Self-expanding metal stents for palliative treatment of superior vena caval syndrome.

Purpose: Two stent types (a new Wallstent and a Z-stent) were investigated in 30 patients with recurrent malignant superior vena caval syndrome (SVCS).
Methods: Eligibility requirements were that the patient had recurrent symptoms after appropriate radiation therapy, chemotherapy, or both; >/= 75% of the vessel was occluded; and there was collateral flow. Because of the limited availability of stents, it was not possible to perform a prospectively randomized study.
Results: In the Z-stent group (17 patients), occlusion of the stent due to acute thrombosis occurred within 12 hr in 4 patients (24%), but in the other 13 patients (76%) symptoms disappeared completely. After 2 weeks the cavogram in these patients showed no signs of thrombosis, and 12 (61%) of the patients remained symptom-free. There was partial occlusion in 5 patients (29%), without relevant clinical symptoms. Of the 13 patients who received Wallstents, only 1 had an acute immediate thrombosis (8%). Symptoms disappeared completely in the other 12 patients and no signs of thrombosis were seen. However, after 2 weeks complete stent occlusion with SVCS was found in 3 patients (23%) and partial occlusion with minor clinical symptoms in 6 (46%). Only 3 patients (23%) had complete relief of the SVCS. The difference between the rates of occlusion of the two stents after 2 weeks was highly significant (p = 0.008).
Conclusions: The overall clinical success rate for long-term patency was 100% for the Z-stents and 69% for the new Wallstent. These results suggest that when used for this purpose, the new Wallstent is more thrombogenic at 2 weeks than the Z-stent.