Gastric Mass: Intramural Hematoma.

Gastric masses can be challenging to diagnose pre-operatively due to their heterogeneity in presentation and work-up. One must be cautious that a seemingly benign mass may be malignant and vice versa. Some of the more common gastric masses include peptic ulcer, adenocarcinoma, and gastrointestinal stromal tumour. These diagnoses have vastly different management strategies despite similar presentations. The case presented here is an example of this management, highlighting a patient with a gastric bleeding mass initially thought to be a gastrointestinal stromal tumour. However, on final pathology, the mass was determined to be benign, an ulcerated hematoma.

Spontaneous Hemoperitoneum From a Ruptured Gastrointestinal Stromal Tumor.

This is a case report of a ruptured gastrointestinal stromal tumor (GIST) presenting as spontaneous hemoperitoneum. The patient was a 63-year-old female with a past medical history of hypertension and ulcerative colitis who presented to the emergency department with worsening epigastric pain. The patient denied history of trauma, previous surgeries, or forceful vomiting. She was not on anticoagulation. Vital signs at presentation were stable. A CT scan of abdomen/pelvis revealed a large amount of fluid in the upper abdomen with high attenuation material adjacent to the greater curvature of the stomach concerning for hemoperitoneum. Diagnostic laparoscopy revealed a significant amount of blood along the upper abdominal viscera. The procedure was converted to an upper midline laparotomy after identifying a necrotic, extremely friable 7 x 6 x 3 cm pedunculated mass with active hemorrhage on the posterior aspect of the greater curvature. A wedge resection was performed to remove the mass with grossly negative margins. An intraoperative frozen section revealed a stromal tumor with spindle cells. Final pathology revealed a pT3N0M0 stromal tumor with histologic spindle cells and a high mitotic rate (24/5 mm2) consistent with a high-grade GIST. Given tumor rupture at presentation, the patient was started on imatinib therapy for a minimum duration of three years. GISTs are often asymptomatic or cause mild abdominal pain or GI bleeding. Rarely, an exophytic GIST may rupture leading to intraperitoneal bleeding. Surgical resection with negative margins is the mainstay of treatment although patients presenting with tumor rupture are at higher risk of dissemination and recurrence.

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.

Completion Gastrectomy with Esophagojejunostomy for Management of Complications of Benign Foregut Surgery.

BACKGROUND: With the worldwide epidemic of obesity, an increasing number of bariatric operations and antireflux fundoplications are being performed. Despite low morbidity of the primary foregut surgery, completion gastrectomy may be necessary as a definitive procedure for complications of prior foregut surgery; however, the literature evaluating outcomes after completion gastrectomy with esophagojejunostomy (EJ) for benign diseases is limited. We present our experience of completion gastrectomy with Roux-en-Y EJ in the setting of benign disease at a single tertiary center. METHODS AND PROCEDURES: All patients who underwent total, proximal, or completion gastrectomy with EJ for complications of benign foregut surgery from January 2006 to December 2015 were retrospectively identified. All cancer operations were excluded. RESULTS: There were 23 patients who underwent gastrectomy with EJ (13 laparoscopic EJ [LEJ] and 10 open EJ). The index operations included 12 antireflux, 9 bariatric, and 2 peptic ulcer disease surgeries. Seventy-eight percent of patients had surgical or endoscopic interventions before EJ, with a median of one prior intervention and a median interval from the index operation to EJ of 25 months (interquartile range 9-87). The 30-day perioperative complication rate was 30% with 17% classified being major (Clavien-Dindo ≥ III) and no 30-day perioperative mortality. Comparing laparoscopic and open approaches showed similar operative times, estimated blood loss, and overall complication rate. LEJ was associated with a shorter length of stay (LOS) (P < .001), fewer postoperative ICU days (P = .002), fewer 6-month complication rates (P < .007), and decreased readmission rate (P = .024). CONCLUSION: Our series demonstrates that EJ is a reasonable option for reoperative foregut surgery. The laparoscopic approach appears to be associated with decreased LOS and readmissions.

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.

How I Do It: Per-Oral Pyloromyotomy (POP).

INTRODUCTION: Several surgical treatments exist for treatment of gastroparesis, including gastric electrical stimulation, pyloroplasty, and gastrectomy. Division of the pylorus by means of endoscopy, Per-Oral Pyloromyotomy (POP), is a newer, endoluminal therapy that may offer a less invasive, interventional treatment option. METHODS: We describe and present a video of our step by step technique for POP using a lesser curvature approach. The following are technical steps to complete the POP procedure from the lesser curve approach. CONCLUSION: In our experience, these methods provide promising initial results with low operative risks, although long-term outcomes remain to be determined.

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.

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.

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.

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.

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.

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.

Arteriovenous grafts have higher secondary patency in the short term compared with autologous fistulae.

BACKGROUND: To estimate patency of arteriovenous fistulas (AVFs) and grafts (AVGs) for dialysis access. METHODS: Records of all adult patients who had a dialysis access placed from January 2008 to June 2011 were retrospectively reviewed. RESULTS: A total of 494 patients with 655 accesses (390 AVFs, 265 AVGs) were examined. We found that AVG fared worse in assisted primary patency. But AVG had superior secondary patency up to 1.2 years (hazard ratio [HR] .6, confidence interval [CI]: [.4 to .8]) and was no different than AVF after 1.2 years. (HR 1.6, CI: [.9 to 3.1]). On univariate analysis, dialysis catheters negatively impacted assisted primary patency (HR 1.4, CI: [1.09 to 1.77]). CONCLUSIONS: AVG can be maintained with higher rates of secondary patency in the short term and are no different in the long term. This result suggests that in patients with limited life expectancy an AVG may be an effective alternative to an AVF to reduce both catheter time and associated complications.

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.

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.

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.

Lower extremity amputations: factors associated with mortality or contralateral amputation.

BACKGROUND: Tissue loss or gangrene in the setting of lower extremity peripheral artery disease (PAD) may result in amputation. Previous studies have demonstrated elevated mortality rates after major transtibial and transfemoral amputation. Also, amputation of 1 leg may be associated with subsequent major amputation of the contralateral leg. The aim of our study was to identify patient variables associated with mortality and contralateral amputation. METHODS: We reviewed the medical records of patients who underwent transfemoral or transtibial amputation secondary to PAD from 2004 to 2009. A total of 454 consecutive major amputations were performed on 391 patients, with 63 of these having a subsequent contralateral amputation. Standard demographic information, comorbidities, prior vascular interventions, and relevant procedural information were extracted from patient records. Kaplan-Meier estimates of survival were calculated. Cox proportional hazard models were used to estimate the risk of death and contralateral amputation. Multivariate Cox proportional hazards models were fit for all variables shown to be marginally associated in the univariate model. RESULTS: In 391 amputees, the mean age was 67.3 years, 63% were male and 62% were caucasian. Patients had high rates of diabetes (63%), hypertension (83%), renal insufficiency (35%), hyperlipidemia (51%), and prior ipsilateral vascular intervention (75%). Seventy percent of patients had below-knee amputations. Perioperative mortality was 9.2% (n = 36). Survival at 12 and 24 months was 70% (95% confidence interval [CI], 65%-74%) and 60% (95% CI, 55%-65%), respectively. Multivariate analysis demonstrated that several independent factors were detrimental to survival including chronic obstructive pulmonary disease (hazard ratio [HR] 1.82, P = .002), dialysis dependence (HR 2.50, P < .001), high cardiac risk (HR 2.20, P < .001), and guillotine amputation (HR 2.49, P = .004). Dialysis (HR 2.42, P = .002) and revision of the index ipsilateral amputation to a higher level (HR 2.02, P = .014) were associated with a subsequent contralateral amputation. CONCLUSIONS: Patients with advanced PAD that require lower extremity amputation have diminished survival and significant contralateral amputation rates. Elderly patients on dialysis are particularly prone to dying or losing the other leg after a major amputation. These data support strategies to enhance limb preservation and optimize medical comorbidities in these patients.

Levothyroxine replacement dosage determination after thyroidectomy.

BACKGROUND: The goal of this study was to identify a simple and effective way of calculating levothyroxine doses for postsurgical hypothyroidism. METHODS: Levothyroxine dosage was calculated using a weight (µg/kg)-based formula for patients who underwent thyroidectomy for benign disease from 2001 to 2011. Other formulas using age, sex, ideal body weight, body mass index, and body surface area were also evaluated. RESULTS: Four hundred four patients were included; 85% were women. The mean initial levothyroxine dosage was 1.4 µg/kg, which resulted in thyroid-stimulating hormone normalization in 59%, suppression in 23%, and elevation in 18% of patients. After dose adjustments, the mean therapeutic levothyroxine doses after total thyroidectomy and lobectomy were 1.5 and 1.3 µg/kg, respectively. A regression model incorporating other patient factors did not produce a more reliable dosing regimen. CONCLUSION: A 1.5- and 1.3-µg/kg dosage calculation based on actual weight is currently the best estimation for levothyroxine replacement therapy after thyroidectomy.