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The Take Home: ISET
Photo courtesy of Solares Photography
The 26th annual International Symposium on Endovascular Therapy (ISET) meeting was held in Miami Beach this past January. Attending the 5-day conference were Edward C. Miner, MD, FACC, interventional cardiologist at the Intermountain Heart Institute, Salt Lake City, and Michael R. Jaff, DO, chair of the Institute for Heart, Vascular and Stroke Care at Massachusetts General Hospital, Boston, who shared their thoughts on the highlights from the meeting.
Edward C. Miner, MD, FACC
Peripheral Intervention Takes Center Stage
ISET brings together physicians from different specialties and countries for an enjoyable and educational conference each year. Live cases and discussions covered everything from basic topics to future anticipated technologies in the field of endovascular intervention. One of the appealing things about ISET is the relatively small and intimate size of the conference — this facilitates informal discussion with colleagues that can be as valuable as the formal conference content.
Cutting-Edge Research
Edward C. Miner
In a late-breaking trial session, 4-year data from the Zilver PTX Randomized Controlled Trial of Paclitaxel-Eluting Stents for Femoropopliteal Disease were presented. This study enrolled 469 patients to evaluate the only currently approved peripheral drug-eluting stent in the United States. Patients who received the Zilver PTX stent demonstrated 75% primary patency at 4 years compared with only 57.9% primary patency for patients receiving provisional bare-metal stent placement, a 41% reduction in restenosis. These findings confirmed sustained, durable benefits and less need for costly repeat procedures. It supports the idea that DES technology can help significantly in the femoropopliteal vascular bed that is so prone to restenotic events, and that the increased up-front cost of drug-eluting technologies is likely justified if these technologies can prevent more expensive and complex reinterventions in a significant percentage of patients.
Also presented in the late-breaking trial session were 3-year data from the STROLL (S.M.A.R.T. Nitinol Self-Expanding Stent in the Treatment of Obstructive Superficial Femoral Artery Disease) study. This multicenter, nonrandomized study examined blockages in 250 patients that averaged 7.7 cm in length. Chronic occlusions were present in 23.6% of patients. Three years later, 72.7% of arteries were still patent. Also important, stent fractures were very rare (3.6%) and were all mild, not being associated with occlusion of the artery.
In another session at ISET, the Esprit BVS study was presented, which was a small study of 35 patients treated with a polylactide absorbable vascular scaffold. The scaffold demonstrated good procedural success, with an average of 80% stenosis reduced to just 13% after stent placement. At 6 months, 34 out of 35 patients still had patent stents and 29 patients had no significant claudication symptoms. Obviously, longer-term follow-up will be needed regarding this technology, but absorbable stent technology is appealing as it might avoid “burning” surgical options, as well as inflammation and restenosis associated with permanent stent placement.
The Zilver PTX, Esprit and STROLL studies all confirm the clinical impression of most peripheral interventionalists that stent placement is preferable to angioplasty alone in the majority of cases to prevent costly reintervention. These results add to the hope that both drug-eluting and absorbable scaffolds represent promising technologies for improving long-term outcomes in the femoropopliteal arterial system.
Renal Denervation
Also discussed heavily at ISET was catheter-based renal denervation, which has been much anticipated by peripheral interventionalists as a novel treatment that could help millions of patients with resistant hypertension, HF and even sleep apnea. Preliminary nonrandomized studies had shown impressive, sustained improvements in BP following this procedure.
Although no new renal denervation data were presented at ISET, the surprising announcement by Medtronic just before the meeting that the SYMPLICITY HTN-3 trial examining renal denervation in treatment-resistant hypertension failed to meet its primary efficacy endpoint was a hot topic of discussion. Results of this study were much anticipated, and most observers expected the study to prove the procedure’s efficacy and lead to approval of this technology.
This news once again underscores the importance of waiting for well-designed, randomized trials prior to “irrational exuberance” and widespread adoption of new technologies. Nonrandomized studies had suggested large reductions in BP with this technology, but this result teaches us that more thorough evaluation regarding appropriate patient populations and ablation techniques are still necessary.
More complete details regarding this study are planned at the American College of Cardiology Scientific Sessions meeting in March. Most ISET attendees felt that different renal denervation technologies still deserve clinical evaluation, and that through different technologies and perhaps different study designs (pertaining to patient selection and antihypertensive medication management), renal denervation will still be an important future technology in addressing the very common clinical problem of resistant hypertension.
Michael R. Jaff, DO
Opening Town Hall
Michael R. Jaff
The opening town hall meeting at ISET addressed the controversial topic of renal denervation, right on the heels of the Medtronic press release. Barry T. Katzen, MD, revamped the session to reflect the breaking news about SYMPLICITY HTN-3 and Martin B. Leon, MD, gave a phenomenal presentation on the topic. Dr. Leon provided his broad perspective on the field of renal denervation, the challenges of performing large-scale randomized trials and the need for caution until we see the actual data from SYMPLICITY HTN-3.
Although it’s tempting to draw conclusions on renal denervation based on the press release, we have to keep in mind that none of us know what the data show yet. More than likely, there will be a lot of people talking about flaws in trial design, that the chosen endpoint was too aggressive and so on. As of now, many people have either made judgments about where the field is going or have given up on it entirely, but I think it is premature to do either until we see the data and understand why the trial failed. The question for future renal denervation trials is whether FDA regulators will allow the design to be tweaked or if they are going to demand that this is the only type of pathway for US approval. Again, it’s too soon to make that statement until we know exactly what happened in the trial.
Live Physical Exam
Also at ISET, I performed a live physical exam on a patient who had significant peripheral vascular disease. You don’t see this at national or international meetings very often. In fact, this is the first time I have ever seen a patient with peripheral vascular disease come to be examined in front of a live audience. Last year, we did a similar session, but the person I examined was a normal, healthy young person, and it was done primarily to show how to perform an exam.
For the most recent exam, they had a hand-held camera showing live what I was doing and people were making comments about how to feel pulses and do a Doppler exam. The room was packed and I think people really got a kick out of it. To my surprise, there were many mid- to senior-career physicians who were there and entirely engaged, and not solely those who were in training or just out of training, which is what I had anticipated.
One of the particularly interesting facets to this is that physicians tend to view physical exams as a lost art and often order many imaging tests like CT scans and MRI instead. However, actually laying hands on a patient and trying to figure out what’s going on before you actually do it is really important. I found things on the physical exam that the physicians and patient were not fully aware of, which really drove the point home that there are a lot of advantages to doing physical exams.