Cees Wittens writes for Venous News about the current state of deep venous obstruction interventions, what we might expect in the near future, and what is needed in terms of new technology, strategy and policy in 2018.
In general, everybody is focusing on better equipment to improve care, but if we look back and evaluate what has been published on deep venous obstruction (DVO) intervention and what is mentioned during recent meetings, I suggest we focus on improved patient selection and quality driven care first.
Unfortunately, to identify patients for a DVO intervention we need proper selection criteria, as we have in arterial disease: A 5.5cm diameter for infrarenal aneurysms, an ankle-to-brachial pressure index threshold in obstructive disease, or an internal carotid artery diameter reduction in symptomatic transient ischaemic attack patients.
As a result, we see patients being treated for DVO with hardly any improvement in quality of life (QoL) or clinical scores. Therefore, it is key that we develop the selection criteria to better predict which patient will improve after a successful intervention. This starts with the evaluation of the complaints of the patient and the possibility to improve the QoL. If this is not expected, an intervention should not be performed.
There have been publications showing that stenosis of more than 50% can be detected with magnetic resonance venography (MRV), duplex or intravascular ultrasound (IVUS), and should be treated. There are even studies comparing these diagnostic tools in order to select the best tool to identify those stenoses. But because all measurements are performed in a supine position at rest, maybe with Valsalva maneuvers or calf activities, they are not conclusive. At this point, there is no proof that a 50% stenosis rate relates to clinical symptoms, and therefore it is not an appropriate measure to select patients for an intervention. The presence of collaterals combined with 50% stenosis increases the chance that an intervention might improve the clinical scores and QoL.
In general, we also need a better uniform registration (volume flow, flow direction, vessel diameter, with or without flow augmentation) of the MRV, Duplex and IVUS outcomes in order to compare the results and learn which detected pathology influences outcome.
In acute deep vein thrombosis (DVT) these diagnostic tools are used to identify a DVT, but in all publications the identified DVT are called iliofemoral, femoral, proximal, central, peripheral and so on. However, these “locations” can refer to proximal of the knee or groin or even higher. We need a better classification, such as the Lower Extremity Thrombosis (LET) classification, to categorise these DVTs and evaluate different treatment strategies.
We tried to do pressure measurements in the chronic cases, but because these are also performed in a supine position at rest they hardly show any usable data. This is why we are developing a 24-hour pressure measurement in the common femoral vein to get more information and potential selection criteria. A technical solution to do this might be what we need in 2018.
The fact that we do not register the potential improvement is also related to the fact that the used scoring systems like the VCSS or Villalta are not adequate enough. For example, both scores lack a question related to venous claudication and score not specifically related to venous disease, e.g. oedema or symptoms, which also blur the outcome.
We need a better general applicable scoring system to quantify venous disease from varicose veins to venous ulcers with or without a previous DVT.
The same applies to the generic and disease specific QoL questionnaires. The generic questionnaires are, as expected, also influenced by other concomitant diseases and not all can be used to perform cost-effective analysis. The Eq5D5L questionnaire is the most appropriate, but not used consistently, making comparisons impossible.
Disease specific questionnaires also have their own restrictions. Some are only applicable for varicose veins while others can only be used in ulcer patients. A new generally applicable questionnaire should be developed combining the Eq5D5L with a new disease specific questionnaire in which questions related to venous claudication are also included.
All those clinical scores only address leg problems and we do not have any specific questionnaire for venous disease located in the upper extremity, nor for pelvic congestive syndrome (PCS). In PCS, more awareness is needed to identify obstructive disease, especially a May-Thurner Syndrome or a nutcracker syndrome.
Improvements in interventional equipment like thrombectomy devices, stents with optimal flexibility, porosity and radial forces etc., and postoperative care measurements like non-invasive flow augmentation devices, as well as of course the new direct oral anticoagulants are crucial for improved outcomes, but the above mentioned issues should in my opinion be addressed first.
Therefore, in 2018 our goals should be:
1To improve the diagnostic criteria and register all results in a standardised fashion, in order to identify clinically relevant criteria to improve care and patient selection. This will improve the quality of venous care and reduce inappropriate care, which unfortunately is still a realty and should be abandoned. An obligatory registry will potentially influence this.
2 A follow-up with standardised clinical and QoL scores will also measure the quality of care and can identify the physicians, departments or even hospitals that do better or worse.
3By using these benchmark data in a region or country, care can be improved where necessary.
4As a result, the driving force for everybody involved in deep venous obstruction interventions should be proper patient selection and quality driven care.
Cees Wittens is head of Venous Surgery at the Maastricht University Medical Center in Maastricht, the Netherlands
I think venous hemodynamics are poorly understood in general. As you mention, supine studies miss the effect of hydrostatic pressure. Venous flow, unlike arterial flow, is dependent on an inconsistent motive force (muscle activity) that is not replicated in most studies. Veins are capacitance vessels capable of significant changes in diameter. We have all seen patients with vena cava occlusion with little or no symptoms and others with debilitating symptoms. The same pathology but different outcomes.
The net result is that it is hard to quantify the anatomic or physiologic basis for symptoms a priori. Absent this knowledge, it is difficult to predict how altering the anatomy will result in patient improvement.
Available data and experience has shown that we are improving the condition of some patients. I agree we need to improve patient selection to achieve consistent results.