The use of dedicated nitinol venous stents across the inguinal ligament shows “good outcomes” in terms of patency but reinterventions may be required, according to Prakash Saha, Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, London, UK, who spoke about this topic at the American Venous Forum Annual Meeting (14–17 February, New Orleans, USA). The patency rates seen with these newer devices are comparable to data reported for the Wallstent (Boston Scientific).
“There has been a worldwide expansion on the use of endovenous technologies to reconstruct the deep venous system, with an increased use of dedicated nitinol venous stents. These have been designed to accommodate the wider venous anatomy but the first-generation of stents varies in flexibility and compressibility,” Saha said. “The European guidelines suggest that stenting across the inguinal ligament should be avoided but we know from the work of Seshadri Raju and Peter Neglen that stenting from a normal venous inflow segment is perhaps the most important feature.” Raju and Neglen have published data on venous stenting with the braided, stainless-steel Wallstent.
Saha told AVF delegates that the aim of his study from Stephen Black’s group was to examine patency rates in patients having deep venous reconstruction using nitinol venous stents that were placed across the inguinal ligament. It included all patients undergoing endovenous reconstruction using a dedicated venous stent between 2012 and 2015. The minimum follow-up was 12 months. Duplex ultrasonography together with cross-sectional imaging using CT and more recently MR venogram, was used in the study. Duplex ultrasound follow-up was then repeated immediately following the procedure, at two weeks, and three, six and 12 months following surgery. Villalta scores were taken before and after intervention, at six weeks, six months and 12 months.
During the period of the study, 102 chronic post-thrombotic patients (median age 39 years) were treated. As expected, left side symptoms were predominant (76% of patients) and the preoperative Villalta score was 15. The study included a number of venous stents: Vici (Veniti) 53%, Zilver Vena (Cook Medical) 27%, Wallstent (Boston Scientific) 14% and sinus-XL, sinus-Venous, sinus-Obliquus (Optimed) 12%.
Saha noted that these patients presented relatively good outcomes in terms of patency, “however, some did require reintervention”. Primary patency was 58%, primary-assisted patency was 71% and secondary patency was 86%. Perhaps the most important thing, he added, was the change in Villalta score from significant to mild disease (p<0.0001). “What is clear is that if you have a patent stent you will see improvements in patients’ symptoms,” he said.
Of the 102 post-thrombotic syndrome patients treated, the majority (71) required stenting across the inguinal ligament. When Saha and colleagues looked more closely at the outcomes it was possible to see that stents placed above the ligament yielded better primary (72% vs. 52%), primary-assisted (100% vs. 80%) and secondary patency (100% vs. 82%) than those placed across the inguinal ligament, “but this was an expected outcome”. Importantly, larger clinical improvement (Villalta score) was seen in patients with patent stents placed across the inguinal ligament (-11) than those with stents above the ligament (-9), though this likely was due to the fact that patients requiring stents often had more extensive disease and had worse symptoms to begin with.
Stent-related complications were seen in all the different nitiniol stents that were used in the study. Four patients experienced focal stent compression across the ligament. They were treated with balloon dilatation and the stent was re-lined with an additional stent together with division of the inguinal ligament at the maximal point of compression. In three other patients the investigators noted stent fracture during surveillance, however, none were symptomatic. “The dilemma was whether to treat these patients or leave them alone. We re-lined the stent in one patient and left the other two alone. Both patients seem to be doing well,” Saha said.
He concluded by stating that deep venous reconstruction is challenging, with complex patients, particularly those with post-thrombotic syndrome, potentially requiring reintervention and adjunctive procedures, and added, “In order to treat these patients, regular duplex surveillance is required to maintain patency. Looking at our data for post-thrombotic syndrome patients, stent patency seems to be comparable to Wallstent below the inguinal ligament. This experience is with the first-generation venous stents available and over time we will likely see better outcomes as stent design evolves and we learn from longer-term outcomes.”