LOUISVILLE In the field of gastroenterology, innovations in endoscopy and minimally invasive surgery have led to much improved results and quality of life for patients. UofL Health is a vanguard of this medical movement. According to Nathan Liu, MD, “The University of Louisville is on the forefront of doing these advanced procedures. We are able to do things that nearby states are not doing at this time. We’re able to do procedures that we weren’t able to do in the past.”
Along with the ongoing treatment of more common conditions, such as GERD (gastric reflux), celiac disease, and irritable bowel syndrome, the gastroenterologists within UofL Health address the most complex conditions—using the latest therapeutic agents, endoscopic procedures, and surgical techniques to combat Crohn’s disease, gastroparesis, and the full range of gastrointestinal cancers (colorectal, esophageal, gastric, small bowel, pancreatic, and liver).
Liu is an interventional gastroenterologist and an assistant professor of medicine for UofL. Hailing from Athens, Georgia, Liu did his undergraduate studies in biology and chemistry at Emory University in Atlanta, then remained in Georgia to attend the Medical College of Georgia. Following that, Liu moved to Louisville, where he completed a residency in internal medicine and a three-year fellowship in gastroenterology. He then did an additional 18 months of training in advanced therapeutic endoscopy and a submucosal fellowship at the University of Florida in Gainesville.
His journey to becoming a physician began when his younger brother was diagnosed with Kawasaki’s disease as a child. Liu says, “It was my first real experience with medicine. And when the doctors were able to make a quick diagnosis for him and get him treated, it prevented irreversible damage to his heart and arteries.” Initially, Liu envisioned himself as a cardiothoracic pediatric surgeon. But during his first year of medical school, he was introduced to gastroenterology and has not looked back. As for his brother, he continues to thrive and just graduated medical school last year.
Improved Techniques and Technologies
In his role as an interventional gastroenterologist, Liu sees patients ranging from 16 years of age up to octogenarians. He states, “I perform EGD [esophagogastroduodenoscopy], colonoscopies and screening colonoscopies. I do endoscopic ultrasound, which helps to diagnose pancreatic cancer. I also do ERCP [endoscopic retrograde pancreatography], which allows us to remove stones in the bile duct.”
In addition, because of his expertise in complicated colon polyps, Liu often receives referrals from other surgeons and gastroenterologists for more extensive higher-risk polyps for removal. While at the University of Florida, Liu was trained in endoscopic submucosal dissection (ESD), developed in Japan, which allows him to perform minimally invasive surgery within the colon walls. If a polyp is growing into just a single layer of the colon on the inner side, with ESD, it can be removed in one piece to allow pathologists to stage it, determining whether it is a curative resection or will need radiation, chemo, and surgery.
The first advanced procedure incorporated into the gastroenterologist arsenal was ERCP. Along with camera visualization of lesions in the esophagus, stomach, and small bowel, with ERCP, Liu can place stents or remove stones in the bile ducts. Previously, this required open surgery. Liu acknowledges that ERCP is a high-risk procedure used only for therapeutic purposes on patients who absolutely need it. These patients often present with jaundice, abnormal liver tests, and intermittent right upper quadrant pain despite gallbladder removal.
Pre-oral endoscopic myotomy (POEM), also pioneered in Japan, is a revolutionary endoscopic therapy for achalasia, a swallowing disorder. Liu had the privilege of learning this procedure from his mentor, Peter Draganov, MD, who trained with the Japanese physicians who perfected the procedure.
“POEM is a new procedure that falls under this new field of what we call third-space endoscopy. It’s basically where we enter the natural GI wall with our endoscope where we can tunnel with our camera and perform therapeutic procedures,” Liu explains. Previously, the only option was a laparoscopic Heller myotomy or a large balloon, which required an extremely healthy patient and often ruled out the older population. POEM is performed under general anesthesia and usually requires no more than an overnight hospital stay.
Achalasia is an incredibly challenging condition, with patients often suffering for 10 or even 20 years before being properly diagnosed and treated. According to Liu, “Before the POEM procedure, these patients are not able to eat or drink at all. They complain of chest pain regurgitation, have significant morbidity, and are afraid to go out to eat in public for fear of eating food and then having to run to the bathroom to throw it up. Sometimes these patients will have food that’s retained in their esophagus for even weeks. And then, after the procedure is over, they’re able to eat and drink normally.”
A third emerging area in the field is bar-iatric endoscopy, which involves endoscopic procedures to help combat obesity. Liu said, “We’re able to do endoscopic suturing, where we take our camera and suture within the GI tract to create a sleeve, basically sleeve gastroplasty.” UofL Health is in the early stages of incorporating bariatric endoscopy into its long list of procedures.
New Screening Guidelines
Naturally, one cannot discuss the field of gastroenterology without discussing colon cancer. The American Cancer Society lists colon cancer as the third leading cause of cancer-related deaths in men and in women. Statistically, one in 23 men and one in 25 women will be diagnosed within their lifetime. New recommendations dictate that individuals should begin scheduling colonoscopies at age 45.
“Colon cancer is one of those cancers that we can help prevent from forming. It often arises from polyps, and if it hasn’t invaded deep into the walls of the colon, we’re able to perform colonoscopy with snare removal and remove these polyps before they become cancer,” Liu states. “Early screening and doing colonoscopy early in patients when they first develop signs and symptoms is paramount.”
Several factors play into a person’s likelihood of developing colon cancer: age, obesity, smoking, high cholesterol, and a genetic component, such as familial adenomatous polyposis (FAP). Liu says, “It’s a really complex equation where genetics and environment are both involved, including age as well, too. So, it’s not as simple as one thing. And that’s why we do screening for everybody at age 45 and earlier with a family history or symptoms.”
As the field continues to move away from open surgery, Liu is looking forward to adopting new tools and new skills and offering his patients an even greater number of minimally invasive, safe, and effective procedures.