Aortic valvuloplasty in the fetus: Technical characteristics of successful balloon dilation
ABSTRACT To describe technical aspects of successful fetal aortic valvuloplasty, with particular attention to balloon size.
We retrospectively reviewed all procedural records and echocardiograms pertaining to 26 attempts at fetal aortic valve dilation performed at a single center over a period of 4 years. We assessed the effect of valvuloplasty as determined by echocardiographic appearance at the time of intervention and in follow-up.
In 20 of 26 fetuses who had technically successful aortic valve dilation (median balloon:annulus ratio=1.1), all had improved antegrade flow and 12 had at least mild regurgitation after dilation. Use of an oversized balloon was associated with the onset of moderate or severe aortic regurgitation, seen in 5 fetuses. This aortic regurgitation was well tolerated and improved through the remainder of gestation.
These data imply that fetal aortic valves can be dilated safely with larger balloons than are commonly used for postnatal dilation. The observation of spontaneous improvement in postdilation aortic regurgitation further suggests that fetal valve tissue behaves uniquely.
- SourceAvailable from: Jacqueline Kreutzer
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- "Based on the published methods for human fetal cardiac intervention      and personal experience, we selected needles, wires, and catheters currently in use in the human fetus. A standard thin-walled Cook 19-gauge intravascular needle (DTN-19UT-11.5-M3, "
ABSTRACT: Objectives. Multiple technical difficulties are encountered when a multidisciplinary team of subspecialists begins a minimally-invasive fetal cardiac interventional program. We describe the learning curve. Study Design. Ten pregnant sheep underwent ultrasound-guided balloon valvuloplasty of the aortic valve. Team members and their roles remained constant through the trial. The time between needle insertion and entrance of the left ventricle at the aortic root was recorded. F-test was used to assess significance (P ≤ .05). Results. The time required to accurately position the needle tip at the aortic root decreased significantly over the course of the trial, from 12 minutes with the first attempt to one minute with the last (P = .003). Conclusion. A significant learning curve is encountered when a multidisciplinary team begins a minimally-invasive fetal cardiac intervention program. However, technical proficiency can be achieved with practice. Institutions interested in developing such a program should consider practice in an animal model before proceeding to the human fetus.03/2010; 2010(6):674185. DOI:10.1155/2010/674185
Conference Paper: On the use of filter design programs for generating spectral windows[Show abstract] [Hide abstract]
ABSTRACT: In processing long sequences of data either for the purpose of filtering or spectal analysis, one generally divides the data into segments. The elements of each segment are usually multiplied by a set of weights, referred to as a "window", to reduce certain undesired effects of the division into short sequences (see Ref. 1). A simple effective way to design a window is to use one of the many window functions such as the Hanning, Hamming (1) or Kaiser (2) windows. These are defined by simple formulas in which parameters can be selected so that the frequency response of the window will have the desired center-lobe width and side-lobe attenuation. These procedures have the advantage that they require no more than a pocket calculator. On the other hand, if one is equipped with a large computer with filter design programs such as those in the IEEE Program Book (3), one may find it easier, in some cases, to design better windows by the direct calculation of an optimized filter. The present work shows the results of computations of FIR filters and how they compare with Hanning, Hamming and Kaiser windows. We get, for typical filter parameters, a side-lobe attenuation of 31.5 dB for the Hanning window, 42.0 dB for the Hamming window, 41.0 dB for the Kaiser window and 47.2 dB for the FIR window.Acoustics, Speech, and Signal Processing, IEEE International Conference on ICASSP '81.; 05/1981
Article: Fetal surgery.[Show abstract] [Hide abstract]
ABSTRACT: Fetal surgery has come of age. For decades experimental fetal surgery proved essential in studying normal fetal physiology and development, and pathophysiology of congenital defects. Clinical fetal surgery started in the 1960s with intrauterine transfusions. In the 1970s, the advent of ultrasonography revolutionized fetal diagnosis and created a therapeutic vacuum. Fetal treatment, medical and surgical, is slowly trying to fill the gap. Most defects detected are best treated after birth, some requiring a modification in the time, mode and place of delivery for optimal obstetrical and neonatal care. Surgical intervention in utero should be considered for malformations that cause progressive damage to the fetus, leading to death or severe morbidity; that can be corrected or palliated in utero with a reasonable expectation of normal postnatal development; that cannot wait to be corrected after birth, even considering pre-term delivery; that are not accompanied by chromosomal or other major anomalies. At present, congenital hydronephrosis is the most common indication for fetal surgery, followed by obstructive hydrocephalus. Congenital diaphragmatic hernia also fulfills the criteria, but its correction poses more problems, and no clinical attempts have been reported so far. In the future many other malformations or diseases may become best treated in utero. The ethical and moral issues are complex and need to be discussed as clinical and experimental progress is made.Canadian family physician Médecin de famille canadien 10/1986; 32:2099-103. · 1.40 Impact Factor