Abstract
Background: Coronavirus disease 2019 (COVID-19) has impacted on cardiovascular disease. However, it remains unclear whether the COVID-19 pandemic has impacted on disease severity and patients' prognosis of acute myocardial infarction (AMI) in Japan. Methods and Results: We retrospectively accumulated data from the Japanese Registry of All Cardiac and Vascular Diseases-Diagnosis Procedure Combination (JROAD-DPC) study (April 2019 to March 2021). Patients were divided into a before COVID-19 pandemic group or a during COVID-19 pandemic group. The proportion of patients who presented with cardiogenic shock (Killip class IV) was compared between groups, in association with 30-day mortality as the primary outcome. Killip class IV AMI significantly increased in the during COVID-19 pandemic group (15.7% vs. 14.5% in the before pandemic group, P<0.0001). The 30-day mortality was higher in the during COVID-19 pandemic group (9.6% vs. 9.2% in the before COVID-19 pandemic group, P=0.049). However, there was no significant difference in the adjusted 30-day mortality in each Killip class between the before and during COVID-19 pandemic groups. Conclusions: During the early stage of the COVID-19 pandemic in Japan, 30-day mortality of AMI increased, mainly because of the increase of Killip class IV AMI patients. However, irrespective of the COVID-19 pandemic, the adjusted 30-day mortality of each Killip classification group was unchanged.