What anesthetic techniques are recommended for a patient with aortic stenosis undergoing surgery?

From the Guidelines

For patients with aortic stenosis undergoing surgery, a carefully controlled general anesthesia with invasive hemodynamic monitoring is recommended. The anesthetic approach should maintain normal sinus rhythm, adequate preload, systemic vascular resistance, and avoid tachycardia and hypotension, as emphasized in the 2021 ACC/AHA guideline for the management of patients with valvular heart disease 1.

Key Considerations

• Induction can be achieved with etomidate or carefully titrated propofol, combined with fentanyl or sufentanil.
• Maintenance typically involves a balanced technique using volatile agents with opioids.
• Avoid ketamine and pancuronium due to their sympathomimetic effects.
• Invasive arterial monitoring and central venous pressure monitoring are essential, with pulmonary artery catheterization considered for severe stenosis.
• Fluid management should be conservative but adequate to maintain preload.
• Vasopressors like phenylephrine should be immediately available to treat hypotension, as suggested by the guideline 1.

Rationale

The rationale behind these recommendations is to prevent hemodynamic compromise in aortic stenosis patients who have fixed cardiac output, are preload dependent, and rely on adequate diastolic filling time and systemic vascular resistance to maintain coronary perfusion and cardiac output. The 2021 guideline 1 and other studies 1 support the importance of careful anesthetic management and hemodynamic monitoring in patients with aortic stenosis undergoing noncardiac surgery.

Additional Guidance

For patients who meet indications for aortic valve replacement before noncardiac surgery but are considered high risk or ineligible for surgical AVR, options include proceeding with noncardiac surgery with invasive hemodynamic monitoring and optimization of loading conditions, percutaneous aortic balloon dilation as a bridging strategy, and transcatheter aortic valve replacement (TAVR), as discussed in the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery 1. However, the most recent and highest quality evidence from the 2021 ACC/AHA guideline 1 should be prioritized when making decisions about anesthetic techniques for patients with aortic stenosis.

From the FDA Drug Label

In patients whose intracranial pressure is already elevated, sodium nitroprusside should be used only with extreme caution. When sodium nitroprusside (or any other vasodilator) is used for controlled hypotension during anesthesia, the patient’s capacity to compensate for anemia and hypovolemia may be diminished. Extreme caution should be exercised in patients who are especially poor surgical risks (A.S.A. Class 4 and 4E).

The recommended anesthetic techniques for a patient with aortic stenosis undergoing surgery are not directly stated in the provided drug labels. However, it can be inferred that:

• Caution should be exercised when using vasodilators like sodium nitroprusside in patients with aortic stenosis, as they may exacerbate the condition.
• Phenylephrine may be used to maintain blood pressure in patients undergoing surgery with neuraxial or general anesthesia, but its use in patients with aortic stenosis is not explicitly addressed.
• Extreme caution should be exercised in patients who are especially poor surgical risks, which may include those with aortic stenosis 2.

From the Research

Anesthetic Techniques for Aortic Stenosis

The management of patients with aortic stenosis undergoing surgery requires careful consideration of anesthetic techniques to minimize the risk of cardiac complications.

• General anesthesia can be used in patients with aortic stenosis, but it may lead to hypotension and decreased cardiac output 3, 4.
• Neuraxial anesthesia, such as combined spinal-epidural anesthesia, can be a safe and efficient anesthetic method for patients with asymptomatic severe aortic stenosis undergoing spinal surgeries 5.
• The choice of anesthetic technique and agent should be optimized to manage the patient's condition, taking into account the severity of the aortic stenosis and the type of surgery being performed 4, 6.

Hemodynamic Management

Hemodynamic management is crucial in patients with aortic stenosis undergoing surgery.

• Dobutamine infusion can increase cardiac index, but its effect on stroke volume index is highly variable and depends on baseline left ventricular ejection fraction 3.
• Fluid bolus can increase cardiac index and stroke volume index, but it may also lead to an increase in pulmonary capillary wedge pressure, particularly in patients with a larger left atrial volume index 3.
• Vasodilators, such as nitroprusside, can improve myocardial performance in patients with severe aortic stenosis and left ventricular dysfunction, but their use requires careful monitoring and caution 7.

Perioperative Management

Perioperative management of patients with aortic stenosis requires careful attention to detail to minimize the risk of cardiac complications.

• Anesthetic management should be adjusted to maintain left ventricular preload and afterload, and to keep the patient in sinus rhythm 6.
• Close monitoring of the patient's hemodynamic status and cardiac function is essential during the perioperative period 3, 6.
• Temporary pacing may be necessary in patients who develop atrioventricular block or other cardiac rhythm disturbances during the perioperative period 6.