Endoscopic findings do not predict per-oral pyloromyotomy (POP) response.

INTRODUCTION: Gastroparesis is a life-altering diagnosis caused by the stomach's inability to function in the absence of a mechanical obstruction. The primary causes are idiopathic, diabetic, and postoperative. Our first-line treatment for medical refractory gastroparesis is the endoscopic per-oral pyloromyotomy (POP) procedure. Predicting clinical response cost effectively remains elusive. METHODS: All patients who underwent a POP procedure at our institution by a single surgical endoscopist from January 1, 2019 to June 30, 2020 were retrospectively reviewed. All endoscopic data were prospectively collected. The patients were followed by a survey including the Gastroparesis Cardinal Symptom Index (GCSI) and other relevant postoperative measures. The primary endpoint was clinical response defined as ≥ 1.0 decrease in the GCSI from preoperative to the time of survey. Secondary outcome was normalization of the gastric emptying study (GES). RESULTS: Our patient population is 85% female and has an average age of 44.8 years. The diagnosis of gastroparesis is 71% iatrogenic, 19% postoperative, and 10% diabetic. On endoscopy, 30% had bile in the stomach and 65% had any degree of pylorospasm. The primary outcome measure of clinical response was 39% at an average of 697 ± 151 days post-POP, but 66% of patients attested to an improvement in their symptoms. Of 68 postoperative gastric emptying studies 50% normalized at an average of 145 ± 98 days. Following univariate and multivariate analyses of preoperative data and endoscopic findings, there were no significant predictors of clinical response. A preoperative GCSI ≥ 2.6 trends toward significance (OR 6.87, p = 0.058). CONCLUSION: Endoscopic findings at the time of POP do not correlate with clinical response. The GCSI model currently used to measure clinical response may not accurately capture the full clinical picture. The long-term durability of endoscopic myotomy to treat medical refractory gastroparesis needs to be studied further to improve patient selection.

Primary single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) versus sleeve gastrectomy to SADI conversions: a comparison study of prevalence and safety.

BACKGROUND: Conversion from sleeve gastrectomy (SG) to single anastomosis duodeno-ileal bypass (SADI) is becoming increasingly common, but data regarding safety is of these conversions is scarce. As such, the objective of this study was to compare the 30-day rate of serious complications and mortality of primary SADI (p-SADI-S) with SG to SADI (SG-SADI) conversions. METHODS: This retrospective cohort study analyzed the MBSAQIP database. Patients undergoing p-SADI-S and SG-SADI were included. Data collection was limited to 2020 and 2021. A multivariable logistic regression analysis was performed between groups to determine if SG-SADI was an independent predictor of 30-day serious complications or mortality. RESULTS: A total of 783 patients were included in this study, 488 (62.3%) underwent p-SADI-S and 295 (37.6%) underwent SG-SADI. The mean body mass index (BMI) at the time of surgery was lower in the SG-SADI cohort (45.1 vs 51.4 kg/m2, p < 0.001). Indications for revision in the SG-SADI cohort included weight recurrence (50.8%), inadequate weight loss (41.0%), other (3.0%), GERD (2.7%), and persistent comorbidities (2.5%). SG-SADI had longer operative times (156.7 vs 142.1 min, p < 0.001) and was not associated with a higher rate of serious complications (5.7 vs 6.9%, p = 0.508) compared to p-SADI-S. p-SADI-S was associated with a higher rate of pneumonia (1.2 vs 0.0%, p < 0.001), and SG-SADI was not correlated with higher rates of reoperation (3.0 vs 3.2%, p = 0.861), readmission (5.4 vs 5.5%, p = 0.948) and death (0.0 vs 0.2%, p = 0.437). On multivariable analysis, SG-SADI was not independently predictive of serious complications (OR 0.81, 95% CI 0.43 to 1.52, p = 0.514) when adjusting for age, sex, BMI, comorbidities, and operative time. CONCLUSIONS: The prevalence of SG-SADI is high, representing 37.6% of SADI-S procedures. Conversion from sleeve to SADI, is safe, and as opposed to other studies of revisional bariatric surgery, has similar 30-day complication rates to primary SADI-S.

Real-time intraoperative functioning lumen imaging probe during endoscopic per-oral pyloromyotomy (pop).

BACKGROUND: Endoscopic per-oral pyloromyotomy (POP) has emerged as a safe and effective first line option in medically refractory gastroparesis. Determining the appropriate extent of the pyloromyotomy continues to present a challenge as there are no standardized tools for measuring changes in pyloric distensibility during the procedure. The objective of this study was to evaluate the utility of using impedance planimetry with endoscopic functional luminal imaging probe (FLIP) to measure changes in pyloric distensibility after POP, and to compare these changes with improvement in symptoms and objective gastric emptying. METHODS: Patients with medically refractory gastroparesis underwent POP with FLIP measurements of the pylorus (EndoFLIP®, Medtronic, Fridley MN). FLIP measurements, as well as changes in symptoms measured by the validated gastroparesis cardinal symptom index (GCSI) and scintigraphic gastric emptying studies (GES), were evaluated before and after POP. RESULTS: A total of 14 patients underwent measurement with FLIP during POP, 12 of whom had pre- and post-POP measurements. Mean pyloric diameter increased by 1.4 mm, from 13.9 mm to 15.3 mm (p = 0.0012). Mean distensibility index increased from 6.2 mm2/mmHg to 9.1 mm2/mmHg (p = 0.0074). Successful division of the pylorus was achieved in 100% of patients with a mean operative time of 36 min and no perioperative complications. The mean length of stay was 0.7 days (0-3 days). Post-POP mean GCSI score improved from 2.97 to 2.28 at a mean follow-up time of 27 days (p < 0.001). Objective improvement in gastric emptying was observed in 80% of patients with scintigraphic GES, with mean four-hour retention decreasing from 46.3% to 32.4% (p < 0.007). CONCLUSIONS: FLIP is a safe and feasible tool to provide objective measurements during POP. Larger cohorts with longer follow-up are required to determine if measured improvements in pyloric diameter and distensibility are predictive of sustained improvements in GCSI and GES.

Gastroparesis with concomitant gastrointestinal dysmotility is not a contraindication for per-oral pyloromyotomy (POP).

INTRODUCTION: Per-oral pyloromyotomy (POP or G-POEM) provides significant short-term improvements in symptoms and objective emptying for patients with medically refractory gastroparesis, but it is unclear if patients with gastroparesis and co-existing dysmotility (small bowel or colonic delay) also benefit. In this study, we used wireless motility capsule (WMC) data to measure outcomes in patients with isolated gastroparesis (GP) and gastroparesis with co-existing dysmotility (GP + Dys) who underwent POP. METHODS: We retrospectively analyzed patients who had POP and completed WMC data during their evaluation of intestinal dysmotility. WMC data were reviewed to identify patients who demonstrated isolated GP or GP + Dys. Each patient's pre-op and post-op Gastroparesis Cardinal Symptom Index (GCSI) and 4-h solid-phase scintigraphy gastric emptying studies (GES) scores were compared to evaluate improvement. RESULTS: Of the entire cohort (n = 73), 89% were female with a mean age of 47.0 ± 15.0 years old. Gastroparesis etiologies were divided among idiopathic (54.8%), diabetic (26%), postsurgical (8.2%), autoimmune (5.5%), and multifactorial (5.5%). Forty-one patients (56%) had GP and 32 patients (44%) had GP + Dys. GCSI improved after POP whether the patient had isolated GP (- 12.31, p < 0.001) or GP + Dys (- 9.58, p < 0.001); however, there was no significant difference in total GCSI improvement between the two groups. A subset of patients had postoperative GES available (n = 47). In the isolated GP and GP + Dys cohorts, 15/28 (54%) and 12/19 (63%) patients had normal post-op 4-h GES, respectively, but no statistical difference between the two groups. CONCLUSION: Patients with medically refractory gastroparesis with and without concomitant gastrointestinal dysmotility show short-term subjective and objective improvement after POP. Concomitant small bowel or colonic dysmotility should not deter physicians from offering POP in carefully selected patients with gastroparesis.

Per-oral Pyloromyotomy (POP) for Medically Refractory Gastroparesis: Short Term Results From the First 100 Patients at a High Volume Center.

OBJECTIVE: For patients with gastroparesis, temporary pyloric disruption has been shown to improve symptoms and gastric emptying. Per-oral pyloromyotomy (POP) is an innovative endoscopic procedure to divide the pylorus from within a submucosal tunnel, as a corollary to surgical pyloromyotomy. Here we evaluate subjective and objective outcomes 12-weeks after POP at a high volume center. METHODS: The first 100 consecutive patients undergoing POP were included, with procedure dates between January 2016 and October 2017. Patients were evaluated using the Gastroparesis Cardinal Symptom Index (GCSI), and 4-hour solid-phase scintigraphic gastric emptying studies (GES) prior to procedure and at 90 days post-POP RESULTS:: The study cohort was 85% female with a mean age of 45.0 ±â€Š14.6 years. Gastroparesis etiologies were divided among idiopathic (56%), diabetic (21%), postsurgical (19%), and other in 4%. There were 67% of the patients who had previous endoscopic or surgical interventions for gastroparesis. Most POP procedures were performed in the operating room (97%) and were completed in an average of 33 minutes. Ten patients incurred complications (10%), which included 1 diagnostic laparoscopy and 2 cases of gastrointestinal bleeding. Overall GCSI improved from a preoperative mean of 3.82 ±â€Š0.86 to 2.54 ±â€Š1.2 (P < 0.001). The improvement in each GCSI subscore was also highly statistically significant. Among the patients with postoperative GES available, 78% had objectively better 4-hour emptying with a mean improvement in retention by 23.6% (P < 0.001). This included 57% of patients with normal gastric emptying post-POP. CONCLUSION: For patients with medically refractory gastroparesis, POP results in both subjective and objective improvement in the majority of patients. Prior intervention does not obviate POP as a therapeutic option. POP should be included along the treatment algorithm for patients with gastroparesis as an organ-sparing procedure.

Magnetic surgery: first U.S. experience with a novel device.

INTRODUCTION: Magnet-assisted surgery is a new platform within minimally invasive surgery. The Levita™ Magnetic Surgical System, the first magnetic surgical system to receive Food and Drug Administration (FDA) approval, includes a deployable, magnetic grasper and an external magnet that is used to manipulate the grasper within the peritoneal cavity. This system is currently approved for patients undergoing laparoscopic cholecystectomy with a body mass index (BMI) between 21 and 34 kg/m2. Herein, we detail the first United States experience with the Levita™ Magnetic Surgical System during laparoscopic cholecystectomy. METHODS: The Levita™ Magnetic Surgical System was used on consecutive patients undergoing laparoscopic cholecystectomy at our institution from June 2016 through November 2016. Only patients undergoing elective surgery and those with a body mass index (BMI) between 21 and 34 kg/m2 were included. Baseline patient characteristics, operative time, and perioperative details were collected. RESULTS: A total of ten patients underwent laparoscopic cholecystectomy with the Levita™ Magnetic Surgical System during the defined study period. The mean age at the time of surgery was 49.0 years and the average BMI of the cohort was 27.6 kg/m2. The average operative time was 64.4 min. There were no perioperative complications. Seven (70.0%) patients were discharged to home on the day of surgery, while the remaining three (30.0%) patients were discharged to home on postoperative day number one. Surgeons reported that the magnetic grasper was easy to use and provided adequate tissue retraction and exposure. CONCLUSIONS: The Levita™ Magnetic Surgical System is safe and feasible to use in patients undergoing laparoscopic cholecystectomy. Routine use of this system may facilitate a reduction in the total number of laparoscopic trocars used, leading to less tissue trauma and improved cosmesis. Additional studies are needed to determine the applicability and utility of this system for other general surgery cases.

The LargPAD Trial: Phase IIA evaluation of l-arginine infusion in patients with peripheral arterial disease.

OBJECTIVE: Endothelial function is improved by l-arginine (l-arg) supplementation in preclinical and clinical studies of mildly diseased vasculature; however, endothelial function and responsiveness to l-arg in severely diseased arteries is not known. Our objective was to evaluate the acute effects of catheter-directed l-arg delivery in patients with chronic lower extremity ischemia secondary to peripheral arterial disease. METHODS: The study enrolled 22 patients (45% male) with peripheral arterial disease (mean age, 62 years) requiring lower extremity angiography. Endothelium-dependent relaxation of patent but atherosclerotic superficial femoral arteries was measured using a combination of intravascular ultrasound (IVUS) imaging and a Doppler FloWire (Volcano Corporation, Rancho Cordova, Calif) during the infusion of incremental acetylcholine (10-6 to 10-4 molar concentration) doses. Patients received 50 mg (n = 3), 100 mg (n = 10), or 500 mg (n = 9) l-arg intra-arterially, followed by repeat endothelium-dependent relaxation measurement (limb volumetric flow). IVUS-derived virtual histology of the culprit vessel was also obtained. Endothelium-independent relaxation was measured using a nitroglycerin infusion. Levels of nitrogen oxides and arginine metabolites were measured by chemiluminescence and mass spectrometry, respectively. RESULTS: Patients tolerated limb l-arg infusion well. Serum arginine and ornithine levels increased by 43.6% ± 13.0% and 23.2% ± 10.3%, respectively (P < .005), and serum nitrogen oxides increased by 85% (P < .0001) after l-arg infusion. Average vessel area increased by 6.8% ± 1.3% with l-arg infusion (acetylcholine 10-4; P < .0001). Limb volumetric flow increased in all patients and was greater with l-arg supplementation by 130.9 ± 17.6, 136.9 ± 18.6, and 172.1 ± 24.8 mL/min, respectively, for each cohort. Maximal effects were seen with l-arg at 100 mg (32.8%). Arterial smooth muscle responsiveness to nitroglycerin was intact in all vessels (endothelium-independent relaxation, 137% ± 28% volume flow increase). IVUS-derived virtual histology indicated plaque volume was 14 ± 1.3 mm3/cm, and plaque stratification revealed a predominantly fibrous morphology (46.4%; necrotic core, 28.4%; calcium, 17.4%; fibrolipid, 6.6%). Plaque morphology did not correlate with l-arg responsiveness. CONCLUSIONS: Despite extensive atherosclerosis, endothelial function in diseased lower extremity human arteries can be enhanced by l-arg infusion secondary to increased nitric oxide bioactivity. Further studies of l-arg as a therapeutic modality in patients with endothelial dysfunction (ie, acute limb ischemia) are warranted.

Per oral endoscopic pyloromyotomy for refractory gastroparesis: initial results from a single institution.

INTRODUCTION: Gastroparesis is a debilitating disease characterized by delayed gastric emptying in the absence of mechanical obstruction. A new intramural technique, per oral endoscopic pyloromyotomy (POP), has been proposed as an alternative to surgical pyloroplasty for the management of medical refractory gastroparesis. Herein, we detail the short-term results of POP at our institution. METHODS: POP was first performed at our institution in January 2016. All patients undergoing POP for management of gastroparesis from January 2016 through January 2017 were prospectively followed. All patients underwent a 4-h, non-extrapolated gastric emptying scintigraphy study and were asked to rate their symptoms using the Gastroparesis Cardinal Symptom Index (GCSI) at their pre-procedure visit and at 3 months post-procedure. RESULTS: A total of 47 patients underwent POP during the defined study period. Twenty-seven (57.4%) patients had idiopathic gastroparesis, 12 (25.6%) had diabetic gastroparesis, and eight (17.0%) had post-surgical gastroparesis. Forty-one (87.2%) patients had at least one previous intervention (i.e., enteral feeding tube, gastric pacer, botox injection) for their gastroparesis symptoms. All patients had evidence of gastroparesis on pre-procedure gastric emptying studies. The average length of hospital stay was 1 day. One patient died within 30-days of their index procedure which was unrelated to the procedure itself. The average pre-procedure percentage of retained food at 4 h was 37% compared to an average post-procedure percentage of 20% (p < 0.03). The average pre-procedure GCSI score was 4.6 compared to an average post-procedure GCSI of 3.3 (p < 0.001). CONCLUSIONS: POP is a safe and feasible endoscopic intervention for medical refractory gastroparesis. Additional follow-up is required to determine the long-term success of this approach in alleviating gastroparesis symptoms.

In vivo evaluation of biomimetic fluorosurfactant polymer-coated expanded polytetrafluoroethylene vascular grafts in a porcine carotid artery bypass model.

OBJECTIVE: The objective of this study was to evaluate the potential for biomimetic self-assembling fluorosurfactant polymer (FSP) coatings incorporating heptamaltose (M7-FSP) to block nonspecific protein adsorption, the cell adhesive RGD peptide (RGD-FSP), or the endothelial cell-selective CRRETAWAC peptide (cRRE-FSP) to improve patency and endothelialization in small-diameter expanded polytetrafluoroethylene (ePTFE) vascular graft implants. METHODS: ePTFE vascular grafts (4 mm in diameter, 5 cm in length) were coated with M7-FSP, RGD-FSP, or cRRE-FSP by dissolving FSPs in distilled water and flowing solution through the graft lumen for 24 hours. Coatings were confirmed by receding water contact angle measurements on the lumen surface. RGD-FSP and cRRE-FSP grafts were presodded in vitro with porcine pulmonary artery endothelial cells (PPAECs) using a custom-designed flow system. PPAEC coverage on the lumen surface was visualized with epifluorescent microscopy and quantified. Grafts were implanted as carotid artery interposition bypass grafts in seven pigs for 33 ± 2 days (ePTFE, n = 3; M7-FSP, n = 4; RGD-FSP, n = 3; cRRE-FSP, n = 4). Patency was confirmed immediately after implantation with duplex color flow ultrasound and at explantation with contrast-enhanced angiography. Grafts were sectioned for histology and stained: Movat pentachrome stain to outline vascular layers, immunofluorescent staining to identify endothelial cells (anti-von Willebrand factor antibody), and immunohistochemical staining to identify smooth muscle cells (anti-smooth muscle α-actin antibody). Neointima to lumen area ratio was determined to evaluate neointimal hyperplasia. RESULTS: Receding water contact angle measurements on graft luminal surfaces were significantly lower (P < .05) on FSP-coated ePTFE surfaces (M7-FSP, 40 ± 16 degrees; RGD-FSP, 25 ± 10 degrees; cRRE-FSP, 33 ± 16 degrees) compared with uncoated ePTFE (126 ± 2 degrees), confirming presence of the FSP layer. In vitro sodding of PPAECs on RGD-FSP and cRRE-FSP grafts resulted in a confluent monolayer of PPAECs on the luminal surface, with a similar cell population on RGD-FSP (1200 ± 187 cells/mm(2)) and cRRE-FSP (1134 ± 153 cells/mm(2)) grafts. All grafts were patent immediately after implantation, and one of three uncoated, two of three RGD-FSP, two of four M7-FSP, and two of four cRRE-FSP grafts remained patent after 1 month. PPAEC coverage of the lumen surface was seen in all patent grafts. RGD-FSP grafts had a slightly higher neointima to lumen area ratio (0.53 ± 0.06) compared with uncoated (0.29 ± 0.15), M7-FSP (0.20 ± 0.15), or cRRE-FSP (0.17 ± 0.09) grafts. CONCLUSIONS: Biomimetic FSP-coated ePTFE grafts can be used successfully in vivo and have potential to support endothelialization. Grafts modified with the M7-FSP and cRRE-FSP showed lower intimal hyperplasia compared with RGD-FSP grafts.

Dextran or Saline Can Replace Contrast for Intravascular Optical Coherence Tomography in Lower Extremity Arteries.

PURPOSE: To examine the hypothesis that alternative flush media could be used for lower extremity optical coherence tomography (OCT) imaging in long lesions that would normally require excessive use of contrast. METHODS: The OPTical Imaging Measurement of Intravascular Solution Efficacy (OPTIMISE) trial was a single-center, prospective study (ClinicalTrials.gov identifier NCT01743872) that enrolled 23 patients (mean age 68±11 years; 14 men) undergoing endovascular intervention involving the superficial femoral artery. Four flush media (heparinized saline, dextran, carbon dioxide, and contrast) were used in succession in random order for each image pullback. Quality was defined as ≥270° visualization of vessel wall layers from each axial image. Mean proportions (± standard deviation) of image quality for each flush medium were assessed using 1-way analysis of variance and are reported with the 95% confidence intervals (CI). RESULTS: Four OCT catheters failed, leaving 19 patients who completed the OCT imaging protocol; from this cohort, 51 highest quality runs were selected for analysis. Average vessel diameter was 3.99±1.01 mm. OCT imaging allowed 10- to 15-µm resolution of the lumen border, with diminishing quality as vessel diameter increased. Plaque characterization revealed fibrotic lesions. Mean proportions of image quality were dextran 87.2%±12% (95% CI 0.81 to 0.94), heparinized saline 74.3%±24.8% (95% CI 0.66 to 0.93), contrast 70.1%±30.5% (95% CI 0.52 to 0.88), and carbon dioxide 10.0%±10.4% (95% CI 0.00 to 0.26). Dextran, saline, and contrast provided better quality than carbon dioxide (p<0.001). CONCLUSION: OCT is feasible in peripheral vessels <5 mm in diameter. Dextran or saline flush media can allow lesion characterization, avoiding iodinated contrast. Carbon dioxide is inadequate for peripheral OCT imaging. Axial imaging may aid in enhancing durability of peripheral endovascular interventions.

Upper Extremity Steal Syndrome Is Associated with Atherosclerotic Burden and Access Configuration.

BACKGROUND: Clinically significant steal syndrome occurs in a subset of dialysis patients with arteriovenous (AV) access. Factors associated with steal are poorly understood. Severe symptoms require access revision or sacrifice, potentially jeopardizing access options. Our objective was to review our dialysis access experience to identify factors associated with significant steal syndrome. METHODS: We reviewed all adult patients undergoing their first permanent upper extremity access, AV fistula (AVF) or AV graft (AVG), between January 2008 and July 2011 at a single center. Medical, demographic, and access characteristics were collected from our electronic medical record and a local dialysis center's database. Patients who required correction of steal syndrome were compared with the larger access cohort. Statistical analysis included Fisher's exact test and χ(2) for noncontinuous variables and unpaired t-test for continuous variables. RESULTS: Of the 303 patients, 15 required correction for steal syndrome (8 of 232 AVF and 7 of 71 AVG). Eight were ligated; 2 were initially banded, then ligated; and 5 underwent distal revascularization with interval ligation. Coronary artery disease was more prevalent in steal syndrome patients (66.7% vs. 25%, P = 0.001); the same was found with peripheral arterial disease (40% vs. 13.8%, P = 0.02). Furthermore, more patients with steal syndrome were on clopidogrel for cardiovascular reasons (40% vs. 9%, P = 0.002). Steal syndrome only developed with AVF and AVG using brachial artery inflow. No cases of steal syndrome arose from radial/ulnar inflow (P = 0.03). All AVG with steal syndrome had a straight configuration; no looped AVG developed steal (P = 0.02). Other patient characteristics such as age, sex, race, hypertension, diabetes mellitus, congestive heart failure, cerebrovascular accident, cause of end-stage renal disease, and other medication history were not different between groups. CONCLUSIONS: Clinically significant steal syndrome is associated with disease in coronary and peripheral arterial beds. In addition, the use of brachial artery inflow and straight AVG configuration is associated with steal syndrome. Consideration should be given to construction of access using smaller forearm arteries and looped AVG configuration in patients with high risk for steal. In addition, such patients may require more vigilant monitoring for development of steal after access construction.

Elevated Peak Systolic Velocity and Velocity Ratio from Duplex Ultrasound are Associated with Hemodynamically Significant Lesions in Arteriovenous Access.

BACKGROUND: Duplex ultrasound (DUS) is reliably used to detect lesions in the peripheral and carotid arterial beds and venous system. Although commonly used in clinical practice, duplex criteria to define lesions in arteriovenous access are not well characterized. This study will define the optimal Doppler-derived peak systolic velocity (PSV) and velocity ratio (VR) to identify >50% lesions in arteriovenous fistulas (AVF) and arteriovenous grafts (AVG). METHODS: This retrospective analysis includes patients with both DUS and fistulogram within 30 days. DUS-derived PSV and VR were recorded for 3 segments of each access and compared with fistulograms of the same 3 segments of each AV access. Receiver operating characteristic (ROC) was used to determine the optimal DUS criteria for diagnosis of >50% stenosis. RESULTS: Fifty pairs of imaging in 40 patients were available for analysis. Mean PSV and VR for segments with greater than 50% stenosis were significantly greater than those without; mean PSV of 480 cm/sec vs. 297 cm/sec (P < 0.001) and mean VR of 3.81 vs. 2.09 (P < 0.001). The ROC analysis demonstrated an optimal PSV of 404 and VR of 2.2 to diagnose >50% stenosis with area under the curve of 0.825 and 0.821 for PSV and VR, respectively. PSV of 500 had sensitivity (Se) of 0.60, specificity (Sp) of 0.86, positive predictive value (PPV) of 0.72, and negative predictive value (NPV) of 0.78. VR of 3.0 had Se of 0.52, Sp of 0.91, PPV of 0.77, and NPV of 0.75. CONCLUSIONS: DUS-derived PSV of 400 cm/sec and VR of 2.25 have good discrimination to predict greater than 50% stenosis in AVFs and AVGs. Given the broad range of velocities in AV accesses, a threshold of PSV greater than 500 cm/sec and VR greater than 3.0, will reliably identify graft-threatening lesions. Se and Sp of PSV 500 are 0.596 and 0.854, respectively. Se and Sp for VR 3.0 are 0.519 and 0.894, respectively.

The end stage of dialysis access: femoral graft or HeRO vascular access device.

BACKGROUND: Maintaining and establishing vascular access in end-stage renal disease (ESRD) patients is complicated when they are poor candidates for traditional upper extremity access. Our objective was to compare our experience with 2 alternative dialysis accesses, the femoral arteriovenous graft (fAVG) and the Hemodialysis Reliable Outflow (HeRO), in patients with limited remaining options. METHODS: A single institution, retrospective review of ESRD patients with fAVG or HeRO placed between May 2009 and February 2013 was performed. Adult patients were selected by reviewing all arteriovenous grafts placed at a single institution. Patient demographics, medical history, access characteristics, and outcomes were recorded from both institutional and dialysis center databases. Data were evaluated using Fisher's exact test, unpaired t-test for continuous variables, log-rank test, and univariate analysis. RESULTS: A total of 56 accesses in 43 unique patients met these criteria: 35 fAVG and 21 HeRO; with 1 HeRO patient lost immediately to follow-up. Clinical variables were similar except the HeRO group had more diabetic patients (60% HeRO, 22.9% fAVG; P = 0.01). The average number of years on hemodialysis was 7.0 ± 1.0 for fAVG and 5.7 ± 0.9 for HeRO (P = 0.41). Primary patency was 40.5%, 18.7%, and 14.9% for fAVG and 29.0%, 29.0%, and 0% for HeRO at 6 months, 12 months, and 2 years (P = 0.67), respectively. Assisted primary patency was also similar, with 43.8%, 29.4%, and 13.8% for fAVG and 34.8%, 34.8%, and 17.4% for HeRO at 6 months, 12 months, and 2 years (P = 0.81), respectively. Secondary patency was 62.6%, 50.6%, 19.3% for fAVG and 68.0%, 53.5%, 38.3% for HeRO at 6 months, 12 months, and 2 years (P = 0.69), respectively. Average number of interventions to maintain patency for fAVG was 1.1 ± 1.47 and 1.65 ± 2.52 for HeRO (P = 0.35). Infectious complications occurred in 29% of fAVG and 15% of HeRO (P = 0.33). CONCLUSIONS: Patients who received either fAVG or HeRO experience poor access patency. ESRD patients who receive either of these procedures appear to be at the end stage of available access options.

The use of dextran and carbon dioxide for optical coherence tomography in the superficial femoral artery.

The following case report describes using carbon dioxide (CO2) as contrast media for intravascular optical coherence tomography (OCT) imaging in the superficial femoral artery. For initial OCT imaging, 20 mL of iodinated contrast was used during automated pullback. This was followed by 20 mL of hand-injected dextran 40 in normal saline, and finally hand-injected 50 mL of CO2. CO2 gave comparable erythrocyte clearance and imaging quality compared with dextran and iodinated contrast. To our knowledge, this is the first reported case using both dextran and CO2 with OCT imaging of the superficial femoral artery. Using CO2 is a viable option in patients with contraindications to contrast or dextran use.

Principal considerations for the contemporary high-fidelity endovascular simulator design used in training and evaluation.

BACKGROUND: The simulation and rehearsal of virtual endovascular procedures are anticipated to improve the outcomes of actual procedures. Contemporary, high-fidelity simulation is based on feedback systems that combine concepts of mechanical, electrical, computer, and control systems engineering to reproduce an interactive endovascular case. These sophisticated devices also include psychometric instruments for objective surgical skill assessment. The goal of this report is to identify the design characteristics of commercially available simulators for endovascular procedures and to provide a cross-section comparison across all devices to aid in the simulator selection process. METHODS: Data were obtained (1) by a standard questionnaire issued to four simulator companies prompting for relevant design details of each model for the expressed purpose of publication, (2) from each manufacturer's respective website including appended sales brochures and specification sheets, and (3) by an evaluation of peer-reviewed literature. Focus topics include haptic technology, vessel segmentation, physiologic feedback, performance feedback, and physical logistics (ie, weight, dimensions, and portability). All data sources were surveyed between January 1, 2012, and June 30, 2013. RESULTS: All of the commercially available, high-fidelity endovascular simulators use interactive virtual environments with preprogrammed physics and physiology models for accurate reproduction of surgical reality. The principal differences between devices are the number of access sites and haptic devices, the ability to reconstruct patient-specific anatomy for preprocedural rehearsal, and the available peripheral training modalities. Hardware and software options can also vary within the same device in comparing patient-specific with generic cases. CONCLUSIONS: Despite our limited knowledge about the potential of high-fidelity simulation within the endovascular world, today's currently available simulators successfully provide high-fidelity reproductions of the endovascular environment. We have found that all of the commercially available devices incorporate the necessary features for a high-fidelity experience: (1) haptic technology, (2) vessel reconstruction, (3) physiology feedback, and (4) performance feedback. Significant variations in design do exist and may influence differences in skill development, evaluation, or cost. However, further validation of these differences is still needed and would benefit program directors interested in expanding these platforms for vascular training and certification as this technology matures.

Heparin bonding does not improve patency of polytetrafluoroethylene arteriovenous grafts.

BACKGROUND: Heparin-bonded polytetrafluoroethylene (PTFE) grafts (hepPTFE) were developed to decrease rates of graft thrombosis. Our objective was to compare the patency of arteriovenous grafts (AVGs) for dialysis access with and without heparin bonding in a tertiary care setting. METHODS: Records of patients who had an AVG placed between January 2008 and June 2011 were retrospectively reviewed. Outcome measures were primary, assisted primary, and secondary patency. Marginal survival models (to account for correlation of accesses within subjects) using Cox proportional hazard regression were used for statistical comparisons. RESULTS: A total of 223 patients had 265 grafts placed. Of these, 62 (23%) were hepPTFE grafts. The average age was 66 ± 15 years in the hepPTFE group and 59 ± 17 years in the non-heparin-bonded control group (PTFE; P < 0.01). Of the hepPTFE group, 39% were men, 81% were African American, 63% were diabetic, and 81% had a tunneled catheter at the time of access placement. Of the PTFE group, 35% were men, 85% were African American, 56% were diabetic, and 83% had a tunneled catheter. HepPTFE grafts failed to improve rates of primary, assisted primary, or secondary patency based on univariate analysis (hazard ratio [HR]: 1.37 [95% confidence interval {CI}: 0.99-1.88]; HR: 1.39 [95% CI: 0.98-1.96]; and HR: 1.20 [95% CI: 0.73-1.96], respectively). The number of secondary interventions was similar in the 2 groups (1.1 interventions per person-year of follow-up PTFE versus 1.4 hepPTFE; P = 0.13). A multivariable model including age, diabetes, peripheral artery disease, tobacco use, previous access placement, and tunneled catheter found that the HR for hepPTFE was not significantly different than PTFE in primary, assisted primary, or secondary patency (HR: 1.32 [95% CI: 0.91-1.90]; HR: 1.35 [95% CI: 0.91-1.99]; and HR: 1.15 [95% CI: 0.62-2.16], respectively). CONCLUSIONS: hepPTFE AVGs failed to improve patency or decrease secondary interventions compared to standard PTFE grafts. Prospective studies are needed to confirm these results.

Pulse volume recording does not enhance segmental pressure readings for peripheral arterial disease stratification.

BACKGROUND: Noninvasive vascular laboratory determinations for peripheral arterial disease (PAD) often combine pulse volume recordings (PVRs), segmental pressure readings (SPs), and Doppler waveform traces (DWs) into a single diagnostic report. Our objective was to assess the corresponding diagnostic values for each test when subjected to interpretation by 4 vascular specialists. METHODS: A total of 2226 non-invasive diagnostic reports were reviewed through our institutional database between January 2009 and December 2011. Data from noninvasive records with corresponding angiograms performed within 3 months led to a cohort of 76 patients (89 limbs) for analysis. Four vascular specialists, blinded to the angiographic results, stratified the noninvasive studies as representative of normal, <50% "subcritical," or ≥50% "critical" stenosis at the upper thigh, lower thigh, popliteal, and calf segments using 4 randomized noninvasive modalities: (1) PVR alone; (2) SP alone; (3) SP+DW; and (4) SP+DW+PVR. The angiographic records were independently graded by another 3 evaluators and used as a standard to determine the noninvasive diagnostic values and interobserver agreements for each modality. Statistical tests used include the Fleiss-modified kappa analysis, Kruskal-Wallis analysis of variance with Dunn's multiple comparison test, the Kolmogorov-Smirnov test, and the unpaired t-test with Welch's correction. RESULTS: Interobserver variance for all modalities was high, except for SP. When surveying for any stenosis (<50% and ≥50%), sensitivity (range 25-75%) was lower than specificity (range 50-84%) for all modalities. When surveying for critical stenosis only (≥50%), sensitivity (range 27-54%) was also lower than specificity (range 68-92%). Accuracy for detecting any stenosis with SP+DW was significantly higher than with PVR alone (66 ± 7% vs. 56 ± 12%, P = 0.017). There was a significant reduction in accuracy when including incompressible readings within the SP-only analysis compared with exclusion of incompressible vessels (P = 0.0006). However, the effect of vessel incompressibility on accuracy was removed with the addition of DW (P = 0.17) to the protocol. CONCLUSIONS: SP has the greatest interobserver agreement in evaluation of PAD and can be used preferentially for PAD stratification. Given the lower accuracy of PVR for detecting either subcritical or critical disease, PVR tests can be omitted from the noninvasive vascular examination without a significant reduction in overall diagnostic value and can be reserved for patients with incompressible vessels.

Prevalence, Indications, and Complications of Conversional Surgery After Vertical Banded Gastroplasty: A MBSAQIP Analysis.

PURPOSE: Vertical banded gastroplasty (VBG) was once the most popular bariatric procedure in the 1980's, with many patients subsequently requiring conversional surgery. However, knowledge regarding the prevalence and outcomes of these procedures remains limited. This study aims to determine the prevalence, indications, rate of 30-day serious complications, and mortality of conversional surgery after VBG. MATERIALS AND METHODS: A retrospective analysis of the MBSAQIP database from 2020 to 2022 was conducted. Individuals undergoing conversional or revisional surgery after VBG were included. The primary outcomes were 30-day serious complications and mortality. RESULTS: Of 716 VBG conversions, the common procedures included 660 (92.1%) Roux-en-Y gastric bypass (RYGB) and 56 (7.9%) sleeve gastrectomy (SG). The main indication for conversion was weight gain for RYGB (31.0%) and for SG (41.0%). RYGB had longer operative times than SG (223.7 vs 130.5 min, p < 0.001). Although not statistically significant, serious complications were higher after RYGB (14.7% vs 8.9%, p = 0.2). Leak rates were higher after SG (5.4 vs 3.5%) but this was not statistically significant (p = 0.4). Mortality was similar between RYGB and SG (1.2 vs 1.8%, p = 0.7). Multivariable regression showed higher body mass index, longer operative time, previous cardiac surgery and black race were independently associated with serious complications. Conversion to RYGB was not predictive of serious complications compared to SG (OR 0.96, 95%CI 0.34-2.67, p = 0.9). CONCLUSIONS: Conversional surgery after VBG is uncommon, and the rate of complications and mortality remains high. Patients should be thoroughly evaluated and informed about these risks before undergoing conversion from VBG.

Prescribing patterns of antiplatelet agents are highly variable after lower extremity endovascular procedures.

BACKGROUND: The use of antiplatelet and antithrombotic agents after peripheral vascular interventions is a common clinical practice despite a lack of clear convincing evidence or accepted practice guidelines. The goal of this study was to assess surgeons' prescribing practices after endovascular procedures for lower extremity arterial occlusive disease. METHODS: Attendees at a national vascular meeting were asked to complete a voluntary survey indicating their prescribing practices of antiplatelet/antithrombotic agents for the following procedures: iliac bare-metal stent, iliac covered stent, infrainguinal balloon angioplasty, infrainguinal bare-metal stent, infrainguinal covered stent, infrainguinal atherectomy, and lower extremity cryoplasty. The respondents were given choices of aspirin (ASA) alone, clopidogrel alone, ASA/clopidogrel combined, warfarin alone, or ASA/clopidogrel/warfarin combined. They were also asked to indicate their preferred length of treatment for each medication or combination of medications for each procedure: 1, 3, 6, or 12 months. RESULTS: There were 51 respondents (48 vascular surgeons and 3 vascular fellows) with an average of 11 ± 6.4 years of experience and practicing in a university hospital (48%), community hospital (44%), or combined university/Veterans A hospital (6%) setting. The majority of respondents (98%) prescribe an antiplatelet agent for patients with peripheral arterial disease using 81 mg of ASA preferentially. Most surgeons do not obtain genetic testing (i.e., cytochrome P450, polypeptide 19 [CYP2C19] polymorphism) for antiplatelet effectiveness. The most common antiplatelet/antithrombotic medication of choice after lower extremity endoluminal therapy was a combination of ASA/clopidogrel. However, the duration of medical treatment was variable, with a 1- to 3-month course being the most common. The use of the ASA/clopidogrel combination increased with further distal endovascular treatment and the placement of stents versus angioplasty. In the vast majority of ASA-only responses, ASA was administered for at least 12 months if not recommended for life. Although the majority of surgeons would recommend dual antiplatelet therapy (52-77%), there was no consensus regarding the duration of treatment. CONCLUSIONS: The antiplatelet/antithrombotic prescribing practices of vascular surgeons after lower extremity endovascular procedures are highly variable. Multicenter randomized controlled trials are needed to define optimal treatment efficacy and define the much-needed practice guidelines.

Predicting serious complications following bariatric surgery in geriatric patients: development of the GeriBari scoring tool using the MBSAQIP database.

BACKGROUND: Geriatric patients have a greater risk of complications after bariatric surgery. The objective of this study was to develop a tool to predict serious complications in geriatric patients after minimally invasive bariatric surgery. OBJECTIVES: To develop a predictive model, GeriBari, for serious complications in geriatric patients after bariatric surgery. SETTING: Multiple accredited bariatric surgery centers in the United States and Canada. METHODS: This was a retrospective cohort study of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database, which collects 30-day bariatric surgery outcomes from 868 accredited centers. Geriatric patients defined as those ≥65 years old who underwent primary laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) were included. Characteristics associated with serious complications were identified using univariate and multivariable analyses. A predictive model, GeriBari, was derived using a forward selection algorithm from operative years 2015, 2017, and 2019. GeriBari's robustness was tested against a validation cohort of subjects from operative years 2016 and 2018. RESULTS: A total of 40,199 geriatric patients underwent LRYGB (27.7%) or LSG (72.3%). Overall, 1866 (4.6%) experienced a complication, which included bleeding (1.6%), reoperation (1.6%), reintervention (1.3%), unplanned intubation (.4%), and pneumonia (.4%). Mortality was higher in the geriatric patients than that in younger patients (.27% versus .08%). GeriBari consists of 12 factors that predicted serious complications and stratified individuals into high- (>6%) and low-risk (<6%) groups. This tool accurately predicted events in the validation cohort with sensitivity of 46.0% and specificity of 100%. CONCLUSIONS: GeriBari enables preoperative risk stratification for 30-day serious complications in geriatric patients undergoing bariatric surgery. Stratifying low- and high-risk geriatric patients for adverse events allows for informed clinical decision-making prior to bariatric surgery.