Routine thrombus aspiration before percutaneous coronary intervention (PCI) showed no significant benefit for reperfusion success in patients with ST-segment elevation myocardial infarction (STEMI) who present late after onset, according to results published JACC: Cardiovascular Interventions.
Although thrombus aspiration is an established treatment for STEMI patients undergoing PCI, previous studies have reported a minimal reduction in mortality and possibly an increase in stroke. Since most research has focused on patients presenting within the first hours after symptom onset, investigators sought to assess the reduction in microvascular obstruction (MVO) in STEMI patients presenting late after symptom onset.
The extent of MVO as assed by cardiac magnetic resonance (CMR) in the modified intention-to-treat population served as the primary efficacy end point. Researchers randomly assigned 152 patients with subacute STEMI presenting between ≥12 and ≤48 hours after symptom onset to undergo PCI with or without manual thrombus aspiration. All patients underwent cardiac magnetic resonance imaging (CMR) 1 to 4 days after randomization.
“Aspiration thrombectomy did not reduce the extent of MVO compared with standard PCI without thrombectomy, which was corroborated by a lack of benefit in secondary end points,” the authors reported. “Patients with STEMI with symptom onset-to reperfusion times >12 hours had only a moderate amount of salvageable myocardium.”
The mean time between symptom onset and PCI for the total cohort was 28 ± 12 hours, and approximately 60% of the patients showed at least a moderate amount of viable myocardium in the affected region.
After PCI, MVO was present in 59% (n=33) of patients after thrombectomy and 64% (n=35) of patients who underwent conventional PCI (P=.69). The extent of MVO was not significantly different between the patients in the thrombus aspiration and control groups (2.5% ± 4.0% vs 3.1% ± 4.4% of left ventricular mass, P=.47).
The CMR results showed that left ventricular ejection fraction was moderately impaired (45% ± 11%) and the myocardial salvage index was 27 ± 26. The myocardial salvage index, infarct size, and MVO showed no significant difference among patients in the shortest, intermediate, and longest tertiles of time from symptom onset to PCI.
The authors note that future studies should explore other treatment modalities to further reduce microvascular injury in patients with STEMI.
Desch S, Stiermaier T, de Waha S, et al. Thrombus Aspiration in Patients with ST-Segment Elevation Myocardial Infarction Presenting Late After Symptom Onset. JACC Cardiovasc Interv. 2016; 9(2): 113-22. doi: 10.1016/j.jcin.2015.09.010.