ABC | Volume 112, Nº4, April 2019

Original Article Balk et al Transfer time in STEMI patients Arq Bras Cardiol. 2019; 112(4):402-407 Figure 3 – Correlation between distance from the place of origin and mean delta T (minutes). 200 200 250 300 150 150 100 100 50 50 0 Distance (km) from the place of origin Median delta T (minutes) R = 0.55 p < 0.001 In a time period lower than 2 hours, primary PTCA was superior to fibrinolytic therapy in terms of severe adverse effects (death, stroke and reinfarction; 13 event rates were 8.5% vs 14.2%, respectively; p = 0.02). The benefit of transferring STEMI patients for PTCA on in‑hospital mortality, compared with onsite fibrinolytic therapy, decreased as transfer time increased. In-hospital mortality was 2.7%, 3.6% and 5.7% in PTCA group and 7.4%, 5.5% and 6.1% in fibrinolytic therapy group for delays of 0-60 minutes, 60-90 minutes and longer than 90 minutes, respectively. 14 In our study, mean transfer time was 141 minutes, with wide variation according to patients’ place of origin. In the cities of Porto Alegre, Viamão and São Leopoldo, transfer time was shorter than 120 minutes. In all other cities, however, it was longer than recommended, reducing the benefits of the immediate transport of patients for primary angioplasty. Figure 1 more clearly illustrates the relationship between travel distance and prolonged transfer time. White areas in the map correspond to cities where no transfer of STEMI patients for primary angioplasty was registered. Therefore, patients from these areas were not included for analysis, although it is likely that their transfer times were similar to those in the cities nearby, and higher than predicted. An arm of the GRACE study with 3,959 patients compared fibrinolytic therapy with primary angioplasty, and showed a door-to-needle time of 35 minutes and door-to-balloon time of 78 minutes. Treatment delays were associated with an increase in 6-month mortality for both therapies. For each 10-min delay in door-to-needle, mortality increased by 0.30% for patients who underwent thrombolysis, and 0.18% for those who underwent primary PCI. 15 In patients with chest pain treatedwithin 3 hours of symptom onset, no difference in mortality was observed between PTCA and fibrinolysis (7.2% vs . 7.4%). Nevertheless, in those treated between 3–12 h after symptom onset, mortality significantly increased in fibrinolysis group compared with PTCA (6.0% vs. 15.3%). 16 In centers without catheterization facilities, i.e., when patient transfer is required, thrombolysis should be performed, since, if carried out within 3 hours of STEMI, both angioplasty and thrombolytic therapy have similar benefit on mortality. Besides, between 3 hours and 12 hours of pain onset, in places where transfer time is expected to be longer than ideal transfer time, thrombolysis should be strongly considered. For calculation of the total ischemic time, one should consider the delay in seeking medical care, the time until AMI diagnosis, delays in patients’ transfer to the catheterization laboratory, and internal delays of the referral system, from patients’ enrollment to the opening of the infarct-related artery. In a previous study performed in our institution, the mean time from symptom onset to hospital admission was 90 minutes during business hours and 133 minutes outside this period. 17 Limitations of the study Despite the quantitative nature of delta T, this variable can be difficult to be evaluated, resulting in measurement errors. In addition, since this study consisted in a database review, there are potential biases, inherent to this type of analysis. 405