News:Extended Use of Clopidogrel is Associated with Reduction in Death or Death and Non-fatal Myocardial Infarction among Diabetics following PCI

June 3, 2008 By Vijayalakshmi Kunadian MBBS MD MRCP [mailto:vkunadian@perfuse.org]

Drug eluting stents (DES) are preferred for diabetic patients undergoing percutaneous coronary intervention (PCI). Premature discontinuation of clopidogrel therapy following DES PCI is a predictor of stent thrombosis (ST). In a recent publication in JACC, Brar and colleagues determined the long term outcomes (death, non fatal myocardial infarction) following the use of DES compared with bare metal stents (BMS) after adjusting for clopidogrel use among diabetic patient population in an observational study.

The study population consisted of diabetic patients who underwent PCI using either DES or BMS between October 2002 and December 2004 at a single center in Los Angeles. Patients were divided into those how received BMS and DES. Patients who died or suffered non-fatal MI or underwent revascularization within the first 6 months were excluded from the study. The groups were further subdivided into clopidogrel users (those that were on clopidogrel therapy >180 days from the index PCI date) and clopidogrel non users (those that discontinued clopidogrel by 180 days). The final analysis consisted of 4 groups: DES with clopidogrel, DES without clopidogrel, BMS with clopidogrel and BMS without clopidogrel. The study cohort was further divided into 3 groups depending on the duration of clopidogrel use: < 6 months, 6-9 months and >9 months. The primary endpoint of this study consisted of a composite of all-cause death and non fatal myocardial infarction.

The final analysis of this study consisted of 671 patients, in whom 919 stents were implanted. The mean age was 62.7±10.8 years. A Kaplan-Meier analysis demonstrated that the cumulative incidence of death and non fatal MI was similar between the DES and BMS groups during the first 180 days. After 180 days, the composite of death and myocardial infarction was greater in the BMS group (p=0.05) with no difference in death (p=0.33).

The analysis by stent type and clopidogrel use demonstrated that the cumulative incidence of death and non fatal MI was greater in the BMS without clopidogrel group (12.2%) compared to BMS with clopidogrel group (3.5%, p=0.01) and a trend towards an increase in cumulative events in the DES without clopidogrel group (5.5%) compared to DES with clopidogrel group (2.2%, p=0.07). Furthermore, an analysis by stent type and clopidogrel use demonstrated that the incidence of death alone was greater in the DES without clopidogrel group (3.9%) compared to DES with clopidogrel group (1%, p=0.03), with no difference in death between the entire DES (1.8%) and BMS (3.6%) groups (p=0.18). Among clopidogrel non users, the cumulative events and death alone were similar between DES and BMS groups (p=0.11, p=0.40 respectively).

The cumulative death and non fatal myocardial infarction by clopidogrel duration was significantly greater among those who were on clopidogrel for < 6 months (16.5%), compared with those who were on it for 6-9 months (9.4%) and > 9 months (3.2%, p<0.001). Likewise the incidence of death alone was greater among those who were on clopidogrel for < 6 months (10%), compared with those who were on it for 6-9 months (4.3%) and > 9 months (0.5%, p<0.001).

The investigators of this study conclude that prolonged use of clopidogrel following PCI using DES and BMS among diabetic patients resulted in a significant reduction in death and non fatal myocardial infarction. Although this study is an observational one, it confirms previous observations and reiterates the need for prolonged clopidogrel therapy following PCI with both DES and BMS in order to reduce cardiovascular outcomes. These findings however, will need to be confirmed in large scale randomized clinical trials.

Source

 * 1) http://content.onlinejacc.org/cgi/content/abstract/51/23/2220.