Stratifikace rizika akutní plicní embolie

Cor Vasa 2004, 45(8):379-383

Risk stratification of acute pulmonary embolism

Jiří Widimský: Klinika kardiologie, Institut klinické a experimentální medicíny, subkatedra kardiologie, IPVZ, Praha, Česká republika

Mortality of acute pulmonary embolism depends of the hemodynamic stability of patients. Hemodynamically unstable patients with hypotension, or those in cardiogenic shock, show increased mortality rates of 7% and 24.6%, respectively. Stratification of normotensive patients is a more challenging task. The group of normotensive patients at risk can be identified through detection of right ventricular dysfunction whose presence makes the prognosis of patients appreciably worse.
Recently, increases in cardiac troponins have been shown to be a marker of right ventricular dysfunction and acute pulmonary embolism severity even in patients free of coronary heart disease. According to some authors, a cTnT ³ 0.1 ng/ml is associated with mortality rates as high as 44%. Increases in cTnT and cTnI correlate with echocardiographically documented right ventricular dysfunction, ECG-documented right ventricular overload, and with arterial hypotension or other baseline clinical parameters. MAPPET 3 has implicated right ventricular dilatation, ECG signs of overload, and cardiac troponins as independent markers of a complicated course of acute pulmonary embolism. Increased cTnI and cTnT are yet another major marker allowing the identification of high-risk patients.
In addition, right ventricular dysfunction is associated with increases in BNP and pro-BNP. A pro-BNP below 50 pg/ml has a 97% negative predictive value and may indicate an uneventful favorable course. Future studies are warranted to determine the value of BNP.
In conclusion, troponin determination should also be made part of the process of clinical diagnosis on admission of hemodynamically stable patients with acute pulmonary embolism. Patients with increased troponin levels should undergo echocardiography. Patients with increased troponin levels and right ventricular dysfunction make a group at significantly increased risk. The basic question remains to be answered: should all patients with increased troponin levels and right ventricular dysfunction be treated by thrombolysis? There is a clear need for a randomized prospective study in this respect. As it is, an individualized therapeutic regimen considering the potential benefits and risk of thrombolytic therapy is necessary.