By Hratch L Karamanoukian MD FACS RVT RPVI RPhS DABVLM (2009)
Iliac vein stenting
After catheter directed thrombolysis for iliac vein thrombosis, iliac vein stenting is performed to treat venous outflow obstruction.
I am reviewing an article published by Efthymios D Avgerinos and colleagues from Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pa. and Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pa. The reference is provided below.
What is the background and premise of the study ?
The authors state that information on the outcome of proximal and distal stent extension are limited.
1) Proximal stent extension to the vena cava may obstruct the contralateral iliac vein.
2) Distal stent extension below the inguinal ligament contradicts common practice for arterial stents.
What is the aim of this study ?
To assess outcomes and predictors of failure of iliac vein stents and contralateral iliac vein thrombosis, taking into consideration stent positioning.
Whart is the design of this study ?
This is a retrospective analysis.
What are the methods of this study ?
Consecutive patients who underwent thrombolysis and stenting for DVT between May 2007 and September 2017 were identified from a prospectively maintained database.
Operative venograms were reviewed for proximal stent placement (covering >50% contralateral iliac vein orifice) and distal placement across the inguinal ligament.
What are the endpoints for this study ?
1) End points were ipsilateral DVT recurrence
2) Post-thrombotic syndrome (PTS; Villalta score ≥5)
3) Contralateral DVT.
What are the exclusion criteria for this analysis ?
Patients with chronic contralateral DVT or contralateral iliac vein stenting at baseline were excluded from the contralateral DVT outcome evaluation.
What were the statistical methods to analyze the data in this study ?
Survival analysis and Cox regression models were used to determine outcomes.
What are the study results ?
142 patients underwent thrombolysis.
Of 142 lysed, 73 patients (12 bilateral DVT) were treated with various combinations of thrombolytic techniques and at least one self-expanding iliac stent (77 stented limbs).
Thirty-day recurrence developed in nine (12.3%) patients.
The 3-year primary patency and secondary patency rates were 75.2% and 82.2%, respectively.
The single predictor for loss of primary patency was incomplete thrombolysis (≤50%; hazard ratio [HR], 7.41; P = .002).
Overall, 3 of 12 (25%) stents extending below the inguinal ligament occluded at 1 month, 2 months, and 9 months, respectively.
The overall rate of PTS (Villalta score ≥5) in the stented cohort was 14.4% at 5 years. This was predicted by incomplete lysis (<50%; HR, 7.09; P = .040), stent extension below the inguinal ligament (HR, 6.68; P = .026), and male sex (HR, 6.02; P = .041).
Of the 17 stents that extended into the contralateral common iliac vein and 58 stents that did not, there were 1 (5.9%) and 5 (8.6%) contralateral DVTs (P = .588) at an average follow-up of 27.4 ± 33.7 and 22.2 ± 22.3 months (P = .552), respectively.
What are the conclusions of this study ?
1) Iliac stenting after thrombolysis for acute DVT guarantees high patency and low post thrombotic syndrome (PTS) rates, provided adequate thrombus resolution has been achieved before stent placement.
2) Stent placement below the inguinal ligament does not affect the patency but may be associated with a higher PTS rate.
3) Stenting proximal to the iliocaval confluence, although a precipitating factor, may not independently increase the likelihood of contralateral DVT.
Reference: AVgerinosED, Saadeddin Z, Abou ALi AN, Pandya Y, Hager E, Singh M, Al Khoury G, Makaroun M and Chaer RA. Outcomes and predictors of failure of iliac vein stenting after catheter-directed thrombolysis for acute iliofemoral thrombosis. J Vasc Surg Venous Lymphat Disord 2019 Mar;7(2):153-161.