![]() ![]() After reperfusion, reestablishment and maintenance of normal antegrade coronary blood flow is dependent on a combination of interactive factors, including postreperfusion vessel lumen dimension at the site of a recanalized occlusion and the extent of ischemic damage to both the epicardial conduit endothelium and myocardial microvasculature. 4 6 7 8 9Īcute coronary artery occlusion and subsequent reperfusion produce profound changes in coronary physiology and myocardial function. Patients with TIMI flow grade 3 show improved regional and global left ventricular function, lower enzyme peaks, and reduced morbidity and mortality rates compared with patients with TIMI flow grades 0, 1, or 2. 10 However, more recent studies 7 have identified a disparity with regard to clinical outcomes after thrombolysis when patients are stratified between TIMI flow grades ≤2 and TIMI grade 3. 3 4 5 6 7 8 9 In early analyses, both TIMI flow grades 2 and 3 were considered indicative of successful reperfusion. 1 2 Determination of TIMI flow grade after coronary reperfusion yields important prognostic information in patients with acute myocardial infarction. The TIMI flow grade has become the standard for semiquantitative evaluation of myocardial perfusion before and after coronary reperfusion therapies. The Thrombolysis In Myocardial Infarction (TIMI) study group developed a grading scale for coronary blood flow based on visual assessment of the rate of contrast opacification of the infarct artery. Nine of 11 clinical events (unstable angina and coronary artery bypass graft surgery) occurred in patients with low coronary flow velocity.Ĭonclusions Determination of flow velocity after reperfusion may enhance patient characterization and provide the physiological rationale for clinical variations after reperfusion therapy. Although post-PTCA flow velocity correlated with angiographic cineframes-to-opacification count ( r=.45 P<.02) for TIMI grade 3, there was a large overlap with TIMI grades ≤2 that had low flow velocity (<20 cm/s). TIMI grade 3 flow increased to 21.8☑0.9 cm/s ( P<.05 versus before PTCA). Poststenotic flow velocity increased from 6.6☖.1 to 20.0☑1.1 cm/s ( P<.01). After PTCA, 1 patient had TIMI grade 1, 5 had TIMI 2, and 35 had TIMI 3 flow. Flow velocity was similar among patients with TIMI grades 0, 1, or 2 but was lower than in those with TIMI grade 3 flow (9.4±5.4 versus 16.0±5.4 cm/s for TIMI grades ≤2 versus TIMI grade 3, respectively P<.05). Before PTCA, 34 patients had TIMI grade 0 or 1, 5 had TIMI grade 2, and 2 had TIMI grade 3 flow in the infarct artery. Methods and Results Coronary flow velocity (measured by use of a Doppler guidewire) during primary or rescue PTCA in 41 acute myocardial infarction patients was compared with TIMI grade and cineframes-to-opacification count. However, intracoronary blood flow velocity has not been compared with the angiographic method of determining flow grade in patients. Different TIMI angiographic flow grades (flow grades based on results of the Thrombolysis In Myocardial Infarction trial) have been associated with different clinical results after reperfusion for acute myocardial infarction. Customer Service and Ordering Informationīackground This study compared angiographically graded coronary blood flow with intracoronary Doppler flow velocity in patients during percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction.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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