Closed versus open cell stent for high-risk percutaneous coronary interventions in ST-elevation acute myocardial infarction: the Closed versus Open Cells stent for High risk percutaneous coronary Interventions in ST-Elevation acute myocardial infarction (COCHISE) pilot study.

Background: Stent deployment may be associated with distal embolization and slow flow in coronary thrombotic lesions. There are no data on the risk of distal thrombus embolization according to the stent design. The aim was to evaluate coronary flow after percutaneous coronary interventions (PCI) in acute myocardial infarction according to the employed stent (closed versus open cell design).

Methods: From March 2010 to December 2011, 223 consecutive patients with acute ST-elevation myocardial infarction were randomized to primary PCI either with an open cell (112 patients, 88 men) or with a closed cell stent design (111 patients, 92 men). The primary endpoint was the corrected TIMI frame count (cTFC) after the procedure.

Results: There were no significant differences in procedural success nor in-stent deployment in the 2 groups. At baseline, there were no significant differences in cTFC between the 2 groups (70 ± 37 and 67 ± 39, P = .65, respectively). After the procedure, the open cell group showed significantly higher cTFC compared to the closed cell group (18 ± 11 and 15 ± 5, P = .003 respectively). This difference was associated with a significant lower rate of TIMI 3 flow (87% and 95%, P = .037) and myocardial blush grade 3 (65% and 87%, P = .001) in the open compared to the closed cell group. There were 2 cases of death in the open cell and 1 case in the closed cell group.

Conclusions: The use of a closed cell stent design rather than an open cell during PCI for acute ST-elevation myocardial infarction is associated with better coronary angiographic flow after PCI.