The effects of the COVID-19 pandemic have resulted in a substantial decline in overall heart surgery volume and an unexplained increase in deaths after coronary artery bypass grafting in the US, says a new study.

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"The pandemic has changed the world as we know it, causing a dramatic drop in adult cardiac surgery volume and worsening patient outcomes," said Tom Nguyen from the University of California, San Francisco. For the study, the researchers queried the STS Adult Cardiac Surgery Database, a clinical outcomes registry for adult cardiac surgery, from January 1, 2018, to June 30, 2020, and The Johns Hopkins COVID-19 Dashboard from February 1, 2020, to January 1, 2021.

The researchers examined data from 717,103 adult cardiac surgery patients and more than 20 million COVID-19 patients in an effort to determine how the pandemic affected adult cardiac surgery on national and regional levels. The results showed that there was a 53 percent decrease nationwide in all adult cardiac surgery volume when compared to 2019 and 65 percent fewer elective cases in the US. The COVID-19 also impacted non-elective cases, resulting in a 40 percent decrease, according to the findings presented at the 57th Annual Meeting of The Society of Thoracic Surgeons being held from January 29-31.

Though the data did not directly address the cause of increased mortality, many surgeons said they currently are limited to operating on only the most urgent coronary bypass cases and patients who tend to be sicker. "These numbers should not serve as a deterrent to patients seeking care for chest pain or other cardiac symptoms," said Robbin Cohen from Keck School of Medicine of the University of Southern California in Los Angeles, who was not directly involved with this study. "If anything, they are a warning to get into the system as soon as possible."

The total number of global coronavirus cases has topped 102.5 million, while the deaths have surged to more than 2.21 million, according to the Johns Hopkins University. The US is the worst-hit country with the world's highest number of cases and deaths at 26,067,807 and 439,420, respectively, according to the data.