Risk factors associated with perioperative strokes

科室遇到了一例口腔癌术后发生大面积脑梗的患者，55岁男性，有吸烟史，无高血压及其他心脑血管病史。看了下手术的信息：牙龈颌颈联合根治术，手术时长6小时余。

这种情况也是第一次遇到，所以晚上进行了一下学习和总结。

Risk Factors of Perioperative Strokes (Ranked by Contribution/Danger)

1. Age: ≥70 years significantly increases stroke risk due to reduced vascular resilience and comorbidities.
2. History of Stroke: Prior ischemic stroke is the strongest predictor of recurrence.
3. Atrial Fibrillation: Highly associated with embolic strokes.
4. Vascular Diseases: Includes carotid stenosis, peripheral vascular disease, and coronary artery disease.
5. Hypertension: Chronic or uncontrolled hypertension predisposes to vascular events.
6. Diabetes Mellitus: Contributes to microvascular damage and thrombosis risk.
7. Cancer: Hypercoagulability associated with malignancy increases embolic risk.
8. Smoking: Enhances vascular damage and thrombosis potential.
9. Renal Impairment: Correlates with systemic vascular dysfunction.
10. Obesity: Adds stress to cardiovascular and vascular systems, increasing risks.

Operation-Associated Factors Contributing to Perioperative Strokes

1. Type of Surgery:

• High-risk surgeries: Vascular, head and neck, and procedures requiring beach-chair positioning.
• Surgeries prone to embolism or hypoperfusion risks.

2. Blood Pressure Management:

• Intraoperative Hypotension (IOH): Prolonged MAP drops >30% from baseline.
• Postoperative Hypotension: Often overlooked but equally dangerous.

3. Anesthesia:

• General anesthesia may impair autoregulation.
• Regional anesthesia may have lower risk if patient-specific factors permit.

4. Duration of Surgery:

• Longer surgeries increase exposure to systemic stress and hypotension.

5. Inflammatory Response:

• Surgery-induced hypercoagulability and inflammation exacerbate vascular risks.

Reasons for Delayed Detection and Treatment of Perioperative Strokes

1. Subtle Symptoms: Early signs like confusion or weakness may mimic anesthesia effects or delirium.
2. Inadequate Neurological Monitoring: Routine postoperative care does not prioritize neurological assessments.
3. Postoperative Monitoring Gaps: Less rigorous monitoring compared to intraoperative care.
4. Overlap with Common Postoperative Issues: Symptoms like altered mental state or hypotension are often attributed to non-neurological complications.
5. Limited Imaging Access: Diagnostic imaging (e.g., CT or MRI) may be delayed due to logistical challenges.
6. Undertrained Staff: Surgical teams may not promptly recognize evolving neurological deficits.

Suggested Prevention Measures for Operation-Associated Perioperative Strokes

1. Preoperative:

• Identify high-risk patients via history and imaging.
• Optimize management of hypertension, diabetes, and atrial fibrillation.
• Delay elective surgeries for at least 3 months after a recent stroke.
• Consider carotid revascularization for symptomatic high-grade stenosis.

2. Intraoperative:

• Maintain MAP within 20% of baseline.
• Avoid prolonged IOH, especially MAP drops >30%.
  • Use advanced monitoring tools (e.g., cerebral oximetry) for high-risk cases.
  • Minimize surgical duration and manage anesthesia depth carefully.

3. Postoperative:

   • Rigorous monitoring for hypotension, arrhythmias, and neurological changes.
   • Continue anticoagulation therapy for atrial fibrillation when safe.
   • Address systemic inflammatory responses effectively.

4. General:

   • Multidisciplinary approach involving surgeons, anesthesiologists, and neurologists.
   • Continue statin therapy to improve vascular resilience.
   • Maintain glucose levels in the 7.8–10 mmol/L range.

Differences Between the 20% Rule and Controlled Hypotension

Aspect	20% Rule	Controlled Hypotension
Goal	Protect cerebral and end-organ perfusion.	Minimize surgical bleeding and improve visibility.
Population Focus	High-risk patients (e.g., prior stroke).	General patients undergoing bleeding-prone surgeries.
BP Target	MAP ≥ 80% of baseline MAP.	MAP ~50–65 mmHg (varies by surgical context).
Risk Tolerance	Avoid prolonged or excessive hypotension.	Accept mild, short-duration hypotension.
Cerebral Perfusion	Prioritized to avoid ischemia.	Accepts temporary reductions for low-risk cases.
Duration	Sustained throughout surgery.	Temporary and reversible during specific phases.
Applicability	High-risk cerebrovascular patients.	Patients undergoing surgeries like head and neck or orthopedic procedures.

Balancing the Two: For high-risk patients, prioritize the 20% rule while allowing brief, carefully monitored hypotensive episodes if needed for surgical control. Advanced monitoring and inter-team communication are essential to achieving both aims effectively.

References:

1. Bijker JB, Persoon S, Peelen LM, Moons KG, Kalkman CJ, Kappelle LJ, van Klei WA. Intraoperative hypotension and perioperative ischemic stroke after general surgery: a nested case-control study. Anesthesiology. 2012 Mar;116(3):658-64. doi: 10.1097/ALN.0b013e3182472320. PMID: 22277949.
2. Ng JL, Chan MT, Gelb AW. Perioperative stroke in noncardiac, nonneurosurgical surgery. Anesthesiology. 2011 Oct;115(4):879-90. doi: 10.1097/ALN.0b013e31822e9499. PMID: 21862923.
3. And others.