TAMPA — Dr. Murray Shames holds a flexible, lightweight tube as wide as two garden hoses pushed together in his office at Tampa General Hospital.

The polyester tube, and its thinner fastening branches with metal wiring, will be attached inside someone's aorta later this week to repair an aneurysm. It's a procedure Shames has done many times, and at least six times with this new tool, called an endograft stent.

It also has a much longer name: the Valiant Thoracoabdominal Stent Graft System, made by the medical device company Medtronic.

Shames, the division chief of vascular surgery at Tampa General and USF Health, is a lead researcher in early clinical testing by the U.S. Food and Drug Administration of the device, which is used to treat abdominal aortic aneurysms.

He and his growing team of vascular surgeons in Tampa are one of six medical institutions charged with implanting and collecting data on the device before it can advance to wider trials. But Shames already predicts that it is the future of treating the most risky aortic aneurysms, which are often fatal.

"Most stents are designed to match people's anatomy. The problem is that everyone's anatomy is different," said Dr. Patrick Kelly, a vascular surgeon with Sanford Health in South Dakota, who invented the device. "So this is not an anatomic design. It's more like how a plumber would plumb something. It runs through all the branches."

Abdominal aortic aneurysms occur on a weakened wall of the aorta, the major blood vessel that carries blood from the heart to the abdomen, pelvis and legs.

They develop without warning and grow larger over time. The bigger they get, the more dangerous they become, as the risk of rupture increases. The aneurysms most often look like a bubble bulging from the side of a blood vessel. If it bursts, a patient can bleed to death in minutes.

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Only 20 percent of patients with a ruptured abdominal aortic aneurysm survive, according to the American Heart Association. The Centers for Disease Control and Prevention reports that these kinds of aneurysms caused 9,863 deaths in 2014 and contributed to more than 17,000 deaths in 2009. About 15,000 new cases are diagnosed every year.

Less than half of patients who suffer an abdominal aortic aneurysm rupture make it to the hospital in time, Shames said.

"Many of the patients I see had no idea they had an aneurysm before they start experiencing complications," he said. "Medicare covers a one-time free aortic aneurysm screening, but I don't think many people know enough about it to ask for the test."

Men make up about two-thirds of aortic aneurysm patients in the U.S. Those who smoke or use tobacco are even more at risk, by three to five times. Other risk factors include obesity, high blood pressure, high cholesterol, atherosclerosis or hardening of the arteries, some genetic conditions such as Marfan Syndrome, and family history.

The endovascular surgery is considered less invasive, as surgeons make an incision in the femoral artery near the groin and pass the device into the aneurysm while using an x-ray monitor to guide them. Once threaded into the aorta in a series of steps, the device hugs the walls of the vessel, providing a new passageway for blood in the abdomen's largest artery.

Much more risky is open surgery, requiring an incision in the abdomen.

"Many patients come to us in their 70s and 80s with other health issues, which puts them at greater risk," Shames said. "This surgery is less invasive, and has the chance to give these most at-risk patients better outcomes."

Prior to using the new device, Shames said he and his team were developing their own "off label" one. Among themselves, they called it "the octopus method."

So far, Shames has performed six surgeries with the new device. He said all of his patients are recovering, but there are some side effects. For example, the risk of paralysis is great, especially when working on an abdominal aortic aneurysm near the kidneys, where blood vessels can branch into many more vessels, and can be small and difficult to reach. More research is needed to understand how the technique will aid patients in the long run, but Shames said he hopes it will have a significant impact.

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Shames and his fairly new division of vascular surgeons have participated in several trials in the past, including a newer graft called Z-Fen, short for the Zenith Fenestrated AAA Endovascular Graft, developed for patients also with an aneurysm near the kidney arteries. The new device developed by Kelly is used to treat even more complex cases.

Shames consults with surgeons from the other data-collecting institutions: New York University, Vanderbilt University, Johns Hopkins University and the Christ Hospital in Cincinnati, in addition to Kelly's team in South Dakota.

"Most surgeons refer patients with these kinds of aneurysms to specialists like us, because they are so risky," Shames said. "People don't want to operate, given the high risk."

So far, Kelly said, the team has not reported many problems in patients, which bodes well for the trial to move to the next level and reach more patients in need.

"Everything about this disease is risk-management," said Kelly, who has more than 160 patents to his name. "It has horrific outcomes, and hopefully we can start lowering that bar."

Times correspondent Irene Maher contributed to this report. Contact Justine Griffin at jgriffin@tampabay.com or (727) 893-8467. Follow @SunBizGriffin.