OK, post-Radeck stent candidates are asking themselves some hard questions right about now.
I've been digging around trying to get some idea of the safety and durability (patency) of venous stents.
This isn't easy since the jugular stents are a novel application.
At first I researched the stents used in Venous Insufficiency of the legs - in which the Iliac vein is frequently stented - and with very good results. The stents tend to stay in place and not fracture ....
Quote:
"Patency of iliac vein stents appears good, with primary patency of 75% at 3 years. Close follow-up is mandatory to ensure that stent patency is maintained. Also mandatory is to intervene early in patients with recurrent symptoms that may indicate in-stent restenosis, which occurs in 23% of patients."
Oh, and note that in these cases, the gold standard test seems to be the doppler ultrasound:
Quote:
"Intravascular ultrasound scanning was routinely performed because transfemoral venography had poor sensitivity for the detection of iliac vein stenosis"
However, the safety record of these stents is thought to be largely due to the location, which is not subject to flexion and external (extrinsic) pressures.
So ... if lower jugular or azygos vein stenoses are in locations not subject to lots of pressure and motion, the safety of iliac vein stenting may be applicable.
But what about the upper jugulars, where it is extremely crowded - and sometimes pinched by bony structures (ie spurs on vertebrate)?
For this I researched subclavian stenting - such as used for venous Thoracic Outlet Syndrome (or 'Paget-Schrötter syndrome').
In this condition, the axillary/subclavian vein is pinched off by bony structures (ie the first rib).
Here I found many references to problems with stents - they wanted to use them since angioplasties don't hold up against the extrinsic pressures, but have found that unless the external pressures are first addressed (by partially removing the first rib to make room in the outlet, for example), the stents can easily fracture or collapse ... especially problematic when we're looking at decades ahead, and since upper jugular stents, unlike Thoracic Outlet Syndrome patients', are not easy to access surgically later ...
Quote:
"The use of stents alone without first-rib resection, however, appears to be associated with stent fracture."
"Stenting of the axillary/ subclavian vein as a modality of treatment for this condition is contraindicated 5. Many patients that develop this syndrome have an underlying narrowing of the thoracic outlet (osseous or fibromuscular). A stent inserted under these conditions may not deploy properly because of the external compression and may induce further thrombosis and therefore further compromising the already tenuous venous outflow."
"Most authors do not recommend stent placement without surgical decompression (rib removal) because the stent itself may be compressed or become fragmented by the thoracic outlet narrowing. Dowling et al reported a case of venous thoracic outlet syndrome treated with thrombolysis, angioplasty, and stent placement without immediate first-rib resection. The case was later complicated by stent fracture.31 Meier et al reported a series of 6 patients who underwent venous stent placements immediately after thrombolysis for venous thoracic outlet syndrome and 2 patients who underwent delayed stent procedures. Two of the 6 patients who underwent immediate stent placement did not undergo immediate surgical rib resection, and both patients had the complication of stent fracture. Long-term (1-3 y) patency was achieved in 6 of the 8 patients.32 "
"In summary, stenting and stent-grafting of the lateral segment of the subclavian vessels where the clavicle crosses the first rib may be associated with stent fracture. This seems to affect all types of devices, including covered stents. Future device development should focus on materials capable of withstanding repeated deformation to improve long-term results. In the interim, resection of the first rib may help to prevent this sequela, although it is an unproven strategy. Until this problem is solved, stenting of this portion of the subclavian vessels should be undertaken with caution."
Finally - and I found this important given the images I have seen of stented veins in constricted upper jugular spaces:
Quote:
Finally, proper expansion of a stent after deployment must always be verified with radiography on fluoroscopy in different projections. The radial strength of the stent is greatest when it is expanded in a circular form. If it is expanded ovally, the stent is more prone to collapse by two-point compression forces.
(from
http://www.ajronline.org/cgi/reprint/160/5/1123.pdf)
Further reading:
Subclavian Stents and Stent-Grafts: Cause for Concern?
Thoughts?
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