8. MR

Question 1

Mitral Valve Anatomy

Answer 1

• large anterior leaflet
  
  • 2/3 area of the valve
  • shares the same fibrous attachment as
    aortic valve = crux of heart or fibrous body
    
    • specifically left coronary cusp and half
      of non-coronary cusp attach to ring
• smaller posterior leaflet
  
  • 2/3 circumference of valve
  • contains three scallops
• both leaflets have identical overall surface area
• mitral annulus encircles mitral valve
  
  • fibromuscular ring
• two papillary muscles: anterolateral and posteromedial

Question 2

Types of chordae

Answer 2

1. Primary
   - attach to tips of leaflet
2. Secondary
   - attach to middle of leaflet
3. Tertiary
   - attach to base of leaflet

Question 3

Nomenclature of MV

Answer 3

Classic: anterolateral, middle, posteromedial
- anterolateral closest to LAA

Carpentier: P1, P2, P3
- P1 closest to LAA

Duran: P1, PM, P2

• P1 closest to LAA
• Based on attachment to papillary muscles

Question 4

Carpentier Mechanism of MR

Answer 4

1. Type 1: normal leaflet motion
   - secondary to dilatation of annulus
   - MR jet central
2. Type 2: excessive motion
   - jet directed away from diseased leaflet
   - billowing, prolapse, flail
   
   • billowing: part of leaflet extends above
     annulus during systole, but coapt point
     remains at annulus
   • prolapse: leaflet tip above annulus
   • flail: leaflet edge flowing freely 2/2 rupture
     chordae
3. Type 3: restricted motion
   - 3a: structural
   
   • likely rheumatic
   • valve affected in systole and diastole
     - 3b: functional
   • coaptation prevented by tethering from
     LV dilation
   • ie ischemia when from CAD

Question 5

Coando Effect

Answer 5

A jet of fluid traveling along the wall will get sucked against the wall and appear smaller than in reality

Question 6

PISA MR

Answer 6

• Blood approaching a regurgitant orifice accelerates along a series of concentric hemispheres
• At aliasing point, radius and velocity known

Question 7

EROA by PISA

Answer 7

EROA = (area x nyquist velocity)/MR velocity

area of hemisphere: 2pi r^2

Assumptions:

• orifice is round
• area equation assume true round hemispheres
  
  • true at radius 1-1.5cm
• eccentric jets must be corrected for angle

Question 8

Simplified PISA for EROA

Answer 8

• Assumes nyquist limit 40cm/s and MR jet gradient 100mmHg

EROA = (r^2)/2

Question 9

Functional MR

Answer 9

• Usually falls into 3b category, restricted leaflets 2/2 LV dilation
• Occasionally involved annular dilation as well
• Associated with worse overall prognosis
• Best time to assess is PREOP
  
  • GA decreases preload and typically decreases MR reading by 1 level