Right ventricular fractal dimension was higher in pulmonary hypertension patients but did not predict survival independently of conventional RV remodeling parameters (HR 1.179; 95% CI 0.871-1.596; P=.29).
Cohort (n=512)
Does right ventricular fractal dimension measured by cardiac MRI predict survival independently of conventional remodeling parameters in patients with pulmonary hypertension?
Fractal analysis of RV trabeculae is a reproducible imaging marker associated with pulmonary hypertension severity but does not provide independent prognostic value for survival over standard RV remodeling metrics.
Effect estimate: HR 1.179 (95% CI 0.871-1.596)
p-value: p=.29
Purpose To measure right ventricular (RV) trabecular complexity by its fractal dimension (FD) in healthy subjects and patients with pulmonary hypertension (PH) and to assess its relationship with hemodynamic and functional parameters and future cardiovascular events. Materials and Methods This retrospective study used data acquired from May 2004 to October 2013 in 256 patients with newly diagnosed PH who underwent cardiac MRI, right-sided heart catheterization, and 6-minute walk distance testing, with median follow-up of 4.0 years. A total of 256 healthy control subjects underwent cardiac MRI only. Biventricular FD, volumes, and function were assessed on short-axis cine images. Reproducibility was assessed with the intraclass correlation coefficient, correlation between variables was assessed with the Pearson correlation test, and mortality prediction was compared by using uni- and multivariable Cox regression analyses. Results RV FD reproducibility had an intraclass correlation coefficient of 0.97 (95% confidence interval CI: 0.96, 0.98). RV FD was higher in patients with PH (median, 1.310; interquartile range IQR, 1.281-1.341) than in healthy subjects (median, 1.264; IQR, 1.242-1.295; P < .001), with the greatest difference near the apex. RV FD was associated with pulmonary vascular resistance (r = 0.30, P < .001). At univariable Cox regression analysis, RV FD was a significant predictor of death (hazard ratio HR, 1.256; 95% CI: 1.011, 1.560; P = .04); however, at multivariable analysis, RV FD did not enable prediction of survival independently of conventional parameters of RV remodeling (HR, 1.179; 95% CI: 0.871, 1.596; P = .29). Conclusion Fractal analysis of RV trabecular complexity is a highly reproducible measure of remodeling in patients with PH that is associated with afterload, although the gain in survival prediction over traditional markers is not significant. Published under a CC BY 4.0 license. Online supplemental material is available for this article.
Dawes et al. (2018) conducted a cohort in Pulmonary hypertension (n=512). Right ventricular fractal dimension (RV FD) vs. Conventional parameters of RV remodeling was evaluated on Death (HR 1.179, 95% CI 0.871-1.596, p=.29). Right ventricular fractal dimension was higher in pulmonary hypertension patients but did not predict survival independently of conventional RV remodeling parameters (HR 1.179; 95% CI 0.871-1.596; P=.29).