YES: New tech promotes treatment where none is needed.
BY SAMUEL P. MARTIN, MD
As science and technology continue to advance, we have the ability to treat more and more conditions with less invasive, better-tolerated procedures. In the realm of vascular disease, this has been evidenced by a variable explosion in the endovascular treatment of arterial disease. With new technology, we have witnessed a tremendous relaxation of former standards in the pursuit of “quality of life.” Our new hammer is ever searching for a nail, resulting in the treatment of “anatomical” disease, such as seen in endovascular stenting of renal artery stenosis.
Nowhere is this trend becoming more evident than in the treatment of May-Thurner anatomy.
Dr. Samuel P. Martin
Despite years of awareness, there is neither an accepted radiologic definition for May-Thurner syndrome, nor established diagnostic criteria. Fortunately, our ability to image has improved from biplanar venography, formerly the gold standard.
Because May-Thurner is a permanent process, the luminal diameter of the iliac vein should not change with patient positioning. Now, with the recent development of blood pool imaging using contrast agents such as gadofosveset trisodium, magnetic resonance venography (MRV) studies can be performed in supine and prone position on a single dose of contrast. This would seem to obviate the former limitations of biplanar venography or contrast CT or traditional MRV, and would appear to provide an objective means of evaluating May-Thurner anatomy. However, upon evaluation of patients with lower-limb venous disorders, a prevalence of left common iliac vein compression was found in 14%-32% of patients, but a prevalence of May-Thurner syndrome in only 2%-5%, leading to the conclusion that left common iliac vein compression is necessary but not sufficient to cause the syndrome.
Thus, the point to be made: May-Thurner anatomy does not equal May-Thurner syndrome (Diagn Interv Radiol. 2013 Jan-Feb;19[1]:44-8).
Sadly, at the present time, there are no clear-cut guidelines.
With the advent of intravascular ultrasound (IVUS), we are seeing a large number of patients with the suspect anatomy undergoing treatment with balloon angioplasty and stents in the iliac system before adequate treatment of chronic venous insufficiency (CVI) in the extremities. What are the consequences? We have no data on primary or secondary patency of these stents (usually Wallstents). How often is anticoagulation necessary, and, is this permanent? I hate to suggest an industry or monetary motivation, but we are even seeing advertising for stent treatment of May-Thurner syndrome for people who have had treatment of their CVI (often with little or no swelling and minimal pain) with angioplasty and stenting. We also have seen patients who have undergone the procedure and had to have secondary procedures and long-term anticoagulation. Worse, they never had the procedure adequately explained, including potential complications or the possibility of future problems, procedures, or permanent anticoagulation.
So, as we face a situation – May-Thurner anatomy – which exists in more than 20% of our population, it raises several questions that need to be answered as we marshal our ever-increasing health care expenditures. Can we clearly define indications for further investigation and possible intervention, realizing that the syndrome of increased pain, swelling, and risk of thrombosis only exists in 2%-3% of those with the anatomy?
As McDermott and associates have shown in gated MRV studies, conditions such as hydration and especially position can significantly affect anatomical findings. My feelings based on 30-plus years of experience is that treatment of the leg should take precedence, and only after this avenue has been exhausted should one progress to suprainguinal investigation unless there is swelling of the entire leg. What are the long-term consequences of a Wallstent in the venous system, and are we “correcting” one risk by supplanting it with another – the long-term risk of stent thrombosis and subsequent interventions with long-term anticoagulation? There have been no reported cases of pulmonary emboli with May-Thurner and it is thought that the “spur” (synechiae) have some protective properties. In contrast, a stent is a definite theoretical risk for thrombosis, and even embolization.
Dr. Samuel P. Martin is a vascular surgeon in Orlando.
NO: Or rather, ‘maybe,’ by unethical practitioners.
BY ENRICO ASCHER, MD
Significant ipsilateral iliac vein stenosis or occlusion may have continued untoward effects in symptomatic patients particularly those with advanced venous stasis changes including venous ulcerations, skin discoloration, edema and/or pain (CEAP class 3-6). Conversely, successful iliac vein stenting (IVS) has been shown to normalize venous outflow, enhance calf vein muscle pump function, improve venous claudication, decrease pain, ameliorate edema, and accelerate wound healing.