Non-thrombotic iliac vein lesions trigger “paradigm shift”

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Now that non-thrombotic iliac vein lesions (NIVLs) are more frequently recognised on modern imaging modalities, they are beginning to trigger a paradigm shift in standard vein work whereby there is now increasing emphasis on making sure that these patients do not have significant deep venous obstruction which must be taken into account when planning treatment.

That was the suggestion made by Ian Franklin (London, UK) at  the Venous Challenges Main Programme session of the 2016 Charing Cross Symposium (CX 2016; 26–29 April, London, UK).

He stated that this is a problem for those specialising in varicose veins as to how and when to assess whether there is a proximal obstruction and whether it is a significant component of the varicose symptoms.

Referring to the commonality of NIVLs, Franklin reported that in cadaveric studies, intraluminal lesions can be found in 20–30% of specimens, and in terms of extrinsic compression, a Cambridge study has recently found that over 60% of that series had evidence of an external compression of the vessel in asymptomatic patients on computed tomography (CT) scans done for other reasons.

“If you look at patients with severe chronic venous disease with C3+, obstructive lesions are found in >90% of these patients, which led Raju and Neglen to conclude that these lesions may have a permissive role in chronic venous disease—in other words, they are harmless in the majority of people, but as soon as an extra factor becomes involved, such as obesity or reflux, they suddenly then become significantly pathogenic,” he explained.

According to Franklin, there is now a great deal of evidence in the literature that deep vein stenting works. All the series show a very low complication rate, it seems to be safe, it seems to be durable, and there is a very good rate of ulcer healing, which suggests that the obstruction of the iliac veins is actually part of the disease process. However, indications are not always well-defined and the case mix is usually very heterogeneous. “Although we have a lot of evidence that deep venous stenting works, the literature does not give us much of a handle on who should be treated and possibly who should not,” Franklin said.

He maintained that while symptoms are the best indicators of which patients should be treated, they can be very non-specific and hard to quantify. Many large studies have shown a poor correlation between symptoms and the presence and the severity of the venous disease. Franklin added that there are wide disparities between phlebologists when allocating CEAP score to photographs of legs with venous disease, and there is therefore a need for something more objective.

As to which imaging modality should be used to diagnose iliac vein obstruction, he said that when using duplex ultrasound it can be difficult to see the central vein and venography tends to miss many of these lesions, but CT and magnetic resonance imaging can be helpful, as can various forms of plethysmography and pressure measurements.

As for what the future holds, Franklin maintained that in terms of evidence gathering, there should be rigorous reporting of symptoms and signs pre- and post-treatment, care should be taken to avoid mixing up mild and severe disease, conservatively treated patients must be followed-up, there must be improvements in non-invasive haemodynamic testing, and there is a need for randomised controlled trials.

In terms of patient selection for the future, Franklin suggested that it should be patients with rapid recurrence after treatment, those who have had multiple previous varicose vein interventions, those with severe symptoms which are believed to be venous in origin, patients with poor symptomatic response to superficial vein treatment, those patients with skin changes out of proportion to the apparent reflux, and finally, patients with non-healing and relapsing ulceration.

The most difficult cases, he added, “are the ones who present to us with apparently ordinary varicose veins, but with uncertainty as to whether there is a significant proximal obstructive component. I think that is going to represent the biggest challenge facing phlebologists in the near future.”