Computed Tomographic Pulmonary Angiography in the Assessment of Severity of Acute Pulmonary Embolism and Right Ventricular Dysfunction

Abstract

Background: The distinction between severe pulmonary embolism (PE) and right heart dysfunction is important for predicting patient mortality. Purpose: To identify the role of computed tomographic pulmonary angiography (CTPA) in the assessment of the severity of acute PE and right ventricular dysfunction. Material and Methods: Eighty-five patients suspected of having PE, as diagnosed by CTPA and scintigraphy, were divided into three groups: hemodynamically unstable PE (HUPE) (n = 20), hemodynamically stable PE (HSPE) (n = 33), and no PE (n = 32). For each patient, obstruction scores, including short-axis diameters of the right ventricle (RV) and left ventricle (LV), main pulmonary artery, and superior vena cava (SVC), were measured. The RV/LV short-axis ratios were calculated. The shapes of the interventricular septum and the reflux of the contrast medium into the inferior vena cava (IVC) were evaluated. The mortality due to PE within a 1-month follow-up period was recorded. Results: The median CTPA obstruction score (HUPE 64%, HSPE 28%, P 0.001), median RV/LV short-axis ratio (HUPE 1.4, HSPE 1.0, P 0.01), median RV diameter (HUPE 55 mm, HSPE 42 mm, P 0.001), median SVC diameter (HUPE 23 mm, HSPE 19 mm, P 0.01), interventricular septum convex toward the LV (HUPE 70%, HSPE 18%, P 0.001), and reflux of the contrast medium into the IVC (HUPE 65%, HSPE 33%, p 0.05) were significantly different between the HUPE and HSPE groups. With ROC analysis, the CTPA obstruction score and RV/LV short-axis ratio threshold values for the HUPE patients were calculated to be 48% (95% sensitivity, 76% specificity) and 1.1 (85% sensitivity, 76% specificity), respectively. Three patients in the HUPE group died within the first 24 hours. Logistic regression methods revealed only the RV diameter as a significant predictor of death (odds ratio 1.24; 95% CI 1.04-1.48; P = 0.01). Conclusion: This study found that the parameters useful for distinguishing HUPE and HSPE included CTPA obstruction score, RV and SVC diameters, RV/LV short-axis ratio, interventricular septum shape, and reflux into the IVC. RV dilatation may be a significant predictor for mortality.