Right ventricular function in pulmonary embolism
Abstract: Patients with pulmonary embolism (PE) and right ventricular (RV) dysfunction are known to be at risk of in-hospital clinical worsening and PE-related mortality. Even in patients with a preserved systemic arterial pressure, the RV dysfunction indicates a higher risk, thus affecting the patients’ level of care and the therapeutic approach. Involvement of the right ventricle is usually associated with at least a moderate degree of PE. The extent of the pulmonary vascular obstruction has been shown to be crucial for the increase in pulmonary vascular resistance and, thereby, for the prognosis of the patients. A substantially elevated D-dimer in clinically suspected patients is suggestive of PE and is associated with an adverse outcome. Echocardiography is frequently used to assess RV function in PE patients. The pulsed-wave Doppler tissue imagining (DTI) technique has been used to detect RV dysfunction in different clinical conditions and has been validated by several non-invasive techniques. The aim of these studies was to investigate the role of RV dysfunction detected by echocardiographic techniques in PE patients and to relate the findings to D-dimer levels, the extent of perfusion loss detected by pulmonary scintigraphy, and clinical prediction rules. Study I: By using tricuspid annular plane excursion, both systolic and diastolic RV functions were found to be impaired in the acute stage and, to an even higher degree, in association with an elevated RV systolic pressure. Diastolic function recovered earlier than systolic function. Study II: Using DTI technique, disturbed diastolic RV function was identified in patients with normal RV systolic pressure, normal RV systolic function and normal filling pressure. Study III: A cut-off value for the D-dimer level was found to identify patients with RV dysfunction. Patients with higher D-dimer levels also had higher pulmonary vascular resistance and RV systolic pressure. Study IV: Signs of RV dysfunction were detected even in patients with relatively small lung perfusion losses. Lung perfusion had good correlation with pulmonary vascular resistance. Conclusion: Non-high-risk PE patients show signs of disturbed RV function. Diastolic RV function seems to be affected earlier than systolic RV function, as detected by the DTI-derived tricuspid early diastolic velocity (Em), indicating that this parameter can be used to detect RV dysfunction even in patients with normal systolic RV pressure at presentation. Also, a certain Ddimer level and degree of lung perfusion loss may be useful in identifying non-high-risk PE patients who should be further investigated and monitored.
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