A simple and reliable computed tomographic measure for the evaluation of right ventricle remodelling in acute PE: right ventricle apical angle
Authors: Kultursay B , Erkus Y C , Ocal B E , Keskin B , Tokgoz H C , Hakgor A , Sekban A , Bulus C , Tanyeri S , Sirma D , Kulahcioglu S , Karagoz A , Tanboga I H , Ozdemir N , Kaymaz C 
Published: October 2024

Abstract

Background and aims
In patients with acute pulmonary embolism (PE), right ventricular (RV) dysfunction as assessed by computed tomography (CT) and /or echocardiography has been considered to predict in-hospital and 30-day outcomes. In this study we proposed a novel CT measure for RV function, the apical angle (α1) between the RV free wall and the interventricular septum (IVS), and for the left ventricle (LV) function, the apical angle (α2) between the LV free wall and the IVS. We aimed to evaluate the predictive value of these angles to determine clinical and hemodynamic severity and in-hospital mortality (IHM) in acute PE patients.

Methods
The study population comprised retrospectively evaluated 536 patients (age 59+-16.2 years, female 55.3 %) with acute PE in whom diagnostic work-up and risk-based treatments have been performed in accordance with currently available acute PE Guidelines. The severity of pulmonary arterial (PA) obstruction (Qanadli score) and RV/LV ratio were assessed on CT, and RV function and non-invasive estimation of pulmonary arterial systolic pressures (PASP) were evaluted with echocardiography. The α1 was defined as the angle between the line from tricuspid medial annulus to the RV apex and second line from tricuspid lateral annulus to the RV apex, whereas α2 was defined as the angle between the line from mitral medial annulus to the LV apex and second line from mitral lateral annulus to the LV apex.

Results
Anticoagulant treatment only and intravenous tissue plasminogen activator were noted in 49.6 % and 17.9 % of patients, respectively. Ultrasound-assisted thrombolysis and rheolytic thrombectomy were also used in 25% and 7.5 % of patients, respectively. The IHM rate was 5.9 %. The increase in α1 was associated with a decrease in TAPSE/PASP ratio, and an increase in PESI score and a higher risk status (p=0.047, p&lt;0.001, p=0.001 respectively), but α2 showed no relation to PE severity (p=0.78). The value of α1 in predicting in-hospital mortality was evaluated with a logistic regression analysis with a model including PESI score, RV/LV ratio and α1. PESI score and α1 significantly predicted IHM (p= &lt;0.001 and 0.027, respectively. OR for a1 1.15, CI 95%[1.06-1.27]), but RV/LV ratio did not. In the receiver operating curve (ROC) analysis for IHM prediction, the cut-off value of 1.168 for α1/α2 ratio [area under the curve (AUC): 0.721; sensitivity:76.92 % and specificity: 65.8 %] and the cut-off value of 32.47 for α1 ( AUC: 0.718 ; sensitivity: 84.67 % and specificity: 59.5 %) provided higher prediction compared with cut-off value of 1.29 for RV/LV ratio ( AUC : 0.604 ; sensitivity 76.9 % and specificity 45.87 %).

Conclusion
Either α1 or α1/α2 ratio evaluation on CT seems to represent a simple and reliable approach in the assessment of RV acute remodelling in response to thrombo-obstructive pressure burden and for prediction of outcome in patients with acute PE.Alpha 1 angle of different risk groupsROC curve