ABSTRACT
Objective To explore the relationship between the establishment of collateral circulation caused by iliac vein compression syndrom(IVCS) and the deep venous thrombosis (DVT). Methods Different types of ideal collateral circulation models and IVCS patient-specific models were numerically simulated using computational fluid dynamics (CFD) in combination with the blood stasis model. The relationship between blood retention and collateral types and cross-sectional area was studied, and the relationship with thrombosis was explored. Results Wall shear stress (WSS) at the distal end part of each ideal model was 0.3 Pa. After four cardiac cycles, the residual blood stayed at the stenosis and the distal end part for the lumbar ascending and pelvic type models, the old blood volume fraction (OBVF) varied with collateral cross-sectional areas, ranging from 5%-90% and 70%-80%, respectively. The OBVF of the coexistence model was above 80%. The WSS at the distal end part of the patient-specific model was 0.9 Pa, and the OBVF at the distal end part was 51.5%. Conclusions The stenosis and the distal end part are most prone to blood stasis, and closely related with DVT. The larger the collateral cross-sectional area, the more serious the blood stagnation. Blood stagnation of the coexistence model is higher compared with the model with lumbar ascending type and pelvic type.
ABSTRACT
We report the efficacy of catheter-directed thrombolysis (CDT) for acute deep vein thrombosis. Between January 2003 and August 2004, 20 patients were treated with CDT for occlusive femoral, ilio-femoral and vena caval thrombosis, for less than 2 weeks from onset. Average age was 56.4 years (range 30-78 years), 11 patients were male, and the duration of leg symptoms was 4.4 days (range 1-12 days). Routine temporary inferior vena caval filters were used, and a multi-lumen catheter was inserted from the popliteal vein. Urokinase was used via the catheter by the combination drip infusion method and pulse-spray method. All patients received heparin and stasis of venous flow was prevented with intermittent pneumatic compression. If thrombus remained, mechanical thrombolysis was necessary. Metallic stents were implanted for iliac vein compression syndrome and organized thrombus. Venographic severity score (VS score) and extremity circumference were used to evaluate the effects of treatment. The duration of the treatment was 5.0±0.28 days (range 2-9 days) and the total dosage of urokinase was 1, 025, 000±57, 000 units (range 360, 000-1, 680, 000 unit). One (5%) iliac vein compression syndrome and two (10%) organized thrombi were treated by implanted metallic stents. Giant thrombi was captured by temporary inferior vena caval filters in two patients, but there was no pulmonary embolism. Two patients had thrombophilia, one was antiphospholipid syndrome and one was protein S deficiency. There was an early recurrence in one patient and re-CDT was needed. The VS score deteriorated to 6.2±2.5 (post CDT) significantly (<i>p</i><0.0001) from 26.2±6.3 (pre CDT). CDT for acute deep vein thrombosis was effective and its early outcome was acceptable.
ABSTRACT
PURPOSE: Iliac vein compression syndrome (IVCS), first characterized by Cockett and Thomas in 1965, is the development of iliofemoral deep venous thrombosis due to compression of the left common iliac vein against the spine and pelvic brim by the right common iliac artery. Thrombectomy treatment of the underlying compression is essential if significant long-term sequelae are to be avoided. Surgical treatment options include venous reconstruction or venous bypass, but treatment using endovascular techniques have recently been described. This study was conducted to evaluate the usability of endovascular treatment (esp. thrombolysis with stent insertion) in a venous outflow obstruction resulting from IVCS. METHOD: During a 2-year period, 20 patients (17 women, 3 men; mean age, 60 years) presented with clinical and imaging findings consistent with IVCS. All patients presented with leg edema or pain. The mean duration of symptom onset was 6.6+/-4.4 days, ranging from 1 to 15 days. All patients were evaluated using a Duplex scan, computerized tomography and venography. After the ascending venography had been performed, an infusion catheter system was placed, and urokinase infused locally into the thrombus burden. After near complete clot dissolution, the residual left common iliac vein stenosis was treated by means of angioplasty and the placement of a Wallstent. All patients continued to receive oral warfarin. Patients were followed-up by means of clinical visits, and the stent patency was assessed by means of a Duplex scan or computerized tomography. RESULT: The total dose of urokinase used and the duration of infusion were 2.28+/-0.93 million unit, ranging from 1.00 to 5.20 and 46.8+/-14.8 hours, ranging from 14 to 72 hours, respectively. Grade III (complete lysis) thrombolysis was achieved in 17 patients. All 17 patients successfully received a Wallstent. The initial clinical success was 100%, with complete resolution of symptoms in all patients. One patient, with combined ovarian cancer, had a recurrent symptomatic deep vein thrombosis and complete occlusion of the stent due to thrombosis 2 months after treatment. However, no other patients showed evidence of deep vein thrombosis after treatment. The overall patency rate of the stenting at 18 months was 94.1%. There were no deaths, pulmonary embolism, cerebral hemorrhage or major bleeding complications. CONCLUSION: These results suggested that the treatment of iliac vein compression syndrome, using catheter directed thrombolytic therapy and venous stent insertion, was a safe and effective method at the mid term evaluation. These patients will continue to be followed up with screening tests to further define the long-term patency.