- [Show abstract] [Hide abstract] ABSTRACT: To describe the histological findings in the aortic wall 5 days after thoracic endovascular aortic repair (TEVAR) in a porcine model. Two overlapping stent-grafts were implanted in each of 6 juvenile pigs, covering the entire descending thoracic aorta (DTA). On the 5(th) postoperative day, tissue samples were taken from the DTA in each animal. Medial thickness and medial necrosis were quantified and compared to measurements from the aortas of 6 control animals. Significant medial thinning was observed in stent-covered regions in the test animals. At the proximal landing zone, aortic wall thickness changed from 1387±68 to 782±74 µm within the covered aortic segment (p = 0.028); at the distal landing site, the wall thickness was 365±67 µm within the stent and 501±57 µm distally (p = 0.028). In the overlap zone, the aortic wall measured 524±122 vs. 1053±77 µm in native controls (p = 0.004). Aortic thickness proximal to the graft did not differ from the proximal region of native aortas (1468±96 vs. 1513±80 µm, p = 0.423), but the aorta was significantly thinner distal to the stent (707±38 vs. 815±52 µm, p = 0.004). Laminar necrosis constituted 38%±7% of the media in the proximal landing zone, 54%±4% in the overlap zone, and 46%±13% in the distal landing zone. In this porcine model, significant medial thinning and necrosis of the stented aorta was observed. The findings suggest an early phase of vulnerability of the aortic wall, before scarring and adaptive changes have strengthened the residual aorta.
- [Show abstract] [Hide abstract] ABSTRACT: By using deep hypothermic circulatory arrest and non-deep hypothermic circulatory arrest approaches, we examined the impact of distal ischemia time and temperature on intra-abdominal reversible adverse outcomes and permanent adverse outcomes during descending thoracic aortic and thoracoabdominal aortic aneurysm operations. A retrospective review of all patients who underwent descending thoracic aortic and thoracoabdominal aortic aneurysm repair between January 2002 and December 2008 was undertaken, including relevant preoperative, intraoperative, and postoperative data, and followed by a propensity score-matched analysis. Of the total of 262 patients, 240 had data complete enough to permit analysis, and 90 were suitable for the propensity-matched study. Reversible adverse outcomes included renal failure, liver failure, and temporary hemodialysis. Permanent adverse outcomes included paraplegia, permanent hemodialysis, and 30-day mortality. Thirty-day mortality was 7.1% (17/240). Overall, reversible adverse outcomes developed in 40.8% of patients and permanent adverse outcomes developed in 10% of patients. The propensity score analysis identified statistically significant decreased odds of developing reversible adverse outcomes in patients undergoing deep hypothermic circulatory arrest (odds ratio, 0.32; confidence interval, 0.12-0.85). Specifically, significantly lower rates of acute renal failure (22% vs 46.4%, P = .03) and liver failure (17.8% vs 34.3%, P = .04) were observed in the deep hypothermic circulatory arrest group compared with the non-deep hypothermic circulatory arrest group. In addition, there were decreased odds of reversible adverse outcomes (odds ratio, 0.22; confidence interval, 0.06-0.79) developing in patients with a stage II elephant trunk procedure. During descending thoracic aortic and thoracoabdominal aortic aneurysm repairs, the use of deep hypothermic circulatory arrest results in improved postoperative adverse outcome rates compared with non-deep hypothermic circulatory arrest techniques. The development of reversible adverse outcomes is strongly associated with the development of permanent adverse outcomes.
- [Show abstract] [Hide abstract] ABSTRACT: In a porcine model, we investigated the impact of sudden stent graft occlusion of thoracic intercostal arteries after open lumbar segmental artery (SA) ligation. After randomization into two groups, 20 juvenile Yorkshire pigs (27.1±0.6 kg) underwent open lumbar SA sacrifice (T13-L5) followed by endovascular coverage of all thoracic SAs (T4-T12) at 32°C, either in a single operation (group 1) or in two stages separated by seven days (group 2). Collateral network pressure (CNP) was monitored by catheterization of the SA L1, and postoperative hind limb function was assessed using a modified Tarlov score. The CNP in group 1 decreased to 34% of baseline, whereas CNP after lumbar SA ligation in group 2 fell to 55% of baseline (74±2.4 to 25±3.6 mm Hg vs 74±4.5 to 41±5.5 mm Hg; p<0.0001). Subsequent thoracic stenting (group 2) led to another significant but milder drop (p=0.002 versus stage 1) from the restored CNP (71±4.2 to 54±4.9 mm Hg). Five of ten pigs in group 1 suffered paraplegia, in contrast to none in group 2 (median Tarlov score 6, vs 9; p=0.0031). Histopathologic analysis showed more severe ischemic damage to the lower thoracic (p=0.05) and lumbar spinal cord (p=0.002) in group 1. These results underline the potential of the staged approach in hybrid procedures. Furthermore they highlight the need for established adjuncts for preventing paraplegia in hybrid and pure stent-graft protocols in which sudden occlusion of multiple SAs occurs.
- [Show abstract] [Hide abstract] ABSTRACT: We describe the long-term results of aortic arch replacement using a trifurcated graft, including an assessment of survival, neurologic complications, and graft patency. A retrospective review was conducted on data from 206 consecutive patients (125 male; median age, 67 years; range, 20-87 years) who had a trifurcated graft used for aortic arch replacement between September 1999 and September 2009. Seventy-four patients (35.9%) had chronic dissection, 68 patients (33.0%) had atherosclerotic aneurysms, and 39 patients (18.9%) had degenerative disease. Ninety-one patients (44.2%) had undergone previous cardiac surgery. An elephant trunk was placed in 190 patients (92.2%) and completed in 101 patients (53.1%), with an interval of less than 365 days between stages in 94 of 101 patients. Hospital mortality was 6.8% (14/206). Adverse outcome (death/stroke within the first year postoperatively) occurred in 27.7% of patients (57/206; 50 deaths/7 strokes). Among 152 1-year survivors, the annual rates of transient ischemic attack and stroke were 0.85% and 1.1%, respectively. At 6 years, 75% of patients were still alive, compared with 92% in a matched New York State control population (P < .001). Follow-up computed tomography scans (189 studies in 176/206 patients [85.4%]) revealed 100% patency of the trifurcated graft limbs at a mean of 2.3 years. Aortic arch replacement using a trifurcated graft is highly durable, with excellent patency in the branch grafts, and is associated with a low incidence of cerebral embolization. However, the long-term outcome in these patients is compromised by extensive comorbidities.