Minimizing Door-to-Balloon Time Is Not the Most Critical Factor in Improving Clinical Outcome of ST-Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention*

Objectives We tested the hypothesis that, as compared with conventional door-to-balloon, shortened door-to-balloon time would further improve 30-day outcome in ST-elevation myocardial infarction patients undergoing primary stenting. Design Retrospective cohort study Setting Academic tertiary care hospital with approximately 2600 beds Patients Between January 2008 and December 2009, 266 ST-elevation myocardial infarction patients underwent primary stenting with conventional Door-to-baloon were consecutively enrolled as group 1, while 293 ST-elevation myocardial infarction patients underwent primary stenting with shortened door-to-balloon between January 2010 and December 2011 were consecutively enrolled as group 2. Intervention Shorten door-to-balloon time. Measurements and main results The results showed that time from chest pain onset to door did not differ between two groups (p > 0.1), whereas door-to-balloon time was significantly reduced in group 2 compared with that in group 1 (p < 0.0001). The prevalences of successful reperfusion, acute and subacute stent thrombosis, 30-day death or combined endpoint (defined as congestive heart failure ≥ New York Heart Association functional class 3 or 30-d death), and left ventricular function did not differ between two groups (all p > 0.05), whereas the peak creatine phosphokinase level was significantly reduced in group 2 (< 0.05). Further analysis showed that shortening the chest pain-to-reperfusion time to less than 240 minutes was the most important factor in improving left ventricular function (p < 0.001) and 30-day combined endpoint. Multivariate analysis showed that congestive heart failure greater than or equal to New York Heart Association functional class 3, poor left ventricular function, and age (all p < 0.001) along with unsuccessful reperfusion (p = 0.25) were independently predictive of 30-day mortality. Conclusion Shortening the duration between chest pain onset and reperfusion to less than 4.0 hours was critical in reducing myocardial necrosis and improving heart function and 30-day mortality.