Ex vivo renal artery reconstruction for complex RABAs eliminates the risk of rupture, confers a benefit to hypertension, and preserves renal function with a satisfactory long-term patency.
Less invasive aortic valve operations through a partial sternotomy or minithoracotomy can be performed with conventional bioprostheses. 1,2 Totally endoscopic aortic valve replacement (TEAVR) has not previously been feasible, because the currently available designs of stented tissue valves do not allow them to fit through a trocar. The recent advent of sutureless bioprostheses, mounted on a compressible self-expanding nitinol stent, has made this possible. We report the first TEAVR procedures in 2 patients through conventional thoracoscopic trocars. FIGURE 1. A, Preoperative computed tomographic images of patient 2 demonstrate how to assess and apply the selection criteria. It is recommended to avoid patients with insufficient periaortic working space (<2 cm between the inferior margin of the sternum and the aortic anterior wall; top left). To keep a comfortable distance between the aortic clamp, the cardioplegia needle, and the aortotomy, and consequently safe placement of the aortic closing sutures, very short aortas should also be excluded (the central line of the ascending aorta should be longer than 5 cm; top right). Vertical aortas without physiologic curvature should be avoided; the central axis of the proximal aortic root (bottom left, red line), together with the operative axis of the third intercostal space (bottom left, blue line), should create an angle not exceeding 45 , to avoid any traction onto the margins of the aortotomy when instruments are inserted in the aortic root through the trocars. The last panel (bottom right) shows a 3-dimensional reconstruction of the computed tomographic scan. B, Patient 1's aortotomy can be seen on the screen. C, Intraoperative photograph of patient 2 shows operating field and trocar positioning. The main working trocar (20 mm) is in the second intercostal space, a second operative trocar (15 mm) is in the third, a percutaneous transthoracic aortic clamp is in the first, a 5-mm 30 optic is in the second (7 mm trocar), and a right pulmonary vein venting line and purse-string with carbon dioxide insufflation line are in the fifth (both with a 7 mm trocar). D, Patient 2 is shown on postoperative day 4.
It was recently submitted that the rupture risk of an ascending thoracic aortic aneurysm (ATAA) is strongly correlated with the aortic stiffness. To validate this assumption, we propose a non-invasive inverse method to identify the patient-specific local extensional stiffness of aortic walls based on gated CT scans. Using these images, the local strain distribution is reconstructed throughout the cardiac cycle. Subsequently, obtained strains are related to tensions, through local equilibrium equations, to estimate the local extensional stiffness at every position. We apply the approach on 11 patients who underwent a gated CT scan before surgical ATAA repair and whose ATAA tissue was tested after the surgical procedure to estimate the rupture risk criterion. We find a very good correlation between the rupture risk criterion and the local extensional stiffness. Finally it is shown that patients can be separated in two groups: a group of stiff and brittle ATAA with a rupture risk criterion above 0.9, and a group of relatively compliant ATAA with a rupture risk below 0.9. Although these results need to be repeated on larger cohorts to impact the clinical practice, they support the paradigm that local aortic stiffness is an important determinant of ATAA rupture risk.
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