Comparison of coronary arterial finding by intravascular ultrasound in patients with "transient no-reflow" versus "reflow" during percutaneous coronary intervention in acute coronary syndrome.

Previous studies have shown that transient no-reflow during coronary intervention but with Thrombosis in Myocardial Infarction (TIMI) grade 3 flow at the completion of the procedure is associated with increased in-hospital and 6-month mortality. We hypothesized that the use of intravascular ultrasound before intervention could identify morphologic features that were predictive of transient no-reflow in patients who had acute coronary syndrome (ACS). We analyzed 220 patients with ACS who had suitable intravascular ultrasound images that were acquired before intervention. We defined "transient no-reflow" as TIMI grade 0, 1, or 2 flow during the procedure and TIMI grade 3 flow at the completion of the procedure. We defined "reflow" as good coronary flow (TIMI grade 3 flow) during and after the procedure. Patients were categorized to a transient no-reflow group (n = 20) or a reflow group (n = 200). In the transient no-reflow group, vessel area and amount of plaque burden in the culprit lesion were significantly greater than in the reflow group (vessel 20.8 +/- 5.4 vs 16.4 +/- 6.2 mm(2), p < 0.01; plaque burden 0.90 +/- 0.03 vs 0.83 +/- 0.08, p < 0.001). The presence of ruptured plaque, lipid pool-like images, and thrombus formation were significantly higher in the transient no-reflow group than in the reflow group. Multivariate analysis identified the presence of thrombus formation (odds ratio 4.53, 95% confidence interval 1.03 to 20.0, p = 0.04) and larger plaque burden (odds ratio 1.79, 95% confidence interval 1.01 to 3.23, p = 0.05) as independent predictors of transient no-reflow. In conclusion, lesion morphologies are different for transient no-reflow and reflow. These findings suggest that the presence of thrombus formation and large plaque burden increase the risk for developing transient no-reflow during coronary intervention for ACS.