The benefits of manual thrombus aspiration (TA) during primary percutaneous coronary intervention (pPCI) for ST-elevation myocardial infarction (STEMI) remain uncertain. We assessed the influence of total ischemic time (TIT) on clinical outcomes among STEMI patients undergoing manual TA during pPCI.

We conducted a retrospective study of patients enrolled in the Acute Myocardial Infarction in Switzerland Plus registry. STEMI patients undergoing pPCI with (TA group) or without (PCI-alone group) manual TA were stratified based on short (<3 hours), intermediate (3-6 hours), and long (>6 hours) TIT. The primary endpoint was in-hospital all-cause mortality. The secondary endpoint was in-hospital major adverse cardiac events (MACE), a composite of all-cause death, myocardial reinfarction and stroke.

Between 2008 and 2014, 4’154 patients (TA 48%) were included. Risk-adjusted in-hospital all-cause mortality was not different between TA and PCI-alone groups (OR 1.29; 95%CI 0.83-1.98; p=0.26), whereas there was significantly increased risk of MACE (OR 1.52; 95%CI 1.05-2.19; p=0.03) in patients treated with manual TA compared with PCI-alone. There was no significant difference between manual TA and PCI-alone with respect to risk-adjusted all-cause mortality according to TIT groups, but risk-adjusted MACE rates were significantly higher in the group of patients with long TIT treated with manual TA compared with PCI-alone (OR 2.42; 95%CI 1.16-5.04; p=0.02).

In a large registry of STEMI patients, manual TA was not associated with lower risk-adjusted in-hospital all-cause mortality compared with PCI-alone regardless of TIT but was associated with significantly greater risk of MACE. In patients with prolonged TIT, manual TA was associated with higher risk-adjusted MACE rates compared with PCI-alone.