When are cerebral infarctions most likely to occur after open heart surgery, also known as coronary artery bypass grafting (CABG)?

From the Guidelines

Cerebral infarctions after open heart surgery are most likely to occur within the first 24 hours postoperatively, with a significant portion of strokes occurring after an uneventful recovery from anesthesia. This timing is supported by the fact that only around 40% of strokes following CABG are identified within the first day after surgery, while 60% of strokes occur after the initial recovery period 1. The risk of cerebral infarction is further increased by factors such as age, smaller body surface area, emergency surgery, previous stroke, pre-operative atrial fibrillation, and on-pump CABG with hypothermic circulatory arrest 1.

Risk Factors and Timing

The convergence of several risk factors unique to the perioperative period contributes to the high risk of cerebral infarction during this time. These include:

• Microemboli formation from aortic manipulation, cardiopulmonary bypass circuits, or cardiac chambers
• Hemodynamic instability, including hypotension or low cardiac output states, which can compromise cerebral perfusion
• The inflammatory response triggered by cardiopulmonary bypass, potentially contributing to microvascular dysfunction and thrombosis
• Pre-existing risk factors such as carotid stenosis, previous stroke, advanced age, diabetes, or atrial fibrillation

Monitoring and Intervention

Vigilant neurological monitoring is essential during the first 72 hours post-surgery, with prompt investigation of any new neurological symptoms to enable early intervention. Continuous monitoring of the electrocardiogram for arrhythmias should be performed for at least 48 hours in all patients after CABG 1. Additionally, the use of specialized monitoring techniques, such as cerebral oximetry with near-infrared spectroscopy, may be helpful in predicting early perioperative cognitive decline, stroke, and noncerebral complications 1.

Clinical Implications

The highest quality evidence suggests that the risk of stroke after CABG is significant, with a 30-day rate of stroke of 1.8% after CABG compared to 0.3% after PCI 1. Therefore, it is crucial to prioritize vigilant monitoring and early intervention to minimize the risk of cerebral infarction and improve outcomes in patients undergoing open heart surgery.

From the Research

Cerebral Infarctions after Open Heart Surgery

Cerebral infarctions, also known as strokes, can occur after open heart surgery, including coronary artery bypass grafting (CABG). The timing of these events can vary, but research suggests that they are most likely to occur during or within 30 days after surgery 2.

Risk Factors for Cerebral Infarctions

Several factors can increase the risk of cerebral infarctions after open heart surgery, including:

• A history of ischemic stroke or transitory ischemic attack 2
• Large vessel cerebral vascular disease, although this may not be as significant a factor as small vessel disease 3
• Small vessel cerebral vascular disease, which has been associated with impaired cerebral autoregulation during cardiopulmonary bypass 3
• Intraoperative blood loss ≥800 mL 4
• The presence of a "shaggy aorta" 4
• Left subclavian artery coverage, carotid artery debranching, and pull-through wire use during surgery 4

Timing of Cerebral Infarctions

While the exact timing of cerebral infarctions after open heart surgery can vary, research suggests that they can occur:

• During surgery 5
• Within 30 days after surgery 2
• At any point during the perioperative period, which is defined as the period of time extending from the decision to operate to the recovery from the anesthesia and surgery 2

Preventive Strategies

Several strategies may help prevent cerebral infarctions after open heart surgery, including:

• Individualized blood pressure management to optimize cerebral perfusion during the perioperative period 2
• The use of cerebral protection systems, such as the Sentinel cerebral protection system, which has been shown to be safe and feasible in high-risk patients 5
• Careful assessment of indications and timing of surgery to prevent recurring stroke in patients with a history of ischemic stroke or transitory ischemic attack 2