Thorac Cardiovasc Surg 2016; 64 - ePP53
DOI: 10.1055/s-0036-1571919

Serial Flow Sensitive MRI in Pediatric Patients with Marfan Syndrome for Early Risk Stratification of Progressive Aortic Disease

K. Gottfried 1, D. Hirtler 1, J. Romberg 1, B. Stiller 1, J. Geiger 2
  • 1Universitäts-Herzzentrum Freiburg Bad Krozingen, Klinik für Angeborene Herzfehler und Pädiatrische Kardiologie, Freiburg, Germany
  • 2University Children's Hospital Zurich, Department of Radiology, Zürich, Switzerland

Objectives: 4D flow MRI was performed to analyze hemodynamics in patients with Marfan syndrome (MFS) to find suitable risk factors for early identification of high or low risk patients for cardiovascular complications.

Methods: Flow sensitive 4D MRI of the thoracic aorta was performed twice (t1and t2) in 19 pediatric patients with MFS (mean age at t1 12.7years, t2 16.2years). After visualization of aortic flow patterns by 3D particle traces, quantitative and qualitative analysis of the hemodynamics was performed. Secondary flow patterns (helix and vortex flow) in the ascending aorta, aortic arch, and descending aorta were graded in three categories (blinded reading, 2 observers). Regional time-averaged absolute wall shear stress (WSS), peak flow velocity, oscillatory shear index (OSI) were investigated particularly at eight sites.

Results: Aortic diameters decreased related to the patients' body surface area (aortic sinus: t1 20.9 ± 5.6mm/m2, t2 18.9 ± 4.0mm/m2, p = 0.005). The incidence of secondary flow patterns (figure) increased non-significantly. Peak flow velocity (t1 1.19 ± 0.17m/s, t2 1.09 ± 0.21m/s, p = < 0.001) and WSS (t1 0.38 ± 0.09N/m2, t2 0.24 ± 0.08N/m2, p< 0.001) decreased, and OSI (t1 9.11 ± 5.44%, t2 14.71 ± 6.59%, p< 0.001) increased significantly. A subgroup analysis by z-scores demonstrated higher WSS and lower OSI in patients with enlarged diameters. Patients with normal z-scores showed lower WSS and higher OSI.

Fig. 1 [Vortex flow in MFS patient (left t1, middle t2)].

Conclusion: This study revealed no linear progression toward enlarged diameters in MFS patients. This could be explained by the accelerated length growth rate during puberty and the current medication. No significant correlations were found between WSS, OSI, flow patterns and aortic diameters. 4D flow MRI is a valuable tool to simultaneously analyze aortic diameters, flow and wall parameters for the follow-up of MFS patients.