Left atrium volume and ventricular volume ratio algorithm as indication of pulmonary hypertension etiology

Abstract

Background Pressure overload of the right heart (pulmonary hypertension [PH]) can be an acute or a chronic process with various pathophysiologic changes affecting the dimensions of the heart chambers. The automatic four-chamber volumetric analysis tool is now available to measure the volume of the cardiac chambers in patients undergoing a computed tomography pulmonary angiogram (CTPA). Purpose To characterize the volumetric changes that occurred in response to increased systolic pulmonary arterial pressures (sPAP) in acute events, such as acute pulmonary embolism (APE), compared with other etiologies. Material and Methods Consecutive patients who underwent CTPA and echocardiography within 24 h between 2011 and 2015 were included. Differences in cardiac chamber volumes were investigated in correlation to the patients’ sPAP. Results The final cohort of 961 patients included 221 (23%) patients diagnosed with APE. The right (RV) to left (LV) ventricular volume ratio (VVR) was higher, while the left atrial (LA) volume index was smaller ( P < 0.001) in the patients with APE. A decision tree for the prediction of APE showed that an RV to left VVR >2.8 was characteristic of APE, whereas an LA volume index >37.5 mL/m² was more compatible with PH due to other etiologies ( P < 0.001). Conclusion The combination of VVR and LA volume index may help in differentiating between APE and chronic PH. CTPA-based volumetric information may be used to help clarify the underlying etiology of the dyspnea.