The Effect Of Thrombus Aspiration Therapy In Primary Percutaneous Coronary Intervention For Acute ST-segment Elevation Myocardial Infarction

Background:The key of the treatment for Acute ST-segment Elevation Myocardial Infarction(STEMI) is how to open the occluded coronary artery as soon as possible for the recovery of the blood supply in the myocardial level,avoiding further myocardial necrosis and ventricular remodeling and lowering the related mortality and severe complications.Primary percutaneous coronary intervention(PCI) has deeply changed the landscape of the treatment of STEMI with a significantly lower incidence of STEMI related mortality and better clinical outcomes.Because of the above facts,PCI has been widely used in the treatment of STEMI.However,primary PCI still has some drawbacks in the treatment of the thrombotic lesions with a relatively higher incidence of no-reflow or low-reflow,causing incomplete perfusion in the myocardial level.Compared to patients who have complete blood perfusion in myocardial level,patients with no-reflow or low-reflow have significantly higher incidences of subsequent chronic heart failure,malignant arrhythmia,cardiac death and adverse left ventricular remodeling.In the context,how to recover the blood perfusion in the myocardial level is the key of the revascularization of STEMI. Several studies,to date,have showed that the use of thrombus aspiration devices can significantly lower the incidences of post-procedural no-reflow and slow-reflow,and significantly improve their subsequent clinical outcomes in patients with STEMI.In the present,we randomly used Zeek thrombus aspiration catheter in the treatment of thrombotic lesions in patients with STEMI to evaluate safety and effectiveness of thrombus aspiration in this subset setting.Methods:a total of 59 patients with STEMI who were hospitalized in the cardiac department of Tianjin NanKai hospital were consecutively enrolled from March 2008 to January 2008,and were randomly divided into the following 2 groups:Zeek+PCI group(thrombotic aspiration group,n=29) and PCI group(control group,n=30). Patients in thrombotic aspiration group received thrombotic aspiration before PCI. Clinical,angiographic and PCI procedural characteristics and clinical outcomes at 6 months were compared between these two groups:1.Thrombotic aspiration therapy:After a 0.014 inch guidewire was advanced into the distal part of coronary artery through the culprit lesion,Zeek thrombotic aspiration catheter was inserted to the culprit lesion via the wire and 30mL injector was connected to the catheter.As we carefully drawback or advance the catheter through culprit lesion,aspiration under negative pressure was continuously performed with the injector.The thrombus in the culprit lesion was drawn out of body via the aspiration catheter.According to the angiographic results,repeated aspirations were performed until the optimal antegrade blood flow were finally restored.According to the remaining stenosis,direct stenting or stenting after balloon pre-dilation were performed.2.Standard PCI were performed as follows.After the guidewire advanced the distal part of coronary artery via the culprit lesion,one or multiple stents were deployed after balloon pre-dilation.3.TIMI blood flow:TIMI grade 0:no blood flow reach the distal part of the culprit lesion;TIMI gradeⅠ:only part of contrast dye reach the distal part of the culprit lesion but it could not fully cover the distal coronary artery;TIMI gradeⅡ:the contrast dye can fully cover the distal coronary artery,but the speed of flow and clearance were slower than normal level.TIMI grade 3:the contrast dye can fully cover the distal coronary artery and its flow and clearance was as quick as the normal level.4.Corrected TIMI frame count:the number of frames was counted when the contrast dye was seen from the coronary ostium to the standard angiographic distal part of coronary artery.5.TIMI myocardial perfusion grade:grade 0:no myocardial visualization;grade 1: small amount of myocardial visualization;grade 2:moderate amount of myocardial visualization,but the density is lower than the myocardium which is perfused by ipsilateral or contralateral normal coronary artery.Myocardium received partial perfusion;grade 3:normal myocardial visualization and its density is same as the myocardium which is perfused by ipsilateral or contralateral normal coronary artery.Myocardium received complete reperfusion.6.Elevated ST segment resolution rate determination:ECGs were collected 1 hour before PCI and post PCI.The speed of ECG paper is 25mm/s.TP segment was chosen as equipotential line,and the height of ST segment at 0.08 s after QRS terminal was measured.The change rate of ST segment was calculated as following equation:ST change rate=(pre-PCI∑ST-post-PCI∑ST)/pre-PCI∑ST.7.Plasmatic CK and CK-MB determination:using biochemical automatic analyzer, the plasmatic CK,CK-MB levels were determined at 8,12,14,16,18,20 hours after symptom onset,and peak values were analyzed.The performance rate method was used to determine CK and CK-MB levels.8.Echocardiographic parameters:left ventricular ejection fraction(LVEF) and end-diastolic left ventricular diameter(LVEDD) were determined at 1 week after PCI.9.Clinical follow-up:All of the patients were clinically followed up to 6 months. Patients received follow-up via call every week,and they visited outpatient department every month.The major adverse cardiovascular events and medical treatments were recorded throughout the all follow-up period.Results:1.Post-procedural TIMIⅢblood flow rate:The aspiration group had a significantly higher rate of post-procedural TIMIⅢblood flow as compared with control group (P=0.039).2.The number of post-procedural corrected TIMI frames:The aspiration group had a significantly lower corrected TIMI frame number as compared with control group (P=0.001).3.Post-procedural TIMI myocardial perfusion:Patients in aspiration group had a higher rate of TMP grade 3 blood flow after PCI(P=0.007) while a lower rate of TMP grade 0-1 blood flow(P=0.030) as compared with those in control group.4.Elevated ST segment resolution rate:More patients in aspiration group had sumSTR＞70%(P=0.019) at 1 hour after PCI,while fewer patient in aspiration group had sumSTR＜30%(P=0.030) as compared with those in control group,it suggested that treatment with aspiration catheter could improve significantly the myocardial perfusion in patients with STEMI.5.Patients in the aspiration group had significantly lower peak values of CK and CK-MB as compared with those in control group(P＜0.001),it suggested that treatment with aspiration catheter could decrease the myocardial infarct size in patients with STEMI.6.Patients in the aspiration group had significantly higher EF(P=0.001) and lower end-diastolic diameter(P=0.004) as compared with those in control group,it showed that the application of aspiration catheter during primary PCI procedure in patients with STEMI could increase the left ventricular ejection fraction,decrease the left ventricular enddiastolic dimension,improve left ventricular function.7.Clinical outcomes up to 6 months after PCI:There was 1 death in aspiration group and 1 recurrent myocardial infarction in control group during the in-hospital stay (P＞0.05),while there was no MACE in either group during the 6-month follow-up (P＞0.05).8.The results of the use of aspiration catheter:Among 29 patients who used aspiration catheter,23 patients(79.3%) had visible micro plaque and thrombus in their aspiration contents,and 8 patients(27.6%) had large thrombus.A total of 18 patients(62.1%) in the aspiration group received direct stent without balloon pre-dilation.Conclusions:1.The use of aspiration catheter in patients with STEMI significantly improved the myocardial perfusion after PCI and reduced the incidence of no-reflow.2.The use of aspiration catheter in patients with STEMI significantly reduced the size of myocardial necrosis and improved the patients' cardiac function.3.The use of aspiration catheter can facilitate the PCI procedure,reduce the consuming of predilation balloon,and decrease the procedure-associated cost.4.The treatment with ZEEK aspiration catheter to STEMI patients is safe and effective,and can be used widely.