James Watson was a walking time bomb and didn't know it. During a CT scan performed for abdominal pain, Emory doctors discovered an abdominal aortic aneurysm (AAA). Now Watson has an implanted wireless microchip sensor designed to detect endoleaks with the potential to cause a fatal rupture.
Emory vascular surgeon Ross Milner, MD. Assistant Professor of Vascular Surgery, Emory University School of Medicine, implanted the sensor device during the repair of Watson's AAA with an endovascular graft. Created by Atlanta-based CardioMEMS, the sensor monitors pressure in the aneurysm sac. And instead of a lifetime of periodic CT scans every six to 12 months like most endograft repair patients, Watson's aneurysm pressure readings can be taken using a remote device equipped with an antenna.
"They wave it over your body and you can't feel a thing," says the 76 year-old Watson.
The CardioMEMS device was implanted as part of the Acute Pressure Measurement to Confirm Aneurysm Sac Exclusion (APEX) Trial. The FDA approved the procedure for investigational purposes, but it is expected to receive FDA approval this year. Emory vascular surgeons first performed the procedure in October 2004 and to date have placed a total of seven implants.
"We'll continue to stay on the leading edge of the field with this study and others," Dr. Milner says. "The CardioMEMS device has the potential to dramatically change our follow-up for patients after endovascular aneurysm repair."
Watson was more than ready to receive the pressure sensor.
"This was an opportunity to put the device in and monitor the pressure in hopes that it could be used to help other people in the future," he says. "It seems that in the future it may be developed further so you may be able to hold the telephone receiver against the sensor and monitor it."
Aneurysms are typically repaired with stent grafts that isolate an aneurysm from pressure by forming a new pathway for blood flow. Still, blood may leak into the sac and cause a rupture, hence the need for patients to undergo routine exams to monitor their pressure on a regular basis. The CardioMEMS pressure sensor is implanted in the aneurysm sac and is able to detect any abnormal pressure changes after the aneurysm repair.
Although hospital visitations are still required to monitor the pressure, patients with the implant do not have to endure the injectable contrast agents (that can cause liver damage) used during the CT scans. Also, it's likely that an aneurysm can have elevated pressure even if there is not a visible endoleak on a CT scan.
The majority of AAA repair patients are potential candidates for the study as long as there is enough of a blood channel remaining within the aneurysm in order to place the sensor, Dr. Milner says.
The Division of Vascular Surgery and Endovascular Therapy of Emory University continues to strive towards excellence in clinical and research endeavors. Their continuing shift from open to catheter-based surgical interventions whenever possible has earned the vascular surgeons recognition as national leaders in training, research, and performance of endovascular procedures.