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H Ηχωκαρδιολογία στην καθηµερινή κλινική ιατρική πράξη
ΠΝΕΥΜΟΝΙΚΗ ΕΜΒΟΛΗ
Ε.Γ.ΔΑΛΑΜΑΓΚΑ ΚΑΡΔΙΟΛΟΓΟΣ
Διδάκτωρ Ιατρικής Σχολής ΑΠΘ
ΜΕΤΕΚΠΑΙΔΕΥΤΙΚΑ ΜΑΘΗΜΑΤΑ ΗΧΩΚΑΡΔΙΟΛΟΓΙΑΣ-ΑΠΕΙΚΟΝΙΣΗΣ ΚΕΒΕ 2013
Pulmonary embolism still a big challenge….
….in terms of diagnosis because of
its unspecified clinical characteristics.
Pulmonary embolism • Pulmonary embolism is a relative common cardiovascular
emergency. • By occluding the pulmonary arterial bed it may lead to acute
life-threatening but potentially reversible RV failure. • PE is a difficult diagnosis that may be missed because of non
specific clinical presentation. • However, early diagnosis is fundamental, since immediate
treatment is highly effective.
Pathophysiology • The consequences of acute PE are primarily hemodynamic and
become apparent when 30-50% of the pulmonary arterial bed is occluded by thromboemboli.
• Sudden death may occur, usually in the form of
electromechanical dissociation. • Or, the patient presents with syncope and/or systemic
hypotension, which might progress to shock and death due to acute RV failure.
• Rightward bulging of the IVS may further compromise the
cardiac output as a result of diastolic LV dysfunction. Eur Heart Journal 2008 (29), 2276-2315
Diagnosis • Chest Xray is usually abnormal and the most frequent findings
( plate-like atelecatsis, pleural effusion, or elevation of a hemidiaphragm) are non specific.
• But chest X ray is useful in excluding other causes of SOB and chest pain.
• PE is associated with hypoxaemia, but up to 20% of pts have normal PaO2 and a normal alveolar- arterial oxygen gradient (D(A-a)O2).
• ECG signs of RV strain, such as T wave inversion in V1-V4, a QR pattern in V1,the classic S1Q3T3 type and RBBB may be helpful.
• Normal D- dimer level renders acute PE or VTE unlikely,( the negative predictive value of D-dimer is high).
• Grade the level of evidence of diagnostic procedures • Clinical assessment : high risk / non high risk • Severity of PE ~ early mortality risk
Eur Heart Journal 2008 (29), 2276-2315
Eur Heart Journal 2008 (29), 2276-2315
Eur Heart Journal 2008 (29), 2276-2315
ECHO: Limited sensitivity 60-70% Eur Heart Journal 2008 (29), 2276-2315
Role of ECHO in “high risk” pulmonary embolism
• Differential Diagnosis -cardiogenic shock -acute valvular dysfunction -tamponade -aortic dissection
• Screen for right heart thrombi in transit • Detect indirect signs, which are highly suggestive of PE
Screen for right heart thrombi in transit Direct visualization of thrombus in PE
• Thrombus can form anywhere in the venous system and be visualized anywhere en route to the lungs-IVC,SVC,RA,RV,PA
• Thrombi visualized proximal to PA not diagnostic of PE, but point to the process
• DDX of thrombi: tumors, myxomas • Pulmonary arteries can be visualized to the bifurcation
Recognising normal right heart structures
• The moderator band
• Eustachian valve
• Chiari network
RV dysfunction Echo criteria for diagnosis of PE
• Acute RV dilatation Increased RV/LVEDD ratio • RV impairement (depressed contractility) Mc Connell sign • Raised pulmonary systolic pressure Increased TR velocity Decreased pulmonary acceleration time • Disturbed RV ejection pattern 60/60 sign • Pressure overload • Impaired myocardial performance RV MPI
The RV as a window to the pulmonary Vasculature: The healthy Right Ventricle
• The normal RV is accustomed to low pulmonary resistance • Normal right ventricular pressures are low and compliance is
high • Unlike the left ventricle, the normal right ventricle does a poor
job at acutely responding to sudden increases in afterload.
• PE results in an acute increase in pulmonary vascular resistance
• A previously normal RV is unable to accutely accommodate this additional load
• The RV dilates acutely, but cannot acutely increase pressure. • Depending on the size of the PE, this can result in mild right
ventricular dysfunction to frank right ventricular failure. • The RV that has been subject to increased load for grater
periods of time will hypertrophy and better handle the increased load.
The RV in Pulmonary Embolism
Pathophysiology of Acute PE
RV Afterload
RV Dilatation/ Dysfunction
RV Cardiac Output
LV preload
LV Output
RV ischemia/ infarction
Pulmonary Embolism
Pulmonary Resistance
RV Wall Tension
RV O2 Demand
Coronary Perfusion
Hypotension
RV O2 Supply
Am Heart J 1995,:130:1276-82
Review standart 2D right heart views
RV dilatation in PE
• Is the RV diameter greater than the LV diameter in the 4 chamber view?
• Normal RV diameter- 0.9-2.6 cm in 4C • Mean RV diameter in PE: >2.7cm • Series of 261pts with acute PE Mean RV EDD= 4.1cm, RV/LV ratio=0.9
PLAX, 4C
Relative RV: LV ratio 1:3 RV/LV EDD >0.55
EurHeartJ 1996
Quantification of RV size
Reference range RVIT 2.7-3.3cm RVSAX 2-2.8cm RVLAX 7.1-7.9cm RVAd 11-28 cm²
Clinical application • Practical?
• Reproducible?
Lang, JASE 2005
Moderate RV dilatation >o.6
Major RV dilatation ≥1
RV fractional area change
RVFAC= (RVAd-RVAs /RVAd) x 100
RVAd (cm²) 11-28 RVAs (cm²) 7.5-16
RV FAC % 32-60
-Good correl of RVFAC with RVEF from cMRI
-Utilized in numerous studies
-Feasible in clinical practice?
normal
TAPSE tricuspid annular plane systolic excursion
-Good correl of RVFAC with RVEF -simple -reproducable -but load dependant
Normal 1.6-2 Mild 1.1-1.5
Moderate 0.6-1 Severe <0.5cm
McConnell sign
Patients without previous / with known cardiorespiratory diseases • Sensitivity 77% • Specificity 94% • Positive predictive value 71% • Negative predictive value 96%
Distinct regional RV dysfunction
• Mid-free wall hypokinesia/akinesia • Normal apical motion
• Not seen in chronic PHT • But also seen in acute RV infarction
Am J Cardiol 1996
RV impairement (depressed contractility)
McConnell's sign : Mechanisms 1. In acute PE, the tethering of the right ventricular apex to a
contracting and often hyperdynamic left ventricle may account for the preserved wall motion at the apex.
2. The right ventricle may be assuming a more spherical shape to equalize regional wall stress when subjected to an abrupt increase in afterload.
3. There may be localized ischemia of the right ventricular
free wall as a result of increased wall stress.
RV systolic pressure
RVsyst pressure= 4 (TRVmax)²+estimated RAP
• RVSP PHT 35-55 mild 55-85 moderate >85 severe
60/60 sign TV PG<60mmHg
Tacc<60ms
98% specificity 48% sensitivity
Tacc normal>140ms Correlates with RVSP, MPAP,PVR
Pressure overload
Pressure loading systolic “D” shaped LV
Volume loading= diastolic D shaped LV+ TR/PR or L-R shunt ↑diastolic press= diastolic D shaped LV +RV impairement
Proposed echocardiographic measurements
• RV dimensions • RV fractional area change • Right atrial size and pressure • TAPSE • Eccentricity index • TEI index • TDI measurements of TV annulus • RV diastolic assessment • Presence of pericardial effusion • RV diastolic filling patterns
…concomitant echo signs of pressure overload are required To prevent the false diagnosis of acute PE in pts with RV free-wall
Hypo/akinesis due to RV infarction, which may mimic the McConnell sign.
RV overload criteria
• Presence of ≥1 of four signs: 1. Right sided cardiac thrombus 2. RV diastolic dimension (parasternal view) > 30mm,
or RV/LV ratio>1 3. Systolic flattening of the IVS 4. Acceleration time <90ms or TR>30mmHg σε
απουσία RVH
Prognostic significance of RV dysfunction
Acute Pressure Overload
RV dysfunction
Preexcisting CV
disease
Recurrent PE
Other serious comorbidity
(cancer)
Presence of a
PFO
Poor prognosis
Determinants of an adverse early outcome
• In patients with suspected high risk PE presenting with shock or hypotension, the absence of echocardiographic signs of RV overload or dysfunction practically excludes PE as a cause of hemodynamic instability.