Heperin was given at the dose of 100 IU/kg immediately.With the help of X-ray fluoscopy, the tip of catheter was deployed on certain point of thoracic artery.

• 自鞘管尾端插入超声导管，在X线透视帮助下，把导管头端放置在不同肋间之下肋上缘对应的胸主动脉处，记录超声影像于录像带上。