Background ST-segment elevation myocardial infarction (STEMI) results from occlusive thrombus formation at the site of plaque rupture or erosion.Primary percutaneous coronary intervention (PPCI) with angioplasty and stenting of the culprit lesion is the preferred approach for acute STEMI.However, despite restoration of TIMI 3 flow, dislodgement of atherothrombotic material from coronary lesions during PCI can result in distal embolization, termed the —n(e)reflow phenomenon", in 10 to 30 percent of patientsand therefore have a negative effect on long-term clinical outcome.Aspiration thrombectomy (AT) devices designed to remove the occluding thrombus and reduce the risk of distal embolization were developed.Routine use of AT/thrombectomy devices is controversial because of conflicting results of randomized trials.Objective To obtain further insight into this issue, we designed a case-control study to evaluate the usefulness of the manual thrombectomy catheter as an adjunct to primary percutaneous coronary intervention.Methods The data analyzed in this study were consecutively obtained from STEMI patients who underwent primary PCI at the Beijing Anzhen Hospital, between January 12010, and December 31 2012.The patients are followed up for 1 to 4.5 years.We applied propensity score matching to adjust for differences in baseline characteristics between patients treated with and without thrombus aspiration.The mortality 、 clinical outcome and health economic evaluation are compared between the two study groups.The cost-effective was also calculated.Results The use of adjunctive manualthrombectomy during primary percutaneous coronary intervention was safety and practicable.The percentage of direct stents was higher while the post dilatation percentage was lower post adjunctive manual thrombectomy.There were no significantly deferencein cardiac-mortality、 re-myocardial infarction、 target vessel 、 stroke and re-in-hospital and major adverse cardiac events between the two groups during 1 to 4.5 years follow-up.While it added the medical cost at the first in-hospital and did not increase the medical cost during the follow-up.Conclusion Adjunctive thrombus aspiration during PPCI couldnt reduce mortality and adverse cardiac maces, while it did not increase the medical cost during the follow-up, it added the medical cost at the first in-hospital.