Hydroxyethyl Starch: Optimal Injectate for ESD Commonly Available in the West

Of the commonly available injection solutions used, hydroxyethyl starch is the best fluid to use as injectate during endoscopic submucosal dissection (ESD) in the United States.

Findings of a recent study show that hydroxyethyl starch (0.9% normal saline solution) offers, on average, 30 percent faster procedure time at 26 percent greater ease than the next-best option, hydroxypropyl methylcellulose.

“The injection fluid used in ESD is important to both performance and safety of the procedure because it allows the endoscopist to separate the lesion from the muscular wall of the GI tract to allow a safe plane of dissection,” says Amit Bhatt, MD, a Cleveland Clinic gastroenterologist who designed the study and senior author on a presentation about the findings at Digestive Disease Week 2017.

The study compared seven commonly used injectates for elevation of tumors (in millimeters) from the time of injection over a 20-minute interval in an ex-vivo porcine stomach.

Overall, hyaluronic acid (HA) was the highest-performing solution, offering superior elevation and durability. However, Dr. Bhatt and his collaborators ruled it out as a viable recommendation as an injectate in the West because of its unavailability and high cost.

In order of overall performance among the remaining six solutions, hydroxyethyl starch took top scores in both elevation and durability, followed by hydroxypropyl methylcellulose (HPMC), D5-water (5% dextrose), D5-normal saline (5% dextrose), hypertonic saline (3% NaCl) and normal saline (0.9% NaCl).

New procedure, minimal data

Dr. Bhatt, Neil Mehta, MD, and his collaborators decided to study ESD fluid performance not only because of their central importance to procedural success, but also because much of the current data regarding submucosal injection fluids come from Japan, where ESD was developed and where hyaluronic acid is available for significantly less.

“ESD was pioneered and refined in Japan,” says Dr. Bhatt. “Now that interest in ESD is growing in the United States and elsewhere, our aim is to identify optimal tools and fluids that will maximize success for our patients.”

ESD is an advanced endoscopic procedure performed in the esophagus, stomach or colon. Fluid is injected into the submucosal layer to isolate the tumor from the gastrointestinal wall. Endosurgical knives are used to dissect the submucosa and to release the lesion as a single entity.

Benefits include en-bloc resection, ability to retain full organ function, decreased mortality and faster recovery times, to name a few.

Because of these improvements, Western gastroenterologists have taken an interest in ESD but have lacked sufficient evidence on the optimal fluids and tools to utilize this procedure.

“Because hyaluronic acid is difficult to obtain in the U.S. and is prohibitively expensive in most instances, ESD specialists have been using a variety of unstudied fluids,” says Dr. Bhatt. “We hope this type of study will make ESD easier for Western endoscopists to perform by providing them an easily obtainable cost-effective injection fluid that outperformed its competitors.”

To the test

In order to settle the fluids debate, Dr. Bhatt, Dr. Mehta and the study collaborators went a step beyond laboratory models, creating a porcine simulation in which an ESD specialist performed the procedure using one of the two top-performing options.

The fluids were randomized, and the endoscopist was blinded to which injectate was being administered. As in the laboratory modeling, hydroxyethyl starch resulted in faster and easier procedures.