Acquired valve disease Flashcards
Color-flow Doppler is notoriously variable if technical factors are not set properly. The color jet area of any regurgitation is inversely proportional to…..
pulse repetition frequency (PRF and Nyquist limits), frame rates, and color gain.
The size of color jet area changes dramatically with different PRF settings.
Increasing PRF will decrease the …………………..and vice versa. Fig 5.1
Increasing PRF will decrease the apparent size of a regurgitant jet and vice versa. Fig 5.1
The American society of echocardiography recommends setting the Nyquist limit between …….. cm/sec.
Gain should be turned ip to see color speckling and then turned back until speckling disappears..
Nyquist limit between 50 and 60 cm/sec.
Using consistent and similar settings on the echo equipment will help minimize errors in assessment and provide more accurate evaluation of changes over serial studies.
Color-flow settings for regurgitation:
Set gain just below level where speckle occurs.
Optimize frame rate: how?
Decrease 2D sector size
Decrease color sector size
Adjust packet size
Adjust smoothing and frame averaging
Jet area increases with decreasing PRF
Ideally set PRF to 50-60 cm/sec
Eccentric jets can limi the ability to assess severity. Jets that slide along a lateral wall of the receiving chamber flatten out because of the ……effect
The Coanda effect.
This reduces spread into the chamber.
These eccentric jets will appear much smaller than jets of comparable severity that are centrally directed.
Color-flow Doppler regurgitant jet areas are also affected by driving pressure. Jet area increases and decreases with changes in driving pressure. Therefore, it is important to measure ……and take medications into consideration when assessing regurgitant severity.
blood pressure
The evaluation of valvular regurgitation by echo must consider the patient’s clinical status. Why?
Physiological changes can alter the results between echocardiographic examinations of the same patient.
Physiologic MR in animals is less common than insufficiencies at the other cardiac valves.
Physiologic MR in animals is less common than insufficiencies at the other cardiac valves.
Both the size and duration of valvular leaks help differentiate between physiologic and pathologic regurgitation. Physiologic regurgitation has low velocity, occupies a small area behind the valve, and rarely encompasses the entire portion of systole or diastole. These small leaks are often associated with valve closure and are called?
Trace regurgitation or mitral closing volume.
Physiologic regurgitation has:
Low velocity Weak flow profile Is trivial in size just behind the valve Is generally nonturbulent Is not holosystolic or holodiastolic
Low velocity Weak flow profile Is trivial in size just behind the valve Is generally nonturbulent Is not holosystolic or holodiastolic
Trace or mild MR seen in ….10% of normal healthy dogs
approximately 10 %
Slight rounding and curling at the tips of the mitral valve leaflets are consistent with early degenerative changes.
Fig 5.2
Mitral valvular lesions may become very large and irregular. Can echo differentiate between degenerative and vegetative lesions?
No.
Fig 5.3
Bowing of the inter ventricular and atrial septum’s toward the right indicates?
Dilation of both the LV and LA.
Fig 5.3
A small nonturbulent flow area located proximal to the mitral valve leaflets during early systole usually represents….?
…. back flow secondary to valve closure.
This usually last for a very short time. (
The typical characteristics of myxomatous degeneration include?
- LV and LA dilation
- Wall and septal hypertrophy
- Increased thickness, nodularity, and prolapse of one or both mitral valve leaflets
- Elevated parameters of systolic function
- Hyperdynamic wall and septal motion
Less common features include pericardial effusion, lack of hypertrophy, decreases in systolic function, and ruptured chordae tendineae
The degenerative mitral valve changes eventually prevent proper leaflet alignment and closure. The lesions are generally smooth and small creating a club-shaped appearance to the leaflet tips during early stages of the disease but may become large and irregular as the disease progresses. Generally, but not always, larger lesions are associated with more severe insufficiency.
Figures 5.2, 5.3, 5.4
Large breed dogs with acquired mittal valve insufficiency seem to have fewer observable changes of the valve leaflets despite significant regurgitation. Prolapse may be observed without any abnormal thickness or irregularity of the leaflets.
Large breed dogs with acquired mittal valve insufficiency seem to have fewer observable changes of the valve leaflets despite significant regurgitation. Prolapse may be observed without any abnormal thickness or irregularity of the leaflets.
The identification of lesions is………..dependent (3)
Gain
Depth
Transducer dependent
It is good to compare the leaflets to other structures at that approximate depth. The thickness of endocardial echoes is used to assess leaflet thickness in man. They should be similar.
When mitral lesions are small, be careful to interrogate several planes since chordal attachments to the leaflets are difficult to distinguish from lesions.
Fig 4.9
Right parasternal 4 ch views of the heart are excellent for imaging the mitral valve (fig 5.3). The LV inflow outflow vies is also good, but the valves may appear to be thicker than they truly are if the imaging plane is not perfect.
Right parasternal 4 ch views of the heart are excellent for imaging the mitral valve (fig 5.3). The LV inflow outflow vies is also good, but the valves may appear to be thicker than they truly are if the imaging plane is not perfect.
The sound beam needs to be directed throughout the center of the annulus, and to do so the probe needs to be lifted up toward the animal’s thorax creating a clean LA with leaflets that move and open well into the LV. Are transverse images valuable?
Transverse images of the valve are useful of identifying large lesions, but they can be misleading when looking for small ones. Fig 5.5
The nodular leaflets appear …………and………. on M-mode images.
The nodular leaflets appear shaggy and irregular on M-mode images. Fig 5.6.
Although it is not common, there may be ……….. fluttering of the mitral valve on M-mode images as the regurgitant jet flows through it.
When lesions are large the thickness of the mitral valve on the image masks the fluttering.
Although it is not common, there may be systolic fluttering of the mitral valve on M-mode images as the regurgitant jet flows through it.
When lesions are large the thickness of the mitral valve on the image masks the fluttering.
Degenerative mitral valve disease is the most common cause of ruptured chordae tendineae in the dog. Can vegetative growth of the mitral valve also result in ruptured chordae tendineae?
Rarely
The mitral valve has …………….. chordae tendineae, which attach the tips of the leaflets to the papillary muscles and are responsible for most of the structural integrity of the valve.
The mitral valve has primary or first order chordae tendineae, which attach the tips of the leaflets to the papillary muscles and are responsible for most of the structural integrity of the valve.
Secondary and tertiary chordae tendineae attach the ……………. of the valve leaflets and the …………… area of the leaflets to the papillary muscles and ventricular walls.
Secondary and tertiary chordae tendineae attach the midventricular portions of the valve leaflets and the commissural area of the leaflets to the papillary muscles and ventricular walls.
The majority of dogs with echo evidence of ruptured chordae tendinea have ………… mitral insufficiency based upon color-flow Doppler evaluation of regurgitant jet size and heart failure class.
The majority of dogs with echo evidence of ruptured chordae tendinea have severe mitral insufficiency based upon color-flow Doppler evaluation of regurgitant jet size and heart failure class.
Most instances of ruptured chordae affect the ……. leaflet of the mitral valve, and ruptured of chordae to the ……… (posterior) leaflet is much less common.
Most instances of ruptured chordae affect the septal leaflet of the mitral valve, and ruptured of chordae to the parietal (posterior) leaflet is much less common.
Rupture of a chordae tenineae resulting in a flail leaflet is diagnosed when ……………?
Rupture of a chordae tenineae resulting in a flail leaflet is diagnosed when the leaflet points back into the LA chamber during systole.
Fig 5.7, 5.8, 5.9
During diastole, the leaflet may sometimes bend back on itself within the LV outflow tract.
Fig 5.10, 5.11
The mitral valve shows chaotic motion during diastole and systole on both M-mode and RT images after a chordae has ruptured.
Fig 5.12
These findings are seen on both parasternal and apical images.
Minor chordal rupture may be seen in only one echocardiographic plane while major chordal rupture tends to be seen in several imaging planes.
Minor chordal rupture may be seen in only one echocardiographic plane while major chordal rupture tends to be seen in several imaging planes.
The CF jet of MR caused by chordal rupture is usually…
Eccentric
When Doppler confirms the presence of severe MR without the concurrent LV and LA dilation seen i a chronic process, look for …………………..
When Doppler confirms the presence of severe MR without the concurrent LV and LA dilation seen i a chronic process, look for a ruptured chordae.
Fig 5.13
An eccentric regurgitant jet implies the presence of ?
Prolapse or flail leaflets.
Papillary muscle rupture occurs. This is usually a consequence of ….?
trauma
M-mode echo shows an abnormal mass moving within the LV chamber, but 2D images provide clear visualization of the torn muscle and its movement within the chamber. The 2D echo features of papillary muscle rupture include …?
….visualization of a portion of the papillary muscle attached to the chordae tendineae, severe mitral valve prolapse, or flail leaflets, and abnormal appearance of the papillary muscle where the tip of it has torn off.
Mitral valve prolapse (MVP) may be primary or secondary.
Primary MVP results from?
Intrinsic abnormalities of the mitral valve leaflets, usually myxomatous degeneration.
Secondary MVP is present without inherent pathologic valvular abnormalities. This is typically secondary to?
Hemodyanmic causes such as volume contraction and reduced LV size or myocardial disease resulting in akinetic muscle and abnormal papillary muscle function.
When secondary or tertiary chordal rupture is present, the body of the leaflet billows back into the atrial chamber and only prolapse is appreciated.
When secondary or tertiary chordal rupture is present, the body of the leaflet billows back into the atrial chamber and only prolapse is appreciated.
When both mitral valve leaflets are involved in the degenerative process with either valvular prolapse or irregularity, the prognosis for survival becomes poorer.
When both mitral valve leaflets are involved in the degenerative process with either valvular prolapse or irregularity, the prognosis for survival becomes poorer.
In dogs, prolapse of the mitral valve is usually secondary to …..?
In dogs, prolapse of the mitral valve is usually secondary to myxomatous degeneration of the leaflets, chronic stretch of the chordae tendineae and redundancy into the atrium during systole.
MVP may be seen without any evidence of insufficiency and seems to be genetically influenced in CKCS and Dachshunds.
MVP may be seen without any evidence of insufficiency and seems to be genetically influenced in CKCS and Dachshunds. These dogs tend to show prolapse as early as 3 years of age without any clinical signs or murmurs and have a high incidence of mitral valvular
insufficiency later in life.
Of 19 CKCS dogs with mitral valvular insufficiency in one study, 84% had MVP
3 year-old Dachshunds without heart murmur had a 47% incidence of MVP.
MVP prolapse can be secondary to?
-Degenerative valve disease
Or hemodynamic causes
- Akinetic or dyskinetic myocardium
- Abnormal papillary muscle function
The course of MVP in man is usually benign. What about in dogs?
The course of MVP in man is usually benign but this is not so in dogs where there is greater incidence of degenerative valvular disease. Dogs have more significant insufficiency and higher classes of heart failure with mitral valve prolapse.
When is the diagnosis of MPV made?
When one or both leaflets buckle back toward the LA during systole.
The mitral valve annulus is identified by?
A line drawn from the base of the aortic valve to the point of attachment of the parietal mitral valve leaflet on right parasternal long-axis LV outflow views or by a line joining the attachment point of both mitral leaflets on right parasternal 4 ch views. Fig 5.14, Fig 5.15
Normally, the body of the mitral valve leaflets does not extend beyond the line into the LA. Buckling of either leaflet into the atrium beyond this line indicates mild mitral valve prolapse.
Normally, the body of the mitral valve leaflets does not extend beyond the line into the LA. Buckling of either leaflet into the atrium beyond this line indicates mild mitral valve prolapse.
A line drawn further back into the atrium from the dense echogenic area at the ………… part of the atrial septum to the ………………… behind the posterior mitral valve leaflet represents the border between mild and severe prolapse/MVP.
A line drawn further back into the atrium from the dense echogenic area at the lower part of the atrial septum to the atrioventricular junction behind the posterior mitral valve leaflet represents the border between mild and severe prolapse/MVP. Fig 5.16 and 5.17.
One study showed that the diagnostic accuracy of detecting MVP increases with experience.
One study showed that the diagnostic accuracy of detecting MVP increases with experience.
Apical 4 ch views are not recommended for the diagnosis of MVP in man, since this plane through the mitral annulus shows normal curving of the anterior leaflet into the left atrium. Only when the septal leaflet bends greater than 1 cm into the LA on apical 4 ch views is it considered abnormal in man. What about Posterior leaflet buckling in the apical 4 ch view: Is this also a normal finding?
Posterior leaflet buckling in the apical 4 ch view is always abnormal.
Parasternal LV long-axis views are recommended in man.
The accuracy of diagnosis MVP on apical 4 ch views has not been studied in animals.
Volume overload of the LA and LV is seen with hemodynamically significant chronic mitral valvular insufficiency. The degree of LA enlargement is often used as an indicator of stage of heart failure based upon New York Heart Association criteria
Volume overload of the LA and LV is seen with hemodynamically significant chronic mitral valvular insufficiency. The degree of LA enlargement is often used as an indicator of stage of heart failure based upon New York Heart Association criteria
The atrial sizes of dogs in stage 3 and 4 of the NYHA criteria are significantly larger than the atria of stage 2. LA sizes of dogs in stage 2 failure were significantly larger than the atria of dogs with no heart failure or stage 1 heart failure.
The atrial sizes of dogs in stage 3 and 4 of the NYHA criteria are significantly larger than the atria of stage 2. LA sizes of dogs in stage 2 failure were significantly larger than the atria of dogs with no heart failure or stage 1 heart failure.
There is no difference between the atrial sizes of dogs with stage 1 heart failure and no heart failure.
There is no difference between the atrial sizes of dogs with stage 1 heart failure and no heart failure.
Significant insufficiencies without the concurrent chamber enlargement are suggestive of?
An acute process and ruptured chordae. Fig 5.13
LA to aortic root ratios of greater than 1.7 have been found to be spoor prognostic indicator for survival.
LA to aortic root ratios of greater than 1.7 have been found to be spoor prognostic indicator for survival.
In dogs with normal systolic function or mildly depressed systolic function, the degree of LA dilation correlates well with severity of the regurgitant volume.
In dogs with normal systolic function or mildly depressed systolic function, the degree of LA dilation correlates well with severity of the regurgitant volume.
Mild LA enlargement may be seen in dogs with early MR before there is any measurable ventricular dilation. 2D images should be used in various planes in order to determine if enlargement is present (may not be apparent on the M-mode).
Echo evidence of mild LA dilation may be more accurate than radiographic assessment because of the objective versus subjective measuring involved.
In dogs with normal systolic function or mildly depressed systolic function, the degree of LA dilation correlates well with severity of the regurgitant volume.
The LA/Ao ratio is used to evaluate atrial size. As the severity of MR increases, however, this ratio may not accurately reflect increases in atrial size. Aortic root size may decrease with ………………….. flow. This decrease in aortic root size is also seen in ……… circulating blood volume.
The LA/Ao ratio is used to evaluate atrial size. As the severity of MR increases, however, this ratio may not accurately reflect increases in atrial size. Aortic root size may decrease with reduced forward flow. This decrease in aortic root size is also seen in low circulating blood volume.
Severe LA enlargement and concurrent high LA pressures in dogs with mitral valvular disease can on rare occasions result in rupture of the atrial septum creating an……… defect or it may tear in the……… wall of the atrium or auricular appendage resulting in fluid accumulation within the pericardial sac.
Severe LA enlargement and concurrent high LA pressures in dogs with mitral valvular disease can on rare occasions result in rupture of the atrial septum creating an atrial septal defect or it may tear in the lateral wall of the atrium or auricular appendage resulting in fluid accumulation within the pericardial sac.
Echo evidence of fluid accumulation within the sac will be seen.
Pericardial effusion occurs seondary to CHF, but the presence of a thrombus within the pericardial space confirms the diagnosis of atrial splitting since pericardial effusions secondary to neoplasm, pericarditis, or heart failure do ………………………..
Pericardial effusion occurs seondary to CHF, but the presence of a thrombus within the pericardial space confirms the diagnosis of atrial splitting since pericardial effusions secondary to neoplasm, pericarditis, or heart failure do not tend to form clots. Fig. 5.21
Thrombus within the pericardial space develops linear layers of ……. material that conforms to the shape of the heart.
hyperechoic material
Fig 5.22, 5.23
Tumors within the pericardial sac are generally more …….
rounded and not laminar in appearance.
Thrombus in the pericardial sac manifests itself in ………….. that conform to the shape of the sac. Round or oval soft tissue shapes are usually tumors.
Thrombus in the pericardial sac manifests itself in linear echoic layers that conform to the shape of the sac. Round or oval soft tissue shapes are usually tumors.
Mitral valve motion may refelct elevated LV diastolic pressures. Closure of the mitral valve is ……….. after atrial contraction, and a ….bump or shoulder is described in animals and man.
This motion is reported to occur in animals where LV diastolic pressures exceed ….. mmHg
Closure of the mitral valve is delayed after atrial contraction, and a B bump or shoulder is described in animals and man.
Fig 4.99, 5.24
> 30 mmHg
Motion of the interventricular septum and free wall are exaggerated in animals with MR, volume overload, and preserved myocardial function. This is secondary to?
Secondary to the increased volume flowing into and out of the LV chamber relative to the volume filling the RV chamber.
Septal motion may be greater than free wall motion since it is affected to a greater degree by volume changes in the right and left ventricles.
Septal motion may be greater than free wall motion since it is affected to a greater degree by volume changes in the right and left ventricles. Fig 5.25
Aortic valve motion may be abnormal in animals with significant MR. Blood will flow into the lower pressure LA instead of the higher pressure systemic circulation as systole progresses and ………… closure of the aortic valve is seen. A ………. shaped aortic valve is seen on M-mode images as opposed to a …………. shape during systole.
Aortic valve motion may be abnormal in animals with significant MR. Blood will flow into the lower pressure LA instead of the higher pressure systemic circulation as systole progresses and gradual closure of the aortic valve is seen. A triangular shaped aortic valve is seen on M-mode images as opposed to a rectangular shape during systole. Fig 4.96
2 D and M-mode features of MR:
Degenerative valvular lesions LA and LV dilation Exaggerated IVS and LVW motion Possible delayed MV closure Possible gradual Av closure.
left ventricular function: Fractional shortening (FS) as a measure of myocardial function in dogs with chronic degenerative mitral valve insufficiency should be elevated because of the presence of.....?
Increased preload, decreased afterload, and generally increased contractile properties.
Fig 5.26
Is there a correlation between the stage of heart failure based upon American Heart Association criteria and the fractional shortening?
No
Congestive heart failure in dogs with chronic mitral insufficiency is secondary to severe regurgitation and volume overload of the left atrium and ventricle, not myocardial failure in most cases.
Fig 5.26
Normal myocardial contractility results in a ……… LV systolic chamber size no matter how dilated the LV becomes.
Normal myocardial contractility results in a normal LV systolic chamber size no matter how dilated the LV becomes.
Studies show that using fractional shortening and systolic dimensions or systolic index in dogs can separate dogs with abnormal myocardial function from those with normal myocardial function.
Therefore, while fractional shortening is dependent upon preload, afterload, and contractility, ………….. and …………….. are not affected by preload.
Studies show that using fractional shortening and systolic dimensions or systolic index in dogs can separate dogs with abnormal myocardial function from those with normal myocardial function.
Therefore, while fractional shortening is dependent upon preload, afterload, and contractility, systolic dimensions and systolic index are not affected by preload.
Hearts with normal myocardial contractility will shorten to …………. systolic dimensions regardless of how dilated the heart becomes.
Hearts with normal myocardial contractility will shorten to normal systolic dimensions regardless of how dilated the heart becomes.
Only when the intrinsic contractility of the myocardium starts to fail will …………. dimensions become larger than normal.
Only when the intrinsic contractility of the myocardium starts to fail will systolic dimensions become larger than normal.
Fig 4.56,4.57, 5.27
Only when the intrinsic contractility of the myocardium starts to fail will systolic dimensions become larger than normal.
Using this as an indicator, Kittleson found that dogs have a normal systolic index of less than ….. ml/m2.
30
Dogs with an index of greater than ………. ml/m2 had severe myocardial failure, dogs with a systolic index ranging from 52 +/- 6 ml/m2 have mild myocardial impairment, and dogs between these two ranges with a mean of ……… ml/m2 have moderately reduced myocardial contractility.
Dogs with an index of greater than 100 ml/m2 had severe myocardial failure, dogs with a systolic index ranging from 52 +/- 6 ml/m2 have mild myocardial impairment, and dogs between these two ranges with a mean of 73 ml/m2 have moderately reduced myocardial contractility.
The volume equation used in this study was Teichholz.
Systolic index is calculated by?
Systolic index is calculated by dividing the end-systolic volume by BSA.
One study suggested that a LV systolic index of greater than ….. ml/m2 is associated with a poor survival time.
One study suggested that a LV systolic index of greater than 30 ml/m2 is associated with a poor survival time.
Assessment of function with MR:
Normal myocardial function:
Systolic index ……. ml/m2
Normal myocardial function:
Systolic index
Assessment of function with MR:
Severe myocardial failure:
Systolic index ……… ml/m2
Severe myocardial failure:
Systolic index > 100 ml/m2
Assessment of function with MR:
Moderate myocardial failure:
Systolic index ca …….. ml/m2
Moderate myocardial failure:
Systolic index 70- 100 ml/m2
Mild myocardial failure:
Systolic index ca ……….. ml/m2
Mild myocardial failure:
Systolic index 34-70 ml/m2
There are conflicting data regarding the presence of myocardial failure in dogs with chronic degenerative mitral valve disease. ……. breed dogs tend to develop myocardial failure secondary to chronic mitral valve disease more often than ……. breed dogs.
Large breed dogs tend to develop myocardial failure secondary to chronic mitral valve disease more often than small breed dogs.
Normal small and large breed dogs seem to have different systolic v’’’’’
olume indexes, therefore, it may be more accurate to assess myocardial function by calculating a ratio of ….?
A ratio of systolic dimension compared to expected systolic dimension for the body weight.
Dogs were diagnosed with myocardial failure if the end systolic dimension to end systolic dimension expected ratio was greater than normal. Normal in large breed dogs and small breed dogs?
Large breed dogs: 1.13 +/- 0.15
Small breed dogs: 0.89 +/- 21
The expected end systolic dimension is based upon allometric ratios and calculated by using equation 5.1 where ESDe is end systolic expected dimension and BW is body weight:
ESDe =0.95 x BW upphöjt i 0.315
Allometric ratios show a difference in percent change in area of the LV chamber during contractility between normal dogs and dogs with degenerative mitral valve disease. A weighted change in area of ……. or greater differentiated the normal dogs from those with degenerative valve disease.
A weighted change in area of 2.1 or greater differentiated the normal dogs from those with degenerative valve disease.
This is nor necessarily that useful, but a further application of these ratios showed the ability to differentiate dogs with mitral regurgitation that were not in left-sided CHF from those that were.
This may have the potential to become a predictive variable for the development of CHF.
A weighted LA dimension was 76% sensitive and 81% specific at differentiating the two groups with a weighted LA size of ……… or greater.
A weighted LA dimension was 76% sensitive and 81% specific at differentiating the two groups with a weighted LA size of 1.55 or greater.
In order to weight these variable, they are compared to the M-mode derived aortic dimension.
The aorta is normalized to the animal’s weight by using the following equation:
AOw = 0.795 x W upphöjt i 1/3
where W is the dog’s weight in kg. The measured M-mode numbers are then divided by the weighted aortic value.
Weighted LA size:
predictive value for development of CHF?
> /= 1.55 = predictive for development of CHF
Lack of adequate hypertrophy is one factor that causes diminished myocardial function in dogs with LV volume overload secondary to chronic mitral valve disease.
Lack of adequate hypertrophy is one factor that causes diminished myocardial function in dogs with LV volume overload secondary to chronic mitral valve disease.
High ……… and increased wall ……… is the stimulus for hypertrophy, and volume overload may not provide an adequate stimulus for good compensatory hypertrophy as the heart dilates to make up for the valvular regurgitation.
High afterload and increased wall stress is the stimulus for hypertrophy, and volume overload may not provide an adequate stimulus for good compensatory hypertrophy as the heart dilates to make up for the valvular regurgitation.
The normal response to increased afterload is ……………. This normalizes wall stress.
The normal response to increased afterload is hypertrophy. This normalizes wall stress.
Wall stress is determined by the ratio of radius to wall thickness as seen in the equation:
Wall stress = (P x r)/h
Where h = wall thickness, r = radii, P = systolic blood pressure
An increase in this ratio results in high wall stress and a decrease results in low wall stress.
The eccentric hypertrophy pattern seen with mitral insufficiency has a normal to high wall stress value since hypertrophy is usually …………..
The eccentric hypertrophy pattern seen with mitral insufficiency has a normal to high wall stress value since hypertrophy is usually limited.
MMVD:
During LV contraction, there is movement of blood into the low pressure LA chamber. This decreases the impetus for development of hypertrophy to compensate for the volume overload of MR.
The thin walls however are very ……….. and allow for enhanced ventricular filling and increased stroke volume. Still, hearts with MR have the lowest mass-to-……….. ratio, even less than hearts with aortic regurgitation.
The thin walls however are very compliant and allow for enhanced ventricular filling and increased stroke volume. Still, hearts with MR have the lowest mass-to-flume ratio, even less than hearts with aortic regurgitation.
When systolic function is reduced in hearts with LV volume overload secondary to MR, wall stress is very ……..because of this low wall-to-chamber radius ratio. This is thought to contribute to progressive LV systolic failure.
When systolic function is reduced in hearts with LV volume overload secondary to MR, wall stress is very high because of this low wall-to-chamber radius ratio
Increased wall stress because of …….. wall thickness to chamber size ratio is thought to contribute to progressive LV systolic failure.
Increased wall stress because of low wall thickness to chamber size ratio is thought to contribute to progressive LV systolic failure.
Measurement of wall thickness to chamber size is a way to evaluate the degree of compensatory hypertrophy
The diastolic dimension of the LV chamber is divided in half to provide a radius measurement and the wall thickness (..) to chamber radius (…) is calculated.
Measurement of wall thickness to chamber size is a way to evaluate the degree of compensatory hypertrophy
The diastolic dimension of the LV chamber is divided in half to provide a radius measurement and the wall thickness (h) to chamber radius (r) is calculated.
Normal wall thickness to chamber radius in large breed dogs and small breed dogs?
Dogs 20 kg: 0.47 +/- 0.11
FS is also used to divide dogs with MMVD into various categories of impaired contractility:
Dogs with any degree of mitral insufficiency from mild to severe whether they are in CHF or not will have FS ——— if they have no myocardial dysfunction.
FS above the normal range if they have no myocardial dysfunction.
Dogs with mild to moderately impaired myocardial contractility will have FS within the normal range of ……..%
33-45%
Severe myocardial failure is present when FS is below the normal range.
Mitral annular motion (MAM) taken from M-mode recordings of the mitral annulus on left apical 4 ch views becomes depressed if there is myocardial failure. Does this become depressed in most dogs with MMVD?
No, not in most dogs with MMVD but it is depressed in dogs with cardiomyopathy. Fig 5.28
Mitral annular motion (MAM) measures ………. shortening of the LV chamber and may be different from ……… fiber shortening, which is what is measured for fractional shortening.
Mitral annular motion (MAM) measures longitudinal shortening of the LV chamber and may be different from circumferential fiber shortening, which is what is measured for fractional shortening.
This may help differentiate normal from abnormal systolic function in some equivocal cases.
Color-flow Doppler evaluation:
Using this modality, and paying attention the the jet area with respect to the receiving chamber, the area of flow ……., and the jet …….. at its origin significantly improves the evaluation of severity of the regurgitation.
Color-flow Doppler evaluation:
Using this modality, and paying attention the the jet area with respect to the receiving chamber, the area of flow convergence, and the jet width at its origin significantly improves the evaluation of severity of the regurgitation.
Color-flow analysis of regurgitation uses:
Jet area
Flow convergence
Vena contracta
Jet size:
Pathological regurgitation can be semiquantitatively assessed by measuring the size of the color-flow jet within the atria in the case of AV valvular insufficiency or within the outflow tract or ventricle in the case of aortic or pulmonic insufficiency.
Pathological regurgitation can be semiquantitatively assessed by measuring the size of the color-flow jet within the atria in the case of AV valvular insufficiency or within the outflow tract or ventricle in the case of aortic or pulmonic insufficiency.
In man, mitral or tricuspid insufficiency jets that occupy less than …. % of the atrium are mild insufficiency. A jet that occupies … to ….% of the atrial area represents moderate insufficiency and when greater than …. % of the atrium is filled by aliased flow of regurgitation, it si classified as severe insufficiency.
In man, mitral or tricuspid insufficiency jets that occupy less than 20% of the atrium are mild insufficiency.
A jet that occupies 20 to 40% of the atrial area represents moderate insufficiency and when greater than 50% of the atrium is filled by aliased flow of regurgitation, it si classified as severe insufficiency.
This method uses the largest regurgitation jet found in any plane.
Studies that average the jet size over several imaging planes do not show any significant improvement in predicting severity.
Assessment of MR based upon color jet area is the poorest of the color-flow assessment methods because of the technical factors mentioned previously, such as?
Gain
PRF
Fram rate
ec, as well as for the following situations:
When the systemic pressures driving the regurgitant jet are abnormal, these percentages are no longer accurate. The driving pressure affects the velocity of the color-flow jet and the area that it encompasses.
One in vitro study showed that an equal volume of regurgitation blood displayed varying sizes of color-flow jets based upon the pressure driving the regurgitant jet. Low systemic pressure and high LA pressure can show small jet areas despite having severe regurgitation, and high systemic pressure can cause a regurgitant jet to be quite large despite having mild insufficiency.
One in vitro study showed that an equal volume of regurgitation blood displayed varying sizes of color-flow jets based upon the pressure driving the regurgitant jet. Low systemic pressure ans high LA pressure can show small jet areas despite having severe regurgitation, and high systemic pressure can cause a regurgitant jet to be quite large despite having mild insufficiency.
Abnormal systemic pressure (low or high) makes jet area assessment of MR inaccurate
Abnormal systemic pressure (low or high) makes jet area assessment of MR inaccurate
Heart rate also affects regurgitant jet size. How?
Fast heart rates rend to result in underestimation of the degree of insufficiency when assessed with CF Doppler
Eccentric regurgitation jets limit the accuracy of using jet are for classification of severity. Why? This is called the ……… effect
An eccentric jet, which is commonly seen in the presence of mitral valve prolapse, causes the jet to hug the atrial walls. This prevents the jet from dispersing into the atrial chamber, turbulence is no longer as apparent, which results in underestimation of regurgitant severity. This is called a Coanda effect. Fig 5.36
When is the regurgitant/area assessment reliable?
When the regurgitant jet is centrally directed and there is a normal sinus rhythm, then the assessment of severity using CF-Doppler is usually reliable.
Other methods that attempt to overcome some of these limitations have been investigated. Muzzi et al calculated a MR jet area to left atrial ……….. in …….. ch imaging planes in dogs. A ratio of 70% of left atrial area occupied by the regurgitant jet correlated with severe mitral regurgitation based upon comparison to other Doppler-derived calculations of regurgitant fractions and volumes as well as effective regurgitant orifice area.
Muzzi et al calculated a MR jet area to left atrial area in apical 4 ch imaging planes in dogs. A ratio of 70% of left atrial area occupied by the regurgitant jet correlated with severe mitral regurgitation based upon comparison to other Doppler-derived calculations of regurgitant fractions and volumes as well as effective regurgitant orifice area.
Fig 5.37
The correlation between regurgitant fraction and the area of the regurgitant jet measured from color Doppler was weak (r= 0.59), but correlation between regurgitant fraction and left atrial area was strong. (r= 0.88)
Evaluation of the ratio or regurgitant jet area to left atrial size is a reproducible measurement with little variation
When ruptured, chordae tendineae are a factor in the degree of regurgitation, however the severity of regurgitation assessed by color-flow jet area to left atrial area did not correlate with class of heart failure and clinical signs in a study.
When ruptured, chordae tendineae are a factor in the degree of regurgitation, however the severity of regurgitation assessed by color-flow jet area to left atrial area did not correlate with class of heart failure and clinical signs in a study.
There may be different clinical consequences when primary, secondary, or tertiary chordae rupture.
There may be different clinical consequences when primary, secondary, or tertiary chordae rupture.
Jet area can also be assessed by …….. Doppler if the time is taken to place a PW gate at various points in the atrium in order to assess the extent of the jet.
Jet area can also be assessed by spectral Doppler if the time is taken to place a PW gate at various points in the atrium in order to assess the extent of the jet.
Ratio of MR jet area to LA area:
70% = severe MR
Regurgitant jet area correlates well with regurgitant volume
Left atrial area correlates well with regurgitant fraction.
If MR was secondary to ruptured chordae tendinaea these above mentioned measurements were not accurate.
Regurgitant jet area correlates well with regurgitant volume
Left atrial area correlates well with regurgitant fraction.
If MR was secondary to ruptured chordae tendinaea these were not accurate.
Concern over the effects of gain, pulse repetition frequency, size of the dog, and heart rate on the assessment of CF evaluation of severity of regurgitation has led to studies that utilize other methods of assessing CF regurgitant jets.
Concern over the effects of gain, pulse repetition frequency, size of the dog, and heart rate on the assessment of CF evaluation of severity of regurgitation has led to studies that utilize other methods of assessing CF regurgitant jets.
One study in dogs uses ratios of regurgitant to forward flow. Frames displaying the largest color-flow areas are used. Regurgitant jets are traced and a MR jet mapping area was determined (MRMA) as well as the CF-area representing aortic forward flow (AFMA).
The ratios of these 2 areas (MRMA/AFMA) correlated well to the New York Heart Association classification of heart failure. This method may eliminate machine and user variation. Additionally it may help stage heart failure more appropriately by helping to differentiate the clinical signs of heart failure from other causes such as exercise intolerance due to aging and joint disease.
What is Proximal Isovelocity Surface Area (PISA)?
Is an area of flow acceleration and convergence proximal to the mitral valve as the regurgitant jet approaches the regurgitant orifice.
PISA: This method assumes that flow accelerates as it approaches the small orifice and that it does so in………………. on the ventricular side of the valve..
This method assumes that flow accelerates as it approaches the small orifice and that it does so in concentric hemispheres on the ventricular side of the valve..
The more blood volume that moves backward throughout the valve the larger the proximal hemisphere is.
The more blood volume that moves backward throughout the valve the larger the proximal hemisphere is.
Studies have shown that this measurement can be used to determine not only the regurgitant orifice area but also ………..?
Studies have shown that this measurement can be used to determine not only the regurgitant orifice area but also regurgitant fraction and volume when used in conjunction with regurgitant flow velocity.
PISA:
Use apical 4 ch view
Use centrally directed MR jet
See flow convergence, vena contracta, and jet expansion
Nyquist limit should be ……… cm/sec
Use largest MR jet during mid systole
- Use zoom
- Adjust baseline in direction of regurgitation until perfect hemisphere is seen
- Nyquist limit should now be ca ……….. cm/sec
Use apical 4 ch view
Use centrally directed MR jet
See flow convergence, vena contracta, and jet expansion
Nyquist limit should be 50-70 cm/sec
Use largest MR jet during mid systole
- Use zoom
- Adjust baseline in direction of regurgitation until perfect hemisphere is seen
- Nyquist limit should now be ca 18 to 40 cm/sec
In order to record and measure the proximal isovelocity hemisphere, the mitral regurgitant jet is identified on an apical 4 ch view. The proximal flow convergence, the vena contracta and the regurgitant jet should all be visualize and the Nyquist limit should be set somewhere between 50 and 70 cm/sec.
Fig 5.38
The lack of flow convergence area is consistent with …………. while the presence of a large flow convergence area is consistent with a significant regurgitant volume. Fig 5.39
The lack of flow convergence area is consistent with minimal to milc regurgitation while the presence of a large flow convergence area is consistent with a significant regurgitant volume. Fig 5.39
The largest regurgitant jet during peak to ………. should be isolated on fram-by frame images. Zooming in on the mitral valve at the location of flow convergence will optimize measurement accuracy.
The largest regurgitant jet during peak to mid-systole should be isolated on fram-by frame images. Zooming in on the mitral valve at the location of flow convergence will optimize measurement accuracy.
The baseline of the color map should be moved downward in the direction of regurgitation until the flow convergence area has a hemisphere of solid color outlined in the aliased signal. The Nyquist limit (Va in cm/sec) should be somewhere between …. and ….. cm/sec when this hemisphere is seen.
The Nyquist limit (Va in cm/sec) should be somewhere between 18 and 40 cm/sec when this hemisphere is seen.
The Nyquist limit at which the radius is measured is not the most important factor, the important features is that …..?
the flow convergence area is as close to a perfect hemisphere as possible.
The following factors should be recorded and measured:
Tadius of the hemisphere of the proximal flow convergence (r in cm)
The peak mitral regurgitant velocity (MRvmax in cm/sec) and its velocity time integral (MRvti in cm). Fig 5.40
Flow rate, effective regurgitant orifice area (EROA) and regurgitant vole (RV) are calculated as follows in equations 5.4 to 5.6
Equations 5.4-5.6
Notice that the EROA in the regurgitant volume equation is in …………….., remember to convert the MRvmx to cm/sec if your machine calculate it in m/sec, and if your equipment reports EROA in mm upphöjt i 2, remember to change it to cm upphöjt i 2 if you are calculating regurgitant volume manually.
Notice that the EROA in the regurgitant volume equation is in cm upphöjt i 2, remember to convert the MRvmx to cm/sec if your machine calculate it in m/sec, and if your equipment reports EROA in mm upphöjt i 2, remeber to change it to cm upphöjt i 2 if you are calculating regurgitant volume manually.
Effective regurgitant orifice areas of /= ……cm upphöjt i 2 is consistent with a severe MR
Effective regurgitant orifice areas of /= 0.4 cm upphöjt i 2 is consistent with a severe MR
PISA-EROA (man)
mild MR
PISA-EROA (man)
0.2-0.39 cm upphöjt i2 = ….MR
Moderate MR
PISA-EROA (man)
0.4 cm upphöjt i2 = ….MR
Severe MR
The PISA method requires an …………. hemisphere and excellent alignment with a centrally directed regurgitant jet. Misalignment with an ………. jet will underestimate orifice areas.
The PISA method requires an elliptical hemisphere and excellent alignment with a centrally directed regurgitant jet. Misalignment with an eccentric jet will underestimate orifice areas.
Hemicircles measured too close to the mitral orifice are generally too …….., which will …………. flow rates
Hemicircles measured too close to the mitral orifice are generally too flat, which will underestimate flow rates
Convergence hemispheres too far away typically maintain too much of a …….. shape and will ……….. flow rates.
Convergence hemispheres too far aways typically maintain too much of a parabolic shape and will overestimate flow rates. Fig 5.41, 5.42.
Try to optimize the flow convergent hemisphere to be as close to a ……… as possible.
Try to optimize the flow convergent hemisphere to be as close to a half circle as possible. Studies have shown good correlation with actual flow rates when flow convergence is recorded and measured accurately (r=0.96)
Three-dimensional imaging with color-flow Doppler has shown that the area of flow convergence varies based upon …………… and three-dimensional ………………… improves accuracy immensely,
Three-dimensional imaging with color-flow Doppler has shown that the area of flow convergence varies based upon imaging plane and three-dimensional reconstruction improves accuracy immensely,
Jet direction and flow convergence shape are affected by …………. and …………………….
Jet direction and flow convergence shape are affected by orifice shape and valve structure.
There is much day-to-day variability in regurgitant fraction calculated via the PISA method in dogs. The ……………..however, has shown a much lesser degree of variability.
There is much day-to-day variability in regurgitant fraction calculated via the PISA method in dogs. The effective regurgitant orifice area (EROA) however, has shown a much lesser degree of variability.
Studies in man have shown that increased severity of MR based upon regurgitant fraction (>50%) or EROA (>40 mm upphöjt i 2) is correlated with?
Poorer outcomes regardless of the class of heart failure these individuals are in at the same time of the evaluation. It has been suggested that further study may determine if calculation of these parameters in asymptomatic dogs with large regurgitant fractions or EROA can be predictive of the course of clinical signs or in determining when to initiate medial therapy.
Kittleson et al showed that by using the PISA method to calculate regurgitant fraction, dogs with severe MR had more than …… % of their LV volume move backward into the LA chamber during systole. Dogs with moderate MR had …….% regurgitant fractions, and dogs with mild MR had less than …..%.
Kittleson et al showed that by using the PISA method to calculate regurgitant fraction, dogs with severe MR had more than 75% of their LV volume move backward into the LA chamber during systole. Dogs with moderate MR had 45-75% regurgitant fractions, and dogs with mild MR had less than 45%.
Using just centrally directed jets, one study in dogs showed excellent repeatability with variation between 8 and 11% in MR fractions using the PISA method. This study also showed that with severe MR, using the regurgitant jet area often resulted in a jet area or LA area of ……. This makes differentiating between dogs with moderate or severe MR or trying to sub classify within the severe group, difficult if not impossible.
1:1.
PISA measures?
Instantaneous flow rate of the regurgitant jet, which means that it is a measure of the largest EROA during the regurgitant time period.
PISA also assumes holosystolic regurgitant flow. This method is not accurate when the insufficiency encompasses only a portion of the systolic time period. Using color M-mode can define the duration of regurgitation.
PISA also assumes holosystolic regurgitant flow. This method is not accurate when the insufficiency encompasses only a portion of the systolic time period. Using color M-mode can define the duration of regurgitation.
PISA is not accurate when the insufficiency encompasses only a portion of the systolic time period.
PISA is not accurate when the insufficiency encompasses only a portion of the systolic time period.
Using color M-mode can define the duration of regurgitation.
Using color M-mode can define the duration of regurgitation.
PISA measures the largest …….
EROA
