What is the recommended anesthesia management for patients with aortic stenosis?

Anesthetic Management of Aortic Stenosis

Primary Hemodynamic Goals

The fundamental principle in managing aortic stenosis anesthesia is preventing prolonged hypotension while maintaining adequate preload, normal sinus rhythm, and avoiding tachycardia. 1 These patients have hypertrophied, non-compliant ventricles that depend critically on atrial kick and adequate diastolic filling time. 1

Critical Hemodynamic Targets:

• Maintain preload: Patients require adequate ventricular filling due to decreased ventricular compliance from hypertrophy 1
• Preserve sinus rhythm: Loss of atrial kick can precipitate acute decompensation 1
• Avoid tachycardia: Reduces diastolic filling time and coronary perfusion pressure 1
• Prevent hypotension: Systemic hypotension is poorly tolerated and can lead to coronary ischemia and death 1
• Maintain afterload: Adequate systemic vascular resistance ensures coronary perfusion 1

Preoperative Risk Assessment

All patients require echocardiographic quantification of stenosis severity, left ventricular function, and pulmonary artery pressures before proceeding. 1 Identify high-risk features during preoperative evaluation: depressed ejection fraction, elevated pulmonary pressures, significant mitral or tricuspid regurgitation, incomplete revascularization, collateral-dependent circulation, chronic lung disease, heart failure, and acute/chronic kidney disease. 2

Decision Algorithm for Noncardiac Surgery:

• Asymptomatic severe AS (valve area <1.0 cm²) with normal LVEF: Proceed with noncardiac surgery using appropriate monitoring 1
• Symptomatic severe AS: Requires valve intervention before elective noncardiac surgery to avoid prohibitive mortality 1
• Emergency surgery with uncorrected severe AS: Proceed with cardiovascular anesthesiologist involvement and maximal hemodynamic optimization 1

Do NOT perform prophylactic valve replacement before noncardiac surgery in asymptomatic severe AS—risk-benefit favors proceeding with hemodynamic optimization. 1

Anesthetic Technique Selection

For TAVR Procedures:

Conscious sedation is increasingly preferred over general anesthesia for transfemoral TAVR in experienced centers. 2 Observational studies demonstrate that conscious sedation compared to general anesthesia results in fewer requirements for inotropes/vasopressors, shorter hospital stays, shorter procedural times, and earlier mobilization. 2 An additional advantage is prompt detection of adverse neurological events. 2

However, this approach should only be used in highly experienced centers, not as an initial starting strategy, and only via the transfemoral approach. 2 Transapical or other non-transfemoral approaches require general anesthesia. 2

For Noncardiac Surgery:

• General anesthesia: Well tolerated when agents are chosen to maintain sinus rhythm and normotension 1
• Regional anesthesia: May be preferable for peripheral procedures as it avoids hemodynamic instability of general anesthesia induction 1
• Regional techniques contraindicated: In patients at risk of neuraxial hematoma from thienopyridine antiplatelet therapy, low-molecular-weight heparins, or significant anticoagulation 2

Airway Management:

Perform baseline airway evaluation focusing on ease of emergent intubation during cardiovascular compromise, particularly considering equipment obstruction from C-arm positioning. 2 For transapical TAVI, double-lumen tubes or single-lung ventilation are typically not required. 2

Intraoperative Monitoring Requirements

Invasive arterial pressure monitoring is mandatory in one or more sites. 2, 1 For thoracic aortic procedures, arterial pressure must be monitored proximal to aortic cross-clamping sites. 2

Additional Monitoring:

• Central venous pressure monitoring: Reasonable for optimization of loading conditions 1
• Pulmonary artery catheter: May be helpful in patients with poor ventricular function, though not universally required 2, 1
• Transesophageal echocardiography: Reasonable for all open surgical repairs and can guide hemodynamic management 1; used routinely for TAVR under general anesthesia to confirm diagnoses, detect complications, and assess valve positioning 2
• Temperature monitoring: At least 2 locations estimating brain/core and visceral temperature for thoracic aortic procedures 2

Pharmacologic Management

Vasopressor Selection:

Phenylephrine or norepinephrine are preferred agents to maintain systemic vascular resistance and coronary perfusion. 1 These pure alpha-agonists or combined alpha/beta-agonists preserve afterload without excessive tachycardia.

Inotropic Support:

Research demonstrates that in AS patients under general anesthesia, dobutamine increases cardiac index primarily through heart rate elevation rather than stroke volume augmentation. 3 The effect on stroke volume is highly variable and associated with baseline LVEF—patients with higher preoperative EF and larger decreases in stroke volume after induction show greater stroke volume increases with dobutamine. 3

Fluid Management:

Judicious fluid administration prevents pulmonary edema while maintaining adequate preload. 1 Fluid boluses increase both stroke volume and cardiac index but at the cost of increased pulmonary capillary wedge pressure, particularly in patients with larger left atrial volumes. 3

Anesthetic Agents:

Recent case series suggest remimazolam can safely maintain hemodynamic stability during TAVI induction (3.0 mg/kg/h) and maintenance (1.0 mg/kg/h), preserving cardiac output while minimizing cardiac suppression. 4, 5 However, transient hypotension may occur requiring low-dose vasopressor support. 5

Preparation for Complications

Cardiopulmonary bypass capability must be immediately available with predetermined access strategy. 2 For transfemoral TAVR, arterial cannulation can occur via the same access or through the delivery sheath. 2 For non-transfemoral cases, consider accessory femoral cannulation sites, axillary graft with venous cannula, or central cannulation. 2

Equipment Requirements:

The procedure location must have cardiopulmonary bypass machines, interventional cardiology equipment (balloon valvuloplasty, coronary balloons, stents, 0.014-inch wires), peripheral arterial balloons, covered stents for vascular complications, and vascular closure devices. 2

Bailout Strategies:

Pre-procedure discussion should cover valve-in-valve implantation for embolization, surgical AVR options (recognizing this may not be feasible for many TAVR patients), and management of major hemodynamic compromise from cardiac tamponade, coronary occlusion, severe acute aortic regurgitation, aortic rupture, or acute dissection. 2

Common Pitfalls to Avoid

• Do NOT use balloon aortic valvuloplasty as a bridge to noncardiac surgery in asymptomatic patients—it provides only short-term palliation with high complication rates 1
• Do NOT delay definitive treatment in symptomatic severe AS—medical management alone is rated "Rarely Appropriate" 6
• Do NOT assume low gradients mean less severe disease—reduced flow through severely stenotic valves produces deceptively low gradients representing advanced disease with poor prognosis 6
• Do NOT routinely change double-lumen tubes to single-lumen tubes after procedures complicated by significant upper airway edema or hemorrhage 2

Outcome Data

Modern anesthetic techniques have dramatically improved outcomes, with 30-day mortality of 2.1% in AS patients undergoing noncardiac surgery versus 1.0% in matched controls—a significant improvement from historical 13% mortality rates. 1 For TAVR procedures, appropriate anesthetic management with either general anesthesia or conscious sedation (in selected cases) results in excellent outcomes with all patients surviving to 30-day follow-up in reported series. 7