This is a prepublication version of an article that has undergone peer review and been accepted for publication but is not the final version of record. This paper may be cited using the DOI and date of access. This paper may contain information that has errors in facts, figures, and statements, and will be corrected in the final published version. The journal is providing an early version of this article to expedite access to this information. The American Academy of Pediatrics, the editors, and authors are not responsible for inaccurate information and data described in this version.

BackgroundPulmonary arterial hypertension (PAH) is a devastating disease with significant morbidity and mortality. At the macroscopic level, disease progression is observed as a complex interplay between mean pulmonary artery pressure, pulmonary vascular resistance, pulmonary vascular stiffness, arterial size, and flow. Wall shear stress (WSS) is known to mediate or be dependent on a number of these factors. Given that WSS is known to promote architectural vessel remodeling, it is imperative that the changes of this factor be quantified in the presence of PAH.MethodsIn this study, we analyzed phase contrast imaging of the right pulmonary artery derived from cardiovascular magnetic resonance to quantify the local, temporal and circumferentially averaged WSS of a PAH population and a pediatric control population. In addition, information about flow and relative area change were derived.ResultsAlthough the normotensive and PAH shear waveform exhibited a WSS profile which is uniform in magnitude and direction along the vessel circumference at systole, time-averaged WSS (2.2 ± 1.6 vs. 6.6 ± 3.4 dynes/cm2, P = 0.018) and systolic WSS (8.2 ± 5.0 v. 20.0 ± 9.1 dynes/cm2, P = 0.018) was significantly depressed in the PAH population as compared to the controls. BSA-indexed PA diameter was significantly larger in the PAH population (1.5 ± 0.4 vs. 0.7 ± 0.1 cm/m2, P = 0.003).ConclusionsIn the presence of preserved flow rates through a large PAH pulmonary artery, WSS is significantly decreased. This may have implications for proximal pulmonary artery remodeling and cellular function in the progression of PAH.

Background Cardiac catheterization remains the standard diagnostic technique for assessing both anatomy and physiology in congenital heart disease (Chd). fixed projection angiography (fpa) is the mainstay for guiding congenital cardiovascular interventions. however, fpa has limitations in soft tissue visualization and precise characterization of complex structures such as segmental branch pulmonary arteries, coronary arteries, and anomalous or stenotic pulmonary veins. these limitations are due in part to simultaneous opacification of overlying structures, foreshortening of structures if the projection is not perfectly aligned, and the inability to visualize structures without injection of contrast. integration of 3-dimensional (3d) image data sets with fluoroscopy can potentially overcome limitations of 2-dimensional (2d) angiography for visualizing complex vascular structures and can facilitate accurate diagnoses as well as guide interventional procedures. the use of 3d images obtained from 3d rotational angiography (3dra), Ct, and Mri was originally developed for neuroradiographic endovascular procedures 1-3 but has played an increasing role in cardiovascular medicine for anatomic delineation 4-7 and electroanatomic mapping. 8 rotational angiography (ra) and 3dra have emerged as promising modalities applicable to congenital cardiac diagnosis. 7, 9 additionally, integrated 3d images from 3dra, Ct, and Mri overlaid onto live fluoroscopy are now being used for roadmaps to guide Chd diagnostic and interventional procedures. 5, 6, 10 the potential benefits of integrating 3d images into fluoroscopic procedures for Chd are many, including: (1) improved diagnostic and interventional efficacy, (2) reduced overall radiation exposure, (3) reduced contrast dose, and (4) reduced procedural time. 11-13 all of these are particularly advantageous in the pediatric population. parallel to this, 3d transesophageal echocardiography (3d-tee) is currently being applied to Chd catheterization procedures. this technology allows real-time anatomic visualization of soft tissue structures and catheter guidance within the beating heart.

No abstract