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IMAGING CONFERENCE: AORTIC REGURGITATION September 16, 2009 Ali R. Rahimi, MD MPH.

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Presentation on theme: "IMAGING CONFERENCE: AORTIC REGURGITATION September 16, 2009 Ali R. Rahimi, MD MPH."— Presentation transcript:

1 IMAGING CONFERENCE: AORTIC REGURGITATION September 16, 2009 Ali R. Rahimi, MD MPH

2 Patient A: What is the Story?

3 Patient B: What is the Story ?

4 Patient B:

5 Patient A:

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8 Patient B:

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13 Diagnosis  Patient A  48 yo M PMH cocaine induced aortic arch dissection s/p repair c/b recurrent VRE AV (Bicuspid) Endocarditis and 2-3+ AR Mobile vegetation on LVOT side of Posterior Leaflet  Patient B  47 yo M PMH AV (Bicuspid) Endocarditis c/b 4+ AR Two separate, mobile, moderate-sized vegetations (0.8cm x 0.5cm, 0.6cm x 0.6cm) located on the two leaflets of the aortic valve which prolapse across the LVOT during systole (larger vegetation on posterior leaflet)

14 Aortic Regurgitation  Diastolic reflux of blood from Aorta  LV  Incidence of clinically significant AR increases with age  Typical peak in 4 th to 6 th decade of life  More common in men than women  Prevalence 4.9% in Framingham Heart Study  Congenital or Acquired  Caused by abnormalities of aortic root or AV

15 Etiology  Dilation of Aortic Root and Annulus  Hypertension  Marfan Syndrome  Syphilitic Aortitis  Cystic Medial Necrosis  Aortic Dissection  Osteogenesis Imperfecta  Ankylosing Spondylitis  Ehlers-Danlos Syndrome ≥ 2mm dilation at sinotubular junction can cause AR

16 Etiology  Aortic Valve  Bicuspid Aortic Valve  Rheumatic Heart Disease  Degenerative Calcific AV Disease  Infective Endocarditis  Other  Trauma  Membranous Subaortic Stenosis  Rheumatoid Arthritis  Fenfluramine and Dexfenfluramine  Deterioration of AVR Bioprosthesis

17 Acute Aortic Regurgitation  Most commonly due to endocarditis, aortic dissection, or blunt chest trauma  Sudden large regurgitant volume imposed on LV  Abrupt increase in LVEDV  Rapid increase LVEDP & LAP  Inability of ventricle to develop compensatory chamber dilatation acutely results in a decrease in forward SV  Congestive Heart Failure, Myocardial Ischemia and/or Cardiogenic Shock

18 Chronic Aortic Regurgitation Early Compensated  Enlarged chamber size  ↑ afterload  hypertrophy of LV which preserves compliance  normal filling pressures  LVH  ↑ LV mass  normal LV vol/mass ratio & EF  Progressive LV dilation and systolic HTN  ↑ wall stress and vol/mass ratio  ↑ wall stress eventually leads to overt LV dysfunction. Decompensated  LV systolic dysfunction accompanied by decreased LV diastolic compliance due to hypertrophy and fibrosis  Leads to high filling pressures and CHF symptoms  Exertional dyspnea common; angina can occur due to reduced coronary flow reserve with predominantly systolic coronary flow Courtesy: Ali Mahajerin, MD

19 Stages Bekerdjian R, et al. Circulation 2005; 112: 125-134

20 Physical Exam - Auscultation  A2 often soft/absent, P2 normal  S3 if LV function severely depressed  High frequency decrescendo diastolic murmur over the 3 rd or 4 th intercostal space at left sternal border  Best heard sitting up, leaning forward at end expiration  Austin Flint murmur: mid-to-late diastolic apical rumble, possibly due to vibration of anterior mitral leaflet as it is struck by a posteriorly directed AR jet.

21 Physical Exam - Peripheral Findings  Corrigan’s pulse – bounding “waterhammer” carotid pulse  deMusset’s sign – head bob with each heart beat  Mueller’s sign – systolic pulsation of uvula  Traube’s sign – pistol shot pulse over the femoral artery  Duroziez’s sign – systolic and diastolic bruits heard when femoral artery partially compressed  Becker’s sign – visible pulsations of retinal arteries and pupils  Hill’s sign – popliteal cuff systolic pressure exceeding brachial pressure by more than 60 mmHg  Mayne’s sign – more than 15 mmHg decrease in diastolic blood pressure with arm elevation  Rosenbach’s sign – systolic pulsations of the liver  Gerhard’s sign – systolic pulsations of the spleen

22 Diagnosis and Initial Evaluation Class 1  Echo: confirm presence and severity of acute or chronic AR. (Level of Evidence: B)  Echo: diagnosis and assessment of the cause of chronic AR (including valve morphology and aortic root size and morphology) and for assessment of LV hypertrophy, dimension (or volume), and systolic function. (Level of Evidence: B)  Echo: in patients with an enlarged aortic root to assess regurgitation and the severity of aortic dilatation. (Level of Evidence: B)  Echo: periodic re-evaluation of LV size and function in asymptomatic patients with severe AR. (Level of Evidence: B)  Echo: re-evaluate mild, moderate, or severe AR in patients with new or changing symptoms. (Level of Evidence: B)  **Radionuclide angiography or MRI: initial and serial assessment of LV volume and function at rest in patients with AR AND suboptimal echocardiograms. (Level of Evidence: B) Bonow, R. O. et al. J Am Coll Cardiol 2008;52:e1-e142

23 M-Mode Imaging  Aortic jet across anterior MV creates  High-frequency fluttering requiring rapid sampling rate  Increased duration between E and A peaks  Increased distance between the maximal anterior motion of MV in early diastole (E point) and the most posterior motion of the IVS (e.g., increased E-point septal separation)  Acute AR  premature closure of MV  Rapidly increasing LVEDP

24 M-Mode Imaging

25 2-Dimensional Imaging  Focus on AV and Root  Endocarditis  Dissection  Dilation  Perivalvular leaks around aortic prosthesis  Assessment of LV size and function  Dilation  Response to volume overload

26 2-Dimensional Imaging AVR - Dilated Aortic RootMarfans - Dilated Aortic Root

27 2-Dimensional and Color Flow Aortic Regurgitation due to AV Endocarditis

28 2-Dimensional and Color Flow AV Prosthesis: Aortic Root Abscess and Perivalvular Regurgitation

29 2-Dimensional and Color Flow LV Dilated-Spherical due to Chronic Severe Aortic Regurgitation

30 Doppler Imaging: Color Flow  Critical since 2-D may at times be “unremarkable” despite severe aortic regurgitation  Most common technique to visualize AR  Sensitivity > 95%  False negatives can occur in tachycardia with mild AR Frame rate allows only a few diastolic frames to be displayed  Can be overcome by using CW -- has a higher sampling rate  Specificity ~100%  Detects even trivial AR  Less than1% of normal subjects under age 40  10-20% of patients greater than age 60  Vast majority of individuals greater than age 80

31 Doppler Imaging: Color Flow  Composed of 3 distinct segments:  Proximal flow convergence zone = area of flow acceleration into the orifice  Vena contracta = narrowest and highest velocity region of the jet at or just downstream from the orifice  The jet itself occurs distal to the orifice in the LV cavity  Measurement of the jet area or penetration into the LV cavity is not accurate in assessing AR severity, though:  If jet width/LVOT width < 25%  specific for mild AR  If jet width/LVOT width > 65%  specific for severe AR  This works best when regurgitant orifice is relatively round in shape.

32 Doppler Imaging: Vena Contracta  The narrowest diameter of flow stream  Independent of volume flow rate and driving pressure, relatively unaffected by instrument settings  Narrow range of values though, so care needed to obtain optimal images. Ideal sample is:  Perpendicular to jet width  In zoom mode  Narrow sector  Minimum depth  For AR, vena contracta can be measured in parasternal long-axis view preferably in zoom mode

33 Doppler Imaging: Vena Contracta  Vena contracta width of ≥ 6 mm correlates with severe AR (sensitivity 95%, specificity 90%)  Vena contracta width of < 3 mm specific for mild AR Enriquez-Sarano M, et al. NEJM 2004; 351: 1539-1546.

34 Doppler Imaging: Color Flow MildModerateSevere

35 Doppler Imaging: Color Flow Jet Width/LVOT Width < 25% Mild MR Jet Width/LVOT Width > 65% Severe AR Bekerdjian R, et al. Circulation 2005; 112: 125-134.

36 Doppler Imaging: Color Flow  Limitations as indicator for AR severity:  Eccentric jets entrained along LV wall  Jet is 3-D thus need multiple planes  Changes in instrument gain, color scale, transducer frequency and wall filters will affect AR appearance, independent of severity  ROA in chronic AR usually decreases during diastole Thus temporal variability Tendency to overestimate since visualized jet area would reflect peak rather than mean orifice area

37 Doppler Imaging: Pulsed Wave  Relies on demonstration of turbulent flow in LVOT on ventricular side of AV  Due to high AR velocity, aliasing occurs, with prescence of turbulence establishing the diagnosis  Highly sensitive but requires methodical search for AR  False-Positive in setting of Mitral Stenosis or Prosthetic MV with turbulent diastolic flow  Assumption the AR is centrally located and can be tracked toward apex  Holodiastolic flow reversal in descending aorta correlated with severe AR

38 2-Dimensional and Doppler Imaging Eccentric AR JetDisplacement of Anterior MV

39 Doppler Imaging: Continuous Wave  Due to high velocity AR jet, CW necessary for contour of the envelope to be recorded  Density of jet ≈ volume of regurgitation  Approximation of number of RBCs being sampled  Velocity of AR jet and Rate of Deceleration of retrograde flow can be measured  AR results in increased antegrade volume flow rate across AV, which is reflected in an increase in the antegrade velocity across the valve  The greater the severity of AR, the higher the antegrade velocity across the AV  Must also consider possibility of coexisting AS  Helpful to distinguish AR from Mitral Stenosis Jet  Based on velocity and contour of jet

40 Doppler Imaging: Continuous Wave  Compare AR signal to Antegrade Flow  Weak  mild  Equal  severe Antegrade AR

41 Doppler Imaging: CW and PHT  AR velocity reflects pressure gradient between aorta and LV throughout diastole  Early diastole – gradient is the highest with velocity 4-6 m/sec, depending on BP  Diastole progresses – gradient diminishes as aortic pressure decreases and LV pressure increases  Mild AR – compliant LV allows a slow and modest increase in LVEDP and Ao EDP is maintained throughout  AR velocity remains high and CW envelope appears flat  Severe AR – increasing LVEDP and more rapid decrease Ao pressure leads to a more rapid decel of AR velocity

42 Doppler Imaging: CW and PHT  Flat slope (P 1/2 > 500 msec)  mild AR  Steep slope (P 1/2 < 200 msec)  severe AR  Limitations of pressure half-time assessment:  Aortic compliance, BP, and LV size/compliance will affect measures  Pressure half-time sensitive to chronicity of AR Acute AR leads to much shorter values than chronic AR when LV is dilated with increased compliance Thus, a rapid P 1/2 is more indicative of acuity than severity  Pressure half-time varies with SVR Vasodilators may shorten the pressure half-time even as the aortic regurgitant fraction improves.

43 Doppler Imaging: CW and PHT Acute AR due to Aortic DissectionChronic AR due to Ca AV disease

44 Doppler Imaging: Regurgitant Volume and Fraction  Can compare flow through AV versus MV or PV  Stroke volume at any valve annulus is derived as the product of CSA and TVI of flow at the annulus  In the absence of regurgitation, SV determinations at different sites should be equal  In the presence of regurgitation of one valve, without any intracardiac shunt the flow through the affected valve is larger than the other valves  RV is the difference between the two flows  RF = RV/ Forward SV through the regurgitant valve

45 Doppler Imaging: Regurgitant Volume and Fraction  Regurgitant Volume (fraction):  Mild: < 30cc (< 30%)  Mild-Moderate: 30-44cc (30-39%)  Mod-Severe: 45-59cc (40-49%)  Severe: ≥60cc (≥50%)  Limitations:  Assumes normal flow through comparison valve  Cannot be used in presence of shunts  Sensitive to small measurement errors (measurement errors of the radius and tracing the VTI)

46 Summary: Zoghbi WA, et al. JASE 2003; 16: 777-802

47 Serial Testing by Echocardiography  If chronic nature of lesion uncertain and no initial surgical indication, should repeat exam and echo within 2-3 months after initial evaluation  Asx, mild AR, little/no LV dilation, normal LV systolic function: see yearly, echo q2-3 years  Asx, severe AR, significant LV dilation (LVEDD > 60 mm), normal LV fx: echo q6-12 months  Asx, severe AR, severe LV dilation (LVEDD > 70 mm), normal LV fx: echo q4-6 months.  Repeat echo for onset of symptoms, equivocal history of changing symptoms or exercise tolerance, or clinical findings to suggest worsening regurgitation or progressive LV dilatation. Bonow RO, et al. J Am Coll Cardiol, 2008; 52:1-142

48 Copyright ©2008 American College of Cardiology Foundation. Restrictions may apply. Bonow, R. O. et al. J Am Coll Cardiol 2008;52:e1-e142 Management Strategy for Patients With Chronic Severe Aortic Regurgitation

49 THANK YOU


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