ANATOMY OF HEART VALVES AND PROSTHETIC VALVES.pptx

Anatomy of Heart valves and development in prosthetic heart valves

1. HEART VALVES BY – Dr. Praval Bhatnagar DNB Trainee- 2 nd year Under the guidance of – Dr.(Prof.) A.K. Srivastava Dr. Manoj Kumar

2. MITRAL VALVE The mitral orifice, smaller than the tricuspid orifice, is a well-defined transitional zone between the left atrial wall and the inserted margin of the mitral valvular leaflet bases. It measures, on average, 9.0 cm in circumference in males and 7.2 cm in females. The free edge of the mural and aortic leaflets normally bear several indentations that create a scalloped edge. Two indentations are sufficiently deep and regular to be defined as the ends of the solitary and oblique zone of apposition or the commissures of the valve.

3. The larger anterior (septal, aortic, anteromedial) leaflet is roughly triangular in shape, with the base of the triangle inserting on about one third of the anulus It has a relatively smooth free margin with few or no indentations. A distinct ridge separates the region of closure (rough zone) from the remaining leaflet (clear zone). The anterior leaflet is in fibrous continuity with the aortic valve through the aortic–mitral anulus and forms a boundary of the left ventricular outflow tract. The smaller posterior (mural, ventricular, posterolateral) leaflet inserts into about two thirds of the anulus and typically has a scalloped appearance

4. TRICUSPID VALVE The anterior (anterosuperior) leaflet is the largest of the three leaflets and may have notches creating subdivisions The posterior (inferior) leaflet is usually the smallest and is commonly scalloped. The septal leaflet is usually slightly larger than the posterior leaflet. Of major surgical importance is proximity of the conduction system to the septal leaflet and its anteroseptal commissure.

5. AORTIC VALVE The aortic valve comprises three semilunar cusps: the right coronary cusp, the left coronary cusp, and the non-coronary cusp. •⁠ ⁠ *Right Coronary Cusp:* Positioned anteriorly and gives rise to the right coronary artery. •⁠ ⁠*Left Coronary Cusp:* Located posteriorly and gives rise to the left coronary artery. •⁠ ⁠ *Non-Coronary Cusp:* Positioned opposite to the left coronary sinus and does not give rise to any coronary artery.

6. PULMONARY VALVE The pulmonary valve, guarding the outflow from the right ventricle, sits at the top of the conus arteriosus (infundibulum). It has three semilunar leaflets, attached by convex edges partly to the infundibular wall of the right ventricle and partly to the origin of the pulmonary trunk. Each leaflet is an endocardial fold with a variably developed intervening fibrous core that traverses both the free edge and the semilunar-shaped inserted margin.

7. PROSTHETIC HEART VALVE

8. TYPES OF HEART VALVES

9. MECHANICAL VALVES

10. History of Prosthetic Heart Valves First Mechanical valve was designed by Charles Hufnagel in 1954 ( Implanted in descending thoracic aorta for AR)

11. STAR EDWARDS VALVE Most widely used ball & cage valve for more than 40 years (1960-2007) Large patient population still with the valve Silicone rubber ball with 2% barium sulfate Cage- Stellite alloy Sewing ring-knitted Teflon & polypropylene cloth. Circular primary orifice Ring shaped secondary orifice between the ball and the housing Tertiary orifice: In the aortic position, between equator of the ball and aorta

12. ADVANTAGES Oldest Durability up to 40 yrs DISADVANTAGES No central orifice — only lateral orifice — very high transvalvular gradient Bulky design - not suitable if small LV cavity or aortic annulus. Excessive occluder -induced turbulence in the flow through and distal to the valve Thrombogenic risk is higher ie 4% to 6% per year  Hemolysis - Collisions with the occluder ball causes damage to blood cells

13. FLUROSCOPY

14. CAGE & DISC VALVE Introduced in mid-1960s for a better profile. Examples: Kay- Shiley , Beall Design similar to ball-and-cage valves - except that occluder disc instead of ball  Discontinued - inferior hemodynamic

15. TILTING DISC VALVES  Bjork- Shiley and Lillehei-Kaster tilting-disc valves in 1969 & 1970 respectively Over came the 2 major drawbacks of caged valves ; high profile & excessive turbulence DISC and a retaining STRUT mechanism Disc -totally occludes the valve orifice in the closed position & tilts to an angle in the open position. The disc can rotate in its axis - prevents excessive contact wear to particular region of the dis

16. TILTING DISC VALVE ADVANTAGES OVER BALL & CAGE Low profile Central blood flow. Decreased turbulence Reduced shear stress. Reduced Thrombotic risk DISADVANTAGES Thrombus and Pannus interfering with the motion of disc Sudden catastrophic valve thrombosis Careful orientation of disc needed during implantation

17. MEDTRONIC HALL VALVES Titanium housing, Teflon sewing ring, carbon coated disc. Single hole in the center of the disc. Goose-neck shaped central strut disk rides up and down on the strut. 2 second, smaller strut stops the motion of the disk when fully open. Opening angle: 75 degrees for aortic, 70 degrees for mitral. Approved in 1981, still use

18. BJORK & SHILEY 2 U shaped struts Larger inlet strut Smaller outlet strut deep into the disc well- retains The disc Radiolucent occluder disc with opaque marker Disk types : Flat & concavo - convex

19. TILTING DISC FLUOROSCOPY

20. TTK CHITRA VALVE Only Indian mechanical valve Research initiated in 1976 First Human implantation in 1990 Approved in 1995 4th generation in use now Ultra high molecular weight Polyethylene disc  Cobalt chromium alloy (Haynes-25) cage 3 struts,2 major, 1 minor strut. Machined from single block; no welds or joints. Minimum metal exposed to blood stream Opening angle 72 deg Polyester suture ring

21. FEATURES OF TTK-CHITRA VALVE Rotatable within the sewing ring - freedom of repositioning if needed. Silent operation Low profile Most price-friendly Low thromboembolism even if poor anticoagulant compliance

22. BILEAFLET VALVES First designed by St Jude Medical & introduced in 1978. FDA approved in 1982 Most widely used. Zingei -circular occluders called leaflets, which pivots about a recessed Open position - central rectangular orifice and two semi-circular lateral orifices. Closed position small gaps between the closed leaflets (b-datum gap) and between the leaflets and the housing (periphery gap) allow some degree regurgitation. Regurgitation also occur through the hinge region

23. BIOPROSTHETIC VALVES  Mechanical valves : life-long anticoagulation and the accompanying bleeding problems. Initial approach (1962) : antibiotic- or cryo-treated human aortic valves ( homografts ) Another approach (1967) was patient's own pulmonary valve used to replace the aortic valve (Ross procedure) followed by homografts for pulmonary position Later occassionaly performed on mitral valves also

24. Short comings : Durability especially for homografts  Availabilty of homografts Major breakthrough in 1969 Carpentier developed tissue fixation using glutaraldehyde Increased biological tissue stability and a decrease in biodegradation Inert but still biological tissue Concept of stent was also developed simulataneously New valve design, combining biological and mechanical structures to create a tissue-based valve with low thrombogenicity Term ' bioprosthesis ' by Carpentier

25. HETEROGRAFTS  Pericardium usually bovine in origin but may be porcine or equine Most of them mounted on a metallic stent Pericardial valves are almost invariably stented. 1st, 2nd or 3rd generation- According to the method of tissue fixation and treatments With 3rd gen valves offering improved freedom from structural degeneration

26. PORCINE VALVES

27. PERICARDIAL VALVES

28. STENT LESS VALVES

29. PERCUTANEOUS VALVE

30. PERCUTANEOUS AORTIC VALVES

31. PERCUTANEUOUS PULMONARY VALVES

32. TRICUSPID VALVE

33. THANK YOU