Background: Percutaneous coronary intervention (PCI) is the preferred treatment for patients with ST-segment elevation myocardial infarction (STEMI). Treatment delay might result in higher rates of morbidity and mortality. As the coronarvirus disease 2019 (COVID-19) pandemic raised public concerns about virus transmission through contact with patients and health care providers, this might have affected timely treatment of STEMI patients. To analyze the suspected treatment delay of STEMI patients we used real life data from a prospective observational registry (Kölner Infarkt Modell, KIM).

Methods: The metropolitan KIM network includes STEMI patients from eleven hospitals in Cologne, Germany. PCI was performed in five hospitals with a catheterization laboratory available 24 hours a day and 7 days a week. The registry includes data on preclinical emergency treatment and in-hospital outcome. We identified peri-procedural data of patients treated during the first wave of the COVID-19 pandemic. These were compared to all other patients treated since December 2014. Patients were divided into 3 groups: A. COVID-19 pandemic group (January 27, 2020 – April 30, 2020), B. seasonal control group (January 27 – April 30 of prior years) and C. baseline control group (all other KIM patients). A subgroup analysis was performed to compare the COVID-19 pandemic group to the 2017-2018 Influenza pandemic group (December 25, 2017 – April 30, 2018). We used Student’s t-test, Fisher’s exact test and Chi square test for statistical analysis.

Results: 1,683 patients were eligible for statistical analysis. Of these, 82 (4.9%) represent the COVID-19 pandemic group, 358 (21.2%) were part of the seasonal control group, and 1,243 (73.9%) formed the baseline control group. None of the patients had a SARS-CoV-2 infection during hospitalization. Patients treated during the COVID-19 pandemic had the longest median symptom-to-contact time (A. 285.3 vs. B. 257.3 vs. C. 227 min). The difference between the COVID-19 group and the total KIM cohort was statistically significantly different (p= 0.015). The slight increase in median contact-to-balloon time in the COVID-19 pandemic group (A. 90 min) compared to the other groups did not meet statistical significance (B. 83.4 min, p=0.097; C. 84.2 min, p=0.065). The median door-to-balloon time was significantly increased in the COVID-19 group compared to the other groups (A. 53.1 vs. B. 44.7 min p=0.038; A. 53.1 vs. C. 47.7 min p=0.025). Once arrived in the catheterization laboratory, patients of all groups had an almost equal median needle-to-balloon time (A. 19.1 vs. B. 19.2 vs. C. 19.8 min). In-hospital mortality rate was 11% in groups B. and C., the corresponding rate was 6.1% in the COVID-19 pandemic group. This decrease in mortality was not statistically significant different. Subgroup analysis of the Influenza 2017/2018 pandemic group showed no statistically significant difference in symptom-to-contact time (251.6 min), door-to-balloon time (53.6 min) and needle-to-balloon time (16.9 min) in comparison with the COVID 19 pandemic group. Mortality rate was 5.9% in the Influenza pandemic group (p=1.0).

Conclusion: Overall, the COVID-19 pandemic resulted in a substantial individual and systemic treatment delay of STEMI patients. The needle-to-balloon time was similar between all groups, but pre-procedural delay resulted in increased treatment time. Even though the pandemic was challenging for health care professionals and resulted in a pre-interventional treatment delay, we observed guideline conform time intervals. Patients in the Influenza pandemic group also suffered from pre-interventional treatment delay, but we did not find statistically significant differences between both respiratory infectious diseases regarding treatment delay.