Intraluminal Thrombus in Facilitated Versus Primary Percutaneous Coronary Intervention: An Angiographic Substudy of the ASSENT-4 PCI (Assessment of the Safety and Efficacy of a New Treatment Strategy With Percutaneous Coronary Intervention) Trial
What is the effect of facilitated percutaneous coronary intervention (PCI) on presence and consequence of intraluminal thrombus?
The authors reported data from the angiographic substudy of the ASSENT-4 trial. Angiographic findings, including residual Thrombolysis In Myocardial Infarction (TIMI) thrombus grade 2 and/or distal embolization and/or slow flow deemed to reflect thrombus burden following PCI, were correlated with ST-segment resolution, epicardial blood flow, and clinical outcome. The clinical composite endpoint was death, congestive heart failure, or shock.
Patients in the facilitated PCI group were more likely to have TIMI flow grade 2/3 in the infarct-related artery at the first angiogram (73.7% vs. 33.4%, p < 0.001) compared with patients undergoing primary PCI. However, they also had a higher thrombus burden following PCI (19.7% vs. 13.4%, p = 0.002) compared with patients in the primary PCI group. There was no difference in the post-PCI TIMI flow between the two groups. Post-PCI TIMI thrombus grade was significantly associated with ST-segment resolution (p < 0.001) and TIMI frame count (p < 0.0001) in both groups. Facilitation with tenecteplase (p = 0.005) and thrombus burden (odds ratio, 2.43; 95% confidence interval, 1.30-4.51; p = 0.0052) were independent predictors of 90-day mortality in addition to age, Killip class, and anterior wall infarction.
The use of facilitated PCI was associated with better initial patency of the infarct-related artery, but higher residual thrombus burden and worse clinical outcomes.
The study provides some mechanistic insights underlying the worse outcomes associated with facilitated PCI. The results of the ASSENT-4 and FINESSE trials (N Engl J Med 2008;358:2205-17) clearly demonstrate that clinical outcomes with facilitated PCI are worse than those with primary PCI, and thus, facilitated PCI has all but been abandoned in clinical practice.
Keywords: Myocardial Infarction, Thrombosis, Heart Failure, Percutaneous Coronary Intervention
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