David Letterman s Top 10 Aortic Stenosis The victim can be anyone: Echo is the question and the answer!!!! Hilton Head Island Echocardiography Conference 2012 Timothy E. Paterick, MD, JD, MBA Christopher Kramer, RDCS Aurora Cardiovascular Services Milwaukee, WI AORTIC VALVE STENOSIS Narrowing of aortic valve orifice secondary to failure of the valve leaflets to open adequately Obstruction i of flow at the level l of the aortic valve Most common adult heart valve condition Common Cause of cardiovascular morbidity and mortality Congenital Rheumatic Degenerative Etiology Congenital Unicuspid Etiology Bicuspid Quadricuspid Bicuspid Aortic Valve Stenosis More prone to calcification than normal aortic valves Most common cause of AS in patients younger then 70 50% develop at least mild AS by age 50 Cusp fusion Right and left most common ( 80%) Right and non coronary cusp (20%) Left and non coronary cusp is rare 1
Echo features of BAV Systolic Doming Eccentric closure Thickened (may be mild) Abnormal appearance (football) Possible coarctation of the aorta Post stenotic dilitation Dilated ascending AO Rheumatic Aortic Valve Stenosis Not common in industrialized countries More common in developing countries Isolated Rheumatic aortic stenosis is very rare Occurs with mitral stenosis Characterized by commissural fusion resulting in triangular systolic orifice Rheumatic Aortic Valve Stenosis Calcific Aortic Valve Stenosis Most common cause of aortic stenosis age > 70 Affects approximately 2 to 3 % of population age > 70 Risk factors are those of atherosclerotic heart disease Calcification of aortic cusps Calcific (Acquired) Aortic Valve Stenosis 2
Physical Exam: Letterman s #1 Systolic ejection murmur Heard at the right sternal border Crescendo - decrescendo murmur Rdit Radiates to carotids Loudness of murmur Severity of AS Slow rising, late peaking carotid pulse Dizziness Weakness Syncope Dyspnea Palpitations Fatigue Symptoms Edema Chest pain Paroxysmal nocturnal dyspnea Congestive heart failure Many of these symptoms will increase with exertion Visual Assessment Appearance of aortic valve: study and describe the morphology of the valve Thickness and Calcification Reduced mobility Commissural fusion Number of cusps Raphe if present VISUAL ASSESSMENT PARASTERNAL LONG AXIS Zoom Mode 3
VISUAL ASSESSMENT PARASTERNAL SHORT AXIS Higher parasternal window may be necessary for evaluation of the ascending aorta AO ROOT, SINUSES and ASCENDING AORTA 4
M-mode Decreased excursion of the cusps Calcification/thickening throughout cardiac cycle Asymmetric closure (bicuspid) Normal Aortic Stenosis Parasternal long axis Zoom mode Adjust gain Measure in mid systole Measure inner edge to inner edge from the junction of the AV leaflets to the septal wall and the AV leaflets to the MV 2.2 CM PITFALLS: POOR VISUALIZATION MEASUREMENT SITES GAINS 5
Dimensionless Index for evaluation of aortic stenosis Ratio of VTI (LVOT) to VTI (AV) Ratio Rti of f<025i <0.25 is generally rll consistent it t with severe aortic stenosis Ratio of >0.3 with mild or moderate aortic stenosis Measurement Sites I MEASURE THE LVOT DIAMETER WHERE???? 2.5 cm 1.6cm 6
1.8cm 2.5cm GAIN SETTINGS 2.2cm 17 1.7 cm ADJUST GAIN Importance of an accurate LVOT diameter measurement This measurement is squared 22 2.2 cm AVA 2.2cm 2 = 2.5 2 X.785 x 1.1 / 2.4 AVA.92 cm 2 = 1.6 2 X.785 x 1.1 / 2.4 AVA 1.16cm 2 = 1.8 2 X.785 x 1.1 / 2.4 AVA 1.7cm 2 = 2.2 2 X.785 x 1.1 / 2.4 AVA 1.0cm 2 = 1.7 2 X.785 x 1.1 / 2.4 7
Imaging Guidelines LVOT TVI LVOT TVI Pulse wave Doppler (PW) Sample volume away from area of flow convergence Parallel to flow Adjust baseline and scale APICAL FIVE OR LONG AXIS Increase sweep speed Lower filters Obtain and trace the modal velocity NOT PARALLEL 8
PFV LVOT =.96 m/s PARALLEL TO FLOW PARALLEL TO FLOW PFV LVOT = 1.11 m/s LVOT TVI Sample placement Doppler Assessment Flow Convergence Increased LVOT TVI / velocity Correct LVOT TVI / velocity 9
Sample volume placed into area of flow convergence LVOT PFV = 1.57 m/s SAMPLE VOLUME INTO LV LVOT PFV =.76 m/s Correct sample placement PFV LVOT 1.1 m/s Aortic stenosis jet velocity Mean transvalvular gradient Aortic Valve area by Continuity equation CW DOPPLER Imaging Guidelines AV TVI TVI AV Continuous wave Doppler (CW) Parallel to flow Non guided CW (Pedoff) Assess from multiple imaging windows Used in the continuity equation 10
Multiple Imaging Windows AV MG = 100 mmhg AVA = 0.7 cm2 AV MG = 51 mmhg AVA = 1.0 cm2 Optimize doppler signal Adjust gains and filter Adjust the baseline and scale Increase the sweep speed Trace CW doppler signal Outer edge of the dense signal curve AS Jet Velocity Transvalvular Mean Gradient Antegrade systolic velocity across the aortic valve CW Doppler jet measured in m/sec > 4.0 m/sec * consistent with severe aortic stenosis (Assumes normal cardiac output) Assumes normal cardiac output Difference in pressure between the left ventricle and aorta in systole Average gradient across the aortic valve during entire systole Simplified Bernoulli equation is used at several velocity points and averaged Reported in mmhg Valve Gradient Valve Gradient 0.5 m/s 2.5 m/s 3.75 m/s 4.25 m/s 475m/s 4.75 5.0 m/s 4.75 m/s 4.25 m/s 4.0 m/s 3.75 m/s 2.75 m/s 1.75 m/s 0.5 m/s 4 (0.5) 2 = 4 (2.5) 2 = 4 (3.75) 2 = 4 (4.25) 2 = 4(475) (4.75) 2 = 4 (5.0) 2 = 4 (4.75) 2 = 4 (4.25) 2 = 4 (4.0) 2 = 4 (3.75) 2 = 4 (2.75) 2 = 4 (1.75) 2 = 4 (0.5) 2 = 0.5 1 mmhg m/s 2.5 25 mmhg m/s 3.75 56.25 m/s mmhg 4.25 72.25 m/s mmhg 475m/s 4.75 90.25 mmhg 5.0 100 m/s mmhg 4.75 90.25 m/s mmhg 4.25 72.25 m/s mmhg 4.0 64 mmhg m/s 3.75 56.25 m/s mmhg 2.75 30.25 m/s mmhg 1.75 12.25 m/s mmhg 0.5 1 mmhg m/s 11
Doppler Mean Gradient 4 (0.5) 2 = 4 (2.5) 2 = 4 (3.75) 2 = 4 (4.25) 2 = 4 (4.75) 2 = 4 (5.0) 2 = 4 (4.75) 2 = 4 (4.25) 2 = 4 (4.0) 2 = 4 (3.75) 2 = 4 (2.75) 2 = 4 (1.75) 2 = 4 (0.5) 2 = 1 mmhg 25 mmhg 56.25 mmhg 72.25 mmhg 90.25 mmhg 100 mmhg 90.25 mmhg 72.25 mmhg 64 mmhg 56.25 mmhg 30.25 mmhg 12.25 mmhg 1 mmhg } 52 mmhg Aortic Valve Area Continuity Equation AORTIC VALVE STENOSIS Calculation of aortic valve area EOA < 1.0 cm 2 considered severe Measurements required LVOT diameter LVOT Velocity/TVI AV Velocity/TVI Formula: AVA = (CSA LVOT X LVOT TVI aesc Guidelines. baha/acc Guidelines TVI AV Advantages of using Continuity Equation for calculation of AS Independent of flow, can be used to calculate area with AI, high or low output states Measures effective orifice area Can be uses in most patients Calculations have been validated in clinical studies Reliable parameters for prediction of clinical outcome and clinical decision-making 12
PITFALLS/LIMITATIONS Requires three measurements More room for error LVOT diameter is squared Greatest potential source for error Irregular rhythms Need to take multiple measurements Technically difficult study LVOT VTI assumes laminar flow Equation can t be used with LVOT obstruction 13