In the largest randomized trial so far, thrombus aspiration failed to reduce the primary endpoint of microvascular obstruction (MVO) in patients with ST-elevation myocardial infarction (STEMI) presenting late after symptom onset. Long-term clinical outcome data of this trial have not been reported yet.

A total of 144 patients with STEMI presenting ≥ 12 and ≤ 48 h after symptom onset were randomized to primary percutaneous coronary intervention (PCI) with or without manual thrombus aspiration in a 1:1 fashion. The primary efficacy endpoint was the extent of MVO assessed by cardiac magnetic resonance imaging and showed no significant difference between groups. Long-term clinical follow-up was performed at 4 years. Overall mortality at 4 years reached 18%. There was no significant difference between groups with respect to mortality and major adverse cardiac events defined as the composite of death, myocardial reinfarction and target vessel revascularization. In a multivariate Cox regression model glomerular filtration rate on admission, left ventricular ejection fraction, and cardiogenic shock were independently associated with time-dependent occurrence of death.

Routine thrombus aspiration in STEMI patients presenting late after symptom onset showed no significant difference with respect to long-term clinical endpoints compared to conventional PCI only.