Comparative Inhibitory Effects of Cilostazol and Ticlopidine on Subacute Stent Thrombosis and Platelet Function in Acute Myocardial Infarction Patients With Percutaneous Coronary Intervention

We compared the effects of ticlopidine and cilostazol on the prevention of subacute stent thrombosis (SAT) in acute myocardial infarction (AMI) patients with stenting. We also analyzed the cause of the difference by measuring platelet aggregation activity. Consecutive patients who underwent successful stenting for AMI between March 2001 and March 2004 were analyzed. In addition to aspirin (100 mg/day), cilostazol (200 mg/day) was administered to 99 cases between March 2001 and May 2002 and ticlopidine (200 mg/day) was administered to 85 cases between June 2002 and February 2004. The incidence of SAT within four weeks after stenting was analyzed. Thirty-eight AMI patients were randomized and their platelet aggregation activity was measured using a laser-scattered aggregometer (18 cases in the cilostazol group and 20 cases in the ticlopidine group). SAT did not occur in the ticlopidine group while 5 cases (5.1%) of SAT occurred in the cilostazol group (P < 0.05). The inhibitory activity of cilostazol for ADP-induced platelet aggregation was lower than that of ticlopidine (P < 0.05). Cilostazol with aspirin after stenting in AMI patients showed more frequent SAT than ticlopidine with aspirin. One of the causes for this difference was speculated to be the weaker inhibitory activity of cilostazol for ADP-induced platelet aggregation.

Preventive Strategies for Aspiration Pneumonia in Elderly Disabled Persons

Pneumonia is the fourth leading cause of death despite the availability of potent new antimicrobials in Japan. Aspiration of oropharyngeal bacterial pathogens to the lower respiratory tract is one of the most important risk factors for pneumonia. Impairments in swallowing and cough reflexes among disabled older persons, e.g., related to cerebrovascular disease, increase the risk of pneumonia. Thus, strategies to reduce the volumes and pathogenicity of aspirated material should be pursued. Since both swallowing and cough reflexes are mediated by endogenous substance P contained in the vagal and glossopharyngeal nerves, pharmacologic therapy using angiotensin-converting enzyme inhibitors, which decrease substance P catabolism, can improve both reflexes and result in the lowering of the risk of pneumonia. Similarly, since the production of substance P is regulated by dopaminergic neurons in the cerebral basal ganglia, treatment with dopamine analogs or potentiating drugs such as amantadine can reduce the incidence of pneumonia. Furthermore, since mortality from infections correlates with cutaneous anergy, interventions that reverse these age-associated changes in the immune system are also effective. The main theme of this review is to discuss how pneumonia develops in disabled older people and to suggest preventive strategies that may reduce the incidence of pneumonia among these subjects.

Antiplatelet and Antithrombotic Activity of Cilostazol is Potentiated by Dipyridamole in Rabbits and Dissociated from Bleeding Time Prolongation

PURPOSE

To determine the antiplatelet effect of cilostazol (Pletal) and its interaction with dipyridamole in in vitro and in vivo rabbit models, and to see if it can be dissociated from bleeding time prolongation.

METHODS

In vitro collagen-induced platelet aggregation was measured by an impedance-based aggregometer. The in vivo antithrombotic effect was evaluated in a rabbit carotid artery cyclic flow reduction (CFR) model, in which repetitive thrombosis was induced by mechanical injuries of the artery and stenosis. Template bleeding time was determined in rabbit ear arterioles and hindlimb nail cuticles.

RESULTS

In vitro platelet aggregation was slightly inhibited by 4 microM cilostazol (22 +/- 6%), and modestly by 13 microM (57 +/- 3% of aggregation). While dipyridamole itself up to 13 microM had no significant inhibition, it potentiated the effect from cilostazol: in the presence of 4 microM dipyridamole, 4 microM cilostazol inhibited aggregation by 47 +/- 6%. Dipyridamole also potentiated the CFR reducing effect of cilostazol: combination of dipyridamole (no effect by itself) and cilostazol at 1 microM decreased CFRs to levels achieved by 3-4 microM cilostazol alone. Bleeding times were similar in controls and animals treated with cilostazol, or with cilostazol and dipyridamole. In contrast, aspirin (4 mg/kg), while reducing CFRs, significantly increased bleeding time.

CONCLUSION

These results suggest that dipyridamole potentiates the antiplatelet effect of cilostazol without prolongation of the bleeding time, implying a potential novel combination antithrombotic therapy.

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.

Platelet activation markers, microparticles and soluble adhesion molecules are elevated in patients with arteriosclerosis obliterans: therapeutic effects by cilostazol and potentiation by dipyridamole

We evaluated the plasma concentrations of platelet activation markers, microparticles and soluble adhesion molecules in patients with arteriosclerosis obliterans (ASO) and compared the beneficial effects of cilostazol alone and combination therapy of cilostazol and dipyridamole in these patients. There was a significant elevation of CD62P, CD63, PAC-1, annexin V, platelet-derived microparticles (PDMPs), sP-selectin, sE-selectin, sICAM-1 and sVCAM-1 in the ASO patients compared with the controls. Platelet aggregation was decreased by 2 weeks of cilostazol monotherapy in the ASO patients. Adding dipyridamole to the cilostazol therapy for 2 weeks further reduced platelet aggregation. While treatment with cilostazol alone reduced levels of CD62P, CD63, PAC-1, annexin V, PDMP, and sP-selectin, the combination therapy reduced these parameters further. While sE-selectin and cell adhesion molecules did not change significantly after 2 weeks of combination therapy, they exhibited a remarkable decrease after 16 weeks of combination treatment. These findings suggest that platelets are activated in ASO patients, and cilostazol is effective to reduce platelet activation. Furthermore, dipyridamole may potentiate the beneficial effect of cilostazol in ASO patients. Combination use of both drugs may help to prevent the onset of cardiovascular complications in patients with ASO by activated platelets and PDMP.

Comparison of cilostazol and ticlopidine for one-month effectiveness and safety after elective coronary stenting

PURPOSE

To compare the oral antiplatelets, phosphodiesterase III inhibitor cilostazol and the thienopyridine ticlopidine, for one-month effectiveness and safety as an adjunctive therapy after coronary stenting.

METHODS

Published studies retrieved through Medline and other databases from 1966-2002. Meta-analyses evaluated effectiveness and adverse side effects for one-month administrations of aspirin plus cilostazol or aspirin plus ticlopidine therapy after coronary stenting. Major adverse cardiac events (MACE), stent-associated thrombosis or adverse side effects after coronary stenting were compared between the two study arms and expressed with the odds ratios (OR) specific for the individual studies and meta-analytic summary for OR.

RESULTS

Five clinical studies met the inclusion criteria, and 4 of these studies underwent meta-analysis. With regard to the comparison of the OR summary for MACE and stent-associated thrombosis for the clinical outcome, there were no statistical significant differences between aspirin plus cilostazol and aspirin plus ticlopidine. While, the incidence of adverse side effects tended to be lower, they were not statistically significant in patients with aspirin plus cilostazol.

CONCLUSIONS

Our meta-analysis results indicated that there were no differences between cilostazol (plus aspirin) and ticlopidine (plus aspirin) with regard to effectiveness and safety for a one-month period when used as an adjunctive therapy after coronary stenting.

The phosphodiesterase 3 inhibitor cilostazol dilates large cerebral arteries in humans without affecting regional cerebral blood flow

Cilostazol, an inhibitor of phosphodiesterase (PDE) type 3, is used clinically in peripheral artery disease. PDE3 inhibitors may be clinically useful in the treatment of delayed cerebral vasospasm after subarachnoid hemorrhage. The authors present the first results on the effect of cilostazol on cerebral hemodynamics in normal participants. In this double-blind, randomized, crossover study, 200 mg cilostazol or placebo was administered orally to 12 healthy participants. Cerebral blood flow was measured using 133Xe inhalation and single photon emission computerized tomography. Mean flow velocity in the middle cerebral arteries (VMCA) was measured with transcranial Doppler, and the superficial temporal and radial arteries diameters were measured with ultrasonography. During the 4-hour observation period, there was no effect on systolic blood pressure (P = 0.28), but diastolic blood pressure decreased slightly compared with placebo (P = 0.04). VMCA decreased 21.5 +/- 5.7% after cilostazol and 5.5 +/- 12.2% after placebo (P = 0.02, vs. placebo), without any change in global or regional cerebral blood flow. The superficial temporal artery diameter increased 17.6 +/- 12.3% (P < 0.001 vs. baseline) and radial artery diameter increased 12.6 +/- 8.6% (P < 0.001 vs. baseline). Adverse events, especially headache, were common. The findings suggest that cilostazol is an interesting candidate for future clinical trials of delayed cerebral vasospasm.

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

BACKGROUND

A recent study has shown that triple anti-platelet therapy (cilostazol+clopidogrel+aspirin) resulted in a significantly lower restenosis rate after coronary stenting than did conventional therapy (clopidogrel+aspirin). However, the anti-platelet effects of cilostazol, when combined with clopidogrel and aspirin, have not been evaluated.

METHODS

Low dose cilostazol (50 mg/BID) was given to 47 patients who had already been taking clopidogrel (75 mg/day) and aspirin (100 mg/day) for more than 1 month subsequent to coronary stenting due to AMI and unstable angina. Markers of platelet activation, P-selectin and activated GPIIb/IIIa on platelets, were measured at baseline and 2 weeks after cilostazol treatment. We empirically divided patients into tertiles (low, n =16; moderate, n = 14; high group, n = 17), according to the baseline P-selectin expression. We then performed a comparative assessment of the anti-platelet effects of cilostazol at baseline and after 2 weeks of cilosatzol administration.

RESULTS

P-selectin was significantly decreased after 2 weeks of cilostazol treatment in total patients (n = 47, 3.2 +/- 2.4% to 2.0 +/- 1.9%, p = 0.03). This inhibition of P-selectin expression was mainly achieved in the moderate and high P-selectin groups (low group; 1.4 +/- 0.5 to 1.9 +/- 1.3%, p > 0.05, moderate group; 2.5 +/- 0.3 to 1.3 +/- 0.3%, p < 0.05, high group; 5.4 +/- 2.7 to 2.7 +/- 2.8%, p < 0.05). Activated GPIIb/IIIa was not significantly changed (13.5% to 17.6%, p > 0.05). Underying disease, cardiovascular risk factors, concomitant medication including statin, and hsCRP were not related to the degree of P-selectin expression.

CONCLUSION

Our data demonstrated that cilostazol treatment in addition to conventional anti-platelet therapy provides more effective suppression of platelet P-selectin expression in patients with relatively high platelet activity.

Effect of cilostazol, a phosphodiesterase inhibitor, on carotid IMT in Japanese type 2 diabetic patients

The aim of this study was to investigate the effect of cilostazol, a cAMP phosphodiesterase inhibitor, on carotid artery intima-media thickness (IMT) and on the incidence of cardiovascular events in Japanese subjects with type 2 diabetes. A total of 62 type 2 diabetic subjects were allocated equally to the cilostazol treatment group (n = 31) and the control group (n = 31). Carotid IMT was evaluated before and after treatment using B-mode ultrasonography. After the study period (mean +/- SD: 2.6 +/- 0.17 years), carotid IMT showed a significantly greater increase in the control group than in the cilostazol group (0.12 +/- 0.14 mm vs. 0.04 +/- 0.02 mm, p < 0.05). In the control group, 1 out of 31 patients suffered from symptomatic cerebral infarction and 1 had angina pectoris during the observation period. On the other hand, no subject in the cilostazol group developed cardiovascular events during the study period. At baseline, the diabetic patients given cilostazol had a significantly lower HbA1c level than the control subjects, but the other atherosclerotic risk factors (BMI, blood pressure, and serum lipids) and the duration of diabetes did not differ between the two groups. These results indicate that cilostazol therapy can attenuate the increase of carotid artery IMT in Japanese subjects with type 2 diabetes.

Cilostazol Prevents Remnant Lipoprotein Particle-Induced Monocyte Adhesion to Endothelial Cells by Suppression of Adhesion Molecules and Monocyte Chemoattractant Protein-1 Expression via Lectin-Like Receptor for Oxidized Low-Density Lipoprotein Receptor Activation

This study shows cilostazol effect to prevent remnant lipoprotein particle (RLP)-induced monocyte adhesion to human umbilical vein endothelial cells (HUVECs). Upon incubation of HUVECs with RLP (50 microg/ml), adherent monocytes significantly increased by 3.3-fold with increased cell surface expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1, E-selectin, and monocyte chemoattractant protein-1 (MCP-1). Cilostazol ( approximately 1-100 microM) concentration dependently repressed these variables as did (E)3-[(4-t-butylphenyl)sulfonyl]-2-propenenitrile (BAY 11-7085) (10 microM), a specific nuclear factor-kappaB (NF-kappaB) inhibitor. Cilostazol effects were significantly antagonized by iberiotoxin (1 microM), a maxi-K channel blocker. RLP significantly increased expression of lectin-like receptor for oxidized low-density lipoprotein (LDL) (LOX-1) receptor protein. Upon transfection with antisense LOX-1 oligodeoxynucleotide (As-LOX-1), LOX-1 receptor expression was reduced, whereas HUVECs with sense LOX-1 oligodeoxynucleotide did express high LOX-1 receptor. RLP-stimulated superoxide and tumor necrosis factor-alpha levels were significantly lowered with decreased expression of VCAM-1 and MCP-1 by transfection with As-LOX-1 as did polyinosinic acid (10 microg/ml, a LOX-1 receptor inhibitor). RLP significantly degraded inhibitory kappaBalpha in the cytoplasm and activated nuclear factor-kappaB (NF-kappaB) p65 in the nucleus of HUVECs with increased luciferase activity of NF-kappaB, all of which were reversed by cilostazol (10 microM), BAY 11-7085, and polyinosinic acid. Together, cilostazol suppresses RLP-stimulated increased monocyte adhesion to HUVECs by suppression of LOX-1 receptor-coupled NF-kappaB-dependent nuclear transcription via mediation of the maxi-K channel opening.

Cilostazol, a phosphodiesterase inhibitor, reduces microalbuminuria in the insulin-resistant Otsuka Long-Evans Tokushima Fatty rat

We evaluated association between hyperinsulinemia/insulin resistance and microalbuminuria in the insulin-resistant Otsuka Long-Evans Tokushima Fatty (OLETF) rat. OLETF rats showed glomerular hyperfiltration (an increase in creatinine clearance and a decrease in fractional excretion of Na) and microalbuminuria at the insulin-resistant prediabetic stage, and both were related to expression of transforming growth factor (TGF)-beta(1) and extracellular matrix protein such as fibronectin and collagen (a(1)) IV. Cilostazol, a selective type III cyclic nucleotide phosphodiesterase (PDE) inhibitor, normalized glomerular hyperfiltration and microalbuminuria with a parallel decline of TGF-beta(1) and extracellular matrix protein mRNA expression. Cilostazol may be beneficial to lessen early glomerular nephropathy in a state of hyperinsulinemia/insulin resistance.

Locally applied cilostazol suppresses neointimal hyperplasia by inhibiting tenascin-C synthesis and smooth muscle cell proliferation in free artery grafts

OBJECTIVE

Accumulation of smooth muscle cells and extracellular matrix in the intima of artery bypass grafts induces neointimal hyperplasia, resulting in graft failure. We investigated the inhibitory effect of locally applied cilostazol, an inhibitor of cyclic adenosine monophosphate phosphodiesterase III, on neointimal hyperplasia and the role of tenascin-C synthesis and smooth muscle cell proliferation in free artery grafts. Methods and results We established a distal anastomotic stricture model of free artery graft stenosis using rat abdominal aorta. In this model, neointimal hyperplasia was observed not only in the distal anastomotic site but also in the graft body at postoperative day 14 and was markedly progressed at day 28. Strong expression of tenascin-C was found in the media and neointima of the graft body. When cilostazol was locally administered around the graft using Pluronic gel, neointimal hyperplasia of the graft was significantly suppressed in comparison with gel-treated control graft. The mean neointima/media area ratio was reduced by 86.6% for the graft body and by 75.8% for the distal anastomotic site versus the control. Cilostazol treatment decreased cell proliferation and tenascin-C expression in the neointima. In an in vitro experiment using cultured smooth muscle cells isolated from rat aorta, cilostazol completely suppressed the tenascin-C mRNA expression induced by platelet-derived growth factor-BB.

CONCLUSION

A single topical administration of cilostazol may suppress neointimal hyperplasia by inhibiting cell proliferation and tenascin-C synthesis in free artery grafts, presenting the potential for clinical use in vascular surgery.

Recovery of platelet function after withdrawal of cilostazol administered orally for a long period

To clarify the recovery of platelet function after abrupt withdrawal of cilostazol, we studied platelet function and cilostazol concentration in elderly who received cilostazol, 100 mg twice a day (200 mg/day), for a long period. After interviewing the time of final cilostazol intake, platelet aggregability was determined with an aggregometer using four different concentrations of adenosine-5'-diphosphate as an inducer, which showed the grading curve (GC) type and platetet aggregatory threshold index (PATI). Serum cilostazol concentration was also determined by high-performance liquid chromatography. The GC type and PATI showed suppressed platelet function until 15 hours after withdrawal in half of patients. Bleeding time measured by the Simplate method was prolonged within 4 hours, but recovered by 12 hours after the withdrawal. Some serum cilostazol concentrations were still high 15 hours after withdrawal, while platelets were inhibited even in patients with low serum concentration of cilostazol. In the group receiving the drug for less than 6 months, PATI correlated with serum cilostazol concentration, but platelets in the long-term administration group (more than 48 months) were suppressed at the low serum cilostazol concentration. These findings indicated that platelet function recovered within 12-16 hours after withdrawal in these patients.

The role of cilostazol in the treatment of intermittent claudication

This paper represents a review, by experts, of current opinion and information on intermittent claudication (IC) and the role that cilostazol plays in its treatment. IC is a common and debilitating condition that has a significant adverse impact on health-related quality of life (HR-QoL). It is currently under-recognised as a powerful marker of increased cardiovascular (CV) risk. The clinical priority is secondary prevention -- sometimes referred to as best medical therapy aimed at reducing CV risk. However, the priority for most patients (often overlooked by clinicians) is symptom relief: an increase in walking distance leading to an improvement in HR-QoL. The symptoms of IC may be improved by exercise, pharmacotherapy, and when these are unsuitable or unsuccessful, endovascular or surgical intervention. Cilostazol is indicated for the improvement of maximal and pain-free walking distance in patients with IC who do not have rest pain or tissue necrosis. In clinical trials, cilostazol improved symptoms both objectively and subjectively, and also improved HR-QoL. Cilostazol is usually well tolerated, with adverse events being generally mild to moderate in intensity, and transient or resolved after symptomatic treatment (e.g. non-prescription analgesics). Such events only infrequently require permanent drug withdrawal. There are no interactions with other drugs commonly prescribed in patients with IC, such as statins and anti-platelet agents. Cilostazol also has a range of potentially beneficial effects that may in the future be proven to decrease CV risk and modify the underlying process of atherosclerosis. Cilostazol represents the best evidence-based pharmacological therapy available for the symptoms of IC and should be the first-line treatment for symptom improvement in appropriate patients. Based on the available treatment strategies, the paper presents a suggested algorithm for the management of IC highlighting the role of cilostazol.

Chronotropic Effect of the Antithrombotic Agent Cilostazol in a Patient with Sick Sinus Syndrome and Syncope

In this case report we describe an 80-year-old man with sick sinus syndrome (SSS) who developed syncope attacks. The diagnosis of SSS was based on electrocardiographic evidence of markedly prolonged sinus arrests associated with syncope attacks while in hospital. The patient was given cilostazol, an anti-thrombotic agent that selectively inhibits cyclic nucleotide phosphodiesterase type 3, at a dose of 100 mg twice daily. The syncope attacks ceased, and an electrocardiogram obtained 1 week after the start of cilostazol administration showed no evidence of sinus arrest. The outcome of this case suggests that cilostazol may be useful in patients with syncope attacks due to SSS, although the long-term chronotropic effects of cilostazol need to be evaluated.

Cilostazol inhibits high glucose-mediated endothelial-neutrophil adhesion by decreasing adhesion molecule expression via NO production

OBJECTIVE

Endothelial-neutrophil adhesion is crucial for vascular injury, the major cause of diabetic vascular complications. On the other hand, platelet aggregation inhibitors, frequently used for diabetic patients with intermittent claudication, have been shown to decrease the incidence of atherosclerosis-mediated diseases (acute myocardial infarction and stroke). However, whether these agents act directly on the endothelial reactions to hyperglycemia remains unclear. Therefore, we examined their direct effects on endothelial-neutrophil adhesion and expression of endothelial adhesion molecules induced by high glucose.

METHODS AND RESULTS

After human endothelial cells were cultured in high glucose medium, neutrophils from healthy volunteers were added and allowed to adhere for 30 min. Adhered neutrophils were quantified by measuring their myeloperoxidase (MPO) activities, and surface expression of endothelial adhesion molecules was determined with an enzyme immunoassay. Of the platelet aggregation inhibitors tested, only cilostazol significantly attenuated the adhesion through decreasing expression of intercellular adhesion molecule-1 (ICAM-1) and P-selectin. In addition, nitric oxide (NO) synthase inhibitors reduced the inhibitory effects of cilostazol, but a protein kinase C (PKC) activator did not.

CONCLUSIONS

Cilostazol may act directly on endothelial cells to inhibit expression of adhesion molecules and neutrophil adhesion induced by high glucose through increasing NO production.

Antithrombotic Therapy in Peripheral Arterial Occlusive Disease

This chapter about antithrombotic therapy for peripheral arterial occlusive disease is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004;126:179S-187S). Among the key recommendations in this chapter are the following: For patients with chronic limb ischemia, we recommend lifelong aspirin therapy in comparison to no antiplatelet therapy in patients with clinically manifest coronary or cerebrovascular disease (Grade 1A) and in those without clinically manifest coronary or cerebrovascular disease (Grade 1C+). We recommend clopidogrel over no antiplatelet therapy (Grade 1C+) but suggest that aspirin be used instead of clopidogrel (Grade 2A). For patients with disabling intermittent claudication who do not respond to conservative measures and who are not candidates for surgical or catheter-based intervention, we suggest cilostazol (Grade 2A). We suggest that clinicians not use cilostazol in patients with less-disabling claudication (Grade 2A). In these patients, we recommend against the use of pentoxifylline (Grade 1B). We suggest clinicians not use prostaglandins (Grade 2B). In patients with intermittent claudication, we recommend against the use of anticoagulants (Grade 1A). In patients with acute arterial emboli or thrombosis, we recommend treatment with immediate systemic anticoagulation with unfractionated heparin (UFH) [Grade 1C]. We also recommend systemic anticoagulation with UFH followed by long-term vitamin K antagonist (VKA) in patients with embolism [Grade 1C]). For patients undergoing major vascular reconstructive procedures, we recommend UFH at the time of application of vascular cross-clamps (Grade 1A). In patients undergoing prosthetic infrainguinal bypass, we recommend aspirin (Grade 1A). In patients undergoing infrainguinal femoropopliteal or distal vein bypass, we suggest that clinicians do not routinely use a VKA (Grade 2A). For routine patients undergoing infrainguinal bypass without special risk factors for occlusion, we recommend against VKA plus aspirin (Grade 1A). For those at high risk of bypass occlusion and limb loss, we suggest VKA plus aspirin (Grade 2B). In patients undergoing carotid endarterectomy, we recommend aspirin preoperatively and continued indefinitely (Grade 1A). In nonoperative patients with asymptomatic or recurrent carotid stenosis, we recommend lifelong aspirin (Grade 1C+). For all patients undergoing extremity balloon angioplasty, we recommend long-term aspirin (Grade 1C+).

Reduction of remnant lipoprotein cholesterol concentrations by cilostazol in patients with intermittent claudication

BACKGROUND

Elevated triglyceride-rich lipoproteins and reduced high-density lipoproteins (HDL) are associated with the development of intermittent claudication (IC), a life-limiting symptom of peripheral arterial disease. Cilostazol, a potent platelet inhibitor and vasodilator, lowers triglycerides and increases HDL concentrations in addition to increasing walking distance in patients with intermittent claudication. However, the association of remnant lipoproteins (a more atherogenic subset of triglyceride-rich lipoproteins) and peripheral arterial disease and the effects of cilostazol on remnant lipoproteins have not been studied.

METHODS AND RESULTS

We quantified plasma remnant lipoprotein concentrations using the remnant lipoprotein-cholesterol assay (RLP-C). Patients with intermittent claudication (n = 415) had significantly higher remnant lipoprotein concentrations compared to reference subjects (n = 874; 0.31 +/- 0.32 versus 0.24 +/- 0.17 mmol/l, P < 0.001) in addition to elevated total triglyceride (2.67 +/- 1.92 versus 1.92 +/- 1.24 mmol/l, P < 0.001) and reduced high-density lipoprotein (HDL) cholesterol concentrations (1.06 +/- 0.31 versus 1.22 +/- 0.36 mmol/l, P < 0.001). Cilostazol treatment (100 mg, b.i.d.) in patients with intermittent claudication (n = 56) for 6 months resulted in 20% reduction of remnant lipoprotein-cholesterol (from 0.27 +/- 0.21 to 0.22 +/- 0.09 mmol/l, P < 0.05) versus no significant change (from 0.26 +/- 0.17 to 0.27 +/- 0.12 mmol/l) in the placebo group (n = 67). Cilostazol also reduced triglyceride concentrations significantly (from 2.32+/-1.46 to 1.79+/-0.72 mmol/l, P < 0.01, in the cilostazol group versus 2.38 +/- 1.39 to 2.25 +/- 1.19 mmol/l in the placebo group) and increased HDL cholesterol concentrations (from 1.06 +/- 0.23 to 1.24 +/- 0.34 mmol/l, P < 0.001) in the cilostazol group versus no significant change (1.06 +/- 0.34 to 1.09 +/- 0.36 mmol/l) in the placebo group. Pentoxifylline (400 mg, t.i.d.) did not have any significant effects on lipid variables (n = 66).

CONCLUSIONS

Remnant lipoprotein concentrations are significantly elevated in patients with intermittent claudication and can be reduced by cilostazol. Reduction of remnant lipoproteins may provide a long-term benefit to the patients with symptomatic peripheral arterial disease.

Early statin treatment in patients with acute coronary syndrome: demonstration of the beneficial effect on atherosclerotic lesions by serial volumetric intravascular ultrasound analysis during half a year after coronary event: the ESTABLISH Study

BACKGROUND

Recent clinical trials have demonstrated that aggressive lipid lowering by statins could prevent recurrent events after acute coronary syndrome (ACS). We hypothesized that this efficacy was caused by a significant reduction in plaque volume by aggressive LDL cholesterol (LCL-C) lowering. The present study investigated the effect of early statin treatment on plaque volume of a nonculprit lesion by serial volumetric intravascular ultrasound in patients with ACS.

METHODS AND RESULTS

Seventy patients with ACS were enrolled. All patients underwent emergency coronary angiography and percutaneous coronary intervention (PCI). They were randomized to intensive lipid-lowering therapy (n=35; atorvastatin 20 mg/d) or control (n=35) groups after PCI. Volumetric intravascular ultrasound analyses were performed at baseline and 6-month follow-up for a non-PCI site in 48 patients (atorvastatin, n=24; control, n=24). LDL-C level was significantly decreased by 41.7% in the atorvastatin group compared with the control group, in which LDL-C was increased by 0.7% (P<0.0001). Plaque volume was significantly reduced in the atorvastatin group (13.1+/-12.8% decrease) compared with the control group (8.7+/-14.9% increase; P<0.0001). Percent change in plaque volume showed a significant positive correlation with follow-up LDL-C level (R=0.456, P=0.0011) and percent LDL-C reduction (R=0.612, P<0.0001), even in patients with baseline LDL-C <125 mg/dL.

CONCLUSIONS

Early aggressive lipid-lowering therapy by atorvastatin for 6 months significantly reduced the plaque volume in patients with ACS. Percent change in plaque volume showed a significant positive correlation with percent LDL-C reduction, even in patients with low baseline LDL-C.

The influence of platelets on the promotion of invasion by tumor cells and inhibition by antiplatelet agents

OBJECTIVE

Using a chemoinvasion assay, we show that platelets promote invasiveness of 5 pancreatic adenocarcinoma cell lines.

METHODS

Gelatin zymography and Western blot analysis were performed to detect metalloproteinase-9 (MMP-9) secreted from tumor cells in the presence or absence of platelets. The effects of antiplatelet agents on the invasiveness of tumor cells and the secretion level of MMP-9 were evaluated.

RESULTS

The number of traversed tumor cells significantly increased when incubated with platelets compared without platelets in all cell lines. The MMP-9 band was detected in all tumor cell lines, and the intensity was obviously greater in conditions of incubation with platelets than without. In the experiment of antiplatelet agents effects, it was confirmed that invasiveness of tumor cells significantly decreased following incubation with cilostazol depending on the concentration in spite of the presence of platelets. The level of MMP-9 also significantly decreased in the ELISA analysis.

CONCLUSIONS

These data mean platelets activate invasiveness of tumor cells because of enhanced MMP-9 secretion. Furthermore, anti-platelet drugs may inhibit invasiveness of tumor cells due to decreased MMP-9 secretion, and this inhibition may lead to the suppression of tumor cell invasion. We propose that antiplatelet agents are applicable in clinical treatment to inhibit metastasis of malignant tumor cells.

Treatment of intermittent claudication: cilostazol

Intermittent claudication is a potentially disabling disorder that impairs quality of life and is a marker of underlying cardiovascular disease. Treatment involves secondary prevention and measures to improve walking. Cilostazol significantly increases walking distance and quality of life in claudicants.

[Effect of cilostazol on transient outward potassium current in human atrial myocytes]

AIM

To investigate the effect of cilostazol on transient outward potassium current (I(to1) in isolated human atrial myocytes.

METHODS

Atrial tissue samples were obtained from hearts of 15 patients ranging from 5 to 65 years of age (36.0 +/- 23.9 years). I(to1) was recorded by using the whole-cell patch clamp technique in enzymatically isolated atrial myocytes.

RESULTS

Cilostazol at 30 micromol/ L significantly decreased I(to1) at the test potential of +50 mV. The peak amplitude of I(to1) was decreased from (8.16 +/- 0.70) pA/pF to (4.84 +/- 0.60) pA/pF (P < 0.01). In addition, the drug inhibited the current in a concentration-dependent manner (IC50 = 13.18 +/- 2.60 micromol/L). The significantly inhibitive effect was observed from the concentration of 1 micromol/L, and the maximal effect was 51.09% +/- 3.0% at 50 micromol/L. Furthermore, voltage-dependence of activation and inactivation, and time-dependent recovery from inactivation of I(to1) were not altered by cilostazol.

CONCLUSION

The results indicates that cilostazol inhibits I(to1) in human atrial myocytes.