Post-CABG AF affects early and late mortality

MedWire News: Postoperative atrial fibrillation (AF) affects both early and late mortality in patients who undergo isolated coronary artery bypass graft (CABG) surgery, say researchers who call for careful postoperative surveillance.

There is an ongoing debate surrounding the prognostic implications of postoperative AF, which is recognized as a difficult complication associated with significant adverse events and increased length of stay in intensive care and in hospital.

Giovanni Mariscalco, from Varese University Hospital in Italy, and colleagues studied 1832 patients who underwent isolated CABG between 2000 and 2005 at two cardiac centers, identifying patients who experienced postoperative AF and following them up until death or 2007.

The team reports in the journal Circulation that AF developed in 31% of the patients. Patients who developed AF were significantly older than those who did not, at 68.4 years versus 63.7 years.

The length of hospital stay was significantly longer for patients with AF than for those without, at 9.4 days versus 8.1 days. Patients with AF also experienced significantly higher in-hospital mortality than those without, at 3.3% versus 0.5%.

In all, 1806 patients were alive at discharge, of whom 143 were lost to follow-up. The remaining patients were followed up for a median of 51 months. After a median of 14 months, 126 patients died.

Long-term mortality was significantly higher for patients with AF than for those without, at 2.99 compared with 1.34 per 100 person-years, giving an adjusted hazard ratio (HR) of 2.13, which rose to 2.56 when also taking into account warfarin prescription at discharge.

Cox regression analysis revealed that AF patients had a significantly increased risk for cardiac causes of death, at a HR of 2.83, compared with non-AF patients. Of the cardiac causes, AF patients were significantly more likely than non-AF patients to die of embolism, at a HR of 4.33. AF patients did not face an elevated risk for non-cardiac causes of death.

The team writes: “Our results imply that appropriate antiarrhythmic and antithrombotic prophylaxis should be considered in patients after CABG.”

Circulation 2008; 118: 1612–1618