ROME – Patients undergoing cardiac surgery who ate a diet rich in antioxidants developed significantly fewer episodes of atrial fibrillation, compared with patients who consumed fewer antioxidants, in a review of 217 patients from one Italian center.
Patients in the top tertile for antioxidant consumption in their diet had roughly half the rate of new-onset atrial fibrillation following open cardiac surgery compared with the remaining patients in a multivariate adjusted analysis, Dr. Licia Iacoviello reported in a poster at the annual the annual meeting of the European Association for Cardiovascular Prevention and Rehabilitation*.
The next step will be a prospective trial with about 700 patients to test the efficacy of an antioxidant supplement to cut the development of postoperative atrial fibrillation in patients undergoing cardiac surgery, said Dr. Iacoviello, head of the laboratory of genetic and environmental epidemiology at Catholic University, Campobasso, Italy.
Mitchel L. Zoler/IMNG Medical Media
Dr. Licia Iacoviello (left) and Dr. Giovanni de Gaetano
She said that she is planning such a trial with her colleagues, but she acknowledged that an antioxidant supplement may not deliver the same materials as a diet rich in antioxidant-containing nutrients. However, intervention based on a controlled diet is difficult to standardize and run, she said in an interview.
Her report involved 217 consecutive patients who underwent coronary artery bypass grafting (CABG), cardiac valve repair or replacement surgery, or a combination of both procedures during January 2010–June 2012. The patients agreed to participate in the study and supplied full information on their diet during the year before surgery. Dr. Iacoviello and her associates analyzed the dietary questionnaire results with several tools that assess antioxidant content, including the trolox equivalent antioxidant capacity (TEAC) (J. Nutr. 2007;137:93-8). The most commonly consumed antioxidant-containing item in their diet was wine, which supplied 46% of antioxidant content, followed by coffee, which kicked in another 30%, and then fruit and fruit juices, which supplied 8% of everyone’s antioxidant consumption. The average age of the patients was 68 years; 110 (51%) underwent isolated CABG, 54 (25%) underwent isolated valve surgery, and the remaining patients had a combined procedure.
During follow-up, 84 patients (39%) developed atrial fibrillation that produced either clinically identifiable symptoms or persisted for more than 5 minutes on an ECG recording. Incident atrial fibrillation occurred in 20 (27%) of 73 patients in the highest tertile for antioxidant consumption based on their TEAC, and in 64 (44%) of the other 144 patients.
In a multivariable analysis that controlled for age, sex, diabetes treatment, a prior diagnosis of atrial fibrillation, and total energy intake, patients in the highest TEAC tertile had a statistically significant, 51% lower risk for developing atrial fibrillation, compared with patients with lower TEAC levels, Dr. Iacoviello reported.
A second analysis that focused only on the 110 patients who underwent isolated CABG showed a similar relationship. In this subgroup, the 39 patients with higher TEAC scores had a 73% reduced risk for new-onset atrial fibrillation following CABG, compared with the remaining 71 with TEAC levels in the two lowest tertiles for the overall group, a statistically significant difference.
These findings provide the first clinical evidence that high dietary levels of antioxidants may play a role in suppressing development of atrial fibrillation following cardiac surgery, said Dr. Giovanni de Gaetano, a coinvestigator on the study and director of research laboratories at Catholic University in Campobasso.
Dr. Iacoviello and Dr. de Gaetano said that they had no disclosures.
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*Correction, 5/29/2013: An earlier version of this story misstated the meeting name.