Long-term follow-up after extracranial internal carotid artery dissection. Prospective double-blind randomized study of the effects of four intravenous fluids on platelet function and hemostasis in elective hip surgery. [A clinical trial of using antiplatelet therapy to prevent restenosis following peripheral artery angioplasty and stenting]. Antiplatelet agents in thrombotic thrombocytopenic purpura (TTP). Results of a randomized multicenter trial by the Italian Cooperative Group for TTP. A randomized comparison of antiplatelet and anticoagulant therapy after the placement of coronary-artery stents. Safety and efficacy of the platelet glycoprotein IIb/IIIa inhibitor abciximab in Chinese patients undergoing high-risk angioplasty.
To evaluate long-term outcome after extracranial internal carotid artery dissection (eICAD) in consideration of the applied antithrombotic therapy.
                Among 33 consecutive eICAD patients initially treated either with anticoagulation (n = 25) or with antiplatelets (n = 8), a standardized interview was performed after 28 +/- 22.1 months to analyze risks and benefits of both agents. Ischemic and hemorrhagic complications, occurrence of seizure and rates of arterial recanalization were compared and long-term clinical outcome was assessed using the modified Rankin Scale (mRS) and Barthel Index (BI).
                Among anticoagulated patients, 1 died due to brain herniation. In 3 patients stroke (n = 2) or TIA (n = 1) recurred. In the antiplatelet group, none died and no subsequent ischemic events happened. Hemorrhagic complications were noted in neither treatment group. Functional outcome among anticoagulated patients was BI 92 +/- 21.6 and mRS 1.48 +/- 1.50, which did not differ from patients initially treated with antiplatelets (BI 89 +/- 18.9, mRS 1.50 +/- 1.41, p > 0.05). Four anticoagulated patients developed seizures, compared to 2 patients with antiplatelets (p > 0.05). Arterial recanalization occurred in 16 of 22 antico- agulated patients with ultrasound follow-up, compared to 6 of 6 patients with antiplatelets (p > 0.05).
                In the absence of iatrogenic side effects, both anticoagulation and antiplatelets seem to be safe for eICAD. The rates for death and stroke were low and outcome ratings did not differ between both agents. These findings may indicate that a controlled randomized trial comparing anticoagulation and antiplatelets is ethically justified.
                Copyright 2000 S. Karger AG, Basel A prospective randomized double-blind study was performed to determine the effects of three colloids, Haemaccel, Gelofusine and albumin, and also saline on platelet activation, platelet aggregation (induced by adenosine diphosphate (ADP), epinephrine, collagen) platelet agglutination by ristocetin and other hemostatic variables in 55 patients undergoing primary unilateral total hip replacement. The fluids were administered according to normal clinical practice and assessments were made immediately before, at the end, and 2 h after the end of surgery. Surgery was accompanied by thrombin generation (increases in thrombin/antithrombin III complex, prothrombin F1 +2 fragment) platelet activation (betaTG) and compromised coagulation. Generally, the platelet activation appeared to result in platelet desensitization and brought about a persistent reduction in platelet aggregation to ADP and epinephrine, irrespective of the fluid used. Additionally, Haemaccel and Gelofusine inhibited ristocetin-induced platelet agglutination and albumin inhibited collagen-induced platelet aggregation. Gross inhibitory effects of Haemaccel that had been predicted from an earlier in vitro study did not occur. Particular fluids had selective additional effects on the hemostatic system. Albumin infusion served to maintain plasma albumin at normal concentrations postsurgery. The two gelatin preparations, Haemaccel and Gelofusine, maintained plasma viscosity. All three colloids led to a transient increase in activated partial thromboplastin time postsurgery and also a transient fall in the concentration of factor VIII, which were accompanied by a transient increase in bleeding time, but there was no measurable increase in blood loss. Inhibition of platelet aggregation by certain colloids may provide additional protection against the increased thrombotic risk in patients following major surgery. To evaluate the clinical effect and restenosis rate of antiplatelet therapy following peripheral artery angioplasty and stenting.
                After successful placement of peripheral artery stents to 103 patients with peripheral arterial occlusive disease (PAOD) in were randomized assigned to 2 groups: antiplatelet therapy group receiving clopidogrel 75 mg plus aspirin 100 mg (n = 56) and control group (n = 47) receiving anticoagulation therapy low molecular weight heparin (LWMH) for 7 d plus long-term warfarin. The patients were followed up 1 day, and 1, 6, 12, and 18 months after the operation to undergo color Doppler ultrasonography, and examinations of blood routine, bleeding time, coagulation time, and ankle-brachial Index. The primary endpoint events included major bleeding rate, and composite rate of restenosis and reocclusion. The secondary endpoint events included cardiovascular events, death, and adverse drug reaction.
                There were no significant differences in the baseline data between these two groups. The thrombotic occlusion rate was 1.8% in the antiplatelet group and 0% in control group, and the restenosis rate was 14.3% in the antiplatelet group and 25.5% in control group (both P > 0.05). The bleeding complication rate of the antiplatelet group was 1.8%, significantly lower than that of the anticoagulation group (19.1%, P < 0.01). There were not significant differences in cardiovascular event rate and mortality 18 months after operation between these two groups.
                Antiplatelet therapy combined with clopidogrel plus aspirin is effective and safe in preventing restenosis following peripheral artery angioplasty and stenting. Antiplatelet agents are often included in plasma exchange-based regimens for thrombotic thrombocytopenic purpura (TTP) patients; however, the opportuneness of their use in TTP is still controversial. The italian Cooperative Group for TTP carried out a randomized trial to investigate their actual effectiveness, both in acute TTP and as maintenance treatment.
                Seventy-two TTP patients were randomized to receive plasma exchange and steroids with (group B) or without (group A) aspirin and dipyridamole. Treatment efficacy was evaluated after 15 days and salvage treatments were also considered for non-responders. Upon disease remission, the patients already treated with antiplatelet agents received ticlopidine for one year.
                Regarding the treatment of acute phase TTP, similar overall response rates were observed in the two groups (91.4% in group B vs. 75.6% in group A), but lower mortality rates were observed at 15 days in the patients treated with antiplatelet agents; as a matter of fact, 5 patients from arm A died in the first 15 days (13.5%) versus only one in arm B (2.8%). These figures, while not statistically significant, seem to suggest that antiplatelet agents might be useful in preventing deaths in acute TTP; moreover, bleeding did not worsen in antiplatelet agent-treated patients. As for the role of maintenance treatment, our results support the efficacy and safety of one-year ticlopidine therapy since the current relapse rate is significantly higher in non-treated patients; as a matter of fact, 6 patients (21.4%) in the non-ticlopidine group and only 2 (6.25%) in the ticlopidine group relapsed (P = .0182 in favor of maintenance treatment).
                Our results suggest the usefulness of antiplatelet agents in the treatment of acute phase TTP patients. Moreover, one-year ticlopidine maintenance therapy appears to be beneficial in preventing TTP relapses; however, only the completion of an adequate follow-up for all patients will definitively confirm this observation. The clinical benefit of coronary-artery stenting performed in conjunction with coronary angioplasty is limited by the risk of thrombotic occlusion of the stent as well as hemorrhagic and vascular complications of intensive anticoagulation. We compared antiplatelet therapy with conventional anticoagulant therapy with respect to clinical outcomes 30 days after coronary-artery stenting.
                After successful placement of Palmaz-Schatz coronary-artery stents, 257 patients were randomly assigned to receive antiplatelet therapy (ticlopidine plus aspirin) and 260 to receive anticoagulant therapy (intravenous heparin, phenprocoumon, and aspirin). The primary cardiac end point was a composite measure reflecting death from cardiac causes or the occurrence of myocardial infarction, aortocoronary bypass surgery, or repeat angioplasty. The primary noncardiac end point comprised death from noncardiac causes, cerebrovascular accident, severe hemorrhage, and peripheral vascular events.
                Of the patients assigned to antiplatelet therapy, 1.6 percent reached a primary cardiac end point, as did 6.2 percent of those assigned to anticoagulant therapy (relative risk, 0.25; 95 percent confidence interval, 0.06 to 0.77). With antiplatelet therapy, there was an 82 percent lower risk of myocardial infarction than in the anticoagulant-therapy group, and a 78 percent lower need for repeat interventions. Occlusion of the stented vessel occurred in 0.8 percent of the antiplatelet-therapy group and in 5.4 percent of the anticoagulant-therapy group (relative risk, 0.14; 95 percent confidence interval, 0.02 to 0.62). A primary noncardiac end point was reached by 1.2 percent of the antiplatelet-therapy group and 12.3 percent of the anticoagulant-therapy group (relative risk, 0.09; 95 percent confidence interval, 0.02 to 0.31). Hemorrhagic complications occurred only in the anticoagulant-therapy group (in 6.5 percent). An 87 percent reduction in the risk of peripheral vascular events was observed with antiplatelet therapy.
                As compared with conventional anticoagulant therapy, combined antiplatelet therapy after the placement of coronary-artery stents reduces the incidence of both cardiac events and hemorrhagic and vascular complications. Platelets are believed to play a role in the ischemic complications of coronary angioplasty, such as abrupt closure of coronary vessels during or soon after the procedure. Accordingly, we evaluated the effect of a chimeric monoclonal antibody abciximab, directed against the platelet glycoprotein IIb/IIIa receptor, in patients undergoing angioplasty who were at high risk for ischemic complications. This receptor is the final common pathway for platelet aggregation.
                In a prospective, double-blind trial, we randomly assigned 42 patients to receive a bolus and an infusion of placebo or a bolus and an infusion of abciximab. Low-dose, weight-adjusted heparin (initial dose of 70 U/kg of body weight) was used in both groups. Patients underwent coronary angioplasty for high-risk clinical situations involving unstable angina or high-risk coronary morphologic characteristics. The primary study end-point consisted of any of the following: death, nonfatal myocardial infarction, unplanned surgical revascularization, unplanned repeat percutaneous procedure, unplanned implantation of a coronary stent, or insertion of an intra-aortic balloon pump for refractory ischemia within 30 days of randomization.
                Compared with placebo, the abciximab resulted in a trend toward reduction in periprocedural myocardial infarction from 15% to 0%, although the differences were not statistically significant (p = 0.099). There were no significant differences between the two groups in the risk of major and minor bleeding and the need for blood transfusion.
                Inhibition of platelet glycoprotein IIb/IIIa receptor with abciximab, together with low-dose, weight-adjusted heparin, had a favorable trend toward the reduction of periprocedural myocardial infarction in patients undergoing high-risk angioplasty, without increasing the risk of hemorrhage.
This review shows a trend towards better outcome in patients treated with antiplatelet agents, possibly due to a reduction in secondary ischaemia. However, results were not statistically significant, thus no definite conclusions can be drawn. Also, antiplatelet agents could increase the risk of haemorrhagic complications. On the basis of the current evidence treatment with antiplatelet agents in order to prevent secondary ischaemia or poor outcome cannot be recommended.