The middle-aged man on the gurney at Erlanger hospital is unconscious.
His body is covered with a sheet so only his face is showing, but he has obviously been in an accident. Blood is visible from the scrapes and scars on his cheeks.
He is bleeding internally after flipping his car end-over-end several times and Dr. Blaise Baxter is trying to figure out how to stop the bleeding.
To Baxter's left, a large video screen, perhaps 2 feet by 18 inches, displays a black-and-white image of the man's abdomen. Dark lines show the arteries and veins that move blood throughout his body, like a map of the Tennessee River and its tributaries.
With a scalpel, Baxter makes a small incision on the man's groin, in his femoral artery, and inserts a tiny wire, flexible but strong.
Slowly, carefully, peering intently at the screen to see the progress of the wire, Baxter pushes it deeper into the man's body, down a major artery then into a tributary. He twists it left into a side channel, right into blood vessel, and stops at the place where the splotch of gray on the screen indicates the leak is located.
Then he takes out a tiny catheter, a hollow tube made of plastic and metal only slightly larger than the wire, and pushes it down into the artery, sliding over the wire as a guide. On the tip of the catheter is a tiny plug and he maneuvers it into place, right THERE, where the blood seems to be seeping into the body.
He pulls out the wire and then with a final twist pushes the tip of his tube against the narrow artery walls. As he withdraws the catheter, the plug remains behind, blocking the blood from leaking out. The dark lines on the monitor turn gray and Baxter shakes his head affirmatively. "That seems to have done it," he said.
What Baxter, an interventional radiologist, is doing is not surgery - he isn't trained as a surgeon.
It's called a "procedure," but the better analogy is to a plumber who can plug leaks and clear clogs in the body's pipes - its thousands of large and small blood vessels.
Baxter can thread a catheter up the leg artery, through the aorta, the main artery to the heart, and up into the brain, right to the spot where a clot is blocking the flow of blood and threatening to cause a stroke. With a twist of the catheter he can ensnare the clot and then pull it all the way out of the brain.
What makes it all possible are imaging tools that have gotten steadily better over the past 20 years, just as personal computers have evolved from clunky desktop machines displaying green text to the latest smartphones that can record your world in high-definition video.
"Now with the advances in technology, we can get better image resolution, very, very detailed," Baxter said in a recent interview. "We need to see tiny devices - stents and such that we're putting in vessels - and we can see way better."
The incoming president of the 800-member Society of NeuroInterventional Surgeons, Baxter specializes in neurological procedures. Besides his clot-grabber, he also has a "clot-sucker" tool that operates just like a vacuum cleaner to clear a blood vessel.
In addition to being able to see better, Baxter and other doctors like him also have better wires and tubes to work with. Wires and catheters are stronger, more flexible and smaller, allowing them to go into tinier blood vessels.
A key tool is a new alloy, nitinol, that can change its shape depending on how warm it is. At body temperature, the metal is shaped into something useful, such as a stent - a sheath of metal mesh that can be inserted into a blood vessel to keep it open. The cooled stent can be reshaped, shrinking or straightening, perhaps, so it can be inserted through a small catheter. Once in place, the stent warms to body temperature and expands to its original shape, pushing open the walls of the blood vessel.
"Metal has leapfrogged the field," Baxter said. "It's a pretty high-end engineering feat."
But doctors who navigate the body's blood vessels can do more than just grab clots or push in expandable stents. With the catheter is in the right place, a tiny camera can be inserted so the doctor can see the inside of the blood vessel. Or a chemical can be injected through the tube into the blood vessels that will show up in an X-ray, giving the doctor a more detailed view of where blood is flowing correctly and where it is blocked or leaking.
While Baxter roots around in the brain, Dr. Chris LeSar at the Vascular Institute of Chattanooga is probing the blood vessels in the rest of the body below the head. LeSar is a vascular surgeon who specializes in cleaning out the arteries and veins in the arms, neck, feet and legs.
When he first meets them, many of his patients have extreme swelling in their lower legs and feet and are having trouble walking. In the past, many would be facing amputation, or perhaps a bypass where a doctor would take a vein from the leg and connect it to an artery below and above the blocked blood vessel.
"The biggest issue was when we did major vascular surgery, we knew that 5 to 25 percent of patients would have a complication," LeSar said. "Now when we are operating from the inside of the arteries, complication rates are extremely small."
Now, LeSar can insert a catheter into blocked vessels and clear them in his office without general anesthesia.
In his consultations with patients, he plays up the plumbing analogy, referring to himself as a plumber using a rotary tool to clear clogged veins and arteries.
Baxter is more likely to be battling blood clots, while LeSar's usual enemy is plaque building up in the blood vessels, what was once called "hardening" of the arteries.
"There are all of the different chemicals - calcium, iron and different things that will build up in different parts of the body," he said.
But his tools are the same as Baxter's - stents to force open arteries or to deliver drugs or marker chemicals that will show up in an X-ray, or tools to burrow through the plaque or a clot.
Unlike Baxter's patients, who often show up in the emergency room after having a stroke, LeSar's sometimes wait too late before seeking assistance, he said.
"People don't want to know what to do if they have a major problem with circulation," he said. "If they have a major stroke symptom, such as chest pain, they will go to the hospital. But if they are having a leg attack - severe pain or a sore that doesn't heal or a toe that returns black - they will wait too long and will get to a point where they have destroyed so much tissue that they will lose a leg. If I can find that patient sooner, I can fix the problem and can save their leg."
LeSar and his staff of 30 just moved into a large new facility off Shallowford Road.
Sadly, he said, neither he nor Baxter have any worries about a lack of patients.
"Smoking is endemic here, people start in their early years," he said. The chemicals in the smoke go from the lungs to the bloodstream to the heart and then straight out again to the blood vessels, where they degrade the layer of cells in the blood vessels that transfer vital chemicals to the body.
"We always knew [smoking] caused lung damage," LeSar said. "But it causes damage to the heart and arteries and causes PAD - peripheral artery disease. When somebody has PAD, they have a higher chance of dying from stroke and heart attack."
And poor diet and obesity and diabetes are "rampant" in the Southeast, he said.
While he is pessimistic about the chances the problems will decline in the near future, he is hopeful that more people can now be treated.
"People have to pay attention to their symptoms," LeSar said. "If they are having pain when they walk, that is not normal. If they are developing a weakness or having falling spells when they shouldn't, that is a sign of low blood flow. Fifteen percent of Americans have PAD. But 15 percent of Americans are not diagnosed and treated properly for PAD."
"If we can do that as society, we can prevent many heart attacks and keep people alive longer," he said.
Contact staff writer Steve Johnson at 423-757-6673, firstname.lastname@example.org, on Twitter @stevejohnsonTFP, and on Facebook, www.facebook.com/noogahealth.