Aortic root dilation in adult patients with Marfan syndrome: Does aortic root stiffness matter?

Abstract

Objective: Aortic root (AoR) size remains an imperfect predictor of rate of aortic dilation in Marfan syndrome (MFS). Indicators of vascular phenotype such as aortic stiffness have been proposed as additional predictors. In this study we assessed the rate of AoR dilation and stiffness in adult patients with MFS.

Methods: We performed a retrospective chart review. We included adult patients with MFS (aged 20-40 years) with at least 2 local echocardiograms 6 months apart (no aortic surgery in-between). A blinded observer analyzed the echocardiograms. AoR dilation rate and stiffness were calculated.

Results: Thirty-two patients (53% women; median age, 21.1; interquartile range [IQR], 19-24 years at first echocardiogram) were included. AoR dilation rate in the entire cohort was 0 to 8 mm/year (median, 0.465; IQR, 0.23-1.45 mm/year). Multiple linear regression analysis showed that baseline AoR stiffness was associated with AoR dilation rate (β = 0.0004; P < .001 for elastic modulus), whereas baseline age and baseline AoR dimension were not. Eighteen of these 32 patients (56%) eventually had AoR surgery (Sx) and 14 did not have surgery (NSx). At baseline, Sx and NSx patients were similar in age. AoR dimension was larger (Sx, 4.27 cm; IQR, 4.05-4.49 cm vs NSx, 3.73 cm; IQR, 3.37-4.09 cm; P = .011) and AoR stiffness was higher in Sx patients (beta stiffness index: median, 23.2; IQR, 17.8-28.6 vs median, 15.6; IQR, 11.6-19.7; P = .024). AoR dilation rate was greater in Sx patients, independent of baseline AoR dimension (1.63 ± 0.41 mm/year vs 0.38 ± 0.08 mm/year; P = .01).

Conclusions: Our results showed that AoR dilation rate varies among adult patients with MFS and is associated with baseline AoR stiffness, measured by echocardiography. Further studies are warranted to determine how aortic stiffness can be implemented clinically to refine management in patients with MFS.

Keywords: AoR, aortic root; EM, elastic modulus; MFS, Marfan syndrome; Marfan syndrome; NSx, no surgery; SI, stiffness index; Sx, Surgery; aortic root; dilation; stiffness.

Graphical abstract

Patients with Marfan syndrome with stiffer aorta have faster aortic root dilation.

Figure 1

Two-dimensional echocardiographic image demonstrating inner-edge-to-inner-edge measurement of aortic root dimension in systole.

Figure 2

Rates of aortic root dilation of the participants. Line slopes reflect the rate of change of aortic root dimension (millimeters/year) over a 1-year period for each patient. Echo, Echocardiogram; IQR, interquartile range.

Figure 3

A, Rate of aortic root dilation for patients with beta stiffness indices (BSIs) above and below the median at baseline (>median is stiffer). B, Rate of aortic root dilation for patients with an elastic modulus (EM) above and below the median at baseline (>median is stiffer). The upper and lower borders of the box represent the upper and lower quartiles. The middle horizontal line represents the median. The upper and lower whiskers represent the maximum and minimum values of nonoutliers. Extra dots represent outliers.

Figure 4

Aortic root dilates faster in patients with Marfan syndrome with stiffer aortas. The upper and lower borders of the box represent the upper and lower quartiles. The middle horizontal line represents the median. The upper and lower whiskers represent the maximum and minimum values of nonoutliers. Extra dots represent outliers. EM, Baseline elastic modulus; BSI, baseline beta stiffness index.