ADULT ECHOCARDIOGRAPHY Lecture Five The Aortic Valve Harry H. Holdorf PhD, MPA, RDMS, RVT, LRT, N.P.

Aortic Stenosis Etiology Calcific/degenerative (50% start as bicuspid) Rheumatic (Assoc. w/mitral stenosis) Congenital (bicuspid (1-2% of the population), membrane Supra and subvalvular obstructions Prosthetic valve dysfunction

Pathophysiology Systolic pressure overload leads to LVH (increase in afterload) Increase in LVEDP leading to increased LA pressure Ventricular dysfunction may develop late in disease course Increased risk for endocarditis Aortic sclerosis occurs when there is Valvular thickening but no hemodynamic gradient

Physical signs Symptoms of angina, dyspnea and syncope/sudden death Harsh systolic ejection murmur right upper sternal border (RUSB) crescendo-decrescendo Decreased or absent A2 (valve doesn’t move) Decreased and delayed carotid upstroke with bruit/thrill transmitted from AoV

Echo (Valvular) Thickened aortic leaflets Decreased valve opening Post-stenotic dilatation of the aorta-thought to be caused by abnormal turbulence and wall stress (remember that there is low pressure in the aorta (systolic BP) but high pressure in the LV) Left ventricular hypertrophy

A secondary finding in aortic stenosis is? Left ventricular hypertrophy In aortic stenosis, is pulse pressure wide or narrow? Narrow (pulse pressure is the difference between systolic and diastolic pressures-it is wide in AI and narrow in AS.

AHC/ACC Guidelines for Aortic Stenosis severity:

ECHO (BICUSPID) Possible eccentric closure on M-Mode (25% will have normal midline closure) Thickened aortic leaflets (may be mild) Systolic doming on LAX view Bicuspid orifice in SAX view (football) Check for coexisting Coarctation of the aorta Left ventricular hypertrophy

M-mode of a bicuspid aortic valve

2D bicuspid aortic valve

The best view to diagnose a bicuspid aortic valve is the parasternal: NOTE: The best view to diagnose a bicuspid aortic valve is the parasternal: Short-axis systole

Aortic Coarctation NOTE: Systemic hypertension is a common symptom of aortic Coarctation. Normal descAo velocity is about 1 m/sec ECHO (FIXED SUBVALVULAR) Congenital membrane or ridge in LVOT beneath AoV Early systolic closure or aortic leaflets Left ventricular hypertrophy

Sub-aortic membrane

Echo (Supra-valvular) Discrete narrowing of aortic root or ascending aorta Left Ventricular hypertrophy Doppler Use PEDOFF probe & multiple windows (suprasternal , apical, right parasternal) Increased velocity and turbulence at level of obstruction (valvular, subvalvular, supra-valvular)

Measure peak and mean gradients (take the highest) Use continuity equation for valve area if possible. Use pulsed/color flow Doppler to locate level of obstruction Mean Doppler and cath gradients correlate better than peak vs. peak to peak NOTE: What is Takayasu’s arteritis? Also called aortic arch syndrome, this disease occurs more in young women from Asia. There is fibrosis of the arch and descending Ao of unknown etiology. In advanced states, multiple coarctations may occur (look for supra-valvular AS)

Aortic velocity is 5 m/sec. Peak LV pressure in this patient is? NOTE: Patients BP = 110/84 Aortic velocity is 5 m/sec. Peak LV pressure in this patient is? 210 mm Hg Add the Ao gradient 100 mmHg if the velocity is 5 m/sec to the systolic BP.

Aortic Valve Area Normal 3.0 – 4.0 cm sq. Mild >1.5 cm sq. Mod 1.5 – 1.0 cm sq. Sev <1.0 cm sq. NOTE: The normal aortic valve area is 3-4 cm sq.

Aortic valve area calculation is an indirect method of determining the area of the aortic valve. The calculated aortic valve orifice area is currently one of the measures for evaluating the severity of aortic stenosis. A valve area of less than 0.8 cm² is considered to be severe aortic stenosis. There are many ways to calculate the valve area of aortic stenosis. The most commonly used methods involve measurements taken during echocardiography. For interpretation of these values, the area is generally divided by the body surface area, to arrive at the patient's optimal aortic valve orifice area. The continuity equation states that the flow in one area must equal the flow in a second area if there are no shunts between the two areas. In practical terms, the flow from the left ventricular outflow tract (LVOT) is compared to the flow at the level of the aortic valve. In echocardiography the aortic valve area is calculated using the velocity time integral (VTI) which is the most accurate method and preferred. The flow through the LVOT, or LV Stroke Volume (cm3 or cc), can be calculated by measuring the LVOT diameter (cm), squaring that value, multiplying the value by 0.78540 giving cross sectional area of the LVOT (cm2)and multiplying that value by the LVOT VTI(cm), measured on the spectral Doppler display using pulsed-wave Doppler. From these, it is easy to calculate the area (cm2) of the aortic valve by simply dividing the LV Stroke Volume (cm3) by the AV VTI(cm) measured on the spectral Doppler display using continuous-wave Doppler

Continuity Equation

Continuity equation NOTE: Using the continuity equation, when would the severity of AORTIC STENOSISS be underestimated? LVOT is measured too large NOTE: Measure LVOT during systole at the leaflets insertion level (Same place as sample position for PW Doppler)

Describing Severe Aortic Stenosis 1st Look at Valve area 2nd look at Max Gradient (If Valve areas are equal) 3rd Look at wall thickness (evidence of LVH)

Aortic stenosis severity

Next Lesson: The pulmonic valve Lesson Five Completed Next Lesson: The pulmonic valve