Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5769_Библиотеки_им_академика_М_И_Перельмана
.pdf
340 oracic ultrasound
Aortic valve
S: C -.
Clip 58 – Apical 5 chambers scan. The aortic cusps are calcified and
hypomobile. The left ventricle is hypertrophied.
Clip 59 – Apical 5 chambers scan. The aortic cusps are thickened and
hypomobile.
Clip 60 – Apical 5 chambers scan. Congenital aortic valve stenosis. A cusp
is grossly thickened, while the other is thin. There is marked reduction in
systolic excursion of the cusps.
F: C -.
Clip 61 – Apical 5 chambers scan. Stenotic aortic valve. The color Doppler
shows a jet diastolic secondary to valvular insufficiency.
Clip 62 – Apical 5 chambers scan. Similar to the previous case.
Clip 63 – Apical 5 chambers scan. Significant aortic insufficiency.
Tricuspid valve
e presence of tricuspid regurgitation allows the estimation of systolic pressure in the pulmonary artery30.
e calculation is simple and it is based on the sum of the pressure gradient between right
atrium and right ventricle (derived from the speed of the jet regurgitation) and right atrial
pressure, estimated with a good approximation by evaluating the diameter and inspiratory
changes of the inferior vena cava (Tab. 8 and Fig. 40).
Echocardiography 341
Table 8 – Estimation of PVC based on the diameter and respiratory changes in the inferior vena cava
AP measurement Inspiratory reduction CVP
<1,5cm Collapse 0-5mmHg
1,5-2,0cm >50% 5-10mmHg
1,5-2,0cm 33-50% 10-15mmHg
2,0-2,5cm 0-33% 15-20mmHg
>2,5cm Absent >20mmHg
Modified from: Otto CM. T
2002, pp. 739-760.
he practice of clinical echocardiography
, 2nd ed. WB Saunders, Philadelphia PA,
Inspiratory reduction of 47% Inspiratory reduction of 17%
VCI diameter AP=1.92 cm
PAD=10-15 mmHg
Figure 40 – M-mode study of the inferior vena cava. Measurement of the relationships between the
anterior-posterior diameter (AP) of the the inferior vena cava (IVC) measured near the outlet into the
right atrium, the percentage change in inspiration and the estimation of central venous pressure (CVP).
RAP = right atrial pressure.
VCI diameter AP=2.39 cm
PAD=15-20 mmHg
T : C -.
Clip 64 – Apical 4 chambers scan. Presence of mild pericardial effusion
and severe tricuspid reugrgitation.
Clip 65 – Apical 4 chambers scan. Moderate dilatation of the left cavities
and severe left ventricular dysfunction. Color Doppler shows a significant
tricuspid regurgitation.
342 oracic ultrasound
Clip 66 – Apical 4 chambers scan. Severe tricuspid regurgitation in a
patient with significant systolic dysfunction of the left ventricle.
➣ Echocardiographic estimation of systolic pulmonary pressure
31,32,33
is kind of estimation uses continuous-wave Doppler, and similarly to the evaluation of
diastolic function and stroke volume (SV), it is not a properly basic one. It is described here
and in the following chapter, because the pulmonary systolic pressure is important to interpret the right ventricular dysfunction and the acute cor pulmonale, which are common in
the critically ill patient.
Acute cor pulmonale is caused by a sudden increase in right ventricular afterload and is
present in pulmonary embolism, in ARDS, as a side effect of mechanical ventilation, in air
embolism, and in respiratory or metabolic acidosis.
Pulmonary systolic blood pressure can be estimated from the velocity of tricuspid regurgitation jet through the modified Bernoulli equation. Most people (>70%) have some degree
of insufficiency of the tricuspid valve, whereby the flow is frequently samplable. e jet can
be displayed by color Doppler through various cardiac screenings, but the most used are the
apical 4 chambers and parasternal short axis. e sampling line should be aligned as much
as possible with the jet determined by tricuspid regurgitation (Figs. 41, 42).
Generally, ultrasound immediately produces an estimate of the peak pressure gradient between
the right ventricle and atrium, which derives from the speed of the regurgitation jet by the
knownequationP=4•V2. e systolic pulmonary pressure, as already seen, is calculated
by adding to the value obtained from the equation above, the estimated pressure in the right
atrium (obtained by the size and kinetics of the vena cava).
However, an increase in right ventricular afterload does not always induce pulmonary hypertension. If the contractile function of the right ventricle is strongly depressed, a pseudonormal
pulmonary pressure can also arise, due to low cardiac output.
Conversely, high pulmonary pressures can be measured in the absence of an acute cor pulmonale, in the case of left/right shunt, pulmonary valve stenosis, constrictive pericarditis,
interstitial lung diseases etc.
A major problem is the differentiation between acute and subacute/chronic cor pulmonale.
is distinction is not based on a defined criterion, but it is influenced by the clinical setting
and by some echocardiographic aspects. When there is systolic overload of the right ventricle,
even if relatively recent, right ventricular hypertrophy is detected. It is possible to measure the
thickness of the free wall of the right ventricle through a subcostal diastolic scan. In normal
cases this thickness is 3.3 ± 0.6 mm. is measure can double only after 48 hours of increased
right afterload. In chronic pulmonary heart disease the thickness of the free wall of the right
ventricle may exceed 1 centimeter. Finally, the pulmonary systolic pressure reached in acute
conditions, does not exceed 60 mmHg.
Echocardiography 343
Figure 41 – Large regurgitant tricuspid jet (above). Below: Spectral Doppler signal recorded from
the same patient. According to the modified Bernoulli equation an atrioventricular pressure gradient is
calculated (around 40 mm/Hg). The systolic pulmonary pressure is calculated by adding to this value the
estimated pressure in the right atrium (obtained by the size and kinetics of the vena cava).
Figure 42 – Above: Physiologic regurgitant trucuspid jet in a normal subject. Below: Patient with
pulmonary hypertension. A high atrioventricular pressure gradient is detected by continuous Doppler
interrogation (more than 50 mm/Hg).
344 oracic ultrasound
➣ TAPSE (tricuspid annular plane systolic excursion)
It is an easily acquirable parameter that correlates with the right ventricular function (Fig. 43).
Figure 43 – TAPSE measurement in a normal subject. Apical four chambers scan. The M-mode cursor
is placed through the lateral tricuspid annulus and its movement is displayed in the time-motion graph.
It is measured on an apical four chambers scan, placing the M-mode cursor through the
tricuspid annulus in the lateral position, so that the annulus moves along the M-mode line
and it is possible to accurately measure its displacement. is displacement is evaluated from
the end-diastolic to the end-systolic phase, and it is considered normal if greater than 15 mm.
e lower the TAPSE and more depressed is the right ventricular pump function, the lower
the TAPSE and the higher the mortality.
➣ Thoracic aorta
Aortic diseases (aortic atherosclerosis, aortic aneurysm and aortic dissection) are an important
cause of cardiovascular morbidity and mortality. It is estimated that the annual incidence
of aortic dissection is between 5 and 30 cases per million. Many patients with acute aortic
syndrome die before reaching the hospital and before the event is detected34.
e diagnosis of acute aortic syndrome and aortic rupture is therefore not simple and requires
a high index of suspicion.
Ultrasound techniques for imaging of the aorta include transthoracic echocardiography
(TTE), transoesophageal echocardiography (TOE), abdominal ultrasound and intravascular
ultrasound (IVU).
Table 9 lists normal sizes of thoraco-abdominal aortic segments.
Table 9 – Normal sizes of aortic segments
Segment Size
Aorticannulus
SinusesofValsalva
Sinotubularjunction
Tubularascendingaorta
Aorticarch
Descendingaorta
Abdominalaorta
20-31mm(13±1mm/m2)
29-45mm(19±1mm/m2)
22-36mm(15±1mm/m2)
22-36mm(15±2mm/m2)
22-36mm
20-30mm
<30mm
Echocardiography 345
Clip 67 – Suprasternal scan. 58-year-old woman, hypertension, she arrives
in the ER with violent chest pain. Negative ECG. The clip shows ectasia of
the arch and the descending portion of the aorta, where echoes of doubtful
meaning are visualized in the lumen.
Clip 68 – Assessment of the patient of clip 67 with transesophageal echo.
The descending aorta, after the origin of the subclavian artery, is the site of
dissection with an extensive false anterior lumen (distal dissection).
e aorta and its major branches can be studied with different ultrasound scans. e ascending aorta is visualized with the parasternal scan. When the vessel is enlarged, right parasternal
and apical scans can also be used (Clips 69-71). e aortic arch can be displayed with the
suprasternal scan. e descending aorta may eventually appear in parasternal, apical or abdominal scans (Clips 72-73).
Clips 69-71 – Long axis parasternal scan. Aneurysmal dilatation of the
ascending aorta.
Clip 72 – Long axis parasternal scan. The left atrium is compressed by the
thoracic aorta, which is markedly ectasic.
Clip 73 – Apical 4 chambers scan. The left atrium is compressed by the
thoracic aorta, which is markedly ectasic.
Ultrasound detectable atherosclerotic plaques in the aorta indicates the presence of atherosclerotic disease and a possible source of systemic embolism. e suprasternal window may
be useful for detecting plaques in the aortic arch.
TTE is an excellent modality for imaging aortic root dilatation (annuloaortic ectasia, Marfan
syndrome, bicuspid aortic valve). It suffices in the assessment of proximal ascending aorta
when an adequate acoustic window exists. However TOE is clearly superior to TTE for assessing aneurysms located in the aortic arch and descending aorta. TTE is useful for detecting
a functional aortic regurgitation.
e diagnosis of aortic dissection can be made with similar accuracy using different imaging
technique such as TOE, computed tomography (CT) or magnetic resonance imaging (MRI).
Compared with CT and MRI, echocardiography has the advantage of being applicable in
emergency room, Intensive care or operating room.
e most used anatomical classification of aortic dissection is currently the Stanford one,
that divides dissections into proximal and distal. Proximal dissection (A type) involves the
346 oracic ultrasound
aorta in its ascending tract with possible extension downstream. Distal dissection (B type)
involves the aorta only in the downstream portion after the origin of the left subclavian artery.
e sensitivity and specificity of transthoracic echocardiography vary between 35% and
80% and between 39% and 96% respectively, according to the anatomic location. For this
reason, the sensitivity of TTE for detecting type B dissection is only 31-55%. e study of
the thoracic aorta is made difficult by technical problems such as the presence of pulmonary
emphysema, obesity or the narrowness of the intercostal spaces. Transthoracic echocardiography can not be considered a conclusive technique to exclude aortic dissection, even if
limited to the ascending limb.
False positives (3.5%) can be generated by the presence of artifacts within the dilated ascending aorta, and recent experiences demonstrate that the presence of an intraluminal linear
image in the ascending aorta alone should not be accepted as dissection criterion. In a dilated
ascending aorta, linear reverberation artifacts are very common (44-55%). e assessment
of location and movement of these intraluminal images is the best way for differentiating a
true flap from reverberation artifacts.
On the contrary, several studies have demonstrated the accuracy of TOE in the diagnosis of
aortic dissection with sensitivity of 86-100% and specificity 90-100%. e limit of TOE is
the strong dependence on the operator and it does not allow to assess the extent of dissection
downstream the thoracic aorta. Clips 67 and 68 exemplify the limitations of transthoracic
ultrasonography compared with the transesophageal approach.
e visualization of an intimal flap is the most characteristic finding of aortic dissection
(Clips 74-76). e study of the abdominal aorta can often show the presence of the double
lumen because of the extension of the dissection at this level (Fig. 44 and 46) (Clips 77-78).
Clip 74 – Characteristic intimal flap in the ascending portion of the thoracic
aorta.
Clip 75 – Characteristic intimal flap in the ascending portion of the thoracic
aorta, immediately above the valve plane.
Clip 76 – Characteristic intimal flap in the descending portion of the thoracic
aorta to the transesophageal examination.
Clip 77 – Transverse scan at the level of the subrenal abdominal aorta. It
shows the presence of double lumen in a case of distal aortic dissection.
Clip 78 – Longitudinal scan at the level of the suprarenal abdominal aorta.
It shows the presence of double lumen in a case of distal aortic dissection.
In cases of proximal dissection, even the study of carotid arteries sometimes documents the
extent of supraortic vessels dissection (Clip 79).
Echocardiography 347
Clip 79 – Longitudinal scan of the right carotid artery. Double lumen in a
case of proximal aortic dissection.
Figure 44 – Type 1 aortic dissection involving the entire aorta and the iliac arteries. CT scan.
Figure 45 illustrates a diagnostic strategy of acute aortic dissection.
Figure 45 – Diagnostic strategy of acute aortic dissection.
348 oracic ultrasound
DOUBLE LUMEN
Figure 46 – A: longitudinal scan. B: transverse scan of the abdominal aorta in a case of distal dissection
of the thoracic aorta: presence of double lumen.
DOUBLE LUMEN
➣ Infective endocarditis
Infective endocarditis is a frequently misunderstood rising disease. Sometimes critically ill
patients (e.g. subjects with acute pulmonary edema and/or septic shock) can come to the
observation of the emergency department, and the echocardiography can quickly orient to
the correct etiology. Otherwise, the presentation is more subtle, and the patient refers unexplained persistent fever, back pain secondary to spondylodiscitis, splenomegaly, and new
onset cardiac murmurs.
With ultrasound, endocarditis appears as hypo-or hyperechoic mobile valvular vegetations.
e infective vegetations can be seen on each flap valve or part of the valve apparatus, but
are tipically attached on the low pressure side of the valve. ey may appear on the mural
endocardium of the cardiac chambers or the ascending aorta. e vegetations generally do
not alter the movements of the valves except that, at times, preventing a correct closure and
generating valvular incompetency.
Destructive valve lesions are very frequently associated with vegetations or may be observed
alone. ey may provoke valve aneurysm, perforation or prolapse, and chordae or papillary
muscle rupture. Abscessess are more frequent in aortic and prosthetic valve endocarditis.
e execution of the transthoracic survey allows the diagnosis of endocarditis with variable
sensitivity between 30% and 100% and ultrasound appears to be more effective in the definition of vegetations greater than 3 mm and of those, generally voluminous, due to fungal
etiology
carditis. erefore, in no case the result of a negative transthoracic ultrasonography allows to
exclude the diagnosis of endocarditis (Clips 80-86).
36,37
. A negative echocardiogram may be observed in about 15% of infective endo-
Clip 80 – Apical 5 chambers scan. 65-year-old patient with low-grade
fever for a few months. He comes to the emergency department with acute
pulmonary edema. The clip shows the presence in diastole of two hyperechoic
highly mobile formations leading to prolapse of the aortic cusps in the outflow
tract of the left ventricle. Severe aortic insufficiency.
Echocardiography 349
Clip 81 – Apical 4 chambers scan. 85-year-old patient with a history of
high blood pressure and fever for ten days. Upon arrival at the emergency
department: mitral regurgitation murmur, not reported in a recent visit.
Floating vegetation adherent to the posterior mitral flap.
Clip 82 – Detail of the aortic valve in apical 5 chambers scan. 34-year-old
patient with a history of drug abuse, admitted to the ER with severe sepsis.
Hyperechoic irregular formation, attributable to endocarditis.
Clip 83 – Splenic ultrasonography of the previous case: massive abscess
formation.
Clip 84 – Apical 4 chambers scan. 70-year-old patient with pulmonary
edema and low-grade fever for two weeks. ECG: rapid atrial fibrillation.
The clip shows a coarse vegetation that affects the rear flap. Severe mitral
regurgitation.
Clip 85 – Detail of the mitral valve in apical 4 chambers scan. Mobile
endocarditis vegetation, adherent to the posterior mitral flap.
Clip 86 – Massive fungal vegetation of the tricuspid valve.
Conversely, false diagnosis of infective endocarditis may occur in several situations. For example, it may be difficult to differentiate between vegetations and thrombi, cardiac tumours,
prolapsed cusps, mixomatous changes or non infective vegetations (marantic endocarditis).
Fig. 47 is an algorithm proposed by the Task Force on the Prevention, Diagnosis and
Treatment of Infective Endocarditis illustrating the respective indications of Transthoracic
and Transesophageal Echocardiography (TTE and TEE). In all suspected cases, TTE must
be performed first. However TEE is important in the majority of patients with suspected
infective endocarditis, because of its better imaging quality and sensitivity38.
Соседние файлы в папке Библиотека им академика М.И. Перельмана