardial infarction (AMI). Before discharge, patients undergoing percutaneous coronary intervention (PCI) were randomly assigned to receive cilostazol SR capsule (200-mg) a day (n = 30) or placebo (n = 30) on top of dual antiplatelet therapy (DAPT) with clopidogrel and aspirin. Before randomization (baseline) and at 30-day follow-up, circulating EPC levels were analyzed using flow cytometry and hemostatic measurements were evaluated by VerifyNow and thromboelastography assays. The primary endpoint was the relative change in EPC levels between baseline and 30-day. Results: At baseline, there were similar levels of EPC counts between treatments, whereas patients with cilostazol showed higher levels of EPC counts compared with placebo after 30 days. Cilostazol versus placebo treatment displayed significantly higher changes in EPC levels between baseline and follow-up (ΔCD133⁺/KDR⁺: difference 216%, 95% confidence interval (CI) 44~388%, p = 0.015; ΔCD34⁺/KDR⁺: difference 183%, 95% CI 25~342%, p = 0.024). At 30-day follow-up, platelet reactivity was lower in the cilostazol group compared with the placebo group (130 ± 45 versus 169 ± 62 P2Y12 Reaction Unit, p = 0.009). However, there were no significant correlations between the changes of EPC levels and platelet reactivity. Conclusion: Adjunctive cilostazol on top of clopidogrel and aspirin versus DAPT alone is associated with increased EPC mobilization and decreased platelet reactivity in AMI patients, suggesting its pleiotropic effects against atherothrombotic events (NCT04407312).

Bioresorbable Vascular Scaffolds Versus Drug-Eluting Stents for Diffuse Long Coronary Narrowings

Clinical benefits of bioresorbable vascular scaffold (BVS) implantation for long coronary lesions were not sufficiently evaluated. The efficacy and safety of BVS and metallic everolimus-eluting stent (EES) were compared for the treatment of long coronary narrowings. A total of 341 patients with diffuse long lesions (requiring device length ≥28 mm) were randomized to receive either BVS (n = 171) or EES (n = 170) implantation. The primary endpoint was major adverse cardiovascular events which included death from cardiac cause, myocardial infarction, device thrombosis, or ischemia-driven target-lesion revascularization at 12 months. The trial was terminated early because the manufacturer stopped supplying BVS. The mean lesion length was 32.2 ± 13.1 mm in the BVS group and 35.3 ± 13.0 mm in the EES group. The 12-month follow-up was completed in 332 patients (97.4%). At 12 months, the primary endpoint events occurred in 2 patients (1.2%) in the BVS group and in 4 patients (2.4%) in the EES group (hazard ratio = 0.49, 95% confidence interval = 0.09 to 2.67, p = 0.398). Definite or probable device thrombosis occurred in 1 patient (0.6%) in the BVS group and 1 patient (0.6%) in the EES group (hazard ratio = 1.00, 95% confidence interval = 0.06 to 15.94, p = 0.998). In conclusion, in patients with long native coronary artery disease, significant differences between BVS and EES were not observed regarding the primary composite endpoint of death from cardiac cause, myocardial infarction, device thrombosis, or target-lesion revascularization at 12 months. However, due to the early termination of this trial and a low number of events, the results cannot be considered clinically relevant (clinicalTrials.gov Identifier: NCT02796157).

Effects of Cilostazol-Based Triple Antiplatelet Therapy Versus Dual Antiplatelet Therapy After Coronary Drug-Eluting Stent Implantation: An Updated Meta-Analysis of the Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

The results of studies on cilostazol-based triple antiplatelet therapy (TAT) after drug-eluting stent (DES) implantation were inconsistent. To assess the effects of TAT compared with dual antiplatelet therapy (DAT) after DES/second-generation DES implantation, we performed a meta-analysis of randomized controlled trials (RCTs).

METHODS

All relevant studies evaluated were identified by searching the PubMed, EMBASE, Cochrane Library, and ISI Web of Science databases without time and language limitation. Subgroup analyses were performed to evaluate the efficacy and safety of TAT after second-generation DES implantation.

RESULTS

Eleven RCTs involving a total of 4684 patients were included. The meta-analysis showed TAT was associated with significant beneficial effects on angiographic findings of in-stent restenosis [risk ratio (RR) 0.645, 95% confidence interval (CI) 0.470-0.885; P = 0.007], in-segment restenosis (RR 0.606, 95% CI 0.450-0.817; P = 0.001), in-stent late loss (RR - 0.095, 95% CI - 0.136 to - 0.054; P < 0.0001), in-segment late loss (RR - 0.100, 95% CI - 0.139 to - 0.061; P < 0.0001), target lesion revascularization (TLR) (RR 0.570, 95% CI 0.430-0.755; P < 0.0001), and target vessel revascularization (TVR) (RR 0.523, 95% CI 0.380-0.719; P < 0.0001). No significant difference was found in outcomes of all-cause death, cardiac death, definite/probable stent thrombosis (ST), non-fatal myocardial infarction (MI), overall bleeding, and major bleeding between the two groups, as well as some minor adverse effects including palpitations, thrombocytopenia, neutropenia, and hepatic dysfunction. However, the incidence rate of rash, gastrointestinal disorders, and headache was significantly higher in TAT. The second-generation DES subgroup showed similar results, except for the indicators of all-cause death (RR 2.161, 95% CI 1.007-4.635; P = 0.048) and hepatic dysfunction (RR 0.176, 95% CI 0.031-0.995; P = 0.049).

CONCLUSIONS

Compared with DAT, cilostazol-based TAT can significantly improve the angiographic findings of in-stent and in-segment late loss, in-stent and in-segment restenosis, TLR, and TVR after DES/second-generation DES implantation. However, no benefits were observed in outcomes of all-cause death, cardiac death, ST, and MI.