Mitral stenosis regurgitation pathophysiology anesthetic considerations for non cardiac surgery
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MITRAL STENOSIS & REGURGITATION Pathophysiology & Anesthetic considerations for non-cardiac surgery. Presenter: Dr Prashant Kumar. University College of Medical Sciences & GTB Hospital, Delhi. Mitral Stenosis. Mitral valve is present between LA & LV

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Mitral stenosis regurgitation pathophysiology anesthetic considerations for non cardiac surgery

MITRAL STENOSIS & REGURGITATIONPathophysiology & Anesthetic considerations for non-cardiac surgery

Presenter: Dr Prashant Kumar

University College of Medical Sciences & GTB Hospital, Delhi


Mitral stenosis
Mitral Stenosis

  • Mitral valve is present between LA & LV

  • Normal mitral valve orifice area (MVA): 4-6cm2

  • MVA <2.5cm2 leads to symptoms

  • Decrease in Mitral valve orifice area leading to chronic & fixed mechanical obstruction to LV filling is termed as MS.


Causes
Causes

  • Rheumatic Heart disease

  • SLE

  • Carcinoid syndrome

  • Active Infective Endocarditis

  • Left atrial myxoma

  • Congenital mitral stenosis

  • Massive Annular Calcification


Rheumatic mitral stenosis
Rheumatic mitral stenosis

  • More common in females (2/3rd of all pts)

  • Symptoms occur two decades after onset of Rheumatic fever

  • Age of presentation

    • Earlier in 20s-30s

    • Now in 40s-50s (slower progression)

  • Isolated MS in 40% cases of RHD

    • Remaining 60% cases associated with other valvular diseases- MR/AR


Patho physiology
Patho-physiology

  • Immunological disorder initiated by Group A beta hemolytic streptococcus.

  • Antibodies produced against streptococcal cell wall proteins & sugars react with connective tissues & heart; result in rheumatic fever and symptoms like

    • Carditis

    • Arthritis

    • Subcutaneous nodules

    • Chorea

    • Erythema marginatum


  • Chronic cardiac & valvular inflammation leads to cardiac & valvular pathology

  • Valvular pathology

    Rheumatic fever involving mitral valves

    Valve leaflet thickening and fusion of commissures

    Increased rigidity of valve leaflets

    Thickening, fusion and contracture of chordae & papillary heads

    Leaflet calcification (long standing MS)

    Progressive reduction in mitral valve orifice area

    Mitral Stenosis


Mechanical obstruction to left ventricular diastolic filling

Adaptative ↑ in LAP to maintain LV filling

-------------------------------------------------------------------------

LA enlargement ↑ in pulmonary venous pressure → ↑ in pulmonary arterial pressure*

Atrial fibrillation Transudation of fluid into pulmonary interstitial space

Thrombus formation

Systemic thrombo-embolism ↓ed pulmonary compliance ↑Work of breathing

Progressive dyspnoea on exertion/rest

Acute conditions like AF, Pregnancy, Pain, sepsis

(↑ HR/CO)

Acute ↑ in LAP

Pulmonary edema

↑ in pulmonary arterial pressure*--------→ Pulmonary arterial hypertrophy (Pulmonary HTN)

RV hypertrophy and dilatation

RV failure


Effect of ms on left ventricle

Pressure gradient between LA & LV filling

Effect of MS on left ventricle


Effect of heart rate
Effect of heart rate filling

  • Gorlin formula

    Valve area = Transvalvular flow rate (ml/s)

    K x PG1/2

    (PG: Transvalvular pressure gradient, mmHg)

    (K is a hydraulic-pressure constant =38)

  • Tachycardia shortens diastole more proportionately than systole

  • Decreases the overall time for transmitral flow,

  • In order to maintain CO, the flow rate per unit time must increase

  • Pressure gradient increase proportionate to square of flow rate

  • ↑LAP → Pulmonary venous congestion and symptoms.

  • So, patients with MS do not tolerate tachycardia.


Effect of atrial fibrillation in ms
Effect of Atrial fibrillation in MS filling

  • Increased chances of thrombus formation & systemic thrombo-embolism

  • Normally effective atrial contraction is important in LV diastolic filling

    • In presence of AF

      • Loss of effective atrial contraction

      • ↑ed ventricular rate (↓ed diastolic filling time)

        Impaired LV filling (↓ed LV preload)

        decreased cardiac output


Diagnosis
Diagnosis filling

  • Clinical presentation

    • Dyspnea, fatigue, orthopnea, PND, cough, hemoptysis,.

    • 10% patients have anginal type chest pain not attributable to CAD

    • Systemic thromboembolism (first symptom in 20% cases).

  • Physical examination

    • Low volume pulse

    • Sign & Symptoms of right sided heart failure - engorged neck veins, enlarged tender liver


  • Mitral facies filling

    ‘Pink purple patches on the cheeks, cyanotic skin changes from low cardiac output’

  • Cardiac auscultation

    • Opening snap

    • Rumbling diastolic murmur best heard at apex radiating to the axilla

    • Loud S2: pulmonary hypertension


  • ECG filling

    Broad notched P wave (left atrial enlargement)

    Atrial fibrillation


    Chest X-ray filling

    Normal to ↑ed cardiac shadow

    Straightening of the left heart of border and elevation of left main bronchus (left atrial enlargement)

    mitral calcification

    Evidence of pulmonary edema/ HTN

    LAA: Left atrial appendages, MPA: Main pulmonary artery, LPA: left pulmonary artery, RPA: Right pulmonary artery, Ao- Aortic knuckle (Ao)


    • Echocardiography filling

      • Anatomy/size of mitral valve & its appendages

      • severity of MS (area of orifice)

      • Size & function of ventricles

      • Estimation of pulmonary artery pressure

    • Cardiac catheterization and invasive measurement

      • Are almost never necessary

      • Reserved for situations ECHO sub-optimal/conflict with clinical presentation



    Guidelines
    Guidelines filling

    “Symptomatic MS (progressive dyspnoea on exertion, exertional pre-syncope, heart failure) is an active cardiac condition & pt should undergo evaluation & treatment before non cardiac surgery”

    • Emergency surgery

      Mild / Moderate MS

      • High risk

      • Continue medication

      • Proceed with surgery

    • Severe MS

      • Very high risk consent

      • Post- op ventilatory consent


    • Pre-operative Optimization of patient filling

      • Atrial fibrillation

        Sinus rhythm/control of ventricular rate

        1.Digoxin (emergent IV digitalization:- loading dose 0.25mg iv over 15 minutes followed by 0.1mg every hour till response occur or total dose of 0.5-1.0mg. Monitor ECG, BP, CVP; HR <60bpm- Stop)

        2. CCB (verapamil/diltiazem: 0.075-0.15mg/kg IV)

        3. β-blocker (esmolol: 1mg IV)

        4. Amiodarone (loading: 100mg IV, infusion: 1mg/min IV for 6 hrs. 0.5mg/min for next 18 hrs)

        5. Cardioversion in hemodynamic unstable patients


    • Pulmonary HTN/Edema/RVF filling

      1. Oxygen

      2. Diuretic

      Loop diuretics

      High dose deleterious

      Combine with vasodilator

      3. Digitalis

      4. Morphine (0.1mg/kg)


    ( fillingPre-operative Optimization of patient> Pulmonary HTN/Edema/RVF continued…)

    5. Vasodilators (NTG)

    Pulmonary vasodilation (↓PAP)

    Start from small dose (0.5–10 μg/kg/min)

    S/E: systemic hypotension

    6. Nesiritide

    Recombinant BNP (Brain natriuretic peptide)

    Arterial & venous dilatation

    Controls dyspnoea in Acute heart failure

    7. Myofilament calcium sensitizer (Levosimendan)

    Inodilators (↑es myocardial contractile strength, dilatation of systemic, pulmonary & coronary artery)


    ( fillingPre-operative Optimization of patient> Pulmonary HTN/Edema/RVF continued…)

    8. Inotropic agents

    Norepinephrine

    Dopamine

    Dobutamine

    9. Inodilators

    Amrinone

    Milrinone


    • Elective surgery filling

      • Mild/ moderate MS

        • Proceed with surgery after evaluation

        • Continue medications

      • Severe MS

        • Cardiology referral/surgical correction

        • Patients taken in optimized condition


    Management of anesthesia anesthetic goals
    Management of Anesthesia fillingAnesthetic goals


    Pre medication
    Pre medication filling

    • To decrease anxiety & any associated likelihood of adverse circulatory responses produced by tachycardia

    • Drug to control heart rate

    • Antibiotics (prophylaxis for infective endocarditis is no longer recommended) (Ref: Miller’s Anesthesia, 7th edition)


    Monitoring

    Asymptomatic filling

    Standard non-invasive

    ECG,

    HR

    NIBP

    Pulse-oxymetry

    Capnograph

    Temperature

    Symptomatic pts or major surgery

    Standard non-invasive

    Serial ABG

    Invasive monitoring

    IBP

    CVP/PAC

    Echocardiography (TTE/TEE)

    Cardiac catheterization

    Monitoring





    Post operative

    Management filling

    Monitoring

    Oxygen

    Pain relief: multimodal including neuroaxial opioids

    Intravenous fluids

    Anticoagulants

    Complication

    Pulmonary congestion/edema

    Thrombo-embolism

    Heart failure

    Post-operative



    Congestive heart failure
    Congestive Heart Failure patients with heart disease

    • Diuretics: loop diuretics (furosemide 20-40mg IV); S/E: Hypokalemia

    • Digoxin:

    Therapeutic plasma concentration level: 0.5-2.0ng/ml


    Clinical manifestation of digitalis toxicity patients with heart disease

    • Plasma level > 3ng/ml

    • Extra Cardiac: Anorexia, nausea, vomiting & abdominal pain (CTZ stimulation)

    • Cardiac: any type of atrial or ventricular arrhythmia, delayed conduction through AV Junction.

      • Atrial tachycardia with AV block is most common arrhythmia

      • Ventricular fibrillation is most frequently cause of death.

        Treatment of digitalis toxicity

    • Stop further dose

    • Correction of hypokalemia, hypomagnesemia, arterial hypoxemia

    • Drugs

      • Phenytoin (0.5-1.5mg/kg IV over 5min), lidocaine (1-2mg/kg IV), atropine (35-70µg/kg IV) for cardiac dysarrhythmia

      • Digiband (digoxin specific antibodies, Fab portion, IV preparation 40mg vial)

    • Insertion of a temporary artificial transvenous cardiac pacemaker


    Anticoagulant therapy
    Anticoagulant therapy patients with heart disease

    • Management of Patients on warfarin

      • Emergency surgery

        • Discontinue warfarin

        • Give vitamin K 0.5 – 2.0 mg IV

        • FFP 15 ml/kg repeat if necessary

        • Accept for surgery if INR <1.5

    • Elective surgery

      • Stop 3 days preoperatively

      • monitor INR daily

      • Give heparin when INR <1.5


    • Stop heparin 6 hours prior to surgery patients with heart disease

    • Check INR

    • Accept for surgery if INR <1.5

    • Restart heparin post-operatively as soon as possible

    • Both to be given for 2 – 3 days, stop heparin if INR 1.5 – 2.0.


    • Management of Patients on Heparin patients with heart disease

      • Emergency surgery

        • Consider reversal with IV protamine 1 mg for every 100 IU of heparin

      • Elective Surgery

        • Stop heparin 6 hours prior to surgery

        • Check INR, accept for surgery if INR <1.5

        • Restart heparin in post-op as soon as possible

          If patient is on LMWH, we rarely need to stop it.


    Summary of ms
    Summary of MS patients with heart disease

    • Is a low & fixed cardiac output condition

    • Stress condition like pregnancy, labour & sepsis, condition become worst- CHF, pulmonary edema, AF

    • Patients may be on diuretics, digitalis & anticoagulant therapy

    • Peri-operatively these patients have to be managed as per medications & guidelines

    • Tachycardia has to be avoided at any cost

    • Pulmonary vasculature resistance has to be reduced

    • Preload & afterload both should be maintained

    • NYHA I & II :- Epidural block or GA

    • NYHA III & IV :- GA preferred over epidural block


    Mitral regurgitation
    Mitral Regurgitation patients with heart disease



    • Functional mitral valve during systolic phase

      Structurally normal leaflets and chordae tendineae

      • Ischemic heart disease (Ischemic MR)

      • Idiopathic dilated cardiomyopathy

      • Mitral annular dilatation


    Pathophysiology of mr
    Pathophysiology of MR mitral valve during systolic phase

    Mitral regurgitation

    Systolic (Retrograde) ejection into LA

    Acute Chronic

    Volume overload in LA & LV ↓ed LV afterload (into LA)

    ↑ed LA, LV Pressure ↑ed LA/LV size/ compliance

    Pulmonary edema ↓ed Cardiac output LA dilatation ↓ed contractility

    AF ↓ CO

    Pulmonary congestion


    Acute mr
    Acute MR mitral valve during systolic phase

    Sudden onset MR

    Sudden increase in LV preload

    Enhanced LV contractility ↑ed LAP (acute)

    (LV size: N) (LA size: N)

    Ejection into LA & ↑ed Pulm vascul pressure

    systemic circulation

    ↓ cardiac output Pulmonary congestion/edema


    Chronic compensated mr
    Chronic compensated MR mitral valve during systolic phase

    • Slow development of MR

      Chronic LV overloading

      Eccentric LV hypertrophy LA dilatation

      ↑LV radius, ↑ed wall tension Maintenance of LAP

      Maintenance of LV systolic function Change in LV compliance

      (LVEDP maintained)

      After load/CO: maintained

      Gradual decline in LV systolic function

      Decompensated phase


    Decompensated phase
    Decompensated phase mitral valve during systolic phase

    Progressive LV dilatation

    Mitral annular dilatation ↑ed wall stress/afterload

    Increased regurgitation deteoration in LV syslolic

    & diastolic function

    ↑ed LAP

    Atrial enlargement Pulmonary congestion/edema/HTN

    Atrial Fibrillation RV dysfunction/failure


    Pathophysiology of ms with mr
    Pathophysiology of MS with MR mitral valve during systolic phase

    MSMR

    Obstruction of blood flow systolic (retrograde) ejection into LA

    from LA to LV during diastole

    Volume overload in LA Volume overload in LV

    ↓ed LV filling ↑ LAP LV dysfunction

    ↓ed CO

    ↓ed COLA dilatation

    ↑PVP/PAP

    (LV size/function: N)

    RV dysfunction


    Mr ms
    MR MS mitral valve during systolic phase


    Diagnosis1
    Diagnosis mitral valve during systolic phase

    • Clinical presentation

      • Fatigue, dyspnoea, orthopnoea/Systemic thrombo-embolism

    • Physical examination

      • Arterial pressure: N/↓

      • Pulse (Water Hammer pulse- ↓DBP, ↑ SBP)

      • Signs of RVF like ↑ JVP

      • Systolic thrill at apex (hyperdynamic circulation)

    • Cardiac auscultation

      • Holosystolic murmur

      • S1 is absent, soft or buried in the systolic murmur


    ECG mitral valve during systolic phase

    Non-specific findings

    Atrial fibrillation

    LA enlargement/LV hypertrophy

    Chest X-ray

    Left heart chamber enlargement

    Pulmonary congestion


    • Echocardiography mitral valve during systolic phase

      • Diagnosis/mechanism/severity of MR/MS

      • Impact on cardiac chamber size, pressure & function

      • Pulmonary artery pressure

      • Presence of thrombus

    • Cardiac catheterization with left ventriculography

      • invasive

      • Reserved for pts in whom ECHO is sub-optimal


    Severity of MR mitral valve during systolic phase


    Management of anesthesia
    Management of Anesthesia mitral valve during systolic phase

    Problems to be anticipated:

    • Pulmonary congestion/ edema

    • Atrial fibrillation/ thrombo-embolism

    • LV dysfunction: ↓ CO

    • Acute  in afterload following ET intubation & surgical stimulation  acute decompensation of LV

    • Bradycardia -  time for retrograde blood flow

    • Drug induced myocardial depression


    Anesthetic goals in MR mitral valve during systolic phasePrimary goals - Maintain forward systemic flow - Decrease the regurgitant fraction - Optimize RV function


    Anesthetic goals in ms and mr
    Anesthetic Goals in MS and MR mitral valve during systolic phase


    Technique of anesthesia in mr
    Technique of anesthesia In MR mitral valve during systolic phase

    Regional vs General Anesthesia in MR

    • Peripheral nerve blocks

      • Safe

      • Avoid intravascular drug injections (ultrasound/nerve stimulator guided blocks)

    • Central neuraxial blocks

      • Preload: ↓ HR: ↔/ ↑/ ↓, Contractility: ↔

        Afterload: ↓ Pulmonary vasculature: ↔

      • Mild/ Moderate MR (NYHA class I & II): SAB and epidural are well tolerated (avoid bradycardia)

      • Severe MR (NYHA class III & IV): Prefer GA over SAB and epidural


    Monitoring1

    Asymptomatic mitral valve during systolic phase

    Standard non-invasive

    ECG,

    HR

    NIBP

    Pulse-oxymeter

    Capnograph

    Temperature

    Symptomatic pts or major surgery

    Standard non-invasive

    Serial ABG

    Invasive monitoring

    IBP

    CVP/PAC

    Echocardiography (TTE/TEE)

    Cardiac catheterization

    Monitoring


    Management of ga
    Management of GA mitral valve during systolic phase


    Non-opioid induction agents mitral valve during systolic phase


    Muscle relaxants1
    Muscle Relaxants mitral valve during systolic phase


    Maintenance
    Maintenance mitral valve during systolic phase

    Narcotic oxygen relaxant technique

    Use of N2O – declined


    Summary of mr
    Summary of MR mitral valve during systolic phase

    • 90% of Rheumatic MR are associated with MS

    • LV has to deal with large volume- only a fraction goes to systemic circulation

    • Patient may present with CHF, pulmonary edema & LV dysfunction

    • Patients may be on diuretics, digitalis & anticoagulants- to be managed as per patients condition and guidelines.

    • Bradycardia has to be avoided at any cost

    • Systemic vascular resistance (afterload) should be kept slightly low

    • Preload should me maintained

    • NYHA I & II :- neuraxial block or GA

    • NYHA III & IV :- GA preferred over neuraxial block


    Summary
    Summary mitral valve during systolic phase

    • Valvular heart disease poses challenge during anesthesia

    • We should know pathophysiology of each valvular heart diseases

    • Most of the time, valvular heart diseases occur in combination

    • Our aim is to maintain normal cardiac output & tissue perfusion by regulating heart rate/rhythm, preload, afterload, myocardial contractility.

    • Use of regional anesthesia is not contraindicated in theses patients, but proper patients selection & precaution are must.


    References
    References mitral valve during systolic phase

    • Kaplan’s Cardiac Anesthesia; 5th edition

    • Miller’s Anesthesia; 7th edition

    • Clinical Anesthesia; Barash, Cullen, Stoelting, 5th edition

    • Stoelting’s Anesthesia & Co-existing Disease; 5th edition

    • Harrison’s Internal Medicine; 17th edition

    • Wylie & Churchill- Davidson’s A Practice of Anesthesia; 7th edition

    • Clinical Anesthesia; Morgan 4th edition


    Thank you
    Thank you mitral valve during systolic phase


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