Evidence for deep venous reconstruction is “extremely weak”

Stephen Black

Stephen Black, St George’s Hospital, London, UK, told delegates at the Charing Cross Symposium (5–8 April 2014, London, UK) that most of the evidence for deep venous reconstruction is based on single-centre experiences, many of them small, and therefore “extremely weak”.

In his presentation, Black explained that the basis of analysing patients with deep venous disease is the CEAP classification, Villalta Score and the Venous Severity Score. However, he said, these tools do not provide a full picture of many patients who are treated for deep venous disease, “with no real understanding of the haemodynamic mechanisms of bringing these patients to be treated in the first place, and in addition these scores are based entirely on signs and symptoms.”

The same applies to the use of imaging, according to Black, where there is a lack of consensus whether CT or MRI is the best modality to assess deep venous disease patients. “The bottom line is that these are all axial image modalities with patients generally lying on their back so they do not provide us with information of the haemodynamics of the circulation. And the use of imaging ultimately ends up depending on what you have available in your institution, so you have to be slightly pragmatic,” he said, adding that at St George’s Hospital he uses CT.

He noted that the same applies to the use of IVUS and venography, and added: “With IVUS, the consensus seems to be that it is expensive and there has not been any evidence of whether it is a useful tool, so we do need to establish if IVUS is going to make any difference to our patients’ treatment. I have found it an indispensable tool for seeing exactly what the stent looks like after placement and making sure that I do not leave any residual stenosis, particularly if I am looking for residual clot or any other lesions that need treating after lysis. In addition IVUS has the potential to significantly reduce the radiation dose administered to the patient.”

Black then described the treatment pathway of deep venous reconstruction. “You treat the obstructive component first—whether it is proximal or distal, you want to eliminate the obstruction in the system—and the mainstay for this is going to be stenting (in this day and age bypass is reserved for patients with occluded stents or those who have significant symptoms that require an operation). You then treat the superficial reflux, and endovenous ablation will be the mainstay of that. Finally, you deal with the deep venous reflux that is left behind. Neglen and Raju say only approximately 5% of patients ever come to need any form of valve reconstruction,” he said.

Stenting in chronic patients, according to Black, achieves good results. He showed delegates the case of a patient treated with the Veniti stent and said that once the lesion was crossed and the stent was placed, there was a good resolution of symptoms. However, he said, “we rely a lot on Neglen et al (J Vasc Surg 2007;46:979–90) and Raju and Neglen (J Vasc Surg 2009;50:360–8) long-term data to provide us with any evidence for this,” and added, “An important take-home message with stenting of both chronic lesions and post-thrombotic lesions is that the patency rates are assisted primary and secondary. If you rely entirely on putting a stent and never following up your patient, a lot of these stents will block and you will have very poor patency rates.”

Black moved on to talk about patients for whom bypass surgery is the only treatment option. He showed the case of a femoro-caval bypass in which the patient had a stent that occluded and who presented with venous claudication and significant C6 lesions that were not healing. “Bypass procedures work well but are time consuming and you have to work hard to keep them patent. In addition, fistulae are still a controversial area where we are not entirely clear whether they are effective or not. In this particular patient, six months after his procedure, the bypass is still patent and the symptoms have improved markedly, but you have to be very careful in your patient selection; they need very good inflow otherwise there is no point in even attempting a bypass,” Black said.

He added that the results of bypass surgery also rely on single-centre experiences. “You certainly can get good results, but these are dependent on interventions as primary patency rates are poor. You have to be intervening in these patients, dealing with complications and following them up very carefully.”

In relation to valve reconstruction, Black said it is “perhaps the trickiest and most difficult part of deep venous intervention”. He added: “I spent some time with Oscar Maletti in Italy and his procedure for Neovalve reconstruction is a beautiful operation. He is an artist with this procedure and I do not know how extrapolable that operation is. Again we rely heavily on single-centre experience and mostly Kistner for primary valvuloplasty. Primary valvuloplasty is better than external valvuloplasty and you can reserve Neovalve for those more difficult cases. Endovenous techniques for valve replacement are on the way but nothing yet is suitable for valve reconstruction.”

The conclusion, Black said, is that we are in an era where evidence for deep venous reconstruction is extremely weak but advancing. “There are lots of single-centre experiences, but it is very difficult to interpret the data. We need to understand the haemodynamics of the deep venous system much more carefully than we do and we need to understand the relationship between the deep and superficial systems. We also need to understand what the passage from an asymptomatic patient with a May Thurner lesion and no problem to somebody with obstruction is and we need to clarify things like the role of IVUS and imaging in this disease.”