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DIAGNOSTIC ALGORITHMS

DIAGNOSTIC ALGORITHMS. Doç. Dr. Güngör ÇAMSARI Yedikule Teaching Hospital for Chest Diseases and Thoracic Surgery, Istanbul. Venous Thromboembolism (VTE). Deep vein thrombosis (DVT) and pulmonary embolism (PE) are both part of one entity: VTE

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DIAGNOSTIC ALGORITHMS

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  1. DIAGNOSTIC ALGORITHMS Doç. Dr. Güngör ÇAMSARI Yedikule Teaching Hospital for Chest Diseases and Thoracic Surgery, Istanbul

  2. Venous Thromboembolism (VTE) • Deep vein thrombosis (DVT) and pulmonary embolism (PE) are both part of one entity: VTE • The annual incidence is for DVT and PE 1/1000 and 0,5/1000 respectively in general population of the Western World and rises with age (1/100 population at 85 years).

  3. Mortality in untreated patients %30 • Mortality in treated patients %2-8 • PE prevelance in hospitalized patients %12-15

  4. Diagnostic Problems • The clinical signs and symptoms are nonspesific • Decision of PE diagnosis and treatment with scintigraphy is possible in only 40% of patients • Pulmonary angiography (gold standart) is invasive, expensive and can cause cardiopulmonary complications

  5. Targets of Diagnostic Strategies - Noninvasive methods, which can decrease the need of pulmonary angiography, should be the choice - Cost-effectiveness • Suitable for local conditions • Variability in different clinical conditions

  6. Symptoms and Signs • Sensitive, but not very spesific • The presence of more than 1 clinical sign or symptom increases sensitivity • Most common symptoms are dyspnea and pleuritic chest pain • Most common signs are tachypnea (>20/min) and tachycardia (>100/min)

  7. Symptoms Dyspnea (80%) Pleuritic chest pain (52%) Pain or edema in legs Hemoptysis Palpitation Anginal chest pain Syncope/presyncope Signs Tachypnea (>20/min) (70%) Tachycardia (>100/min) (26%) Crackles Signs of DVT Temperature >38 oC Right gallop rhythm

  8. Surgery Trauma Immobilisation ( medical illness, hospitalisation) Paralitic lower limb Previous VTE history Malignancy+chemoterapy Anesthesia Central venous catheters Genetic factors Pregnancy, puerperium Obesity Long distance travel Advanced age Antiphospholipid syndrome Superficial venous trombosis Oral contraceptives, hormon replacement therapy Other (polycythemia vera, thrombocytosis, Behçet d.) Risk Factors

  9. First-line Diagnostic Tests - Chest x-ray, ECG and arteriel blood gases are first line tests - 80% of patients with PE and no cardiopulmonary disease have an abnormal chest radiograph but this is also nonspesific - ECG, is useful for ruling out other processes and for detecting and evaluating signs (50%) of right ventricular overload but it is also nonspesific

  10. Chest X-Ray ECG -Normal - Normal -Subsegmental atelectasis - Sinusal tachycardia -Small pleural effusions - Right ventricular overload -Pleural-based opacities - Precordial T wave invertion -Elevated hemidiafragm - Right bundle branch block -Cardiovascular pathologies - S1 Q3 T3 pattern

  11. Arterial Blood Gases • Arterial hypoxemia and respiratory alkalosis are common • In the PIOPED and PISAPED studies, over 80% of patients presented basal PaO2 <80 mmHg and hypocapnia • PaO2 < 80 mmHg; • sensitivity: 57%, spesificity:53% • Hypoxemia is related on age, alveolo-arterial gradient is increased

  12. Assessment of Clinical Probability Symptoms and signs + Risk factors + First line diagnostic tests Clinical Probability (low, moderate, high)

  13. Wells Scale • PE, most likely diagnosis : 3 point • Signs of DVT : 3 point • Previous DVT or PE : 1,5 point • Heart rate > 100 beats/min : 1,5 point • Immobilization or surgery (pre. 4 w) : 1,5 point • Cancer treated in the prior 6 month : 1 point • Hemoptysis : 1 point Clinical probability <2: low, 2-6: moderate, >6 high Ann Intern Med 1998;129:997

  14. Geneva Rules (Wicki ) • Recent surgery : 3 point • Previous DVT or PE : 2 point • PaO2: < 48.7 mmHg : 4 point 48.7-60 mmHg : 3 point 60-71.2 mmHg : 2 point 71.3–82.4 mmHg : 1 point • PaCO2: < 36 mmHg : 2 point 36-38.9 mm Hg : 1 point • Age: > 80 : 2 point 60-79 : 1 point • Pulse rate : > 100 beats/min : 1 point • Radiologic patology: • atelectasis : 1 point • elevation of hemidiafragm: 1 point Clinical probability 0-4: low, 5-8 moderate, > 9 high Arch Intern Med 2001;161:92

  15. Le Gal Scale • Age >65 : 1 point • Previous DVT or PE : 3 point • Surgery (during the previous 1 mo) : 2 point • Active malignant condition : 2 point • Unilateral lower limb pain : 3 point • Hemoptysis : 2 point • Heart rate 75-94 : 3 point • >95 : 5 point • Pain on leg palpation or edema : 4 point Clinical probability 0-3: low, 4-10: moderate, >11: high Ann Intern Med 2006;144:165

  16. Prevelance of PE according to Clinical Probability

  17. Clinical Probability • Evaluation of clinical probability is not sufficient for diagnosis and decision of treatment in PE • Clinical probability should be evaluated together withD-dimer, scintigraphy, spiral CT, lower limb compression ultrasonography for diagnosis

  18. D-Dimer • D-Dimer is a specific product of fibrin degradation • Highly sensitive markers for VTE but spesificity is low (in outpatients 40%) • The level of D-Dimer increases in infectious diseases, pregnancy, cancer, trauma, surgery, stroke, myocard infarction • D-Dimer is useful for excluding VTE with low clinical probability (in outpatients) • In hospitalized and old patients is not useful

  19. D-Dimer Measurement Techniques • ELISA techniques or turbidimetrics are the most sensitive quantitative techniques When ELISA tecniques used <500ng/ml D-Dimer excludes VTE 95-99% • Red cell agglutination (SimpliRED), latex agglutination, immunochromatography or immunonfiltration are more subjective qualitative tests

  20. Low clinical probability: (-) D-Dimer tests reliably excludes VTE • Intermediate clinical probability: (-) D-Dimer (only with ELISA tecniques) excludes VTE • High clinical probability: D-Dimer should not be used. It doesn’t exclude VTE (negative predictive value <80%)

  21. Scintigraphy • Lung scintigraphy should be performed within 24 hours of the onset of symptoms in patients with suspected PE • Perfusion scintigraphy is sensitive but specifity is low • If ventilation scan couldn’t be performed, perfusion scan should be assessed with chest x-ray

  22. Anormal perfusion scintigraphy rules out PE (negative predictive value 99%) • High-probability scintigraphy, is false positive in 15% of patients with suspected PE • PE prevelance is 25% with low or intermediate (non-diagnostic) perfusion scintigraphy

  23. PIOPED: Clinical probability assessment and V/Q scintigraphy

  24. PE can’t be diagnosed or ruled out in non- diagnostic scintigraphy patterns or a high probability scintigraphy and lower clinical probability (these patterns are seen in 60% of patients)

  25. Scintigraphic Patterns of High Probability for Pulmoner Embolism • According to PIOPED study : • 2 or more large segmental perfusion defects (>% 75 of a segment) without corresponding abnormalities in ventilation or chest radiograph, or defect substantially larger than 75% • 2 or more mismatched moderate segmental perfusion defects (% 25-75 of a segment) and 1 large segmental defect • At least 4 moderate defects without abnormalities in ventilation or chest radiograph.

  26. Problems in Scintigraphic Assessment • There is no agreed consistent terminology for reporting • Intraobserver disagreement or interobserver disagreement 10-20% • Ventilation Scintigraphy increases specifity and but also cost

  27. Spiral CT Angiography • Spiral CTA was developed during the early 1990s • Sensitivity and specificity are low in subsegmental arteries (6-22% of patients) • In prospective studies comparing CTA with lung scintigrapy, it was found that CTA had a substantially higher level of interobserver agreement and greater specifity • In many cases it provides an alternative diagnosis • CTA is currently available in most hospital

  28. Accuracy of diagnostic tests for PE

  29. Search for Deep Venous Thrombosis Contrastvenography: • Gold standart for DVT diagnosis • Limitations: • Expensive and invasive procedure • Allergic reactions and phlebitis may develop • Experimentation is necessary for interpretation • Wrong interpretation is frequent in massive thrombus

  30. Contrast venography Clinical probability of DVT high and noninvasive tests are nondiagnostic or impossible to perform Before VCI filters were inserted contrast venography should be done

  31. Compression Ultrasound • Most used noninvasive test for detecting DVT • In symptomatic acute proximal thrombosis sensitivity 97%, specificity 98% • Sensitivity 38% in asymptomatic cases • In symptomatic and DVT suspicious cases a negative examination doesn’t reliably exclude DVT (serial US must be done)

  32. Compression Ultrasound • In patients with co-existing clinical DVT, leg ultrasound as the initial imaging test is often sufficient to confirm VTE • A single normal leg ultrasound is not reliable for exclusion of subclinical DVT

  33. CT venography • Sensitivity and specificity in small case series are over 95% in the femoropopliteal region • Gonadal radiation risk is high • More studies are needed

  34. Magnetic Resonance Imaging • Sensitivity and specificity for PE were high in studies of a small number of cases • An alternative to CTA in patients with renal failure or allergy to contrast agents • It is useful for detecting DVT in venous areas that are hard to study, such as the pelvis or the VCI

  35. DIAGNOSIS OF DVT (ATS 1999) Suspected Acute DVT Compression US Normal Inconclusive DVT (+) or Seri US Inadequate study Treat (+) (-) venography or MRI Treat DVT(-) DVT(+)

  36. Echocardiography • It is used as a severity marker to detect RV dysfunction • It can identify intracardiac and main pulmonary artery thrombi • In the cases who have right ventricul overloading sensitivity 80%, specificity 97% • It is useful to guide urgent therapeutic decisions like • It is useful in differential diagnosis (MI, aorta dissection etc.)

  37. MASİF PE / EKOKARDİYOGRAFİ Sağ ventrikülde dilatasyon ve hipokinezisi Transözofagiyal Ekokardiyografi !

  38. Pulmonary Angiography • Gold standart test • Morbidity is 0.2%, mortality is 0.5% • Interobserver agreement in interpretation of subsegmental arteries is poor • DSA and generalized use of non-ionic contrast materials have minimized risks

  39. Diagnostic Strategies Capable of Excluding the Diagnosis of PE Clinical Probability Low Moderate High (-) D-dimer (-) D-dimer (ELISA) Normal V/Q scan Normal V/Q scan Normal V/Q scan (-) Pulmonary angiography (-) CT angiography + (-) DUS (-) CT angiography + (-) DUS Non-diagnostic V/Q scan + (-) serial DUS Non-diagnostic V/Q scan + (-) serial DUS (-) Pulmonary angiography (-) Pulmonary angiography

  40. Diagnostic Strategies Capable of Confirming the Diagnosis of PE Clinical Probability Low Moderate High (+) CT Angiography (+) CT Angiografi (+) CT Angiography (+) Pulmonary Angiography (+) Pulmonary Angiography (+) Pulmonary Angiography (+) DUS (+) DUS (+) DUS High probability V/Q scan High probability V/Q scan

  41. Diagnostic Algorithms for Hemodynamically Stable PE 1. Round: Torule out the diagnosis of PE • D-dimer and clinical probability is used • (-) D-Dimer + low clinical probability: PE excluded • (-) D-Dimer (ELISA) + intermediate clinical probability: PE excluded • CT Angiography or Lung scintigraphy as the initial test • CTA is not cost-effective as a first line diagnostic test • Scintigraphy resuls are only normal in a small minority of cases (fewer than 20%)

  42. Diagnostic Algorithms for Hemodynamically Stable PE 2. Round: To confirm the diagnosis of PE using noninvasive diagnostic tests • Scintigraphy, CT Angiography or Ultrasound will be the first choice for this purpose • In recent years, CTA and US are accepted

  43. If; • facilities are available on site • chest radiograph is normal • no co-existing cardiopulmonary disease is present • standardised reporting criteria are used SCINTIGRAPHY may be considered as the initial imaging investigation

  44. Diagnostic Algorithms for Hemodynamically Stable PE 3. Round: Gold standart tests (Pulmonary angiograpy and contrast venography) • P. angiography is indicated when high clinical probability + inconclusive diagnostic test results are present (especially in patients at risk for hemorrhage) • Venography is used only to avoid P.angiograhy

  45. Clinical Probability Low High Intermediate D-Dimer (ELISA or other methods) D-Dimer (ELISA) (-) (+) (-) (+) Lung scan or Spiral CT Normal High probability Non diagnostic (-) (+) US Clinical Probability Low Intermediate High Exclude pulmonary embolism Angiography

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