Cardiothoracic CT: one-stop-shop procedure? Impact on the management of acute pulmonary embolism

Abstract

In the treatment of pulmonary embolism (PE) two groups of patients are traditionally identified, namely the hemodynamically stable and instable groups. However, in the large group of normotensive patients with PE, there seems to be a subgroup of patients with an increased risk of an adverse outcome, which might benefit from more aggressive therapy than the current standard therapy with anticoagulants. Risk stratification is a commonly used method to define subgroups of patients with either a high or low risk of an adverse outcome. In this review the clinical parameters and biomarkers of myocardial injury and right ventricular dysfunction (RVD) that have been suggested to play an important role in the risk stratification of PE are described first. Secondly, the use of more direct imaging techniques like echocardiography and CT in the assessment of RVD are discussed, followed by a brief outline of new imaging techniques. Finally, two risk stratification models are proposed, combining the markers of RVD with cardiac biomarkers of ischemia to define whether patients should be admitted to the intensive care unit (ICU) and/or be given thrombolysis, admitted to the medical ward, or be safely treated at home with anticoagulant therapy.

Fig. 1

Pathophysiology of pulmonary embolism. Due to obstruction of the pulmonary vascular bed, increased vascular resistance, and increased RV afterload, PE can lead to RVD. RVD can have several consequences. First, it can decrease RV output. Second, RVD may result in a decrease of LV preload and output, caused by an increased RV volume and dilatation, eventually leading to decreased cardiac output. Finally, RVD can cause decreased coronary perfusion, leading to ischemia, which in turn results in a further increase of RVD. RV = right ventricle, PE = pulmonary embolism, RVD = right ventricular dysfunction, LV = left ventricle, PA = pulmonary artery

Fig. 2

CTPA of a 31-year-old female patient who was reanimated. The 1-mm axial reconstructions demonstrate bilateral central pulmonary emboli with dilatation of the main pulmonary artery (a) and massive right-sided cardiac dilatation with compression of the left ventricle (b). The patient died shortly after as a result of massive cerebral ischemia

Fig. 3

CTPA performed in a 22-year-old male patient complaining of progressive dyspnea and chest pain, revealing extensive pulmonary emboli including the main pulmonary artery with dilatation of the main pulmonary artery (a, diameter 33 mm) and the right side of the heart (b). The wedge-shaped subpleural consolidation (c) is caused by pulmonary infarction (d, pulmonary window setting). Because of the extensive load and the right ventricular dysfunction at CT, the patient was admitted to the ICU for thrombolytic treatment. The patient became hypotensive shortly after arrival but recovered quickly after treatment. The follow-up CTPA after 1 week shows clearance of thrombus from the main pulmonary artery with normalization of its diameter (e, diameter 25 mm) and normalization of the right ventricle. There is still extensive thrombus present on both sides

Fig. 4

The estimated prevalence and mortality of different risk factors in patients with pulmonary embolism (adapted from Becattini et al. 2008) [5]. RVD = right ventricular dysfunction, TnT = troponin T, BNP = brain natriuretic peptide

Fig. 5

a The clinical management of hemodynamically stable patients in pulmonary embolism. After establishing the diagnosis of PE, RV function should be determined, followed by the markers of myocardial injury. If there are signs of RVD and an elevation of troponin or fatty acid binding proteins, thrombolysis could be the next step. If there is only RVD or an elevation in the markers of myocardial injury, then the patient could be admitted to the medical ward. Outpatient treatment is the option in the absence of RVD or signs of myocardial injury. PE = pulmonary embolism, RV = right ventricle, RVD = right ventricular dysfunction, MDCT = multi detector computed tomography, BNP = brain natriuretic peptides, H-FABP’s = fatty acid binding proteins, ICU = intensive care unit. b After establishing the diagnosis of PE, the cardiac biomarkers are first taken into consideration. Outpatient treatment can only be considered if the cardiac biomarkers reveal no abnormalities. If these biomarkers are abnormal, RV function should be monitored. In case of RVD, only two options are left: admission to the medical ward in the absence of RVD or admission to ICU in combination with thrombolysis in the presence of RVD. PE = pulmonary embolism, BNP = brain natriuretic peptides, H-FABP’s = fatty acid binding proteins, RV = right ventricle, MDCT = multidetector computed tomography, ICU = intensive care unit