Sun LY, et al. - Given that to improved patient outcomes in patients undergoing cardiac surgery could be realized by identifying modifiable perioperative stroke risk factors, researchers assessed the link between the severity and duration of intraoperative hypotension and postoperative stroke in patients undergoing cardiac surgery. They found hypotension to be a potentially modifiable risk factor for perioperative stroke. According to findings, the incidence of stroke in patients undergoing cardiopulmonary bypass may be reduced by targeting intraoperative mean arterial pressure.

Methods

• This is a retrospective cohort study including adult patients who underwent cardiac surgery requiring cardiopulmonary bypass at a tertiary center between November 1, 2009, and March 31, 2015.
• Postoperative ischemic stroke was assessed as the primary outcome.
• The definition of intraoperative hypotension was the number of minutes spent within mean arterial pressure bands of less than 55, 55 to 64, and 65 to 74 mmHg before, during, and after cardiopulmonary bypass.
• They used logistic regression with propensity score adjustment in order to assess the link between stroke and hypotension.

Results

• Overall, a total of 7,457 patients were analyzed, of those, 111 (1.5%) had a confirmed postoperative diagnosis of stroke.
• Stroke was found to be strongly related to sustained mean arterial pressure of less than 64 mmHg during cardiopulmonary bypass (adjusted odds ratio 1.13; 95% CI, 1.05 to 1.21 for every 10 min of mean arterial pressure between 55 and 64 mmHg; adjusted odds ratio 1.16; 95% CI, 1.08 to 1.23 for every 10 min of mean arterial pressure less than 55 mmHg).
• Identified factors that showed independent relation to stroke included older age, hypertension, combined coronary artery bypass graft/valve surgery, emergent operative status, prolonged cardiopulmonary bypass duration, and postoperative new-onset atrial fibrillation.