According to published research, new onset post-operative atrial fibrillation (POAF) is one of the most common complications following cardiac surgery, with incidence rates ranging between 10% and 30% in this patient population. The risk of atrial fibrillation increases with age, and the elderly population is a group that is increasingly undergoing cardiac operations. “Studies have shown that POAF is an important determinant of postoperative length of stay, resource utilization, and readmission rates, but the magnitude of this impact has not been well characterized,” says Gorav Ailawadi, MD. He says a better understanding is needed regarding the impact of POAF on patient outcomes, hospital resources, and healthcare costs. Finding ways to reduce POAF incidence may improve outcomes and decrease associated costs.

A Closer Look

The Virginia Cardiac Surgery Quality Initiative (VCSQI) is a voluntary consortium of 17 cardiac surgery centers in Virginia that exchanges and compares data in an effort to improve patient outcomes, quality, and costs. The VCSQI—which links to the national Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database—aims to identify quality improvement opportunities and find ways to enhance surgical processes of care. Dr. Ailawadi and colleagues had a study published in Annals of Thoracic Surgery that used these data to examine the impact of POAF on mortality, hospital resources, and costs among multiple centers.

For the study, investigators examined more than 49,000 patient records from the STS-certified database for cardiac operations from 2001 to 2012 and stratified patients by the presence of POAF versus non-POAF. New onset POAF occurred in one-out-of-five cardiac surgery patients and was associated with an increased risk of additional complications. “After risk adjustment, our study showed that POAF was associated with double the risk of patient mortality, additional hours in the ICU and days in the hospital, and higher ICU- and total hospital-related costs,” says Dr. Ailawadi (Table 1). The findings of increased morbidity and mortality associated with POAF are consistent with previous investigations of cardiac surgical populations.

To account for potential confounding in the data, the researchers estimated the risk-adjusted associations between POAF and other important factors using hierarchic multiple regression models for various procedure types. After adjusting for the influence of baseline patient risk, operative features, surgeon and hospital variability, and operative era, POAF was associated with about a twofold higher risk of mortality for isolated CABG and aortic valve procedures. POAF also correlated with an approximate twofold greater likelihood of major morbidity for all procedure types (Table 2). In addition, POAF was associated with a twofold to fourfold increased risk of stroke after CABG and replacement operations, greater hospital resource utilization, and higher costs.

Notably, the authors observed a 2.6% incidence of stroke among POAF patients. They also reported an increased risk-adjusted association between POAF and stroke for most procedure types, a finding that is consistent with rates reported in other studies. The rate of stroke associated with POAF is pertinent to clinicians because studies indicate that preventing strokes has the potential to greatly reduce long-term morbidity after cardiac surgery.

Protocols Needed

Patient care is under increasing scrutiny, and there is a need to develop protocols that are designed to reduce the incidence of POAF. Such protocols have the potential to impact patient outcomes and improve the ability to deliver high-quality, cost-effective patient care. “The VCSQI has discussed and partially implemented efforts to reduce atrial fibrillation in certain centers,” says Dr. Ailawadi. He notes that an exact protocol has yet to be fully implemented within all participating centers, but the VCSQI is currently looking to further the adoption of collaborative protocols and a set of best practice guidelines to reduce POAF rates.

Looking Ahead

The study by Dr. Ailawadi and colleagues provides a robust platform that can be used to analyze forthcoming efforts aimed at avoiding and treating POAF after cardiac surgery. “Our findings provide an up-to-date benchmark for current and future analyses relating to the impact of POAF after cardiac surgery,” he says. “More data are still needed to determine the true costs associated with efforts aimed at reducing the incidence of POAF and to clarify the most cost-effective strategies for cardiac surgical patients. Currently, there are few reports that provide modern estimates of the higher costs associated with POAF. Future analyses should also explore the impact of added costs from using pharmacologic efforts to prevent and treat POAF after cardiac surgery.”

References

LaPar DJ, Speir AM, Crosby IK; Investigators for the Virginia Cardiac Surgery Quality Initiative; et al. Postoperative atrial fibrillation significantly increases mortality, hospital readmission, and hospital costs. Ann Thorac Surg. 2014;98:527-533. Available at: http://www.annalsthoracicsurgery.org/article/S0003-4975(14)00700-0/fulltext.

Filardo G1, Hamilton C, Hebeler Jr RF, Hamman B, Grayburn P. New-onset postoperative atrial fibrillation after isolated coronary artery bypass graft surgery and long-term survival. Circ Cardiovasc Qual Outcomes. 2009;2:164-169.

Rostagno C, La Meir M, Gelsomino S, et al. Atrial fibrillation after cardiac surgery: incidence, risk factors, and economic burden. J Cardiothorac Vasc Anesth. 2010;24:952-958.

Kalavrouziotis D, Buth KJ, Ali IS. The impact of new-onset atrial fibrillation on in-hospital mortality following cardiac surgery. Chest. 2007;131:833-839.

Mathew JP, Fontes ML, Tudor IC, et al. A multicenter risk index for atrial fibrillation after cardiac surgery. JAMA. 2004;291:1720-1729.

Bramer S, van Straten AH, Soliman Hamad MA, Berreklouw E, Martens EJ, Maessen JG. The impact of new-onset postoperative atrial fibrillation on mortality after coronary artery bypass grafting. Ann Thorac Surg. 2010;90:443-449.