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AORTIC STENOSIS De-huis T.J. UFSBloemfontein. Aortic Stenosis  Introduction ~  Etiology:  Calcification ~ normal trileaflet aortic valve:  most common.

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Presentation on theme: "AORTIC STENOSIS De-huis T.J. UFSBloemfontein. Aortic Stenosis  Introduction ~  Etiology:  Calcification ~ normal trileaflet aortic valve:  most common."— Presentation transcript:

1 AORTIC STENOSIS De-huis T.J. UFSBloemfontein

2 Aortic Stenosis  Introduction ~  Etiology:  Calcification ~ normal trileaflet aortic valve:  most common cause in adults with normal trileaflet or  Congenital bicuspid valve  Pathophysiology similar to atherosclerosis, thus predisposing factors include ~  Age  Male gender  Hyperlipidaemia  Evidence of active inflammation

3 Aortic Stenosis  Etiology ~  Calcification:  Usually in 6 th to the 8 th decade of life  Mainly caused by solid calcific deposits in the cusps than commissural fusion  Calcification of congenital bicuspid aortic valve~  1-2% of babies are born with a bicuspid Ao valve  Mostly males  Contributes more to the total number of AS cases than the trileaflet  Develops earlier than in Tricuspid leaflet ~ about the 2 nd decade

4 Aortic Stenosis  Etiology ~  Congenital Aortic Stenosis :  Usually detected and treated early in childhood and adolescence  Usually a unicuspid unicommissural valve  Sudden dearth is common due to LV strain  Ejection fraction is usually supra normal with concentric ventricular hypertrophy

5 Aortic Stenosis  Etiology ~  Rheumatic Valve Disease :  Becoming rare in developed countries  Mitral valve almost always affected  Commissural fusion present

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7 Aortic Stenosis  Pathophysiology ~  Pathophysiology and relation to symptoms :

8 Aortic Stenosis  Pathophysiology ~  Pathophysiology and relation to symptoms  Asymptomatic patient have a good outlook even with severe stenosis, whereas  An individual with symptoms has a mortality rate of 25% per year  Pressure Overload Hypertrophy  Narrowing of valve orifice to half the normal diameter of 3 cm² causes little obstruction to LV- outflow tract with a small gradient across the valve Blase R Carabello Blase R Carabello

9 Aortic Stenosis

10  Pathophysiology ~  Pressure Overload Hypertrophy:  LV hypertrophy → a major compensatory mechanism, off setting the pressure overload  Pressure overload →  LV afterload → ↓ ejection performance  Afterload ~  wall stress σ = pr/2th ( Laplace Equation)  P ~ ventricular pressure  R ~ventricular radius  th ~ ventricular thickness Blase R Carabello

11 Aortic Stenosis  Pathophysiology ~  Pressure Overload Hypertrophy:  As the LV pressure  so does the thickness ( concentric hypertrophy) ~ thus keeping the afterload normal  Maintenance of normal afterload → normal EF and stroke volume  Note ~  Hypertrophy is a double edged sword, on the one hand maintaining normal EF and on the other impeding coronary artery blood flow reserve,  It reduces diastolic function and  Is associated with increased mortality Blase A Carabello

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13 Aortic Stenosis  Natural History ~  Severity of stenosis  with time  Average rate of decrease in Ao valve ~ 0.12 cm² per year  Progression is more in pts with degenerative disease than in congenital or rheumatic etiology  Survival  35% of unoperated with usual AS symptoms are alive at 10 yrs ~ Grant  Wood stated that 46% of such pts were alive at 1 to 7 yrs later  ACC/AHA guidelines ~ after onset of symptoms, average survival is < than 2 to 3 yrs

14 Aortic Stenosis  Survival ~

15 Aortic Stenosis  Natural History ~  Survival :  15% to 20% of all deaths in AS are sudden  VF  Acute pulmonary edema from sudden LV failure  Gradual cardiac failure after 5 yrs of diagnosis  A few patients may display signs of moderate pulmonary arterial hypertension and,  Others develop RV failure Kirklin/Barratt-Boyes Kirklin/Barratt-Boyes

16 Aortic Stenosis  Natural History ~  Survival:  Asymptomatic patients ~  ¼ develop symptoms within a year  ½ by 3 yrs and  ¾ by 4rs  Sudden death occurs in < 1% Otto and colleagues Otto and colleagues

17 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Asymptomatic  Symptomatic  Classic triad (in 1/3 of pts) ~  Angina pectoris  50% to 70% of pts  Common in pts with AS and CAD  In severe AS than pts with less severe disease  Syncope  30% to 50% of pts  Peripheral vasodilatation from faulty baroreceptor mechanisms  Pulmonary Venous Hypertension  30% to 40%  Dyspnea, orthpnea, PND, or frank pulmonary edema  Associated with  LVEDP and systolic wall stress, ↓ CO and EF

18 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  10% of patients survive typical symptoms long enough to develop secondary RV failure ~   right atrial and jugular pressure,  Hepatomegaly,  Cardiac cachexia  Tricuspid regurgitation (rarely)

19 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Physical examination  Auscultation ~  A crescendo-decrescendo systolic ejection murmur radiating to the neck From the collection of David Liff, MD, Emory University Hospital

20 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Physical examination  Auscultation ~  In mild disease  murmur peaks in early systole  S2 is physiologically split and  Carotid upstrokes are normal

21 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Physical examination  Auscultation ~  As the AS progress  The murmur becomes louder  Peaks progressively later in systole, and  Is associated with a thrill  With further worsening of stenosis  Murmur intensity becomes less due to ↓ in SV  The carotid upstrokes are diminished in volume and rate of rise is delayed ( parvus et tardus )  The apex beat is increased Blase A Carabello Blase A Carabello

22 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Special Investigations ~ LV hypertrophy

23 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Special Investigations ~  ECG ~  Non specific ST-wave and T wave abnormalities ~ V 6 lead – strain pattern)  Chest Radiography ~  Non specific  LV hypertrophy with boot shape  +/- calcification of Ao valve

24 Aortic Stenosis

25  Clinical Features and Diagnostic Criteria:  Echocardiography ~  Thickened and calcified Ao valve with dense cusp echoes throughout cardiac cycle  Decreased separation of leaflets in systole with reduced opening orifice ( mm mild, 8-12 mm moderate, and < 8 mm in severe)  +/- doming in systole  Dilated Ao root   thickness of LV wall (concentric LV hypertrophy)  Hyperdynamic contraction of LV (in compensated state)  ↓ mitral EF slope (↓ LV compliance)  LA enlarged   Ao gradient (Doppler)  ↓ Ao valve area (unreliable)

26 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Echocardiography ~

27 Fig 3 Continuous wave Doppler echocardiogram in patient with severe aortic stenosis (same patient as in figure 2). Ramaraj R, Sorrell V L BMJ 2008;336: ©2008 by British Medical Journal Publishing Group

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29 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Bernoulli equation ~

30 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Bernoulli equation ~ G=4V² G=4V²  G ~ gradient  V ~ peak transvalvular flow velocity

31 Aortic Stenosis

32  Measurement of Aortic Valve Area ~  Continuity equation  Gorlin equation  Hakki equation

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36 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Graded exercise testing ~  Not as risky in asymptomatic patients with AS  May help in deciding on operative intervention, or if continued observation is advised, recommendations concerning vocational, recreational, or sports participation  And is positive when ~  Symptoms occur  Inadequate blood pressure or drop in more than 10 mmHg or greater  Bradycardia  Arrhythmia  Conduction disturbances  ST-segment depression (0.2 mV or more) Kirklin/Barrat-Boyes

37 Aortic Stenosis

38  Clinical Features and Diagnostic Criteria:  Cardiac Catheterization ~  Done if pt > than 40 yrs to asses coronary arteries  If non invasive studies are inconclusive  Transvalvular gradient and correct cardiac out assessment are important ~ Gorlin equation to determine Ao valve area Kirklin/Barrat-Boyes Kirklin/Barrat-Boyes Blase A. Carabello Blase A. Carabello

39 Aortic Stenosis  Clinical Features and Diagnostic Criteria:  Cardiac Catheterization ~

40 Aortic Stenosis

41  Clinical Features and Diagnostic Criteria:  Biomarkers and Symptomatic Status ~  Brain Natriuretic Peptide (BNP)  A maker of hypertrophy and  Use of preload reserve to maintain compensation  Is high in AS with symptoms  ? Usefulness in asymptomatic patients  Renal failure, pulmonary hypertension and obesity interfere with the predictable value of BNP measurement Blase A. Carabello Blase A. Carabello

42 Aortic Stenosis  Treatment :  Medical Treatment ~  ?role of statins in progression of disease  Cowell and colleagues  Showed no benefit  Other retrospective studies  Showed benefit ~ ? Disease severity (Moura and colleagues) Blase A. Carabello Blase A. Carabello

43 Aortic Stenosis  Treatment:  Medical Treatment ~  Vasodilators  Generally contraindicated in AS  Hypotension and  Syncope  Except in concomitant hypertension and decompensated heart failure  ACE-I can be used  Sodium nitroprusside  ?  contractility ~ causes decrease ventricular filling pressure → increased myocardial blood flow → enhanced contractility Blase A. Carabello Blase A. Carabello

44 Aortic Stenosis  Treatment:  Surgical Treatment ~  Indications  Symptomatic patients with severe stenosis  Patients with moderate or severe stenosis having operation for coronary artery disease, other heart valve disease, or aortic disease  Asymptomatic patients with severe aortic stenosis  LV systolic dysfunction  Abnormal response to exercise (hypotension)  Ventricular tachycardia  Marked LV hypertrophy (≥15 mm)  Aortic valve area (<0.6 cm²) Kirklin/Barrat-Boyes

45 Aortic Stenosis  Treatment:  Surgical Treatment ~  Isolated Aortic Valve replacement:  Initial Steps ~  Usual preparations  Median sternotomy  CPB established at 34˚C, single two-staged venous cannula  Cardioplegia – antegrade +/- retrograde  Body is cooled down to 28˚C  Ascending Aorta is Cross clamped ~ promptly if ventricular fibrillation is allowed  +/- LV vent

46 Aortic Stenosis  Treatment:  Surgical Treatment ~

47 Aortic Stenosis  Treatment:  Surgical Treatment ~

48 Aortic Stenosis  Treatment:  Surgical Treatment ~

49 Aortic Stenosis  Treatment:  Surgical Treatment ~  Prosthetic Aortic Valve  Interrupted suture technique  Continuous suture technique  Allograft Aortic Valve  Subcoronary technique  Root enlargement technique

50 Nezic D. et al.; J Thorac Cardiovasc Surg 2008;135:1401-a-1402-a Surgical techniques of posterior aortic root enlargement reported so far (Nick's-white arrow, Nunez's-black arrow, Manouquian's-black plus black dotted arrows)

51 Aortic Stenosis  Special Features Of Postoperative Care:   Mechanical Prosthesis ~   Life long sodium warfarin (on the evening of the 2 nd postoperative day)   INR ~ around 2.5 (2-3)   If AF or  atrium or impaired LV function ~ INR 3.0 ( )   ? Addition of aspirin ~ benefits v/s hemorrhage   ?enoxaparin ~ 1mg.kgֿ¹ for five days until INR reaches therapeutic level

52 Aortic Stenosis  Special Features Of Postoperative Care:  Bioprostheses (human, porcine, bovine)   No need for anticoagulation   Aspirin can be used for 1 month if risk of thromboembolism is great (81 mg daily)   AF ~   if patients are still in AF 48 hrs after surgery, then warfarin is administered until sinus rhythm is restored

53 Aortic Stenosis  Special Features Of Postoperative Care:  Patients with LV hypertrophy ~   These require high LV filling pressures, thus   Mean LA pressure of > 10 mmHg (15 to 18 mmHg)   Sinus tachycardia ~   If heart rate is > 100 beats. min ֿ¹ for several days without returning to normal, then beta blockers can be started

54 Aortic Stenosis  Results:  Early (Hospital) Death ~  3.4% hospital mortality for primary isolated aortic valve replacement ( The Society of Thoracic Surgeons National Database)  Risk higher for females than males (3.9% versus 3.0%)  With CABG then STS National Database figures rise to 6.3%

55 Aortic Stenosis  Results:  Modes of Death ~  Early deaths   Acute cardiac failure   Neurologic complications   Hemorrhage and   Infection   Late deaths (20%)   Cardiac failure   Myocardial infarction   Thromboembolism

56 Aortic Stenosis  Results:   Incremental Risk Factors for Premature Death   Older age   ?Ethnicity ( African-Americans at increased risk)   Functional Status (NYHA)   LV morphology and Function   Ao regurgitation   Gender   Angina   AF Kirklin/Barrat-Boyes

57 Thank You


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