Effects of picotamide, an antiplatelet agent, on cardiovascular, events in 438 claudicant patients with diabetes: a retrospective analysis of the ADEP study

Progress of thrombus formation and research on the structure-activity relationship for antithrombotic drugs

Many populations suffer from thrombotic disorders such as stroke, myocardial infarction, unstable angina and thromboembolic disease. Thrombus is one of the major threatening factors to human health and the prevalence of cardio-cerebrovascular diseases induced by thrombus is growing worldwide, even some persons got rare and severe blood clots after receiving the AstraZeneca COVID vaccine unexpectedly. In terms of mechanism of thrombosis, antithrombotic drugs have been divided into three categories including anticoagulants, platelet inhibitors and fibrinolytics. Nowadays, a large number of new compounds possessing antithrombotic activities are emerging in an effort to remove the inevitable drawbacks of previously approved drugs such as the high risk of bleeding, a slow onset of action and a narrow therapeutic window. In this review, we describe the causes and mechanisms of thrombus formation firstly, and then summarize these reported active compounds as potential antithrombotic candidates based on their respective mechanism, hoping to promote the development of more effective bioactive molecules for treating thrombotic disorders.

Efficacy and Safety of Antiplatelet Therapies in Symptomatic Peripheral Artery Disease: A Systematic Review and Network Meta-Analysis

BACKGROUND

Clopidogrel monotherapy is guideline-recommended in symptomatic peripheral artery disease (PAD). The advent of new antithrombotic strategies prompts an updated analysis of available evidence on antiplatelet therapy for PAD.

METHODS

We searched MEDLINE, Embase and CENTRAL through January 2019 for randomised controlled trials and observational studies comparing antiplatelet therapies as monotherapy, dual therapy, or combination with anticoagulants. Efficacy (major adverse cardiovascular events, acute or chronic limb ischaemia, vascular amputation, peripheral revascularisation) and safety (all-cause mortality and overall bleeding) outcomes were evaluated via Bayesian network meta-analyses.

RESULTS

We analysed 26 randomised controlled trials. Clopidogrel (hazard ratio, HR, 0.78; 95% credible interval [CrI] 0.65-0.93) and ticagrelor (HR 0.80; 95% CrI 0.65-0.98) significantly reduced major adverse cardiovascular events risk compared with aspirin. No significant difference was observed for dual antiplatelet therapy with clopidogrel and aspirin. Vorapaxar significantly reduced limb ischaemia and revascularisation compared with placebo, while dual antiplatelet therapy with clopidogrel and aspirin showed a trend for reduced risk of amputation compared with aspirin (risk ratio 0.68; 95% CrI 0.43-1.04). For all-cause mortality, picotamide, vorapaxar, dipyridamole with aspirin, and ticlopidine showed a significantly lower risk of all-cause mortality vs aspirin. Clopidogrel and ticagrelor showed similar overall bleeding risk vs aspirin, while dual antiplatelet therapy with clopidogrel and aspirin significantly increased bleeding risk.

CONCLUSION

This updated network meta-analysis confirms that clopidogrel significantly decreases the risk of major adverse cardiovascular events compared with aspirin, without increasing bleeding risk. Clopidogrel should remain a mainstay of PAD treatment, at least in patients at higher bleeding risk.

Role of and Recent Evidence for Antiplatelet Therapy in Prevention of Cardiovascular Disease in Diabetes

PURPOSE OF REVIEW

When treating patients with diabetes mellitus (DM), the benefits of antiplatelet therapy in preventing cardiovascular disease must be weighed against an increased risk of bleeding. Recent trials have sought to determine both the optimal anti-platelet regimen for patients with DM, and who specifically requires medication among the DM population. This paper will review recent trials and evidence recommending the use of antiplatelet therapy in the prevention of cardiovascular disease in patients with diabetes.

RECENT FINDINGS

Seven notable trials assessed the effectiveness of antiplatelet therapy in the DM population. The ASCEND trial concluded 100 mg aspirin/day reduced rates of serious vascular events (OR 0.88, p < 0.01) but also increased rates of major bleeding events (OR 1.29, p < 0.01). The DAPT study revealed a longer dual antiplatelet regimen (30 months vs. 18 months) after coronary stent placement was more effective in reducing rates of stent thrombosis (0.5% vs. 1.1%, p = 0.06) and rates of myocardial infarction (3.5% vs. 4.8%, p = 0.06). DECLARE DIABETES showed that adding cilostazol to dual antiplatelet therapy after a coronary stent procedure reduced rates of in-stent and in-segment late loss and increased rates of revascularization (p < 0.04). In PEGASUS-TIMI, daily ticagrelor demonstrated reduced rates of major adverse cardiovascular and cerebrovascular events (OR 0.84, p < 0.04). The DAVID trial compared daily picotamide with daily aspirin therapy, finding reduced mortality rates in the picotamide group (OR 0.55, p < 0.05). Lastly, ACUITY found bivalirudin monotherapy resulted in lower rates of major bleeding events when compared to a glycoprotein IIb/IIa inhibitor and heparin or bivalirudin combination regimen (p < 0.01). Dual antiplatelet therapy guidelines still typically revolve around aspirin, but an increasing number of studies have demonstrated other drugs that may have a role in preventing atherosclerotic cardiovascular disease while decreasing the risk of major bleeding. Overall, it is wise to weigh the cardiovascular risk of a DM patient before prescribing antiplatelet medication. More research is necessary to determine a universal drug or combination of drugs that is safe and effective for DM patients.

Dual roles of ynoates: desymmetrization of dicarboxylic acids using trialkylamines as alkyl equivalents

A novel method has been developed for the desymmetrization of aromatic dicarboxylic acids by employing an esterification reaction/conjugate addition of a carboxyl group to ynoates, which can trigger a coupling reaction.

Antiplatelet therapy: new pharmacological agents and changing paradigms

Recurrent atherothrombotic events in patients with acute coronary syndromes (ACS) and/or those undergoing percutaneous coronary intervention (PCI) are essentially platelet-driven processes, underscoring the need for effective pharmacological platelet inhibition. Dual antiplatelet therapy with aspirin and clopidogrel has been, for over a decade, the mainstay of antiplatelet management in ACS/PCI. However, atherothrombotic events continue to occur in a relevant proportion of subjects despite the benefit of this combination, which has led to the clinical development of newer and more potent antiplatelet drugs. Two of these, prasugrel and ticagrelor, have been recently approved for clinical use. The scope of this manuscript is to provide an up-to-date overview on new antiplatelet drugs in the setting of ACS and PCI, including the most recent advances on newly approved agents as well as on emerging compounds in clinical development.

New antithrombotic drugs: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

This article focuses on new antithrombotic drugs that are in or are entering phase 3 clinical testing. Development of these new agents was prompted by the limitations of existing antiplatelet, anticoagulant, or fibrinolytic drugs. Addressing these unmet needs, this article (1) outlines the rationale for development of new antithrombotic agents; (2) describes the new antiplatelet, anticoagulant, and fibrinolytic drugs; and (3) provides clinical perspectives on the opportunities and challenges faced by these novel agents.

Antiplatelet therapy in peripheral artery disease

Peripheral artery disease (PAD) is a term that relates to atherosclerosis and narrowing of the arteries in the lower extremities. The prevalence of PAD is approximately 12% of the adult population. Despite the low rate of peripheral complications and amputation, PAD is complicated by a high rate of cardiovascular events including myocardial infarction, stroke, and vascular death with an annual incidence of about 5%.The detection of PAD is initially based on the appearance of typical symptoms (claudication and critical limb ischemia) related to peripheral arterial insufficiency. However, PAD may also be present in the absence of clinical symptoms (asymptomatic PAD). Accordingly, asymptomatic disease may occur in up to 50% of all patients with PAD. Ankle brachial index (ABI) is a diagnostic test used to evaluate the presence of PAD, defined by an ABI ≤0.90. The ABI is also demonstrated to be useful in the assessment of vascular risk in asymptomatic and symptomatic patients. Antiplatelet therapy remains a key intervention to reduce cardiovascular risk in PAD. Data from Antithrombotic Trialists' Collaboration showed that antiplatelet treatment was associated with a 23% risk reduction of vascular events in overall population with PAD. However, closer scrutiny of these data reveals that nonaspirin antiplatelet drugs, including ticlopidine, clopidogrel, picotamide, and dipyridamole largely drove the benefits in the PAD subgroup. It remains an open issue if PAD represents an atherosclerotic clinical model where aspirin, differently from coronary heart disease, is less effective in reducing atherosclerotic progression. Based on the reported results further trials with aspirin should be done in asymptomatic (ABI ≤0.90) and symptomatic PAD patients. Finally, the role of new antiplatelet drugs such as prasugrel and ticagrelor has not yet been studied in PAD.

A critical review of antiplatelet treatment in peripheral arterial disease

Peripheral arterial disease (PAD) is a clinical setting affecting more than 5% of the population older than 60. Despite the low rate of peripheral complications and amputation, PAD is complicated by a high rate of coronary and cerebral events. For this reason, PAD is considered a marker for systemic atherosclerosis and its early diagnosis may be helpful for identifying patients at risk for cardiovascular events. During these last years, many clinical trials with antiplatelet drugs have been conducted to assess if these medications are able to influence the clinical history of PAD. This review will analyse the strengths and drawbacks of these clinical trials and their impact on clinical practice.

Preclinical evaluation of S18886 in an experimental model of coronary arterial thrombosis

The specific thromboxane receptor antagonist, S18886, was evaluated for prevention of coronary arterial thrombosis and myocardial ischemia-reperfusion in anesthetized canines. For the primary thrombosis study in left circumflex (LCX) coronary artery, 26 dogs were randomized to receive either vehicle (n = 7) or intravenous S18886 (0.3 mg/kg, n = 6; 1.0 mg/kg, n = 6; and 3.0 mg/kg, n = 7). The respective times to occlusion after S18886 were as follows: 56.8 +/- 9.3, 83.5 +/- 14.9, and 92.4 +/- 15.7 minutes compared to 43.3 +/- 8.2 minutes after vehicle. S18886 caused a minimal increase in tongue bleeding time and a significant decrease in ex vivo platelet aggregation to arachidonic acid or U46619. Another 37 dogs were randomized to receive placebo (n = 12), clopidogrel 1.0 mg/kg p.o. QDX3 (n = 9), clopidogrel + S18886 0.3 (n = 9) or 1.0 (n = 7) mg/kg intravenous. Clopidogrel produced a 50% reduction in adenosine diphosphate-induced platelet aggregation and a slight increase in the time to occlusion. However, clopidogrel + S18886 1.0 mg/kg prevented occlusive thrombus formation in most of the coronary vessels over 6 hours. S18886 did not alter myocardial infarct size in the ischemia-reperfusion model. In conclusion, S18886 alone caused a dose-dependent prolongation in the time to primary occlusive coronary artery thrombosis, whereas S18886 + clopidogrel displayed effective in preventing occlusive thrombus formation with only a moderate increase of tongue-bleeding time.

A review of picotamide in the reduction of cardiovascular events in diabetic patients

Picotamide is an antiplatelet drug with a dual inhibitory action. Thus, picotamide inhibits both thromboxane A2 (TxA2) receptors and TxA2 synthase and, at variance with aspirin, does not interfere with endothelial prostacyclin (PGI2) production. Two large randomized trials have been performed to assess the clinical efficacy of picotamide in patients at risk of atherothrombosis. The ADEP study compared peripheral artery disease (PAD) patients randomized to picotamide or placebo. This study did not show a significant reduction of cardiovascular events by picotamide but a subgroup analysis showed its potential usefulness in patients with diabetes. To investigate this issue further, the DAVID study recently enrolled diabetic patients with PAD randomized to picotamide versus aspirin; the results showed a significant reduction of overall mortality in the picotamide group. Moreover long-term picotamide treatment in diabetes promotes the reduction of microalbuminuria and the inhibition of growth of carotid plaques. These data suggest that picotamide may represent an interesting drug to be further investigated in future trials in the atherothrombotic setting.

Antithrombotic treatment for peripheral arterial disease

CONTEXT

Patients with peripheral arterial disease (PAD) bear a substantial risk for vascular events in the coronary, cerebral and peripheral circulations. In addition, this disorder is associated with a systemic milieu characterised by ongoing platelet activation and heightened thrombogenesis.

OBJECTIVE

To determine the optimal antithrombotic prophylaxis for patients with PAD.

DATA SOURCES

Using terms related to PAD and antithrombotic agents, we searched the following databases for relevant articles: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, the National Institutes of Health Clinical Trials Database, Web of Science, and the International Pharmaceutical Abstracts Database (search dates: 1 January 1990 to 1 January 2007). Additional articles were identified from cardiovascular and vascular surgery conference proceedings, bibliographies of review articles, and personal files.

STUDY SELECTION

We focused on randomised trials, systematic reviews and consensus guidelines of antithrombotic therapies for PAD.

DATA EXTRACTION

Detailed study information was abstracted by each author working independently.

RESULTS

Multiple studies show that patients with PAD manifest platelet hyperaggregability, increased levels of soluble platelet activation markers, enhanced thrombin generation and altered fibrinolytic potential. Many of these markers predict subsequent cardiovascular events. Available randomised trials and meta-analyses show that most available antithrombotic agents prevent major cardiovascular events and death in patients with PAD, including aspirin, aspirin/dipyridamole, clopidogrel, ticlopidine, picotamide and oral anticoagulants.

CONCLUSIONS

Although the most favourable risk-benefit profile, cost-effectiveness and overall evidence base supports aspirin in this setting, we provide scenarios in which alternatives to aspirin should be considered.

The induction of prostaglandin E synthase and upregulation of cyclooxygenase-2 by 9-cis retinoic acid

9-cis Retinoic acid (9cRA) is a promising lead compound to design the retinoid X receptor (RXR) ligands with the ability to simultaneously activate RXR heterodimers with the selectivity to their nuclear receptor partners. In this study, we investigated the effects of 9cRA on the prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) production. 9cRA increased the PGE2 and TXA2 productions in the presence of lipopolysaccharide (LPS). All-trans retinoic acid, the retinoic acid receptor ligand, also increased their production. We revealed that cyclooxygenase (COX)-2 was clearly induced by 9cRA in the presence of LPS. The induction was not suppressed by indomethacin, which completely inhibited the increase in the LPS-stimulated prostanoid production by 9cRA. The expression levels of the toll-like receptor 4 and CD14, which were components of the LPS receptor complex, were increased by 9cRA in the presence and absence of LPS. PGE synthase was also clearly increased by 9cRA in the presence and absence of LPS. In this study, we noted that 9cRA increased the production of PGE2 and TXA2 by the induction of COX-2 and PGE synthase in the presence of LPS. The induction of the LPS receptor complex by 9cRA is able to upregulate the induction of COX-2 by LPS.

Platelet activation in type 2 diabetes mellitus

The abnormal metabolic state that accompanies diabetes renders arteries susceptible to atherosclerosis, being capable of altering the functional properties of multiple cell types, including endothelium and platelets. In particular, an altered platelet metabolism and changes in intraplatelet signaling pathways may contribute to the pathogenesis of atherothrombotic complications of diabetes. A variety of mechanisms may be responsible for enhanced platelet aggregation. Among them, hyperglycemia may represent a causal factor for in vivo platelet activation, and may be responsible for nonenzymatic glycation of platelet glycoproteins, causing changes in their structure and conformation, as well as alterations of membrane lipid dynamics. Furthermore, hyperglycemia-induced oxidative stress is responsible for enhanced peroxidation of arachidonic acid to form biologically active isoprostanes, which represents an important biochemical link between impaired glycemic control and persistent platelet activation. Finally, increased oxidative stress is responsible for activation of transcription factors and expression of redox-sensitive genes leading to a phenotypic switch of endothelium toward an adhesive, pro-thrombotic condition, initial platelet activation, adhesion and subsequent platelet aggregate formation. All this evidence is strengthened by the results of clinical trials documenting the beneficial effects of metabolic control on platelet function, and by the finding that aspirin treatment may even be more beneficial in diabetic than in high-risk non-diabetic patients. Attention to appropriate medical management of diabetic patients will have great impact on long-term outcome in this high-risk population.

Inhibitors of platelet signal transduction as anti-aggregatory drugs

In the treatment and prevention of cardiovascular diseases, inhibition of platelet aggregation is of fundamental importance. Inhibition of platelet aggregation can be achieved by either inhibition of membrane receptors or by interception of signalling pathways. While receptor antagonism provides high specificity, the inhibition of platelet signal transduction is more effective. The effectiveness results from the inhibition of platelets, regardless of the cause of activation. These common pathway inhibitors are either intercepting platelet activating mechanisms or amplifying the action of endogenous platelet inhibitors. The physiological anti-aggregants are the endothelial factors NO and prostacyclin, which elevate intracellular cGMP or cAMP content, respectively. By administration of NO-releasing agents, prostacyclin analogues or other cyclic nucleotide elevating drugs the platelet anti-aggregatory action of endothelial factors can be effectively mimicked. Besides antiplatelet activity these drugs also act on vascular smooth muscle causing relaxation and therefore vasodilation, an additional beneficial effect. Inhibition of phosphodiesterases causes elevation of platelet cyclic nucleotide content and thus inhibits platelet aggregation and causes vasodilation. Another relevant target for anti-aggregatory treatment is the arachidonic acid metabolic pathway. This pathway can be intercepted by blockade of either cyclooxygenase-1 (COX-1) or thromboxane synthase. Inhibition of these enzymes may be further amplified by additional antagonism of the thromboxane receptor thus not only preventing formation of thromboxane but also activation of thromboxane receptor by thromboxane precursors, which were particularly effective in clinical trials. In vivo these precursors may be metabolised to prostacyclin in the endothelium and consequently provide additional platelet anti-aggregatory activity. A rather new target for platelet anti-aggregatory treatment is the ecto-nucleotidase CD-39 which limits the plasma level of nucleotides. While several of the novel anti-aggregatory drugs were disappointing in clinical studies combinations of drugs with different effector enzymes showed potent antithrombotic efficacy.

The role of platelets in diabetes-related vascular complications

The contribution of platelets to the pathogenesis and progression of vascular complications in diabetes is supported by several studies. In general, platelets obtained from diabetic subjects show increased adhesiveness and an exaggerated aggregation, both spontaneous and in response to stimulating agents. The causes for this activation are multifold: altered exposure and/or abundance of glycoprotein receptors for agonists and adhesive proteins on the platelet surface, increased binding of fibrinogen, decreased membrane fluidity, altered platelet metabolism and changes in intraplatelet signalling pathways. The altered biophysical state of platelet membrane components in diabetes mellitus may be one of the major determinants of platelet hypersensitivity and hyperfunction and may contribute to impairments in various metabolic pathways, like intensified calcium mobilisation and accentuated thromboxane synthesis and release. Activated platelets interact with other cells, such as endothelial cells and leukocytes as well with the coagulation system in the process of atherosclerosis. Some studies indicated that platelet dysfunction was especially apparent in diabetic subjects with macro- or microangiopathy, while others showed that it may be related to the presence of diabetes mellitus per se. Several pharmaceutical compounds have been developed for the inhibition of platelet activation. However, aspirin treatment is cheap and effective, and aspirin remains to be the drug of choice for diabetic patients. It should be prescribed widely for patients who are at high risk of cardiovascular events.

Issues and challenges with antithrombotic therapy in diabetic patients with acute coronary syndromes

Diabetes mellitus is associated with significant morbidity and mortality in the setting of acute coronary syndromes. This increased risk is attributable, in large part, to the derangements in coagulation that can accompany the diabetic disease state. Patients with diabetes mellitus have disturbances in endothelial function, platelet function, and coagulation factors. Until recently, there has been little direct exploration of therapeutic measures to improve outcome specifically among diabetic patients with acute coronary syndromes. Fortunately, antithrombotic therapies that have proven benefit in the general population also seem to be beneficial among patients with diabetes, although optimal dosing for improved safety and efficacy in this population has yet to be established for many of these agents. Primary prevention strategies and strict attention to risk factor modification hold the greatest promise for improving long-term outcome.

The thromboxane receptor antagonist S18886 but not aspirin inhibits atherogenesis in apo E-deficient mice: evidence that eicosanoids other than thromboxane contribute to atherosclerosis

Atherosclerosis involves a complex array of factors, including leukocyte adhesion and platelet vasoactive factors. Aspirin, which is used to prevent secondary complications of atherosclerosis, inhibits platelet production of thromboxane (Tx) A(2). The actions of TxA(2) as well as of other arachidonic acid products, such as prostaglandin (PG) H(2), PGF(2alpha), hydroxyeicosatetraenoic acids, and isoprostanes, can be effectively antagonized by blocking thromboxane (TP) receptors. The purpose of this study was to determine the role of platelet-derived TxA(2) in atherosclerotic lesion development by comparing the effects of aspirin and the TP receptor antagonist S18886. The effect of 11 weeks of treatment with aspirin (30 mg. kg(-1). d(-1)) or S18886 (5 mg. kg(-1). d(-1)) on aortic root atherosclerotic lesions, serum levels of intercellular adhesion molecule-1 (ICAM-1), and the TxA(2) metabolite TxB(2) was determined in apolipoprotein E-deficient mice at 21 weeks of age. Both treatments did not affect body or heart weight or serum cholesterol levels. Aspirin, to a greater extent than S18886, significantly decreased serum TxB(2) levels, indicating the greater efficacy of aspirin in preventing platelet synthesis of TxA(2). S18886, but not aspirin, significantly decreased aortic root lesions as well as serum ICAM-1 levels. S18886 also prevented the increased expression of ICAM-1 in cultured human endothelial cells stimulated by the TP receptor agonist U46619. These results indicate that inhibition of platelet TxA(2) synthesis with aspirin has no significant effect on atherogenesis or adhesion molecule levels. The effects of S18886 suggest that blockade of TP receptors inhibits atherosclerosis by a mechanism independent of platelet-derived TxA(2), perhaps by preventing the expression of adhesion molecules whose expression is stimulated by eicosanoids other than TxA(2).

Long-term safety and efficacy of picotamide, a dual-action antithromboxane agent, in diabetic patients with carotid atherosclerosis: a 6-year follow-up study

In a controlled, randomized, 6-year trial the safety and efficacy of picotamide, a dual-action antithromboxane agent, were assessed in 50 patients with type 2 diabetes mellitus at increased risk of thrombotic vascular events. The patients were randomized to two groups of equal size and received 900 mg picotamide daily or placebo. After phase I (double-blind; years 1 - 2), patients receiving placebo were treated, if necessary, with antiplatelet drugs (aspirin, ticlopidine) while members of the other group continued to receive 600 mg picotamide daily. In the course of the study 21 vascular events occurred: 16 in the group receiving placebo (fatal myocardial infarction, n = 7; non-fatal stroke, n = 3) and five in the group receiving drug (fatal myocardial infarction, n = 2) (P < 0.005; Fisher's exact test). One patient (placebo group) died of malignant disease. During the initial double-blind phase a total of nine vascular events was observed (six and three in the groups receiving placebo and drug, respectively). Picotamide treatment was well tolerated and no major side-effects were observed during the study periods.

The role of tobacco cessation, antiplatelet and lipid-lowering therapies in the treatment of peripheral arterial disease

Despite the widely held belief that there are no effective medical therapies for peripheral arterial disease (PAD), current data suggest that medical therapies can effectively modify the natural history of atherosclerotic lower extremity arterial occlusive disease. The ideal medical therapy would improve claudication, forestall the onset of limb-threatening events, decrease rates of invasive interventional therapies and improve long-term patient survival. These ideal outcomes might be achieved through the use of smoking cessation interventions, including behavioral and pharmacological therapy, and the administration of antiplatelet and lipid-lowering medications in patients with PAD.

Antiaggregatory effects of picotamide in long-term treatment: a 2-year, double-blind placebo-controlled trial

The ex vivo antiaggregatory activity of picotamide, a dual antithromboxane agent, was assessed to find whether it was maintained in long-term treatment. In a double-blind, placebo-controlled 2-year study, 50 type 2 diabetic patients (35 men and 15 women; mean age 66 +/- 5 years) were enrolled and randomly given picotamide, 300 mg t.i.d. or the corresponding placebo. Platelet aggregation studies were performed at baseline and after 1, 3, 6, 12, 18 and 24 months. Compliance to the treatment was assessed by pill count at each visit. Forty-nine patients concluded the study. Starting from month 1, compared with placebo, picotamide-treated patients showed a significant inhibition of agonist-induced (ADP, arachidonic acid and collagen) platelet aggregation (-41%). The antiaggregatory effect was maintained throughout the study. At month 24, in the picotamide group, platelet aggregation was significantly lower compared with placebo (-30%). After 24 months of treatment, 20 out of 23 (86%) picotamide-treated patients showed a significant inhibition of platelet aggregation, whereas the remaining three patients had a normal platelet response. During the study, 12 patients suffered from thrombotic events of death: nine in the placebo group and three in the picotamide group, respectively. It was concluded that picotamide maintains its antiaggregatory effect, in long-term treatment, in more than 85% of patients.