In her office at Henry Ford Hospital, cardiologist Dee Dee Wang has more than 100 3-D models of hearts on a bookshelf. Each heart is custom-made for patients based on CT scans of their hearts. She calls them her clinical heart library.
"Our patients are too frail and not candidates for open heart surgery, and their remaining option is getting readmitted to the hospital, or hospice. They have less 6 months to live, so they are very sick and have run out of options," said Wang, who is head of structural imaging and medical director of 3-D printing at Henry Ford Innovation Institute.
Nearly five years ago, cardiologist William O'Neill, M.D., Henry Ford's medical director of the Center for Structural Heart Disease, began doing transcatheter mitral valve replacement procedures using medical 3-D procedures under an FDA humanitarian exemption. The mitral valve connects the left upper (atrium) and lower (ventricle) chambers of the heart.
However, this heart procedure is one of the most technically challenging because the mitral valve is one of the most complex structures in the heart. Incorrect valve sizing can cause the valve to embolize, creating blockages. An embolism could block blood flow to the rest of the body and cause harm.
Using 3-D imaging, planning and printing, O'Neill and fellow cardiologist Adam Greenbaum, M.D., created new techniques using a wire guided up through the femoral vein in the leg to the heart to open more blood flow to the rest of the body. This allows safe implantation of these valves into patients and could potentially help thousands of patients, Wang said.
More than 13 percent of patients over age 75, or approximately 5 million people, have some degree of aortic or mitral valve disease. So far, Henry Ford has successfully performed more than 200 of the procedures, including placing a valve in the mitral position more than 50 times, the hospital said. The FDA gave approval for the mitral valve in valve implantation last fall.
"Dr. O'Neill is working on a problem where the patient has no or low blood flow. We can't do surgery in those instances," Wang said. "For many patients, we think we have fixed the problem and now these patients are candidates for mitral valve replacement."
3-D printing is also helping cardiologists improve a more common procedure called the "left atrial appendage closure," Wang said. This procedure is for patients with irregular heartbeat conditions, called atrial fibrillation, who are not able to take blood thinners. The danger of a clogged atrial appendage pouch is that a blood clot could form, break away and cause a fatal stroke. Henry Ford has conducted more than 1,000 of the atrial procedures.
Two years ago, the FDA approved a device called the Watchman for use in this type of procedure. But imaging planning for the procedure was lacking.
By printing out the exact replica of the heart, Wang said, cardiologists could get a better view of the blockage and devise a better surgery plan.
"Before, there was a 16 percent complication rate," said Wang. "By innovating 3-D imaging and 3-D printing customized case plans for our patients, we demonstrated that in our first 100 patients we had zero complications."
Wang said the use of the 3-D model for atrial appendage procedures "helps us to choose the right size of the catheter" inserted into the patient's body to place mesh devices. She added that the 3-D model also gives doctors a better idea of how large the Watchman self-expanding device needs to be to open the atrial appendage.
Wang said manufacturers make five sizes, but many more are needed because each patient's heart, valves and appendages are different sizes.
"Before, you had to guess the right sizes," Wang said. "Now we have a better idea what ones to use." Data shows before 3-D was used, doctors used an average of 1.8 devices per patient; that number has dropped to 1.2, she said.
For the left atrial appendage Watchman procedure, Wang said the use of 3-D printing also cut surgery time to about 45 minutes from 80 minutes, reducing costs and improving outcomes.
Medical 3-D printing was the subject of jokes five or six years ago in some circles of medicine. Now, Wang said, 3-D has proven itself, because lives have been saved.
"People can't blow it off now. In the next 10 years, all hospitals will have in-house printers and all patients will have access to them," said Wang, adding that the future is limitless for 3-D applications in health care. "Bench research 10 to 15 years down the road will enable transplants and see early stem cells for organs."
Like many hospitals, payment for 3-D printing is a challenge. Henry Ford funds its 3-D program through Ford Motor Foundation grants.
"We are early adopters. We get phone calls from physicians in other hospitals in the U.S. and in other countries, France and Germany," Wang said. "We get questions how we do it and get lots of referrals — they fly in — if they can't do it locally."