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Page 2 of 11 Hawkins et al. Vessel Plus 2022;6:42 https://dx.doi.org/10.20517/2574-1209.2021.116

0.0001), discharge to a facility (27% vs. 23%, P < 0.0001), and readmission (11% vs. 8%). The mean additional
total hospital cost attributable to POAF was $6705 by paired analysis. A sensitivity analysis of only patients
without major complications demonstrated similarly increased resource utilization for patients with POAF.

Conclusions: POAF was associated with an increased 9 additional ICU hours, 2 postoperative days, 18% more
discharges to a facility, and 33% greater readmissions. An additional $6705 is associated with POAF. These
conservative estimates demonstrate the broad impact of POAF on in and out of hospital resource utilization that
warrants future efforts at containment and quality improvement.

Keywords: Atrial fibrillation, cardiac surgery, resource utilization, cost

INTRODUCTION
Postoperative atrial fibrillation (POAF) is one of the most common complications after cardiac surgery. For
coronary artery bypass graft (CABG) patients the incidence is approximately 25%-30%, while after aortic
valve replacement (AVR), the incidence is 30%-40%, and combined CABG/AVR has the highest incidence
[1]
at over 35% . Onset of POAF is a time-related hazard with peak incidence on postoperative day two that
declines over the following week . The causes of POAF are multifactorial and include preoperative
[2]
structural changes and perioperative proarrhythmic adrenergic activation, inflammation, oxidative stress,
and electrolyte derangement [1,3,4] .

There is clear evidence that POAF increases morbidity and resource utilization. However, there are
considerable limitations to the estimations. The studies are retrospective, observational studies with all the
limitations that apply. Assessments of resource utilization largely utilize preoperative risk factors and risk
scores for adjustment. Finally, most do not account for other complications known to also increase resource
utilization . There is significant co-linearity of POAF and other complications that obscure a clear
[5]
delineation of the true impact of POAF. However, since prior estimates of total healthcare costs of POAF
were $1 billion back in 2008, continued efforts to update and improve resource utilization estimates are
warranted .
[6]
The Virginia Cardiac Services Quality Initiative (VCSQI) is a regional consortium of hospitals that uniquely
includes both clinical and cost data. This large cohort of patients represents an ideal opportunity to further
clarify potential associations of POAF with complications and resource utilization. We hypothesized that
POAF is associated with increased morbidity and resource utilization. Furthermore, we believe that efforts
to decrease POAF may have limited the increase in resource utilization over time as compared with overall
cost trends in cardiac surgery.

METHODS
Patient data
The VCSQI is a regional collaborative of 18 hospitals in Virginia. Hospitals submit clinical data using the
Society of Thoracic Surgeons (STS) data entry forms. Cost data is submitted using Uniform Billing-04 forms
which include final hospital charges. Clinical and cost data are merged at the patient level. Charges are
classified by the International Classification of Diseases revenue codes into cost buckets. The charges are
then multiplied by corresponding cost-to-charge ratios. Cost data were then adjusted for medical inflation
using the market basket for the Centers for Medicare and Medicaid Services Inpatient Prospective Payment
[7]
System, and presented in 2020 dollars .