Impact of cilostazol on clinical and angiographic outcome after primary stenting for acute myocardial infarction

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.

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 inhibits cytokine-induced nuclear factor-kappaB activation via AMP-activated protein kinase activation in vascular endothelial cells

AIMS

Cilostazol is a selective inhibitor of phosphodiesterase 3 that increases intracellular cyclic AMP (cAMP) levels and activates protein kinase A, thereby inhibiting platelet aggregation and inducing peripheral vasodilation. We hypothesized that cilostazol may prevent inflammatory cytokine induced-nuclear factor (NF)-kappaB activation by activating AMP-activated protein kinase (AMPK) in vascular endothelial cells.

METHODS AND RESULTS

Cilostazol was observed to activate AMPK and its downstream target, acetyl-CoA carboxylase, in human umbilical vein endothelial cells (HUVEC). Phosphorylation of AMPK with cilostazol was not affected by co-treatment with an adenylate cyclase inhibitor, SQ 22536, and a cell-permeable cAMP analogue, pCTP-cAMP, did not induce AMPK phosphorylation and had no effect on cilostazol-induced AMPK phosphorylation, suggesting that cilostazol-induced AMPK activation occurs through a signalling pathway independent of cyclic AMP. Cilostazol also dose-dependently inhibited tumour necrosis factor alpha (TNFalpha)-induced NF-kappaB activation and TNFalpha-induced I kappa B kinase activity. Furthermore, cilostazol attenuated the TNFalpha-induced gene expression of various pro-inflammatory and cell adhesion molecules, such as vascular cell adhesion molecule-1, E-selectin, intercellular adhesion molecule-1, monocyte chemoattractant protein-1 (MCP-1), and PECAM-1 in HUVEC. RNA interference of AMPK alpha 1 or the AMPK inhibitor compound C attenuated cilostazol-induced inhibition of NF-kappaB activation by TNFalpha.

CONCLUSION

In the light of these findings, we suggest that cilostazol might attenuate the cytokine-induced expression of adhesion molecule genes by inhibiting NF-kappaB following AMPK activation.

The cardioprotective effect of a statin and cilostazol combination: relationship to Akt and endothelial nitric oxide synthase activation

BACKGROUND

Atorvastatin (ATV) protects against ischemia-reperfusion by upregulating Akt and subsequently, endothelial nitric oxide synthase (eNOS) phosphorylation at Ser-1177. However, when given orally, high doses of ATV (10 mg/kg/d) are needed to achieve maximal protective effect in the rat. Protein kinase A (PKA) also phosphorylates eNOS at Ser-1177. As PKA activity depends on cAMP, cilostazol (CIL), a phosphodiesterase type III inhibitor, may stimulate NO production by activating PKA.

HYPOTHESIS

CIL and ATV may have synergistic effects on eNOS phosphorylation and myocardial infarct size (IS) reduction.

METHODS

Sprague-Dawley rats received 3-day oral pretreatment with: (1) water; (2) low dose ATV (2 mg/kg/d); (3) CIL (20 mg/kg/d): (4) ATV+CIL. Rats underwent 30 min coronary artery occlusion and 4 h reperfusion, or hearts explanted for immunoblotting without being subjected to ischemia. Area at risk (AR) was assessed by blue dye and IS by triphenyl-tetrazolium-chloride.

RESULTS

Body weight and the size of AR were comparable among groups. There were no significant differences among groups in mean blood pressure and heart rate. CIL, but not ATV, reduced IS. IS in the ATV+CIL group was significantly smaller than the other three groups (P < 0.001 for each comparison). ATV, CIL and their combination did not affect total eNOS expression. ATV at 2 mg/kg/d did not affect Ser-1177 P-eNOS levels, whereas CIL increased it (258 +/- 15%). The level of myocardial P-eNOS levels was highest in the ATV+CIL group (406 +/- 7%).

CONCLUSIONS

ATV and CIL have synergistic effect on eNOS phosphorylation and IS reduction. By increased activation of eNOS, CIL may augment the pleiotropic effects of statins.

Impact of chronotropic effect of cilostazol after acute myocardial infarction: insights from change in left ventricular volume and function

BACKGROUND

Cilostazol, a phosphodiesterase inhibitor, is an antiplatelet agent with positive chronotropic effect, the impact of which on left ventricular (LV) volume and function in acute myocardial infarction (AMI) was evaluated in the present study.

METHODS AND RESULTS

In 56 patients with AMI treated with primary coronary stenting, serial echocardiographic studies within 24 h and at 6 months were performed. Patients received a conventional antiplatelet regimen either without cilostazol (group 1, n=29) or with cilostazol (group 2, n=27). At 6 months, the difference in the change in heart rate between group 1 and group 2 was statistically significant (9.9 beats/min; p=0.04). However, changes in LV end-systolic volume (LVESV) (7.1+/-8.2 vs 10.0+/-21.7 ml, p=0.60), LV ejection fraction (EF) (8.2+/-9.9 vs 9.0+/-12.6%, p=0.85) and the ratio of early mitral inflow velocity to the mitral annular velocity (E/E') (0.6+/-3.7 vs -1.7+/-3.2) were not different between the 2 groups. Cardiac event rate was similar between the 2 groups. On multivariate regression analyses, cilostazol therapy had no significant influence on the changes in LVESV, LVEF or E/E'.

CONCLUSIONS

In this study, the addition of cilostazol on conventional drug therapy had no adverse influence on LV remodeling or LV function after AMI.

Reevaluating the role of phosphodiesterase inhibitors in the treatment of cardiovascular disease

First developed for clinical use in the late 1980s, the phosphodiesterase inhibitors were found to increase the levels of the ubiquitous second messenger cyclic adenosine monophosphate and could effect changes in vascular tone, cardiac function, and other cellular events. After several early studies using high doses of phosphodiesterase inhibitors in patients with severe heart failure suggested adverse consequences, they fell out of favor. However, recent investigations of phosphodiesterase inhibitors in patients with intermittent claudication have demonstrated profound benefits. Furthermore, these agents have proven useful in prevention of cerebral infarction and coronary restenosis, and their use in the treatment of heart failure is being reevaluated. The reemergence of phosphodiesterase inhibitors can be attributed to a better understanding of dosing and drug-specific pharmacology, the use of concomitant medications, and a recognition of unique ancillary properties; however, their use still requires caution.

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.

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.

Evaluation of the percusurge guardwire plus temporary occlusion and aspiration system during primary angioplasty in acute myocardial infarction

Thirty patients with acute myocardial infarction (AMI) underwent primary angioplasty under distal protection of PercuSurge GuardWire Plus Temporary Occlusion and Aspiration System. Before angioplasty, protection of the distal circulation was achieved with the system, followed by balloon angioplasty and/or stenting and debris aspiration. Technical device success was 100%. Distal occlusion was well tolerated in all patients. Mean total distal occlusion time was 7.3 +/- 5.4 min. Macroscopically visible debris was aspirated from 29 cases (96.7%). Postprocedural Thrombolysis in Myocardial Infarction flow grade 3 was achieved in all cases (100%, vs. 16.7% at baseline). Myocardial blush flow grade 3 was achieved in 26 cases (86.7%). Regression of ST segment elevation >/= 50% was shown in 23 cases (76.7%). No patient developed angiographic evidence of no-reflow or distal embolization. Both angiographic and procedural success were 100%. The system is feasible, safe, and effective for distal protection against embolism during primary angioplasty in AMI.

Randomized comparison of cilostazol versus ticlopidine hydrochloride for antiplatelet therapy after coronary stent implantation for prevention of late restenosis

BACKGROUND

Cilostazol is a newly developed antiplatelet drug that has been widely applied for clinical use. Its antiplatelet action appears to be mainly related to inhibition of intracellular phosphodiesterase activity. Recently, cilostazol has been used for antiplatelet therapy after coronary stent implantation. However, its evaluation has not been established yet.

METHODS

This prospective randomized trial was designed to investigate the efficacy of cilostazol for the prevention of late restenosis and acute or subacute stent thrombosis in comparison with ticlopidine hydrochloride. One hundred thirty consecutive patients, scheduled for elective coronary stenting, were randomly assigned to receive oral aspirin (81 mg/day) plus ticlopidine hydrochloride therapy (200 mg/day; group I) or aspirin plus cilostazol therapy (200 mg/day; group II). These medications were started at least 2 days before coronary intervention and continued until follow-up coronary angiography was performed 6 months later.

RESULTS

Subacute stent thrombosis was observed in 2 patients of group I but in no patients of group II. Major cardiac events were similarly present in both groups. Elevated transaminase levels were observed more frequently in group I than in group II (P <.05). Each of the quantitative coronary angiography variables before and immediately after coronary stenting were similar in both groups. At follow-up angiography, however, late lumen loss (0.69 +/- 0.79 mm vs 0.28 +/- 0.40 mm; P <.01) and loss index (0.42 +/- 0.56 vs 0.16 +/- 0.27; P <.01) were smaller in group II than in group I. Restenosis rate (13% vs 31%; P <.05) and target lesion revascularization rate (7% vs 21%; P <.05) were both lower in group II than in group I.

CONCLUSION

Aspirin plus cilostazol therapy may be an effective regimen for prevention of not only stent thrombosis but also restenosis.

Potential emerging therapeutic strategies to prevent restenosis in the peripheral vasculature

Despite the availability of antiplatelet and antithrombotic therapies, recent advances in catheter and stent technology and improved operator skill, restenosis remains the most frequent problem associated with percutaneous and surgical revascularization interventions for both coronary and peripheral arterial disease. Prevention of restenosis in the coronary vasculature has been demonstrated with cilostazol, trapidil, probucol, tranilast, nitric oxide donors, and clopidogrel. Given the similarities in revascularization procedures and in the pathophysiology of restenosis, it is possible that these results may be extrapolated to the setting of restenosis in the peripheral vasculature, making trials with these agents imperative. Several new agents have shown promising preliminary results for the prevention of restenosis in the peripheral vasculature, including cilostazol, low-molecular-weight heparins, and elastase. Several nonpharmacologic treatment modalities are also under study to prevent peripheral and coronary restenosis and have shown favorable initial results. These include endovascular radiation brachytherapy, arterial gene therapy, photoangioplasty, and several novel treatment delivery systems.

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.

Reduced phosphodiesterase 3 activity and phosphodiesterase 3A level in synthetic vascular smooth muscle cells: implications for use of phosphodiesterase 3 inhibitors in cardiovascular tissues

Vascular smooth muscle cells (VSMC) in situ function to control contraction and are said to express a contractile phenotype. However, during development or in response to vascular damage, VSMC proliferate and express a more synthetic phenotype. A survey of literature values for contractile and synthetic VSMC phosphodiesterase (PDE) 3 and PDE4 activities identified a marked difference in the PDE3 and PDE4 activities of these cells. In this study, a comparison of PDE3 and PDE4 activities in contractile and synthetic VSMC demonstrates that a reduced PDE3/PDE4 activity ratio in synthetic VSMC correlates with a reduced PDE3 activity and is associated with marked reductions in PDE3A mRNA and protein levels. Because we show that similar reductions in PDE3 activity and PDE3A levels occur upon culture of human aortic VSMC and that this phenomenon associates with the phenotypic switch that occurs to VSMC in response to vascular damage, our findings are presented in the context that PDE3 inhibition might be expected to selectively alter functions of contractile VSMC.

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.

Decrease in carotid intima media thickness after 1 year of cilostazol treatment in patients with type 2 diabetes mellitus

A multicenter exploratory study at three university hospitals was performed to evaluate the effect of oral cilostazol on intima media thickness (IMT) in diabetic patients. A total of 141 patients was recruited in this study and randomized into a cilostazol group and a placebo (control) group. One hundred and twenty patients completed the study (i.e. 60 on cilostazol and 60 on placebo). Biochemical profiles and the IMT of the common carotid artery (CCA) determined by high-resolution B-mode ultrasonography were measured at 0, 6, and 12 months after the oral administration of 100--200 mg of cilostazol or placebo (i.e. two or four times daily for 12 months). Clinical and biochemical characteristics, the treatment modality, and microvascular diabetic complications after randomization were not significantly different between the two groups after the study. In the cilostazol treatment group, left CCA average IMT significantly decreased from 0.94+/-0.03 to 0.91+/-0.02 mm at 6 months (P<0.05), and thereafter increased to 0.92+/-0.01 mm (P>0.05) at 12 months, whereas in the control group, it increased from 0.92+/-0.03 to 0.93+/-0.01 mm at 6 months (P>0.05), and to 0.94+/-0.01 mm at 12 months (P>0.05). As for the right CCA average IMT, it decreased from 0.83+/-0.03 to 0.82+/-0.01 mm at 6 months (P<0.05), and to 0.81+/-0.01 mm at 12 months (P<0.05) in the cilostazol group, whereas it increased from 0.87+/-0.03 to 0.89+/-0.01 mm at 6 months (P<0.05), and to 0.90+/-0.01 mm at 12 months (P<0.05) in the control group (P<0.05). After correction for risk factors such as blood pressure, smoking, and lipid profiles, there were significant changes in left and right CCA average IMT for both groups (P<0.05). Left and right CCA average IMT was significantly different between the two groups (P<0.05). After making statistical corrections for blood pressure, smoking, and lipid profiles, the differences between these two groups remained significant (P<0.05). Meanwhile, there were no differences between the groups in the change of risk factors such as BMI, blood pressure, blood sugar, HbA(1c), and lipid profiles. Generally, cilostazol was well tolerated and the most common side effect in the cilostazol group was headache (12/60), mostly early in the treatment regimen. The results suggest that oral cilostazol may be helpful in the treatment of atherosclerosis in type 2 diabetic patients, although conventional cardiovascular risk factors remained unmodified.

Comparison of ticlopidine and cilostazol for the prevention of restenosis after percutaneous transluminal coronary angioplasty

Prevention of restenosis after percutaneous transluminal coronary angioplasty (PTCA) continues to be a significant problem. Recent controlled studies have demonstrated that cilostazol suppresses restenosis after PTCA. The effects of ticlopidine, another antiplatelet agent, were compared in terms of outcomes of patients randomized for treatment with the two drugs after PTCA. A total of 35 patients (47 lesions) were assigned prospectively and randomly to ticlopidine (17 patients, 24 lesions) and cilostazol (18 patients, 23 lesions) groups. Minimal luminal diameter (MLD) and percentage of stenosis to reference diameter were estimated before PTCA, just after the procedure and after 4 months follow-up. All patients underwent 4 months angiographic follow-up, at the end of which MLD was 2.03+/-0.71 mm in the ticlopidine group and 2.05+/-0.68 mm in the cilostazol group (p = 0.95), and the percentage of stenosis to reference diameter was 31.4+/-16.7% and 30.0+/-17.0%, respectively (p = 0.78). The restenosis rate was 12.5% in the ticlopidine group and 17.4% in the cilostazol group (p = 0.69), relatively low as compared to the 20% to 30% reported in previous studies. Adverse drug reactions during the follow-up period were observed in two of the ticlopidine group and none of the cilostazol group. We conclude that both ticlopidine and cilostazol are effective for the prevention of restenosis after PTCA, however the former may be associated with slight side effects.

Antithrombotic Therapy during and after Intracoronary Stenting

Objective:

To evaluate the impact on patient outcomes of antithrombotic therapy during and after intracoronary stenting.

Data Sources:

A MEDLINE search (1966-July 2000) for English-language clinical trials and review articles using the search terms stent and coronary with one or more of the following search terms: abciximab, tirofiban, orofiban, xemilofiban, eptifibatide, aspirin, heparin, enoxaparin, tinzaparin, dalteparin, hirudin, danaparoid, dipyridamole, cilostazol, dextran, warfarin, anticoagulant, ticlopidine, and Clopidogrel. References from these articles were reviewed for additional articles. Pharmaceutical companies were contacted to identify unpublished studies. A total of 177 sources were initially identified.

Study Selection:

Studies were selected through an unblinded individual review for prospective, randomized clinical trials evaluating patient outcomes related to antithrombotic therapy during or after intracoronary stent placement. Additional human and animal studies were included for background and introductory information.

Data Extraction:

Patient characteristics in each study were compared with those of the overall stent population. The primary end point measurements were defined. The completeness of follow-up and power analysis was assessed.

Data Synthesis:

Intracoronary stenting is now a common modality for maintaining patency of occluded arteries. Antithrombotic therapy during coronary artery stent placement is changing as knowledge about the pathophysiology of thrombus formation expands and new medications become available. Development of new stent placement techniques, new stent designs, and methods of restenosis irradiation or prevention have coincided with evolving antithrombotic regimens.

Conclusions:

The current antithrombotic regimen used in coronary artery stenting is complex, but has a lower incidence of hemorrhagic complications and thrombosis compared with previous anticoagulant regimens. Antithrombotic therapy may need to be tailored to individual patient contraindications.