Background: COVID-19 has changed the world as we know it, and the United States continues to accumulate the largest number of COVID-related deaths worldwide. There exists a paucity of data regarding the effect of COVID-19 on adult cardiac surgery trends and outcomes on regional and national levels.

Methods: The STS Adult Cardiac Surgery Database was queried from January 1, 2018 to June 30, 2020. The Johns Hopkins COVID-19 database was queried from February 1, 2020 to January 1, 2021. Surgical and COVID-19 volumes, trends, and outcomes were analyzed on a national and regional level. Observed-to-expected ratios were used to analyze risk-adjustable mortality.

Results: 717,103 adult cardiac surgery patients and over 20 million COVID-19 patients were analyzed. Nationally, there was 52.7% reduction in adult cardiac surgery volume, and 65.5% reduction in elective cases. The Mid-Atlantic region was most affected by the first COVID-19 surge, with 69.7% reduction in overall case volume and 80.0% reduction in elective cases. In the Mid-Atlantic and New England regions, the observed-to-expected mortality for isolated coronary bypass increased as much as 1.48 times (148% increase) pre-COVID rates. After the first COVID-19 surge, nationwide cardiac surgical case volumes did not return to baseline, indicating a COVID-19-associated deficit of cardiac surgery patients.

Conclusions: This is the largest analysis of COVID-19 related impact on adult cardiac surgery volume, trends, and outcomes. During the pandemic, cardiac surgery volume suffered dramatically, particularly in the Mid-Atlantic and New England regions during the first COVID-19 surge, with a concurrent increase in observed-to-expected 30-day mortality.