BBI Contributing Writer

CHICAGO, Illinois – Keen interest was focused on laparoscopic gastric bypass at the 86th annual clinical congress of the American College of Surgeons (ACS; Chicago, Illinois), held in its home city in late October. Gastric bypass is a surgical procedure for morbidly obese patients that basically reduces the size of the stomach to 15 cc capacity and re-routes the small intestine into the bowel. After five years of closely following patients who underwent laparoscopic Roux-en-Y (the most commonly used technique for gastric bypass), it can be said that not only do the patients lose 80% of their excess weight in the first year, but more importantly over 95% of their co-morbidities were controlled. For these reasons, this procedure was very popular in both clinical presentations and vendor exhibits at the ACS gathering.

Drs. Alan Wittgrove and G. Wesley Clark from Alvarado Hospital and Medical Center (San Diego, California) started performing gastric bypass operations using laparoscopic methods in 1993. They have performed the Roux-en-Y gastric bypass procedure on 6,000 patients using the conventional open technique and 1,100 patients using a laparoscopic technique. They have followed their first 500 patients who had the procedure performed using the laparoscopic technique over five years. They found the results to be remarkable, with procedure times down to a one-hour (two hours maximum), two-day length-of-stay, 96% co-morbidities eliminated (see Table 4 on page 13) and 80% of excess weight lost at year one and maintained over five years. These results and other factors are driving great interest on behalf of patients, surgeons, payors and medical device manufacturers (Table 5).

There are strict guidelines governing the patients admitted for bariatric surgery, determined by the National Institutes of Health (Bethesda, Maryland), American Society for Bariatric Surgery (Gainesville, Florida) and International Federation for the Surgery of Obesity. In brief, candidates must be 100 pounds overweight, along with other measurable physical criteria, or have co-morbidities that are life-threatening or detrimental to normal activities of daily life.

Key players that have developed tools specifically for the laparoscopic Roux-en-Y procedure include Ethicon EndoSurgery (Cincinnati, Ohio), with disposable products; Richard Wolf Medical Instruments (Vernon Hills, Illinois), with a reusable instrument set designed by Drs. Wittgrove & Clark; and Karl Storz (Culver City, California), with a reusable generic set of instruments. Richard Wolf also is co-marketing the Vista, a 3-D video system that allows the surgeon to view the surgical field three-dimensionally through a headset, thus enhancing the laparoscopic technique. According to Clark, who now has his laparoscopic operating time down to match that of his conventional open operating time, the Vista system allows the surgeon to move quicker and with more efficiency.

Bravo for the Bravo system

About 50 million Americans have some form of gastroesophageal reflux disease, commonly referred to as GERD. Of these, around 14 million suffer chronically and three million of those will be referred for endoscopy, a diagnostic tool that allows the physician an opportunity to visually confirm GERD. However, about half the time no visual confirmation of esophagitis (indication that GERD exists) can be made, leaving a pH study as the final tool to definitively diagnose GERD. Traditionally pH monitoring involves another trip to the hospital for another somewhat invasive test. A nasal esophageal catheter is placed into the esophagus and is worn by the patient while being monitored for 24 hours.

For these reasons, there was a lot of activity at the Endonetics (San Diego, California) booth during the ACS conference. Endonetics received 510(k) clearance to market the first catheter-free pH monitoring system, the Bravo, in September 2000. It has conducted a controlled product launch at several U.S. sites and anticipates expanding to a full product launch in 1Q01. The Bravo probe is attached to the esophagus using a proprietary delivery system, preferably at the time of endoscopy. The probe then transmits pH data via radio telemetry signals that are recorded by the receiver, which is worn by the patient like a beeper. Within days, the probe sloughs off the wall of the esophagus and passes through the patient's gastrointestinal tract. The real beauty of this product is that it eliminates the patient having to return to the hospital for additional testing, and also eliminates the patient having to wear a nasal catheter for 24 hours.

Currently, only 10% of the patients who undergo an endoscopy and have negative findings actually have pH monitoring performed. Many professionals believe that one of the key reasons the compliance is so low is because the patients are averse to wearing the trans-nasal catheter for 24 hours. With the Bravo system, it is expected that patient compliance with the request for pH monitoring could increase to 50% (see Table 6). In side-by-side testing with Medtronic's (Minneapolis, Minnesota) current catheter product, Endonetics said the Bravo system is demonstrating consistent and equivalent results. The other current major market leader in traditional pH monitoring is Sandhill Scientific (Highland Park, Colorado).

The Bravo system dovetails nicely into Endonetics' next product – the Gatekeeper Reflux Repair System, which will address the therapeutic side of GERD. The Gatekeeper is an endoscopically delivered prosthesis placed in the esophageal wall that creates the effect of a pseudo valve. It was expected to be in clinical trials by year-end 2000.

Drugs may impact surgical subspecialties

In a paper delivered at the general session, Dr. Judah Folkman (Boston, Massachusetts) suggested that a new class of drugs may have an effect that spans several surgical subspecialties and change current treatment protocols. This new class of drugs is called angiostatins and they stop angiogenesis, or blood vessel growth. Most cancerous tumors depend on angiogenesis to provide blood supply to the tumor, so current cancer treatment protocols (i.e. surgery) could be impacted if it is proven that angiostatins block blood vessel growth in human tumors, causing them to die of oxygen starvation.

In addition to cancer, there are other diseases throughout the body that are angiogenesis-dependent – that is, dependent on new blood vessel growth. Many of these diseases currently use some surgical component in their treatment protocol that could be eliminated if angiostatins reach their full potential. Some of these are macular degeneration, endometrioses, psoriasis, arthritis, diabetic retinopathy and Crohn's disease. These angiogenic diseases recruit new blood vessels to grow abnormally.

Drug companies have found that it is easier to turn off angiogenesis than to turn it on. A prime example of failed attempts to create angiogenesis is in the heart, where researchers are trying to grow new coronary blood vessels. But in more than 20 clinical trials in patients that have advanced solid tumors, researchers are finding that it is easy to stop angiogenesis with angiostatins. The process starts in about four weeks following the initial administration of an angiostatin and takes about one year to completely eliminate the tumor. They have found no effect on the liver, few side effects at all and no effect on wound healing. Researchers also have found that angiostatins plus radiation have a synergistic effect. However, once the angiostatin is stopped, the tumor returns. The future hope is that angiostatins will first be used as an adjunct to current surgical therapies and eventually be used as preventive agents for cancers and other diseases.