A Review of the Evolution of Abdominal Aortic Endografts and Future Directions.

INTRODUCTION: Over the years, endovascular aortic aneurysm repair (EVAR) has become the gold-standard of therapy for abdominal aortic aneurysm (AAA) repairs. This study aims to analyze the evolution of stent graft devices and discuss the future direction of technological development. MATERIALS AND METHODS: In this paper, we will review prior eras of graft development (1992 to 2019) that included physician-made devices (era one), industry-made devices (era two), branch devices (era three), and fenestrated devices (era four). Additionally, future advancements that aim to overcome issues with short aneurysm necks, involvement of proximal visceral branches, and formation of endoleaks will be discussed. RESULTS: Future devices of note include a more conformable version of the EXCLUDER® device (W. L. Gore & Associates, Inc., Newark, Delaware) to better steer the top of the graft and modify for angulated necks, a version of the Endurant® device to include EndoAnchors (Medtronic plc, Minneapolis, Minnesota) to prevent formation of endoleaks, a novel Nellix® EVAS II device (Endologix Inc., Irvine, California) with aneurysm sac filling to prevent endoleaks and exclude the aneurysm sac, and an expanded Zenith® fenestrated device (Cook Medical Inc., Bloomington, Indiana) to include more visceral branches. This is in the setting of more recent advancements like pivoting fenestrated branch devices for "off-shelf" use and aneurysm repair that now extends to the thoracic aorta. CONCLUSION: With each iteration of devices, EVAR has evolved to overcome technical challenges and offer expanded applicability to different types of AAAs.

Dermabond and Tegaderm: A Better Surgical Incision Dressing.

Surgical site infections (SSIs) are a common source of morbidity with vascular surgery incisions, especially in the groin. Single institution case series have widely varying, but high incidences of groin wound infection after open lower extremity revascularization. Optimally, a dressing that did not require changes, had low cost, and was water resistant would be optimal in these patients. We developed and validate a new dressing utilizing Dermabond (Ethibond™) and Tegaderm™ for vascular surgery incisions that could simplify and reduce postoperative SSIs. In this initial experience, we reviewed 94 patients. Of the 94 patients, 0 had signs of infection superficial or deep, dehiscence, or evidence of nonhealing. Gluing a Tegaderm to an incision using Dermabond is a novel and easy way to perform dressing that reduces wound infection, increases patient comfort, avoids dressing changes, and allows visualization of the wound.

Defining the utility of anteroposterior venography in the diagnosis of venous iliofemoral obstruction.

BACKGROUND: Intravascular ultrasound (IVUS) is the current standard for the diagnosis of obstruction in the iliac and femoral veins. However, multiple venographic findings including collaterals, pancaking, and contrast thinning have been suggested to improve the sensitivity of venography. The objective of our study was to further elucidate where and how anteroposterior venography may successfully guide the diagnosis of venous obstruction. METHODS: A retrospective review of patients with chronic venous insufficiency who received iliofemoral stenting by a single practitioner at a tertiary medical center between January 2014 and August 2016 was performed. Patients who had records of anteroposterior venography and IVUS were included. Patients who underwent reoperation, did not have complete records of venography and IVUS, or had preoperative acute deep vein thrombosis were excluded. All patients with a greater than 50% luminal area reduction by IVUS underwent balloon angioplasty and stent placement. The locations of stenosis, collaterals, pancaking, and contrast thinning with venography, the locations of stenosis with IVUS, and the location of each stent placed were recorded. RESULTS: There were 107 patients who underwent venous stenting guided by venography and IVUS in this study. Six patients who underwent reoperation, 1 patient who had an acute preoperative deep vein thrombosis, and 14 patients who had incomplete records were excluded. Thus, 86 patients with 77 left lower extremity and 68 right lower extremity studies were available for analysis. The sensitivity by stenosis on venography was 4% in the left common iliac vein (CIV), 44% in the left external iliac vein (EIV), and 44% in the common femoral vein (CFV). The sensitivity by stenosis on venography in the right CIV, EIV, and CFV was 21%, 46%, and 40%, respectively. Combined, pancaking and collaterals had a sensitivity of 97% in the left CIV. IVUS resulted in a change in plan in 2%, 32%, and 48% of patients in the left CIV, EIV, and CFV, and in 26%, 35%, and 48% of patients in the right CIV, EIV, and CFV, respectively. CONCLUSIONS: Anteroposterior venography can indirectly diagnose obstruction of the left CIV through the identification of collaterals and pancaking. The combination of low sensitivity and a high rate of change of plan owing to IVUS precludes complete reliance on anteroposterior venography for the diagnosis of lesions in the left EIV and CFV and the right CIV, EIV, and CFV. IVUS must be used to comprehensively identify all venous iliofemoral lesions.

Defining Types and Determining Risk Factors for Vascular Surgery Readmissions.

BACKGROUND: Vascular surgery patients typically have numerous comorbidities, which puts them at higher risk for postoperative readmissions. This study aims to investigate the risk factors for and appropriately categorize the various types of vascular surgery readmissions. METHODS: Nine hundred seventy-two patients were retrospectively reviewed. Readmissions were classified into 3 separate groups: readmissions that occurred between 0 and 30 days (30-day readmissions), 31-90 days (3-month readmissions), and 91-365 days (1-year readmissions). Each readmission was then assigned to 1 of the 4 categories based on whether they were related to the index procedure and whether they were planned. Univariate tests were performed for demographic variables based on their type of readmission, and logistic regressions were then performed to identify predictors of each unplanned, related readmissions. RESULTS: The overall 30-day readmission rate was 21.9% (n = 213). The unplanned, related readmission cohort (n = 83) had the highest readmission rate of 8.5%. The related, planned readmission rate was 5.9% (n = 58), while the unrelated, unplanned readmission rate was 5.6% (n = 55). In contrast, the overall 1-year readmission rate was 40.0% (n = 389), with the largest category being unplanned, unrelated readmissions at 19.7% (n = 191). The unplanned, related readmission rate was 8.7% (n = 85), whereas the planned, related readmission rate was 5.7% (n = 55). Compared with other types of readmissions, unplanned, related readmissions tended to affect patients who were younger, had poor glycemic control, and had higher body mass indexes (BMIs). Multivariate predictors of unplanned, related readmissions were poor glycemic control at 3 months (odds ratio [OR]: 2.16, P = 0.03), and BMI at 30 days (OR: 1.06, P = 0.04) and 1 year (OR: 1.05, P = 0.04). CONCLUSIONS: Readmissions have varying risk factors depending on their category; targeting glycemic control and obesity may reduce unplanned, related readmissions.

Bilateral May-Thurner syndrome refractory to iliac aneurysm repair.

Venous complications of iliac artery aneurysms are rare. We report the case of bilateral iliac aneurysms that resulted in iliac vein outflow obstruction despite endovascular aneurysm repair. In our patient, bilateral iliac vein stenting resulted in symptom resolution.

Use of the distal radial artery remnant for autogenous radial-cephalic wrist fistula after radial artery harvest for coronary artery bypass grafting.

Harvesting of the radial artery is a common technique used to provide conduit for coronary artery bypass graft surgery. We report the case of a patient with exhausted left upper extremity access options, history of left upper extremity dialysis access-associated steal syndrome, and prior right radial artery harvest for coronary artery bypass graft who received an autogenous distal radial artery remnant to cephalic vein wrist fistula.

Delayed Tibioperoneal Trunk Aneurysm after Atherectomy and Balloon Angioplasty.

True infrapopliteal aneurysms occur very rarely; the majority of reported cases are secondary to trauma or infection. We report the development of a tibioperoneal trunk aneurysm 6 months after atherectomy and angioplasty and describe subsequent open surgical repair via a great saphenous vein bypass graft.

Evolution of type II endoleaks based on different ultrasound-identified patterns.

OBJECTIVE: The objective of this study was to delineate the specific types of waveforms that exist in type II endoleaks (T2ELs) and their effect on aneurysm sac size. METHODS: Patients who underwent an endovascular aneurysm repair and were diagnosed with a T2EL were included in the study. The flow velocity characteristics of the T2ELs were evaluated in detail with duplex ultrasound. Four different flow patterns were identified: high resistance, low flow; low resistance, low flow; low resistance, high flow; and to-fro flow. The type and number of vessels involved, time at detection, evolution, and need for treatment were recorded. The aneurysm sac diameter was monitored with duplex ultrasound. A computed tomography scan was always performed at baseline within 1 month of the procedure and repeated only when symptoms developed or there were changes in the ultrasound examination findings, such as sac enlargement. RESULTS: Of 382 patients who underwent endovascular aneurysm repair in our institution, 56 (14.65%) were found to have a T2EL. There were 52 male and four female patients with a mean age of 74 years (61-86 years). The T2EL was diagnosed within the first month in 32 patients; 9 patients were diagnosed at 3 months, 5 patients at 6 months, 3 patients at 9 months, and 7 patients at 1 year or later. There were 43 patients who had a T2EL involving one vessel; two vessels were involved in 11 patients and three vessels were involved in two patients. During follow-up, several changes were observed for the different types of T2EL. High-resistance, low-flow endoleak was detected in 14 patients; of those, 13 were occluded and 1 converted to high flow. Low-resistance, low-flow endoleak was detected in seven patients; of those, 5 were occluded, 1 remained stable, and 1 converted to high flow with sac enlargement requiring treatment. Low-resistance, high-flow endoleak was found in 13 patients; of those, 8 were occluded, 3 remained stable, and 2 had sac enlargement requiring treatment; 1 patient presented with rupture. Finally, to-fro flow was identified in the majority of the patients (22); of those, 14 occluded, 3 remained stable, and 5 had sac enlargement requiring treatment; 2 patients presented with rupture. No deaths due to T2EL were encountered. CONCLUSIONS: Most of the T2ELs resulted in spontaneous occlusion and were not associated with sac enlargement. A low-resistance, high-flow or to-fro flow T2EL has higher chances of sac enlargement, rupture, and requiring reintervention.

Values Affirmation Intervention Reduces Achievement Gap between Underrepresented Minority and White Students in Introductory Biology Classes.

Achievement gaps between underrepresented minority (URM) students and their white peers in college science, technology, engineering, and mathematics classrooms are persistent across many white-majority institutions of higher education. Attempts to reduce this phenomenon of underperformance through increasing classroom structure via active learning have been partially successful. In this study, we address the hypothesis that the achievement gap between white and URM students in an undergraduate biology course has a psychological and emotional component arising from stereotype threat. Specifically, we introduced a values affirmation exercise that counters stereotype threat by reinforcing a student's feelings of integrity and self-worth in three iterations of an intensive active-learning college biology course. On average, this exercise reduced the achievement gap between URM and white students who entered the course with the same incoming grade point average. This result suggests that achievement gaps resulting from the underperformance of URM students could be mitigated by providing students with a learning environment that removes psychological and emotional impediments of performance through short psychosocial interventions.

Downregulation of dendritic HCN channel gating in epilepsy is mediated by altered phosphorylation signaling.

The onset of spontaneous seizures in the pilocarpine model of epilepsy causes a hyperpolarized shift in the voltage-dependent activation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channel-mediated current (Ih) in CA1 hippocampal pyramidal neuron dendrites, contributing to neuronal hyperexcitability and possibly to epileptogenesis. However, the specific mechanisms by which spontaneous seizures cause downregulation of HCN channel gating are yet unknown. We asked whether the seizure-dependent downregulation of HCN channel gating was due to altered phosphorylation signaling mediated by the phosphatase calcineurin (CaN) or the kinase p38 mitogen-activated protein kinase (p38 MAPK). We first found that CaN inhibition upregulated HCN channel gating and reduced neuronal excitability under normal conditions, showing that CaN is a strong modulator of HCN channels. We then found that an in vitro model of seizures (1 h in 0 Mg2+ and 50 microM bicuculline at 35-37 degrees C) reproduced the HCN channel gating change seen in vivo. Pharmacological inhibition of CaN or activation of p38 MAPK partially reversed the in vitro seizure-induced hyperpolarized shift in HCN channel gating, and the shift was fully reversed by the combination of CaN inhibition and p38 MAPK activation. We then demonstrated enhanced CaN activity as well as reduced p38 MAPK activity in vivo in the CA1 hippocampal area of chronically epileptic animals. Pharmacological reversal of these phosphorylation changes restored HCN channel gating downregulation and neuronal hyperexcitability in epileptic tissue to control levels. Together, these results suggest that alteration of two different phosphorylation pathways in epilepsy contributes to the downregulation of HCN channel gating, which consequently produces neuronal hyperexcitability and thus may be a target for novel antiepileptic therapies.

Adjunctive renal artery revascularization during juxtarenal and suprarenal abdominal aortic aneurysm repairs.

BACKGROUND: We report a 15-year experience with renal artery revascularization during abdominal aortic aneurysm (AAA) repair. METHODS: AAA repairs from 1994 to 2009 were reviewed. Postoperative complications, renal function, patency, and survival in patients undergoing renal artery revascularization were evaluated and compared with a control group of patients undergoing juxtarenal AAA repairs not requiring renal artery revascularization. RESULTS: Sixty patients underwent renal artery revascularization during AAA repair. Transient postoperative renal insufficiency occurred in 20 patients. Temporary hemodialysis was required in 3 patients, with none requiring permanent hemodialysis. There was 1 postoperative death. There was 1 renal artery revascularization failure at 1 month but no other graft failures at 12 months median follow-up evaluation (1-year patency, 97%). In comparison with the control group, transient renal insufficiency and pulmonary complications (33.3% vs 19.8%; P = .042) were more common with renal artery revascularization, with no differences in long-term renal complications or mortality. CONCLUSIONS: Renal artery revascularization can be performed during AAA repair with excellent patency and minimal morbidity.

Open abdominal aortic aneurysm repair in the endovascular era: effect of clamp site on outcomes.

OBJECTIVE: To describe a contemporary series of open abdominal aortic aneurysm (AAA) repairs in patients not anatomically suitable for endovascular AAA repair. METHODS: A prospectively maintained database including consecutive nonruptured open aneurysm repairs from March 1, 2000, through July 31, 2007, was reviewed. Patient demographic characteristics and perioperative outcomes were evaluated and stratified based on proximal aortic cross-clamp placement. RESULTS: A total of 185 patients with AAA underwent 103 infrarenal and 82 suprarenal cross-clamp repairs. Overall, the complication rate was 37.0% with infrarenal and 61.0% with suprarenal cross-clamps (P = .001). The 30-day mortality was 2.9% with infrarenal and 6.1% with suprarenal cross-clamps (P = .18). Postoperative renal insufficiency (29.3% vs 7.8%; P < .001) and pulmonary complications (25.6% vs 12.6%; P = .03) were more frequent with suprarenal cross-clamps. Suprarenal cross-clamps were associated with greater intraoperative blood loss (2586 mL vs 1638 mL; P = .006), operative duration (391 min vs 355 min; P = .005), use of adjunctive renal and/or visceral grafts (43.9% vs 1.9%; P < .001), duration of intensive care unit stay (4.5 days vs 3.0 days; P = .006), and hospital length of stay (9 days vs 7 days; P = .04). Of patients who received a suprarenal cross-clamp, 25.6% required temporary nursing home placement vs 17.5% with an infrarenal cross-clamp (P = .14). CONCLUSIONS: Until fenestrated and branched endografts are available, open AAA repairs will become increasingly complex. Suprarenal cross-clamping is associated with increased rates of complications but similar mortality rates and need for nursing home placement. With the disappearance of straightforward open aneurysm repair, trainees in vascular surgery will have to learn AAA repair almost exclusively by operating on patients with complex AAAs. Fewer surgeons will perform these repairs, and fewer fellows will be able to complete the operation independently immediately after training.