Respiration-induced Deformations of the Superior Mesenteric and Renal Arteries in Patients with Abdominal Aortic Aneurysms

Abstract

Purpose This study was performed to quantify respiration-induced deformations of the superior mesenteric artery (SMA) and left and right renal arteries (LRA and RRA) in patients with small abdominal aortic aneurysms (AAA). Materials and Methods Sixteen men with AAAs (73±7 years) were imaged with contrast-enhanced magnetic resonance angiography during inspiratory and expiratory breath-holds. Centerline paths of the aorta and the visceral arteries were acquired by geometric modeling and segmentation techniques. Vessel translations, and changes in branching angle and curvature due to respiration were computed from the centerline paths. Results With expiration, the SMA, LRA, and RRA bifurcation points translated superiorly by 12.4±9.5, 14.5±8.8, 12.7±6.4 mm (P<0.001) and posteriorly by 2.2±2.7, 4.9±4.2, 5.6±3.9 mm (P<0.05), respectively, and the SMA translated rightward by 3.9±4.9 mm (P<0.01). With expiration, the SMA, LRA, and RRA angled upwards by 9.7±6.4°, 7.5±7.8°, and 4.9±5.3°, respectively (P<0.005). With expiration, the mean curvature increased by 0.02±0.01, 0.01±0.01, 0.01±0.01 mm−1 in the SMA, LRA, and RRA, respectively (P<0.05). For both inspiration and expiration, the RRA curvature was greater than in other vessels (P<0.025). Conclusions With expiration, the SMA, LRA, and RRA translated superiorly and posteriorly due to diaphragmatic motion, inducing upward angling of vessel branches and increase in curvature. In addition, the SMA exhibited rightward translation with expiration. The RRA was significantly more tortuous, but deformed less than the other vessels during respiration.

Three-Dimensional Modeling Analysis of Visceral Arteries and Kidneys during Respiration

“…The RRA was in contact with the IVC 20 to 34-mm distal to the aorta, explaining why the RRA translated significantly less than the LRA at the 30-mm point (P≤ 0.03) due to respiration. This evidence supports previous findings that the IVC’s contact with the RRA provides mechanical support [10,12]. Due to this combination of characteristics, the RRA translation within the proximal 30-mm of length appears to be less correlated to kidney translation as compared to the LRA.…”

“…Such endovascular techniques are effective at preserving target vessel patency initially, but longer-term studies have identified the potential for branch vessel stent-graft instability and renal compromise using either technique, potentially as a result of branch graft dislodgement, migration, or kinking [8–10]. These long-term limitations highlight the need to quantify in vivo visceral vessel geometry and deformation as a function of diaphragmatic excursion and respiratory-related displacement of the abdominal viscera [1,10–12]. …”

A Lagrangian cylindrical coordinate system for characterizing dynamic surface geometry of tubular anatomic structures

“…Several methods have been developed to model human vessels and quantify geometric curvature. Classic methods have employed 2D level set segmentation creating a set of orthogonal contours following vascular lumen, acquiring centerlines from the contours, and computing the curvature along the centerline [ 6 , 7 , 21 , 22 , 24 , 25 ]. Other available methods include 3D segmentation with growing seeds, acquiring centerline from inscribing spheres in lumenal surface, and computing the centerline curvature [ 11 , 15 ].…”

Tortuosity is the Significant Predictive Factor for Renal Branch Occlusion after Branched Endovascular Aortic Aneurysm Repair

“…Renal arteries become relatively straight during inspiration, but become more curved during expiration. 12 This cyclic bending exposes the bridging covered stents to mechanical stress. 12,13 In theory, the risk of stent failure can be minimized by avoiding long stents extending to the distal part of renal artery, where the arterial bending is greater than proximally.…”

“…12 This cyclic bending exposes the bridging covered stents to mechanical stress. 12,13 In theory, the risk of stent failure can be minimized by avoiding long stents extending to the distal part of renal artery, where the arterial bending is greater than proximally. However, the length of the covered stent in the renal artery was not a significant risk factor for occlusion.…”