SBIR-STTR Award

Approximately 1% of babies born require operative treatment for congenital heart diseases. Worldwide, 80,000 pediatric cardiac procedures are performed annually. These procedures are all performed postnatally. However, based on a growing recognition that earlier anatomic repair is beneficial to the health of the child, it has become clear that prenatal cardiac intervention (PCI), though revolutionary, is highly desirable to correct aortic valve stenoses and other abnormalities that lead to hypoplastic left heart syndrome (HLHS). At the same time the technology available for PCI is clearly deficient. Ours is a proposal to begin a multi-phase effort to realize technologies and interventional techniques that will make it possible to perform extraordinarily delicate and intricate cardiac procedures on a fetus while it is in the mother's womb, i.e., using minimally invasive in utero techniques. The overall concept is to provide the interventionalist graphical displays, navigation aids and in vivo sensing capabilities that enable a PCI and confirm its efficacy. The essence of our approach is to make minor augmentations of the equipment and devices currently used for PCI, but in so doing to make a significant increase in the information content provided to the interventionalist. The specific research proposed here is to develop an optical position tracking solution for instruments used in PCI that will enable their relative locations to be measured with high accuracy and in real time. Based on those data, a graphical display that combines ultrasound imagery and navigation data will readily created. With this real time display, the interventionalist will have the means to visualize the exact location of catheters and introducers even if they not clearly evident in the ultrasound images. Further, the display will show other salient geometric features, such as the trajectory a catheter will follow if it is inserted further and distances and angles between that tool path and the ultrasound image. The prototype system will be based on three technologies we have developed for orthopaedic surgery. This research will be conducted in partnership with Carnegie Mellon University's Robotics Institute and the Cardiology Department of Children's Hospital of Pittsburgh. In Phase Two, we will conduct in vivo tests of the sensors in appropriate animal models.

Thesaurus Terms:
biomedical equipment development, cardiovascular imaging /visualization, cardiovascular surgery, computer assisted patient care, congenital heart disorder, embryo /fetus surgery, technology /technique development aortic valve stenosis, heart catheterization, heart ventricle, three dimensional imaging /topography, ultrasonography bioengineering /biomedical engineering, bioimaging /biomedical imaging, ultrasound imaging /scanning

There is growing recognition that surgical repair of the heart is most likely to be successful in infancy (when there is dramatic capacity for growth and remodeling). For a subset of patients, the optimal time for intervention is prior to birth. Current prenatal cardiac intervention (PCI) procedures clearly have technical limitations in both fetal visualization and instrumentation, taking up to 220 minutes, and often further surgery for the mother. Global Hypothesis: Integration of customized, computer-assisted, surgical visualization and navigation techniques into PCI will reduce procedural time and improve accuracy leading to improved fetal outcomes. The Phase II Specific Aims are: Specific Aim 1: Optimize software and hardware to exceed accuracy requirements for fetal probe positioning and tracking. Integration of new high-resolution ultrasound and tracking equipment will optimize system accuracy and image quality. The ultrasound probe calibration protocols will be made more robust, accurate, and ergonomic. Repeat phantom experiments will confirm accurate visualization and localization performance acceptable for human fetal application. Specific Aim 2: Optimize the computer-assisted PCI (CAPCI) user interface to maximally reduce procedure time. In Aim 2 the user interface will be optimized to increase ease of use, speed, accuracy, and image content during simulated PCI, overcoming the limitations of the Phase I prototypes. Specific Aim 3: Test the increased accuracy and efficiency of CAPCI in small and large animal trials. Following initial validation trials using in vitro phantom heart targets, the success of the CAPCI system will be determined by experiments that position a fetoscope and balloon catheter through the chest wall, left ventricular apex, and then across the aortic valve of an adult rat. Finally, further experiments will determine the success of CAPCI in catheter positioning across the aortic valve in the mid-gestation fetal sheep. These experiments will provide proof of principle to begin clinical trials. Significance: The development of computer-assisted methods to optimize PCI will increase the accuracy (and reduce the length of maternal anesthesia) of these procedures with a direct impact on procedural success. This technology has broad applicability to other ultrasound-guided procedures in the fetus, child, and adult.

Thesaurus Terms:
computer assisted patient care, computer system design /evaluation, embryo /fetus surgery, heart surgery, image guided surgery /therapy aortic valve, computer system hardware, phantom model bioimaging /biomedical imaging, laboratory rat, sheep, ultrasound imaging /scanning