1. Slides courtesy of Dr. Randall Harada
Aortic Stenosis
Slides courtesy of Dr. Randall Harada
2008
Zoll Firm Lecture Series

2. Zoll Firm Lecture Series
Etiology
Age < 70
Age ≥ 70
2008
Zoll Firm Lecture Series

3. Zoll Firm Lecture Series
Pathophysiology
Aortic stenosis
Increased afterload
Atrial contraction
LVH
Increased preload
Preserved wall stress
Normal systolic function
2008
Zoll Firm Lecture Series

4. Zoll Firm Lecture Series
Pathophysiology
Aortic stenosis
Increased afterload
LVH
LVH inadequate
(afterload mismatch)
↑ O2 demand
↓ coronary perfusion pressure
Compression of intramyocardial arteries
↓ CBF per unit of mass
Reduced myocardial contractility
Myocardial ischemia
2008
Zoll Firm Lecture Series

5. Zoll Firm Lecture Series
Natural history
Mortality is low during the latent period; similar to age-matched controls. The risk of surgery outweigh the benefit in this population.
Progression to symptomatic or severe aortic stenosis has marked individual variability
Average rate of progression 0.10 – 0.12 cm2 per year.
2008
Zoll Firm Lecture Series

6. Natural history Severe stenosis with symptoms: Avg life expectancy (y)
Angina 5
Syncope 3
Heart failure
<2
Ross J, Circ 36(supp IV) 1968
2008
Zoll Firm Lecture Series

7. Zoll Firm Lecture Series
Clinical care of AS
Assessment of symptoms; patient education
Careful exercise testing for asymptomatic patients with unclear medical histories:
Echocardiography: eval AS severity, LV function
ACC/AHA, Circ 114, 2006
2008
Zoll Firm Lecture Series

8. Zoll Firm Lecture Series
AS severity
Maximum aortic velocity
Mild: – 3.0 m/s
Moderate: 3 – 4 m/s
Severe: >4 m/s
Mean transvalvular gradient
Mild <25mmHg
Moderate mmHg
Severe >40mmHg
Aortic valve area by continuity equation
Mild: > 1.2 cm2
Moderate: 0.8 – 1.2 cm2
Severe: < 0.8 cm2
2008
Zoll Firm Lecture Series

9. Zoll Firm Lecture Series
Medical therapy
No medical therapies proven to prevent or delay AS
In severe AS, atrial fibrillation is often poorly tolerated
2008
Zoll Firm Lecture Series

10. Timing of valve replacement
2008
Zoll Firm Lecture Series
Otto CM, JACC 47, 2006

11. Timing of valve replacement
Otto CM, JACC 47, 2006
2008
Zoll Firm Lecture Series

12. Problematic situations
LV dysfunction
Primary cardiomyopathy vs. secondary due to true AS
Low stroke volume may reduce leaflet motion in a non-stenotic valve
Dobutamine stress echo to differentiate
Flexible leaflets: increase in EF, leaflet excursion, and AVA
Severe AS: increase in EF, no change in AVA
“Lack of contractile reserve”: no increase in EF
2008
Zoll Firm Lecture Series

13. Zoll Firm Lecture Series
Aortic valvuloplasty
Not an effective long-term therapy for most adult patients. Nearly 50% of the patients have re-stenosis in 6 months.
Mainly used for “palliation” and as a bridge to AVR and sometimes for patients who requires urgent non-cardiac surgery.
Serious complications (stroke, severe aortic regurgitation, myocardial infarction) occur in approximately 10 to 20 percent of patients
2008
Zoll Firm Lecture Series