How do most Americans meet their demise? It's a question as serious as a heart attack.
According to the Centers for Disease Control, about 600,000 people die of heart disease in the United States every year.
That's right, one in four Americans kick off from heart disease.
The leading cause of death for both men and women, slightly more than half of those lost to heart disease in 2009 were men, and coronary heart disease is the most common type of the ailment among both sexes. Coronary heart disease kills more than 385,000 people every year in the United States, and each and every year, some 715,000 Americans suffer the agonizing pain of a heart attack.
Coronary heart disease, by and of itself, costs the United States $108.9 billion annually and that total includes the cost of health care services, medication, and lost workplace productivity.
Now a new 3D printed implant capable of delivering treatment – or even predicting an impending heart attack before a patient shows any physical symptoms – has been built by researchers using 3D printing technology.
The implantable device can be custom-fit to a patient and includes embedded sensors which could one day revolutionize the way patients with cardiac disorders are treated.
It consists of an elastic membrane made from a soft, flexible, silicon material shaped to follow the contours of the heart's outer wall. The research shows minute sensors can be printed on that membrane which are capable of measuring a patient's temperature, detecting mechanical strains and certain critical pH markers.
The scientists say the implant could also deliver a surge of electricity to interrupt arrhythmia conditions and get a patient's heartbeat back on track.
"Each heart is a different shape, and current devices are one-size-fits-all and don't at all conform to the geometry of a patient's heart," said Igor Efimov, a researcher at Washington University in St Louis. "With this application, we image the patient's heart through an MRI or CT scan, then computationally extract the image to build a 3D model that we can print on a 3D printer. We then mold the shape of the membrane that will constitute the base of the device deployed on the surface of the heart."
Efimov sees the device as a sort of "all-round" membrane inserted inside the heart to treat a variety of maladies.
"Medical devices to treat heart rhythm diseases are essentially based on two electrodes inserted through the veins and deployed inside the chambers," Efimov said. "What we want to create is an approach that will allow you to have numerous points of contact and to correct the problem with high-definition diagnostics and high-definition therapy."
The findings were published in Nature Communications.
John Rogers at the University of Illinois at Urbana-Champaign worked with Efimov to create the elastic, silicon membrane. It was fit to a beating rabbit heart and monitors various markers of cardiac health.
"What John has developed here opens up a whole new tool kit for high-resolution cardiac monitoring and stimulation-based therapy," Efimov said.
Using optical scanning techniques, the team reconstructed the exterior geometry of the rabbit heart and then used the files to 3D print a precision replica. The researchers mounted wafer-thin electronic components and ribbon cables before encasing the device inside a thin layer of silicon elastomer.
"The membrane is a little bit smaller than the heart, so you have to stretch it to slip it on," Rogers explained. "That's important, because you need some pressure to achieve good contact with the heart surface, but not so much that it restricts function."
The innovation lies in the fact that the team integrated a range of functionality into the membrane that covers the entire surface of the heart. It's the coverage of the sensors which provides a greater depth spatial resolution for cardiac monitoring and control of any applied stimulation pulses. The idea is that this type of membrane might one day replace implantable defibrillators and pacemakers. Efimov says that the additional pH sensors could be used to predict sudden cardiac arrest by detecting the conditions of ischemia, the reduced blood flow which often presages a heart attack.
Rogers says heart attack detection might come via an integrated "troponin sensor." Troponin levels (a protein group which controls cardiac muscle contraction) could be monitored to determine the extent to which the heart has suffered damage. High levels of troponin are the indicator, and he says checking troponin levels in real time might save lives.