Contrast-enhanced multidetector computed tomography: a new prognosticator in acute pulmonary embolism?

We have read with interest the paper by Baptista et al., in which the authors propose that contrast-enhanced multidetector computed tomography (MDCT) may help assess prognosis in patients with intermediateto high-risk pulmonary embolism (PE).1 MDCT has traditionally been used for diagnostic purposes, but its potential role as a prognosticator in PE has been the subject of several studies in the last few years. Araoz et al. suggested that ventricular septal bowing was predictive of death due to PE, albeit with low sensitivity and high interobserver variability, while right ventricular (RV)/left ventricular (LV) diameter ratio and embolic burden were not associated with short-term death.2 Moreover, Van der Meer et al. assessed the predictive value of RV dysfunction and the pulmonary artery obstruction index (PAOI)3 for 3-month mortality following the initial diagnosis of PE, and concluded that both the RV/LV ratio and the obstruction index were significant risk factors for mortality, while no such relationship was found for the ratio of pulmonary artery to ascending aorta diameters or for the shape of the interventricular septum.4 On the other hand, Ghuysen et al. found no association between the PAOI and patient outcome, although right to left ventricular minor axis ratio, proximal superior vena cava diameter, azygos vein diameter and presence of contrast regurgitation into the inferior vena cava were shown to predict in-hospital mortality.5 A score was constructed by Ghanima et al. using the mean value of the largest affected vessel (sub-segmental =1, segmental =2, lobar =3, main pulmonary artery =4) in each lung. The score was shown to relate to the severity of PE as determined by blood oxygenation, biochemical and radiological parameters, and the authors proposed it could be of value for rapid risk stratification of PE.6 Furthermore, Rodrigues et al. tested the PAOI in their intermediateto high-risk PE cohort and concluded that a score above 18 was an independent predictor of RV 4