The rates of direct stenting are higher among patients randomized to thrombus aspiration. The rates of clinical events and myocardial reperfusion did not differ significantly between a direct stenting strategy vs. predilation and stenting, and no interaction was observed as regards thrombus aspiration.
Several preliminary studies have emerged from the hypothesis that a direct stenting strategy during primary angioplasty could reduce microvascular obstruction and clinical event rates. Thrombus aspiration might facilitate a direct stenting strategy by allowing us to better assess the distal bed through flow recovery after nitroglycerin administration. Furthermore, we might be able to choose a stent length and diameter that better fit the lesion. By recovering some of the flow, we might be able to perform direct stenting with the help of an angiography instead of occluding the lesion with the stent, thus risking, particularly, the distal end.
This work analyzed the 3 largest randomized studies testing routine manual thrombus aspiration compared with conventional angioplasty. Propensity score matching was used to compare the populations who underwent direct stenting vs. conventional angioplasty, and other statistical resources were used to assess their interaction with thrombus aspiration.
Among the overall population (n = 17,329), 32% underwent direct stenting and 68% underwent conventional angioplasty.
Direct stenting was more frequent among patients who underwent thrombus aspiration (41% vs. 22%; p < 0.001) and this was associated with lower contrast doses (162 mL vs. 172 mL; p < 0.001) and shorter fluoroscopy time (11.1 min vs. 13.3 min; p < 0.001).
After propensity score matching (n = 10,944), no significant differences were observed between these strategies regarding 30-day death (1.7% vs. 1.9%; p = 0.6), or 30-day stroke (0.6% vs. 0.4%; p = 0.99). One-year results were similar and there were no differences as regards electrocardiography or myocardial reperfusion.
Primary angioplasty is very dynamic and no routine strategy showed any benefit. Sometimes, merely crossing the guidewire helps us recover part of the flow, allowing us to assess the distal bed, the lesion length, and the right artery diameter with some degree of precision. (There is always some degree of spasm, and nitroglycerin administration seems necessary if the hemodynamic status of the patient allows it). In these cases, direct stenting at low-atmosphere pressures (we can always use post-dilation) seems to be the fastest, simplest, and lowest-risk strategy as regards embolism of the microcirculation. If the distal bed is not observable, thrombus aspiration can help. Upon the persistence of TIMI flow 0, predilation with a small-diameter balloon at low-atmosphere pressures may allow us to somewhat see the distal bed in order to decide on the next step to be taken.
No study has shown improvement of hard endpoints during primary angioplasty as a result of systematic use of a given strategy. In consequence, we must be prepared for all courses of action and experience will teach us which strategy is more convenient in each case. Undoubtedly, 10-mL contrast and 2-min fluoroscopy time are not endpoints that may modify our daily clinical practice.
Original title: Clinical Impact of Direct Stenting and Interaction with Thrombus Aspiration in Patients with ST-Segment Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention: Thrombectomy Trialists Collaboration.
Reference: Karim D. Mahmoud et al. European Heart Journal (2018) 39, 2472-2479.
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