How long is too long? Association of time delay to successful reperfusion and ventricular function outcome in acute myocardial infarction: the case for thrombolytic therapy before planned angioplasty for acute myocardial infarction.
OBJECTIVE
The purpose of this study was to quantify the effect of time delays to reperfusion on ventricular function after myocardial infarction. This allows one to identify a group of patients in whom a strategy using antecedent pharmacologic reperfusion therapy before planned direct angioplasty may offer significant benefit.


BACKGROUND
Direct angioplasty for myocardial infarction is associated with a high rate of successful reperfusion compared with pharmacologic reperfusion. However, there is an inherent time delay to treatment with angioplasty compared with pharmacologic therapy. There currently are insufficient data to determine the consequences of incremental time delays to reperfusion on ventricular function.


METHODS
We determined, by logistic regression analysis, the probability of observing a decrement in postmyocardial infarction ventricular function as a function of incremental time delays to reperfusion.


RESULTS
Time delays of 30, 60, 90, or 120 minutes to reperfusion increased the likelihood of a worse ventricular function outcome by 1.1-, 1.3-, 1.5-, and 1.7-fold, respectively (P <.02). The upper 95% confidence limits around these odds ratios are as high as 1.3 or 2.7 for 30- and 120-minute delays, respectively. Time from symptom onset to patency remained a significant determinant of ventricular function after adjustment for clinical and procedural factors.


CONCLUSIONS
Delay in time to reperfusion, measured in minutes, results in significant loss of ventricular function after myocardial infarction. Interventional strategies designed for treatment of myocardial infarction when "door-to-balloon" time is expected to exceed 60 minutes should strongly consider incorporation of pharmacologic reperfusion therapy into the therapeutic paradigm.
Lundergan
Conor F
CF
Cardiovascular Research Institute and the PACT Core Angiographic Laboratory, The George Washington University, Washington, DC 20037, USA. domcfl@gwumc.edu
Reiner
Jonathan S
JS
Ross
Allan M
AM
D000208:Acute Disease; D000800:Angioplasty, Balloon / Q000379:methods; D003131:Combined Modality Therapy; D003289:Convalescence; D017023:Coronary Angiography; D004311:Double-Blind Method; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000601:surgery*; D009204:Myocardial Revascularization / Q000379:methods*; D017063:Outcome Assessment, Health Care; D010919:Placebos; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology*
D005343:Fibrinolytic Agents; D010919:Placebos; D010959:Tissue Plasminogen Activator