Dr. Mayer Katz and his surgical team at Beebe Medical Center and Delaware Bay Surgical Service installed the first wireless pressure sensor in Delaware – to monitor a thoracic aneurysm – for patient Christopher Paxson of Milford.

An aneurysm is a ballooning of the aorta, the main artery that carries blood from the heart to all parts of the body. As the aneurysm grows, the chances for it to rupture increase, and a ruptured aneurysm is usually fatal. Aneurysms can be hereditary or caused by factors such as smoking, heart disease, high blood pressure and a high-fat diet.

“The chance of an aneurysm rupturing increases quite a bit when it’s more than five centimeters,” Katz said. “Size is very important. As size increases, the chance of rupture or death increases quite a bit.”

Patients can live with aneurysms and not know it; the only way to know for sure is through a computerized tomography (CT) scan, magnetic resonance imaging (MRI) test or an angiogram.

Paxson said he didn’t know he had the aneurysm. “We found it by accident, actually,” he said. “I had chest pains, and they said I had pulled a muscle. They just did it with a CAT [computerized axial tomography] scan. They said it was about time to get it [the surgery] done; it [the aneurysm] was getting big and they wanted to get it taken care of.”

When symptoms do occur, patients experience pain in the chest or back, shoulders, neck and abdomen.

Aneurysms come in one of two forms: an abdominal aortic aneurysm, which takes place in a person’s midsection; or a thoracic aneurysm, which hits closer to the heart.

Treating aneurysms has been a gradual evolution for doctors. The latest and greatest in medical technology for treatment is a stent graft. The graft is made of a plasticlike material. Its scientific name is expanded polytetrafluoroethylene. It is a tube-shaped piece that is inserted into the patient by way of the patient’s artery, via an endovascular surgical procedure. One of the advantages to an endovascular procedure, Katz said, is that recovery is much faster. The endovascular procedure is an improved and less invasive procedure than an open procedure in which the patient’s chest is cut open.

Procedure less invasive

In the endovascular procedure, small incisions are made near the patient’s groin. A catheter is then inserted in the leg artery and guided up into the chest. Katz said the graft is in a capsule form before it enters the body. Using an image intensifier, doctors can monitor where the catheter is placed.

Once the graft is positioned across the aneurysm, it is then released. The expanding graft blows up like a parachute when the cord is pulled. The graft self-expands to the diameter of the aorta and seals off the aneurysm. For a thoracic aneurysm, the graft expands from the center out.

Katz said his team, which has done 150 of these procedures since 2000, has a zero mortality rate.

What made Paxson’s procedure different is that the team installed a pressure sensor, made by CardioMEMS. The sensor is installed during the same procedure as the stent graft.

“It’s like a tuning fork. And we tune it to the arterial pressure. We can measure the pressure before and after [the procedure],” Katz said.

To monitor if the graft is leaking, Katz uses a remote device that looks like a plastic tennis racket. Katz said the sensor has been used on more than 50 local patients for abdominal aneurysms, but it had not been used for a thoracic aneurysm.

Thoracic grafts have been used at hospitals in Wilmington, Katz said, but Paxson is the first patient to use the sensor.

He said thoracic procedures present a much different challenge because surgeons must be wary of damaging the patient’s spinal cord. “The spinal cord depends on circulation coming from this area of the chest,” he said. “We always have to provide protection to the spinal cord.”

Katz said aneurysm procedures are truly a team effort. “It’s not just the team in the operating room. To do these, we really have to have a team concept. That is, we have an interventional radiology team, a vascular team and then a post-op nursing team. It seems very complicated, but here at the hospital, we are prepared for this,” he said.

A fast recovery

Going into the procedure, Katz said of Paxson, 47, “He does have some problems. He’s a bit on the heavy side. He’s hyperlipidemic [excessive lipids in the blood]. He’s a smoker.”

The size of the graft is determined by measuring a CT scan of the aneurysm via a computer program. At a quick glance, the graft looks like an oversize tooth.

“We want to oversize it so it will fit in there snugly,” Katz said.

Paxson was released from the hospital after a two-night stay.

“We operated on a Monday. On Tuesday we took out the spinal fluid drain and he just stayed in bed for a while, because we didn’t want any spinal fluid leakage. He went home on Wednesday,” Katz said.

Three weeks after his procedure, Paxson said, “I’ve actually felt really good. I’ve got a little bit of an issue with my legs because they’re so weak from the operation, but as soon as I get moving a little bit, I’m good to go. I actually feel I could go back to work now, but they won’t let me.”

Paxson said the procedure took five and a half hours. He said the sensor hasn’t been used yet, although he said he’s scheduled to go back to the doctor’s office. “I’m up and about. I can walk; I just can’t go overboard,” he said.

He said he was grateful to have had the procedure done when he did. “I felt like I was a walking time bomb,” Paxson said. “Every time I’d pick up something, I’d wonder, is this it? I feel great right now.”