Long-Term Outcomes of Post-Surgical Deep-Vein Thrombosis in Asia: The AIDA-Extension Study.

Background: We have recently demonstrated in a large multinational, multiethnic study that the incidence of venographic deep-vein thrombosis (DVT) in Asian patients undergoing major orthopedic surgery of the lower limbs and not receiving thromboprophylaxis was similar to that observed in orthopedic patients in Western countries. Overall, 407 patients (20–99 years) undergoing THR (n=175), TKR (n=136) or HFS (n= 96) were recruited in 19 centres across Asia (Indonesia, South Korea, Malaysia, Philippines, Taiwan and Thailand). 72.5% of the enrolled patients had adequate venograms. Total DVT was diagnosed in 121 of 295 evaluable patients (41.0%, [95% confidence interval: 35.4–46.7]). Proximal DVT was found in 30 patients (10.2% [7.0–14.2]). However the long-term outcomes following deep vein thrombosis such as recurrence of DVT, incidence of pulmonary embolism (PE), and post-thrombotic syndrome (PTS) remain unknown. PTS has received little attention in the literature, and particularly in Asia.

Objectives: To assess the long-term complication rates (at 1 and 2 years) of patients with objectively assessed DVT compared to those observed in patients without post-operative DVT.

Methods: Annual visits were performed to record the occurrence of DVT/PE, incidence of PTS, cumulative incidence rates and related predictive factors. PTS scoring were assessed using the Villalta scale (signs and symptoms). In addition in a subset of 18 out of 27 (66%) patients from South Korea with centrally adjudicated venographic DVT, a second venogram was performed at 1 year in order to verify possible spontaneous modifications of the thrombus (none of these patients had undergone any anticoagulant treatment).

Results: From the 332 patients having completed the AIDA study in the 19 centres involved in the extension study, 236 patients (71.1%) agreed to participate in the extension phase and were assessed at year 1. Year 2 follow up visits were completed in May 2005. Complete data analysis of the final study results are ongoing and should be completed by September 2005. Of the 18 patients who underwent a second follow-up bilateral or unilateral ascending venography at 1 year ± 3 months post-operatively, 11 (61%) patients demonstrated resolution of the thrombus, with 3 (16%) patients showing incomplete resolution or persistence of the venous thrombosis. The venograms of the remaining four (23%) patients presented with development of collateral circulation confirming the progressive state of PTS. The majority of patients with centrally adjudicated venographic DVT demonstrated positive resolution following venographic assessment at year 1. The high incidence of thrombus resolution may have been due to the fact that most patients were diagnosed with distal DVT, which would suggest that a high percentage of DVT of the distal veins may resolve spontaneously compared to other types of DVT.