April 2010

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What level of symptoms dictates that a patient should  undergo vascular intervention for superficial femoral  artery (SFA) disease?
  The answer may be elusive in some patients.   The typical  response is that revascularization is necessary when  lifestyle-limiting claudication occurs. This limitation, however,  takes several forms, which to one  person may not be critical, but to another  may be significant. For example, a  grandparent with limited mobility would  be happy to ambulate enough to follow  his or her grandchildren through the  course of a day, which may only necessitate  walking 200 to 500 feet at any one  time. But this distance may not be  enough for a golfer, for example, who can  only walk two holes instead of his or her  usual nine or 18.

With all of the device options available for treating   SFA  disease, how do you decide which platform is best for a  particular patient?
  The SFA remains a very difficult location to   determine the  best endovascular treatment method based on current evidence.  If we look at all of the currently available devices, we  can generally place them into several key categories: medical  therapy, balloon angioplasty, stent placement (open or  graft), and atheroablative technology (excisional, laser, or  rotational). All patients, regardless of lesion status, should  receive best medical therapy and include an exercise program  (when appropriate), hypertension control, and  lipid/diabetes control. To me, the data, although not crystal  clear, have suggested that for short focal lesions (TASC A) in  this territory, percutaneous transluminal angioplasty (PTA)  is a very good start, with acceptable patency rates of 70% or  higher. Other forms of revascularization&mdashlstenting or the  atheroablative technologies—have equally good results, but  the general costs of the atheroablative technologies make  this approach for these lesions less attractive unless proven  to be more cost effective.

For longer or more complex TASC B or C lesions,  ABSOLUTE and the subsequent DURABILITY trials suggest  stenting to be far better in the first year than angioplasty  alone (63% vs 37%, respectively). However, the benefit of  this approach quickly dwindles in the second year such that the   endoprosthesis benefit is nearly lost, although still with  a higher primary patency rate compared with angioplasty  alone, demonstrated in the 2-year ABSOLUTE data (54% vs  33%, respectively). For longer lesions, the use of covered  stent technologies has not translated to improved primary  patency rates at the end of the first year, as shown in  VIBRANT (53%). Further, the alternative  atheroablative therapies have a poor primary  patency rate in the first year at nearly  40% to 50% at this length; the benefit  through the second year is similar to that  of stents and provides some evidence that  a nonstenting approach may afford a longterm  clinical and anatomic benefit comparable  to stents.

No device to date has shown great utility  in long total occlusions and calcified  arteries (TASC D) in the SFA. Currently,  there are no compelling data in this patient  subset to the point that no trial (with the exception of  VIBRANT) has enrolled this type of patient with highly difficult  long occlusions or stenoses, and no trial likely will. We  have very little data on calcified lesions. What is the best  way to treat these lesions? Should we use PTA alone or  does this lesion subset require changes in arterial compliance  through rotational atherectomy devices to then placate  the artery to then balloon or stent? These data are  early in their formulations, and no definitive conclusions  can be drawn as of yet on their usefulness or applications  in these specific locations.

How would you summarize   your own approach to the  various lesion types?
  For TASC A lesions, I perform PTA first,   with provisional  stenting second. Atheroablative treatment is acceptable,  although the costs may be prohibitive. For TASC B and C, I  perform stenting primarily with the understanding that I  will have a 50/50 chance that the stent is patent at the end  of 2 years. Patients need to be aware of and understand this  possibility. Atheroablative technologies may provide primary  patency rates in the same ballpark as stents at the  end of 2 years and thus may be an attractive approach in  this patient group for both clinical and anatomic patency.  For TASC D lesions, I suggest starting with stenting. If this fails at   the end of 6 to 12 months, it is time to consider surgical  revascularization.

What remains unclear is in which   lesions, if any, drug-eluting  balloons or drug-eluting stents will play a role in the SFA.  The THUNDER trial and the early registry data from Zilver  PTX (Cook Medical, Bloomington, IN) seem to show us that  in the future, revascularization in the SFA will incorporate  these antirestenotic technologies in some form. However,  the expectation is high that they will provide a great benefit  in this very difficult territory.

What is one of the most   important techniques or strategy  adjustments you have made since your initial experiences  using atherectomy in the SFA?
  Early in our experience, we   believed that atherectomy was  a sound alternative to stenting given the extremely dynamic  nature of the SFA; leaving an endoprosthesis behind was less  attractive. I would still argue that the clinical benefit of  atheroablative technologies is very good. However, clinical  benefit and durability are not the same, with the primary  patency rates of atherectomy in longer lesions or multilevel  disease being near or below 50%.My biggest adjustment  has been that we treat longer lesions, TASC C, or the totally  occluded, TASC D, arteries with stenting rather than  atherectomy with the understanding that we will likely be  returning to retreat in 12 months and perform surgical  revascularization in 2 to 3 years.

What is the current   focus of your research in the SFA?
  My principal research focus   has been technologic development  in the SFA—searching for the “perfect” combination  therapy to obtain the best primary patency rate and  durable clinical benefit in patients with claudication or limb  ischemia.

DEFINITIVE LE is a   registry trial evaluating SilverHawk  atherectomy (ev3 Inc., Plymouth, MN) in a real-world registry.  This trial, in which I serve with Jim McKinsey, MD, of  New York, as global principal investigators, will be the  largest peripheral trial ever completed to date, evaluating  800 patients with peripheral arterial disease. The protocol  includes patients with infrainguinal disease and will treat  patients with claudication as well as critical limb ischemia.  Patients with diabetes will be evaluated regarding their outcomes  with SilverHawk, and we will also perform plaque  analysis in a subgroup to further define some proteonomic  signals in the treatment of our patients with peripheral vascular  disease. Primary endpoints will be primary patency  rate of the lesions at 12 months, followed further for the  claudicant group, and limb salvage rates for the critical limb  ischemia patients. The trial is currently enrolling and will  likely be completed in late 2010.

SUPERB is   a stent registry evaluating the Supera stent  (Idev Technologies Inc., Webster, TX) in an objective performance  criteria-driven evaluation of the stent for  infrainguinal disease. This trial, for which I serve as a conational  principal investigator with Ken Rosenfield, MD, of  Boston, will seek US Food and Drug Administration  approval for the stent in the SFA. This unique stent with  an interwoven nitinol design allows unusually high flexibility  without any significant compromise of radial  strength. This design allows for the unique vessel forces of  the SFA to be relatively unchanged despite the stent presence  but still allows significant radial force to scaffold the  artery where needed. This trial is currently enrolling and  should be completed in 2010.

I also serve as the Data and Safety Monitoring Board  chairman for other trials and serve on the steering committees  of several other trials.

What are the most significant   unanswered clinical questions  that future trials and studies must seek to address?
  Unfortunately,   it remains the same issue that Andreas  Grüntzig raised after his PTA result in 1978: PTA may be  useful if we can show scientifically that it is superior to surgery.  Unfortunately, the data as we know it in the SFA territory  are exceedingly poor. In lieu of “getting an indication”  for the SFA by enrolling short lesions or the patient subset  in which we know the technology performs well, we need  to see the data in real-world patients with long SFA lesions  and occlusions to know the best evidence-based approach  for our patients. We need to be able to effectively discuss  with them all of these issues and understand their expectations  for any and all outcomes to make the best decision  available.

With the   economics of health care under intense scrutiny,  is there any push to use fewer devices to achieve  revascularization? To what degree do economics have an  impact on decision making in your practice?
  Economics will play   an ever-increasing role in our  patients’ therapy as it does currently. This is critical to  understand in that if a new device looks good or can  achieve an open artery but costs several thousand dollars  before balloon or stenting, the marginal costs will be exorbitant  if the device is used routinely. If, however, that same  device is used once with adjunctive therapies that may cost  an additional amount but affords greater primary patency  and clinical durability compared with other technologies,  then I would argue this device would become the default  device in the SFA if not elsewhere. It could then be shown  to have significant cost savings at the end of 1 year and  beyond due to fewer repeat revascularizations compared to  other current technologies.

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