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The Take Home: ISET
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From Feb. 6 to Feb. 10, 2016, the 28th Annual International Symposium on Endovascular Therapy was held in Hollywood, Florida.
Cardiology Today’s Intervention was at the meeting and obtained insights about presentations from a number of experts, including Editorial Board member Gary M. Ansel, MD, FACC, of OhioHealth Riverside Methodist Hospital, Columbus, Ohio; ISET 2016 Program Director Barry T. Katzen, MD, FSIR, of Miami Cardiac and Vascular Institute and Florida International University; Lindsay Machan, MD, of the University of British Columbia; and Jihad A. Mustapha, MD, FACC, FSCAI, of Metro Health Hospital, Wyoming, Michigan.
ALGORTHM FOR TREATMENT OF PERIPHERAL ARTERY DISEASE
Ansel: I shared a potential treatment algorithm for superficial femoral artery and proximal popliteal artery disease. We have to differentiate between the research process for the typical FDA approval length of 4 cm to 15 cm and the really long lesions we see in clinical practice, which may average up to around 30 cm. We have a lot of options we didn’t have before for to-short moderate-disease, but we don’t have much data for longer lesions.
The question is: Where do we go now? At our institution, we typically divide patients into different populations. For patients with moderate to mild calcification, we typically will do predilation with balloon angioplasty first, then, if there is a good result, we use a drug-coated balloon, and if there is a bad result, we use a drug-eluting stent. For longer lesions, we have a lot of options, including DCB, DES and stent grafts, but we don’t yet know which is best for each patient.
Photo credit: Katie Kalvaitis
For more heavily calcified lesions, we have to look deeper into our toolbox to make sure we get a big enough mean lumen diameter to predilate patients really well or to attempt debulking with atherectomy. There is some discrepancy in the data over whether calcium really decreases the efficiency of DCB. We are often doing balloon angioplasty and then using a nitinol woven stent (Supera, Abbott Vascular), because it now has good 3-year data. We have a cost-effective, data-based algorithm that we can use until we have more comparative data for the different technologies. There are some very early data that the use of directional atherectomy and DCB may be of benefit as well.
LIBERTY 360° DEMOGRAPHIC STUDY
Mustapha: The majority of trials for PAD are based on one device, and usually exclude high-risk patients such as those with severe critical limb ischemia (CLI; Rutherford class 6). As a result, physicians have limited evidence regarding the use of endovascular devices for this type of advanced disease.
I presented an interim demographic analysis from LIBERTY 360°, a study to evaluate the procedural and long-term clinical and economic outcomes with all FDA-approved technologies to treat claudicants and patients with CLI. We have enrolled 1,204 patients (approximately 500 with Rutherford class 2 or 3, 600 with Rutherford class 4 or 5 and 100 with Rutherford class 6) and will follow them for up to 5 years.
In this analysis of the first 600 patients, we found that men tend to have higher risk for PAD, including advanced CLI. We expected to see age increase as Rutherford class increased, but in fact it was the opposite, especially for Rutherford class 6. We expected some racial discrepancies, but what we found was surprising. White patients presented for care a lot earlier than black patients, and the interaction between race and Rutherford class was statistically significant, with approximately 30% of the Rutherford class 6 population consisting of black patients, compared with 13.7% of the Rutherford class 2 and 3 population being black. We saw a similar trend with Hispanics vs. non-Hispanics, with a significant jump in Rutherford class 6 in Hispanic patients. The data indicate racial discrepancies in PAD treatment, which warrants further investigation.
There was a directly proportional increase in diabetes with rising Rutherford class, and even more of a jump for patients with renal disease or on hemodialysis. Toe-brachial index was the only test that correlated properly with CLI. There were also a lot of amputations at the higher levels of Rutherford class.
Many of these patients, especially those with Rutherford class 6, would never be considered for clinical trials. This will provide unprecedented evidence that these difficult patients can be treated.
OCCUPATIONAL HAZARDS
Katzen: For this session, the main area of interest we were trying to communicate with our colleagues was the occupational health hazards of working in the interventional space for all disciplines including cardiologists, radiologists and vascular surgeons. There are hazards to working in this environment that can be cumulative over many years, from radiation exposure to musculoskeletal issues to cataracts. During the Town Hall session, there were a great number of presentations, and a lot of interest and some pretty scary reaction from many of the registrants, as we tried to increase awareness of the radiation and other work hazards of our interventional space. It also became apparent that there are few requirements for companies making protection equipment to provide documentation that products deliver expected results. The good news is, ISET delivered a very powerful message with very specific takeaways to our registrants about what we can do to improve safety in their work environment.
Machan: In one presentation, I highlighted 10 tips for interventionalists to reduce their radiation exposure.
No. 1: Learn a bit of physics. The first thing to know is that the main source of exposure to us and our staff is scatter radiation.
No. 2: Understand the effect of angulation to prevent a high dose to your face.
No. 3: Limit fluoroscopy time, using it only to observe objects in motion. Use last image hold, fluoroscopy loops and digital magnification as strategies.
No. 4: Lower the intensity. Use the lowest fluoroscopy dose yielding adequate image.
No. 5: Store fluoroscopy images for posterity.
No. 6: Use magnification only as needed. If you’re increasing image magnification from 0 to the maximum, you actually increase your radiation dose, depending on the machine you’re working on, by up to 74%. Moving the screen closer to where you are may help.
No. 7: Step away from the fluoroscopy, and stay as far away from primary beam and the X-ray tube as possible. People are now standing in room for digital acquisitions. If you don’t need to be there, get out.
No. 8: Use protection. I insist on floor-to-ceiling protection. In 2016, eye protection is mandatory. It is important to choose the right kind of leaded eye protection for the practice you have.
No. 9: Use cross-sectional imaging, which will decrease your fluoroscopy time. Use it also for planning.
No. 10: Park your ego. Don’t expose yourself to radiation just because you don’t want to miss cases or think people won’t value the procedures you do anymore.
Disclosures: Ansel reports financial ties with Abbott Vascular, Boston Scientific, Medtronic and W.L. Gore. Mustapha reports receiving consultant and/or medical advisory fees from Abbott Vascular, Bard Peripheral Vascular, Boston Scientific, Cardiovascular Systems Inc., Cook Medical, Medtronic, Spectranetics and Terumo. Katzen and Machan report financial ties with various medical device companies.