Device-assisted Enteroscopy for Obscure Gastrointestinal Bleeding in the Setting of Thienopyridine Antiplatelet Therapy.

BACKGROUND: Current guidelines recommend suspending thienopyridine therapy 5 to 7 days before therapeutic endoscopy to reduce the risk of bleeding-related complication. However, interruption of antiplatelet therapy may increase the risk of a cardiovascular event. The aim of this study was to evaluate the safety and diagnostic yield of device-assisted enteroscopy (DAE) with endoscopic therapy in patients receiving thienopyridine antiplatelet therapy. MATERIALS AND METHODS: A retrospective chart review was performed for patients treated in the LSU Health Sciences Gastroenterology Clinics between the dates of October 4, 2007 and February 15, 2015. A total of 774 enteroscopy procedures were reviewed to identify patients on active thienopyridine therapy at the time of DAE. RESULTS: During the study period, a total of 68 patients underwent DAE while on thienopyridine therapy. Confirmed or suspected small bowel bleeding was the most common procedural indication. A total of 143 endoscopic interventions were performed, primarily argon plasma coagulation for ablation of intestinal angioectasias. There were no significant bleeding-related complications associated with these procedures. In addition, the diagnostic yield for these procedures was high (77%) with a significant percentage of patients in the thienopyridine group found to have an active bleeding source at the time of DAE. CONCLUSIONS: The performance of DAE procedures with endoscopic intervention such as argon plasma coagulation may be safe in patients on thienopyridine therapy. Continuing thienopyridines may also increase the diagnostic yield of these procedures by promoting active bleeding from the culprit source.

Cyclotron Production of High-Specific Activity 55Co and In Vivo Evaluation of the Stability of 55Co Metal-Chelate-Peptide Complexes.

This work describes the production of high-specific activity 55Co and the evaluation of the stability of 55Co-metal-chelate-peptide complexes in vivo. 55Co was produced via the 58Ni(p,α)55Co reaction and purified using anion exchange chromatography with an average recovery of 92% and an average specific activity of 1.96 GBq/µmol. 55Co-DO3A and 55Co-NO2A peptide complexes were radiolabeled at 3.7 MBq/µg and injected into HCT-116 tumor xenografted mice. Positron emission tomography (PET) and biodistribution studies were performed at 24 and 48 hours postinjection and compared to those of 55CoCl2. Both 55Co-metal-chelate complexes demonstrated good in vivo stability by reducing the radiotracers' uptake in the liver by sixfold at 24 hours with ~ 1% ID/g and at 48 hours with ~ 0.5% ID/g and reducing uptake in the heart by fourfold at 24 hours with ~ 0.7% ID/g and sevenfold at 48 hours with ~ 0.35% ID/g. These results support the use of 55Co as a promising new radiotracer for PET imaging of cancer and other diseases.

Harvesting (67)Cu from the Collection of a Secondary Beam Cocktail at the National Superconducting Cyclotron Laboratory.

Isotope harvesting is a promising new method to obtain isotopes for which there is no reliable continuous supply at present. To determine the possibility of obtaining radiochemically pure radioisotopes from an aqueous beam dump at a heavy-ion fragmentation facility, preliminary experiments were performed to chemically extract a copper isotope from a large mixture of projectile fragmentation products in an aqueous medium. In this work a 93 MeV/u secondary beam cocktail was collected in an aqueous beam stop at the National Superconducting Cyclotron Laboratory (NSCL) located on the Michigan State University (MSU) campus. The beam cocktail consisted of ∼2.9% (67)Cu in a large mixture of co-produced isotopes ranging in atomic number from ∼19 to 34. The chemical extraction of (67)Cu was achieved via a two-step process: primary extraction using a divalent metal chelation disk followed by anion-exchange chromatography. A significant fraction (74 ± 4%) of the (67)Cu collected in the aqueous beam stop was recovered with >99% radiochemical purity. To illustrate the utility of this product, the purified (67)Cu material was then used to radiolabel an anti-EGFR antibody, Panitumumab, and injected into mice bearing colon cancer xenografts. The tumor uptake at 5 days postinjection was found to be 12.5 ± 0.7% which was in very good agreement with previously reported studies with this radiolabeled antibody. The present results demonstrate that harvesting isotopes from a heavy-ion fragmentation facility could be a promising new method for obtaining high-quality isotopes that are not currently available by traditional methods.

Distribution of bleeding gastrointestinal angioectasias in a Western population.

AIM: To define which segments of the gastrointestinal tract are most likely to yield angioectasias for ablative therapy. METHODS: A retrospective chart review was performed for patients treated in the Louisiana State University Health Sciences Center Gastroenterology clinics between the dates of July 1, 2007 and October 1, 2010. The selection of cases for review was initiated by use of our electronic medical record to identify all patients with a diagnosis of angioectasia, angiodysplasia, or arteriovenous malformation. Of these cases, chart reviews identified patients who had a complete evaluation of their gastrointestinal tract as defined by at least one upper endoscopy, colonoscopy and small bowel capsule endoscopy within the past three years. Patients without evidence of overt gastrointestinal bleeding or iron deficiency anemia associated with intestinal angioectasias were classified as asymptomatic and excluded from this analysis. Thirty-five patients with confirmed, bleeding intestinal angioectasias who had undergone complete endoscopic evaluation of the gastrointestinal tract were included in the final analysis. RESULTS: A total of 127 cases were reviewed. Sixty-six were excluded during subsequent screening due to lack of complete small bowel evaluation and/or lack of documentation of overt bleeding or iron deficiency anemia. The 61 remaining cases were carefully examined with independent review of endoscopic images as well as complete capsule endoscopy videos. This analysis excluded 26 additional cases due to insufficient records/images for review, incomplete capsule examination, poor capsule visualization or lack of confirmation of typical angioectasias by the principal investigator on independent review. Thirty-five cases met criteria for final analysis. All study patients were age 50 years or older and 13 patients (37.1%) had chronic kidney disease stage 3 or higher. Twenty of 35 patients were taking aspirin (81 mg or 325 mg), clopidogrel, and/or warfarin, with 8/20 on combination therapy. The number and location of angioectasis was documented for each case. Lesions were then classified into the following segments of the gastrointestinal tract: esophagus, stomach, duodenum, jejunum, ileum, right colon and left colon. The location of lesions within the small bowel observed by capsule endoscopy was generally defined by percentage of total small bowel transit time with times of 0%-9%, 10%-39%, and 40%-100% corresponding to the duodenum, jejunum and ileum, respectively. Independent review of complete capsule studies allowed for deviation from this guideline if capsule passage was delayed in one or more segments. In addition, the location and number of angioectasias observed in the small bowel was further modified or confirmed by subsequent device-assisted enteroscopy (DAE) performed in the 83% of cases. In our study population, angioectasias were most commonly found in the jejunum (80%) followed by the duodenum (51%), stomach (22.8%), and right colon (11.4%). Only two patients were found to have angioectasias in the ileum (5.7%). Twenty-one patients (60%) had angioectasias in more than one location. CONCLUSION: Patients being considered for endoscopic ablation of symptomatic angioectasias should undergo push enteroscopy or anterograde DAE and re-inspection of the right colon.