1. Cardiac Valves
Jeffrey R. Scott, Ph.D.

2. Heart – The primary pump

3. Anatomy / Function – Heart Facts
The Average Heart:
Weighs ~7-15 ounces (200 – 425 grams)
Is slightly larger than the size of a persons fist.
Beats ~100,000 times each day.
Pumps ~2,000 gallons (7,571 liters) of blood each day.
Will beat ~3.5 billion times in a lifetime.

4. Anatomy - Heart

5. Anatomy – Chambers 4 Chambers Right Atrium Right Ventricle Left Atrium
Left Ventricle
(largest and strongest)

6. Definition Cardiac Valve
One of the four structures within the heart that prevent backflow of blood by opening and closing with each heartbeat. They include the tricuspid, pulmonary, mitral (or bicuspid), and the aortic valve.

7. Anatomy – Valves 4 Valves
Tricuspid Valve: Between Right Atrium and Right Ventricle
Pulmonary Valve: Between Right Ventricle and Pulmonary Artery
Mitral Valve: Between Left Atrium and Left Ventricle
Aortic Valve: Between Left Ventricle and Aorta

8. Anatomy – Heart Valves
The primary function of Cardiac Valves is to ensure unidirectional blood flow.

9. Anatomy – Heart Valves

10. Anatomy – Heart Valves Number of Leaflets Tricuspid Valve: 3
Pulmonary Valve: 3
Mitral Valve: 2
Aortic Valve: 3
During Systole
(Ventricle Contraction)

11. Heart – Pattern of Blood Flow - Video

12. 2. Valvular Insufficiency / Regurgitation
What Problems Can Occur?
1. Valvular Stenosis
- stiff or fused leaflets which cause narrowing of the valve opening.
2. Valvular Insufficiency / Regurgitation
- inappropriate valve seal or closure causing leakage.

13. Cardiac Valve Disease - Scope of the Problem
~5 million people in the U.S. are diagnosed with cardiac valve disease per year.
Types: 1. Congenital (Present at Birth)
2. Acquired Over Time (Most Common)
3. Result of an Infection (i.e. Rheumatic Fever)
Note:
Rheumatic fever (RF) is an illness which arises as a complication of untreated or inadequately treated strep throat infection, which can seriously damage the valves of the heart. Throat infection with a member of the Group A streptococcus (strep) bacteria is a common problem among school-aged children. It is easily treated with a ten-day course of antibiotics by mouth. However, when such a throat infection occurs without symptoms, or when a course of medication is not taken for the full ten days, there is a 3% chance of that person developing rheumatic fever.

14. Regurgitation disease
Cardiac Valve Disease - Types
Valve Involved
Stenotic disease
Insufficiency/
Regurgitation disease
Aortic valve
Aortic valve stenosis
Aortic insufficiency/regurgitation
Mitral valve
Mitral valve stenosis
Mitral insufficiency/regurgitation
Tricuspid valve
Tricuspid valve stenosis
Tricuspid insufficiency/regurgitation
Pulmonary valve
Pulmonary valve stenosis
Pulmonary insufficiency/regurgitation
Both Tricuspid and Pulmonary Valve Disease are less common than Aortic and Mitral Valve Disease due to lower pressures on the right side of the heart.

15. Diagnosis - Echocardiogram
An echocardiogram is a diagnostic test which uses ultrasound waves to capture images of the heart chambers, valves and surrounding structures. It can measure cardiac output, is a sensitive test for inflammation around the heart (pericarditis), and can be used to detect abnormal anatomy or infections of the heart valves.

16. Valve Disease - Video

17. Etiology of Disease Aortic Stenosis
Calcification of tricuspid aortic valve with age (>50%)
Calcification of bicuspid aortic valve (30-40%)
Rheumatic fever (<10%)
Risk Factors that may accelerate disease:
Hypertension
Diabetes mellitus
Hyperlipoproteinemia (High Lipids)
Uremia (High Nitrogen)
Result:
Causes increased pressure in the left ventricle and impaired flow through the aorta.

18. Aortic Valve Stenosis – Examples
Normal
Congenital (Bicuspid) Stenosis
Rheumatic Stenosis
Calcified Stenosis

19. Etiology of Disease Aortic Regurgitation Acute Infective Endocarditis
Trauma
Chronic
Primary valvular disease caused by:
Rheumatic fever, bicuspid aortic valve, Marfan's syndrome, Ehlers–Danlos syndrome, ankylosing spondylitis, systemic lupus erythematosus.
Result:
Causes backflow of blood into the left ventricle during diastole.

20. Aortic Valve Stenosis / Insufficiency

21. Aortic Valve Stenosis / Insufficiency
- Symptoms

22. Aortic Valve – Repair Options

23. Etiology of Disease Mitral Stenosis
Primary cause is Rheumatic Heart Disease
Risk Factors that may accelerate disease:
Pregnancy
Result:
Causes increased pressure in the left atrium and the pulmonary circulation. Congestion may cause thromboembolism, and atrial hypertension may cause atrial fibrillation.

24. Etiology of Disease Mitral Regurgitation Acute
Endocarditis - primarily due to S. aureus.
Papillary muscle rupture or dysfunction, including mitral
valve prolapse
Chronic
Rheumatic fever
Marfan's syndrome
Cardiomyopathy
Result:
Causes backflow of blood into the left atrium during systole.

25. Mitral Valve Insufficiency - Symptoms

26. Mitral Valve – Repair Options

27. Open Cardiac Valve Replacement

28. Open Cardiac Valve Replacement

29. Open Cardiac Valve Replacement

30. Open Cardiac Valve Replacement

31. Percutaneous Valve Replacement

32. Valve Replacement
Mechanical / Tissue Valves

33. Reasons for getting a Mechanical Valve
Child or adolescent
Needs a valve to last a lifetime
Experiences highest rate of failure for tissue valves
Adults up to age 60
Need a valve to last 20–30 years and beyond
Experience a higher rate of failure for tissue valves than older adults
People are already taking blood-thinning medication(s)
No advantage in tissue valve

34. Mechanical Valves - Types
Starr-Edward’s Caged Ball Valve
Ball valves
Starr-Edward’s valve
Only ball valve implanted in US
Disk valves
Single leaflet
Bjork-Shiley valve
No longer sold in US
Medtronic-Hall valve
Omniscience valve
Bileaflet
St. Jude valve
90% of market
Carbomedics valve
Edwards-Duromedics valve
No longer available in US
St. Jude Medical Bi-leaflet Valve
Medtronic-Hall Single
Leaflet

35. Edwards (9 Commandments) of Cardiac Valves
1. Embolism Prevention.
2. Durability and corrosion resistance had been improved by forming the struts from stainless steel instead of Lucite.
3. Ease and Security of Attachment. Ease and security of attachment had been improved by changing the shape of the sewing ring from that of a doughnut to a flange; the new shape allowed greater contact with the annulus.
4. Preservation of Surrounding Tissue Function. Preservation of surrounding tissue function had been improved via 2 modifications: the profile of the cage was made rounder where it had previously been conical, and a porous silicone-rubber sponge was inserted into the body of the sewing ring to provide flexibility and an antibiotic reservoir.
5. Reduction of Turbulence. Turbulence had been reduced by increasing the orifice-to-ball ratio.
6. Reduction of Blood Trauma. The mesh size of the Teflon fabric was enlarged to encourage neointima formation and to reduce blood trauma.

36. Edwards (9 Commandments) of Cardiac Valves
7. Reduction of Noise. Hufnagel's early valves had a nylon poppet that made a distinct clicking noise that was audible to the patient and to people around the patient. Hufnagel later covered the poppet with silicone to reduce the noise. The poppet of the Starr-Edwards valve was made of a solid piece of compressed silicone. The Starr-Edwards valve was quieter than Hufnagel's valve, but it could still be heard in thin-chested people if the observer placed his or her ear a few inches away from the patient's naked chest.
8. Use of Materials Compatible with Blood and Tissue. All of the materials used by Starr and Edwards had been shown to be nonreactive with blood and tissue. These materials included Stellite 21 (a mix of cobalt, chromium, molybdenum, and nickel), Teflon cloth, Teflon suture, methyl methacrylate, stainless steel type 302, and compression-molded silicone rubber.
9. Development of Methods of Storage and Sterilization. For sterilization, the valve was cleaned with detergent and autoclaved before it was implanted in the patient. The valve could be stored and autoclaved again, if necessary.

37. Issues with Ball Valves
Primary issues
Ball larger than opening in valve to properly occlude valve when valve shut
Suboptimal Hemodynamics
Obstruction of blood flow by large ball
Attempts to decrease relative size of ball

38. Leaflet Valves Single leaflet Bjork-Shiley valve No longer sold in US
From the following article The artificial heart valve Albert Starr Nature Medicine 13, (2007) doi: /nm1644
Single leaflet
Bjork-Shiley valve
No longer sold in US
Medtronic-Hall valve
Omniscience valve
Bi-leaflet
St. Jude valve
90% of market
Carbomedics valve
Edwards-Duromedics valve
No longer available in US
(a) The first animal implant: a bi-leaflet valve with a Dacron single-layer sewing ring.
(b) A left atrial view of thrombotic occlusion two days after implantation in a dog.
(c) A modified bi-leaflet valve with enhanced sewing ring and rearranged leaflets.
(d) Thrombosis two days after implantation of the modified valve.

39. Bi-leaflet Valve – St. Jude
Cage - pyrolytic carbon
Sewing ring - velour polyester
Non-rotatable (sutured)
Rotatable
Valves - pyrolytic carbon

40. Advantages / Disadvantages
Mechanical Valves:
Advantages / Disadvantages
Advantages
High durability
Mechanical heart valves placed in young patients because they typically last for the lifetime of the patient
Disadvantages
Increased risk of blood clotting
Anti-coagulant drugs (sodium warfarin)
Suitable for people who do not want additional valve replacement surgery in the future

41. Tissue (Biologically-derived) Valves
Xenografts
Porcine
Bovine
Allografts

42. Tissue (Biologically-derived) Valves
Porcine
Hancock (Medtronic, Inc.)
Carpentier-Edwards (Baxter, Inc.)
Bovine Pericardial
Carpentier-Edwards
Stentless
St. Jude Toronto
Medtronic

43. Porcine Valves Hancock (Medtronic, Inc.)
Single porcine valve sewn (glut. processed) into polypropylene stent
Stent reinforced with Co-Cr-Ni alloy
Sewing ring-polyester with silicone insert

44. Bovine Pericardium Valves
Carpentier-Edwards
Baxter Healthcare, Edwards CVS Division
Durability-12 years
Stented valve
Similar to porcine valve except for tissue used

45. Bovine Pericardium Valves
Advantages:
Good hemocompatibilty
40% of US tissue valves
Most often used to replace aortic valve because of small size
Disadvantages:
Based upon experience with Ionescu-Shiley PC valve
6-8 year failure rate
Tearing of pericardial tissue from stent posts (high stress regions)
Addressed by CE valves resulting in increased wear rate of 12 years

46. Porcine (Stentless) Valves
St. Jude Toronto
Removal of entire aortic root and adjacent porcine aorta as a block
Coronary arteries tied off
Entire unit implanted
Dacron covering for ease of sewing/implantation
More blood flow through valve due to lack of stent?
Difficult to implant
Special measurements

47. Human-derived Valves Homografts Cadaveric graft
No immunosuppression required
Donated valves preserved in liquid nitrogen
Thawed directly before transplant
Sizing must be predetermined by MRI
Limited supply

48. Tissue Valves: Disadvantages
Calcification
Wear and tear
Infection
10-15 years

49. Cardiac Valves
Jeffrey R. Scott, Ph.D.