IJCS | Volume 31, Nº5, September / October 2018

516 Table 3 - Mean times delays until the performance of the primary percutaneous coronary intervention Time delays Nighttime group Daytime group p value Door-to-balloon time, minutes ± SD 101 ± 81 99 ± 78 0.59 Pain-to-balloon time, minutes ± SD 294 ± 158 278 ± 174 0.32 Statistical tests used: unpaired Student’s t-test. SD: standard deviation. Table 4 - Characteristics of the primary percutaneous coronary intervention procedures, according to the time of admission at the Hemodynamics service Characteristic Nighttime group Daytime group p value Acetylsalicylic acid, n (%) 154 (96.8) 281 (97.9) 0.19 Clopidogrel / ticagrelor, n (%) 150 (94.3) 276 (96.1) 0.32 Glycoprotein IIb/ IIIa inhibitors, n (%) 43 (27.0) 54 (18.8) 0.04 Treated vessels (territory) Anterior descending artery, n (%) 76 (47.8) 130 (45.3) 0.61 Right coronary artery, n (%) 52 (32.7) 103 (35.9) 0.49 Circumflex artery, n (%) 28 (17.6) 61 (21.3) 0.35 Left main coronary artery, n (%) 5 (3.1) 6 (2.1) 0.19 Access route Femoral, n (%) 144 (90.6) 245 (85.3) 0.11 Radial, n (%) 15 (9.4) 42 (14.6) 0.11 Pré-dilation 132 (83.0) 256 (89.2) 0.06 Post-dilation 38 (23.9) 82 (28.6) 0.28 Number of stents, total (mean stents per patient ± SD) 215 (1.3 ± 0.4) 349 (1.2 ± 0.6) 0.9 Drug-eluting stents, n (%) 7 (3.2) 19 (5.4) 0.33 Stent nominal diameter 2.98 ± 0.41 3.09 ± 0.49 0.93 Stent nominal length 23.4 ± 7.3 20.5 ± 8.1 0.91 Procedural success, n (%) 151 (94.9) 278 (96.8) 0.31 Statistical tests used: Pearson's chi-square test, Fisher's exact test, unpaired Student’s t-test and one-way Analysis of Variance. SD: standard deviation. Barbosa et al. Primary PCI at night time Int J Cardiovasc Sci. 2018;31(5)513-519 Original Article hospitalization among patients who were discharged to their homes was 6.0 ± 4.3 days in the Nighttime Group and 4.9 ± 4.0 days in the Daytime one (p = 0.91). Regarding the in-hospital evolution after the PPCI, similar mortality rates were observed in both groups. No cases of CVA were diagnosed in the total sample. In-hospital outcomes and their comparison between the Nighttime and Daytime Groups are shown in table 5. Discussion The non-business hours represent a challenge to medical assistance in the presence of STEMI, a diagnosis that requires rapid decisions and availability of several links in an urgency and emergency network. In this study, we demonstrated that it is possible to attain satisfactory results in the Brazilian scenario, with times of delay and incidence of similar adverse events among the PPCIs performed in the nighttime and daytime periods. National and international guidelines have strong recommendations for the implementation of effective STEMI treatment systems, with necessary adaptations and regionalizations. 8,11,12 This includes the integration of several links in the chain of care, especially the pre- hospital level and the availability of a referral service with Interventional Cardiology and PPCI training, aiming at increasing survival of patients with STEMI. 13-15 Nonetheless, the nighttime period usually has an on-call Interventional Cardiology team, and the increase in the time of delay can greatly affect the prognosis. Keeping the Interventional Cardiology team on duty at the referral centers is an attractive strategy to reduce the delay until the coronary reperfusion is performed and to extend the possibility of effective treatment to patients with STEMI. The applicability of PPCI within the recommended time, that is, within 90 minutes of admission to the emergency unit is, in itself, a challenge in the context of the urgency and emergency network, 16,17 and the nighttime period discloses even greater difficulties. To ensure a well-functioning and qualified