The largest analysis of its kind to look at the impact of COVID-19 on adult cardiac surgery volume, trends and outcomes in the USA has found that during the first surge of the pandemic in early 2020 cardiac volume suffered dramatically, with a concurrent increase in observed-to-expected 30-day mortality.
The analysis was published in The Annals of Thoracic Surgery, and used data from more than 700,000 cardiac surgery patients from the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD) captured between 1 January 2018 and 30 June 2020, and over 20 million COVID-19 patients from the Johns Hopkins COVID-19 database, taken from 1 February 2020 to 1 January 2021.
In the paper, author Tom Nguyen (University of California San Francisco, San Francisco, USA) and colleagues examined trends relating to cardiac surgery and COVID-19 from both a regional and a national perspective, using observed-to-expected ratios to analyse risk-adjustable mortality.
They report that nationally, a 52.7% reduction in adult cardiac surgery volume was seen, with a 65.5% reduction in elective cases. The Mid-Atlantic region was reported to be the most acutely impacted during the initial COVID-19 surge, with a 69.7% reduction in overall case volume, and an 80% reduction in elective cases.
In the Mid-Atlantic and New England regions, Nguyen and colleagues report, the observed-to-expected mortality for isolated coronary bypass increased as much as 1.48 times (148% increase) compared to pre-COVID-19 rates.
“After examination of nearly three-quarters of a million adult cardiac surgical cases and more than 20 million COVID-19 cases, a clear nadir of cardiac surgical volumes was seen in April 2020, with reductions to less than half of the previous level, notably including a nearly 40% reduction in all non-elective cases,” Nguyen and colleagues report. “When focused temporally on the first nationwide COVID-19 surge in the spring of 2020, cardiac case volumes in the Mid-Atlantic and New England regions were affected to the greatest degree, with an even greater reduction in non-elective cases by nearly 60% in the Mid-Atlantic.”
Furthermore, they note that when examining cardiac surgical volumes after April 2020, though some volume recovery was seen, there was not a rebound of case volumes to above-baseline levels that would account for the previous non-elective cardiac surgical case deficit, either regionally nor nationally. This finding suggests a COVID-19 related deficit of untreated adult cardiac surgery patients, Nguyen and colleagues write.
Speculating on the possible explanations for the absence of a “rebound” in cases, the authors write that some patients may have opted for less-invasive alternatives to surgery, such as percutaneous coronary intervention (PCI) instead of coronary artery bypass grafting (CABG) or transcatheter aortic valve implantation (TAVI) instead of aortic valve replacement. However, this suggestion is also refuted, as the authors note that data from other hotspot regions suggest a concomitant reduction in overall and relative PCI rates during the early COVID-19 surge.
Another potential explanation put forward is that patients may be reluctant to seek appropriate in-hospital care at all in the midst of a pandemic because they fear contracting COVID-19, or further overwhelming their local healthcare system. “Although this mechanism is difficult to quantify nationally, it is supported by the growing number of late-presenting complications of myocardial infarction and other acute cardiac diseases which timely, invasive therapies may have mitigated,” they write.
Speaking to Cardiovascular News Nguyen stressed the importance of avoiding further disruption to surgery volumes—particularly for non-elective cases—during the latest wave of the virus.