Valvular Heart Disease II: The Aortic Valve

Valvular Heart Disease II: The Aortic Valve Laura Wexler, M.D. 475-6383 wexlerl@ucmail.uc.edu

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Reference Sources for Valvular Heart Disease Reading: Harrison, 14th Edition p 1311-1323 Computer:♥Umedic: Aortic stenosis, aortic regurgitation, mitral stenosis, mitral regurgitation ♥Instructional Programs: Heart Sounds and Murmurs

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Case: An active 75 yo farmer comes to your office after experiencing a fainting spell while baling hay. The episode occurred without warning and he had no symptoms following the episode. However, on close questioning he admits to some breathlessness and vague chest heaviness with his usual heavy exertion over the past few months. He has been healthy all his life, doesn’t smoke and has not seen a doctor in 30 years. He served in the army in 1942; no abnormalities were reported during his induction physical.

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Physical Exam Robust looking older man. BP 135/90 P 68 bpm, regular RR-12 T-98.6° F JVP 6 cm with normal “a” and “v” waves Carotids: Difficult to palpate, delayed upstroke Lungs: Clear Heart: Palpation: Palpable “thrill” over the mid LSB. PMI 5 ICS, 2 cm lateral to the MCL. Palpable presystolic impulse followed by a sustained ventricular lift. Auscultation: Loud S S is normal. A single S (P2) is heard at the 4. 1 2 upper left sternal border but no A is heard at the lower left sternal border. 2 There is a 4/6 systolic ejection murmur (crescendo-decrescendo) heard best at the R 2nd interspace that radiates widely to the LSB, and to the neck. No diastolic murmurs. Ab domen and extremities are unrem arkable.

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Aortic Stenosis

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N N o o r r m m a a B B u u r r n n s: s: Aortic Stenosis: Etiology ♥Congenital bicuspid aortic valve ♥Rheumatic aortic valve disease ♥Calcific (senile) aortic stenosis

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Pathophysiology of Aortic Stenosis ♥ Left ventricular outflow obstruction LV systolic pressure > aortic pressure ♥ Concentric left ventricular hypertrophy Sustains high LV pressures Normalizes wall stress (radius x pressure/wall thickness) Eventually results in impaired LV diastolic compliance ♥ LA hypertrophy and enlargement♥ Severe stenosis: Limits ability to increase stroke volume on demand Critical aortic stenosis = fixed cardiac output

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Key Physical Findings in Severe Aortic Stenosis ♥ Carotid impulse: “parvus et tardus”♥ JVP: Prominent “a” wave♥ Heart: Systolic thrill Palpable presystolic impulse (S ) 4 Sustained apical systolic impulse S4 Coarse late peaking systolic ejection murmur (may radiate to neck and/or LSB) Attenuated/absent aortic component of S2

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Natural History of Aortic Stenosis ♥ Long asymptomatic “latent” period♥ “Cardinal” symptoms of severe aortic stenosis DyspneaAnginaSyncope ♥ Sudden death♥ Left ventricular dilatation and contractile failure♥ Endocarditis♥ Arrhythmias Ventricular tachycardiaConduction system diseaseAtrial fibrillation

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Natural History of AS

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Mechanisms of Dyspnea in Aortic Stenosis ♥LVH → diastolic dysfunction ♥Progressive LV dilation and contractile failure → systolic dysfunction

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Mechanisms of Anginal Chest Pain in Aortic Stenosis ♥Increased wall stress → increased myocardial O demand, exceeds 2 ability to coronary flow to meet demand ♥Associated coronary artery disease

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Mechanisms of Syncope in Aortic Stenosis ♥Fixed cardiac output: Vasodilation (exercise, vagal stimulation, drug induced), inability to augment CO, drop in cerebral perfusion pressure. ♥Heart block: Ca++ deposits in aortic ring encroach upon conduction tissue ♥Ventricular arrhythmias (LVH, ischemia)

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Diagnostic Studies in Aortic Stenosis ♥ ECG: LVH with repolarization changes “strain pattern” ♥ Chest X-Ray: Aortic root dilation (aortic valve Ca++) ♥ Echo: Aortic valve thickening and restricted motion ♥ Doppler: Gradient across aortic valve and aortic valve area can be estimated from increased flow velocity across aortic valve ♥ Cath: Measure gradient across aortic valve and calculate valve area

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Aortic Stenosis

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Treatment of Aortic Stenosis ♥ Mild to moderate asymptomatic aortic stenosis: Close follow up: History and physical exam, serial echocardiograms Endocarditis prophylaxis ♥ Severe, symptomatic aortic stenosis (1 year survival 57%) Aortic valve replacement with either mechanical or bioprosthetic valve – Ten year survival ~75%- Complications of prosthetic heart valves: infection, thromboembolism, mechanical failure ♥ Severe, symptomatic aortic stenosis NOT surgically treatable: Palliative option: aortic balloon valvuloplasty

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CASE: A 52 yo salesman is referred to you for evaluation of a heart murmur. He had applied for a pilot’s license and was denied because of the murmur. He is asymptomatic and physically active. He denies chest pain, dyspnea or dizzy spells and gives no history of a murmur being mentioned during his last physical exam five years ago. He has no family history of heart disease. He has never had high blood pressure or diabetes, doesn’t smoke, and takes no medications. A lipid profile done five years ago was reported to be “OK”.

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Physical Exam BP – 145/45 P – 78 reg RR – 12 Temp:98.6FCarotids: Very brisk with sharp collapse JVP: 5 with normal ‘a’ and ‘v’ waves Lungs: ClearHeart: Palpation: PMI is enlarged (4fb), in the anterior axillary line Auscultation: S normal, S soft. A 2/6 early peaking 1 2 systolic ejection murmur at the upper RSB and a 3/6 holodiastolic blowing murmur, heard best at the lower LSB when you ask the patient to hold his breath in expiration and lean forward. There is a different 2/6 low- pitched diastolic murmur at the apex. Pulses are all very prominent and brisk; audible pulse over the femoral arteries

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Additional Testing ECG: LVH with massive voltage in the lateral precordial leads (V4-V6) Chest X-Ray: Large heart, predominant left ventricular enlargement. No congestive heart failure. Echo: Marked left ventricular dilation, estimated EF 65%. The end diastolic dimension is 65 mm and the end diastolic dimension is 55 mm. Aortic valve: bicuspid and thickened. Doppler: Severe aortic regurgitation. The aorta is slightly enlarged (4.2 mm). *

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Major Causes of Aortic Regurgitation Leaflet Dysfunction Aortic Root Dilation Rheumatic fever Systemic hypertension Endocarditis Dissecting aneurysm Trauma Aortitis (syphilis) Bicuspid aortic valve Reiter’s syndrome Rheumatoid arthritis Ankylosing spondylitis Myxomatous degeneration Ehlers-Danlos Ankylosing spondylitis Osteogenesis imperfecta Marfan’s syndrome Pseudoxanthoma elasticum Fenfluramine-phentermine Marfan’s syndrome Annulo-aortic ectasia

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Aortic regurgitation

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Physical Findings in Aortic Regurgitation ♥ Wide pulse pressure: ♥ Bounding pulses♥ Soft aortic second sound (A )2♥ Early diastolic murmur (blowing) immediately after A2 Upper RSB with root dilationMid to lower LSB with leaflet dysfunction ♥ Systolic murmur at base (similar to aortic stenosis)♥ Austin Flint murmur: mid to late diastolic “rumble” at apex *

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Some Really Neat Physical Findings in Severe Chronic Aortic Regurgitation ♥ deMusset’s sign: Head bob with each systolic pulsation♥ Corrigans’s pulses: “Pistol shot” pulses over femoral artery♥ Mueller’s sign: Pulsation of the uvula♥ Duroziez’s sign: Systolic/diastolic bruit over femoral artery ♥ Quincke’s pulses: Capillary pulsations seen in the nailbeds ♥ Becker’s sign: Pulsation of retinal arteries and pupils♥ Hill’s sign: Popliteal BP exceeds brachial BP by > 60 mmHg

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Acute vs. chronic aortic regurgitation

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Pathophysiology of Chronic Aortic Regurgitation ♥ Slowly progressive diastolic volume overload♥ Augmented stroke volume with rapid runoff Increased systolic pressure with low diastolic pressure: wide pulse pressure ♥ Progressive left ventricular dilation, some hypertrophy ♥ Increased diastolic compliance with maintenance of normal diastolic pressures initially ♥ Late systolic failure with reduced ejection fraction and CHF

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Acute Aortic Regurgitation ♥ Sudden diastolic volume overload without LV dilation: – Acute elevation in left ventricular diastolic pressure pulmonary edema- Acute LV systolic failure  hypotension ♥ Provide inotropic support, vasodilator therapy if tolerated, urgent valve replacement.

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Natural History of Chronic Aortic Regurgitation ♥ Long asymptomatic phase; may be decades long. ♥ Left ventricular systolic dysfunction ( decline in EF) NOTE!! LV dysfunction may occur in the absence of symptoms ♥ Symptoms associated with LV dysfunction: – Exercise intolerance – Dyspnea on exertion ♥ Angina (rare)♥ Sudden death (rare)

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Natural history of aortic regurgitation

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Factors Influencing Severity of Aortic Regurgitation ♥Size of regurgitant orifice ♥Gradient across aortic valve in diastole (i.e. worse AR with high diastolic BP) ♥Duration of diastole

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Management of Chronic Aortic Regurgitation ♥ Close follow up of left ventricular size and function with serial echocardiograms (Every few years with mild AR, every 6-12 months with severe AR) ♥ Endocarditis prophylaxis♥ Medical therapy: Vasodilator therapy: reduces blood pressurereduces regurgitant volume Delays need for aortic valve replacement Digoxin (enhance systolic function) Diuretics (reduce LA pressure) Do NOT slow heart rate!♥ Aortic valve replacement with mechanical or bioprosthetic valve

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Criteria for Aortic Valve Replacement in Chronic Aortic Regurgitation ♥ Symptoms Congestive heart failure Declining exercise tolerance on exercise testing Angina ♥ Anatomy, regardless of symptoms: Left ventricular dysfunction: EF <50%Progressive left ventricular dilation or decline in EF on serial studiesSevere dilation (echo): – Left ventricular diastolic dimension >75 mm – Left ventricular systolic dimension >55 mmAortic root dimension >50 mm

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Right Sided Valve Disease: Read Harrison, 14th Edition: Pages 1322-1323 ♥Tricuspid stenosis ♥Tricuspid regurgitation ♥Pulmonic stenosis ♥Pulmonic regurgitation

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