Time-dependent benefit of initial thrombosuction on myocardial reperfusion in primary percutaneous coronary intervention

Background: In ST-segment elevation acute myocardial infarction (STEMI), dislodgement of thrombus within the culprit artery during primary percutaneous coronary intervention (PCI) may cause distal embolisation and impaired myocardial reperfusion. Clinical results of thromboembolic protection strategies have been controversial. We conducted this study to investigate whether the benefit of thrombus removal is time dependent. Methods: Seventy-four STEMI patients within 12 h from onset were randomised to receive either primary PCI with initial thrombosuction (IT) or standard strategy. Results were analysed in subgroups according to the onset-to-lab time intervals (subgroup 1: 0-240 min, subgroup 2: 241-480 min and subgroup 3: 481-720 min). Results: The primary end-points were improvements in thrombolysis in myocardial infarction flow (Delta TIMI) and myocardial blush grade (Delta MBG) postprocedure. Better Delta TIMI (2.2 +/- 1.1 vs. 1.5 +/- 1.3, p = 0.014) and Delta MBG (2.3 +/- 1.1 vs. 1.0 +/- 1.5, p < 0.001) were observed in IT patients, compared with standard PCI patients. In onset-to-lab time subgroup analysis, the difference between IT and standard PCI is significant only in subgroup 2 (Delta TIMI 2.6 +/- 1.0 vs. 1.3 +/- 1.2, p = 0.007; Delta MBG 2.6 +/- 0.9 vs. 1.0 +/- 1.1, p = 0.010), but not in the other two subgroups. Conclusions: This prospective randomised study shows that primary PCI with IT may improve epicardial flow and myocardial reperfusion in patients with STEMI, and this benefit is the most significant in patients treated within 4-8 h after symptom onset.