Johannes Scheumann

Staged Approach Prevents Spinal Cord Injury in Hybrid Surgical-Endovascular Thoracoabdominal Aortic Aneurysm Repair: An Experimental Model

BACKGROUND In a porcine model, we investigated the impact of sudden stent graft occlusion of thoracic intercostal arteries after open lumbar segmental artery (SA) ligation. METHODS 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. RESULTS 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. CONCLUSIONS 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.

Long-term outcome after aortic arch replacement with a trifurcated graft

OBJECTIVE We describe the long-term results of aortic arch replacement using a trifurcated graft, including an assessment of survival, neurologic complications, and graft patency. METHODS 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. RESULTS 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. CONCLUSIONS 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.

Staged approach for spinal cord protection in hybrid thoracoabdominal aortic aneurysm repair

At present, there are three available options for surgical thoracoabdominal aortic aneurysm (TAAA) repair: conventional open surgery, total endovascular repair, and a hybrid approach, involving conventional surgical and endovascular techniques. Each modality has a different risk/benefit profile, requiring careful patient selection. Spinal cord injury (SCI) due to compromised blood supply following extensive segmental artery (SA) sacrifice is a daunting complication observed with all three approaches. A thorough understanding of the response of the spinal cord vasculature to SA sacrifice is essential to minimize the incidence of SCI after open or endovascular repair of TAAA. For over a decade, perioperative spinal cord protection during TAAA repair has been investigated in Dr. Griepp’s laboratory at The Mount Sinai Hospital in New York. Clinical and experimental work have provided insight into the anatomy of the extensive vascular network surrounding the spinal cord, and its dynamic response to SA sacrifice. This new understanding of spinal cord perfusion has been termed the Collateral Network Concept (CNC) (1).

Technical details making aortic arch replacement a safe procedure using the Thoraflex™ Hybrid prosthesis

Summary The development of new devices to improve treatment and to explore new indications that have not yet been adequately addressed is a natural consequence of the clinical demand for solutions to as yet unmet needs. The frozen elephant trunk technique was one of the major steps within the last 15 years to improve on existing treatments as well as to explore new indications. The goal of this article is to provide technical details about advances in implantation techniques for the treatment of acute and chronic thoracic aortic pathological conditions.

Early Histological Changes in the Porcine Aortic Media After Thoracic Stent-Graft Implantation

Purpose To describe the histological findings in the aortic wall 5 days after thoracic endovascular aortic repair (TEVAR) in a porcine model. Methods Two overlapping stent-grafts were implanted in each of 6 juvenile pigs, covering the entire descending thoracic aorta (DTA). On the 5th 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. Results 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. Conclusion 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.

The frozen elephant trunk technique for the treatment of acute complicated Type B aortic dissection

OBJECTIVES Our goal was to report our preliminary results in patients with acute complicated Type B aortic dissection without a suitable landing zone for primary thoracic endovascular aortic repair who were treated with the frozen elephant trunk (FET) technique. METHODS Within a 25-month period, 14 patients with acute complicated Type B aortic dissection underwent surgical repair using the FET technique. The reasons to perform the FET procedure were an ectatic ascending aorta/arch in 6 patients and the lack of an adequate landing zone in 8 patients. RESULTS No deaths were observed. A non-disabling stroke occurred in 2 patients. Symptomatic spinal cord injury was not observed. The closure of the primary entry tear was successfully achieved in all patients. In 3 patients, a secondary distal thoracic endovascular aortic repair extension was performed during the same hospital stay. The median follow-up period was 6 ± 5 months. CONCLUSIONS The FET technique is an attractive method for the repair of acute complicated Type B aortic dissection without a suitable landing zone for primary thoracic endovascular aortic repair. It should be considered as an alternative in patients who are at high risk for retrograde Type A aortic dissection, in patients with an unfavourable anatomy or in patients with connective tissue disease.

Leitlinien Aortenerkrankungen der European Society of Cardiology

ZusammenfassungIn der Aortenmedizin sind noch viele Fragen offen. Leitlinien helfen uns dabei, die bestmögliche Entscheidung zur Therapie einer Aortenerkrankung zu treffen. Dieser Übersichtsbeitrag zu den Leitlinien der European Society of Cardiology (ESC) über Aortenerkankungen fasst die aktuellen Kernempfehlungen bezüglich der Behandlung der Aortenpathologien zusammen. Mehr Informationen zu seltenen Erkrankungen wie Aortentumoren, Aortitis und seltene genetische Aortenerkankungen sind in den Leitlinien ausführlich dargestellt.AbstractIn medicine of the aorta many questions are still unanswered. Guidelines help us to make the best possible decision for treatment of aortic diseases. This review article on the guidelines of the European Society of Cardiology (ESC) on aortic diseases summarizes the current core recommendations with respect to the treatment of aortic pathologies. More information on rare diseases, such as tumors of the aorta, aortitis and rare genetic diseases of the aorta are comprehensively described in the guidelines.

Endovascular treatment of acute Type A aortic dissection—the Endo Bentall approach

Outcome after classical surgical repair of acute Type A aortic dissection has steadily improved over the years and several modifications in cannulation and perfusion added to this achievement. However, subgroups remain where results of classical surgical repair still have room for improvement, particularly patients with severe preoperative malperfusion as well as elderly patients with a limited physiological reserve. So far, only small case series or case reports have been published on the endovascular treatment of dissected ascending aortas. However, a tube alone is not sufficient to fix the entire complex underlying problem in the vast majority of patients with acute Type A aortic dissection. In addition, these published reports are either due to a favorable anatomy or due to very localized disease processes, which are the exception and not the rule. The concept of an endovascular valve-carrying conduit may significantly increase the number of patients suitable for endovascular therapy and it may soon be common practice.

True-lumen and false-lumen diameter changes in the downstream aorta after frozen elephant trunk implantation

OBJECTIVES To evaluate early and mid-term clinical outcomes and to assess the potential of the frozen elephant trunk technique to induce remodelling of downstream aortic segments in acute and chronic thoracic aortic dissections. METHODS Over a 4-year period, 65 patients (48 men, aged 61 ± 12 years) underwent total aortic arch replacement using the frozen elephant trunk technique for acute (n = 31) and chronic (n = 34) thoracic aortic dissections at our institution. We assessed diameter changes at 3 levels: the L1 segment at the stent graft level; the L2 segment at the thoraco-abdominal transition level and the L3 segment at the coeliac trunk level. True-lumen (TL) and false-lumen (FL) diameter changes were assessed at each level. RESULTS Fifty-six percent of patients had already undergone previous aortic or cardiac surgery. In-hospital mortality was 6%. Symptomatic spinal cord injury was not observed in this series. During a mean follow-up of 12 ± 12 months, late death was observed in 6% of patients. Aortic reinterventions in downstream aortic segments were performed in 28% at a mean of 394 ± 385 days. TL expansion and FL shrinkage were measured in all segments and were observed at each level. This effect was the most pronounced at the level of the stent graft in patients with chronic aortic dissection, TL diameter increased from 15 ± 17 mm before surgery to 28 ± 2 mm (P = 0.001) after 2 years, and the FL diameter decreased from 40 ± 11 mm before surgery to 32 ± 17 mm (P = 0.026). CONCLUSIONS The frozen elephant trunk technique is associated with an excellent clinical outcome in a complex cohort of patients, and also effectively induces remodelling in downstream aortic segments in acute and chronic thoracic aortic dissections. The need for secondary interventions in downstream segments, which mainly depends on the extent of the underlying disease process, remains substantial. Further studies are required to assess the long-term outcome of this approach.

New insights into spinal cord ischaemia after thoracic aortic procedures: the importance of the number of anterior radiculomedullary arteries for surgical outcome

OBJECTIVES Anterior radiculomedullary arteries (ARMAs) link dorsal segmental arteries and the intraspinal compartment of the spinal collateral network. The number of thoracic ARMA is highly variable from one person to another. The impact of the number of ARMAs on spinal cord perfusion during thoracic aortic procedures is unknown. We investigated the influence of the number of thoracic ARMAs on spinal cord perfusion in an aortic surgical large animal model. METHODS Twenty-six pigs were included (20 treatment animals, 6 sham animals, weight 34 ± 3 kg). The animals underwent ligation of the left subclavian artery and the thoracic segmental arteries via a left lateral thoracotomy with normothermia. After sacrifice, complete body perfusion with coloured cast resin was performed and the number of thoracic ARMAs was documented at autopsy. End points were spinal cord perfusion pressure, cerebrospinal fluid pressure, spinal cord blood flow (microspheres) and neurological outcome. Observation time was 3 h post-ligation. RESULTS The numbers of thoracic ARMAs ranged between 3 (n = 1) and 13 (n = 1). The mean number was 8. Animals were grouped according to number of thoracic ARMA: 6-7 (5 animals), 8-10 (8 animals) and 11-13 (5 animals). A large number of thoracic ARMAs was linked to (i) a lower drop in spinal cord blood flow from baseline to post-clamp, (ii) the presence and increased magnitude of hyperaemia evident 3 h post-clamp (P < 0.001) and (iii) the presence of early hyperaemia starting immediately post-clamp in animals with 11 or more ARMA (P < 0.001). CONCLUSIONS We showed that a large number of thoracic ARMA protects against spinal cord injury during descending aortic surgical procedures.1.