Wireless pacemakers, temporary heart pumps and dyeless digital imaging.
In the assessment of medical professionals, this is “an exciting time” to be working in cardiology.
In recent months three very new devices and technical innovations have been implemented by Dr. Kevin Fullin, interventional cardiologist and the heart team at Froedtert South.
Micra: the world’s smallest pacemaker
Last fall, Fullin implanted a tiny wireless pacemaker known as the Micra Transcatheter Pacing System.
Approved by the FDA for use in 2016, this is a 1-inch-long device about the size of a vitamin capsule. Where conventional pacemakers consist of a transmitting device plus one to three wire leads, the Micra is an all-in-one unit.
“Traditional pacemakers have helped a tremendous amount of patients keep their heart rates from going too slow and restarting their hearts,” Fullin said.
On the other hand, he said, “the leads move with every heartbeat, and so with time they can fracture, and then we have to put a new lead in.”
Another downside to wire leads is a susceptibility to contamination from viruses in the body. In this case, the wires have to be removed and replaced.
Other problems might include in-vessel bleeding, or in very rare cases a punctured lung during implant surgery.
The Micra bypasses all of these issues, so to speak.
Inserted via a catheter from the groin, the enclosed tube containing a battery and pacing device has four tiny flexible anchors that attach to the fibrous tissue of the heart.
“Once we confirm it is pacing well and anchored well, it detaches it from the catheter,” Fullin said.
The Micra lasts 15 years; traditional pacemakers last 10.
“A bonus fact is that because the Micra is so small, in the event it needs replacing, the surgeon won’t remove the first one, but can leave it in and just add a new one right next to it,” Fullin said.
Fullin said the Micra will be particularly helpful for patients for whom pacemaker lead infection has been an issue or for those with already infected pacemakers.
The current generation of the Micra only paces in one chamber and so will be used only for patients who need only a single chamber to be paced.
While standard pacemakers can pace more than one chamber, additional wire leads are required for each chamber that is paced.
“(The Micra) is ideal for patients who have something like ulcerated sores somewhere on the body and can’t risk getting the infection transferred onto pacemaker leads,” Fullin said.
“We are very excited about this because this is safer for some patients where the risk of these other things is very high,” Fullin said.
Another innovation is aortic imaging.
To see what’s going on inside the heart and its vessels in real time, cardiologists have used contrast injection with digital imaging in a procedure known as angiography.
Traditionally this is done using a contrast media or dye that travels through the body’s vein network. This dye, however, can be hard on the kidneys to process.
Finding a way to get those same real-time pictures without dye has become another exciting boon to cardiology, say experts.
Last fall, Fullin and the heart team stented a kidney artery using CO2 imaging, a process involving the injection of a small amount of carbon dioxide rather than dye into the patient’s system.
“With this patient we suspected blockage in the kidney arteries. But to see it, we would need to use dye, but that would make it worse. We could have used medication to try to prevent this (side effect) but better yet to use (CO2 imaging),” Fullin said.
Using the CO2mmander from AngioAdvancements, the surgical team was able to capture the needed images using only 10 cc of CO2 where with dye they would have had to administer a 120 cc dose.
“10 cc doesn’t hurt the kidney; 120 cc does,” he said.
Fullin said that physicians have known for a long time that CO2, a component of air, could provide contrast images. Eventually the technology developed by which CO2 could be compressed, packaged and utilized.
“Air, which is a mixture of gases, would be lethal if injected into the body; pure carbon dioxide, however, is absorbed by the tissues,” he said.
Carbon dioxide angiography is especially helpful to patients with “fairly common” conditions including, kidney damage, leg arteries and leg aneurysms, Fullin said.