In our prospective cohort of elderly patients with acute symptomatic PE, the CTOI was not associated with all-cause mortality, but with PE-related mortality at 90 days. Neither all-cause nor PE-related mortality differed significantly across the three pre-specified CTOI strata. The discriminative power of the CTOI for predicting PE-related 90-day mortality was moderate (C-statistics 0.69). In contrast, the RV/LV diameter ratio was neither associated with overall nor PE-related 90-day mortality.