One in every three patients with deep vein thrombosis (DVT) may have silent pulmonary embolism (PE), but its clinical relevance has not been thoroughly studied. Methods: We used the RIETE Registry data to compare the clinical characteristics, diagnostic tests, and 3-month outcome in 842 patients with proximal DVT in the lower limbs and silent PE at baseline, 1533 with DVT without PE, and 585 patients with DVT and symptomatic PE. Results: On admission, a minority of DVT patients (with or without silent PE) presented with hypoxemia (9.0% vs. 6.4%, respectively), or typical PE signs on the chest X-ray (25% vs. 22%) or electrocardiogram (23% vs. 17%). Patients with symptomatic PE more frequently presented with hypoxemia (30%) or had PE signs on the chest X-ray (41%) or electrocardiogram (37%). After the initial 15 days of follow up the incidence of PE was higher among patients with DVT and silent PE compared to those with symptomatic PE (0.95% vs. 0.17%).During the first 90 days of anticoagulant therapy, patients with DVT without PE had a lower incidence of recurrent PE than bleeding (1.0% and 2.9%, respectively). Of note, an excessive risk for bleeding was observed during the first 2 weeks of therapy among patients without PE. Incidence of recurrent PE and major bleeding was similar in DVT patients with silent PE (1.8% and 1.9%) and in those with symptomatic PE (2.6% and 2.7%). Conclusions: Most DVT patients with silent PE have no hypoxemia, chest X-ray signs or electrocardiographic evidence suggestive of embolism. Frequency of recurrent PE was higher among patients with silent PE at the initial 15 days of follow up. In contrast to other subgroups, in DVT patients without PE at baseline, the incidence of major bleeding far exceeded that of PE development during follow up.
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Asterisk with author names denotes non-ASH members.