Background:Coronavirus Disease-2019 (COVID-19) may impair outcomes of patients with ST-segment elevation myocardial infarction (STEMI). The extent of this phenomenon and its mechanisms are unclear.

Methods and Results:This study prospectively included 50 consecutive STEMI patients admitted to our center for primary percutaneous coronary intervention (PCI) at the peak of the Italian COVID-19 outbreak. At admission, a COVID-19 test was positive in 24 patients (48%), negative in 26 (52%). The primary endpoint was in-hospital all-cause mortality. Upon admission, COVID-19 subjects had lower PO2/FiO2 (169 [100–425] vs. 390 [302–477], P<0.01), more need for oxygen support (62.5% vs. 26.9%, P=0.02) and a higher rate of myocardial dysfunction (ejection fraction <30% in 45.8% vs. 19.2%, P=0.04). All patients underwent emergency angiography. In 12.5% of COVID-19 patients, no culprit lesions were detected, thus PCI was performed in 87.5% and 100% of COVID-19 positive and negative patients, respectively (P=0.10). Despite a higher rate of obstinate thrombosis in the COVID-19 group (47.6% vs. 11.5%, P<0.01), the PCI result was similar (TIMI 2-3 in 90.5% vs. 100%, P=0.19). In-hospital mortality was 41.7% and 3.8% in COVID-19 positive and negative patients, respectively (P<0.01). Respiratory failure was the leading cause of death (80%) in the COVID-19 group, frequently associated with severe myocardial dysfunction.

Conclusions:In-hospital mortality of COVID-19 patients with STEMI remains high despite successful PCI, mainly due to coexisting severe respiratory failure. This may be a critical factor in patient management and treatment selection.