The difficult task of reducing symptom-onset-to-balloon time among patients undergoing primary PCI

Background. Organizing integrated systems of care for patients with ST-segment-elevation myocardial infarction (STEMI) addresses only a part of the overall delay to reperfusion, thus omitting the symptom duration before the first medical contact. Purpose. We study the effect of a pre-hospital ECG tele-transmission program on the symptom-onset-to-balloon time in patients with STEMI referred by Emergency Medical Service (EMS) for primary percutaneous coronary intervention (PCI). Methods. We analysed 335 STEMI patients who were transported by EMS to our Institution for primary PCI between January 2007 and June 2014. Reperfusion times were calculated in 1) patients without ECG tele-transmission first evaluated at the Emergency Department (non tele), 2) patients with ECG tele-transmission but initially admitted to the Coronary Care Unit (tele-CCU), 3) patients with ECG tele-transmission directly routed from the field to the catheterization laboratory (tele-cath lab). Results. Median first medical contact-to-balloon time and door-to-balloon time were remarkable lower in the tele-cath lab group (85 min [IQR 70-102] and 42 min [IQR 34-50], respectively) in comparison to the other groups (p<0.0001). In parallel, the proportion of patients with FMCTB time ≤ 90 min increased from 11% (non tele), to 39% (tele-CCU) and to 57.2% (tele-cath lab) (p for trends <0.0001) and the proportion of patients with DTB time ≤ 90 min increased from 51% (non tele group), to 70.4 % (tele-CCU) and to 98 % (tele-cath lab group) (p for trends <0.0001).Symptom-onset-to-balloon time declined significantly (p<0.0001) from 200 min, IQR 164-239.5 (non tele) to 160.5 min, 122.5-204.7 (tele-cath lab) and the proportion of patients who received primary PCI < 120 minutes increased (p<0.0001) from 4.3 % (non tele) to 24% (tele-cath lab). Conclusions. Prehospital diagnosis of STEMI followed by the direct transfer of the patient to the catheterization laboratory rooms reduces the system delay in the execution of reperfusion treatment. Morever, although the implementation of telemedicine in processes of STEMI care may improve the symptom-onset-to-balloon time, a large proportion of patients still continued to be treated beyond the goal of 120 minutes. To reduce the total ischemic time, it is not sufficient to have an efficient integrated STEMI-network but it is necessary to identify new strategies that target the decision delay patient time