Comparison Study of the Effect of Aliskiren Versus Negative Controls on Aortic Stiffness in Patients With Marfan Syndrome Under Treatment With Atenolol

Marfan syndrome (MFS) is an inherited disorder of connective tissue with morbidity and mortality from aortic dilatation and dissection. The current standard of care is beta-blocker (BB) treatment and therapeutic target is heart rate. The degree of aortic dilatation and response to BB vary in adults with MFS. However, aortic stiffness is often present, and can be a predictor of aortic dilatation and cardiovascular complications. Aortic stiffness is a logical therapeutic target in adults with MFS.

Transforming growth factor beta(TGF-beta) mediates disease pathogenesis in MFS and contributes to aortic stiffness. Cross-talk between TGF-beta system and renin-angiotensin system (RAS) has been demonstrated. The angiotensin receptor blocker (ARB), losartan, inhibits TGF-beta activity and reverses aortic wall pathology in a Marfan mouse model. In a small cohort study, the use of ARB therapy (losartan or irbesartan) significantly slowed the rate of progressive aortic dilatation in patients with MFS, after BB therapy had failed to prevent aortic root dilatation. In another study, angiotensin converting enzyme inhibitor, perindopril, reduced both aortic stiffness and aortic root diameter in patients with MFS taking standard BB therapy. Renin inhibitor, aliskiren, has not been studied to reduce aortic stiffness and attenuate aortic dilatation in patients with MFS.

This trial is a randomized, open-label trial of 32 patients with Marfan syndrome, treated with 6 months of aliskiren vs. negative controls in patients with MFS under atenolol treatment. MRI for aortic pulsed wave velocity (PWV) and distensibility, measurements of central BP (CBP) and augmentation index (AIx) will be performed at the beginning and end of treatment. A blood drawn for serum markers of TGF-beta, extracellular matrix turnover and inflammation will also be performed at 0 and 6 months. We plan to determine whether aliskiren decreases aortic stiffness significantly more than negative controls in patients with MFS under atenolol treatment.