Surgeons handle a human acellular vessel during an operation. (Humacyte Inc.)
Each Memorial Day, I’m especially mindful of the brave men and women I’ve seen make the ultimate sacrifice in defense of our country. Over the course of a medical career that’s taken me from the streets of Baghdad to the Helmand desert in Afghanistan to the ongoing conflict in Ukraine, I’ve laid eyes on some of the very worst battlefield injuries imaginable. Far too many front-line fighters have had their lives cut short, or forever damaged, as a result of the devastating wounds they suffered defending their country.
It’s never easy. It goes without saying that battlefield wounds are devastating; the human body is not designed to withstand the impact of high-powered ammunition. Combined with the fact that these wounds are highly prone to infection — due mainly to the dirt and fragments that can contaminate wounds — the physicians who treat these injuries are often presented with the most challenging cases of their lives.
As a surgeon, it’s critical that you know what you’re doing, and are capable of doing it quickly enough to save the patient who’s on your operating table. The same kinds of injuries that we treated in Iraq and Afghanistan – blasts, gunshot wounds, and crush and burn injuries – are now flooding emergency rooms in Ukraine.
Battlefield medicine often drives innovation — anesthesia was first put into wide use during the Civil War, X-rays in World War I, blood banks in World War II, and one-handed tourniquets in Afghanistan.
We may stand at a similar moment now for the treatment of damaged blood vessels that is necessary to save life and limb on the battlefield. In these cases, the gold standard for repairing blood vessels and restoring circulation to mangled limbs is what’s known as a saphenous vein – a blood vessel found in your legs that can be removed by a trained surgeon and implanted into another injured limb in order to support the continued supply of blood and oxygen and prevent the need for amputation. A successful operation can make the difference between a patient dying on the operating table or returning home with all of their arms and legs intact.
The reality, however, is that harvesting a saphenous vein is challenging. It takes time and skill. Many surgeons on the front lines of a war zone are confronted with dirty wounds prone to infection and very little time to salvage a limb that has been deprived of its blood supply. This must be accomplished in less than 4-to-6 hours.
When a bypass fails, it can be devastating for the patient, leading to a sudden onset of problems that threaten the patient’s well-being. This is more common when the saphenous veins cannot be used to treat injuries caused by improvised explosive devices, as has been the experience in Iraq and Afghanistan, where harvesting a vein from the patient is often difficult or impossible.
While our ability to treat traumatic injuries has improved greatly over the years, there has long been a need for an off-the-shelf product that surgeons can use quickly when the saphenous vein is not available in order to save limbs and return our service members to productive lives after being injured in combat.
Development of the Human Acellular Vessel, or HAV, starts by taking living cells from a human blood vessel and placing them onto a tube-shaped frame. These vascular cells are kept alive in an organ chamber, growing around the tube-shaped lattice. Over time, the lattice that was used to seed the original vascular cells dissolves, and scientists remove the original cells so the new vessel doesn’t cause an immune response when it’s implanted. What is left is a solid, tubular structure made of human vascular material that looks and acts like a blood vessel — thus, the bio-engineered and newly-grown blood vessel, or HAV. (Illustration by Sofia Echelmeyer, Uniformed Services University)
That’s why it’s so exciting that a breakthrough product — Humacyte Human Acellular Vessel — is now being used to treat the wounded in Ukraine. The HAV, which is a bioengineered tissue that regrows with a patient’s own cells to create a living artery, represents an incredible step forward for the future of regenerative medicine both in foreign combat theaters and for treating traumatic injuries here at home.
Because it regrows with a patient’s own cells to become living tissue, the HAV is more resistant to infection than the other treatment options we have today. Being a universally implantable product that is ready off-the-shelf and can be stored for up to 18 months, the Human Acellular Vessel may be a good option when using saphenous vein is not possible.
Humacyte began a humanitarian effort in Ukraine shortly after the Russian invasion to provide HAVs to front-line hospitals to treat war-wounded patients. Beginning 11 months ago, when the first shipments arrived, the HAV has been put into use at five hospitals throughout Ukraine where injured soldiers are being treated. This is an exciting new bioengineering technology for the treatment of vascular injuries that, in previous wars, may have resulted in amputation or worse.
With over a decade of clinical research experience, the HAV has established a promising record of dependability. If proven, this could even mean offering new options for patients who suffer from other conditions like end-stage renal disease and peripheral artery disease.
This Memorial Day there is reason to hope that we are on the verge of a major breakthrough in the treatment of battlefield wounds. The HAV has offered a new option to Ukraine’s war-wounded, and there is no telling what this technology could mean for the future of vascular regenerative medicine.
Dr. Charles J. Fox is an associate professor of surgery at the University of Maryland Medical Center, a retired U.S. Army lieutenant colonel, and the former program director for vascular surgery training at Walter Reed Army Medical Center, Washington, D.C. He is not paid by or affiliated with the company that manufactures the HAV.
