Mitral valve repair or replacement

Mitral 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 and mechanism of lesion (MS vs MR, primary vs secondary) -LV size and systolic function -Pulmonary HTN, RV function -Chronic atrial fibrillation -Thromboembolism risk (LA thrombus) -Concomitant procedures (CABG, MAZE, multi valves)
Intraoperative	-Hemodynamic goals (MS vs MR) -Full heparinization before CPB -Myocardial protection and de-airing -Conduction disturbances -Weaning from CPB: LV/RV function, valve seating, gradients
Postoperative	-RV failure -SAM -Atrial fibrillation -Low cardiac output syndrome -Bleeding
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Mitral valve repair or replacement is performed for severe mitral regurgitation (MR), mitral stenosis (MS), or mixed disease. Repair is preferred when possible because it preserves annular-ventricular continuity, maintains LV geometry, improves long-term survival, and avoids prosthetic complications. Replacement (SMVR) is performed when repair is not durable or technically feasible (severe calcifications, rheumatic disease, extensive endocarditis).

Overview

Indications

• Symptomatic severe primary (degenerative) MR
• Symptomatic severe MS
• Severe secondary (functional) MR with persistent symptoms despite GDMT
• Severe MR with LV dilation or LV dysfunction
• Recurrent MR after primary repair
• Endocarditis with structural destruction
• Concomitant need during CABG or other valve surgery

Unlike Transcatheter mitral valve repair/replacement, SMVR allows:

• Complete annular debridement
• Abscess debridement
• Annular enlargement
• Leaflet resection and chordal reconstruction
• Preservation of subvalvular apparatus
• Concomitant procedures like MAZE, left atrial appendage excision, tricuspid repair, or CABG
• Durability advantage in primary MR in low risk patients

Transcatheter mitral valve repair/replacement (TMVR) is preferred in:

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

Surgical procedure

Most commonly performed via median sternotomy, but minimally invasive approaches exists

After systemic heparinization (ACT > 480 seconds), cardiopulmonary bypass is established with aortic and right atrial (or bicaval) cannulation. Aortic cross-clamp is applied, and myocardial protection is achieved through cold blood cardioplegia delivered either through aortic root (antegrade) and/or coronary sinus (retrograde).

Left atriotomy (via interatrial groove or transseptal approach) is performed and mitral valve is directly inspected to determine mechanism of pathology.

Repair techniques include annuloplasty ring placement, leaflet resection, chordal replacement, or commissurotomy (MS).

Replacement involves native valve excision (preserving posterior leaflet, if possible, to maintain ventricular geometry). Mechanical or bioprosthetic valve is then implanted. Sutures are placed circumferentially around the annulus. Preservation of subvalvular apparatus reduces postoperative LV dysfunction.

Concomitant MAZE procedure frequently performed in patients with chronic atrial fibrillation and involves surgical ablation lines created in atria. This can be combined with left atrial appendage ligation or excision.

De-airing is critical due to open left atrium and TEE guidance before cross-clamp removal. After reperfusion and rewarming, patient is weaned from CPB.

Temporary epicardial pacing wires are routinely placed due to risk of conduction disturbances. After protamine administration and hemostasis, chest closure is performed.

Preoperative management

Patient evaluation

System	Considerations
Airway	-Prior sternotomy may limit neck mobility
Neurologic	-History of stroke, TIA, cognitive baseline
Cardiovascular	-Severity assessment (MS vs MR) -LV size and systolic function -LA size -RV function -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 Mitral Stenosis - Valve area < 1.0 cm2, mean gradient > 10mmHg, PAP > 50mmHg

Severe Mitral Regurgitation - EROA > 0.4cm2, regurgitant volume > 60mL, regurgitant fraction > 50%, vena contracta > 7mm

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/ARBs and 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

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

Induction and airway management

Severe mitral stenosis - standard IV induction acceptable with caution

• Maintain sinus rhythm
• Avoid tachycardia (goal HR 60-80)
• Avoid hypotension (maintain preload)
• Avoid sudden decrease in SVR
• Tachycardia shortens diastole -> worsens LV filling -> pulmonary congestion
• Loss of atrial contraction in MS can cause dramatic decrease in cardiac output

Severe mitral regurgitation - standard IV induction typically well tolerated

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

Positioning

• Supine
• Arms tucked

Maintenance and surgical considerations

Cardiopulmonary bypass:

• Full heparinization (ACT > 480sec)
• Aortic cross clamp
• Cardioplegia (antegrade +/- retrograde)
• Venting LV
• De-airing critical (LA is opened)

Complications during cross-clamp removal:

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

MAZE procedure

• Longer cross-clamp and CPB time
• Higher early conduction abnormalities and postoperative pacing requirements
• Left atrial appendage often ligated or excised

Post-bypass considerations

Be ready for:

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

Common issues:

• Systolic anterior motion (SAM)
• Pulmonary HTN
• RV dysfunction
• Residual gradient
• Paravalvular leak
• Atrial arrhythmias

TEE assessment:

• Valve assessment
  • Proper seating
  • Paravalvular leak
  • Mean gradient appropriate
  • Systolic anterior motion (SAM)
• Air
  • LA, LV apex, LVOT, ascending aorta
  • Air in coronaries -> immediate ST changes and RV dysfunction
• LV function
  • Global function
  • New RWMA
  • Afterload mismatch (chronic MR patients may develop acute LV dysfunction after repair due to sudden increase in afterload)
• RV function
  • RV dilation
  • TAPSE
  • Septal shift
  • Elevated PAP

Hypotension causes:

• SAM - LVOT obstruction, MR
• Vasoplegia - good EF, low SVR
• Ischemia/stunning or afterload mismatch - poor EF, LV function
• 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

• Atrial arrhythmias (large left atrium, surgical manipulation, MAZE procedure)
• Heart block (requiring pacing)
• Vasoplegia (CPB induced inflammatory state with low SVR despite normal EF)
• Low cardiac output syndrome (can be from ischemia, LV dysfunction, afterload mismatch, prosthesis-patient mismatch)
• Bleeding/re-exploration
• Stroke/neurological deficits (air embolism from LA opening)
• Acute kidney injury

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

Procedure variants

	Minimally invasive	MVR+MAZE	MVR+CABG	Redo	Commando
Unique considerations	-Peripheral cannulation -Lung isolation	-Possible LAA closure	-Higher ischemic risk -More inotropes need	Blood in room before incision	-Prolonged bypass, vasoplegia -Massive transfusion -Mechanical circulatory support
CPB complexity/time	Higher	Higher, longer	Higher, longer	Very high	Extremely high
EBL	Lower	Similar	Higher	Higher	Very high
Potential complications	-Full sternotomy conversion -Less wound complications	-Atrial arrhythmia -Heart block	LCOS, bleeding	-Re-entry injury -Transfusion	-Pacemaker dependence -Very high bleeding, vasoplegia -Mortality risk