11. AR

Question 0

Acute Aortic Regurgitation

Answer 0

• least well tolerated acute lesion

- leads to pulmonary congestion

Question 1

Chronic Aortic regurgitation causes increase in preload and afterload

Answer 1

Preload:

• additional end diastolic volume from valve regurgitation
• ventricle responds by dilating to accommodate
• eccentric hypertrophy

Afterload:

• increased radius of ventricle increases wall stress
  
  • LaPlace wall stress = radius x pressure / wall thickness
• concentric hypertrophy as evidence by normal wall thickness despite dilation of ventricle

Question 2

AR Assessment, Jet height/LVOT diameter

Answer 2

• ME LAX view
• jet height immediately below (within 1cm) AV plane
• maximal height during diastole selected

Mild: 25-45%
Mod: 46-65%
Severe: >65%

Question 3

AR Assessment, Jet area/LVOT area

Answer 3

• ME AV SAX view
• probe advanced immediately below valve plane
• more accurate than jet height/LVOT diameter, but more difficult

Mild: 4-25%
Mod: 26-60%
Sever: >60%

Question 4

Limitations to Color Flow Evaluation of AR

Answer 4

• can be deceiving if AR is thin jet between two cusps that coincidentally lines up in ME LAX
• eccentric jets are not well assessed with this method (must use PISA)

Question 5

AR Assessment, Vena Contracta

Answer 5

• narrowest part of the jet crossing the valve plane
• largest diameter during any portion of diastole is measured
• ** LOAD INDEPENDENT **

Mild: 6 mm

Question 6

AR Assessment, Aortic Diastolic Flow Reversal

Answer 6

• retrograde flow in either ascending or descending aorta during diastole
• best measured at the level of the arch
  
  • due to significant obliquity of aorta in this view, true velocities cannot be measured -> only comparison of ratio of the two important anyways
• normally a minor retrograde flow pattern in ascending aorta

Severe: hold diastolic flow reversal in descending aorta

Question 7

AR Assessment, PHT & slope of jet decay

Answer 7

PHT

• time between when transvalvular AR pressure gradient is maximal and the time when the pressure gradient is half max
• derived from slope of jet decay
• elevated diastolic filling pressures of LV (HF, restrictive defect, diastolic dysfunction) cause more rapid equilibration between LV and root and overestimate severity of AR

Mild: >500
Mod: 200-500
Severe: <200

Question 8

AR Assessment, Depth of regurgitant jet

Answer 8

• no longer used clinically

Question 9

Velocity of LVOT concerning for LVOT stenosis

Answer 9

> 1.5 m/s

Question 10

Causes of AR

Answer 10

• sclerodegeneration
• rheumatic disease
• endocarditis
• abnormally cusp valve