Infarct size in primary angioplasty without on-site cardiac surgical backup versus transferal to a tertiary center: a single photon emission computed tomography study.

BACKGROUND: Primary percutaneous coronary intervention (PCI) performed in large community hospitals without cardiac surgery back-up facilities (off-site) reduces door-to-balloon time compared with emergency transferal to tertiary interventional centers (on-site). The present study was performed to explore whether off-site PCI for acute myocardial infarction results in reduced infarct size.

METHODS AND RESULTS: One hundred twenty-eight patients with acute ST-segment elevation myocardial infarction were randomly assigned to undergo primary PCI at the off-site center (n = 68) or to transferal to an on-site center (n = 60). Three days after PCI, (99m)Tc-sestamibi SPECT was performed to estimate infarct size. Off-site PCI significantly reduced door-to-balloon time compared with on-site PCI (94 +/- 54 versus 125 +/- 59 min, respectively, p < 0.01), although symptoms-to-treatment time was only insignificantly reduced (257 +/- 211 versus 286 +/- 146 min, respectively, p = 0.39). Infarct size was comparable between treatment centers (16 +/- 15 versus 14 +/- 12%, respectively p = 0.35). Multivariate analysis revealed that TIMI 0/1 flow grade at initial coronary angiography (OR 3.125, 95% CI 1.17-8.33, p = 0.023), anterior wall localization of the myocardial infarction (OR 3.44, 95% CI 1.38-8.55, p < 0.01), and development of pathological Q-waves (OR 5.07, 95% CI 2.10-12.25, p < 0.01) were independent predictors of an infarct size > 12%.

CONCLUSIONS: Off-site PCI reduces door-to-balloon time compared with transferal to a remote on-site interventional center but does not reduce infarct size. Instead, pre-PCI TIMI 0/1 flow, anterior wall infarct localization, and development of Q-waves are more important predictors of infarct size.