Segmental Aortic Stiffness in Children and Young Adults with Connective Tissue Disorders: Relationships with Age, Aortic Size, Rate of Dilation and Surgical Root Replacement
Background—Aortic diameter is an imperfect predictor of aortic complications in connective tissue disorders (CTDs). Novel indicators of vascular phenotype severity such as aortic stiffness and vertebral tortuosity index (VTI) have been proposed. We assessed the relation between aortic stiffness by cardiac magnetic resonance imaging (CMR), surgical root replacement and rates of aortic root dilation in children and young adults with CTDs.
Methods and Results—Retrospective analysis of CMR data on children and young adults with a CTD was performed to derive aortic stiffness measures (strain, distensibility, and β stiffness index) at the aortic root, ascending aorta (AAO) and descending aorta (DAO). VTI was calculated as previously described. Rate of aortic root dilation prior to CMR was calculated as change in echocardiographic aortic root diameter z-score per year. In 83 CTD patients (median age 24 years, range 1-55, 17% under age 18 years; 60% male), AAO distensibility was reduced compared to published normative values: median z-score -1.93 (range -8.7 to 1.3, p<0.0001 vs. normals). Over a median follow-up period of 2.7 years, there were no aortic dissections or deaths but 16/83 (19%) patients underwent surgical aortic root replacement. In multivariable analysis, lower aortic root strain (p=0.05) and higher VTI (p=0.01) were independently associated with aortic root replacement. Lower AAO strain (p=0.02) was associated with a higher rate of aortic root dilation.
Conclusions—Higher aortic stiffness is associated with higher rates of surgical aortic replacement and aortic root dilation in children and young adults with CTDs.
- connective tissue disorder
- aortic stiffness
- cardiac magnetic resonance imaging
- aortic surgery
- Marfan syndrome
- aortic disease
- Received December 15, 2014.
- Revision received June 10, 2015.
- Accepted June 15, 2015.