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Thrombus aspiration is a well established technique in the sitting of primary coronary angioplasty for STEMI. We conducted a prospective OCT study evaluating the effect of intensive thromboaspiration in STEMI. We present here as a part of this study the characteristics of the underlying culprit lesion as seen by OCT.
Methods and Results
In a prospective non randomized single center study, 40 consecutive patients with STEMI were treated by manual thrombus aspiration guided by OCT. Once a TIMI 3 flow is obtained after a mean of 4 aspirations (standard care), a first OCT run was done to assess residual thrombus. Then aspiration was continued with an OCT run every 4 catheter passages until no further decrease in thrombus burden was observed by OCT (intensive aspiration). A mean of ten aspirations were done in order to obtain the smallest final thrombus volume which was halved as compared to thrombus burden after standard care. The OCT characteristics of the underlying lesion were studied on the last run before stenting. We evaluated the continuity of the fibrous cap and the presence of a disruption defined a plaque rupture, a thrombus attached to an intact cap characterized an OCT plaque erosion. We also studied the thickness of the fibrous cap, the presence of macrophages and the extent of the lipid pool. Plaque rupture was found as culprit lesion in 34 patients (85%) and plaque erosion in 6 patients (15%). Plaque rupture was associated with a larger thrombus burden (8.24 vs 1.62mmˆ3), a larger lipid pool (+45%), and greater macrophages accumulation (+400%). Plaque rupture was most often located upstream to the narrowest part of the lesion (85%) A larger thrombus burden was associated with the presence of plaque rupture and a longer total ischemic time. There was no correlation between thrombus volume and vessel size nor with distance between the lesion and the first collateral. In the sitting of plaque rupture and after intensive aspiration we were able to measure the volume of the removed necrotic core (8.32μ
In the setting of STEMI, 85% of culprit lesions are plaque rupture. Thrombus burden is greater in the presence of a plaque rupture when compared to a plaque erosion and is correlated to a longer total ischemic time. Shear stress seems to play a role in the location of the plaque rupture. This data emphasize the utility of an effective thrombus aspiration.