What anaesthetic agents should be avoided in patients with aortic stenosis?

Anaesthetic Agents to Avoid in Patients with Aortic Stenosis

In patients with aortic stenosis, anaesthetic agents that cause significant vasodilation, myocardial depression, or tachycardia should be avoided as they can precipitate hemodynamic collapse. 1

Hemodynamic Considerations in Aortic Stenosis

Aortic stenosis presents unique hemodynamic challenges that influence anaesthetic management:

• The fixed obstruction to left ventricular outflow creates a pressure-overloaded, hypertrophied left ventricle with reduced compliance 2
• Patients are dependent on adequate preload, sinus rhythm, and sufficient systemic vascular resistance 2
• Coronary perfusion may be compromised due to increased myocardial oxygen demand and reduced diastolic perfusion time 1

Specific Agents to Avoid

Vasodilators

• Avoid potent vasodilators such as sodium nitroprusside, nitroglycerin, and hydralazine as they can cause precipitous drops in systemic vascular resistance leading to hypotension and decreased coronary perfusion 2, 1
• Avoid high-dose or rapid administration of ACE inhibitors and ARBs as they can cause significant vasodilation 2

Negative Inotropes

• Avoid high concentrations of volatile anaesthetics (particularly isoflurane, desflurane) which can cause myocardial depression and vasodilation 1, 3
• Avoid propofol in large bolus doses as it can cause significant vasodilation and myocardial depression 1

Agents Affecting Heart Rate

• Avoid medications that cause tachycardia (e.g., pancuronium, atropine, glycopyrrolate in high doses) as increased heart rate reduces diastolic filling time 2, 1
• Avoid medications that cause significant bradycardia unless specifically indicated, as this may reduce cardiac output in patients with severe AS 2

Regional Anaesthesia Considerations

• Avoid high neuraxial blocks (high spinal or epidural) due to the risk of significant sympathetic blockade causing vasodilation and hypotension 4
• Avoid rapid administration of local anaesthetics for neuraxial blocks; use dilute solutions with opioids instead 2

Preferred Anaesthetic Approach

• Etomidate is often preferred for induction due to its cardiovascular stability 1
• Opioid-based anaesthesia with careful titration of volatile agents is generally well-tolerated 1
• Phenylephrine or norepinephrine are preferred vasopressors as they maintain systemic vascular resistance without adversely affecting ventricular function 2
• Short-acting beta-blockers (e.g., esmolol) may be useful to control tachycardia if needed 1

Special Considerations

• Invasive hemodynamic monitoring is essential for patients with moderate to severe aortic stenosis 2, 1
• Transesophageal echocardiography is valuable for monitoring ventricular filling and function 2
• Maintain normal sinus rhythm; treat arrhythmias promptly 2
• Careful titration of fluids to maintain adequate preload without causing pulmonary congestion 2, 1

Postoperative Management

• Continue invasive hemodynamic monitoring in the immediate postoperative period 1
• Maintain stable hemodynamics and avoid rapid changes in volume status 2
• Consider intensive care unit monitoring for 48-72 hours postoperatively for high-risk patients 2