Effects of cilostazol on late lumen loss and repeat revascularization after Palmaz-Schatz coronary stent implantation

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.

Microbe-Derived Butyrate and Its Receptor, Free Fatty Acid Receptor 3, But Not Free Fatty Acid Receptor 2, Mitigate Neointimal Hyperplasia Susceptibility After Arterial Injury

Background

Arterial restenosis after vascular surgery is a common cause of midterm restenosis and treatment failure. Herein, we aim to investigate the role of microbe‐derived butyrate, FFAR2 (free fatty acid receptor 2), and FFAR3 (free fatty acid receptor 3) in mitigating neointimal hyperplasia development in remodeling murine arteries after injury.

Methods and Results

C57BL/6 mice treated with oral vancomycin before unilateral femoral wire injury to deplete gut microbiota had significantly diminished serum and stool butyrate and more neointimal hyperplasia development after arterial injury, which was reversed by concomitant butyrate supplementation. Deficiency of FFAR3 but not FFAR2, both receptors for butyrate, exacerbated neointimal hyperplasia development after injury. FFAR3 deficiency was also associated with delayed recovery of the endothelial layer in vivo. FFAR3 gene expression was observed in multiple peripheral arteries, and expression was increased after arterial injury. Treatment of endothelial but not vascular smooth muscle cells with the pharmacologic FFAR3 agonist 1‐methylcyclopropane carboxylate stimulated cellular migration and proliferation in scratch assays.

Conclusions

Our results support a protective role for butyrate and FFAR3 in the development of neointimal hyperplasia after arterial injury and delineate activation of the butyrate‐FFAR3 pathway as a valuable strategy for the prevention and treatment of neointimal hyperplasia.

Clinical expert consensus document on quantitative coronary angiography from the Japanese Association of Cardiovascular Intervention and Therapeutics

Quantitative coronary angiography (QCA) remains to play an important role in clinical trials and post-marketing surveillance related to the safety and efficacy of new PCI devices. In this document, the current standard methodology of QCA is summarized. In addition, its history, recent development and future perspectives are also reviewed.

Comparison of cilostazol versus ticlopidine following coronary stenting in patients with coronary heart disease: A meta-analysis of randomized controlled trials

Previous studies have shown that the combination of cilostazol and aspirin may be a more effective regimen than ticlopidine plus aspirin in the prevention of late restenosis and acute or subacute stent thrombosis following coronary stenting; however, individually published results are inconclusive. The aim of this meta-analysis was to compare the differences in late restenosis and stent thrombosis between cilostazol plus aspirin and ticlopidine plus aspirin for patients with coronary heart disease (CHD) following coronary stenting. A literature search of Pubmed, Embase, Web of Science and Chinese BioMedicine (CBM) databases was conducted from 1998 to March 1, 2013 and statistical analysis was performed using Stata statistical software, version 12.0. Twelve randomized controlled trials were included in the study, with a total of 2,708 patients with CHD following coronary stenting. The patient population comprised 1,371 patients treated with cilostazol plus aspirin and 1,337 patients treated with ticlopidine plus aspirin. The meta-analysis showed that cilostazol plus aspirin demonstrated a lower rate of restenosis than ticlopidine plus aspirin [odds ratio (OR)=0.83, 95% confidence interval (CI)=0.69–0.99, P=0.047]. A significant difference was also observed in the average percent diameter stenosis between cilostazol plus aspirin and ticlopidine plus aspirin [standardized weight difference (SMD)= −0.57, 95% CI=−0.92, −0.23, P=0.001). However, there were no significant differences in the rates of acute or subacute stent thrombosis between cilostazol plus aspirin and ticlopidine plus aspirin. The present meta-analysis suggests that cilostazol plus aspirin may result in a lower restenosis rate and percent diameter stenosis than ticlopidine plus aspirin for patients with CHD following coronary stenting.

Antithrombotic Strategies in Endovascular Interventions: Current Status and Future Directions

Despite increasing numbers of endovascular interventions to treat arterial and venous disease, scant level 1 evidence is available regarding the role of antithrombotic and antiplatelet therapy in patients undergoing these procedures. The current practice in this regard is heterogeneous and has mainly been driven by data from coronary artery disease and percutaneous coronary intervention. This article discusses the role of antithrombotic and antiplatelet agents for endovascular intervention.

A better effect of cilostazol for reducing in-stent restenosis after femoropopliteal artery stent placement in comparison with ticlopidine

Purpose

The purpose of this study was to assess the preventive effect of cilostazol on in-stent restenosis in patients after superficial femoral artery (SFA) stent placement.

Materials and methods

Of 28 patients with peripheral arterial disease, who had successfully undergone stent implantation, 15 received cilostazol and 13 received ticlopidine. Primary patency rates were retrospectively analyzed by means of Kaplan–Meier survival curves, with differences between the two medication groups compared by log-rank test. A multivariate Cox proportional hazards model was applied to assess the effect of cilostazol versus ticlopidine on primary patency.

Results

The cilostazol group had significantly better primary patency rates than the ticlopidine group. Cumulative primary patency rates at 12 and 24 months after stent placement were, respectively, 100% and 75% in the cilostazol group versus 39% and 30% in the ticlopidine group (P = 0.0073, log-rank test). In a multivariate Cox proportional hazards model with adjustment for potentially confounding factors, including history of diabetes, cumulative stent length, and poor runoff, patients receiving cilostazol had significantly reduced risk of restenosis (hazard ratio 5.4; P = 0.042).

Conclusion

This retrospective study showed that cilostazol significantly reduces in-stent stenosis after SFA stent placement compared with ticlopidine.

Efficacy of cilostazol in reducing restenosis in patients undergoing contemporary stent based PCI: a meta-analysis of randomised controlled trials

AIMS

Cilostazol has been associated with reduction in restenosis in patients undergoing coronary and peripheral arterial angioplasty. Our objective was to evaluate the impact of cilostazol on restenosis in patients undergoing contemporary PCI with bare metal (BMS) or drug eluting stents (DES) and treated with aspirin and thienopyridine.

METHODS AND RESULTS

Ten randomised trials (n=2,809 patients) comparing triple antiplatelet therapy (aspirin, thienopyridine and cilostazol) with standard dual antiplatelet therapy were included. Summary risk ratios for restenosis, late loss, target lesion revascularisation (TLR) and target vessel revascularisation (TVR) were calculated using fixed-effects models. Cilostazol was associated with a significant reduction in late loss in BMS (mean difference 0.24 mm, 95% CI 0.15-0.33, p<0.001) and DES groups (mean difference 0.12 mm, 95% CI 0.07-0.18, p<0.001). Cilostazol therapy was associated with a significant reduction in angiographic restenosis (Odds ratio [OR] 0.52, 95% CI 0.41- 0.66, p<0.001) with consistent benefits in patients treated with BMS (OR 0.49, 95% CI 0.35-0.70, p<0.001) or DES (OR 0.54, 95% CI 0.38-0.76, p=0.001). Addition of cilostazol to dual antiplatelet therapy was associated with a significant reduction in TLR (OR 0.38, 95% CI 0.25-0.58, p<0.001), with no difference in subacute stent thrombosis (OR 1.91, 95% CI 0.33-11.08, p=0.47), or major bleeding (OR 0.87, 95% CI 0.44-1.74, P=0.69) but with an increased risk of skin rash (OR 3.67, 95% CI 1.86-7.24, p<0.001).

CONCLUSIONS

Cilostazol in addition to dual antiplatelet therapy is associated with a reduction in angiographic restenosis in patients undergoing stent based PCI. This inexpensive drug may be particularly beneficial in patients who are at high risk of restenosis and it should undergo further evaluation in large, definitive randomised controlled trials.

Cilostazol in addition to aspirin and clopidogrel improves long-term outcomes after percutaneous coronary intervention in patients with acute coronary syndromes: a randomized, controlled study

BACKGROUND

Cilostazol has been widely used to prevent peripheral vascular events, and its antiplatelet mechanisms may different from aspirin and clopidogrel. We hypothesized that cilostazol in addition to aspirin and clopidogrel effectively reduces systemic ischemic events after percutaneous coronary intervention (PCI) in high-risk patients.

METHODS

In this prospective study, 1,212 patients with acute coronary syndromes were randomly assigned to receive either standard dual-antiplatelet treatment with aspirin and clopidogrel (n = 608) or triple-antiplatelet therapy with the addition of a 6-month course of cilostazol (n = 604) after successful PCI. The primary end point was a composite of cardiac death, nonfatal myocardial infarction, stroke, or target vessel revascularization (TVR) at 1 year after randomization. The secondary end points were TVR and hemorrhagic events.

RESULTS

Triple-antiplatelet treatment was associated with a significantly lower incidence of the primary end points (10.3% vs 15.1%; P = .011). The need for TVR was similar between patients who received triple- and dual-antiplatelet treatment (7.9% vs 10.7%; P = .10). Multivariate analysis showed that female patients and clinically or angiographically high-risk patients benefited more from the triple-antiplatelet treatment. There were no significant differences between the 2 regimens in terms of the risks for major and minor bleeding.

CONCLUSIONS

For patients with acute coronary syndromes, triple-antiplatelet therapy consisting of cilostazol, aspirin, and clopidogrel reduced long-term cardiac and cerebral events after PCI, especially for patients with high-risk profiles.

Systematic review and meta-analysis of randomized clinical trials appraising the impact of cilostazol after percutaneous coronary intervention

BACKGROUND

Drug-eluting stents reduce the risk of restenosis after percutaneous coronary intervention (PCI) but may pose a risk of thrombosis. Cilostazol, an oral antiplatelet agent with pleiotropic effects including inhibition of neointimal hyperplasia, could hold the promise of preventing both restenosis and thrombosis. We systematically reviewed randomized clinical trials (RCTs) on the angiographic and clinical impact of cilostazol after PCI.

METHODS

We searched RCT in BioMedCentral, CENTRAL, clinicaltrials.gov, EMBASE, and PubMed (November 2007). Coprimary end points were binary angiographic restenosis and repeat revascularization, abstracted and pooled by means of random-effect relative risks (RRs). Small study/publication bias was appraised with multiple methods.

RESULTS

A total of 23 RCTs were included (5428 patients), with median follow-up of 6 months. Pooled analysis showed that cilostazol was associated with statistically significant reductions in binary angiographic restenosis (RR = 0.60 [0.49-0.73], P < .001) and repeat revascularization (RR = 0.69 [0.55-0.86], P = .001). Cilostazol appeared also safe, with no significant increase in the risk of stent thrombosis (RR = 1.35 [0.71-2.57], P = .36) or bleeding (RR = 0.71 [0.43-1.16], P = .17). However, small study bias was evident for both binary restenosis (P < .001) and repeat revascularization (P < .001), suggesting that at least part of the apparent benefits of cilostazol could be due to this type of confounding effect.

CONCLUSIONS

Cilostazol appears effective and safe in reducing the risk of restenosis and repeat revascularization after PCI, but available evidence is limited by small study effects. Awaiting larger RCTs, this inexpensive treatment can be envisaged in selected patients in which drug-eluting stents are contraindicated or when there is a need for neointimal hyperplasia inhibition.

The vascular effects of cilostazol

Cilostazol is a phosphodiesterase III inhibitor with pharmacological effects that include vasodilation, inhibition of platelet activation and aggregation, inhibition of thrombosis, increased blood flow to the limbs, improvement in serum lipids with lowering of triglycerides and elevation of high density lipoprotein cholesterol, and inhibition of vascular smooth muscle cell growth. Cilostazol has been shown in multiple randomized clinical trials to result in decreased claudication and improved ability to walk in patients with peripheral arterial disease. In addition, cilostazol has been shown in multiple randomized clinical trials to decrease restenosis in the setting of coronary stent implantation. The purpose of the present paper was to review the vascular effects of cilostazol and to present results of the major clinical trials of the use of cilostazol in peripheral arterial disease and percutaneous coronary intervention with stent implantation.

Drug-Eluting Stents

The introduction of percutaneous transluminal coronary angioplasty has revolutionized the field of cardiology by providing patients with coronary artery disease immediate and effective therapy. Overshadowing the early success of angioplasty was the high rate of angiographic restenosis and recurrent symptoms at 6 months. The use of stents reduced the incidence of restenosis; however, the rise in the number of patients undergoing percutaneous interventions produced a new problem of restenosis occurring within the stent: in-stent restenosis (ISR). Mechanical approaches, including directional and rotational atherectomy and systemic pharmacotherapy, have failed to demonstrate a reduction in ISR in randomized clinical trials. Intravascular brachytherapy is currently the only approved therapy for ISR, although this treatment has numerous unresolved questions and is not effective in a large percent of patients. Drug-eluting stents have reduced the incidence of restenosis by providing localized therapy to the targeted lesion without systemic toxicity. The purpose of this review is to synthesize data from major clinical trials involving the 2 most successful agents used in the prevention of restenosis: sirolimus and paclitaxel. The cellular and molecular mechanisms of both ISR and restenosis postangioplasty derived from animal models will be introduced. Second, an overview of 3 alternate interventions that attempt to reduce the rates of restenosis is presented. Finally, the major randomized, controlled trials involving sirolimus and paclitaxel are described, and their clinical implications and use as a possible solution in the prevention of restenosis is discussed.

Effects of angiotensin-converting enzyme inhibitors or an angiotensin receptor blocker in combination with aspirin and cilostazol on in-stent restenosis

It remains to be determined whether adding an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB) to antiplatelet therapy has a therapeutic benefit on in-stent restenosis. After successful coronary stenting, 165 patients (167 lesions) were randomly assigned to a basal (aspirin 162 mg + cilostazol 200 mg/day), ACEI (basal treatment + quinapril 10 mg or perindopril 4 mg/day), or ARB (basal treatment + losartan 50 mg/day) treatment group. Quantitative coronary angiography was performed before, immediately following, and 6 months after stenting. Follow-up coronary angiography was completed in 126 patients (128 lesions). Restenosis rates tended to be higher (12, 26, and 12% for the basal, ACEI, and ARB groups, respectively), and target lesion revascularization rates were higher in the ACEI group than in the other groups (9, 23,* and 5%, respectively, *P < 0.05 versus basal group). Moreover, late lumen loss was higher in the ACEI group than in the basal group (0.60 +/- 0.55, 0.98 +/- 0.61* and 0.73 +/- 0.64 mm in the basal, ACEI, and ARB groups, respectively). The combinations of an ACEI or ARB with aspirin and cilostazol are ineffective for the prevention of in-stent restenosis, and an ACEI may even promote intimal proliferation after stent implantation.

In stent restenosis: bane of the stent era

The long term outcome of stent implantation is affected by a process called in stent restenosis (ISR). Multiple contributory factors have been identified, but clear understanding of the overall underlying mechanism remains an enigma. ISR progresses through several different phases and involves numerous cellular and molecular constituents. Platelets and macrophages play a central role via vascular smooth muscle cell migration and proliferation in the intima to produce neointimal hyperplasia, which is pathognomic of ISR. Increased extracellular matrix formation appears to form the bulk of the neointimal hyperplasia tissue. Emerging evidence of the role of inflammatory cytokines and suppressors of cytokine signalling make this an exciting and novel field of antirestenosis research. Activation of Akt pathway triggered by mechanical stretch may also be a contributory factor to ISR formation. Prevention of ISR appears to be a multipronged attack as no therapeutic "magic bullet" exists to block all the processes in one go.

Cilostazol reduces target lesion revascularization after percutaneous transluminal angioplasty in the femoropopliteal artery

BACKGROUND

Although percutaneous transluminal angioplasty (PTA) is being widely used for the treatment of stenosis of peripheral arteries, the high in-stent restenosis rate (50-60%) in the femoropopliteal artery still remains an unsolved issue. Cilostazol is a unique antiplatelet drug that has vasodilatory effects and inhibits smooth muscle cell proliferation.

METHODS AND RESULTS

A total of 141 consecutive patients scheduled for PTA in the femoropopliteal artery between September 1999 and April 2004 were retrospectively analyzed for the use of cilostazol. Target lesion revascularization (TLR) was defined as repeated PTA in patients who had a recurrence of symptoms with diameter stenosis >50% by angiography. Patient and lesion characteristics were similar between the cilostazol (+) and cilostazol (-) groups. Use of other medications was similar between the groups, except for ticlopidine, which was more frequently used in the cilostazol (-) than in the cilostazol (+) group (15% vs 61%, p<0.01). TLR was significantly reduced in the cilostazol (+) group (12% [8/68] vs 32% [23/73], p<0.01).

CONCLUSIONS

Although this study was retrospective and nonrandomized, the results suggest that cilostazol reduces TLR after PTA in the femoropopliteal artery.

RACTS: a prospective randomized antiplatelet trial of cilostazol versus ticlopidine in patients undergoing coronary stenting: long-term clinical and angiographic outcome

We compared the efficacy of cilostazol for the prevention of late restenosis and acute or subacute stent thrombosis with that of ticlopidine. Cilostazol has been used for antiplatelet therapy after coronary stent implantation, but the results are controversial. Patients scheduled for stent implantation were randomly assigned to receive either cilostazol (100 mg twice daily for 6 months, n=201) or ticlopidine (250 mg twice daily for 1 month, n=196). All patients also received oral aspirin (100 mg once daily for 6 months). Coronary angiography was performed at baseline and immediately and 6 months after coronary stenting. Clinical follow-up was continued up to 9 months postprocedure. There was no significant difference in the composite incidence of death, myocardial infarction, stroke, and stent thrombosis between the 2 groups [cilostazol (1.5%) versus ticlopidine (3.6%), P=0.216], but the target lesion revascularization rate per patient was significantly lower in the cilostazol group than in the ticlopidine group (22.9% vs 32.7%, P=0.030) 9 months post-coronary stenting. Medication withdrawn because of drug-related side effects tended to be higher in the ticlopidine group than that in the cilostazol group (3.5% vs 8.2%, P=0.054). At follow-up angiography, the minimal luminal diameters (2.31+/-1.06 vs 2.10+/-1.16, P=0.057) tended to be larger and the restenosis rates lower (23.3% vs 30.9%, P=0.086) in the cilostazol group than in the ticlopidine group. Aspirin plus cilostazol is a comparable antithrombotic regimen to aspirin plus ticlopidine after elective coronary stenting, but the rate of target lesion revascularization was significantly lower in the cilostazol group than in the ticlopidine group.

Effects of Cilostazol on Human Venous Smooth Muscle

In this study, we evaluated the effect of therapeutic doses of cilostazol on human venous smooth muscle. Saphenous vein rings (two to four per patient sample) were suspended in tissue baths for isometric tension recordings. At the beginning of the experiment, optimal tension for isometric contraction was achieved for each ring in a stepwise fashion in the presence of norepinephrine (10(-2) M). Norepinepherine was then added cumulatively in half-molar increments and isometric tension developed by the rings was measured, thereby obtaining a dose-response curve. Following washout and reequilibration, the rings were precontracted with a 30-50% submaximal dose of norepinepherine determined from the dose-response curve and allowed to contract until a stable plateau was reached. Cilostazol was then added in a cumulative manner (680-2,720 microg/L), and the tension generated was recorded. A total of 76 venous rings were tested, and all relaxed in the presence of cilostazol. The amount of relaxation increased as the concentration of cilostazol increased. Relaxation of 15 +/- 1.9% (mean +/- SEM) at low cilostazol doses (680 microg/L) to 37+/-3% at high cilostazol doses (2,720 microg/L) was demonstrated. A second finding of this study was demonstrated when the patient samples were divided according to the presence or absence of risk factors for arteriosclerosis. The specific risk factors examined included diabetes mellitus, smoking, hypercholesterolemia, and hypertension. The presence or absence of hypertension (n = 52) or hypercholesterolemia (n = 18) did not affect the amount of relaxation of the venous rings. Smokers (n = 46) had less relaxation 16 +/- 2.4% (680 microg/L) to 41 +/- 3.6% (2,720 microg/L) compared to nonsmokers (n = 53) who relaxed 22 +/- 3.5% (680 microg/L) to 48 +/- 5.7% (2720 microg/L). This did not reach statistical significance at any concentration cilostazol (p = 0.11-0.18). Diabetics (n = 53) did have statistically significantly less relaxation at every concentration of cilostazol compared to nondiabetics (n = 11, p < 0.05). All venous rings relaxed in the presence of cilostazol. Veins of nondiabetics relaxed statistically significantly more than those of diabetics. Smokers had less relaxation than non-smokers, but this was not statistically significant. We are the first to demonstrate that human venous smooth muscle cells undergo relaxation when exposed to therapeutic concentrations of cilostazol.

Pharmacological treatment for prevention of restenosis

Coronary artery disease (CAD) is the leading cause of mortality and morbidity among adults in the Western world. Coronary artery bypass grafting and percutaneous coronary interventions (PCI) have gained widespread acceptance for the treatment of symptomatic CAD. There has been an explosive growth worldwide in the utilisation of PCI, such as balloon angioplasty and stenting, which now accounts for over 50% of coronary revascularisation. Despite the popularity of PCI, the problem of recurrent narrowing of the dilated artery (restenosis) continues to vex investigators. In recent years, significant advances have occurred in the understanding of restenosis. Two processes seem to contribute to restenosis: remodelling (vessel size changes) and intimal hyperplasia (vascular smooth muscle cell [VSMC] proliferation and extracellular matrix [ECM] deposition). Despite considerable efforts, pharmacological approaches to decrease restenosis have been largely unsuccessful and the only currently applied modality to reduce the restenosis rate is stenting. However, stenting only prevents remodelling and does not inhibit intimal hyperplasia. Several potential targets for inhibiting restenosis are currently under investigation including platelet activation, the coagulation cascade, VSMC proliferation and migration, and ECM synthesis. In addition, new approaches for local drug therapy, such as drug eluting stents, are currently being evaluated in preclinical and clinical studies. In this article, we critically review the current status of drugs that are being evaluated for restenosis at various stages of development (in vitro, preclinical animal models and human trials).

Randomized Comparison of Cilostazol vs Ticlopidine for Antiplatelet Therapy After Coronary Stenting

BACKGROUND

Cilostazol and ticlopidine are commonly prescribed for prevention of thrombosis after coronary stenting, but few studies have compared them.

METHODS AND RESULTS

In the present study 642 patients who underwent stenting were randomized to treatment either with cilostazol + aspirin (C group, 321 patients) or ticlopidine + aspirin (T group, 321 patients). Quantitative coronary angiography (QCA) was performed immediately after stenting and at the 6-month follow-up. Treatment was continued until follow-up angiography. Baseline patient characteristics did not differ significantly. With the exception of a higher rate of stenting in a venous graft in the C group, there were no differences in angiographic characteristics or stent type. Baseline QCA analysis of the reference diameter, minimal lumen diameter (MLD) showed no significant differences. Follow-up QCA analysis of the MLD showed no significant differences. There were also no differences in restenosis or target lesion revascularization rates, or in the incidence of adverse reactions. However, the rate of subacute thrombosis (SAT) was significantly higher in the C group than in the T group (2% vs 0.3%, p=0.02).

CONCLUSION

In the present study there was a similar restenosis rate with cilostazol or ticlopidine, but the rate of SAT was significantly higher with cilostazol. There was no significant difference in adverse reactions.

Cilostazol, clopidogrel or ticlopidine to prevent sub-acute stent thrombosis: a meta-analysis of randomized trials

BACKGROUND

Sub-acute thrombosis is a serious complication of coronary artery stenting. Clopidogrel plus aspirin is the accepted prophylactic regimen, but has yet to be proven superior to ticlopidine plus aspirin, and a new regimen combining cilostazol and aspirin has been introduced.

METHODS

We conducted a meta-analysis of all trials that compared >or=2 oral anti-thrombotic strategies in patients undergoing coronary stent placement to determine which treatment optimally prevents adverse cardiac events in the 30 days following stent insertion. We used meta-regression to compare all strategies to a shared control strategy: ticlopidine plus aspirin. We also compared randomized trials to historically controlled and other non-randomized trials. We conducted sensitivity analysis and subgroup analysis to assess for possible heterogeneity.

RESULTS

In comparison to ticlopidine plus aspirin the odds-ratios for cardiac events, with 95% confidence intervals were: aspirin alone, 4.29 (3.09-5.97), coumadin plus aspirin, 2.65 (2.18-3.21), clopidogrel plus aspirin, 1.06 (0.86-1.31), cilostazol plus aspirin, 0.73 (0.47-1.14). Among trials that compared clopidogrel plus aspirin to ticlopidine plus aspirin, historically controlled trials were statistically distinct from randomized trials. The analysis of cilostazol was sensitive to the small size of the included studies.

CONCLUSIONS

Neither clopidogrel plus aspirin nor cilostazol plus aspirin can be statistically distinguished from ticlopidine plus aspirin for the prevention of adverse cardiac events in the 30 days after stenting. A randomized trial including cilostazol is warranted.

Balloon angioplasty plus cilostazol administration versus primary stenting of small coronary artery disease: Final results of COMPASS

Efficacy of primary stenting in small coronary artery disease is still controversial. Cilostazol has been reported to control restenosis after balloon angioplasty (BA). The aim was to compare primary stenting with BA plus cilostazol administration in small coronary artery disease. Of 106 lesions located in small coronary artery (reference < 3.0 mm), 50 lesions were randomly assigned to the stenting and 56 lesions to the BA-cilostazol group. Multilink stent was implanted in the stenting group. In the BA-cilostazol group, cilostazol (200 mg/day) without aspirin was administered for 6 months after BA. Ticlopidine was given for 1 month when bailout stent was implanted. Serial quantitative angiography was performed at the procedure and 6 months. The primary endpoint was 6-month angiographic restenosis. Clinical event rates at 1 year were also assessed. Baseline characteristics were similar. All procedures were successful. Bailout stenting was performed in three lesions in the BA-cilostazol group. No side effects of cilostazol were observed. Postprocedural lumen diameter was significantly larger (2.69 vs. 2.03 mm; P < 0.0001) in the stenting group. However, the follow-up lumen diameter was not different (1.76 vs. 1.85 mm, stenting vs. BA-cilostazol). Although the difference was not statistically significant, restenosis rate was lower in the BA-cilostazol group (13.2% vs. 24.5%; P = 0.11). Subacute thrombosis occurred in one patient and target revascularization rate was higher in the stenting group (22.0% vs. 10.7%; P = 0.10). BA plus cilostazol administration seems to be a favorable strategy for small coronary artery disease.

Effects of Antiplatelet Agents on Subacute Thrombosis and Restenosis After Successful Coronary Stenting-A Randomized Comparison of Ticlopidine and Cilostazol-

BACKGROUND

A prospective randomized study compared the preventive effects of ticlopidine plus aspirin therapy versus cilostazol plus aspirin therapy on subacute thrombosis (SAT) and restenosis after coronary stenting.

METHODS AND RESULTS

After successful stenting of 327 coronary lesions in 282 consecutive patients, the patients were randomized to receive ticlopidine (200 mg/day) or cilostazol (200 mg/day). Aspirin (81 mg/day) was administered concomitantly in both groups. SAT occurred in 1 patient in the ticlopidine group (0.7%) and in 8 patients in the cilostazol group (5.6%, p=0.037). Based on follow-up angiography, restenosis occurred in 30 patients (23.3%) in the ticlopidine group and 35 patients (26.9%) in the cilostazol group (NS). The late loss was significantly smaller in the cilostazol group than the ticlopidine group (1.08+/-0.95 mm vs 0.78+/-0.93 mm, respectively, p=0.037). No significant differences between the 2 groups were observed with respect to the rates of total death, non-fatal cardiovascular events, or bleeding complications.

CONCLUSION

The ticlopidine group showed significantly less SAT after stenting compared with the cilostazol group. After 6 months of treatment, the inhibition of neointimal proliferation was greater in the cilostazol group than in the ticlopidine group, but the prevention of restenosis was not confirmed.

Debulking and stenting versus debulking only of coronary artery disease in patients treated with cilostazol (final results of ESPRIT)

Stenting inhibits vascular constrictive remodeling after directional coronary atherectomy (DCA). Cilostazol has been reported to control neointimal proliferation after stenting. This study's aim was to examine the effect of debulking and stenting with antirestenotic medication on restenosis. After optimal DCA, 117 lesions were randomly assigned to either the DCA with stent (DCA-stent) (58 lesions) group or the DCA only (59 lesions) group. Multilink stents were implanted in the DCA-stent group. Cilostazol (200 mg/day) without aspirin was administered to both groups for 6 months. Ticlopidine (200 mg/day) was given to the DCA-stent group for 1 month. Serial quantitative angiography and intravascular ultrasound (IVUS) were performed at the time of the procedure and at 6-month follow-up. The primary end point was 6-month angiographic restenosis. Clinical event rates at 1 year were also assessed. Baseline characteristics were similar. All procedures were successful. No adverse effects to cilostazol were observed. Postprocedural lumen diameter was significantly larger (3.27 vs 2.92 mm; p <0.0001) in the DCA-stent group. However, the follow-up lumen diameter was not significantly different (2.53 vs 2.41 mm, DCA-stent vs DCA). IVUS revealed that intimal proliferation was significantly larger in the DCA-stent group (4.2 vs 1.5 mm(2); p <0.0001), which accounted for the similar follow-up lumen area (6.5 vs 7.1 mm(2)). The restenosis rate was low in both groups (5.4% vs 8.9%), and the difference was not significant. Clinical event rates at 1 year were also not significantly different. These results suggest that optimal lesion debulking by DCA does not always need adjunctive stenting if cilostazol is administered.

Can we prevent in-stent restenosis?

Nowadays stent placement has replaced balloon angioplasty as the most commonly performed percutaneous coronary interventional procedure, mainly because of its better acute and chronic outcome. As a result, in-stent restenosis (ISR) has become a widespread problem. The incidence of ISR varies from 10% to 50% and depends on the absence or presence of several risk factors, such as small vessel size, longer lesions, and diabetes. Intravascular ultrasound studies have demonstrated that ISR is mainly caused by neointimal proliferation; consequently, this pathologic process has become the target of many preventive and therapeutic approaches. This article provides an overview of such management strategies, highlighting the rather disappointing experiences with mechanical and systemic drug therapies; the relative merits and disadvantages of intracoronary radiation; and the exciting yet realistic promise, embodied by the recent advancements in drug-eluting stent technology, of potentially eradicating ISR in the near future.

Cilostazol (pletal): a dual inhibitor of cyclic nucleotide phosphodiesterase type 3 and adenosine uptake

Cilostazol (Pletal), a quinolinone derivative, has been approved in the U.S. for the treatment of symptoms of intermittent claudication (IC) since 1999 and for related indications since 1988 in Japan and other Asian countries. The vasodilatory and antiplatelet actions of cilostazol are due mainly to the inhibition of phosphodiesterase 3 (PDE3) and subsequent elevation of intracellular cAMP levels. Recent preclinical studies have demonstrated that cilostazol also possesses the ability to inhibit adenosine uptake, a property that may distinguish it from other PDE3 inhibitors, such as milrinone. Elevation of interstitial and circulating adenosine levels by cilostazol has been found to potentiate the cAMP-elevating effect of PDE3 inhibition in platelets and smooth muscle, thereby augmenting antiplatelet and vasodilatory effects of the drug. In contrast, elevation of interstitial adenosine by cilostazol in the heart has been shown to reduce increases in cAMP caused by the PDE3-inhibitory action of cilostazol, thus attenuating the cardiotonic effects. Cilostazol has also been reported to inhibit smooth muscle cell proliferation in vitro and has been demonstrated in a clinical study to favorably alter plasma lipids: to decrease triglyceride and to increase HDL-cholesterol levels. One, or a combination of several of these effects may contribute to the clinical benefits and safety of this drug in IC and other disease conditions secondary to atherosclerosis. In eight double-blind randomized placebo-controlled trials, cilostazol significantly increased maximal walking distance, or absolute claudication distance on a treadmill. In addition, cilostazol improved quality of life indices as assessed by patient questionnaire. One large randomized, double-blinded, placebo-controlled, multicenter competitor trial demonstrated the superiority of cilostazol over pentoxifylline, the only other drug approved for IC. Cilostazol has been generally well-tolerated, with the most common adverse events being headache, diarrhea, abnormal stools and dizziness. Studies involving off-label use of cilostazol for prevention of coronary thrombosis/restenosis and stroke recurrence have also recently been reported.

Effects of a single oral dose of cilostazol on epicardial coronary arteries and hemodynamics in humans

Cilostazol, a novel cyclic adenosine monophosphate phosphodiesterase type III inhibitor, has been developed as an antiplatelet drug with a vasodilating action on peripheral arteries. The present study was designed to test, in humans, whether cilostazol can dilate the epicardial coronary arteries and what are its hemodynamic effects. Eight patients with chest pain syndrome were subjected to serial quantitative coronary arteriography immediately before and at 30, 60 and 150min after a single oral dose of cilostazol (200mg). Luminal cross-sectional areas (mm2) at the proximal and distal sites of major coronary arteries (6 segments at each sampling time) were significantly increased at 150 min after taking the drug. The percent increases relative to the baseline values were 25+/-7 (6.8+/-0.8-->8.3+/-1.0*) and 42+/-7% (2.1+/-0.3-->3.0+/-0.4*) in the right coronary artery, 24+/-5 (5.1+/-0.7-->6.1+/-0.8*) and 28+/-10% (1.6+/-0.31-->9+/-0.3*) in the left anterior descending artery, and 14+/-6 (5.9+/-0.9-->6.6+/-0.9*) and 24+/-10% (1.3+/-0.2-->1.5+/-0.2*) in the left circumflex artery, respectively (*p<0.05 vs baseline). This action, relative to that of nitroglycerine, was between 27% and 54%. Moreover, small but sustained decreases in systolic pulmonary pressure and stroke work index were observed. Thus, cilostazol has a mild coronary vasodilating action with minimal hemodynamic effects, thereby giving it a possible role in the treatment of coronary artery disease.

Cilostazol for prevention of thrombosis and restenosis after intracoronary stenting

OBJECTIVE

To evaluate the potential use of cilostazol in intracoronary stenting.

DATA SOURCES

Clinical literature was accessed through MEDLINE (1966-March 2001). Key search terms included cilostazol, intracoronary stenting, and coronary angioplasty. Abstracts of clinical trials presented at major cardiology professional association meetings were also reviewed.

DATA SYNTHESIS

Intracoronary stent placement represents the fastest growing medical device implant. Complications of stent implantation include acute and subacute vessel closure, as well as late restenosis. Currently, antiplatelet agents are used for preventive therapy. Cilostazol is a vasodilating antiplatelet agent that reversibly inhibits platelet aggregation induced by many factors. In seven randomized trials comparing cilostazol with either aspirin or ticlopidine, cilostazol was found to be superior to aspirin and equivalent to ticlopidine in decreasing both cardiac events and rates of restenosis. In addition, cilostazol was found to be well tolerated, with no reports of adverse hematologic events.

CONCLUSIONS

Although further comparative trials are required, cilostazol appears to be a safe and effective alternative to clopidogrel and glycoprotein IIb/IIIa receptor antagonists following intracoronary stent implantation.