Mitral Regurgitation (MR)

 

 

Considerations

 

  • ↑ risk of perioperative cardiac complications (MI/CHF)

  • Hemodynamic alterations associated with MR:

    • Left atrial volume overload & ↓ forward cardiac output (CO)

    • Potential for LV dysfunction (from overload)

    • Potential for arrhythmias (atrial fibrillation commonly) due to LA dilatation

    • Potential for pulmonary hypertension leading to RV dysfunction

  • Acute MR: sudden LA & LV overload without compensatory hypertrophy leading to decreased forward CO & simultaneous pulmonary congestion

  • Comorbid disease:

    • Coronary artery disease

    • Atrial fibrillation

    • Other valvular lesions (MS, AI)

    • Connective tissue diseases (SLE, RA, Marfan’s)

    • Endocarditis

  • Management of medical therapy:

    • ACE inhibitors, beta-blockers, digoxin, calcium channel blockers

 

 

Goals

 

  • Maintain forward flow & ↓ regurgitant fraction:

    • Preload: maintain preload but avoid overload (↑ risk for CHF)

    • Rate: high-normal rate (80-100bpm) & avoid bradycardia (longer diastole = more regurgitation)

    • Rhythm: sinus rhythm preferred but not as critical as stenotic lesions 

    • Contractility: maintain or enhance contractility to improve forward flow & reduce regurgitant fraction by constricting mitral valve annulus 

    • Afterload: reduce afterload to enhance forward flow 

  • Avoid ↑ in pulmonary vascular resistance to mitigate right heart failure (avoid hypoxia, hypercarbia, acidosis, pain)

 

 

Pregnancy Considerations 

 

  • Goals:

    • Prevent an ↑ in SVR

    • Maintain a normal to slightly elevated heart rate

    • Maintain sinus rhythm

    • Aggressively treat acute atrial fibrillation

    • Avoid aortocaval compression

    • Maintain venous return

    • Prevent an ↑ in central vascular volume

    • Avoid myocardial depression during general anesthesia

    • Prevent pain, hypoxemia, hypercarbia, & acidosis (may ↑ PVR)

  • Monitoring:

    • Invasive monitoring rarely required unless severe mitral regurgitation 

  • Anesthetic options:

    • Epidural preferred for vaginal delivery or cesarean section 

    • If GA used, give attention to the maintenance of adequate heart rate & ↓ afterload

    • Acute atrial fibrillation must be treated promptly & aggressively; hemodynamic instability warrants the immediate performance of cardioversion

 

Further Reading 

  • Stoelting's Anesthesia and Co-Existing Disease, 7th Edition, Chapter 6: Valvular Heart Disease

  • Chestnut's Obstetric Anesthesia, 6th Edition, Chapter 41: Cardiovascular Disease