This analysis thus fuels enthusiasm for the strategy of “facilitated PCI” for ST elevation myocardial infarction, in which pharmacological treatment is initiated while patients are being transported to the cardiac catheterization laboratory for primary PCI. Their observations add new data to the existing body of evidence supporting the benefits of rapid reperfusion. In addition, they observed that procedural success was higher in patients with baseline TIMI 3 flow. 12 Despite relatively similar baseline characteristics, those with spontaneous TIMI grade 3 flow had improved left ventricular function, lower rates of congestive heart failure, and lower mortality. After combining data from >2500 patients in the 4 Primary Angioplasty in Myocardial Infarction (PAMI) trials, they compared patients who achieved TIMI grade 3 flow spontaneously on the angiogram before primary PCI, who comprised 16% of the population, with those who had TIMI 0 to 2 flow. The outstanding analysis by Stone et al 12 sheds more light on the importance of TIMI 3 flow. 11 Thus, these various lines of evidence point to the need to shorten the time to achieving reperfusion to any extent possible, even if by just 30 minutes. 10 Finally, a similar analysis in >80 000 patients treated with thrombolytic therapy showed that increases in the door-to-drug time of just 30 minutes can lead to significant increases in mortality. In primary PCI, shorter door-to-balloon times were associated with lower mortality. 7 Thus, the benefit of t-PA on improved early left ventricular function and mortality was attributed to the earlier achievement of TIMI grade 3 flow. 9 In GUSTO I, treatment with t-PA resulted in higher rates of TIMI grade 3 flow at 60 and 90 minutes compared with streptokinase, but by 180 minutes, rates were similar. 4,8 Trials of prehospital thrombolysis, which saved between 30 and 120 minutes, demonstrated a 19% reduction in mortality. The importance of time to achieving reperfusion has also been emphasized by several types of studies, including observational studies of time to treatment versus mortality. 6,7 Thus, an active treatment that increased TIMI grade 3 flow led to improved survival. 6,7 This trial demonstrated that a more aggressive thrombolytic regimen (using tissue plasminogen activator ) that could improve the achievement of early TIMI grade 3 flow could also reduce mortality. The open artery hypothesis became the “open artery theory” 5 after the results of the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) I trial. 3,4 There is a nearly linear correlation between higher rates of early TIMI grade 3 flow and improved survival, regardless of whether reperfusion is achieved with thrombolysis or primary percutaneous coronary intervention (PCI). 2 When differentiating apparently normal TIMI grade 3 flow from more delayed TIMI grade 2 flow in patent arteries, greater myocardial salvage and improved survival were observed in patients who achieved TIMI grade 3 flow. 1 After numerous studies confirmed the benefit of a patent infarct-related artery, more careful examination of the degree of reperfusion was performed using the Thrombolysis in Myocardial Infarction (TIMI) flow grading system devised in the TIMI 1 trial. Since the advent of reperfusion therapy for acute ST elevation myocardial infarction, the “open artery hypothesis” proposed that benefit is achieved from early reperfusion of the occluded coronary artery, which limits the size of infarction, reduces the degree of left ventricular dysfunction, and improves survival. Customer Service and Ordering Information.Stroke: Vascular and Interventional Neurology.Journal of the American Heart Association (JAHA).Circ: Cardiovascular Quality & Outcomes.Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB).
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