Introduction: The importance of time-to-primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction has been controversial. We examine the relationship between time-to-treatment and short- to medium-term clinical outcomes.
Methods: In a prospective observational study of data collected from our institution's angioplasty database between June 2001 and May 2003, 208 consecutive patients (mean age 56.0 [range, 28-90] years; 88.5 percent men; 23.6 percent with diabetes mellitus) with ST-segment elevation myocardial infarction (STEMI) and who underwent primary PCI without antecedent fibrinolytic therapy were analysed. With adjustments for appropriate covariates, logistic regressions were performed to assess the relationship between symptom-to-balloon time, door-to-balloon time and the studied outcomes, which were mortality and major adverse cardiac event (MACE) defined as death, myocardial infarction and repeat target vessel revascularisation.
Results: Prolonged symptom-to-balloon time (median time, 3 hours 55 minutes) significantly increased the MACE rate at one month (odds-ratio [OR], 1.45; 95 percent confidence interval [CI], 1.09-1.92; p-value is 0.011) and six months (OR, 1.19; 95 percent CI, 1.01-1.41; p-value is 0.046) but not mortality (at one month, p-value is 0.25; at six months, p-value is 0.87) after adjusting for relevant covariates. However, door-to-balloon time (median time, 110 minutes) did not significantly influence mortality (mortality at one month, p-value is 0.73; six months, p-value is 0.64) and MACE (MACE at one month, p-value is 0.71; six months, p-value is 0.08) at one and six months.
Conclusion: Symptom-to-balloon time is an important predictor of MACE in the short- and medium-term in contrast to door-to-balloon time. Improving public awareness and accessibility of health services to patients with STEMI is essential in reducing poor outcomes.