Mitral valve diseases

1. Pathophysiology of Mitral Valve Diseases
Dr. Dharmraj Singh
Senior Resident
Intensive Care (CTVS)

2. Outline
• Introduction
• Anatomy of Mitral Valve apparatus
• Acute Rheumatic Fever
• MS
• Chronic MR
• Acute MR
• Summary

3. Introduction
• Rheumatic fever is the leading cause of acquired heart disease in children
and young adults worldwide.
• Pharyngeal infection with group A beta-hemolytic streptococci (GAS) -
latent period of 2 to 3 weeks, the illness is characterized by acute
inflammation of the heart, joints, skin, subcutaneous tissue, and central
nervous system.
• The destructive effect on the heart valves leads to the chronic sequelae
of the disease → Rheumatic heart disease (RHD)→ with serious
hemodynamic disturbances causing cardiac failure, and other
complications such as stoke and infective endocarditis etc.

4. Curve A pre-antibiotic fall in the incidence of rheumatic fever industrialized countries
Curve B persistent high incidence of rheumatic fever in regions of the world with no comprehensive program for prevention
Africa and south Asia
Curve C post-antibiotic fall comprehensive programs for primary and secondary prevention of rheumatic fever
Curve D shows the fall and rise in the incidence of rheumatic fever in the formerly Soviet republics of central Asia.

5. Pathogenesis of Acute Rheumatic Fever
• Rheumatic fever is a multifactorial disease-
• Agent - GAS pharyngitis
• The host- susceptible individual
• Environment - under deprived social conditions
• Molecular mimicry - autoimmune response- cross-react with similar epitopes in the heart,
brain, joints and skin, and repeated episodes of rheumatic fever lead to RHD
• Antigen recognized as foreign by susceptible host and results in hyperactive immune
response (both humoral & cellular)
• Breakdown of immunogenic tolerance, and allows autoreactive immune-mediated injury

6. • Inflammatory process- damage to collagen fibrils and connective tissue ground
substance - fibrinoid degeneration ;
• Two-hit hypothesis
• Rheumatic fever is classified as a connective tissue or collagen vascular disease.
• Most frequently in children between ages 4 and 15 years
• In developing countries such as Saudi Arabia and India, juvenile mitral stenosis
may occur at age 3 to 5 years.
• The illness usually begins with a high fever (may be low grade or absent)
• Polyarthritis- 2/3 to 3/4 of patients
• Carditis
• Chorea

8. AHA-Revised Jones Criteria for Diagnosis of Rheumatic Fever*
Low-Risk Populations Moderate- and High-Risk Populations
MAJOR CRITERIA Carditis (clinical or subclinical†)
Arthritis (polyarthritis only)
Chorea
Erythema marginatum
Subcutaneous nodules
Carditis (clinical or subclinical)
Arthritis (including polyarthritis,
monoarthritis, or polyarthralgia‡)
Chorea
Erythema marginatum
Subcutaneous nodules
MINOR CRITERIA Polyarthralgia
Fever (≥38.5°C)
ESR ≥60 mm in the first hour and/or CRP
≥3.0 mg/dL
Prolonged PR interval, after accounting for age
variability (unless carditis is a major
criterion)
Monoarthralgia
Fever (≥38°C)
ESR ≥30 mm in the first hour and/or CRP
≥3.0 mg/dL§
Prolonged PR interval, after accounting for
age variability (unless carditis is a major
criterion)
*Annual acute rheumatic fever (ARF) incidence of ≤2 per 100,000 school-aged children or all-age rheumatic heart disease (RHD) prevalence of ≤1 per 1000 people per year.
†Defined as echocardiographic valvulitis
‡Polyarthralgia should only be considered as a major manifestation in moderate- and high-risk populations after exclusion of other causes.
§C-reactive protein (CRP) value must be greater than the normal laboratory upper limit. In addition, because the erythrocyte sedimentation rate (ESR) might evolve during the
course of ARF, peak ESR values should be used.

9. • Initial diagnosis of ARF - 2 major criteria or 1 major and 2 minor criteria
are present
• Diagnosis of recurrent ARF- 2 major, 1 major and 2 minor, or 3 minor
criteria in the presence of preceding GAS infection
Evidence of preceding GAS infection –
• Throat swab culture or
• Rising titre of antistreptococcal antibodies, either anti-streptolysin O (ASO) or anti-deoxyribonuclease
B (anti-DNase B) or
• Positive rapid group A streptococcal carbohydrate antigen
2015 AHA-Revised Jones Criteria for Diagnosis of Rheumatic
Fever

10. Investigations in Suspected Rheumatic Fever
Recommended for All Cases
WBC count
ESR or CRP
Throat swab before giving antibiotics for GAS culture
Blood culture, if febrile
Antistreptococcal serology: both antistreptolysin O (ASO) and anti-DNase
B titers (repeat after 10 to 14 days if first test is not confirmatory)
Electrocardiogram
Chest radiograph
Echocardiogram

11. Mitral stenosis

12. MITRAL STENOSIS
ETIOLOGY OF MITRAL STENOSIS
• Rheumatic fever
• Carcinoid Heart disease
• SLE
• Rheumatoid arthritis
• Extensive mitral annulus calcification
• Congenital MS

13. • Predominant cause of MS – RHD (Rheumatic changes- 99%)
• Isolated MS- 25%
• MS+MR – 40%
• Multivalve- 38%
• AV - 35%
• TV – 6%
• PV - rare
• Rheumatic MS - 2/3rd Female
• Interval b/w RF – MS about few years to > 20 years

14. Pathophysiological Triad
Etiology-the cause of the disease
Lesions-results from the disease
Dysfunction-results from the lesions

15. • Normal mitral valve area is 4 to 6 cm2
• Once the mitral valve orifice narrows to less than 2.5 cm2 a pressure
gradient is necessary to generate blood flow from the left atrium into the
left ventricle.
Based on a semi-quantitative grading system, mitral stenosis is typically
classified as
• Mild if the valve area is >1.5 cm2,
• Moderate when the valve area is between 1.0 and 1.5 cm2 ,
• Severe when the valve area is <1.0 cm2 or the mean transvalvular
pressure gradient exceeds 10 mm Hg

16. Pathogenesis of MS
• Non-Infectious delayed complication of streptococcal sore throat due
to Group A beta-haemolytic streptococcus
• ARF → Latency → MS
• Smouldering rheumatic valvulitis → abnormal flow across the mitral
valve → thickening, fibrosis and calcification of the cusps

17. Pathophysiology of MS
• Severity of MS – MVOA or degree of valve opening in diastole
• High LA pressure – maintain normal CO
• Transvalvular pressure gradient – square of the trans-valvular flow rate
• Increase in CO or tachycardia – increases flow rate - increases the
gradient

18. Pathophysiology

20. Hemodynamic Consequences of Mitral Stenosis
PULMONARY ARTERY HYPERTENSION
• Three components:
• Passive transmission of LA pressure
• Reactive pulmonary artery hypertension
• Potentially Fixed resistance – morphologic changes in the pulmonary vasculature
Protected MS – elevated pre-capillary resistance – pulmonary congestion symptoms
decrease – decreased CO

22. Left Atrium in MS
• LA Dilatation
• Fibrosis of atrial wall
• Disorganization atrial muscle bundles
• Substrate for Atrial Fibrillation → Disparate conduction velocities
and inhomogeneous refractory period
• Large LA → AF → Blood stasis → Clot

23. LV in MS
• 85% - LVed and Ejection indices are normal
• LV dysfunction – Late stages of Chronic Sev MS
• Regional Hypokinesis
• Myocarditis -> LV Stiffening
• Long standing MS - chronic reduction in preload and elevated afterload
• RV failure – V-V interdependence, septal shift and LV failure

24. Mitral Stenosis – Symptoms
• For a given stenosis C/F depends on
• Cardiac Output
• Pulmonary Venous Hypertension
• Pulmonary arterial hypertension
• In response to exertion
• Dyspnea
• PVH – increased PV pressure – fluid transudation from pulmonary capillaries – decreased
lung compliance – increased work of breathing
• Supine position increased PVH further – PND and orthopnea

25. Mitral Stenosis - Symptoms
• Hemoptysis
• Five causes by Woods
• Pulmonary apoplexy – PV and BV shunt
• Dyspnea with blood streaked sputum
• Bronchitis
• Pulmonary edema – pink frothy sputum
• PE and Infarct

26. Mitral Stenosis - Symptoms
• Hoarsenss of voice (Ortner syndrome)
• Compression of Lt RLN - large tense PA and aorta
• Thrombo-embolism
• LA clot/LAA clot
• Related to age and presence of AF
• Infective Endocarditis
• Isolated MS less common
• More common if associated MR/AR

27. MS - Late symptoms
• Secondary to PHTN, RV failure and Functional TR
• Easy fatigability
• Hepatic congestion
• Ascites
• Lower limb edema

28. PHYSICAL EXAMINATION
• Small volume peripheral pulse – ↓ CO
• JVP
• a - Raised atrial pressure
• a, v - Right heart failure
• cv - Severe TR
• Tapping apical impulse (palpable S1), RV type
• Palpable S2 - severe PHT
• Left parasternal lift - RVH

29. Physical examination
• S1 - pliable valve
• Opening snap pliable valve
• Mid-diastolic rumbling murmur
• Severity inflicted by murmur duration (rather than intensity)
• Short A2-OS (<60 ms) - favors severe MS
• Additional Determinants of A2-OS
• LA pressure
• Closing pressure of aortic valve (systemic HTN)

30. Roentgenographic findings
• Left atrial enlargement
• Redistribution of venous and arterial flow
to upper lobes
• Calcification of mitral valve
• Kerley B lines
• Enlarged pulmonary artery
• Enlarged right ventricle

31. Mitral regurgitation

32. Anatomy
• Mitral valve apparatus is composed of
mitral annulus, leaflets, chordae
tendineae, papillary muscles, and the left
ventricular lateral wall
• Chordae tendineae and papillary muscles
comprise the subvalvular apparatus.

33. Mitral regurgitation
Etiology of MR
• Mitral Annular Disorder
• Mitral Valve Leaflet Disorder
• Disease of the chordae
• Papillary Muscle Disorder
• Prosthetic valve disorder

34. Carpentier’s Functional Classification

35. Mechanism Functional Class
Rheumatic Retraction of thickened leaflets and chordae Type III
Degenerative Prolapsed leaflets Type II
Marfan’s Syndrome Ruptured chords and redundant tissue Type II
Ischemic Infarct (acute) Ruptured papillary muscle Type I
Ischemic (chronic) Reduced motion of leaflets, traction anterior
leaflet
Type IIIb
Endocarditis Destructive lesions, perforation, flail leaflets Type II
Congenital Cleft leaflet, transposed valve

36. Pathophysiology
• MR decreases impedence to LV – enhances LV emptying
• MR flow – instataneous Size of the orifice and LV-LA pressure gradient
• Torricelli principle –
• MRV = MROA x C x T x sq.root (LVP-LAP)
• LV-LA gradient – SVR
• MROA – Etiology of MR – variable response to drugs

38. STAGES OF MR
ACUTE MR
CHRONIC
COMPENSATED MR
CHRONIC
DECOMPENSATED
MR

39. MR AND LV COMPENSATION
ACUTE
FRANK-STARLING
PRINCIPLE
CHRONIC
LAW OF LAPLACE
MR begets more MR

40. Etiology of Acute non-ischemic MR
• Chordal rupture
• Infective endocarditis
• Myxomatosis valvular degeneration
• Trauma
• Hypovolemia in mitral valve prolapse

42. LV in acute MR
• Increase in Pre-Load (Frank Starling principle)
• Decrease in After Load
• Increase in Ejection Fraction
• Increase in Total Stroke Volume
• Diminished Forward Stroke Volume

43. Acute severe Vs Chronic severe MR
Acute Chronic
Symptoms Almost always present, usually severe May be present
Cardiac palpation Unremarkable Displaced dynamic apical impulse
S1 Soft Soft or normal
Murmur Early systolic to holosystolic Holosystolic
ECG Normal LVH and AF common
CXR Normal cardiac silhouette;
pulmonary edema
Enlarged heart, normal lung fields
ECHO Normal LA and LV Enlarged LA and LV

46. LV in Chronic MR

47. Ejection Indices in MR
• Ejection Fraction Indices
• Ejection Fraction (EF)
• Fractional Fibre Shortening (FS)
• Velocity of circumferential fibre shortening (VCF)
• Inversely related to After load

48. Ejection Indices in MR
• Elevated in early MR
• Chronic MR – diastolic overload – myocardial dysfunction
• Indices modestly affected
• Low to normal indices – impaired myocardial function
• LVEF - 40-45% (moderate dysfunction) - severe LV dysfunction

49. End Systolic Volume/Dimensions
• Independent of pre-load
• Varies linearly with afterload
• Reduced – Acute MR
• Normal – Compensated Chronic MR
• Increased – Decompensated Chronic MR
• Pre-op value >40mm – impaired lv function post op
• Index for evaluating LV function
• Predictor of function and survival following MV surgery

50. End Systolic wall stress
• Better index of after load
• Accounts for ventricular geometry
• High end systolic wall volume for given end systolic wall stress –
depressed contractility
• Predicts the prognosis for valve replacement

53. LA compliance
• Normal or Reduced Compliance
• In acute MR, marked increase in LA pressure
• LA thick walled
• Symptoms of pulmonary congestion

54. LA compliance
• Markedly Increased Compliance
• Thin walled, large LA
• Normal or slightly elevated LA pressure
• AF and low CO
• Moderately increased compliance
• Most common
• Variable sized LA/LA pressure -> AF

55. Symptoms of MR
• Mostly asymptomatic
• Chronic weakness & fatigue –most common
• Dyspnea/orthopnea/PND
• Palpitations
• Atypical chest pain
• Hemoptysis & systemic embolization- less common
• Acute MR -> Right sided heart failure
• Chronic MR -> Left sided heart failure

56. Physical examination
• Small volume brisk/jerky pulse – DEC FSV
• JVP
• a - Decreased RV compliance
• a, v - Right heart failure
• v - Severe TR/LAP In acute MR
• Hyperdynamic Apical impulse – LV Vol overload and dilatation
• Parasternal lift (dilated LA,RVH)
• Palpable S2 - severe PHTN

57. Physical Examination
• S1, Loud S1 in MVP (Ejection click)
• S2 –Wide split, loud P2, S3+
• Holosystolic murmur
• Severity inflicted by murmur intensity
• Radiates to axiila/back/base

58. Roentgenographic findings
• Cardiomegaly with LA and left atrial
appendages dilatation
• Giant left atria
• Annular calcification
• Interstitial edema with Kerley B lines

61. Thank you