FDA Reviews Expansion of CRT-D, Implantable Heart Failure BP Monitor
October 18, 2011 — A U.S. Food and Drug Administration (FDA) committee will discuss and make recommendations to expand Medtronic’s indication for its cardiac resynchronization therapy defibrillator (CRT-D) in Class II heart failure patients. The committee will also review a pre-market approval (PMA) application for CardioMEMS’ Heart Failure Pressure Measurement System (HF system).
The FDA Circulatory System Devices Panel of the Medical Devices Advisory Committee will discuss these items during its meeting Dec. 7-9, 2011, in Gaithersburg, Md.
Medtronic is requesting FDA approval to expand the indications for use for all commercially available Medtronic CRT-D devices. The company proposed expanding the indication based on the results of the REVERSE and RAFT clinical studies. The indication would be expanded to New York Heart Association (NYHA) Functional Class II patients who remain symptomatic despite stable, optimal medical therapy; Class II patients would also have left bundle branch block (LBBB) with a QRS duration ≥120 ms, and left ventricular ejection fraction ≤30 percent.
On Dec. 8, the committee will discuss, make recommendations, and vote on information related to the PMA for the HF system. It is a permanently implantable pressure measurement system designed to provide daily pulmonary arterial pressure measurements including systolic, diastolic, and mean pulmonary artery pressure. These measurements are used to guide treatment of congestive heart failure.
The system consists of an implantable pressure sensor 15 mm in length, 3.41 mm in width and 2 mm thick. It has a three-dimensional coil and pressure sensitive capacitor encased between two wafers of fused silica. The coil (inductor) electromagnetically couples to the sensor and allows remote measurement of the resonant frequency of the LC circuit. This allows for wireless communication with the sensor and eliminates the need for an onboard source of energy, such as a battery.
The delivery system allows the placement of the sensor within the distal pulmonary artery. There are two versions of the delivery system; the first includes a hydrophilic coating on the distal portion of the catheter shaft and the second has no coating. Both delivery catheters have a usable length of 120 cm and are compatible with a 0.018 in. guidewire.
The delivery system (with HF sensor) is introduced over a guidewire through an 11 French sheath. Tether wires connect the sensor to the delivery system until the physician determines the sensor is properly positioned within the distal pulmonary artery. Once the sensor is in position, the tether wires are withdrawn, releasing the sensor electronics unit (Interrogator) and database.
The system uses an electronics unit containing hardware and software to acquire and process signals from the sensor. It also provides a user-friendly system interface for both patients and clinicians and transfers PA measurements to a secure Web-based server for review by medical professionals.
For more information: www.fda.gov