RV Trabecular Complexity Fractal Analysis: Measuring Remodeling in PH
Right ventricular fractal dimension was a reproducible measure of remodeling in pulmonary hypertension, but it did not offer significant survival prediction compared with traditional markers.
The fractal dimension of right ventricular (RV) trabecular complexity was a reproducible marker of remodeling in patients with pulmonary hypertension (PH), according to a recent study published in Radiology.
This retrospective study used data from a previous study in which participants underwent baseline testing such as cardiac MRI, 6-minute walk distance, biventricular fraction dimension, volume, and function assessments. Participants were divided between individuals who had PH (n=256) and healthy control participants (n=256). RV fraction dimension associations with reproducibility, functional parameters, and survival predictions were compared between the groups.
Reproducibility of results between observers was good, with an intraclass correlation coefficient of 0.97. The global fractal dimension was higher in patients with PH than in healthy control participants in the right ventricle but lower in the left ventricle (P <.001 for both).
Additionally, global fractal dimension was weakly associated with a higher indexed RV end diastolic and end systolic volumes, heart rate, cardiac index, and lower indexed RV stroke volume and RV ejection fraction; however, RV global as well as maximum basal fractal dimensions were not significant univariable predictors of survival (P =.14 and P =.37, respectively).
The researchers wrote, “[Fractal dimension] is a reproducible measure of RV trabecular complexity on cardiac MR images, a marker of elevated afterload in patients with PH, and enables prediction of all-cause mortality, though the gains over traditional volumetric markers are not significant.”
Dawes T, Cai J, Quinlan M, et al. Fractal analysis of right ventricular trabeculae in pulmonary hypertension [published online June 5, 2018]. Radiology. doi:10.1148/radiol.2018172821