Project Summary
Valvular heart disease is an important health problem afflicting over 2.5% of the US population and catheter-
based therapies to address it have advanced significantly in recent years. While surgical repair remains the
gold standard, the reduced risk of catheter-based interventions has provided the ability to intervene earlier in
the disease process and in patients too sick for surgery while avoiding the risks of cardiopulmonary bypass.
A significant limitation of these procedures, however, is that they do not provide the capability to remove
native tissue and previously implanted devices to tailor the anatomy to receive a new prosthetic device. For
example, transcatheter valves rely on displacing the diseased valve leaflets rather than removing them. In
transcatheter aortic valve replacement, the displaced leaflets can obstruct blood flow to the coronary arteries
and prevent access for subsequent coronary interventions. In transcatheter mitral valve replacement, the
native anterior leaflet can be forced into the left ventricular outflow tract resulting in restricted flow into the
aorta. Recently, a transcatheter technique has been introduced to lacerate a leaflet along its midline from
base to tip. When performed prior to transcatheter valve replacement, the new valve spreads the two halves
of the old leaflet apart so that they do not interfere with blood flow. This innovative approach can increase the
number of patients who qualify for these low-risk procedures. Since the procedure relies on the use of existing
guidewires and catheters, however, it is technically challenging, requires multiple clinicians to perform and
takes more time than valve replacement. Furthermore, the electrosurgical ablation used in these procedures
is not as effective for calcified tissue which is often present in native and bioprosthetic leaflets. To address
this need, we propose to develop a catheter-based technology that enables a single operator to perform
precise cutting of native and bioprosthetic leaflets regardless of calcification. In Aim 1, we will develop a
steerable cardioscopically-guided leaflet cutting catheter. We will develop and demonstrate the technology in
the context of aortic and mitral leaflet modification using electrosurgical cutting. In Aim 2, we will create a
laser-based leaflet cutting system to address the limitations of electrosurgery in calcified tissue. The
technology will be evaluated through in vivo testing and comparison with existing methods. Key innovations
of this research include real-time optical visualization of leaflets during cutting, the ability to cut a leaflet without
forming a wire loop through it, the development of laser-based cutting to precisely lacerate calcified tissue
and the characterization of emboli produced by leaflet laceration. This technology can provide a platform for
the future development of more sophisticated transcatheter tissue modification and device removal
procedures.
