Prosthetic aortic graft replacement of the ascending thoracic aorta alters biomechanics of the native descending aorta as assessed by transthoracic echocardiography

Abstract

The funders had no role in study design, data collection and greater wall thickness, and higher prevalence of calcific atherosclerotic plaque in the degenerative group (all p<0.05). In multivariate analysis, congenital/genetically associated AA etiology conferred a 4-fold increment in magnitude of augmented native descending aortic strain after proximal grafting (B = 4.19 [CI 1.6, 6.8]; p = 0.002) independent of age and descending aortic size. Conclusions Prosthetic graft replacement of the ascending aorta increases magnitude and rapidity of distal aortic distension. Graft effects are greatest with congenital or genetically associated AA, providing a potential mechanism for increased energy transmission to the native descending aorta and adverse post-surgical aortic remodeling.

Progressive Microstructural Deterioration Dictates Evolving Biomechanical Dysfunction in the Marfan Aorta

“…These findings are consistent with expectations based on prior comparisons of regional differences in elastic fiber deterioration ( 33 ) and wall mechanics ( 34 ) along the length of the Fbn1 mgR / mgR aorta. Of clinical importance, longitudinal studies in patients have revealed that the descending thoracic aorta presents with increasing aortopathy following surgical repair of the proximal aorta in Marfan patients ( 35 ). Although it is not known whether this increased risk arises because of changes in hemodynamic loading on the descending thoracic aorta following the surgical implantation of a stiff synthetic proximal graft or simply whether surgical extension of life-span allows a longer period for the descending segment to deteriorate, the importance of studying the descending aorta is nevertheless clear.…”

Descending aortic strain quantification by intra‐operative transesophageal echocardiography: Multimodality validation via cardiovascular magnetic resonance

“…Our findings extend upon prior studies which have demonstrated the utility of echo and CMR in assessing characterizing aortic physiology in surgical populations and predicting clinical outcomes in cardiovascular disease 9,15‐17 . For example, Rong et al demonstrated that surgical AA graft replacement increases immediate circumferential strain of the descending aorta, suggesting that surgical grafts augment energy transfer to the distal aorta and may contribute to progressive distal aortic dilation or dissection after surgery: Subsequent data demonstrated increased descending aortic strain to be sustained among ambulatory patients undergoing transthoracic echo prior to and following AA graft replacement 5 . Scarabello et al evaluated AA strain using CMR in a large diverse cohort and found that significant differences in age, gender, and cardiovascular disease independently affected AA strain 18,19 .…”

“…Consistent with previous literature by our group and others, 5,7‐9 the following global indices of aortic biomechanics were considered for both TEE and CMR analysis: Global circumferential aortic strain (GCS)—peak circumferential deformation of the aortic wall between systole and diastole (measured as the relative (%) difference between these two time points; [end‐systole−end‐diastole]/end‐diastole × 100). Pulse pressure–adjusted GCS—GCS normalized for pulse pressure (PP): (GCS/PP) 9 Time‐to‐peak (TTP) strain—calculated as time interval between initial LV systolic contraction (R wave) and maximal circumferential aortic strain. …”

“…Prior studies have shown global circumferential aortic strain (GCS) to be impaired in an array of pathologic conditions common among patients undergoing cardiothoracic surgery—including cohorts with aortic aneurysms, 1 valvular stenoses, 2 and obstructive coronary artery disease 3 . Prior research has shown GCS to be capable of discerning acute changes in aortic loading conditions—as evidenced by increased descending aortic strain immediately after prosthetic graft replacement of the ascending thoracic aorta 4,5 . As strain is influenced by both intrinsic vessel wall tissue properties and cardiovascular hemodynamics, it provides insight into aortic biomechanics not attainable via conventional parameters such as aortic size and flow velocity.…”

Clinical implications of the biomechanics of bicuspid aortic valve and bicuspid aortopathy

“…Strategies to identify which patients would benefit from surgery is critical since an operation is not without risks. Ascending aorta replacement grafts are stiff with altered geometry, which can lead to downstream descending aorta distention and aneurysm (86). Presently, prophylactic surgery for aortic dilatation is guided by aortic diameter and presence of risk factors that would predispose one to aortic complications (85).…”