by Jill Clendening

Acute care surgeons at Vanderbilt University Medical Center are leading a two-year, multicenter observational study of a minimally invasive technique to control life-threatening blood loss by inserting a balloon inside the aorta to restrict blood flow below the heart.

Funded by a $6 million U.S. Army Medical Research and Development Command grant, the Partial REBOA Outcomes Multicenter Prospective Trial (PROMPT) will examine clinical outcomes when using a procedure called partial resuscitative endovascular balloon occlusion of the aorta (REBOA) to control hemorrhage and to better define the safest and most effective way to perform the procedure.

“We believe from our experience with the device that it clearly has benefits, but we want to fine-tune this procedure so we can provide the maximum benefit for the greatest number of patients,” said co-principal investigator Bradley Dennis, MD, associate professor of Surgery and medical director of VUMC’s Trauma Intensive Care Unit. “Doing this now, in a controlled fashion with a limited number of trauma centers, will help us standardize partial REBOA use and identify the best practices so we can then help spread that information to the rest of the country.”

Hemorrhagic shock, when severe blood loss leads to inadequate delivery of oxygen to the body’s cells, is a leading cause of death following a traumatic injury. And serious injuries to non-compressible areas of the body such as the torso and abdomen are a clinical challenge due to a lack of effective ways to control bleeding without causing significant harm to the body.

The first documented use of a balloon — a Foley catheter — placed inside the aorta to stem uncontrolled bleeding was during the Korean War in 1954. The idea gained adoption by civilian medical centers in 2017 when a REBOA device was approved by the Food and Drug Administration. VUMC trauma surgeons were trained and began using the devices that same year. To date, the technique has been used for approximately 150 trauma patients who met the Medical Center’s criteria for the procedure.

Endovascular hemorrhage control (EHC) devices and minimally invasive techniques such as REBOA are now in use at trauma centers throughout the world. The newest version of the device has the ability to allow partial blood flow to the body in a controlled manner. This is expected to reduce harm and give medical teams more time to surgically stop bleeding.

Six North American trauma centers that were early adopters of REBOA technology, including VUMC, are now using the partial REBOA and are joining the observational study being led by the Medical Center’s Acute Care Surgery team.

REBOA involves feeding a small catheter with a balloon into the femoral artery and upward to sit inside the aorta, the body’s largest artery originating from the heart’s left ventricle. A team trained on the procedure typically inserts the balloon in the Emergency Department before the patient is moved to an operating room or an interventional radiology procedural suite. The inflated balloon restricts blood flow below the aorta and stabilizes blood pressure, so the individual’s life is sustained while repairs are made, and the original source of bleeding is addressed.

At VUMC, REBOA has been used largely for blunt trauma injuries, most often the result of motor vehicle crashes. An example is a severe pelvic fracture where a high volume of blood can be lost rapidly. REBOA has also proven to be an invaluable tool in other circumstances in the operating room.

“If surgeons are doing a procedure with a high risk for hemorrhaging, we can put the catheter in and not inflate the balloon, which means that we’re not occluding the aorta at all,” said co-principal investigator Stephen Gondek, MD, MPH, assistant professor of Surgery. “But if something goes wrong, it takes three seconds to inflate it and temporarily stop the blood flow.

“A good example of this is placenta accreta, a high-risk, obstetric condition that people used to die from, even at very good medical centers like Vanderbilt. Now we can put the REBOA in and instead of having to remove the uterus as quickly as possible because a patient is bleeding uncontrollably, a trauma surgeon can quickly inflate the balloon. Then, the hemorrhaging is stopped, and the medical team has time to do what’s needed. We’ve been fortunate that we’ve only had to use the REBOA sparingly for those patients.”

While REBOA has proven effective in stemming blood loss, the reduction in blood flow — especially if that flow is halted for longer periods of time — can result in ischemia-reperfusion injuries or tissue damage that occurs when the blood supply returns to the body.

“The most common complication of REBOA is acute kidney injury or AKI,” said Dennis. “Up to 40% of people who survive hemorrhagic shock who received REBOA can have AKI, but while AKI is one of those problems we don’t necessarily look forward to, having that problem means the person lived. So, we accept that risk.”

Other potential complications include thrombosis or the formation of blood clots that can threaten the extremities and compartment syndrome where increased pressure within a muscle compartment causes pain and muscle and nerve damage. If the device is inserted improperly, it can rupture the artery.

PROMPT is supported by the Department of Defense Congressionally Directed Medical Research Program, grant number W81XWH-22-90015. In addition to VUMC, trauma centers participating in the study are OhioHealth Grant Medical Center, Grady Memorial Hospital, Tulane University and Louisiana State University (via University Medical Center), Denver Health and St. Michael’s Hospital in Toronto.