P5474STEMI time presentation, are circadian patterns and week hours related to the outcome?
Authors: Rodriguez Arias J J , Ortega-Paz L O , Masotti M M , Freixa X F , Regueiro A R , Sabate M S , Brugaletta S B 
Published: October 2019

Background

Previous studies have suggested that patients treated during night hours had significantly longer delay times than those treated during day hours without difference in terms of in-hospital mortality. A circadian pattern can also be seen in STEMI presentation but data analyzing a relationship between this circadian pattern and prognosis are missing.

Objective

We aimed to evaluate clinical outcomes of STEMI patients according to the time of medical attention (on-hour vs off-hour) and to the circadian pattern.

Methods

Observational, multicenter study, based on prospectively collected data from consecutive patients treated within the STEMI Network during the period between January 2010 and December 2015. On-hour presentation included patients treated between 8:00h and 19:59h on weekdays, the rest were catalogued as off-hour presentation. In the circadian pattern analysis, event frequencies were analyzed by time of onset in keeping with a circular distribution over the 24-hour clock. The Rayleigh test was used to evaluate the hypothesis of a uniform distribution of times. The primary endpoint was 1-year all-cause mortality. Secondary endpoints were 30-day all-cause mortality and in-hospital complications.

Results

A total of 8608 patients were included, 3795 (44.1%) in on-hour group and 4813 (55.9%) in off-hour group. There were significant differences with a shorter patient delay (157±227min vs. 141±193min; p<0.01) and longer system delay (132±86 min vs. 152±111min; p<0.01) in the on-hour vs. off-hour group. However, there was no difference in total ischemic time (287±256 min vs. 293±242 min; p=0.265). At 30-day and 1-year follow-up there were no differences in adjusted all-cause mortality between groups [OR 0.91 (CI95%: 0.73–1.12; p=0.35) and OR 0.99 (CI95%: 0.83–1.17; p=0.87), respectively]. In-hospital atrioventricular block was more frequent in on-hour group as compared to off-hour (4.2% vs 3.3%; p=0.02).

A circadian pattern was observed between 9:00 am and 12:30 pm, patients presenting a circadian pattern showed a shorter patient delay (135.29±186.83min vs. 152.44±215.11min; p<0.01), system delay (134.93±89.36min vs. 145.63±104.93min; p<0.01) and total ischemic time (270.78±255.55min vs. 270.34±227.34min; p<0.01) with no differences in 30-day and 1-year mortality between patients with or without the pattern [OR 1.02 (IC95%: 0.81–1.30; p=0.85) and OR 1.12 (IC95%: 0.92 - 1.36; p=0.25) respectively]. This circadian pattern was repeated each day weekly during the period of the study.

Conclusions

Off-hour STEMI presentation was associated with a shorter patient delay and longer system delay without an increase in total ischemic time. The off-hour presentation was not related to an increase in 1-year all-cause mortality when compared to on-hour. A circadian pattern was found, patients included in this group presented a shorter total ischemic time without differences in 30-day and 1-year mortality.