| Background: Dual Anti-Platelet Therapy(DAPT) and Percutaneous Coronary Intervention(PCI) have been testified as effective clinical treatments for patients with Acute Coronary Syndromes. Current guideline for DAPT duration is 12 months, in order to reduce late and very late stent thrombosis, and for ACS patients prolonged DAPT is recommended. However, since the development of DES’s technology, DES has improved its vascular healing and re-endothelialization characteristics, and clinical tests suggest better outcomes of new generation DES. By using optical coherence tomography to investigate the vascular response after implanted second and third generation DES. At 3 months after the stent implantation, 87% of stents were covered completely with neointima, which indicate the possibility of shorten duration of DAT. All these newly found clinical evidences lead to the discussion of the optimal duration of DAPT. Many clinical trials have explored the safety and efficiency of short vs long term of DAPT usage. For ACS patients, we don’t have many clinical trials specifically target on this population, especially for DAPT’s duration after implanted DES, which need further investment.Objective: Based on current clinical trials of optimal duration of DAPT after DES, we gathered information of ACS patient’s subgroup information in order to better understanding safety and efficiency of different DAPT duration for patients with ACS.Methods: Based on instruction of Basic Methods in Medical Research and Meta Analysis Methods for Clinical Treatment by Cochrane, we designed research plan. We searched article from 2002-1 to 2015-2 from Pub Med, Cochrane Library, Clinical Trials.gov, Wan Fang and CNKI. Screening criteria include random control trail, optimal duration of DAPT after DES, and ACS subgroup’s detailed information. We also did quality evaluation for all included trails and gathered detailed information, such as number of patients, type of trials, longest follow up, etc. After heterogeneity test, we run Meta analysis compared the ischemic and bleeding event rates between short-term DAPT and long-term DAPT by Odds Ratio and 95% Confident interval.Results: We included six trails with 14,471 patients; among whom 6,199 patients have ACS and comprise 42.8% of all patient samples. 7,236 patients received short term DAPT treatment(≤6 months), and 7,235 patients received long term DAPT treatment(≥12 months). Patients with ACS compromise 42.6% and 43% in each group. In heterogeneity test, I2<50%, which indicates the homogeneity between trails and could use fixed effect model for Meta analysis. By analysis ischemic event rate and bleeding events rate between short term and long term DAPT groups, we had P=0.41 and P=0.007 representatively. These results indicate there is no statistic difference between groups for ischemic event rates, but for bleeding event, prolonging DAPT increases tendency of bleeding. Thus long term DAPT has no inferior clinical outcomes comparing to short term duration of DAPT, for both overall patients and patients with ACS.Conclusions: Based on current clinical trials, shorten duration of DAPT for patients with ACS have similar clinical efficient outcomes comparing with overall patients, while prolonging DAPT not reduces ischemic events rate, but increases bleeding risks. There is possibility for short term DAPT in clinical practice. More random clinical trials need to further support this conclusion. |
