IVUS invaluable for precise iliac vein treatment
In a large series of iliac vein stent cases, a blinded comparison found intravascular ultrasound (IVUS) superior to venography in determining the proper location of treatment zones.
Researchers from The RANE Center at St. Dominic’s Memorial Hospital in Jackson, Miss., have performed a retrospective, single-center cohort study of 155 limbs treated for chronic iliac vein occlusion between 2013 and 2015.
The lead author of the comparison, Vascular Surgeon Myriam Montminy, MD, reported in the November 2019 edition of the Journal of Vascular Surgery: Venous and Lymphatic Disorders, that the RANE Center researchers noted that adequate assessment of the location and degree of stenosis and delineation of venous anatomy for optimal landing zones are key elements in the success of interventions to treat chronic obstructions of the deep venous system.
“While venography is more accessible and less expensive to perform than IVUS, an increasing number of studies demonstrate that IVUS is significantly more sensitive than venography in identifying stenotic lesions in the iliac-caval segments,” Dr. Montminy explained. “Our study aimed to take this one step further by comparing these modalities in identifying the key parameters required to guide stent placement.”
Key demographics of this series included:
- Age, years, mean (SD) – 59 (13)
- Male – 30 percent
- Left leg – 61 percent
- Post-thrombotic – 72 percent
- Non-thrombotic – 28 percent
With regards to evaluation of the main venous stenosis, venography, compared with IVUS, failed to identify the stenosis in 19 percent of cases; underestimated the degree of stenosis; and failed to accurately locate the stenosis in 68 percent of cases.
Further, in identifying the location of the iliac-caval confluence (the proximal landing zone), venography correlated with IVUS in 15 percent of cases, wherein IVUS revealed the confluence to be higher in 74 percent of cases (mean of one vertebral height higher).
Finally, with regards to the distal landing zone, venography correlated with IVUS in 26 percent of cases, wherein IVUS located the optimal site lower in 64 percent of cases.
“This study highlights that venography compared to IVUS is likely to be deficient in all three areas of concern in venous stenting cases – location of the maximal stenosis as well as the optimal proximal and distal landing zones,” Dr. Montminy added.
Venography is still a desirable adjunct in iliac vein stenting as it provides a panoramic view of the pathologic process, including collaterals, she said. “Additionally, IVUS may miss or provide only a partial image of certain lesions situated at the hypogastric-iliac and iliac-caval confluences due to the absence of a centering mechanism.”
While it is currently unknown if the superiority of IVUS in identifying key parameters essential for iliac vein stenting translates into improved clinical outcomes, the results of this study further defines the complementary roles venography and IVUS play in this growing area of vascular intervention.
This research article is open source and free to the public until Dec. 31 at vsweb.org/JVSVL-IVUS.