In this interview, Vascular News speaks to Prakash Saha, King’s College Hospital, London, UK, about the growth of deep venous treatment and how the field can best address the ever-growing list of challenges.
What are the challenges you face in offering therapies for treating deep venous disease, and particularly venous outflow obstruction, to your patients?
Endovascular deep venous therapy is in its infancy. While pioneers in this field such as Seshadri Raju and Peter Neglén established the initial foundations, there is still much to learn. Both the patients who require deep venous intervention and the interventions themselves can be complex, particularly in the post-thrombotic limb. There is a need to treat these patients in a multidisciplinary team environment involving haematologists and vascular interventionalists, while postoperative care, including the use of anticoagulation and subsequent surveillance, is yet to be standardised. Although the development of dedicated nitinol venous stents has revolutionised current practice, these are still in the first generation of design. Optimal balance of strength and flexibility, both within individual patients and within different venous segments, requires further evaluation, and stent design is likely to improve with increased experience and robust long-term data. With that in mind, I think that the biggest challenge will be to ensure that the early clinical benefit can be maintained. Venous patients are often relatively young. We are therefore aiming for improvements to last many decades.
How has your thinking about these challenges and your approach to venous intervention differed from what traditional vascular surgery may have taught you?
Endovascular technology has revolutionised vascular surgery. Open venous interventions were previously offered in few centres and in only carefully-selected patients. Although judicious patient selection is still required, the minimally invasive nature of current deep venous interventions has increased the inclination of both patients and their physicians to try surgical treatments. In the acute setting, reducing the risk of post-thrombotic syndrome following an iliofemoral deep vein thrombosis by lysis and possible stenting has become the standard of care in many centres. There remain a large number of patients, however, who were historically treated with anticoagulation alone. These patients, who can present with painful, swollen and sometimes ulcerated post-thrombotic limbs, are motivated by the potential to improve their quality of life, which is often badly affected. This differs from arterial surgery, which principally aims to save life or limb rather than improve quality. Treatment of deep venous disease is quite distinct from arterial interventions. The anatomy, behaviour of vessels, flow rates and unique disease process involved in venous pathology means that deep venous intervention should be considered as a separate entity within the remit of the vascular surgeon.
As you have established a venous practice and addressed these challenges, what are a few of the interesting things you have learned?
Our deep venous practice has been growing over the last three years and as a group we are still learning. One of the many interesting things that we have discovered is the need to ensure meticulous attention to detail when dealing with these patients. We have a thorough preoperative work-up involving cross-sectional imaging, venous duplex ultrasonography, and multidisciplinary team discussion before offering any intervention. At the time of surgery, we place pneumatic compression devices around the limbs, are particular about the timing of anticoagulation before and after intervention and use intravascular ultrasound together with venography to aid precise placement of a stent. Postoperative care with dedicated vascular nursing staff facilitates early discharge, while our vascular ultrasonography lab ensures that these patients have appropriate surveillance by skilled ultrasonographers. We believe that any deviation from these protocols can compromise results and lead to a loss of stent patency. We collect robust longitudinal data on all patients that we treat and regularly analyse our outcomes to examine where improvements can be made.
What advice would you offer to someone who is thinking about specialising or adding deep venous therapies to their endovascular practice?
This is an exciting area to be involved with and is a massively expanding field with new products emerging. I have been fortunate to have been trained by Stephen Black and mentored by Peter Neglén. I think that anybody considering adding deep venous therapies to their practice should find a suitable mentor with an established practice in order to learn the subtle differences that need to be considered when treating patients with deep venous disease. I also suggest to start treating patients with localised lesions affecting the iliac vein and who will be compliant with postoperative anticoagulation. Finally, be prepared to reintervene early if required, as our data suggest that the first six weeks are the most critical in maintaining stent patency.
What do you think are the highest priority questions that have to be answered about deep venous therapy that will drive treatment into the mainstream?
Medium- and long-term outcome data will dictate whether deep venous intervention will be successful. We believe that there are a number of variables that lead to a loss of stent patency. A better understanding of these factors will lead to the development of treatments that encourage improved stent patency, which is an area of active research within our laboratories.
What is next for you in growing your deep venous practice and expanding contributions to this field of knowledge?
We are fortunate to have a team of research scientists led by Alberto Smith who we work closely with. Together with the Department of Imaging Sciences at King’s College London, we were recently awarded a research grant from the British Heart Foundation to investigate novel MRI sequences to better characterise the structure of venous thrombi in-man. We hope that these sequences will lead to individualised therapy and improve preoperative diagnoses when planning venous interventions.