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Board Review. Vikram Chhokar MD University of Tennessee Division of Cardiology. Question.
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Board Review Vikram Chhokar MD University of Tennessee Division of Cardiology
Question • An 80-year-old Asian woman awakens at 2 a.m. feeling as if she were being smothered. She is brought to the ED and is found to be in pulmonary edema. She has a history of a heart murmur, discovered 20 years before. Prior to this episode she says she was in good health, although she has not been physically active due to arthritic discomfort for the past 5 years. On careful questioning she admits to brief episodes of pressure-like sensation in her chest especially when she becomes aggravated.
Question • Physical examination: BP 150/110 mmHg, pulse 120/min, respirations 24/min. Neck veins 10cm. Lungs have rales 3/4 the way up posteriorly bilaterally. Carotids are difficult to feel. PMI is in the 5th intercostal space just outside the midclavicular line and sustained. There is a grade II/VI systolic ejection murmur at the base and a grade II/VI diastolic blowing murmur at the 3rd left intercostal space. There is an S4 and an S3 gallop. There is no hepatomegaly and no pedal edema.
Question • Laboratory : Chest X-ray: slightly enlarged cardiac silhouette, pulmonary vascular redistribution and pulmonary edema. ECG: QS in V1, a small r in V2, a 25mm R wave in V5 and a 30mm R wave in V6. There is 2mm ST-segment depression in V4-6 . Echo: estimated EF 55%, first troponin <0.3 ng/ml. • The patient is given O2, Lasix, digoxin, and enalapril and becomes less dyspneic. Her pulse decreases to 90/min and BP to 110/85 mmHg.
Question • The most probable diagnosis in this case is: • A. Severe AR • B Severe aortic stenosis • C. Hypertensive cardiovascular disease. • D. Acute non-ST-elevation myocardial infarction. • E. Congestive heart failure with diastolic dysfunction.
Answer • The correct answer is B.The pulses and BP are against severe aortic regurgitation. Although the patient probably has angina, and even may have coronary artery disease, the presence of the systolic murmur, the poor arterial pulses, the severe LVH on ECG make aortic stenosis the likely diagnosis. Although the BP was elevated when she was in severe failure due to the excessive sympathetic stimulation and activated renin angiotensin system, when the patient was treated the BP returned to normal, inconsistent with acute heart failure due to hypertensive disease.
Aortic Stenosis • Etiology based on location • Supravalvular • Subvalvular- • Valvular
Supravalvular Aortic Stenosis • Supravalvular • Associated Elfin facies • Hypercalcemia • Peripheral pulmonic stenosis • Thrill palpation in suprasternal notch or R but not L carotid artery • Increased A2
Subvalvular Aortic Stenosis • Subvalvular • Presents with a high doppler velocity on outflow tract with normal AV on echo. • Frequent AR due to aortic valve jet • Looks like HOCM on echo with LAM • Two subtypes • Discrete- 10%, sec to subvalvular ridge • Tunnel
Valvular Aortic Stenosis • Valvular • Congenital (1-30 yrs old) • Bicuspid (40-60 yrs old) • Rheumatic (40-60 yrs old) • Senile degenerative (>70 yrs old)
Bicuspid Aortic Valve • The most common congenital cardiac abnormality is bicuspid aortic valve affecting 1-2% of the U.S. population. • Over time, one-third to one-half of such valves become stenotic, with significant narrowing of the aortic orifice typically developing in the 5th and 6th decades of life.
Aortic Stenosis Key Points • MCC of AS is senile degenerative changes • In patients with AS due to rheumatic dz r/o “silent” mitral stenosis. • Bicuspid or rheumatic should be suspected in pt with AS presenting in 5th or 6th decade of life.
Pathophysiology • Increase in afterload • Decrease in systemic and coronary flow from obstruction • Progressive hypertrophy
Classic symptom triad • Dyspnea • Angina • Syncope
Classic symptom triad • Once any of these classic symptoms develop, prognosis dramatically worsens. • Thus, within 5 years of the development of angina, approximately 50% of patients will die unless aortic valve replacement is performed. • For syncope, 50% survival is 3 years • For congestive heart failure, 50% survival is only 2 years unless the valve is replaced. • Angina 5, Syncope 3, and CHF 2.
Characteristic Physical findings • Dampened upstroke of carotid artery • Sustained bifid left ventricular impulse • Absent A2 • Late-peaking systolic ejection murmur • A concomitant systolic thrill indicates the presence of AS (mean gradient >50mm Hg) • Of note if you have significant Physical finding and symptoms, you must rule out severe AS.
Aortic Stenosis • Patients with the physical findings of AS should undergo selected laboratory examinations, including an ECG, a chest x-ray, and an echocardiogram. • The 2-D echocardiogram is valuable for confirming the presence of aortic valve disease and determining left ventricular (LV) size and function, degree of hypertrophy, and presence of other associated valve disease.
EKG • Usually shows NSR with LVH • Note: If AF is present, concomitant mitral valve disease or thyroid dz must be suspected.
Recommendations for Echocardiography in AS • Class 1 • Diagnosis and assessment of severity of AS. • Assessment of LV size, function, and/or hemodynamics. • Reevaluation of patients with known AS with changing symptoms or signs. • Assessment of changes in hemodynamic severity and ventricular compensation in patients with known AS during pregnancy. • Reevaluation of asymptomatic patients with severe AS. • Class IIa • Reevaluation of asymptomatic patients with mild to moderate AS and evidence of LV dysfunction or hypertrophy. • Class III • Routine reevaluation of asymptomatic adult patients with mild AS having stable physical signs and normal LV size and function.
ECHO • Modified Bernoulli equation (P=4v2) used to calculate gradient. • A maximal instantaneous and mean AV gradient is derived from the continuous-wave Doppler velocity across the aortic valve. • AVA can be estimated by continuity equation: • AVA=LVOTarea LVOTTVI AVTVI
ECHO/Doppler Pit Falls • Will underestimate AS if Doppler beam is not parallel to AS velocity jet. • Will rarely over-estimate mean gradient • Severe anemia (hemoglobin <8.0 g/dl) • Small aortic root • Sequential stenoses in parallel (coexistent LVOT and valvular obstruction)
Cath data • “Pull back” tracing can be used in pt with NSR but not accurate in irregular rhythms or low-out put states. • In low cardiac output, the stenosis may be severe, with a mean gradient <50mm Hg per echo. • Gorlin equation can be used to calculate AVA from pressure gradients, independent of CO. • AVA= (1000)(CO) (44)(SEP)(HR)(√P)
Hakke formula • Simple way to do things! • Used to calculate AV area • AVA=CO/(p-p gradient)
Treatment • AVR is clearly indicated in symptomatic patients. • Management decisions are more controversial in asymptomatic patients. • Patients with severe AS, with or without symptoms, who are undergoing CABG should undergo AVR at the time of revascularization. • There is general consensus that patients with moderate AS (e.g., mean pressure gradient ≥30 mm Hg) should undergo AVR at the time of CABG, but controversy persists regarding the indications for concomitant AVR at the time of CABG in patients with milder forms of AS.
Treatment Key Points • Aortic valve replacement is indicated for patients with symptoms of severe AS, regardless of the LV ejection fraction. • Coronary angiography may not be required preoperatively in younger patients without risk factors for CAD. • Percutaneous aortic balloon valvuloplasy is reserved only for critically ill patients as a “bridge” to surgery.
Asymptomatic patients with Severe AS • “The most common cause of death in patients with severe aortic stenosis is an operation” The prevailing notion. • Surgery should be performed at the onset of symptoms or LV systolic dysfunction.
AS w/ low output/low gradient • Exercise testing maybe performed to document exercise tolerance and hemodynamic response in pts with low CO.
Question • 55yo presents with DOE for past 6 months which is worsening. Pt has no significant PMH. PE: carotid upstroke 2+ delay but full volume, Second heart sound is single. There is a 3/6 SEM at RSB with mid-peak which ends at second heart sound. Echo: mild LVH, EF 65%, AV calcified and restricted. LVOT diameter is 2.0cm. Peak AV velocity is 2.5 m/sec with mean gradient of 18mm HG. LVOT velocity is 1.0 m/sec. • What is the AVA? A. 0.5 cm2 B. 0.8 cm2 C. 1.0 cm2 D. 1.2 cm2
Answer • AVA can be estimated by continuity equation: • LVOT diameter is 2.0cm. Peak AV velocity is 2.5 m/sec with mean gradient of 18mm HG. LVOT velocity is 1.0 m/sec. • The first step is to calculate the cross-sectional area of LVOT, as follows: CSA (LVOT) = π r2 = π(d/2)2. CSA (LVOT) = π r2 = π(d/2)2 = π(2/2)2 = π(1)2 = π • The formula for calculated aortic valve area (AVA) is:AVA (cm2) = CSA (LVOT) x (Vmax LVOT) ÷ Vmax AoV. • In this case, AVA = π cm2 x (1.0 m/sec ÷ 2.5 m/sec) = 3.14 cm2 x (0.4 m/sec) = 1.2 cm2
Question • What is the most likely etiology of this patient valve disease? A. Bicuspid. B. Inflammatory process. C. degenerative calcific disease. D. Congenital unicuspid valve.
Question • What is the most likely etiology of this patient valve disease? A. Bicuspid. B. Inflammatory process. C. degenerative calcific disease. D. Congenital unicuspid valve.
Question • What is the next step in the management of this patient? A. Dobutamine Echo. B. Medical treatment. C. Medical treatment but repeat study in 6 months. D. R/L heart cath with CO, AV gradient and coronary angio. E. Coronary angiogram and AVR.
Answer • What is the next step in the management of this patient? • A. Dobutamine Echo- only for Low CO pt with EF 65% • B. Medical treatment-pt with symptoms, • C. Medical treatment but repeat study in 6 months. • D. R/L heart cath with CO, AV gradient and coronary angio. Gives you more info • E. Coronary angiogram and AVR- AVA 1.2 per echo need more info before AVR
Question • Cardiac Cath: Aortic pressure 130/70 mmHg. LV pressure 180/15 mmHg. CO via thermo-dilutioon is 3.5 L/min. SEF is 280 ms at HR of 70bpm. Oxygen consumption is 270 cc/min. Pulmonary artery saturation is 64% and femoral artery saturation is 98%. Coronary arteries are normal • What is the calculated AVA? A. 0.5 cm2 B. 0.8 cm2 C. 1.0 cm2 D. 1.2 cm2
Answer • Cardiac Cath: Aortic pressure 130/70 mmHg. LV pressure 180/15 mmHg. CO via thermo-dilutioon is 3.5 L/min. • What is the calculated AVA? A. 0.5 cm2 B. 0.8 cm2 C. 1.0 cm2 D. 1.2 cm2 • Use Hakke formula • AVA=CO/(p-p gradient) • AVA=3.5 /(180-130) • 3.5/7= 0.5 cm2
Question • What is the next step in the management of this patient? • A. Medical therapy • B. AVR- homograft • C. AVR- mechanical • D. AVR - Ross procedure
Answer • What is the next step in the management of this patient? • A. Medical therapy • B. AVR- homograft • C. AVR- mechanical • D. AVR - Ross procedure • Less then 65yo without CI Mechanical valve TOC.
Question • The calculated aortic valve area using LVOT diameter = 2cm, Vmax AV = 4 m/sec, and Vmax LVOT = 0.8 m/sec is: A. 0.6cm². B. 1.0cm². C. 2.0cm². D. 1.2cm². E. 1.5cm².
Answer • The correct answer is A.The first step is to calculate the cross-sectional area of LVOT, as follows: CSA (LVOT) = π r2 = π(d/2)2. The formula for calculated aortic valve area (AVA) is:AVA (cm2) = CSA (LVOT) x (Vmax LVOT) ÷ Vmax AoV. In this case, AVA = π cm2 x (0.8 m/sec ÷ 4 m/sec) = (3.14)(0.2)= 0.6cm2
Question • A 50-year-old man is referred with amurmur of aortic stenosis--an incidental finding on a routine physical examination. The patient denies cardiac symptoms. The physical examination was unremarkable except for a grade IV/ VI late crescendo murmur typical of aortic stenosis and an S4 gallop. The resting ECG showed minimal ST and T changes but no voltage criteria for LVH. The Doppler echocardiogram showed a mean gradient of 60 mmHg with thickening of the ventricular walls but a normal ejection fraction. The patient underwent a Bruce protocol exercise test and quit after 5 minutes because of dyspnea. The thallium image showed no localized defect.
Question • What is the most appropriate management strategy at this time? A. Follow the patient with echocardiography every 6 months. B. Perform a dobutamine stress echo. C. Start enalapril. D. Follow the patient with an exercise stress test every 6 months. E. Recommend aortic valve replacement.
Answer • The correct answer is E. • This patient has severe aortic stenosis. Although the patient claims to be asymptomatic, his poor performance on the exercise test indicates he is not. In fact, patients with "asymptomatic" aortic stenosis have a 2-4% risk of cardiac death. Usually, however, symptoms develop 1-3 months before death. • In view of the low surgical risk and good long-term result of mechanical prosthetic valves, plus the definite incidence of sudden death in symptomatic patients who are not operated upon, the prudent course is to recommend aortic valve replacement. • This patient has a low risk of associated coronary artery disease, but this would need to be evaluated by catheterization preoperatively