Residual Clot in Patients with Deep Vein Thrombosis and Pulmonary Embolism: Prognostic Implications

In order to assess whether there is discordance in the timing of thrombus resolution between deep vein thrombosis (DVT) and pulmonary embolism (PE), we analyzed current evidence from recent major literature, and evaluated its prognostic implications. After an episode of proximal DVT, residual vein thrombosis (RVT), as shown with ultrasonography, is still detectable in approximately 50% of patients after three months, and in lower proportions afterwards. RVT is likely to represent a marker of hypercoagulability, and is associated with an approximately doubled risk for recurrent thromboembolism, post-thrombotic syndrome, arterial thrombotic events and cancer. Males, individuals with extensive thrombosis and those with previous thromboembolism have the highest likelihood of developing RVT. Conversely, based on recent findings in 85% of patients with PE a full recanalization, as shown by CT scanning, is achieved, and in the remaining patients the thrombotic mass decreases by 80%. No association exists between residual embolism and the risk for recurrent thromboembolism or chronic thromboembolic pulmonary hypertension. Accordingly, repeating CT scanning for prognostic implications does not seem justified. These findings add to the growing perception that DVT and PE are to be regarded as separate pathophysiological entities.