Optimized definition of right ventricular dysfunction on computed tomography for risk stratification of pulmonary embolism.

Objectives: There is an ongoing discussion on the optimal right to left (RV/LV) diameter ratio threshold and the best definition of RV dysfunction on computed tomography pulmonary angiography (CTPA) for risk assessment of pulmonary embolism (PE).

Methods: On routine diagnostic CTPA, volumetric and diameter measurements (axial and reconstructed views) of the ventricles and reflux of contrast medium into the inferior vena cava (IVC) and hepatic veins were assessed in consecutive PE patients enrolled in a prospective single-center registry. In-hospital adverse outcome was defined as PE-related death, cardiopulmonary resuscitation, mechanical ventilation or catecholamine administration.

Results: Of 609 patients (median age, 69 [IQR, 56-77] years; 47 % male) included in the analysis, 68 patients (11.2 %) had an adverse outcome and 35 (5.7 %) died. While neither a RV/LV volume ratio ≥1.0 nor RV/LV diameter ratios ≥1.0 were able to predict an adverse outcome, higher thresholds increased specificity. Further, neither volumetric measurements nor reconstruction of images provided superior prognostic information compared to RV/LV ratios measured in axial planes. The combination of an axial RV/LV diameter ratio ≥1.5 with substantial reflux of contrast medium was present in 134 patients (22 %) and associated with the best prognostic performance to predict an adverse outcome in unselected (OR 3.7 [95 % CI, 2.0-6.6]) and normotensive (OR 2.8 [95 % CI, 1.1-6.7]) patients.

Conclusion: A new definition of RV dysfunction (axial RV/LV diameter ratio ≥1.5 and substantial reflux of contrast medium to the IVC and hepatic veins) allows an optimized CTPA-based prediction of PE-related adverse outcome.