Valvular Heart Disease: The Aortic Valve

1. Valvular Heart Disease: The Aortic Valve

2. Case • A 60 year old Asian female with a history of a heart murmur presents for a routine visit. She has no complaints. • Vitals are normal. A 4/6 mid systolic murmur is noted at the left upper sternal border. • An EKG shows no abnormalities.

3. Case • What is the next best step? • Do nothing, this murmur is benign • Do an exercise stress test to try to elicit symptoms of aortic stenosis. • Do nothing, the patient has had this murmur for a long time • Check an echocardiogram • Refer the patient to a cardiologist for further evaluation

4. Case I: Echocardiogram

5. Case • What is the next best step • Do nothing because aortic stenosis is not severe • Start a beta blocker and ACE-I for optimal blood pressure control • Refer the patient to a cardiac surgeon for repair • Refer the patient to a cardiologist for further evaluation

6. What Makes A Heart Murmur? • High blood flow through a normal or abnormal orifice • Forward flow through a narrowed or irregular orifice • Backward flow through an incompetent valve

7. These Murmurs Are Benign • Mid systolic murmur at the left sternal border with grade 2 or less with a normal S1 and S2 and no other abnormal findings in an otherwise asymptomatic patient • Associated with normal or increased blood flow across normal valves

8. These Murmurs Need Further Evaluation • Diastolic Murmurs • Continuous Murmurs • Systolic • Loud • Early systolic • Late systolic • Holosystolic

9. Strategy For The Evaluation Of Cardiac Murmurs Bonow. JACC. 2006.

10. When To Order An Echo • Class I • Diastolic, continuous, holosystolic, late systolic, clicks, radiation to neck or back • Symptoms of underlying cardio-pulmonary disease • Grade 3 or louder mid systolic murmurs • Class III • Mid systolic mumur grade II or less thought to be innocent

11. Aortic Valve Stenosis • Obstruction of LV outflow • Common causes • Bicuspid • Degenerative calcific • Rheumatic • Rare causes • Congenital • Severe aortic atherosclerosis • Rheumatoid • Alkaptonuria Flather. Lancet, 2000.

12. Aortic Valve Characteristics • Normal Aortic Valve • Valve area 3-4 cm2 • Valve stenosis • 25% of normal valve area • Hemodynamic Progression • 0.12 cm2/year • 0.32 m/s increase in jet velocity/year • 7 mmHg increase in mean gradient/year

13. Epidemiology • Most common disease in western world • 50,000 valve replacements annualy • Age 65: 2% of patients • Age >80: >4% • 1 billion dollars annually in US

14. Etiologies of Aortic Stenosis Baumgartner. JASE, 2009.

15. Etiologies of Aortic Valve Disease Libby. Braunwald’s Heart Disease. 8th Ed.

16. Bicuspid Valve • 1-2% of births • Generalized arteriopathy: fragmentation of fibers of the elastic media • Coarctation, aortic dilation, dissection (5-9x risk) • Most common reason for valve replacement <70 years old • Roughly 66% of replaced valves < 70 • More common in men: 70-80% of cases • Hemodynamic abnormalities predispose to earlier stenosis Roberts. Circulation, 2005.

17. Bicuspid Aortic Valve

18. Calcific AS • Most common cause of AS • Present in 2% of adults 65 or older • Becomes symptomatic age 60-80 • Sclerosis present in 29% ≥ 65 • Proliferative and inflammatory changes-> calcification and bone formation • Risk Factors: HL, tob, HTN, DM

19. Rheumatic AS • Adhesions and fusion of commisures and cusps • Vascularization of leaflets-> retraction and stiffening of the free borders of the cusps • Calcific nodules • Small triangular orifice • Coexists with rheumatic mitral valve disease

20. Time Between Rheumatic Fever and Symptoms of Stenosis

21. Development of AS Otto. NEJM. 2008.

22. Pathophysiology of AS • Progressive obstruction and compensatory change • Pressure overload->increased wall stress->increased wall thickness • Increased myocardial collagen • Progressive systolic dysfunction • Progressive diastolic dysfunction • Decreased coronary blood flow

23. Pathophysiology Libby. Braunwald’s Heart Disease. 8th Ed.

24. Law of Laplace Yousef. BMJ. 1999.

25. Pathologic LV Hypertrophy Sorajja. Contemporary Cardiology, 2009.

26. Clinical Course • Outcome similar to normal in asymptomatic patients • Progression from sclerosis to severe AS: 2.5% in 8 years • Mortality is high in patients with symptomatic disease Cosmi. Arch Int Med. 2002.

27. Progression of Asymptomatic AS Otto. Circulation. 1997.

28. Mortality In Symptomatic Aortic Stenosis Is High Levy. NEJM, 2002. Ross J Jr, Braunwald E: Aortic stenosis. Circulation 38:V61, 1968

29. Survival With Or Without Valve Replacement Carabello. NEJM, 2002. Schwarz. Circulation, 1982.

30. Clinical Presentation • Age • Bicuspid: 50-70 years old • Calcific: > 70 years old • Symptoms • Progressive exercise intolerance • Angina (2/3 with significant CAD) • Syncope • Endocarditis, systemic embolization

31. Physical Examination Carotid upstroke Parvus and tardus: slow rising, late peaking Specific but insensitive Systolic murmur Late peaking heard at the base Varies beat to beat Louder with increased flow: squatting Quieter with decreased flow: standing Stops before A2 Can radiate to the apex (Gallivardin phenomenon) Second heart sound Absent A2 with severe disease Signs of heart failure Libby. Braunwald’s Cardiology. 8th Ed.

32. Aortic Stenosis Carotid Pulse Waveforms Libby. Braunwald’s Heart Disease. 8th Ed.

33. Dynamic Auscultation Libby. Braunwald’s Heart Disease. 8th Ed.

34. EKG and CXR • EKG • LVH • Atrial enlargement • Conduction abnormalities • Chest XR • Rounding of LV border and apex

35. Further Assessment • Unclear symptoms • Treadmill exercise testing • Development of symptoms • Failure to increase BP > 10 mmHg • NOT IN SYMPTOMATIC PATIENTS • Low left ventricular function • Dobutamine infusion

36. Low Cardiac Output: Response to Dobutamine Infusion Increase in CO. No change in grad. No change in CO, dec grad and hypotension. Increase in CO and grad. No change in AVA. Sorajja. Contemporary Cardiology, 2009.

37. Echocardiogram in AS • Valve anatomy definition • LV hpertrophy and systolic function • Transaortic velocities and gradients

38. Echo Assessment of Aortic Stenosis Baumgartner. JASE, 2009.

39. Severity of Aortic Stenosis Baumgartner. JASE, 2009.

40. Medical Therapy For Aortic Stenosis

41. Bonow. JACC, 2006.

42. Non-Operative Management of Aortic Stenosis • Counseling to monitor for symptoms • Evaluate and treat CAD • Reassessment • For symptoms changes • Severe: Annually • Moderate: 1-2 years • Mild 3-5 years • Balloon valvulotomy

43. When To Refer To Cardiology • All symptomatic • AS with LV dysfunction • Asymptomatic progressive disease • Atypical presentations

44. Operative Management Of AS • Class I • Symptomatic • Severe AS undergoing cardiac surgery • Severe AS and EF < 50% • Class II • Moderate AS undergoing cardiac surgery • Asymptomatic with severe AS and abnormal ex response • Asymptomatic severe with risk of rapid progression • Mild AS undergoing cardiac sx, concern for rapid progression • Very severe asymptomatic with low op mortality

45. Surgical Mortality • 3-4% for AVR alone • 5.5-6.8% with AVR plus CABG • 33% increased mortality in low volume centers

46. Surgical Risk Calculator euroscore.org/ www.sts.org/sections/stsnationaldatabase/riskcalculator/

47. Transcatheter Aortic Valve Replacement May Be An Option For High Risk Patients http://www.edwards.com/eu/products/transcathetervalves/sapienthv.htm

48. Transcatheter Aortic Valve Replacement For High Risk Patients Leon. NEJM, 2010.

49. Leaflets (46%) Degenerative (75% with some AR) Endocarditis Trauma Congenital Rhematic Myxomatous Systemic disorders: SLE, giant cell and Takayasu’s, ankylosing spondylitis, Whipple’s, Chron’s, weight loss drugs Aorta (54%) Age Degenerative disease (Marfan) Dissection HTN Syphilis Ankylosing spondylitis Giant cell arteritis Behcet syndrome Psoriatic arthritis Osteogenesis imperfecta Reieter syndrome Relapsing poychondritis Aortic Regurgitation Rigolin. Contemporary Cardiology, 2009. Roberts. Circulation, 2006.

50. Pathophysiology • LF ejection split between forward and back • Total stroke volume is increased • Left ventricle dilates to accommodate stroke volume • Increased LVEDP and hypertension -> increased preload and afterload -> eccentric hypertrophy • Mismatch-> systolic dysfunction -> fibrosis-> dysfunction becomes permanent