PROMISE I: Early feasibility study of the LimFlow System for percutaneous deep vein arterialization in no-option chronic limb-threatening ischemia: 12-month results.

OBJECTIVE: We report the 6- and 12-month outcomes of the PROMISE I early feasibility study after treatment of no-option chronic limb-threatening ischemia (CLTI) with percutaneous deep vein arterialization (pDVA) using the LimFlow System. METHODS: Thirty-two patients with no-option CLTI, previously offered major amputation, were enrolled in this single-arm early feasibility study of the LimFlow pDVA System. No-option CLTI was defined as being ineligible for surgical or endovascular arterial revascularization. Patients were assessed for clinical status, pain, wound healing, and duplex ultrasound at 30 days, 6 months, and 12 months post-treatment. Primary endpoint analysis was amputation-free survival (AFS) at 30 days and 6 and 12 months. AFS was defined as freedom from above-ankle amputation of the index limb and freedom from all-cause mortality. Secondary endpoints evaluated included technical success of the procedure, and wound healing at 6 and 12 months. RESULTS: Of 32 enrolled patients, 31 (97%) were successfully treated with the LimFlow System at the time of the procedure, and two (6.3%) were lost to follow-up. The 30-day, 6-month, and 12-month AFS rates were 91%, 74%, and 70% respectively. The wound healing status of fully healed or healing was 67% at 6 months, and 75% at 12 months. Reintervention was performed in 16 patients (52%) with 14 (88%) of the maintenance reinterventions occurring within the first 3 months. The majority of reinterventions (n = 12; 75%), involved the arterial inflow tract proximal to the stented LimFlow circuit, and no in-stent stenoses were determined to have been the cause of reintervention. CONCLUSIONS: The LimFlow pDVA System was utilized in treating patients with no-option CLTI. A high technical success rate was observed, with a significant percentage of patients surviving free of major amputation at 12 months. These results suggest early safety and provide an initial assessment of the efficacy of the LimFlow pDVA System that supports the expansion of carefully executed studies to determine whether this is a viable option that can be used in this critically disadvantaged and growing patient population.

Dissections After Infrainguinal Percutaneous Transluminal Angioplasty: A Systematic Review and Current State of Clinical Evidence.

Purpose: To systematically review the literature and extract information on the definitions, prevalence, implications, and treatment of dissections after infrainguinal balloon angioplasty, with a goal of summarizing current data and identifying gaps in knowledge to help direct future research. Materials and Methods: A systematic review was performed according to the PRISMA guidelines. Medline (PubMed), Scopus, and Cochrane CENTRAL databases were reviewed for prospective and retrospective studies reporting dissection identification, characterization, incidence, severity, and/or outcomes after infrainguinal balloon angioplasty up to January 30, 2019. The electronic search resulted in 288 studies. From these, 153 full-text articles were assessed, and 51 published from 1964 to 2018 were selected as relevant to this systematic review. Because of the significant between-study differences in lesion characteristics, reporting methods, and lack of core laboratory adjudication, the findings were summarized from each study, but the results were not pooled. Results: The mechanism of percutaneous transluminal angioplasty (PTA) consists of adventitial stretching, medial necrosis, and controlled dissection or plaque fracture. PTA-induced dissections can precipitate pathological high and low shear hemodynamic defects and have been implicated as a contributing factor in procedural complications as well as restenosis at the treatment site. The development of significant dissection after PTA often leads to the use of adjunctive therapies, including stent placement. Despite the ubiquitous nature of dissection after balloon angioplasty (incidence 7.4% to 84%), limited data are available to categorize dissections in the peripheral arteries and direct subsequent treatments to improve vessel patency. With the increased utilization of drug-coated balloon angioplasty, understanding the outcomes of postangioplasty dissection has become increasingly important, as the decision to treat dissections with additional strategies has therapeutic and economic implications. Conclusion: All post-PTA dissections in the femoropopliteal arteries may benefit from a treatment approach that ensures optimal hemodynamics with long-term durability in treated lesions. Further understanding the importance of postangioplasty dissections, along with the development of new technologies, will help optimize the patency of endovascular interventions.

Role of high shear rate in thrombosis.

Acute arterial occlusions occur in high shear rate hemodynamic conditions. Arterial thrombi are platelet-rich when examined histologically compared with red blood cells in venous thrombi. Prior studies of platelet biology were not capable of accounting for the rapid kinetics and bond strengths necessary to produce occlusive thrombus under these conditions where the stasis condition of the Virchow triad is so noticeably absent. Recent experiments elucidate the unique pathway and kinetics of platelet aggregation that produce arterial occlusion. Large thrombi form from local release and conformational changes in von Willebrand factor under very high shear rates. The effect of high shear hemodynamics on thrombus growth has profound implications for the understanding of all acute thrombotic cardiovascular events as well as for vascular reconstructive techniques and vascular device design, testing, and clinical performance.

Improving proximal fixation and seal with the HeliFx Aortic EndoAnchor.

Endovascular aneurysm repair (EVAR) transformed the therapy for aortic aneurysms and introduced an era of widespread use for endovascular procedures in a variety of vascular beds. Although dramatic improvements in acute outcomes drove the early enthusiasm for EVAR, a realization that the long-term integrity of the endoprostheses used for EVAR were sometimes inferior to the results obtained with open surgical reconstruction dampened enthusiasm for their use in low-risk and younger patients who mandated long-term follow-up. While early EVAR failure modes are often related to technical aspects of the implantation, late failures are often related to the implant migrating from its original longitudinal position or losing wall apposition in the face of continued aneurysmal dilatation. Migration, or the failure of longitudinal fixation, results in gradual loss of aortic approximation and the eventual repressurization of the aneurysm sac with its attendant risks of growth and rupture. The inability of stent- and barb-based endovascular fixation to resist aortic dilatation at the site of fixation also represents a late failure mode that can result in aneurysm rupture. A variety of endostaples or endoanchors designed to replicate the function of an interrupted aortic suture have been proposed and tested to varying degrees over the years. The device designed and produced by Aptus EndoSystems, now called the HeliFx Aortic EndoAnchor is the only independent endovascular fixation device that has achieved significant clinical usage and Food and Drug Administration approval. The experience with this device is now more than 5 years and it is approved for use in the broad market across both Europe and the United States. This article will review the engineering and design concepts underlying the HeliFx device as well as the in vitro and in vivo results using this device. Finally, a discussion of the potential for technical, procedural, and endograft innovation based on the availability of endovascular suturing will be reviewed.

Helical EndoStaples enhance endograft fixation in an experimental model using human cadaveric aortas.

OBJECTIVE: This study evaluated the contribution of Aptus EndoStaples (Aptus Endosystems, Sunnyvale, Calif) in the proximal fixation of eight endografts used in the endovascular repair of abdominal aortic aneurysms (EVAR). METHODS: Nine human cadaveric aortas were exposed, left in situ, and transected to serve as fixation zones. The Zenith (Cook, Bloomington, Ind), Anaconda (Vascutek, Inchinnan, Scotland, UK), Endurant (Medtronic, Minneapolis, Minn), Excluder (W. L. Gore and Associates, Flagstaff, Ariz), Aptus (Aptus Endosystems), Aorfix (Lombard Medical, Didcot, UK), Talent (Medtronic), and AneuRx (Medtronic) stent grafts were proximally deployed and caudal displacement force (DF) was applied via a force gauge, recording the DF required to dislocate each device ≥20 mm from the infrarenal neck. Measurements were repeated after four and six EndoStaples were applied at the proximal fixation zone, as well as after a Dacron graft was sutured at the proximal neck in standard fashion. Finally, a silicone tube was used as a control fixation zone to test the DF of grafts with EndoStaples in a material that exceeded the integrity of a typical human cadaveric aorta and provided a consistent substrate to examine the differential effect of variable degrees of EndoStaple implantation using zero, two, four, and six EndoStaples. RESULTS: In the cadaveric model, the mean DF required to dislocate the endografts without the application of EndoStaples was 19.73 ± 12.52 N; this increased to 49.72 ± 12.53 N (P < .0001) when four EndoStaples where applied and to 79.77 ± 28.04 N when six EndoStaples were applied (P = .003). The DF necessary to separate the conventionally hand-sutured Dacron graft from the aorta was 56 N. In the silicone tube model, the Aptus endograft without EndoStaples withstood 3.2 N of DF. The DF increased to 39 ± 3 N when two EndoStaples were added, to 71 ± 6 N when four were added, and to 98 ± 5 N when six were added. In eight of the 13 cadaver experiments conducted with four and six EndoStaples, the displacement occurred as a result of complete aortic transection proximal to the fixation site, indicating that aortic tissue integrity was the limiting factor in these experiments. CONCLUSIONS: The fixation of eight different endografts was increased by a mean of 30 N with four Aptus EndoStaples and by a mean of 57 N with six EndoStaples in this model. Endostaples can increase endograft fixation to levels equivalent or superior to that of a hand-sewn anastomosis. The application of six EndoStaples results in aortic tissue failure above the fixation zone, demonstrating fixation strength that exceeds inherent aortic integrity in these cadavers.

Future technologies to address the failed endoprosthesis.

Endovascular aneurysm repair (EVAR) has transformed therapy for aortic aneurysms and introduced an era of widespread use for endovascular procedures in a variety of vascular beds. While dramatic improvements in acute outcomes drove the early enthusiasm for EVAR, a realization that the integrity of the endoprostheses used for EVAR was significantly inferior to results obtained with open surgical reconstruction dampened enthusiasm for their use in low-risk patients and mandated long-term follow-up for EVAR patients. The future of EVAR as a primary approach to aortic aneurysm repair rests on development of technologies and techniques that can reproduce the foundations and, therefore, the results of open surgical reconstruction. Many of these technologies will be used initially to address the failing endoprostheses, but will have a larger role in their application as a primary component of EVAR.

The phase I multicenter trial (STAPLE-1) of the Aptus endovascular repair system: results at 6 months and 1 year.

OBJECTIVE: This phase I IDE study (STAPLE-1) evaluated the primary endpoints of safety (major device-related adverse events at 30 days) and feasibility (successful deployment of all endograft components) of the Aptus Endovascular abdominal aortic aneurysm (AAA) Repair System (Aptus Endosystems, Inc, Sunnyvale, Calif) to treat AAAs. METHODS: A prospective, single arm Federal Drug Administration (FDA) Phase I IDE study was performed. The Aptus endograft is a three-piece modular device with a flexible unsupported main body and two fully supported limbs in a 5.3 mm outer diameter (OD) (16F) delivery system for all iliac limbs and two of three main body sizes. The largest main body (29 mm diameter) is in a 6 mm (18 F OD) delivery system. EndoStaples measuring 4 mm (length) by 3 mm (diameter) designed to provide transmural graft fixation to the adventitia are applied independent of the endograft delivery system. Inclusion criteria included a proximal aortic neck length of 12 mm and iliac landing zone of 10 mm. Secondary endpoints included freedom from endoleaks, rupture, migration, and device integrity. RESULTS: Twenty-one (21) patients were enrolled at five centers. All patients received the Aptus Endograft and EndoStaples. Ninety-six EndoStaples (range, 2-10; median, 4) were implanted. All patients (n = 21) completed 1-month and 6-month follow-up evaluation and 14 completed 1-year follow-up. Two proximal cuffs and one limb extension were used as adjunctive endograft components at implantation. Three secondary interventions were performed in 2 patients for limb thrombosis. There were no EndoStaple-related adverse events, device integrity failures, migrations, or conversions. CONCLUSION: These results of the STAPLE-1 trial document the acute safety and feasibility of the Aptus Endograft and EndoStaples. Early follow-up demonstrates excellent 6-month and 1-year results. A pivotal phase II trial is underway at 25 US centers.

Endovascular repair of a common iliac artery aneurysm using the Cook Zenith abdominal aortic aneurysm Endovascular Graft Converter.

Isolated common iliac artery aneurysm is a rare condition that is treated aggressively because of its high risk of rupture. Endovascular abdominal aortic aneurysm (AAA) repair has recently been extended to the clinical management of the iliac artery aneurysm. Stent grafts have been used successfully to exclude iliac artery aneurysms. Successful graft deployment and aneurysm exclusion require adequate seal and fixation at the proximal and distal attachment sites. This article presents a high-risk surgical patient whose 6.8-cm-diameter iliac artery aneurysm was repaired with a Zenith AAA Endovascular Graft Converter (Cook, Bloomington, Indiana). This device is normally used to convert an aortobiiliac endograft to an aortouniiliac endograft during AAA repair. The tapered 80-mm-long graft has diameters of 24 mm proximally and 12 mm distally. Completion arteriogram demonstrated exclusion of the iliac artery aneurysm with no evidence of endoleak. No postoperative complications occurred. No endoleak was seen on the follow-up abdominal computed tomography scan.

Five-year interim comparison of the Guidant bifurcated endograft with open repair of abdominal aortic aneurysm.

OBJECTIVE: This study was undertaken to compare 1-year and 5-year results of endovascular repair of abdominal aortic aneurysm (AAA) with the Guidant/EVT bifurcated graft system with results of open repair. METHODS: This was a prospective, nonrandomized, concurrent controlled study that compared results of endovascular versus open repair of AAA. The Phase II study with the EGS delivery system included 268 patients in 18 US medical centers; and the Phase III trial with the Ancure delivery system incuded 305 patients in 21 US institutions. Data were internally and externally audited and subjected to periodic review by the US Food and Drug Administration. The control group of 111 patients were excluded from endovascular repair with a tube graft because of anatomic considerations, but were otherwise comparable to the experimental group. Patients in the control group underwent conventional open surgical repair concurrently with patients who underwent EGS repair in 18 US institutions. RESULTS: Five hundred thirty-one of 573 patients (92.7%) underwent successful implantation of the Guidant/EVT bifurcated endograft. The combined major morbidity and mortality in the endograft group was 28.8%, compared with 44.1% in the open control group. Additional benefits in the endograft group included shorter hospital stay (2 days vs 6 days), less surgical blood loss (400 mL vs 800 mL), and less intensive care unit use (33% vs 94%). These early results are reported on an intent-to-treat basis; in all patients an attempt was made to treat with the endovascular graft, including those patients in whom conversion to standard open repair was necessary during the primary procedure. Three hundred nineteen patients were selected for long-term follow-up to 5 years, on the basis of date of implantation; ie, patients with the earliest implantations were followed up for 5 years. The primary purpose of long-term follow-up was to obtain data on long-term efficacy of the graft; thus only patients in whom implantation was successful were selected. No patient has experienced an aneurysm rupture to date. Survival (Kaplan- Meier method) in the experimental group was 68.1%, compared with 77.2% in the control group (P = NS). At 60 months, 74.4% of patients (32 of 43) were free of endoleak. There were no type I or type III endoleaks remaining. Aneurysm sac diameter decreased or remained stable in 97.6% of patients (41 of 42) and increased in only 1 patient. During the course of long-term follow-up, post-procedural conversion to open repair was required in only 9 patients (2.8%). CONCLUSION: The EVT/Guidant bifurcated graft is effective in preventing AAA rupture, and long-term survival is comparable to that with open repair.

Current hospital costs and medicare reimbursement for endovascular abdominal aortic aneurysm repair.

OBJECTIVE: The purpose of this study was to analyze the current inpatient hospital cost and Medicare reimbursement of endovascular abdominal aortic aneurysm repair (EVAR) at different hospitals. METHODS: The cost of EVAR from October 2000 to October 2001 with two commercially available endografts (Ancure, Guidant Endovascular Solutions, Menlo Park, Calif; and AneuRx, Medtronic AVE, Santa Rosa, Calif) was retrospectively analyzed at seven hospitals. Three university (n = 111) and four community hospitals (n = 110) from different regions of the country participated in the survey. Consecutive cases with complete financial records were included. Hospital finance departments provided their best estimates of hospital costs, including overhead for operating room, endograft, medical supply, bed, radiology, laboratory, and pharmacy services and reimbursement on the basis of hospital-specific Diagnostic Related Groups (DRG) 110 or 111. Detailed hospital charges and International Clinical Diagnosis codes also were reviewed from Universal Billing-92 forms submitted to Medicare. An additional cost analysis was performed by the authors to validate the estimates of the hospital financial departments. Outliers of more than three standard deviations from the mean were excluded. RESULTS: The mean total hospital cost was $22,999, and mean reimbursement, weighted by case mix, was $20,837, resulting in a net loss of $2162. The majority of EVAR cost was from the device (57%) and other medical supplies (16%). EVAR was reimbursed on the basis of DRG 110 in 78% of cases and of DRG 111 in 22%. Reimbursement varied widely by hospital and location (mean, $20,837; range, $14,818 to $35,343; standard deviation, $5450). With the exclusion of one hospital where reimbursement was not based on the DRG, cases reimbursed with DRG 110 resulted in an average loss of $2200, while the average loss was $9198 with DRG 111. The mean net loss for hospitals reimbursed with the DRG system was $3898. CONCLUSION: EVAR reimbursement is presently inadequate to cover hospital expenses. Substantial financial losses occurred at four of the participating centers. University hospitals fared surprisingly better because of higher reimbursement.

Limb interventions in patients undergoing treatment with an unsupported bifurcated aortic endograft system: a review of the Phase II EVT Trial.

INTRODUCTION: Both supported and unsupported bifurcated endograft limbs develop flow-restricting lesions, including kinks, stenoses, and occlusions, which can be identified during or after surgery. Recognition and intervention are essential to achieve long-term graft patency and a satisfactory functional result. This report represents a comprehensive retrospective review of graft limb interventions from the Phase II EVT Trial with the Endovascular Grafting System unsupported bifurcated endograft (Guidant/EVT, Menlo Park, Calif). METHODS: The study population consists of 242 patients who underwent treatment with bifurcated endografts implanted during the EVT Phase II Trial. Graft limb interventions have been divided into two groups: those in whom the intervention occurred during surgery versus those in whom the intervention occurred after surgery. Parameters studied included type, incidence, and timing of graft limb intervention, indications for intervention, procedures performed, and overall patient outcome. RESULTS: The mean follow-up period was 31 months. Primary, primary assisted, and secondary limb patency rates were 61.6%, 93.7%, and 97.1%, respectively. Technical success rate at case completion was 97.5%. In 68 of the 242 cases, limb interventions were performed during surgery to assure patency (28.1%). In 28 cases, interventions were performed after surgery (11.6%). Of these postoperative limb problems, 82% occurred during the first 6 months. Repeat limb interventions were necessitated in three patients (1.2%). Within the intraoperative intervention group, perceived indications included kinks (15%), stenosis (57%), dissection (6%), graft redundancy (12%), and instances of twists, thrombosis, and pressure gradients (10%). These findings were successfully managed with percutaneous transluminal angioplasty only (41%), percutaneous transluminal angioplasty and stent (50%), and various combined interventions. Within the postoperative intervention group, symptomatic indications included stenosis (46%) and thrombosis/occlusion (54%). These postoperative limb events were successfully managed with stent (64%), thrombolysis (32%), and femoral-femoral bypass (21%). When limb dysfunction developed in the postoperative setting, it most often occurred within the first 6 months of implantation. Only one patient in this Phase II cohort had a lower extremity amputation unrelated to a graft limb abnormality. CONCLUSION: The unsupported bifurcated limbs of this endograft necessitated primary adjunctive intervention in 40% of cases. Primary intervention was two times more likely to be performed at the time of the implant rather than after surgery. Repeat limb interventions were not common. Endograft limb flow problems were successfully treated with standard endovascular or surgical interventions or both. These data may support prophylactic stenting of unsupported Ancure graft limbs. A strategy that includes both intraoperative and early postoperative graft limb surveillance is essential to detect reduced limb flow.

Endoleak: predictive value for aneurysm growth at 3 years.

Endoleak is a unique radiographic finding after endovascular aneurysm repair. The prognostic implication of endoleak on aneurysm therapy outcome is unknown. Patients with 3 years of follow-up were examined to determine the predictive value of endoleak, as determined by the treating physician, for aneurysm growth. Patients enrolled in a clinical trial for a unibody, bifurcated endovascular graft (Ancure-Guidant/EVT, Menlo Park, CA) were examined with respect to endoleak, as determined by the primary investigator, and aneurysm diameter change. A total of 80 patients were available at 3 years for evaluation. CT scans and ultrasound were used to determine endoleak at discharge, at 6 months, and annually. Patients were categorized as no leak (NL; n = 59), early leak (EL, leak identified by 6 months; n = 15), and late leak (LL, leak identified at 12 months or later; n = 6). A change of 5 mm in transverse diameter relative to the original diameter was used to determine an increase or decrease. Therapeutic intervention for endoleak was analyzed separately in each group. From the results we were able to determine that most patients with distal type 1 or type 2 endoleak have shrinking or stable aneurysms. Endoleak is a poor predictor of aneurysm growth but is statistically associated with enlargement. Absence of endoleak is strongly, but not entirely, predictive of lack of aneurysm growth. Endoleak is a risk factor for aneurysm enlargement, warranting further investigation to examine the etiology of the image, but cannot be used as an endpoint for effective endovascular aneurysm treatment.