Impact of transfer time on mortality in acute coronary syndrome with ST-segment elevation treated by angioplasty

Summary Background In primary percutaneous coronary intervention (pPCI), conflicting data exist on the relative importance of patient presentation time (time from symptom onset (SO) to first medical contact [FMC]) and transfer time (time from FMC to sheath insertion). Objectives To evaluate the impact of transfer time on mortality in an unselected ST-elevation myocardial infarction (STEMI) population treated with pPCI. Methods In a well-organized urban network, using mobile intensive care units (MICU) whenever possible, the impact of transfer time on inhospital mortality was evaluated in 703 unselected consecutive STEMI patients transferred for pPCI. Results Our STEMI population included patients with cardiogenic shock (5.3%) and out-of-hospital cardiac arrest (3.7%). Longer transfer times were found to be associated with a stepwise increase in mortality ranging from 2.99% in the first quartile (Q1) up to 8.65% in the fourth quartile (Q4) ( P = 0.005). This result was noted in patients presenting early (≤ 2 h of SO, 0.96% for Q1 vs. 9.8% for Q4, P = 0.006) but not in late presenters (> 2 h of SO, 7.00% for Q1 vs. 7.8% for Q4, P = 0.85). After adjustment for confounding variables such as the severity of patients, the relationship between mortality and transfer time was no longer apparent. Conclusions In a well-organized urban network dedicated to pPCI, including unselected STEMI patients, transfer time does not appear to be a major contributor to mortality. The relationship of transfer time to mortality seems to be dependent on presentation time and patients’ clinical severity.