Small technology with big impact

Heart failure management in a capsule; help connecting small blood vessels; and exponentially improving spinal implant success.

By David Geer | Spring 2015 | Tech Notes

 

If you treat heart failure, cancer or spinal maladies, you’ll be delighted to read how shrinking medical technologies are sparking undeniable improvements in your patients’ quality of life.

The CardioMEMS HF System helps physicians monitor pulmonary artery pressure from afar

To learn more about the CardioMEMS HF System for comprehensive heart failure management, visit sjm.com/cardiomems.

St Jude Medical Logo No Tag 1950X664

The CardioMEMS HF System tool for comprehensive heart failure management is in its first generation, says Mark Carlson, M.D., chief medical officer of St. Jude Medical in St. Paul, Minnesota. “It is the first and only FDA-approved heart failure (HF) monitor proven to significantly reduce HF hospital admissions and improve quality of life in NYHA Class III patients when managed by physicians,” he says.

The CardioMEMS HF System uses a miniaturized wireless sensor in a sealed capsule form factor, which is implanted into the patient’s pulmonary artery during a minimally invasive operation. The encapsulated sensor measures the pulmonary artery (PA) pressure and transmits the pressure readings to an external electronic system in the patient’s home.

“The system allows patients to transmit PA pressure data from their homes to their health care providers, allowing for personalized and proactive management to reduce the likelihood of hospitalization,” says Carlson.

CardioMEMS Miniaturized Sensor

The CardioMEMS HF System transmits pressure readings.

The miniscule sensor functions without batteries or leads and does not produce any sensation in the patient either at the time of the readings or otherwise.

Rami Kahwash, M.D., is an assistant clinical professor in cardiovascular medicine at Ohio State University in Columbus. Kahwash was looking for a tool to measure and trend data on fluid retention in the lungs. Because fluid builds up over a couple of weeks prior to the resulting clinical event or hospital readmission, such a tool would enable Kahwash to intervene well ahead of such an event to give just-in-time care.

In the past, Kahwash and his colleagues tried to manage heart failure patients and adjust medications based on weight. “However, that turned out not to be very sensitive,” he says.

Today, Kahwash uses the CardioMEMS sensor, which provides an early warning as to the status of the pressure inside the lungs. “The pressure inside the lungs is really reflective of what’s going on inside the heart,” he says.

CardioMEMS

“This sensor gives us this information while the patient is at home, so we now have the luxury of simply sitting in our clinic while the patient and the technology send us the measurements every day,” Kahwash says. The system retrieves the data and receives it in a secure website where physicians can review it daily. With that information, Kahwash and his colleagues can intervene with therapy or by changing the patient’s medication dosage prior to an acute heart failure event.

Kahwash’s favorite CardioMEMS feature is the durability of the sensor. “In the CHAMPION study, sensor failure was almost at 0 percent,” he says. And any cardiologist can implant the device.

Kahwash would like to see an even smaller sensor and an improvement in the ability to know when the patient sends the data. “The sensor is pretty small, but there is maybe some room in the future to make it smaller,” says Kahwash. “And the patients currently send the data to the website and we wait until we log into the website to see the measurements. Perhaps the system could alert us when there is an abnormal trend.”

The GEM FlowCoupler joins very small blood vessels

To learn more about the GEM FlowCoupler, visit synovismicro.com.

GEM Logo

“The GEM FlowCoupler mechanically joins very small diameter blood vessels from about 0.08 mm in diameter up to about 4.3 mm in diameter,” says Terry Harrell, Director of Sales for Synovis Micro Companies Alliance, Inc., in Birmingham, Alabama. The GEM FlowCoupler includes Doppler technology for monitoring blood flow.

The GEM FlowCoupler enables an intima-to-intima vessel anastomosis that meets very high standards, stenting the anastomic site open in about five minutes, says Harrell.

Daniel Liu, M.D., is a board-certified plastic and reconstructive surgeon at Cancer Treatment Centers of America at Midwestern Regional Medical Center in Zion, Illinois, where he works on breast cancer reconstruction. Liu was looking for a better, faster way to join blood vessels than simply suturing them in a relatively long procedure using standard microsurgical instruments under a microscope. Liu found what he was looking for in the GEM FlowCoupler.

FlowCoupler

“The introduction of the GEM FlowCoupler eliminates sewing one of the blood vessels, which considerably cuts down the time we spend on the microscope,” he says. The GEM FlowCoupler works well when joining veins. Liu still must sew the artery because its wall is more dense, which is not compatible with how the GEM FlowCoupler works.

The GEM FlowCoupler makes the work of the assisting surgeon easier as well. When using sutures, the assisting surgeon has to be attentive to ensure there’s no unnecessary blood vessel trauma. “With the GEM FlowCoupler, the assistant has an easier job, holding the coupling device, while I stretch the vessels onto the tines of the coupler,” says Liu.

The benefits of the GEM FlowCoupler include increased patient safety. “The veins are flimsy and in a low-flow state. Blood can clot or the vein can compress, causing a total failure of the operation. Because the coupler is a rigid ring, it actually stents the vessel open at the weakest point,” he says.

Other GEM FlowCoupler features Liu appreciates include its ease of use and the fact that the learning curve leading up to using the device is small. “We often train our residents and fellows to do this with ease,” he says.

For future improvements, Liu would like to see the vendor come up with a technology that can overcome the artery’s rigid state, as well as a means to overcome the size mismatches between the different sized couplers and the veins—the challenges with arteries would probably require a completely different type of engineering, he says.

The 4WEB Spine Truss System improves patient outcomes

To learn more about the 4WEB Spine Truss System, visit 4webmedical.com.

4WEB

4WEB Medical uses multidisciplinary engineering principles such as structural mechanics and adjacent material reaction to create implants for spine fusion surgery that actively participate in and accelerate the healing process, according to Jim Bruty, vice president of sales and marketing for 4WEB Medical in Frisco, Texas.

The vendor designed its implants to create faster fusions while potentially reducing the chance of complications that physicians would find with existing devices on the market, says Bruty.

“4WEB Medical produced the first-ever FDA cleared 3-D printed spine inter-body fusion device,” says Bruty.

Cameron Noble Carmody, M.D., is an orthopedic spine surgeon at Plano Orthopedics Sports Medicine and Spine Center in Texas.

“As an orthopedic surgeon, I am always looking for implants that have the potential to improve patient outcomes, decrease post-operative pain, and minimize the risk of subsidence, non-union and other implant-related complications,” he says.

4WEB

Prior to finding 4WEB trusses, Carmody used osteobiologics as well as rigid internal fixation and anterior column support methods. Osteobiologics are a relatively expensive option. “And there was always a race between bone growth and fusion and the mechanical stability of the instrumentation over time,” says Carmody. This means that the bone might not always grow across the gap from end-plate to end-plate and start to share the load transmission with the implants before the effects of subsidence or screw interface loosening or even hardware failure set in, leading to micro-motion and non-union.

But the 4WEB web design, anatomic shape and textured titanium material stabilize the new state of the spine and provide uniform load distribution across the end-plate, avoiding these potential complications. “And due to the open-architectural design, there is always ample room for bone,” says Carmody.

Carmody’s favorite 4WEB truss features include the early stability and the maximum contact area of the trusses, the many sizes and shapes available, and the science that suggests that the truss structure and titanium surface work together under load to promote bone growth.

The 4WEB truss is on its way to meeting all of Carmody’s hopes for spinal truss implants. As the additive manufacturing science blossoms, according to Carmody, 4WEB should be able to decrease the Effective Elastic modulus of the titanium implants not only to that of PEEK but to that of cancellous bone. “This technology will soon meet Nakajima’s seven criteria for the perfect bone implant,” he says.

David Geer is a frequent contributor to PracticeLink Magazine’s Tech Notes department.

 

Comments are closed.