Use of a proactive duplex ultrasound protocol for hemodialysis access.

OBJECTIVE: Arteriovenous fistula (AVF) creation is the preferred approach for hemodialysis access; however, the maturation of AVFs is known to be poor. We established a proactive early duplex ultrasound (DUS) surveillance protocol for evaluating AVFs before attempted access. This study determined the effect of this protocol related to improving AVF maturation. METHODS: From 2008 to 2013, 153 patients received new upper extremity AVFs and an early DUS surveillance protocol at a single academic institution. The protocol involved an early DUS evaluation before hemodialysis cannulation of the AVF at 4 to 8 weeks after AVF creation. A positive DUS result was identified as a peak systolic velocity of >375 cm/s or a >50% stenosis on gray scale imaging, along with decreased velocity in the outflow vein. Patients with positive DUS findings underwent prophylactic endovascular or open intervention to assist with AVF maturation. Nature of secondary interventions, as well as AVF patency and maturation, were assessed. Overall clinical outcomes and fistula patency were investigated. RESULTS: During the study period, 183 upper extremity AVFs were created in 153 patients, including 82 radiocephalic, 63 brachiocephalic, and 38 brachiobasilic AVFs. A mortality rate of 43% (n = 66) was observed in a median follow-up period of 34.5 months (interquartile range, 19.6-46.9). A total of 164 early DUS were performed at a median of 6 weeks (interquartile range, 3.4-9.6 weeks) after the initial creation. Early DUS showed nine AVFs were occluded and were excluded from further analysis. Hemodynamically significant lesions were found in 62 AVFs (40%); however, only 17 (11%) were associated with an abnormal physical examination. Positive DUS finding prompted a secondary intervention in 81% of the patients. Among those with positive early DUS findings, AVF maturation was 70% in those undergoing a secondary intervention compared with 25% in those not undergoing a prophylactic intervention (P = .011). Primary-assisted patency for AVFs with early positive and negative DUS findings were 83% and 96% at 6 months, 64% and 89% at 1 year, and 52% and 82% at 2 years, respectively (P < .001). CONCLUSIONS: Early DUS surveillance of AVFs before initial access is reasonable to identify problematic AVFs that may not be reliably detected on clinical examination. Although DUS criteria for AVFs have yet to be universally accepted, proactive early postoperative DUS interrogation assists in the early detection of dysfunctional AVFs and improvement of fistula maturation. Despite improved patency in those with positive DUS findings who undergo prophylactic secondary intervention, overall patency remains inferior to those without an abnormality detected on early DUS imaging.

Reentry device aided endovascular aneurysm repair in patients with abdominal aortic aneurysm and unilateral iliac artery occlusion.

BACKGROUND: We report 2 cases of patients undergoing endovascular aneurysm repair (EVAR) using reentry devices to recanalize unilateral iliac artery occlusions and complete a bifurcated endovascular repair. METHODS: Patient 1 is a 70-year-old male with an enlarging 6.5-cm abdominal aortic aneurysm (AAA) and disabling left leg claudication with L external iliac occlusion with patent common and internal iliac arteries. Patient 2 is a 67-year-old male with an asymptomatic 4.0-cm AAA and L iliac chronic total occlusion (CTO) and disabling claudication. Both patients were poor operative candidates for open repair. RESULTS: Both patients underwent elective percutaneous EVAR along with left iliac artery revascularization. Initial angiography in both cases showed a blind ending of the left common iliac artery. Retrograde subintimal dissection through the occluded iliac segment was attempted but in both cases the wire was unable to traverse back into the true aortic lumen. Using either the Outback LTD or Pioneer reentry catheter, direct visualization of the true aortic lumen was obtained to re-enter the true lumen. The subintimal iliac tract was then predilated to facilitate routine EVAR in both cases. Both patients were discharged the following day and 1-year and 6-month follow-up imaging revealed aneurysm exclusion, no endoleak, and patent bilateral common iliac arteries with resolution of claudication symptoms and normal ankle-brachial indexes. The previously patent internal iliac artery was preserved. CONCLUSIONS: While not always technically possible, reentry device aided EVAR is safe, feasible, and durable in the mid-term and avoids the morbidity and mortality related to aortouniiliac/femoral-femoral bypass and open repair. This technique should be considered in patients with iliac artery CTO and concurrent AAA to allow total endovascular repair.

Comparison of fenestrated endografts and the snorkel/chimney technique.

OBJECTIVE: Recent approval by the Food and Drug Administration of custom fenestrated endografts has increased endovascular options for patients with short-neck or juxtarenal abdominal aortic aneurysms (AAAs). We sought to compare the early learning curve at a single institution of fenestrated repair vs the snorkel technique. METHODS: From 2009 to 2013, we performed 57 consecutive snorkel procedures for juxtarenal AAAs in an Institutional Review Board-approved prospective cohort, and since the summer of 2012, we gained access to the Food and Drug Administration-approved custom fenestrated device. Patient demographics, imaging, and operative techniques were compared between the first 15 cases for each of the snorkel (sn-EVAR) and fenestrated (f-EVAR) endovascular aneurysm repair (EVAR) techniques. RESULTS: Patient demographics and AAA morphology on preoperative imaging were similar between the groups. Operative time tended to be similar in the 3- to 4-hour range, with more fluoroscopy time and less contrast material used in f-EVAR than in sn-EVAR (P < .05) because of differing strategies of renal premarking. Larger delivery systems for f-EVAR required a higher rate of iliac conduits (40% vs 0%). Perioperative complications, short-term renal patency rates, and evidence of acute kidney injury were similar. CONCLUSIONS: The early experience of f-EVAR was similar to that of sn-EVAR in terms of patient demographics, case selection, and procedural characteristics. A significant portion of the learning curve for both procedures, particularly for f-EVAR, lies in the preoperative planning of fenestrations and the cannulation of branch vessels. Similar short-term postoperative outcomes between these two particular techniques indicate that both will have utility in the treatment of high-risk patients with complex anatomy.

Shuttering of the superior mesenteric artery during fenestrated endovascular aneurysm repair.

OBJECTIVE: Shuttering occurs when a scallop or fenestration does not align perfectly with the target vessel ostium and is potentially minimized by stenting. The current United States Food and Drug Administration-approved fenestrated endovascular aneurysm repair (f-EVAR) device is most commonly configured with an unstented superior mesenteric artery (SMA) scallop, thereby subjecting the SMA to risk of partial coverage. We aimed to describe the incidence, severity, and clinical effect of SMA shuttering during f-EVAR. METHODS: Patients undergoing f-EVAR using the commercially available Zenith (Cook Medical, Bloomington, Ind) fenestrated stent graft system containing an SMA scallop at our institution between September 2012 and January 2014 were included for analysis. Corrected multiplanar reformatted images on postoperative computed tomographic angiography were reviewed to measure SMA shuttering, defined as the percentage of scallop misalignment relative to the SMA ostial diameter. RESULTS: Of the 28 f-EVAR cases performed at our institution during the study period, 18 patients (78% male) had an SMA scallop and were included in this analysis. The median age was 78 years (interquartile range [IQR], 72-81 years), and the median abdominal aortic aneurysm size was 61 mm (IQR, 56-64 mm). Fifty-one vessels were targeted (18 SMA scallops, 32 renal fenestrations, 1 renal snorkel), with covered stents placed in all fenestrations. Target vessel catheterization and successful branch stent deployment was achieved in 100% of patients. SMA shuttering measured on postoperative computed tomographic angiography of any amount occurred in 50% of patients (range of SMA shuttering, 12%-40%). The severity of SMA shuttering varied: one patient had 11% to 20%, four had 21% to 30%, and four had 31 to 40%. When compared with patients without shuttering, patients with any SMA shuttering were noted to have a shorter infra-SMA neck length (17 vs. 25 mm; P = .007), higher volume of intraprocedural contrast administration (100 vs. 66 mL; P = .001), and had a trend toward longer procedural durations (240 vs. 188 minutes; P = .09). No association was found between SMA shuttering and the preoperative measured clock position of the visceral vessels, percentage of device oversizing, number of target vessels per patient, aortic diameter at the SMA or seal zone, aneurysm neck morphology, infrarenal neck length, scallop width, or SMA ostial diameter. No acute or chronic events of mesenteric ischemia were noted during a median clinical follow-up period of 11 months (IQR, 5-14 months). CONCLUSIONS: Even with the custom design of currently available fenestrated technology, shuttering of the SMA occurred in one-half of the patients in our cohort, although no clinical events were noted. Further details of the incidence, magnitude, and tolerance of SMA shuttering during f-EVAR are warranted to fully understand the clinical implication of this radiographic finding. Future design considerations for advanced EVAR should take into account SMA shuttering to further refine operative planning.

Elective EVAR in nonagenarians is safe in carefully selected patients.

BACKGROUND: Nonagenarians are typically considered poor operative candidates for major aortic intervention because of shorter life expectancy, multiple comorbidities, and increased perioperative morbidity and mortality. Endovascular abdominal aortic aneurysm repair (EVAR) has clearly been associated with a lower perioperative morbidity and mortality in most anatomically suitable patients. There have been many reports of the technical success of EVAR in octogenarians, but few documenting EVAR in nonagenarians. In this study, we sought to review our experience with elective EVAR in nonagenarians to determine outcomes, complications, and long-term survival after repair. METHODS: We retrospectively reviewed our prospectively maintained aneurysm database from 2000 to 2010 at an academic referral center. Fifteen patients ≥90 years old underwent elective EVAR. No symptomatic or ruptured abdominal aortic aneurysm patients >90 years old were treated. Comorbidities, preoperative and postoperative functional status, aneurysm size, and technical success rate were all recorded in accordance with Society for Vascular Surgery reporting guidelines. Follow-up was performed within 30 days, 6 months, and annually thereafter unless more frequent follow-up was indicated. RESULTS: Of the 749 EVAR procedures performed in the decade-long experience, 15 nonagenarians underwent repair (14 male, 93%; mean age, 90.3 ± 0.6 years). Mean aneurysm diameter was 6.4 ± 1.45 cm with a median diameter of 5.8 cm (range 4.5-8.8 cm). All patients were offered repair because of having good to excellent preoperative functional status with an average number of comorbidities per patient of 2.7. Immediate technical success rate was 100%. Median intensive care unit stay was 1 day (range 1-17 days). Mean length of stay was 4.6 ± 5.3 days with a median of 3.5 days. Thirty-day mortality was 0%. Mean follow-up was 35 months. Mean survival was 56 months. Overall survival estimated annually extending out to 5 years was 91.7%, 83.3%, 71.4%, 57.1%, and 38.1%, respectively. Thirty-day rate of any complication was 40%, with a 20% readmission rate, with many of the issues being related to wound complications. On follow-up imaging there were noted to be 4 (27%) type I, 9 (60%) type II, and no type III or type IV endoleaks identified. Overall reintervention rate was 27%. No ruptures were noted in the postoperative period or long-term follow-up, and there were no conversions to open surgery. CONCLUSIONS: We found a median survival of 56.2 months in this carefully selected cohort of EVAR in nonagenarians. As techniques and technology improve and evolve, and particularly as devices become lower profile, there is the potential to apply EVAR to the increasingly older population. If perioperative morbidity can be minimized and the patient has good functional status, EVAR can be a safe procedure and provide rupture-free survival.

Delayed hypogastric artery pseudoaneurysm following blunt trauma without evidence of pelvic fracture.

Arterial pelvic bleeding caused by bony fragments is a common finding in patients with pelvic fractures after blunt trauma (Durkin et al., Am J Surg 2006;192:211-23). However, arterial injury in the absence of bony fracture is extremely rare, and in the event that it does occur, is immediately discovered on cross-sectional imaging. We present an unusual case of a 15-year-old boy who was involved in a bicycle accident, and who, a week after his injury, developed a delayed hypogastric branch artery pseudoaneurysm causing sciatic nerve compression with a right foot drop. Initial magnetic resonance imaging scan and pelvic X-ray at the time of the injury showed no evidence of pelvic fracture or vascular damage. The pseudoaneurysm was successfully treated with selective coil embolization and hematoma evacuation. This study represents only the second reported case of delayed pelvic pseudoaneurysm in the absence of pelvic fracture.