chapter 10 calculation of stenotic valve orifice area presenter: 李政翰 supervisor: 詹世鴻

Chapter 10 Chapter 10 Calculation of Stenotic Valve Calculation of Stenotic Valve

Orifice AreaOrifice AreaPresenter:Presenter: 李政翰李政翰Supervisor:Supervisor: 詹世鴻詹世鴻

Gorlin’s FormulaGorlin’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

Gorlin’s FormulaGorlin’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

Mitral Valve AreaMitral Valve Area• A=F/(C)*44.3*h½ h=x(F/A)2 F=CO/(HR)(DFP) h=x

[CO/(HR)(DFP)A] 2

Example of Calculation of MS Example of Calculation of MS • CO=4680 cm3 /min, HR=80 beats/min

DFP=0.4 sec/beat MVA=0.71cm2

PitfallsPitfalls

• Pulmonary Capillary Wedge Tracing

NishimuraNishimura 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

PitfallsPitfalls

• 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

PitfallsPitfalls

• Alignment Mismatch

There is a time delay in the transmission of LA pressure.

• Realignment of a wedge tracing is practically more physiologic realignment

PitfallsPitfalls

• Calibration Errors

• Cardiac Output determination

CO should be measured simultaneously with the gradient determination

MR and TR would make CO measurement inaccurate

Aortic Valve AreaAortic Valve Area

• Critical Stenosis ~0.7cm2

Critical abrupt worsening of prognosis

• PG=x[CO/(HR)(SFP)A] 2

Aortic Valve AreaAortic Valve Area

• Critical Valve stenosis may be determined by body size

ExampleExample

• 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

Is peripheral arterial pressure a satisfactory substitute Is peripheral arterial pressure a satisfactory substitute for ascending aortic pressure when measuring aortic for ascending aortic pressure when measuring aortic

valve gradients?valve gradients?

Pressure tracings recorded from two catheters Pressure tracings recorded from two catheters within the body of the LVwithin the body of the LV

• If catheter tip in LVOT, it may underestimate the true LV-aorta PG up to 30mmHg

PG recorded at different sites may vary widelyPG recorded at different sites may vary widely

• The differences in PG among

different sites are up to 45mmHg

Another approach to increasing the Another approach to increasing the accuracy of transaortic valve PGaccuracy of transaortic valve PG

PitfallsPitfalls

• Transducer calibration

• Since in the absence of peripheral stenosis, mean pressure recorded by both catheters should be identical

PitfallsPitfalls

• 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)

Area of TV and PVArea 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

Alternatives to the Gorlin FormulaAlternatives 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

Assessment of AS in patients with Assessment of AS in patients with low cardiac outputlow 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

Assessment of AS in patients with Assessment of AS in patients with low cardiac outputlow cardiac output

• There are two conditions we should distinguish

a. intrinsic LV dysfunction combines with

mild AS

b. critical AS related LV dysfunction

Valve ResistenceValve Resistence

• AV resistence=

1.33(mean PG)(SEP)(HR)/CO

less flow-dependent, may be an important adjunct in patients with low CO

Recommendation of AS in patients Recommendation of AS in patients with low cardiac outputwith 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

Chapter 29 Profiles in Chapter 29 Profiles in Valvular Heart DiseaseValvular Heart Disease

Hemodynamic and Angiographic Hemodynamic and Angiographic findingsfindings

Mitral StenosisMitral 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

Catheterization ProtocolCatheterization Protocol

• Indication: consider balloon mitral valvuloplasty or MVR

• Procedure of right and left sided heart should be evaluated


• 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


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

Mitral RegurgitationMitral Regurgitation

• Mitral valve apparatus leaflets, papillary muscles, chordae tendineae and annulus

• Rheumatic heart disease, IE, MVP, AMI, LV dilatation

MRMR

• 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

Hemodynamic assessmentHemodynamic 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

Giant V wave

Exercise HemodynamicsExercise 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

Angiographic AssessmentAngiographic Assessment

• LV angiography evaluate the severity of MR

Mild (1+) clear with each beat Moderate (2+) does not clear with each beat a

nd 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

Regurgitation FractionRegurgitation 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 20-40%• Grade III 41-60%• Grade IV >60%


• 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

Aortic StenosisAortic Stenosis• Valvular, subvalvular and supravalvular• LV hypertrophy AS related• Indications for cath

LV failure, angina, syncope

Hemodynamic assessmentHemodynamic assessment

• Simultaneous measurement of pressure and flow across the AV

Carabello’s signCarabello’s sign

• LV catheter pullback in severe AS (AV area <= 0.6 cm2 ) would increase 5 mmHg in peripheral artery

Angiographic assessment 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


• 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

Aortic regurgitationAortic regurgitation

• Large stroke volume produces elevated SBP and regurgitation reduces DBP

• Aortic and LV pressure may equalize in diastolediastasis

• AR elevated LV pressure in diastole premature closure of MV especially acute AR

Diastole diastasis between LV and FA

High late LVEDP exceed LA and PAWP premature MV closure

Acute Versus Chronic ARAcute Versus Chronic AR

• Widened pulse pressure chronic

• Tachycardia acute

• Peak systolic FA pressure may exceed central aortic pressure by 20-50 mmHg

Angiographic AccessmentAngiographic 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


• 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

Tricuspid RegurgitationTricuspid 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

Hemodynamic AssessmentHemodynamic Assessment

In severe TR, The morphology of RA wave is likely as RV wave

D/D functional or organic TRD/D functional or organic TR

• Generally, in severe TR

If RV pressure> 60mmHg functional

If RV pressure< 40mmHg organic

Angiographic AssessmentAngiographic 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

Tricuspid stenosisTricuspid 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

Pulmonary stenosis and regurgitatiPulmonary stenosis and regurgitationon

• 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

Evaluation of prosthetic valvesEvaluation 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.

Thanks for Your AttentionThanks for Your Attention

chapter 10 calculation of stenotic valve orifice area presenter: 李政翰 supervisor: 詹世鴻

Documents