Time from first medical contact to reperfusion in ST elevation myocardial infarction: A Which Early ST Elevation Myocardial Infarction Therapy (WEST) substudy

BACKGROUND: Recent research and contemporary ST elevation rnyocardial infarction guidelines emphasize the importance of prompt reperfusion and have redefined the traditional time to treatment metric to include prehospital paramedical staff as the point of first medical contact. However, an important knowledge gap exists relating to data systematically addressing the impact of arrival at the hospital by ambulance and the delays inherent in transfer front it community hospital to tertiary centres for percutaneous coronary intervention (PCI). METHODS: The Which Early ST Elevation Myocardial Infarction Therapy (WEST) study initiated treatment at the point of first medical contact, including prehospital contact. Patients Were randomly assigned to receive fibrinolysis Will) usual care or coupled with mechanical cointervention, or primary PCI. To assess the impact of this strategy on time to treatment, the following randomly assigned patient groups Were compared: prehospital versus in-hospital; those arriving at the hospital by ambulance versus ambulatory self transport; and those whose initial hospital care was a community versus PCI centre. RESULTS: Of the 328 patients enrolled in the Study, 221 received fibrinolysis and 107 received primary PCI. Compared with the in-hospital group, patients who underwent prehospital random assignment (44%, n=145) experienced it 48 min reduction in median (interquartile range) time from symptom onset to first Study medication (87 min [65 min to 147 min] versus 135 min [95 min to 186 min]; P<0.001) and it 56 min reduction ill time to first balloon inflation (148 min [117 min to 214 min] versus 204 min [166 min to 290 min]; P<0.001). Arrival by ambulance without prehospital random assignment (n=90) incurred it substantial delay from first medical contact to reperfusion (fibrinolysis 76 min [63 min to 105 min] and PCI 160 min [141 min to 212 min]) compared with prehospital random assignment (n=145; fibrinolysis 43 min 133 min to 54 min] and PCI 105 min [90 min to 127 min)) or ambulatory patients (n=93; fibrinolysis 47 min [32 min to 68 min] and PCI 108 min [85 min to 150 min]). Community (n=165) versus PCI hospital (n=163) random assignment was associated with a longer delay from first medical contact to reperfusion: fibrinolysis, 56 min versus 47 min (P=0.008) and primary PCI, 139 min versus 105 min (P=0.001). DISCUSSION: Prehospital diagnosis, random assignment and treatment substantially reduced treatment delay with both pharmacological and mechanical reperfusion. Those activating the prehospital medical response system without receiving prehospital random assignment experienced the longest delay from first medical contact to reperfusion, indicating it lost opportunity to enhance ST elevation myocardial infarction patient outcomes.