Aortic_Regurgitation_8fc642f0-ebf6-4ae4-bf66-419d7a8bbb7e.pptx, management

Aortic regurgitation

1. Aortic Regurgitation Kush Raut - PGY II Internal Medicine ,NMCTH – 17 Jan 2024

2. Overview Introduction Types Etiology Epidemiology Pathophysiology Clinical Features Progression and Natural History Diagnosis Staging Monitoring Treatment

3. Introduction Aortic regurgitation (AR) is characterized by incompetence of aortic valve that causes blood to flow in reverse direction from the aorta to the LV during ventricular diastole It imposes a combined volume and pressure overload on the LV Clinical presentation is highly variable and depends on multiple factors, including acuity of onset, aortic and LV compliance, hemodynamic conditions, and severity of the lesion.

4. Types Acute AR and Chronic AR are two types recognized on the basis of onset The acute onset AR is usually a medical emergency due to the inability of the left ventricle to quickly adapt to the rapid increase in end-diastolic volume caused by regurgitant blood. If not surgically corrected, acute severe AR commonly results in cardiogenic shock. In chronic AR, the clinical symptoms appear relatively late since the gradually dilating left ventricle and compensatory mechanisms dampen many of the hemodynamic abnormalities resulting from chronically increased diastolic volumes 

5. Epidemiology The prevalence of aortic regurgitation increases with age Severe AR is clinically more often observed in men than in women The Framingham Offspring Study revealed the prevalence of AR as 13% in men and in 8.5% in women Prevalence of moderate or greater severity was 0.5% and 2.7%, respectively The Strong Heart Study revealed 10% prevalence of AR in a Native American population Presentation Second or third decade of life – Rheumatic Heart Disease Fourth to sixth decades – Degenerative or congenital causes

6. Etiology AR results from the malcoaptation of the aortic leaflets due to the abnormalities of the aortic leaflets (Valvular disease) or their supporting structures - aortic root and annulus, (Aortic Root disease) or both

7. Etiology – Valvular Disease Rheumatic Heart Disease Most common Valvular cause of AR in developing countries Infiltration of cusps with fibrous tissues preventing cusp apposition during diastole Diffusely thickened mitral valve also present with or without calcification Fusion of commissure may or may not be present Usually leads to regurgitation into the left ventricle through a defect in the center of the valve

8. Etiology – Valvular Disease Bicuspid aortic valve Can be associated with aortic root dilation as well Commonly results in stenosis in adults Can also result in incomplete closure and/or prolapse leading to isolated AR or As/AR combination

9. Etiology – Valvular Disease Atherosclerotic degeneration Most common cause of AR in western world Focal fibrous thickening of cusps Calcific deposits

10. Etiology – Valvular Disease Infective endocarditis The infection may destroy or cause perforation of a leaflet The vegetations may interfere with proper coaptation of the cusps Tear of the ascending aorta and resulting loss of commissural support can cause prolapse of an aortic cusp.

11. Etiology – Valvular Disease Other Valvular causes As a complication of percutaneous aortic balloon valvotomy Myxomatous proliferation of aortic valve Various congenital causes - unicommissural and quadricuspid valves, rupture of a congenitally fenestrated valve In association with SLE, RA etc

12. Etiology – Aortic Root Disease Idiopathic aortic root dilation Aortoannular ectasia Marfan syndrome Ehlers- Danlos syndrome Osteogenesis imperfecta Aortic dissection Syphilitic aortitis Trauma Ankylosing spondylitis Bicuspid aortic valve with dilated aortic root

13. Etiology – Acute AR Endocarditis – valve destruction, leaflet perforation, rupture of aortic perivalvular abscess into the left ventricle Aortic dissection – dilation of the sinuses with incomplete coaptation of the leaflets at the center of the valve, involvement of a valve commissure resulting in inadequate leaflet support, direct extension of the dissection into the base of a leaflet resulting in a flail valve leaflet and prolapse of the dissection flap across the aortic valve into the left ventricular outflow tract in diastole impeding leaflet closure Rupture of a congenitally fenestrated cusp Traumatic rupture of the valve leaflets – deceleration injury or blunt trauma to the chest Iatrogenic – Complication of procedures such as aortic balloon valvotomy or transcatheter aortic valve replacement (TAVR) Prosthetic valve dysfunction

14. Pathophysiology Chronic AR imposes both volume and pressure overload on the LV The volume overload is a consequence of the regurgitant volume The pressure overload is due to increased total stroke volume because both the regurgitant volume and the forward stroke volume are ejected into the aorta during systole In early compensated severe AR, the LV adapts to the volume overload by eccentric hypertrophy, in which sarcomeres are laid down in series and myofibers are elongated Eccentric hypertrophy preserves LV diastolic compliance, such that LV filling pressures remain normal despite a large regurgitant volume It also increases LV mass, such that the LV volume/mass ratio is normal, and LV ejection fraction (LVEF) is maintained by increased preload

15. Pathophysiology Over time, progressive LV dilation and systolic hypertension increase wall stress that leads to overt LV systolic dysfunction, manifested by a decline in LVEF In decompensated severe AR, LV systolic dysfunction is accompanied by decreased LV diastolic compliance as a result of hypertrophy and fibrosis, leading to high filling pressures and heart failure symptoms Exertional dyspnea is the most common manifestation, but angina can also occur because of a reduction in coronary flow reserve with predominantly systolic coronary flow In experimental animals, the transition from a compliant (chronic compensated AR) to a stiff (decompensated AR) LV chamber appears to involve upregulation of several cardiac fibroblast genes

16. Pathophysiology

17. Pathophysiology – Acute AR The regurgitant volume fills a small ventricle that has not had time to dilate Results in an acute increase in left ventricular diastolic pressure and a fall in forward cardiac output The decline in forward stroke volume may be exacerbated by Shortening of diastolic filling time due to early closure of the mitral valve (due to high end diastolic pressures) Tachycardia (due to decrease in forward flow and cardiac output) The net effect is often profound hypotension and cardiogenic shock The elevated left ventricular end-diastolic pressure leads to elevated left atrial and pulmonary venous pressures, which can lead to pulmonary edema

18. Clinical Features - Symptoms Patients with AR may remain asymptomatic for decades, even if there is progressive ventricular dilation Symptoms include exertional dyspnea, angina, and other symptoms of heart failure Exertional dyspnea develops in some patients with severe AR, particularly in patients who have developed left ventricular systolic dysfunction More severe heart failure symptoms such as orthopnea, paroxysmal nocturnal dyspnea and pulmonary edema may develop without appropriate treatment Exertional angina can occur even in the absence of underlying coronary artery disease, though the coronary arteries are typically large. Angina is caused by reduced coronary flow reserve as epicardial coronary flow shifts from predominantly diastolic to predominantly systolic

19. Clinical Features - Signs Arterial pulse and related findings Collapsing pulse or water hammer pulse - noted in the radial artery with upper limb lifted up passively and felt by the palm of the hand Bisferiens pulse - two peaks in each systole Corrigan’s sign/dancing carotid – Prominent carotid 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/murmur - A stethoscope kept over the femoral artery picks up a systolic murmur with proximal compression and diastolic murmur with distal compression. The diastolic murmur is specific Becker’s sign – visible pulsations of retinal arteries

20. Clinical Features – Signs Lighthouse sign - blanching and flushing of forehead Landolfi's sign - alternating constriction and dilatation of pupil Locomotor brachii - a prominent pulsation of brachial artery 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 Quincke's sign - pulsation of the capillary bed in the nail

21. Clinical Features – Signs On precordial inspection and palpation, the combination of left ventricular enlargement and forceful systolic function results in the apical impulse being displaced laterally and inferiorly and being diffuse and hyperdynamic On auscultation, S1 is normal (may be soft - long PR interval) S2 is variable; it may be soft, absent, or single A2 is often soft or absent while P2 may be normal, but obscured by the diastolic murmur A third heart sound (S3 gallop) is heard when left ventricular function is severely depressed

22. Clinical Features – Signs Murmurs: A high-frequency, decrescendo early diastolic murmur is typically heard over the 3 rd or 4 th intercostal space at the left sternal border best heard sitting up, leaning forward at end expiration In some patients, a mid and late diastolic apical rumble ( Austin-Flint murmur ) is heard, possibly because of vibration of the anterior mitral leaflet as it is struck by a posteriorly directed AR jet A systolic ejection murmur due to high ejection volumes is present in significant AR

23. Clinical Features – Acute AR Usually presents with sudden cardiovascular collapse and pulmonary edema. Other presenting symptoms are related to the cause of acute AR ( eg , endocarditis or aortic dissection) Physical examination — Manifestations of cardiogenic shock predominate like profound hypotension, pallor, diaphoresis, occasional cyanosis, and other signs of peripheral vasoconstriction as well as signs of pulmonary edema. The pulse pressure is normal or may be reduced, but the arterial pulse is usually weak, thready , and rapid. The cardiac apex is generally not displaced and is not hyperdynamic .

24. Clinical Features – Acute AR The pulse pressure is normal or may be reduced, but the arterial pulse is usually weak, thready , and rapid. The cardiac apex is generally not displaced and is not hyperdynamic . The peripheral manifestations of chronic AR, associated with an increased pulse pressure are less apparent or may be entirely absent with acute AR Auscultation – Soft S1 – due to early closure of the mitral valve The aortic component of S2 is often soft, while P2 is usually increased, reflecting pulmonary hypertension An S3 is frequently heard Murmur is a low pitched early diastolic murmur beginning after S2

25. Differences between Acute & Chronic AR Features Acute AR Chronic AR Onset Early, sudden Late, insidious Pulse pressure Near normal Wide Systolic pressure Normal or Increased decreased Diastolic pressure Normal or Markedly decreased decreased LV impulse May be normal and not hyperdynamic Hyperdynamic Auscultation     a. S1 Soft or absent Normal b. P2 Normal or increased Normal c. S3 Common Uncommon d. AR murmur Short, medium pitched Long, high pitched e. Aortic systolic murmur Grade 3 or less Grade 3 or more f. Austin-Flint murmur Not present May be present Peripheral arterial signs Absent Present ECG Normal LV LV enlargement Chest X-ray Normal to moderately increased LV Markedly increased LV

26. Progression and Natural History Progression of AR depends on a interaction of several variables – AR severity, Aortic root pathology, The adaptive response of the LV AR severity may worsen as a result of progressive leaflet pathology and/or further dilation of the aortic root In addition, LV dilation occurs gradually and progressively, depending on the severity of AR, hemodynamic factors, the degree of eccentric hypertrophy and remodeling, which may vary from patient to patient and may be related to genetic factors

27. Progression and Natural History Bonow et al studied 104 asymptomatic patients with severe AR and normal LVEF for 11 years The rate of attrition (defined as death, symptoms, or asymptomatic LV dysfunction) was <5%/y & rate of sudden death was 0.4%/y 58% of patients remained asymptomatic with normal LV systolic function Dujardin et al investigated 246 patients with moderately severe or severe AR with a mean follow-up time of 7 years The 10-year mortality rate was 34%, with independent predictors of survival being age, functional class, comorbidities, atrial fibrillation, LV end-systolic diameter, and ejection fraction (EF).

28. Progression and Natural History Asymptomatic patients with normal LV systolic function Progression to symptoms and/or LV dysfunction <6%/y Progression to asymptomatic LV dysfunction <3.5%/y Sudden death <0.2%/y Asymptomatic patients with LV systolic dysfunction Progression to symptoms >25%/y Symptomatic patients Mortality rate >10%/y

29. Progression and Natural History Asymptomatic patients with normal LV function generally have a favorable prognosis and indicate that Decline in LVEF with exercise or serial follow-up may identify patients who will require surgical intervention Even moderate symptoms or evidence of LV dilatation are at higher risk and should be considered for early intervention.

30. Diagnosis Chest X Ray Electrocardiogram Echocardiography Cardiovascular magnetic resonance Cardiac Catheterization

31. Diagnosis - Chest X Ray Not indicated for the diagnosis of AR but may be obtained in selected patients with AR such as those in whom the cause of dyspnea is uncertain Cardiomegaly - due to the dilation of the LV Prominent Left Ventricle Ascending Aortic dilatation LAE if severe LV dysfunction

32. Diagnosis - Electrocardiogram Not indicated for diagnosis of AR but is commonly included in the evaluation of patients with AR to exclude concurrent conditions ( eg , arrhythmia), and to establish a baseline for future comparison. Reflects the adaptive changes that occur in the left ventricle as a result of the volume overload, typically with findings for left ventricular hypertrophy (LVH). Conduction abnormalities can occur late in the course of AR when significant left ventricular dysfunction ( myopathic ventricle) occurs. Isolated atrial and ventricular premature beats are common.

33. Diagnosis - Echocardiography A transthoracic echocardiogram (TTE) is the key test in diagnosis and evaluation of AR A transesophageal echocardiogram (TEE) is indicated in selected patients with AR such as those with technically suboptimal TEE or endocarditis with non-diagnostic TTE Echocardiography provides an assessment of anatomy of the Aortic Root and Leaflets detection of the presence of AR (confirms the diagnosis of AR), establishes its severity, evaluates left ventricular size and function

34. Anatomy of the Aortic Root and Leaflets Dilated aortic root due to aortoannular ectasia Large, mobile vegetation in infective endocarditis Bicuspid aortic valve

35. Detection of the presence and severity of AR Assessed by Color flow Doppler Sensitivity > 95% & Specificity ~100% Color flow jets are composed of 3 distinct segments: The proximal flow convergence zone is the area of flow acceleration into the orifice, The vena contracta is the narrowest and highest velocity region of the jet at or just downstream from the orifice, The jet which occurs distal to the orifice in the LV cavity in the case of AR

36. Assessment of Severity A jet width/LVOT width <25% is specific for mild AR, whereas a jet width/LVOT width ratio >65% is specific for severe AR Vena Contracta Imaging The narrowest central flow region of a jet Measured in a parasternal long-axis or short-axis view in a color Doppler mode Vena contracta width of 6 mm - severe AR, with a sensitivity of 95% and a specificity of 90% & 3 mm is specific for mild AR Regurgitant volume Severe AR if ≥60 ml per beat Effective regurgitant orifice area Calculated by dividing the regurgitant volume by the velocity time integral of the AR jet obtained from continuous wave Doppler EROA of > 0.30 cm2 denotes severe AR

37. Diagnosis - Cardiovascular magnetic resonance Indicated in patients with moderate or severe AR with suboptimal or inconclusive echocardiographic assessment Quantifies AR severity, measures left ventricular diastolic and systolic volumes, and assesses left ventricular systolic function Aortic regurgitant volume and regurgitant orifice area can also be quantified by CMR No ionizing radiation or exogenous contrast is required

38. Diagnosis - Cardiac Catheterization Indicated when noninvasive tests are inconclusive or provide discrepant results from clinical findings Enables assessment of the following parameters A semi-quantitative assessment of the severity of AR Aortic valve movement and the number of leaflets Determination of left ventricular size, systolic function (ejection fraction), and pressures Aortic root dimension and associated disorders ( eg , dissection, sinus of Valsalva aneurysm) By invasive angiography, severe AR is diagnosed by the presence of 3+ to 4+ regurgitation and identification of a high regurgitant fraction.

39. Monitoring Should be monitored for changes in symptoms, severity of AR and left ventricular (LV) systolic dysfunction to reassess the stage of AR Serial monitoring of the severity of AR is generally performed by transthoracic echocardiogram, since physical findings are not reliable If the echocardiogram is inconclusive, cardiovascular magnetic resonance imaging is suggested. Cardiac catheterization is recommended if noninvasive tests are inconclusive or if there is a need to assess coronary anatomy prior to aortic valve surgery

40. Monitoring Clinical follow-up —At least yearly clinical evaluation including history and physical examination for key symptoms for staging of AR - symptoms of heart failure (and occasionally angina) Echocardiography Mainstay for serial monitoring and evaluation of patients with chronic AR For mild AR - every three to five years For moderate AR - every one to two years For severe AR - every 6 to 12 months; more frequently if the LV is dilating Also recommended if the patient becomes symptomatic or has equivocal symptoms or a decline in exercise tolerance

41. Treatment - Medical Therapy Medical therapy is not able to significantly reduce regurgitant volume in chronic severe AR because the regurgitant orifice area is relatively fixed and the diastolic blood pressure is already low.

42. Treatment - Endocarditis prophylaxis Antibiotic prophylaxis is not recommended when patients with native valve disease, including chronic AR, undergo dental or other invasive procedures that produce significant bacteremia with organisms associated with endocarditis. Antibiotic prophylaxis is recommended in certain high-risk settings like presence of a prosthetic heart valve or prior history of infective endocarditis.

43. Treatment - Surgery Mainstay of treatment of symptomatic severe AR and select patients with asymptomatic AR Predominantly performed – Aortic Valve Replacement Aortic valve repair is an option only at centers with established expertise and experience and for patients with suitable anatomy (aortic dilation without a thickened, deformed, or calcified valve) Aortic valve surgery is not recommended in a truly asymptomatic patient with severe AR with normal LV function (LVEF ≥50 percent and LV end-systolic dimension ≤50 mm) unless there is another indication for cardiac surgery

44. Post operative outcomes Surgery for symptomatic patients with severe AR reduces LV volumes, LV mass, wall stress and increases LVEF. If asymptomatic, surgery is ideally performed when LVEF 50-55%. Dilated LV or low LVEF pre-op can still benefit from surgery. Patients with markedly decreased LVEF should not be denied surgery – these patients generally have an improvement in LVEF post-op as a result of relief of high afterload, especially if LV dysfunction has lasted less than one year. It is almost never “too late” to operate in chronic, severe AR.

45. References Braunwald’s Heart Disease Harrison’s principle of Internal Medicine 2021 ESC/EACTS Guidelines for the management of valvular heart disease 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease

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