Device Instructions For Use Research Articles

PS10 Adherence to EVAR Device Instructions-for-Use (IFU) Guidelines Has No Impact on Long-Term Outcomes

Adherence to EVAR Device Instructions for Use (IFU) Guidelines Has No Impact on Long-Term Outcomes Joy P. Walker, MD, Lue-Yen Tucker, Philip Goodney, Hong Hua, Steven Okuhn, Ann Rhoades, Bradley Hill, Robert W. Chang. Vascular and Endovascular Surgery, University of California San Francisco, San Francisco, Calif; Kaiser Permanente Division of Research, Oakland, Calif; Dartmouth-Hitchcock Medical Center, Lebanon, NH; The Permanente Medical Group, San Francisco, Calif; Kaiser Permanente, Oakland, Calif; The Permanente Medical Group, Santa Clara, Calif; The Permanente Medical Group, South San Francisco, Calif

Comparison of attachment site endoleak rates in Dacron versus native aorta landing zones after thoracic endovascular aortic repair

Type I attachment site endoleaks are the most common cause for reintervention after thoracic endovascular aortic repair (TEVAR) and represent treatment failures. Deployment of endografts in segments of the aorta previously replaced with Dacron grafts may be associated with reduced type I endoleak due to mechanical stability and decreased potential for aortic remodeling. However, no study has rigorously examined endoleak rates in Dacron landing zones vs native aorta. A retrospective analysis of a prospectively maintained database was performed to identify all patients undergoing TEVAR at a single referral institution between May 2002 and June 2012. Overall, 319 patients undergoing 345 procedures had at least one follow-up contrast-enhanced computed tomography scan to assess for postoperative type I endoleak. Attachment site landing zones were classified as native aorta, Dacron, or endograft if landed in a previously placed endograft. Patient characteristics and type I endoleak rates were compared among the three groups. Identified were 697 proximal or distal landing zones (native aorta, 599; Dacron, 79; and endograft, 19). Patients with at least one Dacron landing zone had higher rates of hypertension (P < .01), chronic obstructive pulmonary disease (P = .04), and prior aortic surgery (P < .01) and were more likely to have undergone complex hybrid repairs (P < .01). Cumulative type I endoleak rates were equivalent between the three types of landing zone (native aorta, 3.7%; Dacron, 2.5%; endograft, 0%; P = .44). Two type I endoleaks occurred with Dacron landing zones in the first tertile of TEVAR experience and with Dacron landing zone lengths of <2.5 cm. Evaluation of endoleak rates by tertile of experience demonstrated decreased type I endoleak rates in Dacron landing zones between the first and second/third tertiles of experience (13.3% vs 0%, P = .03) after a policy of using >4 to 5 cm (twice the device instructions for use) of Dacron overlap was initiated. Endograft deployment within long-segment (landing zone length of >4-5 cm) Dacron represents a durable option for aortic repair and was associated with a 0% rate of type I endoleak. In cases of a borderline native aortic landing zone, a hybrid procedure to create an adequate Dacron landing zone may be warranted to decrease the risk of type I endoleak and treatment failure.

One-Year Outcomes from an All-Comers Chinese Population of Patients Implanted With the Resolute Zotarolimus-Eluting Stent

The RESOLUTE China Registry is a prospective, multicenter, all-comers, observational study of patients in China implanted with the Resolute zotarolimus-eluting stent (R-ZES). R-ZES was commercially available before the enrollment began. All patients suitable for R-ZES implantation according to applicable guidelines were candidates for enrollment at 30 centers and were treated per standard hospital practice. Dual antiplatelet therapy (DAPT) was prescribed for a minimum of 6 months per current European Society of Cardiology guidelines and the device instructions for use. There were 1,800 patients enrolled with a mean age of 61.3 ± 10.9 years, 76% of patients were men, and 61% had complex disease. DAPT use was 94% at 1 year. Target lesion failure (cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization) at 1 year was 3.5% (95% confidence interval 2.7% to 4.5%). The rate of cardiac death was 0.6%, target vessel myocardial infarction 2.3%, and clinically driven target lesion revascularization 0.9%. The 1-year rate of definite or probable stent thrombosis was 0.5% (8 of 1,750); 0.4% (7 of 1,750) occurred early (0 to 30 days) and 1 event occurred late (1 to 12 months). One stent thrombosis occurred in a patient who had an interruption of DAPT within the first month; all other stent thromboses occurred while on DAPT. Outcomes did not differ significantly between monitored and unmonitored patients (difference in target lesion failure, p = 0.264). In conclusion, the RESOLUTE China Registry confirms the safety and effectiveness of R-ZES in a large real-world Chinese population.

The Morphological Applicability of a Novel Endovascular Aneurysm Sealing (EVAS) System (Nellix) in Patients with Abdominal Aortic Aneurysms

Endovascular aneurysm sealing (EVAS) using the Nellix system is a promising alternative to endovascular repair (EVR) and open surgery for abdominal aortic aneurysms (AAA). The aim of this study was to investigate the proportion of patients with AAA who are morphologically suitable for treatment with Nellix. Patients presenting with AAA were investigated at two regionalised vascular units. Separate cohorts were identified, who had undergone infrarenal EVR, open aneurysm repair, fenestrated endovascular repair (FEVR) or non-operative management. Pre-operative morphology was quantified using three-dimensional computed tomography according to a validated protocol. Each aneurysm was assessed for compliance with the instructions for use (IFU) of Nellix 776 patients were identified with mean age 75 ± 9 years. 730/776 (94.1%) had undergone infrarenal EVR, 6/776 (0.8%) open repair, 27/776 (3.5%) FEVR and 13/776 (1.7%) had been managed non-operatively. 544/776 (70.1%) of all AAA were morphologically suitable for Nellix. 533/730 (73.0%) of patients who had undergone infrarenal EVR were compliant with Nellix IFU, compared with 497/730 (68.1%), 379/730 (51.9%) and 214/730 (29.3%) with the IFU for Medtronic Endurant (p = .04) or Cook Zenith (p < .01) and Gore C3 Excluder (p < .01) endografts respectively. Nellix technology appears widely applicable to contemporary infrarenal AAA practice, and may provide an option for patients that are outside current EVR device instructions for use. However, formal outcomes study is still required, and will ultimately dictate the clinical relevance of this feasibility study. The major limitation to anatomic suitability for Nellix is currently the maximum patent lumen diameter of large AAA.

Outcomes Following Endovascular Abdominal Aortic Aneurysm Repair Both Within and Outside of the Instructions for Use

To determine the influence of the abdominal aortic aneurysm (AAA) anatomy on the clinical outcomes after endovascular AAA repair (EVAR). Between January 2008 and December 2010, 53 patients underwent EVAR. The parameters outside of the device instructions for use (IFU) were: short neck length (<15 mm), proximal neck angulation (>60 degrees), small diameter of external iliac artery (<7 mm) and bilateral internal iliac embolization. A total of 37% of these grafts were placed outside of at least one IFU parameter. The intraoperative problems encountered included one (3%) acute graft limb thrombosis, and one (3%) access vessel rupture within the IFU (w-IFU) group. One perioperative mortal case was observed in the w-IFU group due to thoracic aortic dissection. After one year follow-up, type II endoleak (EL) was recognized in 8 of 28 (29%) patients in the w-IFU group, and in 2 of 12 (17%) patients outside of the IFU (o-IFU) group. There was also no significant difference of early and mid-term outcomes between favorable neck anatomy and hostile neck anatomy (HNA). In our series, EVAR provided acceptable results even in the o-IFU group and HNA. This suggests that the IFU can be extended to other selected patients.

Two Decades of Endovascular Abdominal Aortic Aneurysm Repair: Enormous Progress With Serious Lessons Learned

The modern open surgical management of abdominal aortic aneurysm (AAA) has changed little since its inception in the 1950s. Endoaneurysmorrhaphy, first described by Rudolph Matas in 1888, involved ligating the branches of an aneurysm from within the aneurysm sac. Approximately 25 years later at the

Predictors of Abdominal Aortic Aneurysm Sac Enlargement After Endovascular Repair

Conclusion: In the Unites States compliance with endovascular aneurysm repair (EVAR) device guidelines is low. Rates of post-EVAR aneurysm sac enlargement are high. Summary: Companies marketing EVAR devices measure technical factors such as delivery accuracy, sealing ability, and fixation strength in the laboratory. These measurements are used to generate instructions for use (IFU) that are packaged with each EVAR device sold in the United States. The randomized trials comparing EVAR with open aneurysm repair have used EVAR devices in accordance with IFUs. Many physicians may perform EVAR without adherence to IFUs. It is unknown how often EVAR is performed outside the IFU for the device and longer-term results of EVAR performed outside IFUs are unknown. However, a significant portion of late deaths after EVAR are due to aneurysm rupture (De Bruin JL et al, N Engl J Med 2010;362;1881-9, and Wyss TR, Ann Surg 2010;252;805-12) and aneurysm rupture after EVAR is linked with aneurysm sac enlargement. The authors sought to determine compliance with IFUs in EVAR placement over the last decade and to determine relationships between anatomic characteristics at baseline of aorta and iliac arteries and the subsequent incidence of aortic aneurysm sac enlargement after EVAR. The authors examined patients undergoing EVAR between January 1, 1999, and December 31, 2008, using a medical imaging repository at M2S, Inc. (West Lebanon, NH). The deidentified data on all patients in the prospectively acquired M2S database was used for those who underwent a CT scan before EVAR and had at least one CT scan after EVAR between 1999 and 2008 in the United States. Patients were excluded if they underwent an EVAR in the context of premarketing or postmarketing studies in which M2S served as a core imaging laboratory. Preoperative aorta iliac anatomic characteristics were reviewed for each patient. The specific endovascular device implanted was not available from this database. Morphologic measurements were therefore compared with the most liberal and most conservative published anatomic guidelines stated in manufacturer's IFUs. Primary outcome was post-EVAR aneurysm sac enlargement >5 mm. There were 10,228 patients included in the database and used for the study. Of these, 59% had a maximum abdominal aortic aneurysm diameter below the 55-mm threshold at which intervention is recommended over surveillance. Forty-two percent of patients had anatomy that met the most conservative definition of IFUs and 69% met the most liberal definition of device IFUs. The 5-year post-EVAR rate of AAA sac enlargement was 41%. Independent predictors of AAA sac enlargement included age >80 years, endoleak, aortic neck diameter >28 mm, aortic neck angle >60°, and common iliac artery diameter >20 mm. Comment: Some physicians placing EVAR devices may be acting in what some could consider an irresponsible fashion. In this study, most EVAR devices were placed in abdominal aortic aneurysms that were below the threshold for intervention justified by randomized trials. Even with the most liberal definition of IFUs almost one-third of devices were placed outside manufacturer's recommendations, and in this database, >40% of aortas treated with EVAR had aneurysm sac enlargement at 5 years. The data are disturbing and raise significant questions about aneurysm treatment in the United States and about long-term risk of aneurysm rupture in patients treated with EVAR in the United States. Physicians placing EVAR devices need to do better job of policing themselves. If not, one can be sure someone else will! One can only speculate that it won't take long for the malpractice attorneys to stumble on to this.

The influence of gender and aortic aneurysm size on eligibility for endovascular abdominal aortic aneurysm repair

The purpose of this study was to compare the eligibility of men and women with infrarenal abdominal aortic aneurysms (AAAs) for on-label endovascular aneurysm repair (EVAR) as part of the clinician-Food & Drug Administration (FDA) collaborative effort, the Characterization of Human Aortic Anatomy Project (CHAP). Computed tomography (CT) scans with 3D reconstruction from a single institution obtained between July 1996 and December 2009, including standardized measurements by a blinded third-party (M2S, West Lebanon, NH) were examined. For inclusion, abdominal aortic aneurysm (AAA) had to be infrarenal, unrepaired, and >5 cm, or 4 cm to 5 cm if the orthogonal sac diameter was more than twice the aortic diameter at the renal level. Scans were included regardless of subsequent EVAR, open repair, or lack of treatment. One thousand sixty-three unique, unrepaired AAAs were analyzed. Neck length, diameter, and angulation differ for women (P < .001) even after adjustment for patient age and AAA size. EVAR eligibility based on device Instructions for Use (IFU) criterion is affected by gender. Neck length <15 mm was found in 47% of men and 63% of women. Neck angulation exceeding 60 degrees was found in 12% of men and 26% of women. Minimum iliac diameter of 6 mm was found in 35% of men and 55% of women. Only 32% of men and 12% of women met all three neck criterion and had iliac lumen diameters >6 mm. Logistic regression modeling shows that older patient age (odds ratio [OR], 0.84 per decade), increased aneurysm diameter (OR, 0.70 per cm), and female gender (OR, 0.4) are each independently associated with decreased odds of meeting all device IFU neck criterion (P < .05). EVAR eligibility by neck criterion does not decline significantly until AAA size exceeds 5.5 cm in women and 6.5 cm in men. Women are significantly less likely to meet device IFU criterion for EVAR. Aortic neck criteria and iliac access are important for men and women, but more women than men fail to meet IFU criterion. Devices that accommodate shorter infrarenal AAA neck length will have the greatest impact on expanding on-label EVAR regardless of gender. Lower profile devices and those that accommodate higher neck angulation are expected to expand EVAR eligibility further for women. EVAR eligibility is unlikely to be lost as AAAs enlarge to 5.5 cm in women and 6.5 cm in men. Observation of small AAAs until they reach the standard threshold size for repair should not compromise EVAR eligibility.

Predictors of Abdominal Aortic Aneurysm Sac Enlargement After Endovascular Repair

The majority of infrarenal abdominal aortic aneurysm (AAA) repairs in the United States are performed with endovascular methods. Baseline aortoiliac arterial anatomic characteristics are fundamental criteria for appropriate patient selection for endovascular aortic repair (EVAR) and key determinants of long-term success. We evaluated compliance with anatomic guidelines for EVAR and the relationship between baseline aortoiliac arterial anatomy and post-EVAR AAA sac enlargement. Patients with pre-EVAR and at least 1 post-EVAR computed tomography scan were identified from the M2S, Inc. imaging database (1999 to 2008). Preoperative baseline aortoiliac anatomic characteristics were reviewed for each patient. Data relating to the specific AAA endovascular device implanted were not available. Therefore, morphological measurements were compared with the most liberal and the most conservative published anatomic guidelines as stated in each manufacturer's instructions for use. The primary study outcome was post-EVAR AAA sac enlargement (>5-mm diameter increase). In 10 228 patients undergoing EVAR, 59% had a maximum AAA diameter below the 55-mm threshold at which intervention is recommended over surveillance. Only 42% of patients had anatomy that met the most conservative definition of device instructions for use; 69% met the most liberal definition of device instructions for use. The 5-year post-EVAR rate of AAA sac enlargement was 41%. Independent predictors of AAA sac enlargement included endoleak, age ≥ 80 years, aortic neck diameter ≥ 28 mm, aortic neck angle >60°, and common iliac artery diameter >20 mm. In this multicenter observational study, compliance with EVAR device guidelines was low and post-EVAR aneurysm sac enlargement was high, raising concern for long-term risk of aneurysm rupture.

Outcomes following endovascular abdominal aortic aneurysm repair (EVAR): An anatomic and device-specific analysis

We performed a device-specific comparison of long-term outcomes following endovascular abdominal aortic aneurysm repair (EVAR) to determine the effect(s) of device type on early and late clinical outcomes. In addition, the impact of performing EVAR both within and outside of specific instructions for use (IFU) for each device was examined. Between January 8, 1999 and December 31, 2005, 565 patients underwent EVAR utilizing one of three commercially available stent graft devices. Study outcomes included perioperative (< or =30 days) mortality, intraoperative technical complications and need for adjunctive procedures, aneurysm rupture, aneurysm-related mortality, conversion to open repair, reintervention, development and/or resolution of endoleak, device related adverse events (migration, thrombosis, or kinking), and a combined endpoint of any graft-related adverse event (GRAE). Study outcomes were correlated by aneurysm morphology that was within or outside of the recommended device IFU. chi2 and Kaplan Meier methods were used for analysis. Grafts implanted included 177 Cook Zenith (CZ, 31%), 111 Gore Excluder (GE, 20%), and 277 Medtronic AneuRx (MA, 49%); 39.3% of grafts were placed outside of at least one IFU parameter. Mean follow-up was 30 +/- 21 months and was shorter for CZ (20 months CZ vs 35 and 31 months for GE and MA, respectively; P < .001). Overall actuarial 5-year freedom from aneurysm-related death, reintervention, and GRAE was similar among devices. CZ had a lower number of graft migration events (0 CZ vs 1 GE and 9 MA); however, there was no difference between devices on actuarial analysis. Combined GRAE was lowest for CZ (29% CZ, 35% GE, and 43% MA; P = .01). Graft placement outside of IFU was associated with similar 5-year freedom from aneurysm-related death, migration, and reintervention (P > .05), but a lower freedom from GRAE (74% outside IFU vs 86% within IFU; P = .021), likely related to a higher incidence of graft thrombosis (2.3% outside IFU vs 0.3% within IFU; P = .026). The differences in outcome for grafts placed within vs outside IFU were not device-specific. EVAR performed with three commercially available devices provided similar clinically relevant outcomes at 5 years, although no graft migration occurred with a suprarenal fixation device. As anticipated, application outside of anatomically specific IFU variables had an incremental negative effect on late results, indicating that adherence to such IFU guidelines is appropriate clinical practice.

Retrograde type A dissection after endovascular stenting of the descending thoracic aorta. Is the risk real?☆

Retrograde type A dissection during or after endoluminal graft repair of the descending thoracic aorta is a potentially lethal complication unique to thoracic endografting. Our aim is to increase its awareness and to review possible etiological factors. Two hundred and eighty-seven patients with different thoracic aortic pathologies were treated with endovascular prostheses over the last 6 years (February 2000 to March 2006) under a single-site protocol. A retrospective review was conducted to identify any retrograde aortic dissections by both chart and film review. Factors that may have contributed to its formation were also documented. This population was analyzed for the complication of retrograde aortic dissection as well as the factors related to its occurrence. Seven patients (2.4%) with a gender distribution of three males and four females experienced a retrograde type A dissection within this sample at a median of 202 days. The mean age was 74 years (range 53-83). Aortic pathologies included aortic dissections (n=6) and thoracic aortic aneurysm (n=1). There were (n=3) 43% retrograde type A dissections identified within the perioperative period. Balloon angioplasty was performed in 71.4% (n=5). Two female patients (28.6%) had this event identified within their initial hospitalization with fatal consequences. Overall mortality was 57% (n=4) with extension of dissection the primary cause of death n=3 and open surgical repair (n=1) after an extension of retrograde dissection. Female gender, use of stent-grafts for dissection and possible aggressive balloon angioplasty may play a role in the cause of retrograde type A dissection. A close surveillance program is recommended when using thoracic endografts outside the recommended device instructions for use.