Last year, while on vacation, RG Carver was using a trimmer to pull some weeds in his yard when he stepped into a cactus and stuck some needles into his leg. After a few days, his legs started to swell.
He traveled from his home in Double Horn near Spicewood to Baylor Scott & White Hospital in Marble Falls.
There they discovered that his heartbeat was speeding up. He had an ECG done on his heart for the first time. It was not at all the cactus that caused the leg swelling. It was his heart.
Carver spent five days in the hospital draining the fluid from his heart and the rest of his body.
Last January he underwent a procedure to get his heart back in the right rhythm. And he was on medication to regulate his heart, but he needed regular checkups, which meant he had to go to Marble Falls every few days to check in with his cardiologist, Dr. Justin Coyle.
Then Coyle recommended that Carver get a CardioMEMS. The device from Abbott, which has based part of its cardiac device business in Austin, measures pulmonary artery pressure in people with chronic heart failure. It is the size of a paperclip and is inserted through a catheter from the femoral vein in the leg to the pulmonary artery.
The procedure takes about 45 minutes. Patients cannot feel the MEMS in their body. Usually they may have pain in their groin where the catheter went in for a few days.
Until February, CardioMEMS was only approved for people with chronic heart failure who are hospitalized for it and experience symptoms such as shortness of breath when moving but not when sitting. Those patients have chronic heart failure class III.
After a survey of 1,000 people who didn’t meet those criteria, who either had never been hospitalized, had less severe symptoms, or had worse symptoms, the U.S. Food and Drug Administration expanded the use of the CardioMEMS to the less severe patients , Class II, and people with elevated levels of natriuretic peptides, indicating their heart disease is getting worse.
MEMS stands for micro-electro-mechanical system. Once the device is in place, that person rests once a day on a mat that picks up radio signals from an antenna in the CardioMEMS. Using a handheld device, the person then sends the pressure readings to the doctor.
The patient only needs to ensure that there is no interference between the MEMS and the transmitter. Sometimes beds with a lot of metal or the WiFi router can cause interference. A patient only needs to find an alternative location.
Those daily pressure readings allow the person’s cardiologist to determine if medication needs to be adjusted before the person gets sick enough to feel increased symptoms and require hospitalization. A buildup of fluid that causes symptoms can take weeks to develop.
In patients whom Coyle has equipped with the CardioMEMS, he has been able to see trends in their pressure percentages and adjust medication. If there is a worrying reading, Coyle or a nurse will ask about symptoms and blood pressure to determine what is causing the pressure change.
“The people I try to target are the ones who are very symptomatic, they have a lot of fluctuations in their fluid status, they are constantly walking on the fine line of needing high doses or constantly needing a change of doses,” Coyle said . “This takes the guesswork out. There’s more continuous feedback. We have a better idea of where the (liquid) volume is.”
It won’t work for people who aren’t consistent with their care, Coyle said. If they don’t take their medication regularly, if they miss doctor’s appointments, the CardioMEMS is not for them.
“It takes a person who is highly motivated,” Coyle said. “It has to become part of their daily routine. I get on the scale and check my weight. I check my blood pressure. I do my CardioMEMS.”
Now, every morning, Carver lays down on the mat, which he describes as a pillow with a hard frame and a pillow on top. He presses the button and remains still on the mat for 10 seconds. Then he leaves it plugged in while it sends its reading to Coyle’s office in Marble Falls. He makes his breakfast and pulls the plug out of the socket.
“If there’s a problem, someone will call me,” he said.
Usually no one calls him, but when he traveled to Colorado and brought the mat with him, he got a call. The high altitude had affected his heart and the pressure in his pulmonary artery.
“They read them every morning,” he said. “I’m impressed.”
If the readings change, Coyle is able to adjust Carver’s meds before it becomes a situation where Carver has to be hospitalized.
Now that Carver is well controlled with medication, he realizes how sick he was before. The former baseball coach and player said he felt tired and irritable.
“I felt exhausted and felt like something wasn’t right,” he said. “When I started exercising, I noticed that I couldn’t breathe. The harder I trained, the worse it got. I couldn’t put my finger on it.”
He now knows that his heart couldn’t keep up with all the fluids and that it had to work overtime to keep up.
Now Carver can walk two miles every morning. He mows his own lawn, he stains his patio.