Abstract
Now in its 9th year, the Vascular Interventional Advances (VIVA) Symposium has demonstrated comprehensive, objective, cutting-edge continuing education in the field of vascular medicine and intervention. With a faculty representing expertise across all specialties, and using a proprietary system of interactive educations (Laptop Learning), attendees listen to presentations and debates, and watch cases demonstrating state-of-the-art interventions from sites around the world. This year, VIVA attracted some of the most important studies presented by international investigators. In this article details regarding new stent technologies in the aorta, peripheral artery and carotid arteries will be highlighted.
3-year RESILIENT trial data
Barry T Katzen (Baptist Cardiac & Vascular Institute of Miami, FL, USA) presented a 3-year follow-up of the prospective, multicenter RESILIENT trial. RESILIENT compared the results of percutaneous transluminal angioplasty (PTA) versus self-expanding Nitinol stent deployment (Lifestent®, Bard Peripheral Vascular, AZ, USA) in patients with symptomatic atherosclerotic peripheral artery disease (PAD) from superficial femoral artery (SFA) disease. The 12-month data have been published, revealing a dramatic improvement in primary patency and avoidance of target lesion revascularization (TLR) among patients receiving the stent Citation[1]. The 3-year follow-up demonstrates persistent benefit of the Lifestent over PTA (freedom from TLR [stent 75.5%; PTA: 41.8%; p < 0.0001] and clinical success [stent 63.2%; PTA: 17.9%; p < 0.0001]). Finally, the stent fracture rate was 3.1% at 12 months, increasing only to 4.1% at 36 months. Stent fractures were reported using a standardized grading scale, and were analyzed by an independent core laboratory Citation[2]. These data support the initial strategy of Nitinol stent deployment over the use of PTA alone for patients with symptomatic PAD requiring revascularization.
Interim analysis of the DURABILITY II study
Data regarding the role of stents for treatment of symptomatic PAD continue to improve. Krishna Rocha-Singh (Prairie Cardiovascular Consultants, Ltd., IL, USA) presented an interim analysis of DURABILITY II. This was a prospective, multicenter, single-arm registry of the EverFlex™ Nitinol stent (Covidien/eV3, MA, USA), reporting outcomes compared with a series of performance goals established by the Vascular Interventional Advances (VIVA) group Citation[3]. The mean lesion length within the SFA group was 10.96 cm. The total cohort included 287 patients, but this interim analysis reported 164 patients, all of which received a single stent. Patency as determined by duplex ultrasonography at 12 months was 69.5% (patency defined by peak systolic velocity ratio <2.0). Only one stent fracture was noted. A subgroup of 20 patients underwent baseline and 1-year measured walking distance using a graded treadmill and demonstrated a significant increase in absolute claudication distance of 177 ± 515 m. We are eagerly awaiting the final report to determine if the EverFlex stents meet the VIVA performance goal; however, the interim data certainly look encouraging.
3-year VIBRANT trial data
Gary Ansel (Riverside Methodist Hospital, OH, USA) presented 3-year data from the VIBRANT trial, which included 148 patients randomized to the original Viabahn® device (WL Gore, AZ, USA) or bare Nitinol self-expanding stents for the treatment of long-segment SFA disease. The mean lesion lengths were 19 cm in the Viabahn group and 18 cm in the bare Nitinol stent group. Three-year primary patency rates decreased in both groups, however, in the Viabahn arm, primary patency decreased from approximately 48% to approximately 23%. Freedom from TLR was comparable in both groups at both 12 and 36 months of follow-up. The VIBRANT investigators hypothesized that the pattern of in-stent restenosis explains this finding, as bare Nitinol stents tended to demonstrate long, diffuse in-stent restenosis, while the Viabahn device demonstrated focal edge in-stent restenosis. It is worthwhile to note that stent fractures were infrequent in the Viabahn device (4.9%) when compared with the bare Nitinol stent group (58%).
1-year VIPER trial results
The VIPER trial studied the impact of the heparin-bonded, fabric-covered, edge-contoured, self-expanding Nitinol stent – the Viabahn device – and the data were presented by Richard Saxon (North County Radiology Medical Group, CA, USA). One hundred and nineteen patients were included in this report, with lesion lengths comparable to VIBRANT (19 cm). A total of 56% of lesions represented occlusions. Primary patency was 74%, with primary assisted patency improving to 87%. Interestingly, there was no difference in primary patency among lesions that were <20 cm compared with those that were >20 cm; however, larger diameter devices (i.e., 7 mm) demonstrated a trend towards improved patency compared with smaller diameter devices (i.e., 5 mm); nevertheless these numbers are small. Finally, oversizing of the device, particularly in the proximal aspect of the SFA, resulted in worse patency than if the device was not significantly oversized. When compared with the VIBRANT trial – in which the Viabahn device was not available in 7 mm diameters and did not have a contoured edge or heparin bonding – the primary patency of similar lesion lengths was 17% higher.
PACIFIER trial
There has been intense interest in drug-eluting balloons (DEB) since the publication of the THUNDER trial Citation[4]. Michael Werk (Martin Luther Hospital, Berlin, Germany), presented the results of a prospective randomized trial of a paclitaxel-coated balloon angioplasty catheter (InPact Pacific DEB, Medtronic Invatec, CA, USA) compared with a bare PTA balloon in patients with symptomatic femoropopliteal PAD. Ninety one patients were randomized (44 to DEB), with only a minority (4–5%) suffering from critical limb ischemia (CLI). The mean lesion length was 7.0 cm in the DEB arm and 6.6 cm in the PTA arm. The primary end point, angiography-based late lumen loss, was virtually absent in the DEB arm, while the late lumen loss was 0.61 in the PTA arm (p = 0.003). The composite safety end point of TLR, amputation and death was statistically higher in the PTA arm. This study continues to fan the flames of enthusiasm regarding the potential role of DEB in PAD.
6-month DEFINITIVE LE results
Atherectomy has been challenged by relatively limited scientific data Citation[5]. Lawrence A Garcia (St Elizabeth’s Medical Center, MA, USA) presented the 6-month results of a prospective, multicenter registry of 800 patients with symptomatic PAD enrolled in the USA and Europe, all treated with the SilverHawk™ and TurboHawk™ atherectomy catheters (Covidien/eV3, MA, USA). Although the majority of patients had claudication, 25% had CLI. The mean lesion length was 7.4 ± 5.3 cm. At 6 months, primary patency among claudicants was 87.6%, and freedom from amputation among patients with CLI was 97.3%. Interestingly, there was no difference in patency in patients with diabetes mellitus, and no trend suggesting significant worsening of patency in longer lesions (i.e., >10 cm). If residual stenosis (<30%) was noted following primary atherectomy, additional treatment did not offer any advantage in primary patency. This represents the most robust data set of atherectomy to date, and we look forward to further data as patients continue to be followed prospectively.
Results of the PROOF study
On the heels of the recently published CREST trial Citation[6], the role of carotid artery stenting (CAS) is highly controversial. Sumaira Macdonald (Freeman Hospital, UK) presented results of a novel carotid artery stent system. Many believe that the neurological events that occur during CAS are due to catheter manipulation of the aortic arch, resulting in atheromatous embolization. In the PROOF study, the MICHI system (Silk Road Medical, CA, USA) was used in 65 patients, the majority of whom were asymptomatic (82%). The MICHI system utilizes direct surgical exposure of the proximal common carotid artery, placement of an 8 F arterial sheath, and initiation of an arteriovenous shunt circuit, which results in retrograde flow away from the brain. Blood returns via an 8 F transfemoral venous sheath. This ‘proximal protection’ theoretically minimizes the risk of cerebral embolization during CAS. All patients tolerated flow reversal, and 61 patients completed 30-day follow-up. No patient suffered the composite primary end point of major stroke, myocardial infarction, or death. One patient had a contralateral minor stroke, and one patient experienced cranial nerve injury. Forty eight patients underwent diffusion-weighted MRI before and within 48 h of the procedure. New lesions were identified in 16.7% of patients, which is comparable to a cohort who underwent carotid endarterectomy in a different trial. The ROADSTER trial is a US-based large-scale study planned using this technology in similar patient cohorts.
Abdominal aortic endograft advances
Ovation stent graft: results of the Pivotal trial
Endografts for the treatment of abdominal aortic aneurysms (AAA) have become the primary treatment for many patients Citation[7]. Manish Mehta (Institute for Vascular Health and Disease, NY, USA) presented the results of the first of two trials at Vascular Interventional Advances 2011 of novel endograft technology for the treatment of AAA. The Ovation® stent graft (Trivascular, CA, USA) was studied in 161 patients with AAA of 5.0 cm or greater in diameter or, if less than 5.0 cm, had demonstrated rapid expansion in size. This device has the smallest diameter designed to date. Patient attributes included 46% with known coronary artery disease and over 85% with a history of active or recently discontinued tobacco use. All procedures were technically successful, and through 2 years of follow-up, no patient developed a type I/III endoleak (arterial flow developing in the previously treated AAA), suggesting durable fixation and sealing of the AAA. In the same follow-up period, no patient suffered aneurysm rupture or conversion to open surgical repair.
Initial results of the worldwide ENGAGE registry
Following Mehta’s presentation, Marc Schermerhorn (Beth Israel Deaconess Medical School, MA, USA) presented the early results of the international ENGAGE Registry using the modular Endurant™ stent graft system (Medtronic, CA, USA). One thousand two hundred patients with AAA from 79 sites on six continents were included. Over 99% of devices were successfully implanted. Within 30 days, the major adverse event rate was 4.3%, but only 1.4% had type I or III endoleaks. Aneurysm-related mortality was 1.9% at 1 year, and 97% of patients demonstrated stable or diminished aneurysm size at 1 year. No patients suffered a type I endoleak at 1 year, and no device actually migrated from its original position.
Results of the ZEN trial
In the most novel presentation at VIVA 2011, Jason Rogers (UC Davis Medical Center, CA, USA) shared the results of the first-in-man trial of a zotarolimus-coated balloon expandable stent for treatment of erectile dysfunction (ED) in men where phosphodiesterase-5 inhibitors (Medtronic Vascular, CA, USA) have failed. It is estimated that 30 million men suffer from ED, and the etiology is vascular in 80% of cases. Up to 75% of men with ED have associated atherosclerotic cardiovascular disease. Thirty men with erectile dysfunction and evidence of internal pudendal artery stenosis underwent stent placement. The International Index of Erectile Function was used to grade the effect of stent deployment on ED. No serious adverse events occurred, and 22 out of 30 patients experienced a significant improvement in erectile function. Sixty eight percent of patients noted a marked improvement in their International Index of Erectile Function score at 3 months. This preliminary data may result in a larger study of 350 patients at 15 clinical sites.
Summary
These data demonstrate the rapid expansion of quality scientific studies across a broad array of vascular conditions. Over 2000 attendees observed the continued iteration of minimally invasive therapies being developed and studied.
Author’s note
Devices mentioned in this manuscript may not be available for use in the USA. In addition, the devices in these trials may be used in an ‘off-label’ manner if they have received US FDA approval. The author is not recommending use of any devices mentioned in this manuscript, and has received no compensation from any sponsor or entity in preparation of this manuscript.
Financial & competing interests disclosure
MR Jaff is a board member at VIVA Physicians, a 501 (c) 3 not-for-profit education and research organization. MR Jaff is also a noncompensated advisor at Abbott Vascular, Cordis Corporation, Covidien and Medtronic Vascular, and is a consultant at Trivascular, Inc. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.
References
- Laird JR, Katzen BT, Scheinert D et al. Nitinol stent implantation versus balloon angioplasty for lesions in the superficial femoral artery and proximal popliteal artery. Twelve-month results from the RESILIENT randomized trial. Circ. Cardiovasc. Interv.3, 267–276 (2010).
- Jaff MR, Dake MD, Popma JJ, Ansel G, Yoder T. Standardized evaluation and reporting of stent fractures in clinical trials of non-coronary devices. Cathet. Cardiovasc. Interv.70, 460–462 (2007).
- Rocha-Singh K, Jaff MR, Crabtree TR, Bloch DA, Ansel G. Performance goals and end point assessments for clinical trials of femoropopliteal bare Nitinol stents in patients with symptomatic peripheral arterial disease. Cathet. Cardiovasc. Interv.69, 910–919 (2007).
- Tepe G, Zeller T, Albrecht T et al. Local delivery of paclitaxel to inhibit restenosis during angioplasty of the leg. N. Engl. J. Med.358, 689–699 (2008).
- Yancey AE, Minion DJ, Rodriguez C, Patterson DE, Endean ED. Peripheral atherectomy in TransAtlantic InterSociety Consensus type C femoropopliteal lesions for limb salvage. J. Vasc. Surg.44, 503–509 (2006).
- Brott TG, Hobson RW, Howard G et al. Stenting versus endarterectomy for treatment of carotid-artery stenosis. N. Engl. J. Med.363, 11–23 (2010).
- Greenhalgh RM, Brown LC, Powell JT, Thompson SG, Epstein D; United Kingdom EVAR Trial Investigators. Endovascular repair of aortic aneurysm in patients physically ineligible for open repair. N. Engl. J. Med.362, 1872–1880 (2010).