Our study has potential limitations. First, due to the low number of deaths (9 and 15 patients after 30 and 90 days, respectively) only a minimal adjustment and no analysis of the association between the CTOI and 30-day mortality could be performed. Second, our study might be underpowered to detect an association between the CTOI or RV/LV diameter ratio and all-cause mortality. Third, we enrolled exclusively patients aged 65 years or older with acute VTE. We thus cannot extrapolate our results to younger patients. Fourth, the fact that patients with a higher CTOI were more likely to receive thrombolytic therapy might have biased the results. However, when we excluded thrombolyzed patients in a sensitivity analysis, our results remained unchanged. Finally, we could not analyze the interobserver agreement for the CTOI assessment, because disagreement was immediately resolved by consensus and only the final CTOI value was available in our database.