© 2023 Texas Public Radio
Real. Reliable. Texas Public Radio.
Play Live Radio
Next Up:
Available On Air Stations

Cutting Down On Dye: Safer Heart Procedures For Kidney Patients

South Texas has more than its share of kidney disease. A high incidence of diabetes puts people at risk of renal failure. Heart procedures can threaten fragile kidney function, too. A new device is making heart repair safer for kidney patients.


Heart symptoms have sent Steven Tshappatt to University Hospital for a cardiac catheterization.

"I’ve been having chest pains and shortness of breath. It’s hard being a diabetic," Tshappatt said.

Credit Wendy Rigby / Texas Public Radio
Texas Public Radio
Steven Tshappatt, 33, prepares for a heart procedure at University Hospital. Dr. Anand Prasad (right) is an interventional cardiologist.


He is only 33 years old, but Tshappatt was diagnosed with diabetes at age 22. He’s paid the price of developing the disease so early in life. 

"I’ve had to have amputations," he explained. "I’ve had to have eye surgeries."

When patients like Tshappatt need an angiogram, a stent placement or a balloon angioplasty, physicians have to inject dye to get the imaging they need -- the roadmap, if you will, for the procedure. For people with normal kidneys, that iodine contrast is no big deal. We’ll flush it out of our bodies quickly.

For Tshappatt, with only 30 percent kidney function, the risk is much greater explains Anand Prasad, MD, an interventional cardiologist with UT Health San Antonio.

Credit Wendy Rigby / Texas Public Radio
Texas Public Radio
The cardiac catheterization lab at University Hospital is where doctors are using the Dye-Vert Plus.


"But in patients with impaired kidney function, the dye hangs around and it’s actually toxic to kidneys," Prasad explained.

Prasad said patients know this and they’re afraid. "They don’t ask about dying. They don’t ask about heart attacks," he said. "They say ‘I do not want to end up on dialysis.’ That’s their number one fear."

New technology is helping solve an old problem: how to control and  monitor the amount of contrast dye being used throughout the procedure. Right now, it’s inexact.

San Antonio's University Hospital is one of the first hospitals to use a device called Dye-Vert Plus. Bluetooth technology imbedded in the syringe uses wireless transmission to track exactly how much dye is used for each image. It’s added up in real time on a screen physicians monitor. Based on a patient’s blood pressure, age, gender, weight, and their condition, the machine can alert doctors when they’ve maxed out on dye.

Credit Wendy Rigby / Texas Public Radio
Texas Public Radio
The Dye-Vert Plus keeps track of the amount of dye interventional cardiologists are using in real time, displaying it on a screen.

"And so we know exactly, milliliter by milliliter, how much contrast dye we are giving patients," Prasad explained. "And that’s a big advance for the first time in the cath lab. It’s a big advance in the way we do angiograms."

Tests of the new device show it can reduce the amount of dye used in heart procedures on kidney patients by as much as 40 percent. That kind of precision may keep some patients from an agonizing choice of repairing their hearts or preserving their kidneys.


Wendy Rigby is a San Antonio native who has worked as a journalist for more than 25 years. She spent two decades at KENS-TV covering health and medical news. Now, she brings her considerable background, experience and passion to Texas Public Radio.