Genomics and Postoperative Atrial Fibrillation

Postoperative Atrial Fibrillation has been shown to increase the length of hospital stay; markedly increase cost and potentially increases the incidence of post-operative stroke. Nationally, postoperative atrial fibrillation (AF) is a common complication of cardiac surgery, occurring in 25% to 40% of patients and total costs of billions of dollars per year to treat At University of Pittsburgh Presbyterian University Hospital, over the past few years, our patients experience AF in the postoperative period at an average rate of 30% -40%. The incidence of postoperative AF increases with the age of the patient. The average age of the patient that undergoes CABG surgery has been on the increase due to the improved longevity of the population.

Coronary artery bypass grafting is associated with systemic inflammatory response. There have been studies performed to assess the relationship of genetic polymorphisms that could affect the expression of cytokines such as interleukin 6 (IL-6). Interleukin 6 is a pro-inflammatory cytokine and major mediator of acute phase response. The correlation between the -174 G/C polymorphism and the high production of IL-6 has enabled some investigators to anticipate and treat the patients prophylactically to reduce the IL-6 levels. 8

It has been suggested that inflammation can have a role in the development of atrial arrhythmias after cardiac surgery and that genetic predisposition to develop postoperative complications exists. There have been studies performed in Europe to ascertain this association and it has been found that the -174G/C Interleukin-6 promoter gene variant appears to modulate the inflammatory response to surgery and to influence the development of postoperative AF. These data suggest an inflammatory component of postoperative atrial arrhythmias and a genetic predisposition to this complication , this polymorphism has also been correlated with the development of postoperative renal and pulmonary complications.

Enrolled patients will have a single blood sample of 6 ml drawn prior to their CABG surgery.

Any personal identifiers on the blood sample tube will be removed and code numbers specific for this research study will be affixed on to the samples by the research coordinator before the samples are sent to the Genomics laboratory for analyses.