Introduction: The compliance of the aorta serves an important function to reduce the impedance and workload for cardiac ejection. Stent grafts currently used for thoracic endovascular aortic repair (TEVAR) are orders of magnitude stiffer compared to the native aorta, yet the impact of this mismatch on cardiovascular function is unclear.
Methods: Patients without valvular or pulmonary disease undergoing TEVAR for thoracic aortic aneurysms (2013 - 2015) were selected. Data from computed tomography and echocardiography before TEVAR and at one year follow-up were analyzed. The impact of TEVAR on cardiac function was computationally assessed using patient-specific fluid structure interaction (FSI) simulations.
Results: Six patients (all female) were included, mean age was 81±4 years. Two patients were on antihypertensive drugs prior to TEVAR; this number increased to six after TEVAR. FSI computations revealed an increase in pulse pressure and decrease in cardiac output immediately following TEVAR if the effects of medication and autoregulation were excluded. At one year follow-up, a 33% increase in left ventricular mass index (67±13 g/m2 to 89±17 g/m2, P=0.047), a 41% increase in end-systolic left ventricular internal diameter (2.1±0.5 cm to 3.0±0.5 cm, P=0.001) and a 38% reduction in left ventricular fractional shortening (0.48±0.06 to 0.30±0.07, P=0.003) were observed as markers of adverse left ventricular remodeling, with no changes in cardiac output.
Conclusions: Replacement of the native aorta with thoracic endografts creates a stiffness mismatch that increases pulse pressure and left ventricular afterload, inducing adverse cardiac remodeling. New endograft designs should consider the impact of aortic stiffening, particularly with the emerging role of TEVAR in more proximal aortic segments and younger patient populations.
Figure 1: FU = follow-up, LV = left ventricular, LVIDs = left ventricular internal diameter in systole, FS = fractional shortening