Depression is fairly common after cardiac surgery, and a group of Canadian researchers identified several preoperative factors that may predict depression postoperatively, including a low left ventricular ejection fraction (LVEF), physical inactivity and being either depressed or at-risk for depression prior to surgery.

In a study published in the December 2013 issue of the Canadian Journal of Cardiology, investigators led by David Horne, MD, DCh, of the University of Manitoba in Winnipeg, Canada, quantified depression with a questionnaire in a group of 436 patients scheduled for nonemergent cardiac surgery between 2010 and 2011. They used a questionnaire and accelerometry to evaluate physical activity and surveyed patients before surgery (Q1), at the time of discharge (Q2), three months later (Q3) and six months later (Q4).

Depression increased significantly from the preoperative period to discharge, and 29 percent of patients experienced new-onset depression. Fifty-eight percent of the patients at risk for depression were depressed at discharge. The prevalence of depression during the four time periods was 23 percent, 37 percent, 21 percent and 23 percent, respectively.

Preoperative factors that independently predicted depression were LVEF of less than 50 percent, physical inactivity, being at-risk or having a history of depression, a hospital stay of more than a week, a stressful event in the postoperative period and a cardiopulmonary bypass time of more than two hours.

Patients who were more physically active were significantly less depressed at each of the time intervals based on their questionnaire scores. Patients who were not depressed before surgery and at six months after discharge reported being more physically active compared with depressed patients six months after discharge (average activity time during Q4 was 570 minutes per week vs. 420 minutes per week).

Horne et al noted that an important limitation of their study was not knowing whether depression led to physical inactivity or vice versa. However, they argued that their findings “justify more detailed perioperative assessments of depression, physical activity, and the need for assisted biopsychosocial support in patients undergoing cardiac surgery.”