**1.4.8 The diagnosis of DVT**

With duplex ultrasound the clot is visible as a hyperechogenic signal. The procedure has 95- 98% specificity. The sensitivity for PE is rather low, only 30-50% of PE cases present DVT with ultrasonography (Lee et al., 2005). The only validated verification method is the incomplete compressibility of the vein indicating the presence of the clot (Goldhaber & Morrison, 2002; Lee et al., 2005; Le Gal et al., 2006).

Although extremity CT can also aid the diagnosis of DVT, the increased irradiation, need of contrast agent and elevated costs contraindicate the use of CT scan in all cases (Brenner & Hall, 2007).

#### **1.4.9 Laboratory diagnostics**

*Arterial blood gas analysis:* Hypocapnia with hypoxaemia is characteristic for PE. About 20% of patients have a normal arterial oxygen tension and normal alveolar-arterial oxygen gradient (Rodger, Carrier, et al., 2000; Stein et al., 1996).

*D-dimer* is a fibrin degradation product. Quantitative ELISA or ELISA-like methods are 99% sensitive, if D-dimer concentration is above 500 µg/l. According to Dunn et al. the sensitivity for PE is 96.4%, with a negative predictive value of 99.6%, specificity 52.0% and positive predictive value 9.5%. Although the measurement is specific for fibrin, but the specificity of fibrin for VTE is considerably lower, the summarized specificity is only 40- 65%. The D-dimer test can be positive in the following diseases: infections, tumours, necrosis, pregnancy, postnatal, postoperative state, sepsis, etc., therefore, it cannot be used generally. In emergency situations, the D-dimer test is useful to exclude PE from differential diagnosis. Segal recommended the inclusion of D-dimer into the Geneva and Wells score systems (Dunn et al., 2002; Segal, Eng, et al., 2007; Spannagl et al., 2005; Reber et al., 2004; van Belle et al., 2006).

*Cardiac troponin T and B-type natriuretic peptide (BNP)*: Increased cardiac troponin and BNP levels are good indicators of impaired RV function. About 11-50% of PE patients show

chest pain, valve dysfunction, hypovolaemia). The sensitivity of echocardiography is about 60-70% in PE. Negative results do not exclude PE. Acute massive PE has characteristic echocardiography signs: RV hypokinesis and/or dilatation, the end diastolic diameter of the RV in the parasternal short axis > 30 mm, or RV/LV end diastolic diameter ratio > 0.9, in the apical or subcostal axis, D-sign, increased pulmonary arterial pressure, dilatation of the inferior caval vein. A heart cavity thrombus, patent foramen ovale (with the risk of paradox thrombi), tricuspidal valve thrombosis or vegetation and floating clot in the right ventricle

The positive echocardiographic result has a predictive value in haemodynamically stable patient, as the intermediate risk group has worse outcome (Konstantinides, 2008; Torbicki et al., 2003; Ferrari et al., 2005; Hsiao et al., 2006; Casazza et al., 2005; Bova et al., 2003; Miniati

The transoesophageal echocardiography is a semi-invasive diagnostic procedure, which can be useful in mechanically ventilated patients. Benefits of the transoesophageal approach are: visualisation of thrombi in the pulmonary trunk and/or main pulmonary arteries and also in the caval vein. Possible tumours originating from the heart or floating into the cavities of

With duplex ultrasound the clot is visible as a hyperechogenic signal. The procedure has 95- 98% specificity. The sensitivity for PE is rather low, only 30-50% of PE cases present DVT with ultrasonography (Lee et al., 2005). The only validated verification method is the incomplete compressibility of the vein indicating the presence of the clot (Goldhaber &

Although extremity CT can also aid the diagnosis of DVT, the increased irradiation, need of contrast agent and elevated costs contraindicate the use of CT scan in all cases (Brenner &

*Arterial blood gas analysis:* Hypocapnia with hypoxaemia is characteristic for PE. About 20% of patients have a normal arterial oxygen tension and normal alveolar-arterial oxygen

*D-dimer* is a fibrin degradation product. Quantitative ELISA or ELISA-like methods are 99% sensitive, if D-dimer concentration is above 500 µg/l. According to Dunn et al. the sensitivity for PE is 96.4%, with a negative predictive value of 99.6%, specificity 52.0% and positive predictive value 9.5%. Although the measurement is specific for fibrin, but the specificity of fibrin for VTE is considerably lower, the summarized specificity is only 40- 65%. The D-dimer test can be positive in the following diseases: infections, tumours, necrosis, pregnancy, postnatal, postoperative state, sepsis, etc., therefore, it cannot be used generally. In emergency situations, the D-dimer test is useful to exclude PE from differential diagnosis. Segal recommended the inclusion of D-dimer into the Geneva and Wells score systems (Dunn et al., 2002; Segal, Eng, et al., 2007; Spannagl et al., 2005; Reber et al., 2004;

*Cardiac troponin T and B-type natriuretic peptide (BNP)*: Increased cardiac troponin and BNP levels are good indicators of impaired RV function. About 11-50% of PE patients show

can also be visualised.

*Transoesophageal echocardiography* 

**1.4.8 The diagnosis of DVT** 

**1.4.9 Laboratory diagnostics** 

van Belle et al., 2006).

Hall, 2007).

et al., 2001; Roy et al., 2005; Konstantinides et al., 1998).

the heart can also be visualised (Sanchez et al., 2008).

Morrison, 2002; Lee et al., 2005; Le Gal et al., 2006).

gradient (Rodger, Carrier, et al., 2000; Stein et al., 1996).

increased marker levels. Echocardiography results correlate showing a decreased RV function. Negative troponin results are good predictors of favourable outcome. Both markers are useful and independent predictors of the 30 days mortality. Impaired RV function with increased troponin and BNP are relative indications of thrombolysis (TL) therapy in the intermediate risk group (Giannitsis et al., 2000; Kostrubiec et al., 2005; Krüger et al., 2004; ten Wolde et al., 2004; Worth, 2009). The recommended therapeutic approach according to Kucher and Goldhaber based on these data (Kucher & Goldhaber, 2003):

Fig. 2. Kucher and Goldhaber recommendation for the treatment of pulmonary embolism based on biomarkers and echocardiography.

Cases with severe haemodynamic shock present elevated lactate and metabolic acidosis due to global microcirculatory impairment and tissue hypoxaemia. These markers can predict poor outcome.

According to the recent guidelines, the diagnosis of PE is mainly based on the results of echocardiography, MDCT and biomarkers (Torbicki et al., 2008).
