Abstract: Objective:To investigate the application value of inferior vena cava venography in correlation between the subtypes of inferior vena cava obstruction and calcifications at the obstruction in BuddChiari syndrome (BCS).
Methods:The retrospective cross-sectional study was conducted. The clinical data of 41 patients with BCS who were admitted to the Affiliated Hospital of Xuzhou Medical University between January 2009 and December 2016 were collected. There were 29 males and 12 females, aged (53±10)years, with a range of 34-70 years. Fortyone BCS patients underwent computed tomography (CT), inferior vena cava CT venography and digital subtraction angiography (DSA) within 2 weeks. Balloon dilatation and (or) endovascular stent implantation of inferior vena cava were performed according to calcification morphology and location of the inferior vena cava obstruction detected by DSA. Observation indicators: (1) calcifications of inferior vena cava obstruction; (2) intraoperative situations of interventional therapy; (3) correlation between the subtypes of inferior vena cava obstruction and calcifications at the obstruction; (4)follow-up and survival situations. follow-up using outpatient examination of inferior vena cava venography was performed at 3, 6, 12, 24, 36, 48 months postoperatively to detect postoperative clinical manifestations, complications and survival situations up to December 2018. Measurement data with normal distribution were represented as Mean±SD. Count data were represented as absolute number and comparison between groups was analyzed using the chisquare test. The likelihood ratio test was used to analyze the correlation between the subtypes of inferior vena cava obstruction and calcifications at the obstruction. The degree of correlation was detected by Cramer′s V contingency coefficient.
Results:(1) Calcifications of inferior vena cava obstruction: of 41 patients, 17 had no calcification at the inferior vena cava obstruction and 24 had calcifications at the obstruction. Calcification location in 24 patients: there were 17, 4 and 3 patients with proximal, distal, both proximal and distal calcifications at the inferior vena cava obstruction, respectively. Calcification morphology: punctate and irregular calcifications were detected in 20 and 4 patients, respectively. Calcification distribution: 20, 3 and 1 patients had scattered, cluster and diffuse distribution, respectively. (2) Intraoperative situations of interventional therapy: of 41 patients, 21 underwent balloon dilatation and 20 underwent balloon dilatation combined with endovascular stent implantation. Two patients were detected hematoma at the puncture site of right femoral vein and treated using pressure dressing. One patient encountered rupture of balloon due to diffuse calcifications at the inferior vena cava obstruction and was improved after continual replace of balloon for 3 times. One patient had pulmonary embolism caused by detachment of the thrombosis at the distal obstruction during the balloon dilatation and was given anticoagulation therapy combined with thrombolytic therapy using largedose of urokinase. The other 37 patients underwent successful interventional therapy without exceptional circumstances. (3) Correlation between the subtypes of inferior vena cava obstruction and calcifications at the obstruction: of 24 patients with calcifications at the inferior vena cava obstruction, 13 had membrane obstruction, 7 had segmental obstruction and 4 had fenestrated membrane obstruction. Of 17 patients without calcifications at the inferior vena cava obstruction, 3 had membrane obstruction, 13 had segmental obstruction and 1 had fenestrated membrane obstruction. The likelihood ratio test showed that the subtypes of inferior vena cava obstruction were associated with calcifications at the obstruction (x²=9.293, P<0.05), with the correlation coefficient V as 0.466. Further analysis showed a correlation between membrane obstruction of inferior vena cava and calcifications at the inferior vena cava obstruction (x²=8.121, P<0.05), no correlation between segmental obstruction and calcifications at the inferior vena cava obstruction, also no correlation between fenestrated membrane obstruction and calcifications at the inferior vena cava obstruction (x²=3.395, 0.004, P>0.05). (4) follow-up and survival situations: 41 patients were followed up for 24.0-48.0 months, with a median time of 37.1 months. Postoperative ultrasound showed smooth backflow in the inferior vena cava, different degree of improvements in the lower limb swelling and varicosity in 38 patients. Embolisms in the inferior vena cava obstruction remained existent in 3 patients, 1 of whom showed significant decreasing of embolisms. There were 2 patients found restenosis and undergoing endovascular stent implantation. All the 41 patients survived.
Conclusions:The subtypes of inferior vena cava obstruction are associated with calcifications at the obstruction in BCS. Inferior vena cava venography evaluating calcifications at the inferior vena cava obstruction in BCS can be helpful for diagnosing the subtypes of inferior vena cava obstruction and guiding its interventional therapy.