Physiologic Effect of Stent Therapy for Inferior Vena Cava Obstruction Due to Malignant Liver Tumor

Purpose To understand systemic the influence of stent therapy for inferior vena cava (IVC) obstruction due to advanced liver tumor. Methods Seven patients with symptomatic IVC obstruction due to advanced primary (n = 4) or secondary (n = 3) liver tumor were subjected to stent therapy. Enrollment criteria included high IVC pressure over 15 mmHg and the presence of edema and ascites. Z-stents were deployed using coaxial sheath technique via femoral venous puncture. Physiologic and hematobiochemical parameters were analyzed. Results All procedures were successful, and the stents remained patent until patient death. Promptly after stent placement, the IVC flow recovered, and the venous blood pressure in the IVC below the obstruction level showed a significant decrease from 20.8 ± 1.2 mmHg (mean ± SE) to 10.7 ± 0.7 mmHg (p < 0.01). Transient mild increase of right atrial pressure was observed in 1 patient. During the following week prominent diuresis was observed in all patients. Mean urine output volume in the 3 days before the stent therapy was 0.81 ± 0.09 l/day compared with 2.1 ± 0.2 l/day (p < 0.01) in the 3 days after. The edema and ascites decreased in all patients. The caval pressure change correlated well (r > 0.6) with the urine volume increase, and with the decreased volume of edema and ascites. The urine volume increase correlated well with the decrement of edema, but not with that of ascites. Improvements for various durations in the levels of blood urea nitrogen, serum creatinine, lactate dehydrogenase, fibrinogen, and platelet count were found (p < 0.05). These hematobiochemical changes were well correlated with each other and with the decrement of ascites. Two patients showed a low blood sodium level of 128.5 mEq/l after intensive natriuresis, and one of them died on day 21 with hepatic failure, which was interpreted as maladaptation aggravation. The mean survival time was 94.1 ± 34.1 days (mean ± SD), ranging from 21 to 140 days after stent treatment. Conclusion The stent therapy for IVC obstruction due to malignant liver tumors was followed by a series of physiologic and hematobiochemical consequences, most of them favorable but some possibly unfavorable. Rational interpretations and predictions of sequelae based on physiologic science including cardiology, hepatology, and nephrology would facilitate the best management of stent therapy for malignant IVC obstruction.