LAUSR

Background: Isolated distal deep vein thrombosis (IDDVT) is a common form of venous thromboembolism (VTE). Limited data exist about the clinical characteristics, initial treatment, and short-term outcomes of these patients. Methods: Using the data from the RIETE registry (05/2001-02/2019), we identified patients with IDDVT without pulmonary embolism (PE). We determined the clinical presentation, initial treatment, and 30-day and 90-day outcomes. We compared the findings with patients with proximal DVT without PE. Results: We identified 5,359 patients with IDDVT (mean age 61±17 years, 50% women). The most prevalent comorbidities were hypertension (39%), anemia (28%), prior VTE (14%), active cancer (12%), heart failure (6.7%), and diabetes (6.6%). Recent surgery was reported in 16%. Most participants received anticoagulation (99%), most commonly with low-molecular-weight heparin (88%). No patient received thrombolytics and use of vena cava filters was rare (0.4%). At 30 days, 59 patients (1.1% [99% CI, 0.8%-1.5%]) died, including only 3 from PE (0.1% [99% CI, 0.01%-0.2%]), 44 (0.8% [99% CI, 0.5%-1.2%]) had nonfatal VTE recurrence, and 31 (0.6% [99% CI, 0.4%-0.9%]) had major bleeding. At 90 days, 2.9% (99% CI, 2.4%-3.6%) died (no additional death from PE), 1.5% (99% CI, 1.1%-2.0%) had nonfatal VTE recurrence, and 0.9% (99% CI, 0.6%-1.3%) had major bleeding. When compared with 25,420 individuals with proximal DVT without PE, those with IDDVT had lower co-morbidity burden including diabetes, heart failure, and cancer, but were more likely to have had recent surgery (P<0.001 for all). Patients with IDDVT also had lower odds of 30-day and 90-day death and major bleeding in bivariate and multivariable analyses (Figure). Conclusions: In a large multinational study, IDDVT occurred in patients with low comorbidity burden. Most patients with IDDVT received anticoagulation. Fatal PE was rare, and patients had a more benign prognosis compared with those with proximal DVT.