B P8 C73 Aortic Regurgitation Flashcards
_____________________ can result from primary disease of the aortic valve leaflets and/or dilation of the aortic root and ascending aorta
Aortic regurgitation (AR)
Among patients with isolated AR who undergo aortic valve replacement (AVR), the percentage with primary disease of the aorta has been increasing steadily during the past few decades; it now represents the most common cause, accounting for more than 50% of all such patients in some series.
There are two predominant groups of patients who present with AR caused by a primary valve abnormality that is at least moderately severe.
(1) Young adults with noncalcified bicuspid aortic valves (BAVs) age 20 through 40 with AR caused by incomplete closure and/or prolapse of a valve leaflet.
(2) Patients age 60 or older with calcific aortic valve disease
In _____ aortic valve disease, fusion of the commissures and fibrotic retraction of leaflet tissue lead to a fixed orifice with a central defect often producing combined AS and AR
Rheumatic
AR secondary to _____ is now more common than primary valve disease in patients undergoing AVR for isolated AR.
Marked dilation of the ascending aorta
Patients with severe chronic AR, left unchecked, can develop the largest LV end-diastolic volumes of any form of heart disease, resulting in so-called _______________
Cor bovinum
During exercise, _____ declines and, with an increase in heart rate, diastole shortens and the regurgitation per beat decreases, facilitating an increment in effective (forward) cardiac output without substantial increases in end-diastolic volume and pressure.
Peripheral vascular resistance
Because the major portion of coronary blood flow occurs during diastole, when aortic pressure is lower than normal in AR, coronary perfusion pressure is _____.
Reduced
LV dilation also increases the LV systolic tension required to develop any level of systolic pressure.
Thus in AR, there is an increase in both preload and afterload. LV systolic function is maintained through the combination of chamber dilation and hypertrophy.
This leads to ________________, with replication of sarcomeres in series and elongation of myocytes and myocardial fibers
Eccentric hypertrophy
As AR persists and increases in severity over time, however, wall thickening fails to keep pace with the hemodynamic load, and end-systolic wall stress rises. At this point, the ____________________ results in a decline in systolic function, and the LVEF fall
Afterload mismatch
The principal manifestations, including exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea, usually develop gradually.
_____ is prominent late in the course; nocturnal angina may be troublesome and often is accompanied by diaphoresis, which occurs when the heart rate slows and arterial diastolic pressure falls to extremely low levels.
Angina pectoris
_____ are particularly distressing because of the great heave of the volume-loaded left ventricle during the postextrasystolic beat.
Premature ventricular contractions
In patients with chronic, severe AR, the head may bob with each heartbeat (_____ sign), and water hammer pulses, with abrupt distention and quick collapse (_____ pulse), are evident
de Musset sign
Corrigan pulse
The arterial pulse often is prominent and can be best appreciated by palpation of the radial artery with the patient’s arm elevated. A _____ pulse may be present and is more readily recognized in the brachial and femoral arteries than in the carotid arteries
Bisferiens
The _____ sign (also known as pistol shot sounds) refers to booming systolic and diastolic sounds heard over the femoral artery
Traube sign
The _____ sign consists of systolic pulsations of the uvula
Müller sign
The _____ sign consists of a systolic murmur heard over the femoral artery when it is compressed proximally and a diastolic murmur when it is compressed distally
Duroziez sign
Capillary pulsations can be detected by transmitting a light through the patient’s fingertips or exerting gentle pressure on the tip of a fingernail.
Quicke sign
The _____ in diastolic pressure reflects severity of AR and has prognostic implications.
Reduction
Korotkoff sounds often persist to zero even though the intra-arterial pressure rarely falls below 30 mm Hg.
The point of change in Korotkoff sounds (i.e., the muffling of these sounds in phase ____) correlates with the diastolic pressure
Phase IV
The apical impulse is _____ and is displaced _____.
Diffuse and hyperdynamic
Laterally and inferiorly
The diastolic murmur, the principal physical finding in AR, is of high frequency and begins immediately after A2.
It may be distinguished from the murmur of pulmonic regurgitation by its _____ onset and usually by the presence of a _____.
Earlier onset (i.e., immediately after A2 rather than after P2)
Widened pulse pressure
The murmur is heard best with the _____ of the stethoscope while the patient is sitting up and leaning forward, with the breath held in deep exhalation.
Diaphragm
In severe AR, the murmur reaches an early peak and then shows a dominant decrescendo pattern throughout diastole.
The severity of AR correlates better with the _____ of the murmur
Duration than with the intensity
In mild AR, the murmur may be limited to _____ diastole and typically is _____ pitched and blowing
MILD AR:
Early diastole
High pitched and blowing
In severe AR, the murmur is _____ and may have a rough quality.
When the murmur is musical (cooing dove murmur), it usually signifies _____ of an aortic cusp.
SEVERE AR:
Holodiastolic
Eversion or perforation of aortic cusp (musical, cooing dove murmur)
When AR is caused by primary valvular disease, the diastolic murmur is heard best along the _____.
However, when it is caused mainly by dilation of the ascending aorta, the murmur often is more readily audible along the _____.
Primary: left sternal border in the 3rd and 4th ICS
Dilation of Ascending Aorta: Right sternal border
Many patients with chronic AR have a harsh systolic outflow murmur caused by the increased total LV stroke volume and ejection rate, which often radiates to the _____.
Carotid vessels
- The systolic murmur often is more readily audible than the diastolic murmur
- Palpation of the carotid pulses will elucidate the cause of the systolic murmur and differentiate it from the mur- mur of AS.
A _____ correlates with an increased LV end- diastolic volume.
Its development may be a sign of impaired LV function, which is useful in identifying patients with severe AR who are can- didates for surgical treatment
S3
A mid-diastolic and late diastolic apical rumble, the _____ murmur, is common in severe AR and may occur in the presence of a normal mitral valve.
Austin Flint murmur
This murmur appears to be created by severe AR impinging on the anterior leaflet of the mitral valve or the free LV wall; convincing evidence for obstruction to mitral inflow in these patients is lacking.
Stage A Chronic AR
At risk
Anatomy:
Bicuspid aortic valve (or other congenital valve anomaly)
Aortic valve sclerosis
Diseases of the aortic sinuses or ascending aorta
History of rheumatic fever or known rheumatic heart disease
IE
Valve Hemodynamics:
AR severity none or trace
Hemodynamic consequences:
NONE
Symptoms:
NONE
Stage B Chronic AR
Progressive AR
Valve Anatomy:
Mild to moderate calcification of a trileaflet valve or bicuspid aortic valve (or other congenital valve anomaly)
Dilated aortic sinuses
Rheumatic valve changes
Previous IE
Valve Hemodynamics:
Mild AR:
Jet width <25% of LVOT
Vena contracta <0.3 cm
RVol <30 mL/beat
RF <30%
ERO <0.10 cm2
Angiography grade 1+
Moderate AR:
Jet width 25%-64% of LVOT
Vena contracta 0.3-0.6 cm
RVol 30-59 mL/beat
RF 30%-49%
ERO 0.10-0.29 cm2
Angiography grade 2+
Hemodynamic Consequences:
Normal LV systolic function
Normal LV volume or mild LV dilation
Symptoms:
NONE
Stage C Chronic AR
Asymptomatic severe AR
Valve Anatomy:
Calcific aortic valve disease
Bicuspid valve (or other congenital abnormality)
Dilated aortic sinuses or ascending aorta
Rheumatic valve changes
IE with abnormal leaflet closure or perforation
Valve Hemodynamics:
Severe AR:
Jet width 65% of LVOT
Vena contracta >0.6cm
Holodiastolic flow reversal in proximal abdominal aorta
RVol 60mL/beat
RF 50%
ERO 0.3cm2
Angiography grade 3+ to 4+
In addition, diagnosis of chronic severe AR requires evidence of LV dilation
Hemodynamic Consequences:
C1: Normal LVEF (>55%) and mild to moderate LV dilation (LVESD </=50 mm)
C2: Abnormal LV systolic function with depressed LVEF (</=55%)
or severe LV dilation (LVESD >50 mm or indexed LVESD >25 mm/m2)
Symptoms:
None; exercise testing is reasonable to confirm symptom status
Stage D Chronic AR
Symptomatic severe AR
Valve Anatomy:
Calcific valve disease
Bicuspid valve (or other congenital abnormality)
Dilated aortic sinuses or ascending aorta
Rheumatic valve changes
Previous IE with abnormal leaflet closure or perforation
Valve Hemodynamics:
Severe AR: Doppler jet width 65% of LVOT
Vena contracta >0.6 cm
Holodiastolic flow reversal in the proximal abdominal aorta
RVol 60 mL/beat
RF 50%
ERO 0.3 cm2
Angiography grade 3+ to 4+
In addition, diagnosis of chronic severe AR requires evidence of LV dilation
Hemodynamic Consequences:
Symptomatic severe AR may occur with normal systolic function (LVEF >55%), mild to moderate LV dysfunction (LVEF 40% to 55%), or severe LV dysfunction (LVEF <40%).
Moderate to severe LV dilation is present
Symptoms:
Exertional dyspnea or angina, or more severe HF symptoms
For angiographic assessment of AR, contrast material should be injected _____ into the aortic root, and filming should be carried out in the right and left anterior oblique projections
Rapidly (i.e., at 55 to 60 mL at 20 mL/sec/sec)
Patients with mild or moderate AR who are asymptomatic with normal or only minimally increased cardiac size require no therapy but should be followed clinically and by echocardiography every _____ months.
12 or 24 months
Asymptomatic patients with chronic severe AR and normal LV systolic function should be examined at intervals of approximately _____ months
6 months
The average rate of developing symptoms or LV systolic dysfunction in these latter series was less than ___% per year
6%
Numerous surgical series over the past two decades have indicated that _____ is among the most important determinants of mortality after AVR, particularly as LV dysfunction may become irreversible and not improve after AVR
Depressed LVEF
LV dysfunction is more likely to be reversible if detected early, before EF becomes severely depressed, before the left ventricle becomes markedly dilated, and before significant symptoms develop. It is, therefore, important to intervene surgically before these changes have become irreversible
_____ are the most important predictors of clinical course in asymptomatic patients
Measures of LV systolic volume and systolic function
Data compiled in the presurgical era indicate that without surgical treatment, death usually occurred within ___ years after the development of angina pectoris and within ___ years after the onset of heart failure. Even in the current era, 4-year survival without surgery in patients with New York Heart Association (NYHA) class III or IV symptoms is only approximately _____%
Angina: 4 years
HF: 2 years
30%
Class I indications for AVR in patients with AR
- In symptomatic patients with severe AR (stage D), aortic valve surgery is indicated regardless of LV systolic function (IB)
- In asymptomatic patients with chronic severe AR and LV systolic dysfunction (LVEF </=55%) (stage C2), aortic valve surgery is indicated if no other cause for systolic dysfunction is identified (IB)
- In patients with severe AR (stage C or D) who are undergoing cardiac surgery for other indications, aortic valve surgery is indicated (IC)
Although there is no specific therapy to improve clinical outcomes in patients with chronic AR, it is recommended to treat hypertension (systolic blood pressure [SBP] >_____ mm Hg), coronary artery disease (CAD), atrial arrhythmias, and any other cardiovascular comorbidities according to established guideline
> 140 mm Hg
No specific therapy to prevent disease progression in chronic AR is currently available (T/F)
True
Acute AR is caused most commonly by _____.
IE
Aortic dissection
Trauma
For symptomatic patients. chronic medical therapy may be necessary for some patients who refuse surgery or are considered to have a prohibitive risk of surgery because of comorbid conditions. These patients should receive an aggressive evidence-based heart failure regimen with ______.
ACE inhibitors (and perhaps other vasodilators)
Diuretics
Salt restriction
Beta blockers may also be beneficial
The characteristic features of acute AR are _____.
Tachycardia
Increase in LVDP
In contrast with the pathophysiologic events in chronic AR just described, in which the left ventricle can adapt over time to the increased hemodynamic load, in acute AR the regurgitant volume fills a ventricle of normal size that cannot accommodate the combined _____.
Large regurgitant volume and inflow from the left atrium
Because the ability of total stroke volume to rise acutely is limited in acute AR, forward stroke volume declines. The sudden increase in LV filling causes the LV diastolic pressure to rise rapidly above left atrial pressure during early diastole, causing the mitral valve to _____ in diastole.
Close prematurely
The ______ may compensate for the reduced forward stroke volume, and the LV and aortic systolic pressures may exhibit little change. However, acute severe AR may cause profound hypotension and cardiogenic shock.
Tahycardia
In light of the limited ability of the left ventricle to tolerate acute severe AR, patients with this valvular lesion often develop clinical manifestations of sudden cardiovascular collapse, including weakness, severe dyspnea, and profound hypotension secondary to the _____ stroke volume and _____ left atrial pressure
Reduced SV
Elevated LAP
Patients with _____ AR characteristically appear gravely ill, with tachycardia, severe peripheral vasoconstriction, cyanosis, and sometimes pulmonary congestion and edema
Acute severe
In acute AR, the LV impulse is _____, and the rocking motion of the chest characteristic of chronic AR is not apparent
Normal or almost normal
In acute AR, S1 may be_____ because of premature closure of the mitral valve, and the sound of mitral valve closure in mid- or late diastole occasionally is audible
Soft or absent
Closure of the mitral valve may be incomplete, however, and diastolic MR may occur.
The early diastolic murmur of acute AR is _____ pitched and of _____ duration compared with that of chronic AR, because as LV diastolic pressure rises, the (reverse) pressure gradient between the aorta and left ventricle is rapidly reduced
Lower pitched and shorter duration
A systolic murmur is common, resulting in to-and-fro sounds.
The Austin Flint murmur often is present but is of brief duration and ceases when LV pressure exceeds left atrial pressure in diastole.
With premature diastolic closure of the mitral valve, the presystolic portion of the Austin Flint murmur is eliminated.
In acute AR, the echocardiogram reveals a dense, diastolic Doppler signal with a _____ diastolic half time and an end-diastolic velocity approaching zero
Short
In acute AR, the ECG will usually show _____.
If endocarditis is a possible etiology, progressive severity of heart block on serial ECGs may indicate the presence and expansion of an accompanying _____.
Sinus tachycardia
Aortic root abscess
In acute AR, radiographic examination often reveals evidence of _____.
Marked pulmonary edema
Because early death caused by LV failure is frequent in patients with acute severe AR, prompt _____ is indicated.
Surgical intervention
Even a normal ventricle cannot sustain the burden of acute, severe volume overload. Therefore the risk of acute AR is much greater than that of chronic AR.
While the patient with acute AR is being prepared for surgery, treatment with an IV _____ often is necessary.
IV positive inotropic agent (dopamine or dobutamine) and/or a vasodilator (nitroprusside)
______ are contraindicated, because either lowering the heart rate or augmenting peripheral resistance during diastole can lead to rapid hemodynamic decompensation.
Beta blockers and IABP
In hemodynamically stable patients with acute AR secondary to active infective endocarditis, operation may be deferred to allow _____ days of intensive antibiotic therapy.
5-7 days
However, AVR should be undertaken at the earliest sign of hemodynamic instability or if there is any evidence of abscess formation. If an acute aortic dissection is the cause for the AR, the aorta will also need to be fixed during surgery.
Echocardiography is essential in evaluating cause and severity of AR as it impacts LV volume and function. Anatomic findings such a BAV, thickening of the valve cusps, other congenital abnormalities, prolapse of the valve, a flail leaflet, or vegetation are usually well delineated; the size and shape of the aortic root can be evaluated
Recent studies have suggested that ______, indexed to body surface area, is a strong predictor of adverse clinical outcomes. 1
LVESV
The most sensitive and accurate noninvasive techniques for the diagnosis and evaluation of AR.
As the severity of AR increases, there will be a larger area of turbulence in the LV outflow tract on color flow imaging, but this is only a semi-qualitative measure.
Doppler echocardiography and color flow Doppler imaging
There are indirect Doppler findings in severe AR including a
High LV outflow velocity
Reversal of flow in the descending aorta
Short diastolic half-time of the AR
This is the most accurate noninvasive technique for assessing LVESV, end-diastolic volume, and mass and is recommended when echocardiographic evaluation of LV size and function or severity of regurgitation is suboptimal.
CMR
In patients for AVR, higher long-term postoperative risk in patients undergoing surgery with LVEF below ____
55%
Therefore it is highly desirable to operate on patients before irreversible LV changes have occurred, and surgery is indicated for patients with ______
Severe chronic AR and any symptoms
Surgery should not be withheld in symptomatic patients with even moderate to severe LV systolic dysfunction, as outcomes are _____ than with medical therapy, and there is always the possibility of improvement in LV function following surgery with the addition of guideline-directed medical therapy
Better with surgery
In the absence of obvious c indications or serious comorbidity, surgical treatment is advisable for asymptomatic patients with chronic severe AR with either an ______ or a severe increase in LVESD (defined as ________),
LVEF of 55% or less
LV end-systolic diameter [ESD] greater than 50 mm or indexed LVESD greater than 25 mm/m2
Operative correction should be deferred in patients with chronic severe AR whic include
Asymptomatic
Exhibit good exercise tolerance
LVEF greater than 55% without severe LV dilation as defined previously or progressive LV dilation on serial echocardiograms
_____ is valuable in predicting outcome in asymptomatic patients.
LVESD
True or False
The indications for AVR for patients with chronic severe AR secondary to aortic sinus or ascending aortic disease are similar to those for patients with primary valvular disease
True
In patients undergoing AVR for severe AR, concomitant surgery to repair the aortic sinuses or replace the ascending aorta is indicated if the amount of aortic dilation is ____
Greater than 45 mm
