Abstract
Objectives We evaluated the thrombus-vaporizing effect of excimer laser coronary angioplasty (ELCA) in patients with ST-segment elevation myocardial infarction (STEMI) by optical coherence tomography (OCT). Background Larger intracoronary thrombus elevates the risk of interventional treatment and mortality in patients with STEMI. Methods A total of 92 patients with STEMI who presented within 24 hours from the onset and underwent ELCA following manual aspiration thrombectomy (MT) were analyzed. Results The mean baseline thrombolysis in myocardial infarction flow grade was 0.4 ± 0.6, which subsequently improved to 2.3 ± 0.7 after MT (p < 0.0001) and 2.7 ± 0.5 after ELCA (p=0.0001). The median residual thrombus volume after MT was 65.7 mm3, which significantly reduced to 47.5 mm3 after ELCA (p < 0.0001). Plaque rupture was identified by OCT in only 22 cases (23.9%) after MT, but was distinguishable in 36 additional cases after ELCA (total: 58 cases; 63.0%). Ruptured lesions contained a higher proportion of red thrombus than nonruptured lesions (75.9% vs. 43.3%, p=0.001). Significantly larger thrombus burden after MT (69.6 mm3 vs. 56.3 mm3, p < 0.05) and greater thrombus reduction by ELCA (21.2 mm3 vs. 11.8 mm3, p < 0.01) were observed in ruptured lesions than nonruptured lesions. Conclusions ELCA effectively vaporized intracoronary thrombus in patients with STEMI even after MT. Lesions with plaque rupture contained larger thrombus burden that was frequently characterized by red thrombus and more effectively reduced by ELCA.
Highlights
Intracoronary thrombus burden is a major determinant of adverse clinical outcome in patients with ST-segment elevation myocardial infarction (STEMI)
Several randomized studies have demonstrated that manual aspiration thrombectomy (MT) for STEMI prevents the occurrence of the no reflow phenomenon and distal embolization, resulting in better myocardial reperfusion and reduced myocardial infarct size [3,4,5]
A laser size of 1.7 mm was used in >80% of cases, mainly because it is the maximum laser size compatible with a 6Fr guide catheter. e excimer laser catheter was successfully crossed distal to the culprit lesion in all cases without any balloon predilatation. e mean baseline thrombolysis in myocardial infarction (TIMI) flow grade on initial angiography was 0.4 ± 0.6. e TIMI flow grade was significantly improved by MT to 2.3 ± 0.7 (p < 0.0001) compared to that at baseline and subsequently improved by excimer laser coronary angioplasty (ELCA) to 2.7 ± 0.5 (p 0.0001) compared to that at post MT (Figure 2)
Summary
Intracoronary thrombus burden is a major determinant of adverse clinical outcome in patients with ST-segment elevation myocardial infarction (STEMI). Larger thrombus burden limits the success of percutaneous coronary intervention (PCI) for STEMI, as it increases the rate of procedural complications, such as distal embolization and no reflow phenomenon. It is associated with worse microvascular dysfunction and greater myocardial damage, thereby significantly affecting mortality [1, 2]. Erefore, theoretically, reduction of intracoronary thrombus at the culprit lesion improves the outcome of primary PCI and reduces the mortality rate in patients with STEMI. Larger randomized clinical trials have not shown the clinical benefit of the routine aspiration strategy compared with standard PCI [2, 6]. ese contradictory findings may be attributed to insufficient removal of thrombus using current aspiration thrombectomy devices
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