Defining an Intraoperative Hypotension Threshold in Association with Stroke in Cardiac Surgery

Abstract

What We Already Know about This Topic What This Article Tells Us That Is New Background Stroke is a leading cause of morbidity, mortality, and disability in patients undergoing cardiac surgery. Identifying modifiable perioperative stroke risk factors may lead to improved patient outcomes. The association between the severity and duration of intraoperative hypotension and postoperative stroke in patients undergoing cardiac surgery was evaluated. Methods A retrospective cohort study was conducted of adult patients who underwent cardiac surgery requiring cardiopulmonary bypass at a tertiary center between November 1, 2009, and March 31, 2015. The primary outcome was postoperative ischemic stroke. Intraoperative hypotension was defined as 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. The association between stroke and hypotension was examined by using logistic regression with propensity score adjustment. Results Among the 7,457 patients included in this analysis, 111 (1.5%) had a confirmed postoperative diagnosis of stroke. Stroke was strongly associated with 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). Other factors that were independently associated with stroke were older age, hypertension, combined coronary artery bypass graft/valve surgery, emergent operative status, prolonged cardiopulmonary bypass duration, and postoperative new-onset atrial fibrillation. Conclusions Hypotension is a potentially modifiable risk factor for perioperative stroke. The study’s findings suggest that mean arterial pressure may be an important intraoperative therapeutic hemodynamic target to reduce the incidence of stroke in patients undergoing cardiopulmonary bypass.

The relationship between neurocognitive decline and the heart‐lung machine

“…On‐pump surgeries may involve prolonged periods of hypoperfusion, further increasing patients’ risk of cerebral ischemia 1 . Such microembolic and hypoperfusive events contribute to the increased risk of stroke following procedures that use CPB 5‐12 . Of note, many studies reported that off‐pump cardiac surgeries or shorter durations of time on CPB decrease stroke risk.…”

Blood Pressure and Transient Postoperative Neurologic Deterioration, Following Superficial Temporal-to-middle Cerebral Artery Anastomosis in Adult Patients With Moyamoya Disease

“…The association between intraoperative SBP and risk of stroke has been reported in patients undergoing cardiac [14] or general surgery. [15] These previous studies emphasized the importance of preventing intraoperative hypotension for maintaining cerebral perfusion during surgery.…”

Characteristics and anatomic distribution of early vs late stroke after cardiac surgery

“…Our institutional practice is to maintain mean arterial pressures between 70 to 90 mm Hg during CPB based on a previous randomized trial showing that higher mean arterial pressures during CPB resulted in improved neurologic outcomes . A recently published Canadian trial also supports this relationship between intraoperative blood pressure and stroke …”