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  • 1
    Abstract: RATIONALE AND OBJECTIVES: To evaluate whether dynamic computed tomography (CT)-imaging can provide functional vessel information in patients with chronic aortic dissection type Stanford-B (ADB). MATERIALS AND METHODS: In 32 patients, ECG-gated CT-angiography images were obtained. Cross-sectional area change and wall distensibility were investigated by semiautomatic vessel area segmentation at the end of aortic arch. Significance of distensibility differences was tested with regard to the aortic diameter, and the oscillation of the intimal flap was analyzed. RESULTS: The aorta could be segmented successfully in all patients. These were separated into three subgroups: (A) 6 patients with an aortic diameter 〈4 cm and without a visible intimal flap, (B) 9 patients with an aortic diameter 〈4 cm, and (C) 17 individuals with an aortic diameter 〉 or = 4 cm; (B) and (C) having a visible intimal flap. Differences in distensibility between the subgroups were not significant. Overall mean distensibility was D(tot)=(1.3+/-0.6) x 10(-5) Pa(-1). Analysis of intimal flap oscillation showed a pulsatile short axis diameter decrease of the true lumen of up to 29%. CONCLUSION: Dynamic, ECG-gated CT-angiography can demonstrate pulsatile changes in aortic area and a highly variable motion of the intimal flap. Aortic distensibility appears independent of diameter or presence of a intimal flap. Follow-up studies may show correlation with possible complications.
    Type of Publication: Journal article published
    PubMed ID: 18678452
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  • 2
    Keywords: DISEASE ; REPAIR ; CURVATURE ; stent-graft ; ANEURYSMS
    Abstract: PURPOSE: The purpose of this study was to identify morphologic factors affecting type I endoleak formation and bird-beak configuration after thoracic endovascular aortic repair (TEVAR). METHODS: Computed tomography (CT) data of 57 patients (40 males; median age, 66 years) undergoing TEVAR for thoracic aortic aneurysm (34 TAA, 19 TAAA) or penetrating aortic ulcer (n = 4) between 2001 and 2010 were retrospectively reviewed. In 28 patients, the Gore TAG(R) stent-graft was used, followed by the Medtronic Valiant(R) in 16 cases, the Medtronic Talent(R) in 8, and the Cook Zenith(R) in 5 cases. Proximal landing zone (PLZ) was in zone 1 in 13, zone 2 in 13, zone 3 in 23, and zone 4 in 8 patients. In 14 patients (25 %), the procedure was urgent or emergent. In each case, pre- and postoperative CT angiography was analyzed using a dedicated image processing workstation and complimentary in-house developed software based on a 3D cylindrical intensity model to calculate aortic arch angulation and conicity of the landing zones (LZ). RESULTS: Primary type Ia endoleak rate was 12 % (7/57) and subsequent re-intervention rate was 86 % (6/7). Left subclavian artery (LSA) coverage (p = 0.036) and conicity of the PLZ (5.9 vs. 2.6 mm; p = 0.016) were significantly associated with an increased type Ia endoleak rate. Bird-beak configuration was observed in 16 patients (28 %) and was associated with a smaller radius of the aortic arch curvature (42 vs. 65 mm; p = 0.049). Type Ia endoleak was not associated with a bird-beak configuration (p = 0.388). Primary type Ib endoleak rate was 7 % (4/57) and subsequent re-intervention rate was 100 %. Conicity of the distal LZ was associated with an increased type Ib endoleak rate (8.3 vs. 2.6 mm; p = 0.038). CONCLUSIONS: CT-based 3D aortic morphometry helps to identify risk factors of type I endoleak formation and bird-beak configuration during TEVAR. These factors were LSA coverage and conicity within the landing zones for type I endoleak formation and steep aortic angulation for bird-beak configuration.
    Type of Publication: Journal article published
    PubMed ID: 25702140
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  • 3
    Keywords: ADAMKIEWICZ ARTERY, AGE, analysis, aneurysm, ANEURYSM REPAIR, ANEURYSMS, ANGIOGRAPHY, Aorta, artery
    Abstract: Purpose: To study the visualization of spinal cord feeding arteries in patients with complex thoracic aortic pathology undergoing endovascular aortic repair (EVAR) using an optimized protocol for multislice computed tomographic angiography (MSCTA). Methods: Eighteen consecutive patients (13 men; mean age 63 years, range 45-79) with aortic type B dissections (n=5), chronic expanding aortic dissections (n=5), thoracic aortic aneurysms (n=6), or penetrating aortic ulcers (n=2) underwent 16-slice CTA before and after (mean interval 9 days) EVAR. Pulse rate and neurological status were documented. Quantitative density measurements were taken at regions of interest (ROI) in the ascending thoracic aorta and at the level of the diaphragm. Two experienced radiologists qualitatively assessed the posterior intercostal arteries (PIA; fully visible, partially visible, non-visible), dorsal branches (DB; visible/non-visible), and artery of Adamkiewicz (AKA; visible/nonvisible) on multiplanar reformations and maximum intensity projection reconstructions. Results: MSCTA was performed successfully in 17/18 patients before and after EVAR (1 patient was excluded after EVAR owing to rising creatinine levels). Before EVAR, MSCTA revealed 197/203 PIAs within the stented area, of which 179 were fully and 18 partially visible. No significant (p=0.37) difference was noted for overall PIA detection within the stented area on post-EVAR MSCTA (185/203 PIA), although only 124 were fully and 61 partially visible. Similar results were obtained for DB visualization. The AKA were seen in 10/17 patients pre EVAR and 9/17 post EVAR. In 2 patients, the AKA was localized within the stented aortic segment. ROI analysis revealed contrast densities of 427+/-89 HU and 398 +/- 84 HU on pre- and post-EVAR MSCTA, respectively. No neurological events were observed. Conclusion: The majority of posterior intercostal arteries and dorsal branches remain open after EVAR due to retrograde perfusion. High-resolution MSCTA permits accurate pre- and post-EVAR visualization of spinal cord feeding arteries in patients with thoracic aortic pathology
    Type of Publication: Journal article published
    PubMed ID: 17924729
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  • 4
    Abstract: The aim of the study was to describe the clinical outcome of pararenal aortic aneurysm (PAAA) and type IV thoracoabdominal aneurysm (TAAA) repair, with special consideration placed on disease-related complications and midterm follow-up. Data were collected retrospectively between 1997 and 2004 for patients with PAAA or type IV TAAA repair. Comorbidities, operative details, and early and late outcome were analyzed to predict disease-related complications. During the study period, 63 patients (33 PAAAs, 30 type IV TAAAs) underwent aortic repair. The 30-day mortality rate of 7.9% was acceptable for complex aortic entities compared with other series. The morbidity for cardiac events was 3.2%, for pulmonary complications 17.5%, and the need for reoperation was 14.3%. With regard to disease-related complications, two patients (3.2%) required dialysis and one patient (1.6%) developed paraplegia (spinal cord ischemia) after type IV TAAA repair. Complex aortic repair for PAAAs and type IV TAAAs showed acceptable perioperative mortality, morbidity, and midterm survival rates. Patients with type IV TAAAs suffered more major complications, such as postoperative dialysis or spinal cord ischemia
    Type of Publication: Journal article published
    PubMed ID: 19476744
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  • 5
    Abstract: Objective: This retrospective single-center study analyzed long-term results after LifePath (Edwards Lifesciences LLC, Irvine, Calif) endoprosthesis implantation for abdominal aortic aneurysm (AAA), primarily focusing on the wire form fracture issue and consecutive endoleak rate. Methods: Between 1999 and 2004, all consecutive patients with LifePath AAA devices in our institution were included in the retrospective analysis. All patients had computed tomography angiography (CTA) imaging preoperatively and image postprocessing. The follow-up using CTA imaging specifically addressed material fatigue (wire form fractures) resulting in migrations and type I endoleaks. Results: During the 6-year study period, which included the 1-year withdrawal and redesign of the device, 51 patients were treated with LifePath AAA endografts. The 30-day mortality was 0%. The perioperative 30-day morbidity was 9.8%. One patient required a primary conversion due to misdeployment of the iliac limbs within the graft main body. The primary endoleak rate was 20.56% (type I, 2%; type II, 19.6%). During the mean follow-up of 40.7 months, 12 patients died, six were lost to follow-up, and 32 underwent subsequent CTA imaging. Eight patients (25%) demonstrated a proximal type I endoleak, seven (22%) had a type II endoleak, and three had a type III endoleak (9%). In nine patients (28.1%), wire form fractures could be detected at image postprocessing. Four patients required a secondary conversion due to endoleak and aneurysm growth (2 type I endoleaks and 2 type III endoleaks). Conclusion: Wire form fracture is the major structural problem in the LifePath balloon-expandable endograft device, resulting in a significant endoleak rate. We must caution those patients with a LifePath device in-situ that careful follow-up must be performed due to material fatigue and they should consider secondary conversion. (J Vasc Surg 2009;50:479-85.)
    Type of Publication: Journal article published
    PubMed ID: 19560311
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  • 6
    Abstract: We report a case with spinal cord ischemia and consecutive paraplegia following spontaneous isolated abdominal aortic dissection (IAAD). A 63-year-old female was admitted to the surgical emergency room with severe lumbar back pain and accompanying paresthesia of both legs. Contrast enhanced computed tomograpy (CT) of the abdomen showed an infrarenal IAAD in a normal size aorta with patent lumbar arteries. It was assumed that a surgical or interventional approach would not be helpful to improve spinal cord perfusion. Therefore, non operative therapy consisted of lowering blood pressure to prevent further dissection. The patient developed an anterior spinal artery syndrome with permanent paraplegia. Thus, blood pressure was raised for optimal spinal cord perfusion. To lower the spinal pressure, cerebrospinal fluid drainage was attempted. A three month follow-up CT scan showed spontaneous remodelling of the aorta. The neurological deficit persisted. IAAD is a rare differential diagnosis of lumbar back pain and can be associated with paraplegia as the leading symptom. Individualized treatment is indicated. Surgical treatment options concerning paraplegia are limited
    Type of Publication: Journal article published
    PubMed ID: 19736638
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  • 7
    Keywords: AGE ; ANGIOPLASTY ; aneurysm ; Aorta ; ANEURYSMS ; aortic dissection ; Aortic pathologies ; thoracic
    Abstract: Since its introduction by Dake et al., more than 20 years ago, thoracic endovascular aortic repair (TEVAR) has been used with increasing frequency for a variety of different pathologies of the thoracic aorta. Although long-term data are still missing, TEVAR is well-established and has meanwhile replaced conventional open repair (OR) as the first treatment option in many vascular centers. This evolution is based on a minimal invasive approach associated with a potentially lower morbidity and mortality rate. Nevertheless, TEVAR bares several procedure specific complications (e.g. endoleak, stent-graft migration, material fatigue) and technical pitfalls which must be kept in mind while dealing with this treatment option. The aim of this paper was, therefore, to present the lessons learned in I I years with thoracic endografting for different thoracic aortic pathologies focusing on applicability, results and device related problems. Over a period between January 1997 and September 2008 a total of 355 thoracic aortic stent-grafts were implanted in 221 patients (159 males, mean age 62 years), 59% under emergency conditions. Indications included patients with atherosclerotic and post-traumatic aneurysms, aortic dissections, aortobronchial fistulas, and traumatic ruptures. Besides the morphological classification of thoracic aortic lesions, preoperative modern 3-D imaging for adequate procedure planning, current devices and their specific aspects during placement will be discussed. Furthermore, our own experience and results in selected indications will be presented. Thoracic endovascular reconstruction appears to be a safe and effective alternative to OR for many patients with thoracic aortic diseases, especially in emergencies. Prospective trials for individual diseases will be necessary to define its ultimate role
    Type of Publication: Journal article published
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  • 8
    Keywords: ANGIOGRAPHY ; ORIGIN ; RENAL-ARTERIES ; DISSECTIONS ; REPLACEMENT ; ATRIAL-FIBRILLATION ; BRANCHED STENT-GRAFT ; ANEURYSMS ; CTA
    Abstract: PURPOSE: To evaluate whether quantitative characterization of aortic arch geometry including its branches is feasible based on in vivo computed tomography (CT) angiography and magnetic resonance (MR) angiography data in healthy and diseased aortic arches. MATERIALS AND METHODS: Ten healthy volunteers, 10 patients with abdominal aortic disease, and 10 patients with aortic arch disease underwent MR angiography (10 volunteers) or CT angiography (20 patients). Commercial software was used for individual segmentation of supraaortic arteries. In-house software was developed for segmentation of aortic arch landmarks based on standardized multiplanar reformations (MPRs) and for subsequent aortic arch mapping. RESULTS: Supraaortic arteries and aortic arch landmarks were successfully segmented in all 30 subjects for CT angiography and MR angiography data. Significant tapering within the first centimeter was observed in all supraaortic arteries (P 〈 .001). The three supraaortic arteries showed significantly different vessel diameters and areas (P 〈 .001). The software developed in-house allowed detailed aortic arch mapping with quantitative definitions of the positional relationships between each supraaortic artery and the aorta. Distances between supraaortic arteries were less than 5 mm in 77.6% (mean 4.1 mm +/- 3.8). The brachiocephalic trunk tended to be positioned on the right side of the aortic arch, and the left subclavian and left common carotid arteries tended to be positioned on the left side of the aortic arch. CONCLUSIONS: The feasibility and application of a postprocessing method allowing quantification of geometry of supraaortic arteries and aortic arch mapping were successfully demonstrated. Validation and evaluation of clinical implications are warranted
    Type of Publication: Journal article published
    PubMed ID: 21459612
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  • 9
    Abstract: Computational fluid dynamics, which uses numeric methods and algorithms for the simulation of blood flow by solving the Navier-Stokes equations on computational meshes, is enhancing the understanding of disease progression in type III aortic dissections. To illustrate this, we examined the changes in patient-derived geometries of aortic dissections, which showed progressive false lumen aneurysmal dilatation (26% diameter increase) during follow-up. Total pressure was decreased by 29% during systole and by 34% during retrograde flow. At the site of the highest false lumen dilatation, the temporal average of total pressure decreased from 45 to 22 Pa, and maximal average wall shear stress decreased from 0.9 to 0.4 Pa. These first results in the study of disease progression of type III DeBakey aortic dissection with computational fluid dynamics are encouraging.
    Type of Publication: Journal article published
    PubMed ID: 22579075
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  • 10
    Keywords: AGE, aneurysm, ANEURYSMS, ANGIOGRAPHY, COMPLICATIONS, connective tissue disease, DEATH, DEATHS, DISE
    Abstract: Purpose: To present midterm results after thoracic endovascular aortic repair (TEVAR) in patients with connective tissue diseases focusing on secondary endoleaks and reintervention due to disease progression. Methods: Between January 1997 and January 2007, 167 patients received 241 thoracic aortic stent-grafts. Eight patients (6 men; median age 48 years, range 32-67) with connective tissue diseases (6 Marfan and 2 Ehlers-Danlos syndrome) treated with stent-graft repair were retrospectively analyzed at a median follow-up of 31 months (range 3-79). Surveillance included postoperative computed tomographic angiography and/or magnetic resonance imaging exams prior to discharge, at 3, 6, and 12 months, and yearly thereafter. Results: Technical success of endovascular placement was 88% due to 1 primary type I endoleak. There were no perioperative deaths, and there have been no conversions to open surgery so far. Perioperative complications occurred in 2 (25%) of the 8 patients. Endoleaks were observed in 3 patients (primary type I, secondary type I, and type II). The reintervention rate was 38%. Progression of disease resulting in de novo aneurysms or aortic expansion occurred in 4 (50%) patients. Seven (88%) patients are alive. There was no disease- or procedure-related death. Conclusion: TEVAR in patients with connective tissue diseases is feasible but still questionable regarding their young age and the rates of endoleaks and reintervention due to disease progression. Close surveillance is mandatory. Low morbidity and mortality rates may justify TEVAR in emergencies as a "bridging" method
    Type of Publication: Journal article published
    PubMed ID: 18426270
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