Reduced proximal aortic compliance and elevated wall shear stress after early repair of tetralogy of Fallot

Abstract

Objective: Patients with tetralogy of Fallot are at risk for late aortic complications due to progressive aortic root dilation and decreased aortic compliance. Early repair normalizes aortic dimensions by preadolescence. It is not known if early repair normalizes aortic wall histology and compliance or reduces late aortic complications. We used 4-dimensional flow magnetic resonance imaging to determine if children with tetralogy of Fallot repaired in infancy had normal aortic dimensions and to characterize the aortic wall hemodynamic state and luminal flow parameters in these patients.Methods: Comprehensive aortic analysis with 4-dimensional flow magnetic resonance imaging was performed in 18 patients with tetralogy of Fallot who were repaired in infancy and compared with 18 normal volunteers. Peak systolic and time-averaged wall shear stress, relative area change, and distensibility were evaluated in standardized aortic planes. Qualitative grade scale flow analysis with interactive pathline visualization was used to detect pathologic flow patterns.Results: Thoracic aortic dimensions did not differ between groups, and all tetralogy of Fallot aortas were in normal range. In the tetralogy of Fallot group, ascending and descending aortic relative area change and distensibility were significantly reduced, and both peak systolic and time-averaged wall shear stress were elevated throughout the aorta. Supra-physiologic systolic helical formations occurred in the ascending aorta of 14 patients with tetralogy of Fallot (78%) versus 0 controls.Conclusions: Despite early repair and normal aortic dimensions, preadolescents and adolescents with tetralogy of Fallot had elevated wall shear stress, increased stiffness, and pathologic systolic flow formations in the proximal aorta. Although early repair normalizes aortic dimensions in childhood, our findings suggest that patients with tetralogy of Fallot remain at risk for late aortic complications.

Increased Aortic Stiffness and Left Ventricular Dysfunction Exist After Truncus Arteriosus Repair

“…5,6 Aortopathy has been demonstrated by our group and others to be present within defined congenital heart disease pathologies, most notably conotruncal anomalies. 1,7,8 Proposed mechanisms for abnormal aortic biomechanical and structural properties include increased flow jet angles and resultant flow eccentricity. 9 Magnetic resonance imaging (MRI) has emerged as a preferred strategy for determining cardiovascular anatomy, blood flow velocities and volumes, regional and global ventricular function, and myocardial health.…”

Feasibility of Wave Intensity Analysis in Patients With Conotruncal Anomalies Before and After Pregnancy: New Physiological Insights?

“…Patients with congenital heart disease including CTA may present with dilatation of the thoracic aorta during their lifetime. Histological abnormalities of the aortic wall have been identified in patients with ToF and d-TGA as responsible for the early presentation of aorta dilation despite early surgical repair (10,12,14,15).…”

“…Wave intensity defined as dI (A) = dUdlnA differs from the definition of wave intensity dI (P) = dPdU by a difference in dimensions [wave intensity dI (P) has the units W/m 2 and dI (A) has the units m/s] (14,15). However, it can be shown that they differ only by a scaling factor, ρc 2 , where ρ = blood density (16).…”

The aorta in repaired tetralogy of Fallot: A potential source of late danger?

“…With this novel and innovative study, Schafer and colleagues 1 have turned a spotlight on the overlooked (presumptively healthy) left side of the heart in repaired tetralogy of Fallot (TOF). Although emphasis has been paid to the management of the right ventricular outflow tract in TOF, this report calls attention to the potentially hostile nature of the aorta in this disease.…”