In vitro mitral chordal cutting by high intensity focused ultrasound.
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).
Abe
Yukio
Y
Department of Medicine Cardiology Division, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. abeyukio@aol.com
Otsuka
Ryo
R
Muratore
Robert
R
Fujikura
Kana
K
Okajima
Kazue
K
Suzuki
Keiko
K
Wang
Jie
J
Marboe
Charles
C
Kalisz
Andrew
A
Ketterling
Jeffrey A
JA
Lizzi
Frederic L
FL
Homma
Shunichi
S
D000818:Animals; D002417:Cattle; D002815:Chordae Tendineae; D005240:Feasibility Studies; D006801:Humans; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000473:pathology; D008944:Mitral Valve Insufficiency / Q000473:pathology / Q000628:therapy*; D023421:Models, Animal; D014159:Transducers; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*; D014463:Ultrasonography