The patients were randomly divided into two groups:one treated with pentoxifylline (PTX) and the other treated with low molecular dextran and acetylsalicylic acid(LMD+ASA).

• 并随机将患者分为己酮可可碱（PTX）组和低分子右旋糖酐（LMD）＋乙酰水杨酸（ASA）组对照干预治疗。