Mitral valve disease – Mitral Regurgitation

Mitral valve fails to close completely, causing blood to flow back into the left

atrium during ventricular systole of multiple aetiology

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Anatomy of Mitral valve apparatus

• 45 year old women diagnosed c/o chronic mitral regurgitation posted for abdominal hysterectomy

• Natural history• Pathophysiology• Preoperative assessment• Perioperative management

Clinical presentation

• Depends on EtiologySeverity

of regurgitation Left ventricular functionPulmonary hypertensionAtrial fibrillationMixed valvular lesionCoronary artery disease & Hypertension

Etiopathology

• Valve leaflet Rheumatic Carditis SequlaeMyxomatous DegenerationCongenital Cleft Leaflet Marfan Syndrome Infective Endocarditis HOCM

Mitral valve prolapse (MVP)

Etiopathology

• Chordae Tendinae Rheumatic

Ischemic• Papillary Muscles

Ischemic• Annulus

Calcification - elderly patients Dilatation - functional MR

Pathophysiology

Regurgitation of LV SV• R

educed CO & LA dilatation

LA dilatation• A

trial fibrillation, Clot, Reactive PHT& Right heart failure

LV volume overload • L

VH (concentric) & LV dilatation

LV failure • P

ulmonary edema, systemic hypotension

Assessment of severity of MR

• Symptoms severity• Presence of PHT• Physical signs of CHF• ECHO

Symptoms Depends on Atrial compliance

• Normal compliance – pulmonary congestion symptomsExertional dyspnea (NYHA )

Orthopnea Right heart failure symptoms

ankle edema upper abdominal pain

ascites • Increased compliance - low cardiac output symptoms

easy fatigue • Palpitations (Atrial fibrillation)• Embolic symptoms or past history

Ejection fraction (EF) & MR

• Fraction of ventricular end diastolic volume ejected EF = EDV- ESV/EDV

• Inspiteof LV dysfunction EF may be normal in range• LA acts as low resistance pathway during systole, EF

overestimates LV function• LV dysfunction defined as EF< 60% (AHA Guidelines)

Echocardiographic classification of MR

Echocardiographic assessment of regurgitant lesions by color – flow Doppler

Grade Description Criterion

0 None No regurgitation into receiving chmber

1+ Mild Regurgitant flow limited to area near valve

2+ Mild to moderate Regurgitant flow occupies up to 1/3 of LA

3+ Moderate to severe Regurgitant flow occupies up to 2/3 of LA

4+ Severe Regurgitant flow occupies most of receiving LA & flow reversal in pulmonary veins

Premedication

• Standard doses of any common agents well tolerated & desirable in normal ventricular function

• Poor ventricular function – doses proportional to severity of ventricular function

• Usual medication on the morning of surgery• Supplemental O2 – PHT or pulmonary disease• Antibiotic prophylaxis ? IE , ? Surgical • Anticoagulation management

Monitoring

• Depends on LV function & procedure• Full hemodymaic monitoring – if plan for afterload

reduction with vasodilators• Color- flow Doppler TEE

quantify severity guides therapeutic interventions in severe lesions

• Pulmonary artery pressure monitoring

Anesthetic management objectives

• Tailored to severity of regurgitation jet, LV function• Avoid factors exacerbating the regurgitation

Bradycardia - ↑↑ LV end diastolic volumemitral annular dilatation

Acute rise in SVR Excess volume expansion – dilates LVMyocardial depression

• Prevent & promptly treat AF

Hemodynamic goalsMaintain forward systolic flow

Full, Fast & Vasodilated

Preload

• Augment LV preload prior to induction• Remember MR is dynamic• Excess ventricular distension →annular dilatation →

worsens MR

Heart rate & Rhythm

• Bradycardia detrimental ↑duration of systole→ prolongs regurgitation ↑ diastolic filling→ LV distension

• Sinus rhythm preferred LV filling less depends on atrial kick as compared to MS

Contractility

• EF underestimates LV systolic function • Avoid myocardial depression • How to manage hypotension?

Manipulate volume & heart rate• Persistent hypotension → inotropic support

DobutamineLow Dose EpinephrineMilrinone

Afterload

• Low SVR maximizes forward cardiac outputAdequate anesthetic depthSystemic vasodilatorsInodilatorsIABP – acute MR

• Alpha 1 agonists worsens MRincreases SVR & reflex bradycardia

• Temporary use of Ephedrine bolus preferable

Pulmonary hypertension

• PAP & PVR elevated in acute and chronic MR• Secondary RV dysfunction• Avoid factors increasing PVR

Hypoxia Hypercapnia Acidosis

High tidal volume High PEEP

Factors affecting Mitral valve repair

• Acute vs chronic MR• Patient’s symptom severity• Left ventricular function• Severity of mitral regurgitation• Feasibility of successessful repair• Combined valvular lesions• Complications of chronic MR

Choice of agents

• Preserved ventricular function – most anesthetic techniques tolerated well

• Spinal, epidural anesthesia tolerated (avoid bradycardia)

• Ventricular dysfunctionsensitive to volatile agentsopioid based anesthetic (avoid bradycardia)pancuronium with opioids useful

Symptomatic patients NYHA 2,3 & 4

Indicated 1. Acute severe MR (class 1)2. Absence of severe LV dysfunction(class1)3. Severe LV dysfunction & MV repair high likely (2a)4. Functional MR ,severe LV dysfunction on maximum

medical therapy includes biventricular pacing (2b) (severe LV dysfunction = EF < 30% )

Indications for Asymptomatic patients

• Chronic severe MR and mild to moderate LV dysfunction (class1)

• Chronic sever MR with normal LV function High likely successful repair (2a)New onset atrial fibrillation (2a)Pulmonary hypertension (2a)

• Not indicated (class 3)Normal LV function & doubt about feasibility

of repairMild or moderate MR

Mitral regurgitation complicating Pregnancy

• Typically well tolerated due to favorable loading conditionsincreased blood volume, heart rate & low SVR

• Increased risk of AF ECG monitoring during laborAcute AF – promptly control ventricular rate

• Hypercoagulability , increases risk of systemic embolismAnticoagultion

New onset AF, H/o embolism & Cardioversion

Management of parturient

• High SVR during labor – poorly toleratedPain, Expulsive efforts & aortic compression

• Prevent & treat high SVR Epidural analgesia

Results in low venous return Left lateral tilt

• SAB tolerated by pt’s with mild to moderate MR• Vasopressor of choice

Chronotrophic effect of Ephedrine benefits

Thank you

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