New GI technologies improve internal organ visualization

As visualization technologies like ultrasound continue to improve in quality and safety, researchers are making the most of the opportunity to access new areas of internal organs that have not previously been examined without open surgery. In a group of studies presented today during Digestive Disease Week® 2006 (DDW), endoscopic procedures are demonstrating significant improvements in the quality and delivery of evaluation, diagnosis and treatment of the GI tract and surrounding areas. DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

The Heart – An Easily Accessible and Safe Target for Endoscopic Ultrasound and Fine Needle Intervention? [Abstract W1277]

Procedures involving the heart can be complicated and dangerous for the patient, but the use of technologies that can improve visualization of the area can increase the accuracy of the interventions. The heart's close proximity to the wall of the esophagus has led researchers to study the possible benefit of endoscopic ultrasound to visualize the heart and help guide interventions.

This study by researchers at Homerton University Hospital in London focused on the feasibility and safety of trans-esophageal punctures and interventions into the heart and coronary arteries in six pigs and two human patients. Endoscopic ultrasound (EUS) is frequently performed with a scope to visualize and detect abnormalities in the GI tract.

Using EUS to guide them, researchers punctured the myocardium and aortic valve or coronary artery in the six pigs; three received angiography and three received thermal ablation, or clearing of the aortic valve. The repeat puncture of the cardiac walls and injection of contrast to help visualize the tissues showed no complications, nor did the angiography or thermal ablation procedures. EUS-guided fine-needle aspiration, or removal of heart tissue for examination, was conducted in the two human patients, also showing no arrhythmia or other complications.

"Our studies suggest that using a trans-esophageal process to gain access to the heart may be feasible and safe for patients as an alternative to the much longer, indirect route through the femoralis artery in the groin or to open surgery," said Annette Fritscher-Ravens, M.D., of the Homerton University Hospital and lead study author. "This may be of specific interest for patients who have damaged heart muscle after a heart attack and may benefit from the injection of therapies directly into the muscle without another operation."

Endoscopic Ultrasound (EUS)-Guided Angiography: A Novel Approach to Diagnostic and Therapeutic Intervention in the Vascular System [Abstract W1321]

The human vascular system represents a unique highway that allows access to every part of the body, and problems with the system can result in serious health conditions. The ability to safely intervene, diagnose, and treat vascular abnormalities with minimally-invasive techniques represents significant advances in the practice of medicine.

In this study, researchers review the technical challenges and potential value of an endoscopic ultrasound (EUS)-guided angiography. Endoscopic ultrasonography is the practice of using an ultrasound transducer at the tip of an endoscope to visualize and offer therapeutic intervention to the gastrointestinal tract and its surrounding structures, which includes nearby vasculature and organs.

The researchers tested the feasibility of EUS to perform angiography in three pigs. EUS was conducted on each pig to identify major blood vessels, including the thoracic and abdominal aorta, celiac axis, superior mesenteric artery, splenic vein, portal vein, splenic artery and hepatic veins. During the EUS, the researchers injected contrast to improve vascular visualization, and - performed angiography using several different gauge aspirate needles (19g, 22g and 25g). Pigs were then euthanized to examine the results.

The process demonstrated excellent visualization of the vasculature, and without any technical difficulties in injecting each artery. The 25g needle did not cause any visible vascular damage, though the 22g needle caused a puncture and the 19g needle caused limited bleeding. The contrast injection was easiest with the 19g needle and most difficult with the 25g needle. In each case, however, EUS-guided angiography successfully and clearly highlighted the vessels.

"We feel that based on the results of this study as well as the close proximity of the intestinal wall to vasculature, an EUS-guided approach to perform selective angiography is feasible. Safe access to the vasculature is just the first step to performing EUS-guided therapeutic intervention throughout the vasculature," said Sanjay Jagannath, M.D., of Johns Hopkins Hospital and co-author of the study. "We plan further research in the near future so that this technique may one day be more widely used in the human arena."

Double Balloon Enteroscopy (DBE) Compared to Capsule Endoscopy (CE) Among Patients with Obscure Gastrointestinal Bleeding (OGIB): A Multicenter US Experience [Abstract 495]

Two new endoscopic procedures have been utilized recently to examine the small intestine for abnormalities or diseases: capsule endoscopy (CE) and double balloon enteroscopy (DBE). In this study, researchers compared the two procedures for accuracy in diagnosing intestinal bleeding.

During a capsule endoscopy, the patient swallows a small camera that records images of the intestinal tract. To complete a double balloon enteroscopy, doctors use a scope fitted with two balloons to navigate the entire small bowel. When inflated with air, the balloons can expand sections of the small intestine to allow the camera a closer examination.

In the multicenter study, DBE was conducted in 130 patients. Of these patients, 115 had previously undergone CE, which had found potential bleeding site in 63 of these patients and negative results in the other 52 patients. The DBE results showed a bleeding site in two-thirds (41 pts) of the patients who had the same reading by CE, and one-third (16 pts) in the group who had clean CE. DBE was also able to treat all nearly all the bleeding sites found.

Overall, the two procedures were considered moderately effective in detecting sources of intestinal bleeding. Efficacy rates for DBE and CE were comparable in detecting ulcers, blood vessel abnormalities that cause bleeding and large masses, but DBE was more effective in detecting mucosal and submucosal polyps. DBE was also a more lengthy process, averaging 94 minutes, whereas CE averaged 44 minutes. As opposed to CE, DBE did not read the entire small bowel in a single procedure, but it did detect abnormalities in one-third of patients with negative CE results.

"Both procedures offer value to patients with unknown sources of intestinal bleeding or other small bowel problems, and should be used to help evaluate a patient's health," said Shahab Mehdizadeh, M.D., of Cedars-Sinai Medical Center and lead study author. "Clearly, DBE has the advantage of being able to treat problems. But we believe that based on the results of this study, CE should continue to be used as a valuable regular screening test for bowel abnormalities, while DBE will be a better procedure for conformation and treatment of small-bowel problems."

Feasibility Assessment of Computer Assisted Personalized Sedation: A Sedation Delivery System to Administer Propofol for Gastrointestinal Endoscopy [Abstract T1304]

As computer programs become further integrated into the medical setting, researchers are looking for new ways to utilize these technologies to increase procedural effectiveness and accuracy. Scientists from Charlottesville Medical Research in Virginia, have continued this trend to monitor and deliver sedation during surgery with computer assisted personalized sedation (CAPS), which uses computer software to facilitate precise control of drug delivery.

Anesthesiologists and physician/nurse care teams in the study first injected 24 patients (12 colonoscopy and 12 endoscopy) with a single dose of fentanyl as pre-medication, then administered propofol using the CAPS system and its dosing algorithm and safety shell--a control safeguard software program. Data was downloaded from the sedation device to a laptop computer to measure patient response throughout the procedure and adjust the sedation dosage accordingly. Patient responsiveness was monitored by the anesthesiologist using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale and the Automated Responsiveness Monitor (ARM) device. The MOAA scale assesses the patient's level of sedation from alert to only responding to a painful stimulus, and the ARM is a handheld device that the patient squeezes on command from a voice from an earpiece in the patient's ear. This response helps determine the level of sedation.

All procedures were completed successfully and six patients had at least one polyp removed. Of the 24 patients, 14 (7 colonoscopy and 7 endoscopy) lost responsiveness to ARM during the procedure. One subject experienced oxygen desaturation (level of breathing and sedation) below 90 percent (low=85 percent) and seven subjects experienced apnea for less than 30 seconds. However, the device automatically responded to these adverse physiological reactions by adjusting sedation amounts and all eight subjects recovered to normal respiratory parameters without intervention by the anesthesiologist.

"This new technology represents an exciting breakthrough in the use of computers to properly administer and monitor sedation in patients undergoing a variety of procedures," said Daniel Pambianco, M.D., Charlottesville Medical Research and lead study author. "When used with a trained anesthesiologist, this device may help manage the potential risks associated with sedation and ensure that each patient is cared for based on their own needs."

Source : American Gastroenterological Association