Long-term Follow-up Of Dual Antiplatelet Therapy With Aspirin And Low-dose Clopidogrel In Patients Undergoing Percutaneous Coronary Intervention

Objective:A retrospective study to assess the efficacy and safty of co-administration of aspirin and low-dose clopidogrel in patients undergoing percutaneous coronary intervention (PCI) after one year.Methods:From March2004to September2013, the patients with successful drug-eluting stents implantation after one year were selected. Method one:a total of3366patients were divided into treatment group (aspirin combined with low-dose clopidogrel, n=1682) and control group (aspirin alone, n=1684) in chronological order. In the initial admission, two groups of patients were routinely given loading dose of aspirin300mg per day, and this dose was continued to a month after undergoing percutaneous coronary intervention. Then long-term use of aspirin (100mg/d) was given. At the same time,300mg or600mg-loading dose of clopidogrel was used and then continued to take maintenance dose (75mg/d) at least12months. After12months, aspirin (100mg/d) was continued taking, while taking clopidogrel25mg/d in aspirin combined with low-dose clopidogrel group (treatment group) and only taking aspirin100mg/d in aspirin alone group (control group). In accordance with indications and the principle of individuation, two groups of patients could be combined to give statin lipid-lowering drugs, beta blockers, calcium antagonists, nitrates drugs, angiotensin converting enzyme inhibitors and angiotensinreceptor antagonists, as well as other drugs. The average follow-up period was29.6+16.5months. The major adverse cardiovascular and cerebrovascular events (cardiac death, nonfatal myocardial infarction, stroke, target vessel revascularization, total deaths, recurrent angina, and stent thrombosis formation) and clinical complications (bleeding events and cytopenia) were evaluated. Method two:a total of1110patients were divided into group A (aspirin100mg/d combined with clopidogrel25mg/d, n=413), group B (aspirin100mg/d combined with clopidogrel50mg/d, n=245), and group C (aspirin100mg/d combined with clopidogrel75mg/d, n=452). In accordance with indications and the principle of individuation, two groups of patients could be combined to give statin lipid-lowering drugs, beta blockers, calcium antagonists, nitrates drugs, angiotensin converting enzyme inhibitors and angiotensinreceptor antagonists, as well as other drugs. The average follow-up period was24.01±12.83months. The major adverse cardiovascular and cerebrovascular events (cardiac death, nonfatal myocardial infarction, stroke, target vessel revascularization, total deaths, recurrent angina, and stent thrombosis formation) and clinical complications (bleeding events and cytopenia, and so on) were evaluated.Results:One:Rates of cardiovascular death were0.1%(2cases) in aspirin combined with low-dose clopidogrel group and0.7%(12cases) in aspirin alone group. The risk ratio (HR) was0.154((95%CI:0.035～0.675),P<0.05).Myocardial infarction occurred in9patients (0.5%) in aspirin combined with low-dose clopidogrel group and27patients (1.6%) in aspirin alone group. The risk ratio (HR) was0.036((95%CI:0.153‘0.714), P<0.01).Rates of stroke were0.4%(7cases) in aspirin combined with low-dose clopidogrel group and1.6%(27cases) in aspirin alone group. The risk ratio (HR) was0.301((95%CI:0.131-0.693),P<0.01) Recurrent ischemia with rehospitalization occurred in152patients (9.0%) in aspirin combined with low-dose clopidogrel group and274patients (16.3%) in aspirin alone group. The risk ratio (HR) was0.601((95%CI:0.491-0.735), P<0.01). The cumulative survival rate in patients died of cardiac causes was significantly better in aspirin combined with low-dose clopidogrel group than in aspirin alone group (P<0.01). The cumulative incidence of major adverse cardiovascular and cerebrovascular events was significantly lower in aspirin combined with low-dose clopidogrel group than in aspirin alone group (P<0.01). There were no significant differences in total number of deaths, target vessel revascularization, stent thrombosis, incidences of severe bleeding, mild bleeding, leucopenia and thrombocytopenia between the two groups (all P>0.05). Two:Significant differences existed among group A, group B and group C in the target vessel reconstruction (P<0.05), while no significant differences existed in the other major cardiovascular and cerebrovascular events. No significant differences existed in secondary endpoint events among the three groups (P>0.05)Conclusions:One:In patients with percutaneous coronary intervention after1year, the co-administration of aspirin and low-dose clopidogrel reduces the risks of major adverse cardiovascular and cerebrovascular events:(1) significantly reduces the rate of cardiac death;(2) obviously decreases the incidence of non-fatal myocardial infarction;(3) markedly reduces the incidence of ischemic stroke;(4) evidently decreases the rate of angina incidence;(5) improved significantly in patients’(who die of cardiac causes) cumulative incidence of cumulative survival rate and major adverse cardiac and cerebrovascular events, and does not increase the risks of bleeding and cytopenia. Two:Long-term use of clopidogrel25mg/d after coronary stenting was effective and safe compared with clopidogrel50mg/d and clopidogrel75mg/d.