Patients after treatment for saphenous reflux, by whatever method, can develop a thrombus at the site of treatment. This may extend proximally into the common femoral vein or popliteal vein. In rare cases, it may occlude the deep vein like a DVT. Whilst the early stages of the process are usually symptomless, terminating and resolving within a few weeks, an occlusive thrombus will cause symptoms of leg swelling and discomfort. The mechanism of resolution is not known. The thrombus can detach into the venous circulation or “dissolve” in-situ. The term endovenous heat induced thrombosis (EHIT) classifies this condition. However, some limitations to EHIT have been identified with a proposal for a more comprehensive scoring system, which can be extended beyond the scope of post-ablation thrombosis.
FAUSTO PASSARIELLO The term post ablation superficial thrombosis extension (PASTE) describes the thrombotic evolution of the venous stump after endovenous ablation (EVA). This has been revised into a local and global score, termed eXtended PASTE (X-PASTE). The local part is shown in the table below. The score is from 0-9. It improves on EHIT by classifying the thrombus extension using two adjacent venous segments, the focus segment and the next downstream (proximal) segment. The global part describes a succession of segment couples, with a score for each segment, separated by a comma.
When the focus is occluded, values from 1 to 4 overlap perfectly the scores of EHIT in the saphenous-femoral junction. For example a score of 2 describes the situation where there is obstruction of <50% diameter with thrombus above an occluded focus. A score of 5 accounts for a floating thrombus in the next, i.e. the downstream segment above an occlusion. Scores from 6 to 9 describe the same thrombus extension when the focus or upstream (distal) segment is patent (or only partially occluded).
The X-PASTE scoring system has a clear advantage over EHIT because it is able to describe most of the appearances seen after EVA. For example, the goal of EVA procedures of closure up to the superficial epigastric vein has no code in EHIT, while it is assigned a score of 0,1 in X-PASTE. Furthermore, a floating thrombus in the common femoral vein has no code in EHIT, while it is assigned a score of 5 or 9 in X-PASTE, according to the state of the upstream saphenous arch segment, occlusion or patency, respectively. If the floating thrombus is located instead in the saphenous-femoral junction it is assigned a score of 0,5 or 0,9 in X-PASTE.
Thrombus resolution, progression or detachment may depend on whether this thrombus is in contact with the streaming blood which is why the patency of the upstream segment is described in X-PASTE.
The X-PASTE local scoring system
Floating thrombus at the sapheno-femoral junction above a patent GSV segment (X-PASTE score 0,9).