DETERMINATION OF ANGIOGRAPHIC (TIMI GRADE) BLOOD-FLOW BY INTRACORONARY DOPPLER FLOW VELOCITY DURING ACUTE MYOCARDIAL-INFARCTION

Background This study compared angiographically graded coronary blood how with intracoronary Doppler flow Velocity in patients during percut aneous transluminal coronary angioplasty (PTCA) for acute myocardial i nfarction. Different TIMI angiographic flow grades (flow grades based on results of the Thrombolysis In Myocardial Infarction trial) have be en associated with different clinical results after reperfusion for ac ute myocardial infarction. However, intracoronary blood flow velocity has not been compared with the angiographic method of determining flow grade in patients. Methods and Results Coronary flow velocity (measur ed 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. Before PTCA, 34 patients had TIMI g rade 0 or 1, 5 had TIMI grade 2, and 2 had TIMI grade 3 flow in the in farct artery. Flow velocity was similar among patients with TIMI grade s 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 less than or equal to 2 versus TIMI grade 3, respectively; P<.05). After PTCA, 1 patient had TIMI grade 1, 5 had TIMI 2, and 35 had TIMI 3 flow. Poststenotic flow velocity increased from 6.6 +/- 6.1 to 20.0 +/- 11.1 cm/s (P<.01). TI MI grade 3 flow increased to 21.8 +/- 10.9 cm/s (P<.05 versus before P TCA). Although post-PTCA flow velocity correlated with angiographic ci neframes-to-opacification count (r=.45; P<.02) for TIMI grade 3, there was a large overlap with TIMI grades less than or equal to 2 that had low flow velocity (<20 cm/s). Nine of 11 clinical events (unstable an gina and coronary artery bypass graft surgery) occurred in patients wi th low coronary flow velocity. Conclusions Determination of flow veloc ity after reperfusion may enhance patient characterization and provide the physiological rationale for clinical variations after reperfusion therapy.