Understanding Arterial Occlusion System Use for Safer Postpartum Hemorrhage Treatment

An evolution of resuscitative, endovascular balloon occlusion of the aorta (REBOA) technology used to manage bleeding in trauma patients could offer much-needed quicker and safer bleeding control in some with postpartum hemorrhage.

The Control of Bleeding, Resuscitation, Arterial Occlusion System (COBRA-OS) system by London, Ontario-based Front Line Medical Technologies is the smallest life-saving REBOA device available with FDA clearance and Health Canada approval, according to a company press release. 

COBRA-OS’s FDA indication is for temporary occlusion of the aorta in patients who are hemorrhaging, or temporary occlusion of large blood vessels. That includes trauma, as well as postpartum hemorrhage.

Front Line Medical Technologies is focused on postpartum use because it’s a growing and largely unmet need, according to Adam Power, MD, MPhil, Front Line Medical Technologies chief medical officer, COBRA-OS cofounder and coinventor, and a practicing vascular surgeon.

“By using these devices — our device — people are getting potentially better results that are starting to be seen in the literature. Those results [and the outcomes we’re looking for in ongoing clinical trials] are less blood transfusions to mothers, less unplanned hysterectomy rates and ultimately less death,” Power said.

The toll

Postpartum hemorrhage is hard to predict, is associated with significant maternal morbidity and is the leading cause of maternal mortality worldwide, according to a paper published in the American Journal of Obstetrics and Gynecology.

Postpartum hemorrhage impacts not only mothers in the developing world, but also in the United States, where rates of postpartum hemorrhage requiring blood transfusions for caesarean deliveries more than doubled from 2001 through 2002 to 2011 through 2012, from 2.0 to 4.8. The increase in postpartum hemorrhage came with rises in rates of hysterectomy, embolization, and uterine tamponade, according to a paper in Blood Transfusion.

Power said this relates to a pregnancy issue that causes significant bleeding, placenta accreta, or when the placenta grows into the uterine wall.

Additionally, delivery can result in the placenta tearing and torrential bleeding that can’t be stopped. “You have to do an emergency hysterectomy to stop the bleeding and sometimes you lose the mother in the process,” he said.

That’s where the COBRA-OS comes in, according to Power.

However, it’s not the only technology designed to stop postpartum bleeding. One is an intrauterine vacuum-induced hemorrhage-control device called the JADA system, from women’s health company Organon, with which doctors aim to stop bleeding within the uterine cavity.

“There can be ongoing bleeding, so trying to turn off the tap a little higher up is sometimes what’s necessary,” Power told MD+DI. “If you can go into the aorta and clamp the aorta higher up, it really does turn off the tap to the lower body and allows you give the blood back to the woman (fill up the tank) before releasing the clamp.”

Overcoming design challenges

Clamping the aorta is an invasive procedure — one that Power does often as a vascular surgeon. But vascular surgeons aren’t always available to assist during postpartum hemorrhaging, so Power and colleagues figured out how to accomplish much the same less invasively.

COBRA-OS is, in essence, a balloon that reaches the aorta through the femoral artery in the groin. Once they inflate the balloon in the aorta, clinicians stop the bleeding internally — versus an external clamp.

“You can usually do a full occlusion in about 30 minutes,” Power said.  “If they’re doing a c-section, they inflate the balloon if there’s bleeding, and deflate it if they’ve got control. It’s sort of a dynamic process.”

COBRA-OS is different than traditional 7 French scale (Fr) sheath REBOA devices used in trauma cases, approved by the FDA, Health Canada and with a CE Mark in Europe, he said.

“We use this French system in the profile of endovascular devices, which is basically the diameter,” he said. “A cardiology procedure would be done with a 4 or 5 French device. That would go through the wrist. As you get larger and larger devices, they go up in French size. What that means is that there is less room in the arteries.”

A 7 Fr sheath is a problem for women’s small arteries and can cut off blood flow to a limb before it’s inflated, according to Power. In turn, making the COBRA-OS a 4 Fr device helps to ensure perfusion without occlusion until the device activates.

COBRA-OS also saves time, according to Power, which can be a lifesaver for patients. “Normally, you don’t start with a 7 Fr sheath. You actually have to place a smaller sheath first and then up the size of the sheath. We save that exchange from a smaller to a larger sheath,” he said.

Real-world practice

Hospitals are using COBRA-OS and collecting data on its efficacy and safety. But to say the device decreases complications of treating postpartum hemorrhage is theoretical until more data comes out, Power said.

Front Line Medical Technologies has experienced hurdles in deploying COBRA-OS. One problem is the need to find the right patients who will benefit.

The other is a challenge for which Power uses a “Tylenol analogy.”

“If you give too much Tylenol to someone, you’ll kill them,” he said. “If you occlude someone’s aorta for too long, you will kill them. That’s what we over the past 10 years have learned is to minimize occlusion times, do intermittent occlusion, partial occlusion. That is showing much better results than inflating the balloon, leaving it up for an hour and having patients do badly. That has soured some people on the technology but we’re actively working to show that there are definitely a group of patients that benefit and minimizing occlusion times is essential.”

Last year, Front Line Medical Technologies shared its first real-world postpartum hemorrhage data using the COBRA-OS, which was presented at the Pan-American Society for the Placenta Accreta Spectrum 5th Annual Meeting. Texas Children's Hospital, Baylor College of Medicine, in Houston, Texas, and Atrium Health, Wake Forest Baptist Medical Centre, have adopted the COBRA-OS for many high-risk placenta accreta patients, according to a company press release.

"This real-world, non-industry sponsored data showed significant reductions in blood loss and transfusion requirements in one study and was helpful when used in a selective hemorrhage control strategy in the other," co-founder and CEO Asha Parekh, PhD, said in the release.

One of the studies demonstrated COBRA-OS’ utility for intermittent and partial REBOA applications, according to Parekh.

What’s next?

Currently, trauma centers in the US and Canada, along with the US military, use the COBRA-OS. The military uses it to help with noncompressible torso hemorrhage from trauma.

In addition to postpartum hemorrhage, Power and Parekh want to pursue studies looking at COBRA-OS’ use in nontraumatic cardiac arrest. Studies are just beginning to suggest that occluding the aorta during CPR is more effective at resuscitating patients than CPR alone, according to Power.

Should these trials show better rates of resuscitation and neurologic recovery with aortic occlusion and CPR for nontraumatic cardiac arrest, Power and Parekh plan to move forward with their technology.

“I’d love to see our device used for cardiac arrest prehospital in Europe,” he said. “Once we prove prehospital in Europe, I think there may be more appetite in North America for developing some of these protocols.”