Normal ventricular diameter ratio on CT provides adequate assessment for critical right ventricular strain among patients with acute pulmonary embolism.

There is variability in guideline recommendations for assessment of the right ventricle (RV) with imaging as prognostic information after acute pulmonary embolism (PE). The objective of this study is to identify a clinical scenario for which normal CT-derived right-to-left ventricular (RV/LV) ratio is sufficient to exclude RV strain or PE-related short-term death. This retrospective cohort study included 579 consecutive subjects (08/2003-03/2010) diagnosed with acute PE with normal CT-RV/LV ratio (<0.9), 236 of whom received subsequent echocardiography. To identify a clinical scenario for which CT-RV/LV ratio was considered sufficient to exclude RV strain or PE-related short-term death, a multivariable logistic model was created to detect factors related to subjects for whom subsequent echocardiography detected RV strain or those who did not receive echocardiography and died of PE within 14 days (n = 55). The final model included five variables (c-statistic = 0.758, over-fitting bias = 2.52 %): congestive heart failure (adjusted odds ratio, OR 4.32, 95 % confidence interval, CI 1.88-9.92), RV diameter on CT >45 mm (OR 3.07, 95 % CI 1.56-6.03), age >60 years (OR 2.59, 95 % CI 1.41-4.77), central embolus (OR 1.96, 95 % CI 1.01-3.79), and stage-IV cancer (OR 1.94, 95 % CI 0.99-3.78). If these five factors were all absent (37.1 % of the population), the probability that "CT-RV/LV ratio is sufficient to exclude RV strain/PE-related short-term death" was 0.97 (95 % CI = 0.95-0.99). Normal CT-RV/LV ratio plus readily obtained five clinical predictors were adequate to exclude RV strain or PE-related short-term mortality.