1. Catheter estimation of stenotic valves
Dr. DAYASAGAR RAO
KIMS
HYDERABAD

2. Stenotic valve orifice area-evaluation
Cardiac catheterization- gold standard?
Echo doppler
MRI based Clinical
MDCT

3. Stenotic valve orifice area-evaluation
Is there role of catheter based assessment- stenotic valves in 2009?

4. ACC/AHA guidelines valvular heart disease-evaluation 2008
Discrepancy: clinical findings
noninvasive data .
Technically unsatisfactory non invasive data (echo-doppler)
operator dependent
acoustic window
TEE
Low flow- low gradient: aortic stenosis

5. Catheter based – evaluation of stenotic orifice
Is it safe?
tight/ critical stenosis
cerebral embolism- calcific aortic stenosis
Omran et al: LANCET 2003
152 patients aortic stenosis
randomized: CAG only Vs
CAG + crossing of aortic valve (retrograde)

6. Stenotic orifice area (catheter based)
Brain MRI: diffusion imaging
22% focal diffusion imaging abnormalities
3% clinically apparent neurodeficit
only in patients- crossing of aortic valve.

7. Stenotic orifice area- catheter based
Aortic stenosis: retrograde approach
antegrade
Mitral stenosis: LV- PCW
LV- LA

8. Stenotic orifice area AORTIC STENOSIS- (LV-AO)
METHOD
EASE OF USE
DISADVANTAGE
PULLBACK
+++++
LEAST ACCURATE
FEMORAL SHEATH
PRESSURE AMPLIFICATION ILIAC ARTERY STENOSIS
DOUBLE ARTERIAL PUNCTURE
+++
EXTRA VASCULAR ACCESS RISK
PIG TAIL- DOUBLE LUMEN
DAMPING
PIG TAIL + PRESSURE
EXPENSE
TRANSEPTAL ++
RISK

9. STENOTIC ORIFICE AREA MITRAL STENOSIS LV-PCW LV-LA TRANSEPTAL
PROPER PCW PRESSURE: MEAN WEDGE- MEAN PA
ALIGNMENT MISMATCH- TIME DELAY msec
REALIGNMENT- PEAK OF V WAVE BISECTED BY LV PRESSURE DOWNSTROKE.

10. STENOTIC ORIFICE AREA MILD MODERATE SEVERE AORTIC >1.5 sq cm
MITRAL
TRICUSPID
PULMONARY
Peak gradient >60 mm hg

11. VALVULAR STENOSIS- SEVERITY
Valvular disease cause of symptoms
Timing of intervention: symptomatic status
natural history- symptoms

12. Stenotic orifice area Geometric orifice area Effective orifice area
Critical valve area

13. DIAGRAM SHOWING Geometric / effective orifice area
Contraction co efficient

14. Contraction coefficient

15. STENOTIC ORIFICE- VALVES
Hemodynamic impact influenced by
Cross sectional area
Geometry of valve – flat valves have greater contraction co-efficient (for similar CSA and volume flow)

16. Stenotic orifice area Clinical implication: - Planimetry area
Effective orifice area (continuity/Gorlins)
EOA smaller than planimetered area- proportional contraction coefficient.

17. PRESSURE RECOVERY Fluid energy= pressure energy+ kinetic energy
Narrowed orifice (vena contracta) highest velocity
Downstream - flow stream expands
Deccleration (decreased velocity- kinetic)
Conversion kinetic – pressure
(pressure recovery)

18. PRESSURE RECOVERY

19. Clinical implication- pressure recovery
Doppler derived gradients- using CW vena contracta
Catheter derived gradients- downstream vena contracta- pressure recovery
GRADIENT DERIVED BY CATH IS LOWER THAN DOPPLER DERIVED GRADIENT

20. PROSTHETIC VALVES Bileaflet valves
Side orifice velocities are less than central orifice velocities. (side orifice velocities is 85% of central orifice)
Pressure recovery occurs much further downstream in central orifice than side orifice.
Discrepancy measurement of gradients- over time.

21. Stenotic orifice area- pressure recovery
Pressure recovery is more across aortic than at mitral
prosthetic valve- native valve.
Pressure recovery- exaggerated in
Smaller aorta
Stiffer aorta
Hypertension
Discrepancy between catheter derived and doppler derived pressure data. (thus calculated valve area)

22. Stenotic orifice area- pressure recovery (exaggeration- HTN)

23. Stenotic valve area Torricelli’s law F= A X V A=F/V A=F/V Cc F- Flow
A- Valve area
V- Velocity of flow
Cc- coefficient of contraction

24. Stenotic valve area V2 = (CV)2 X 2Gh V= (CV) x sq root 2Gh
h = pressure gradient
G = gravitational constant (980 cm/sec2)
for conversion cmH2 to units pressure
Cv- coefficient velocity for correcting energy loss
(pressure energy- kinetic energy)

25. Stenotic valve area A= F/V F- flow (vol flow ml/sec)
Flow rate= cardiac output/ duration of systole or diastole (SEP/DFP X HR)

26. Stenotic valve area Valve area= cardiac output ÷ (HR X SEP)
44.3 X C X sq root of pressure gradient
C- empirical constant
calculated valve area (by Gorlin)
actual valve area (at surgery)
Mitral Valve = constant 0.7 (later changed 0.85)
Aortic valve: assumed to be 1

27. GORLINS FORMULA (AHJ 1951 Gorlin R, Gorlin G) Eleven patients
Right heart catheterization- PCWP
Assumed LV diastolic pressure- 5mmhg
Duration diastole- peripheral arterial tracing
Calculated mitral valve area
Measured MVA at surgery

28. GORLIN FORMULA Cardiac output
Pressure gradient across valve (mitral/aortic)
Duration of flow (DFP/SEP)- pressure tracing
Constant (calculated-measured valve area)

29. GORLIN FORMULA Empirical constant includes
Conversion of cms H2o to units of pressure
Contraction co-efficient
Velocity co-efficient
Difference-
valve area calculated-
and valve area at surgery

30. GORLIN FORMULA Problems cardiac output Fick - oxygen consumption
Thermodilution- low output state
- significant TR
Duration of flow (SEP-DFP)
Alignment mismatch
Calibration errors

31. GORLIN FORMULA Modification: HAKKI cardiac output (L/ min)
Sq root of MPG
Heart rate: / min

32. Stenotic valve orifie area
Catheterization : gold standard ? (Grossman et al 2006)
Invasive procedure
Risk
Limitations – measured parameters
- calibration
-valvular regurgitation
Expensive
ACC/AHA Guidelines