One-year Follow-up Of Clinical Efficacy And Medication Adherence After Percutaneous Coronary Intervention

BackgroundPercutaneous coronary intervention(PCI) with intracoronary stents is now the most common procedure used in the invasive treatment of the patient with coronary artery disease(CAD).Previously randomized clinical trails have shown that drug-eluting stents(DES) significantly reduces the risk of restenosis,including the need for reintervention,compared with bare-metal stents(BMS).The cardiologists concern for possible dangers,as well as benefits,of implantation DES in CAD patients.Recent reports have indicated that there may be an increased risk of late stent thrombosis(ST) with the use of DES,as compared with BMS.Clinical trials have demonstrated the efficacy of aspirin,β-blockers(BBs), angiotensin-converting enzyme inhibitors(ACEI)/angiotensin receptor blocker (ARB),and statins medications for secondary prevention of CAD.The ACC/AHA clinical practice guidelines recommendations these medications for patients with CAD to reduce recurrent cardiovascular events.However,prior studies have shown medication nonadherence is a common problem among outpatients with CAD, limiting the effectiveness of secondary prevention medications.And little is known about the impact of nonadherence on outcomes of patients who undergone PCI procedure.ObjectivesThis study was specifically designed to assess the safety and efficacy of implantation DES in CAD patients and to determine clinical outcomes of nonadherence to evidence-based cardiovascular medications prescribed at hospital discharge at 1-year.Methods1.Study populationAll patients who underwent stenting in our hospital between October 2002 and December 2006 were included in the study.Major exclusive criteria were cardiac shock,serious diseases such as malignant tumor,serious kidney dysfunction which would influence patients' life expectation,patients treated by a combination of BMS and DES,and those lost to follow-up during 1 year.According to the type of stent implanted at the first recorded procedure,patients who received DES were assigned to the DES group;otherwise,patients were assigned to the BMS group.The patients were alive and free from MACE at hospital discharge were divided into two groups,the adheret group and the nonadheret group according to the medication adherence.The study was divided into two parts according to the cluster approach.2.Follow-upPatients were evaluated at 1 year after the stent implantation procedure and at hospital discharge,follow-up information was obtained by telephone or outpatient interview.3.Study end pointThe composite end point was the occurrence of major adverse cardiac events (MACE) and ST during 1 year;MACE were defined as a composite of cardiac death, non-fatal myocardial infarction(MI),and target vessel revascularization(TVR). Non-fatal MI including Q-wave MI and non Q-wave MI.Q-wave MI was defined as the development of new pathological Q waves in 2 or more leads lasting 0.4 seconds or more with postprocedure creatine kinase(CK)-MB levels elevated > 2.0 times normal;non-Q-wave MI was defined as the presence of CK or CK-MB levels > 2.0 times normal.New definitions of ST according to the Academic Research Consortium (ARC) was used.We selected 4 medications:aspirin,BBs,ACEI/ARB,and statins-indicated for CAD patients based on AHA/ACC Guidelines for Secondary Prevention for Patients With Coronary and Other Atherosclerotic Vascular Disease:2006 Update and examined adherence to these medications by comparing baseline prescription at hospital discharge to self-reported information during 1 year follow-up..Patients were classified as "adherent" if they were taking a regimen during 1 year follow-up which was similar to that recommended at hospital discharge.Patients were adherent if they continued all medication classes they were prescribed at discharge.Adherence was measured for each individual therapy and as an overall composite(continuation of all of the baseline therapies).4.Statistical analysesThe SPSS statistical package for Windows version 13.0 was used for the statistical analysis.Continuous variables were expressed as mean value±standard deviation(mean±SD),and the comparison between groups was made using 2 independent-samples t test;Categorical variables were by number(%),the chi-square test was used to compared categorical variables.A P value≤0.05 was considered statistically significant.Results 1.EnrollmentBetween October 2002 and December 2006,565 patients at our hospital were underwent stenting,in which 20 patients treated by a combination of BMS and DES, 3 patients with cardiac shock,1 patient with serious kidney dysfunction,51 patients were lost to follow-up during 1 year,and 3 patients died or suffer from MI in hospitalization.2.Baseline characteristics and follow-up outcomes--Part one of studyThe population included in the analysis consisted of 490 patients:231 were BMS group,and 259 were DES group.Baseline clinical characteristics were comparable,except that DES group patients had more hypertension(P=0.010),less acute MI(P=0.007) compared with BMS group patients(Table 1-2).Lesion and procedural characteristics revealed several differences between the 2 groups(Table 1-3).2-or 3-vessel diseases of DES group was significant higher than that of BMS group(P=0.001,P=0.001,respectively);The DES group was more frequently associated with a PCI of the LM(P=0.000),type B2/C lesions(P= 0.001);and implantation of 2 or more stents(P=0.036,P=0.000,respectively). Stent length per lesion of DES group was significant longer than that of BMS group (P=0.014);Stent diameter per lesion was similar between the 2 groups(P=0.675).During 1 year follow-up,the accumulated incidence of MACE and TVR in BMS group was significantly higher than that of DES group(P=0.030,P=0.043, respectively).The two study groups did not differ significantly in the composite of all-cause death(P=0.891),cardiac death(P=1.000),non-fatal MI(P=0.581) (Table 1-4,Figure 1-1).According to the ST definition of ARC,accumulative incidence of ST was 1.7% for BMS group compared with 1.9%for DES group(P=1.000).The incidence of acute ST(P=1.000),sub-acute ST(P=1.000),late ST(P=1.000) were similar between the 2 groups(Table 1-5,Figure 1-2).The incidence of definite ST(P= 1.000),probable ST(P = 1.000),possible ST(P = 1.000) were similar between the 2 groups(Table 1-6,Figure 1-3).3.Baseline characteristics and follow-up outcomes--Part two of studyThe population included in the analysis consisted of 487 patients:241 were adheret group,and 246 were nonadheret group.Baseline clinical characteristics were comparable,except that nonadherent group patients had more old MI(P = 0.023) compared with adherent group patients(Table 2-1).At discharge,aspirin was prescribed in 100.0%,BBs in 55.6%,ACEI/ARB in 58.7%,and statins in 89.1%among patients.The proportion of patients who adherent to aspirin,BBs,ACEI/ARB,and statins was 85.0%,81.9%,79.7%,and 61.8%, respectively.Adherence was lowest for statins and highest for aspirin(Table 2-2, Figure 2-1).At discharge,the proportion of patients who use of 1-,2-,3-,and 4-type of drugs was 3.7%,22.8%,40.9%,and 32.6%,respectively.During 1-year follow-up,the proportion of patients who use of 1-,2-,3-,and 4-type of drugs was 16.8%,28.3%, 35.3%,and 14.6%,respectively,and 5.0%patients in our study discontinued use of all drugs(Table 2-3,Figure 2-2).During 1-year follow-up,the accumulated incidence of MACE and TVR in nonadheret group was significantly higher than that of adheret group(P = 0.006,P = 0.025,respectively).The two study groups did not differ significantly in the composite of cardiac death(P = 0.080),non-fatal MI(P = 1.000)(Table 2-5,Figure 2-3).ConclusionImplantation of DES results in a similar rate of cardiac death and non-fatal MI,a lower rate of MACE,and a less frequent need for TVR,as compared with BMS:the use of DES in routine daily practice does not appear to be associated with a higher rate of ST than BMS 1 year after the procedure.Patients undergone PCI frequently stop medications within 1-year of prescription;nonadherence to cardioprotective medications results in a similar rate of non-fatal MI and cardiac death,a higher rate of MACE,and a more frequent need for TVR,as compared with adherence to cardioprotective medications.