1. Chapter 10 Calculation of Stenotic Valve Orifice Area
Presenter:李政翰
Supervisor:詹世鴻

2. Gorlin’s Formula 1st hydraulic formula
F=A*V*Cc ( F=flow rate, A=orifice area, V=velocity of flow, Cc=coefficient)
2nd hydraulic formula
V2 =(Cv2)*2gh ( h=PG in cm H2O, Cv=coefficient of velocity)
A=F/(C)*44.3*h½

3. Gorlin’s Formula A=F/(C)*44.3*h½ For MV or TV area calculation
F=CO/(DFP*HR), C=0.85
For AV or PV area calculation
F=CO/(SFP*HR), C=1

4. Mitral Valve Area
A=F/(C)*44.3*h½ h=x(F/A)2 F=CO/(HR)(DFP) h=x[CO/(HR)(DFP)A] 2

5. Example of Calculation of MS
CO=4680 cm3 /min, HR=80 beats/min
DFP=0.4 sec/beat MVA=0.71cm2

6. Pitfalls Pulmonary Capillary Wedge Tracing
Nishimura PG of MV was larger 3.3±3.5mm Hg when PAWP replaced LAP
Lange Direct measure (Transseptal) LAP, PAWP was larger only 1.7± 0.6 mmHg

7. Pitfalls The authors PAWP could substitute LAP except in:
a. pulmonary venoocclusive disease
b. cor triatriatum
c. failure to wedge properly
One should verify proper wedge
a. mean wedge pressure< mean PA
b. PaO2 ≥95% or at least equal to artery

8. Pitfalls Alignment Mismatch
There is a time delay in the transmission of LA pressure.
Realignment of a wedge tracing is practically more physiologic realignment

9. Pitfalls Calibration Errors Cardiac Output determination
CO should be measured simultaneously with the gradient determination
 MR and TR would make CO measurement inaccurate

10. Aortic Valve Area Critical Stenosis ~0.7cm2
Critical abrupt worsening of prognosis
PG=x[CO/(HR)(SFP)A] 2

11. Aortic Valve Area
Critical Valve stenosis may be determined by body size

12. Example The average PG: 40mmHg Systolic ejection period: 0.33 sec
HR: 74 bpm
Cardiac output: 5000 cm3/min
AV area=5000*74*0.33/(44.3*400.5)=0.7cm2

13. Is peripheral arterial pressure a satisfactory substitute for ascending aortic pressure when measuring aortic valve gradients?

14. Pressure tracings recorded from two catheters within the body of the LV
If catheter tip in LVOT, it may underestimate the true LV-aorta PG up to 30mmHg

15. PG recorded at different sites may vary widely
The differences in PG among different sites are up to 45mmHg

16. Another approach to increasing the accuracy of transaortic valve PG

17. Pitfalls Transducer calibration
Since in the absence of peripheral stenosis, mean pressure recorded by both catheters should be identical

18. Pitfalls Pullback Hemodynamics Carabello’s sign
Increase in peripheral systolic pressure of more than 5 mmHg when LV catheter pullback
This sign is present in more than 80% critical AS (AV area ≤0.5cm2)

19. Area of TV and PV Rare TV or PV stenosis in adults
In general, mean PG≥5mmHg across TV is sufficient to cause RV failure signs
PG≤50mmHg across PV are usually tolerated
PG≥100mmHg indicate surgical correction

20. Alternatives to the Gorlin Formula
Hakki (tested in 100 patients with AS or MS)
Valve area=CO(l/min)/PG1/2
Ex.1 (MS,0.71cm2): MVA=4.68/301/2=0.85cm2
Ex.2 (AS,0.73cm2 ): AV area=5/401/2=0.79cm2

21. Assessment of AS in patients with low cardiac output
Based on Gorlin Formula, Valve area depends on cardiac output.
Two mechanisms:
a. increase CO and LV pressure
physically opens the valve
b. incorrect empirical coefficient factor for AV

22. Assessment of AS in patients with low cardiac output
There are two conditions we should distinguish
a. intrinsic LV dysfunction combines with
mild AS
b. critical AS related LV dysfunction

23. Valve Resistence AV resistence= 1.33(mean PG)(SEP)(HR)/CO
 less flow-dependent, may be an important adjunct in patients with low CO

24. Recommendation of AS in patients with low cardiac output
For patients with CO≤4.5l/min, PG≤40mmHg, AV resistance≤275dyn-sec-cm-5
Recommend Nitroprusside or dobutamine infusion test
a. if PG increases probable severe AS
b. if PG decreases or slightly decreases and CO increases not severe AS, unlikely benefit from AVR

25. Chapter 29 Profiles in Valvular Heart Disease

26. Hemodynamic and Angiographic findings

27. Mitral Stenosis Normal orifice: about 4.5cm2
First, LA pressure rises and increase PG between LA and LV
Second, reduction of blood flow across MV
Third, pulmonary edema developed and reactive pulmonary arterial change
Two stenoses MV and Pul. arterioles

28. Catheterization Protocol
Indication: consider balloon mitral valvuloplasty or MVR
Procedure of right and left sided heart should be evaluated

29. Catheterization Protocol
Usual indication for MS balloon mitral valvuloplasty or corrective surgery
Both sided heart should be evaluated
A. Simultaneous PAWP and LV pressure
tracings for mitral orifice
B. if PG between MV < 5mmHg, error is
large. Induced tachycardia and increase
preload should be done for increasing PG

30. Catheterization Protocol
C. Measure PA, PAWP and cardiac output for calculating pulmonary vascular resistence.
D. RV and RA for RV function
E. Other valvular heart disease or congenital heart disease may co-exist

31. Mitral Regurgitation
Mitral valve apparatus leaflets, papillary muscles, chordae tendineae and annulus
Rheumatic heart disease, IE, MVP, AMI, LV dilatation

32. MR MR severity determined by: a. regurgitant orifice b. LA compliance
c. PG between LA and LV during systole
d. duration of systole
e. afterload of LV

33. Hemodynamic assessment
Both sided heart pressure evaluation
Interpretation of V wave in PAWP tracing:
Prominent V waves are insensitive and poor positive predictive for identifying mod or severe MR
ex. Left heart failure also had prominent V waves.
Giant V waves 3x PAWP or mean LA

34. Giant V wave

35. Exercise Hemodynamics
The patient usually fails to increase cardiac output appropriately with exercise (less than 80% of predicted)
PAWP or LA mean pressure commonly increase larger than 35mmHg by 4-5 minutes of supine bicycle exercise

36. Angiographic Assessment
LV angiography evaluate the severity of MR
Mild (1+) clear with each beat
Moderate (2+) does not clear with each beat and opacify entire LA after beats
Mod-severe (3+) complete opacify and equal opacification
Severe (4+) one beat opacify whole LA and stronger than LV and reflux to PV

37. Regurgitation Fraction
TSV (total LV stroke volume)
FSV (forward LV stroke volume)
RSV (regurgitant stroke volume)
RF (regurgilant fraction)
RF=RSV/TSV
Grade I <20%
Grade II %
Grade III %
Grade IV >60%

38. Catheterization Protocol
Right heart cath RA, RV, PA, PAWP (V waves height)
Left heart cath LVEDP
severe MR LVEDP<<LAP or PAWP
LV failure of CAD LVEDP~ LAP or PAWP
AR LVEDP>> LAP or PAWP
Measure cardiac output
LV angiography for MR and LVEF
Coronary angiography
Pharmacologic intervention nitroprusside would increase cardiac output

39. Aortic Stenosis Valvular, subvalvular and supravalvular
LV hypertrophy  AS related
Indications for cath
LV failure, angina, syncope

40. Hemodynamic assessment
Simultaneous measurement of pressure and flow across the AV

41. Carabello’s sign
LV catheter pullback in severe AS (AV area <= 0.6 cm2 ) would increase 5 mmHg in peripheral artery

42. Angiographic assessment
AS may result in high LVEDP intolerant to LV angiography
Aortography is usually not required except in condition when wide aortic pulse pressure
Selective coronary angiography is necessary especially if chest pain exists

43. Catheterization Protocol
Right heart cath for pressure and cardiac output
Left heart cath for PG, LVEDP and trasmitral PG for concurrent MS (Sones catheter/ 0.35-inch guidewire via transbrachial artery; pigtail/straight guidewire; transseptal approach)
Aortography is helpful in evaluating AS combined with AR

44. Aortic regurgitation
Large stroke volume produces elevated SBP and regurgitation reduces DBP
Aortic and LV pressure may equalize in diastolediastasis
AR elevated LV pressure in diastole premature closure of MV especially acute AR

45. Diastole diastasis between LV and FA
High late LVEDP exceed LA and PAWP  premature MV closure

46. Acute Versus Chronic AR
Widened pulse pressure  chronic
Tachycardia acute
Peak systolic FA pressure may exceed central aortic pressure by mmHg

48. Angiographic Accessment
1+ cleared by each beat and never fills the ventricle
2+ faint opacification of the entire LV
3+ equal opacification as LV
4+ complete, dense opacification of LV chamber in one beat and denser than ascending aorta

49. Catheterization Protocol
Right heart cath
Left heart cath
LV angigraphy, Aortography and selective coronary angiography
If resting hemodynamics are normal, consider stress intervention such as dynamic exercise

50. Tricuspid Regurgitation
Functional TR RV dilatation and failure due to pulmonary hypertension (MS, cardiomyopathy, PPH, cor pulmonale or pulmonary embolism)
Organic TR disease of valve and its apparatus due to IE, RHD or RV infarction

51. Hemodynamic Assessment
In severe TR, The morphology of RA wave is likely as RV wave

52. D/D functional or organic TR
Generally, in severe TR
If RV pressure> 60mmHg functional
If RV pressure< 40mmHg organic

53. Angiographic Assessment
RV ventriculography in RAO view
Grollman, pigtail and Eppendorf catheter situated in middle RV or RVOT with injection rate of 12-18ml/sec
Severity is similar as AR and MR

54. Tricuspid stenosis Stenosis of a prosthetic TV accounts for most cases
Blunting or absence of y descent
Pandiastolic PG across TV exist and usually small (4-8 mmHg)
TS is usually of clinical and hemodynamic significance when TV area is < 1.3 cm2

55. Pulmonary stenosis and regurgitation
PS is a congenital heart disease
PR is usually functional and a consequence of severe pulmonary hypertension
Cardiac echo is far superior to angiography in assessing PR

56. Evaluation of prosthetic valves
For retrograde crossing of a porcine AV, a pigtail catheter is highly effective.
Antegrade crossing of a porcine TV, a balloon –floating catheter is highly effective
Retrograde crossing of a ball-valve in aortic position, a 7-8F Sones catheter with or without guidewire assistence is effective
Bjork-Shiley valve and low-profile disc valve must not be crossed retrograde.

57. Thanks for Your Attention