Aortic Regurgitation: Old and New

1. Aortic Regurgitation: Old and New Andrew D. Ferguson UIC Cardiology February 7, 2008

2. Acute AR followed by Chronic Etiology Pathophysiology Natural History Diagnostic Evaluation Treatment Special Considerations Agenda

3. Endocarditis Valve destruction and leaflet perforation Paravalvular abscess rupture into LV, LA or RVOT Aortic dissection Incomplete coaptation of leaflets Flail leaflets from extension of dissection Acute AR: Etiology

4. Acute AR: Etiology • Rupture of a congenital fenestration • Traumatic rupture of leaflets after either deceleration injury or blunt trauma • Iatrogenic • Aortic balloon valvotomy • Failed surgical repair or replacement

5. Pathophysiology • Sudden, large regurgitant volume • Normal-sized ventricle unable to fully accommodate volume overload • Frank-Starling mechanism increases SV, but forward stroke volume markedly diminished (FSV=SV-Regurg volume)

6. Pathophysiology • Tachycardia is compensatory • Increase or decrease CO? • Increased LVEDP leads to: • Early closure of mitral valve • Increased LA pressures, which then lead to pulmonary edema • Myocardial ischemia • Diminished myocardial perfusion pressure

7. Pathophysiology • Pre-existing LVH (i.e. HTN, AS): • More susceptible to drastic hemodynamic consequences • Smaller, non-compliant LVs with a reduced preload reserve • Examples: • Aortic dissection in longstanding HTN • IE in pre-existing AS • Iatrogenic (i.e. valvulotomy) for congenital AS

8. Acute AR: Hemodynamics

9. Natural History • Severe acute AR generally presents with cardiovascular collapse: • Weakness • Severe Dyspnea • Hypotension • Other sxs, if present, related to etiology: • For example, chest/back pain related to aortic dissection.

10. Evaluation: Physical • Manifestations of cardiogenic shock: • Hypotension, pallor, diaphoresis, occasional cyanosis, peripheral vasoconstriction • Soft or absent S1 due to early closure of MV (increased LVEDP) • Soft A2, loud P2 • Frequently an S3, no S4 • Early diastolic, low-pitched murmur MAY be present after S2. • Systolic flow murmur (increased SV)

11. Evaluation: Imaging • CXR: CHF and pulmonary edema • CT can be used in evaluation for aortic dissection • Ultimately, echocardiography is the diagnostic procedure

12. Acute AR: Echo • Color doppler demonstrates the regurgitant flow and aids grading • Severe acute AR: • Vena contracta width >6mm • Diastolic pressure half-time <200ms • Holodiastolic flow reversal in desc. aorta • TTE/TEE to diagnose IE, dissection

13. Treatment • Death without tx is common, due to: • EMD, ventricular arrhythmias, pulmonary edema, or circulatory collapse. • Any severity of acute AR: • Urgent aortic valve replacement • If surgery delayed, may stabilize in ICU: • IV Vasodilators, i.e. nitroprusside • Possibly inotropic agents, i.e. dopamine • IABP contraindicated • Exception: Mild acute AR due to endocarditis

14. Chronic AR: Etiology • Leaflet Abnormalities: • Rheumatic fever • Endocarditis • Trauma • Bicuspid aortic valve • Rheumatoid arthritis • Myxomatous degeneration • Acromegaly • Fenfluramine-phentermine

15. Chronic AR: Etiology • Ascending root or ascending aorta: • Systemic hypertension • Aortitis (e.g. syphilis) • Reiter’s syndrome • Ankylosing spondylitis • Trauma • Dissecting aneurysm • Marfan syndrome • Ehlers-Danlos syndrome • Pseudoxanthoma elasticum • Inflammatory bowel disease • Osteogenesis imperfecta • Annuloaortic ectasia

16. Chronic AR: Epidemiology • Framingham Heart Study: • ≥trace AI found in 13% men, 8.5% women • Rarely more than trace younger than 50 • Prevalence of ≥moderate AI:

17. Chronic AR: Pathophysiology • Course of AR is insidious, often decades before clinically important • Compensatory mechanisms aimed at: • Preservation of forward stroke volume and hence cardiac output • Maintenance of normal wall stress

18. Chronic AR: Wall Stress • Large regurgitant volume leads to increase in LV end-diastolc volume • Creates elevation in wall stress • Laplace’s law: • Compensate by increasing LV thickness, both eccentric and concentric Cavity Pressure x Radius LV Wall Stress = -------------------------------- Wall Thickness x 2

19. Chronic AR: Cardiac Output • AR leads to diminshed forward stroke volume, and hence CO • FSV = SV - ARV • Increase SV to maintain FSV (CO) by: • Increase ventricular compliance (dilatation) • Maintain efficiency (hypertrophy)

20. Chronic AR: Hemodynamics

21. Clinical Manifestations • May be asymptomatic for decades • Symptoms due to enlarged LV: • Awareness of heartbeat, pounding • Atypical chest pain • Palpitations (ST, PACs, PVCs) • Symptoms of LVH with LV dysfunction • Angina

22. Chronic AR: Angina • Uncommon in isolated AR due to dilation of coronary arteries • Underlying CAD • Subendocardial ischemia • Diminished perfusion pressure • Nocturnal ischemia • Heart rate slows, arterial diastolic pressure falls. • Splanchnic ischemia may also occur, abd pain.

23. Chronic AR: Examination • Physical examination remains important both for initial diagnosis and following progression of disease • Many characteristic attributes which help grade severity/progression: • Surface exam • Auscultation • Peripheral exam

24. Chronic AR: Surface Exam • Consistent with LV enlargement and forceful systolic function • Apical impulse: • Displaced laterally and inferiorly • Diffuse and hyperdynamic • Dilatation of ascending aorta: • Sternal notch pulsation and possibly thrill

25. Chronic AR: Auscultation • Heart Sounds: • S1 soft, ?reflecting long PR interval • S2 variable; soft, absent, or single • A2 often soft or absent • P2 may be normal, increased or obscured by the diastolic murmur • S3 occasionally present due to volume overload • S4 usually absent

26. Chronic AR: Auscultation • Murmurs: • Diastolic regurgitant murmur: • Good positive and negative predictive values • Begins immediately after A2 • High-pitched, blowing, sustained or decrescendo • Best appreciated with patient sitting up, leaning forward, and holding breath in expiration • Guage severity • Intensity does not correlate to severity (may be absent) • Murmur in early diastole and blowing ---> mild AI • As lesion becomes more severe, murmur extends through more of diastole, become holodiastolic and rougher • **Beware of transient murmur of AR: • E.g. HD patients in volume overload, resolves with HD

27. Chronic AR: Auscultation • Murmurs, cont.: • Regurgitant murmur varies with squatting/Valsalva • Austin Flint murmur • Mid to late diastolic apical rumble • Results from competing flows of the mitral inflow and the regurgitant lesion • Distinguish from MS by lack of loud S1 & OS • Systolic murmur • Mainly a result of functional stenosis (SV and rate) • Cresc-decresc harsh murmur beginning after S1

28. Chronic AR: Peripheral Exam • Wide pulse pressure • Increased stroke volume • Abrupt distention of peripheral arteries • Elevation of systolic pressure • Regurgitation into LV • Quick collapse of arteries • Low diastolic pressure • Many non-specific peripheral signs

29. Quincke’s sign: capillary pulsation Corrigan’s sign: water hammer pulse Bisferiens pulse (AS/AR > AR) De Musset’s sign: systolic head bobbing Mueller’s sign: systolic pulsation of uvula Durosier’s sign: femoral retrograde bruits Traube’s sign: pistol shot femorals (auscultation) Hill’s sign:BP Lower extremity >BP Upper extremity by > 20 mm Hg - mild AR > 40 mm Hg – mod AR > 60 mm Hg – severe AR Peripheral Signs of Severe AR

30. Chronic AR: ECG • LVH • Evidence of LA hypertrophy • Leftward axis • ST segment depression • One study showed 83% of patients with rest or exercise ST abnl had enlarged ventricle (>55mm) or low EF (<45%) • Arrhythmias/conduction abnl uncommon

31. Chronic AR: Echo

32. Chronic AR: Echo • Characteristic Findings: • If primary valvular, can see leaflet thickening, vegetations, calcification, and prolapsed or flail leaflets • Aortic root dilatation or evidence of aneurysm (either dissecting or saccular) • High frequency, diastolic fluttering of anterior mitral leaflet from AR jet • Doppler is highly sensitive for detecting AR jet • Increased LVESV and LVEDV

33. Chronic AR: Severity Assessment • Severe AR present by echo with at least one of the following findings: • Regurgitant fraction ≥50% • Vena contracta width >6mm • Regurgitant volume ≥60mL • Central jet width ≥65% OF LVOT • ERO area ≥0.30cm2

34. Chronic AR: Echo Severity • Other indirect measures: • Rate of decline in regurgitant slope • The sharper the decline, the more severe • Degree of reversal in pulse wave velocity in the descending aorta • Magnitude of LV outflow tract velocity

35. Chronic AR: Severity

36. Chronic AR: Cath • Goals: LV size and function, aortic root dimensions/disorders, quantitation of AR

37. Chronic AR: CT/MRI • Especially important with suspected aortic disease • AR due to bicuspid aortic valve may have concommitant aortic dilatation

38. Chronic AR: Natural History Asymptomatic %/Y • Normal LV function (Good prognosis) • Progression to symptoms &/or LV dysfunction < 6 • Progression to asymptomatic LV dysfunction < 3.5 • 75% 5-year survival • Sudden death < 0.2 • Abnormal LV function • Progression to cardiac symptoms 25 • Symptomatic (Poor prognosis) • Mortality > 10 Bonow RO, et al, JACC. 1998;32:1486. (593 patients, mean 6.6yrs)

39. Chronic AR: Treatment • Management depends upon: • Severity • Based on clinical and echo criteria • Symptoms • If equivocal, consider exercise testing • LV function (>50% or ≤50%) • If equivocal, consider RVG or MRI • LV dimensions (LVSD, LVDD)

40. Chronic AR: Treatment • Mild to moderate AR • Do not require treatment • Serial monitoring (symptoms, echo) • Symptomatic with mild to moderate AR • Consider other etiologies of symptoms • E.g. mitral stenosis

41. Severe AR: Management • Asymptomatic with normal LV function • First question if truly asymptomatic??? • Consider exercise testing if sedentary or equivocal symptoms • Medical therapy (i.e. vasodilators) • Not recommended • Serial monitoring • Symptoms and LV dimensions and function

42. Severe AR: Medical Therapy • Treat systemic arterial diastolic HTN • Cautious use of BB • Treat afib and bradyarrhythmias • Poorly tolerated • Treat LV dysfunction prior to surgery • Digoxin, salt restriction, diuretics, ACE/ARB • Treat angina • Nitrates not as helpful than in +CAD • Vasodilators - next slide

43. Severe AR: Theory of Vasodilators • Improve stroke volume and reduce regurgitant volume hopefully reducing: • LVEDV • Wall stress • Afterload • Results in preserved LVEF and reduction in LV mass

44. Severe AR: Vasodilators • Conflicting results of efficacy in controlled randomized trials • Most recent and only placebo-controlled • 95 consecutive patients, followed 7 years • Placebo, long-acting nifedipine, enalapril • No reduction in symptoms or LV dysfunction • No sig dif in LV dimension, EF, or mass • If used, goal is to reduce systolic BP • Not indicated in normal BP or normal LV size

45. Severe AR: Vasodilators

46. Physical Activity • Reduction in regurgitant volume from: • Decrease in PVR and resultant diastolic blood pressure • Decreased diastolic filling period which accompanies tachycardia • Failure of increased EF • Uncertain ultimate consequences

47. Physical Activity • Also recommend Holter monitoring in those who wish to perform competitive athletics to detect ventricular arrhythmias 36th Bethesda Conference, JACC 2005

48. Chronic AR: Serial Testing • Initial Presentation (mod to severe AR) • Establish stability and chronicity • If unknown, repeat exam and TTE in 2-3mos • Once stability and chronicity established, frequency of reevaluation depends on: • Severity of AR • Degree of LV dilatation • Level of systolic function • The level of progression of dilatation and/or dysfxn • Repeat eval with any hint of progression

49. Chronic AR: Surgery

50. Chronic AR: Surgical Caveats • Symptomatic severe AR with Normal LVSF: • Surgery indicated for NYHA class III-IV and Canadian class II-IV angina • NYHA class II, question etiology of symptoms (deconditioning or aging?) • Consider exercise testing