Post-CABG Risk of AF Is Low in African Americans

DENVER — Several recent studies have shown that the prevalence of atrial fibrillation in the general population is considerably lower in African Americans than in whites. New evidence indicates this is also the case in the setting of post–coronary artery bypass graft.

“It's counterintuitive because of the fact that African Americans have a lot more of the risk factors that lead to atrial fibrillation, like high blood pressure, heart failure, and diabetes. There's something fundamentally different that alters the risk for atrial fibrillation in African Americans,” Dr. Marc K. Lahiri observed at the meeting.

He presented a retrospective study involving 270 African Americans and 731 whites with no prior atrial fibrillation (AF) who underwent CABG at Henry Ford Hospital in Detroit. Postoperative AF occurred in 29% of the white patients compared with 19% of African Americans.

In a multivariate analysis adjusted for age, gender, heart failure, hypertension, and diabetes, black race remained a highly significant independent predictor of reduced risk of postop AF, with a 47% lower risk than in whites, according to Dr. Lahiri, senior staff physician at Henry Ford.

“Since it appears that Caucasians are at an increased risk of developing postoperative atrial fibrillation, clinicians may want to use this information in deciding when to take measures to prevent its occurrence,” Dr. Lahiri added.

Some have argued that the reported lower prevalence of AF among African Americans in the general population could be an artifact of underdiagnosis due to reduced access to health care. That explanation, however, would not explain the lower incidence of post-CABG AF in African Americans, since that arrhythmia occurs when patients are still hospitalized and closely monitored following their cardiac surgery.

Also at the meeting, Dr. Gerald V. Naccarelli presented a retrospective cross-sectional study involving nearly 6.3 million adult Medicaid enrollees in eight states, of whom 1.3% carried a diagnosis of nontransient AF.

After the researchers controlled for established AF risk factors in a multivariate logistic regression analysis, the odds of having AF were 40% lower in African Americans and 17% lower in Hispanics than in whites, according to Dr. Naccarelli, professor of medicine and chief of the division of cardiology at Milton S. Hershey Medical Center in Hershey, Pa.

Disclosures: Dr. Naccarelli's study was supported by Sanofi-Aventis. He disclosed receiving significant research support from and serving as a consultant to the company. Dr. Lahiri reported no conflicts.

'There's something fundamentally different that alters the risk … in African Americans.'

Source DR. LAHIRI