Aortic valve repair or replacement

Aortic valve repair or replacement

Anesthesia type	General
Airway	ETT
Lines and access	PIV, Arterial line, Central line, +/- PA catheter
Monitors	Standard ASA, arterial line BP, CVP +/- PAP, TEE, NIRS
Primary anesthetic considerations
Preoperative	-Severity of lesion (AS vs AR) -Symptoms (syncope, angina, dyspnea) -LV function and size (hypertrophy) -Coronary disease (concomitant CABG) -Pulmonary HTN -Rhythm (atrial fibrillation)
Intraoperative	-Hemodynamic goals (AS vs AR) -Full heparinization before CPB -Myocardial protection and de-airing -Conduction disturbance after valve replacement -Weaning from CPB: LV/RV function, valve seating, gradients
Postoperative	-Vasoplegia -Low cardiac output syndrome -Conduction abnormalities -Bleeding -Early vs delayed extubation
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Aortic valve repair or replacement is performed for aortic stenosis (AS), aortic regurgitation (AR), or mixed disease. It is performed with sternotomy under cardiopulmonary bypass (CPB). Surgical aortic valve replacement (SAVR) involves excision of the native valve and implantation of a mechanical or bioprosthetic prosthesis.

Indications:

• Symptomatic severe AS
• Severe AR with LV dilation or dysfunction
• Endocarditis with structural destruction
• Concomitant CABG requirement
• Root/ascending aortic pathology

Unlike Transcatheter aortic valve replacement, SAVR allows:

• Complete annular debridement
• Abscess repair
• Annular enlargement
• Root replacement
• Concomitant multivessel CABG
• Durability advantage in younger patients

Transcatheter aortic valve replacement (TAVR) is preferred in:

• Elderly patients
• High or prohibitive surgical risk
• Frailty or hostile chest

Preoperative management

Patient evaluation

System	Considerations
Neurologic	-Syncope history (critical AS) -Carotid disease (stroke risk)
Cardiovascular	-AVA, mean gradient, velocity (severity) -LVEF, LVH vs LV dilation (pressure or volume overload) -Diastolic dysfunction (preload sensitivity) -pulmonary HTN (RV risk post bypass) -CAD (concomitant CABG) -Rhythm (atrial fibrillation)
Pulmonary	-Restrictive lung physiology (HF/sternotomy) -COPD (prolonged vent weaning)
Gastrointestinal	-Dysphagia, esophageal/GI tract surgeries (TEE)
Hematologic	-Anticoagulation use, blood products available
Renal	-Baseline Cr, kidney disease (CPB AKI risk)
Endocrine	-DM
Other	-Endocarditis (longer CPB)

Echocardiography

Severe Aortic Stenosis - AVA < 1cm2, mean pressure gradient > 40mmHg, peak velocity > 4m/s

Severe Aortic Regurgitation - vena contracta > 6mm, pressure half-time < 200ms, holodiastolic flow reversal in the descending aorta > 20cm/s

Conduction System Risk

AV node and bundle of His lie near membranous septum, so sutures placed in annulus can damage conduction tissue. This is higher risk with pre-existing RBBB, heavy annular calcification, and endocarditis with abscess.

Permanent pacemaker rate: ~3-8%

Labs and studies

• CBC, CMP, PT/PTT
• T&C pRBC FFP
• TTE/TEE, cardiac cath, EKG, CXR

Operating room setup

• Have at least 5-8 channels for infusions
  • Epinephrine, norepinephrine, carrier, insulin (some institutions use phenylephrine in place of norepi)
  • Consider TXA, ketamine, dexmedetomidine, cefazolin
• Drugs:
  • Emergency medications (bolus):
    • epinephrine, atropine
    • Other bolus vasopressors (e.g. vasopressin, phenylephrine, norepinephrine)
    • +/- esmolol, nicardipine, and nitroprusside
  • Heparin, protamine, calcium
  • +/- Magnesium
• Perfusion technician should be available along with cell saver
• Fluid warmer
• Triple transducers primed and zeroed
• Internal defibrillator/pacer available in room
• TEE machine with appropriately sized probe

Patient preparation and premedication

• Continue beta blockers, statins, antianginals
• Hold ACE inhibitors, DOACs per protocol

Regional and neuraxial techniques

• Pre-Op: Erector Spinae Plane Block
• Intra-op: Parasternal Intercostal Block - after sternal wound closure and prior to emergence

Intraoperative management

Monitoring and access

• Arterial line (usually before induction)
• Central access (usually double stick with single lumen and cordis)
• +/- PA catheter (in severe LV dysfunction, pulmonary HTN, or RV dysfunction)
• TEE

Induction and airway management

Severe aortic stenosis - slow, controlled induction

• Maintain SVR
• Maintain sinus rhythm
• Avoid tachycardia (goal HR 60-80)
• Avoid hypotension
• Avoid high PEEP initially
• Hypotension/decrease SVR -> decrease coronary perfusion -> ischemia -> acute LV failure

Severe aortic regurgitation - standard induction acceptable

• Avoid bradycardia (goal HR 80-100)
• Avoid sudden increase in SVR
• Bradycardia -> increase regurgitant time -> decrease forward flow

Maintenance and surgical considerations

Cardiopulmonary bypass:

• Full heparinization (ACT > 480sec)
• Aortic cross clamp
• Cardioplegia (antegrade +/- retrograde)
• Venting LV
• De-airing critical (air embolism risk)

Complications during cross-clamp removal:

• Air embolism
• Ventricular arrhythmia
• Acute RV failure (air to RCA)

Post-bypass considerations

Be ready for:

• Inotropes (epinephrine, milrinone, dobutamine)
• Vasopressors (norepinephrine, vasopressin)
• Pacing (temporary wires placed)

Common issues:

• LV dysfunction
• RV dysfunction
• Residual gradient
• Paravalvular leak
• Complete heart block

TEE assessment:

• Valve assessment
  • Proper seating
  • Paravalvular leak
  • Central regurgitation
  • Leaflet mobility
  • Mean gradient appropriate
• Air
  • LV apex, LVOT, Non-coronary cusp, Pulmonary veins
  • Air in coronaries -> immediate ST changes and RV dysfunction
• LV function
  • Global function
  • New RWMA
• RV function
• Aorta
  • Aortic root
  • Cannulation sites
  • Dissection flap
  • Hematoma

Hypotension causes:

• Vasoplegia - good EF, low SVR
• Ischemia/stunning - poor EF
• RV failure - high CVP, dilated RV
• Prosthesis mismatch - high gradient across valve
• Air embolism - ST changes

Emergence

Often wean to extubation in ICU

Postoperative management

Disposition

• Cardiac ICU

Pain management

• Parasternal block
• Multimodal analgesia

Potential complications

• Complete heart block (AV node lies near membranous septum and can be damaged during annular suturing)
• Atrial fibrillation
• Vasoplegia (CPB induced inflammatory state with low SVR despite normal EF)
• Low cardiac output syndrome (can be from ischemia, LVH stiffness, afterload mismatch, prosthesis-patient mismatch)
• Bleeding/re-exploration
• Stroke (aortic manipulation, calcified debris, air embolism)
• Acute kidney injury

Mechanical valve is more durable but carries higher bleeding risk and requires lifelong anticoagulation

Procedure variants

	Minimally invasive	AVR+CABG	Redo	Bentall	Commando
Unique considerations	-Peripheral cannulation -Retrograde perfusion -Possible lung isolation	-Higher ischemic burden -More inotropes -Transfusion	Blood in room before incision	-Coronary button reimplantation risk -Large aortic manipulation -Possible circulatory arrest	-Prolonged bypass, vasoplegia -Massive transfusion -Mechanical circulatory support
CPB complexity/time	Moderate	Higher, longer clamp	Higher	Higher, prolonged clamp	Very high, prolonged CPB
EBL	Moderate	Higher	High	High	Very high
Potential complications	-Stroke risk (retrograde perfusion) -Full sternotomy conversion	MI, LCOS, AF, bleeding	-Severe hemorrhage -Graft injury	-Stroke, coronary ischemia -Massive hemorrhage	-Pacemaker dependence -Very high bleeding, vasoplegia -Mortality risk