Prognostic Significance of Concomitant Superficial Vein Thrombosis in Patients with Deep Vein Thrombosis of the Lower Limbs

Background The prognostic significance of concomitant superficial vein thrombosis (SVT) in patients with lower-limb deep vein thrombosis (DVT) has not been consistently evaluated. Methods We used the RIETE (Registro Informatizado de Enfermedad TromboEmbolica) registry to compare the rates of subsequent pulmonary embolism (PE), recurrent DVT, major bleeding or death in patients with lower-limb DVT, according to the presence or absence of concomitant SVT. Results From March 2015 to May 2020, there were 8,743 patients with lower-limb DVT. Of these, 745 (8.5%) had concomitant SVT. Most patients (97.4% in both subgroups) received anticoagulant therapy (median duration: 138 vs. 147 days). During follow-up (median: 193 vs. 210 days), 156 (1.8%) patients developed subsequent PE, 336 (3.8%) had recurrent DVT, 201 (2.3%) had major bleeding and 844 (9.7%) died. Patients with concomitant SVT had a higher rate of subsequent PE (rate ratio [RR]: 2.11; 95% confidence interval [95%CI]: 1.33-3.24) than those with isolated DVT, with no significant differences in the rates of recurrent DVT (RR: 0.80; 95%CI: 0.50-1.21), major bleeding (RR: 0.77; 95%CI: 0.41-1.33) or death (RR: 0.81; 95%CI: 0.61-1.06). On multivariable analysis, patients with DVT and SVT concomitantly were at increased risk of subsequent PE during anticoagulation (adjusted hazard ratio [HR]: 2.23; 95%CI: 1.22-4.05) and also during the entire follow-up period (adjusted HR: 2.33; 95%CI: 1.49-3.66). Conclusion Patients with lower-limb DVT and SVT concomitantly are at increased risk of developing PE. Further studies are needed to externally validate our findings and to determine if these patients could benefit from a different management strategy.