In Vitro Mitral Chordal Cutting by High Intensity Focused Ultrasound

Abe, Yukio; Otsuka, Ryo; Muratore, Robert; Fujikura, Kana; Okajima, Kazue; Suzuki, Keiko; Wang, Jie; Marboe, Charles; Kalisz, Andrew; Ketterling, Jeffrey A.; Lizzi, Frederic L.; Homma, Shunichi

doi:10.1016/j.ultrasmedbio.2007.09.003

« Previous Next »Ultrasound in Medicine and Biology
Volume 34, Issue 3 , Pages 400-405, March 2008

In Vitro Mitral Chordal Cutting by High Intensity Focused Ultrasound

Yukio Abe
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Address correspondence to: Yukio Abe, MD, Department of Medicine Cardiology Division, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH3-133, New York, NY 10032 USA.
Ryo Otsuka
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
Robert Muratore
- Riverside Research Institute, New York, NY, USA
Kana Fujikura
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
Kazue Okajima
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
Keiko Suzuki
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
Jie Wang
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
Charles Marboe
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
Andrew Kalisz
- Riverside Research Institute, New York, NY, USA
Jeffrey A. Ketterling
- Riverside Research Institute, New York, NY, USA
Frederic L. Lizzi
- Riverside Research Institute, New York, NY, USA
Shunichi Homma
- College of Physicians and Surgeons, Columbia University, New York, NY, USA

Received 28 March 2007; received in revised form 16 July 2007; accepted 5 September 2007. published online 08 November 2007.

Abstract

Mitral regurgitation, when it arises from functional restriction of mitral leaflet closure, can be relieved by surgical cutting of the mitral tendineae chordae. We hypothesized that high intensity focused ultrasound (HIFU) might be useful as a noninvasive extracorporeal technique for cutting mitral chordae. As a pilot study to test this hypothesis, we examined the in vitro feasibility of using HIFU to cut calf mitral chordae with diameters from 0.2 to 1.6 mm. Sixty-seven percent of chordae were completely cut with HIFU, operated at 4.67 MHz and 45 W acoustic power, with up to 120 pulses of 0.3-s duration at 2-s intervals. Forty-five percent were completely cut when the pulse duration was reduced to 0.2 s. The average diameter of those chordae, which were completely cut, was significantly smaller than that of incompletely cut chordae (0.59 ± 0.30 versus 1.14 ± 0.30 mm with a pulse duration of 0.2 s, p < 0.0001; 0.68 ± 0.29 versus 1.32 ± 0.20 mm with a pulse duration of 0.3 s, p < 0.0001). For each pulse duration, the number of pulses required for complete cutting exhibited a strong positive correlation with the chordae diameter. In conclusion, in vitro feasibility of mitral chordal cutting by HIFU depended on the diameter of chordae but was controllable by HIFU settings. (E-mail: abeyukio@aol.com)

Key Words: High intensity focused ultrasound, Tendineae chordae, Therapeutic ultrasound, Ultrasound surgery, Mitral regurgitation