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  • 1
    Keywords: AGE, aneurysm, ANEURYSMS, Aorta, ARCH, ARTERY, COMPLEX, COMPLICATIONS, DESCENDING THORACIC AORTA, DI
    Abstract: Objective: We report our 6-year experience with the visceral hybrid procedure for high-risk patients with thoracoabdominal aortic aneurysms (TAAA) and chronic expanding aortic dissections (CEAD). Methods. Hybrid procedure includes debranching of the visceral and renal arteries followed by endovascular exclusion of the aneurysm. A series of 28 patients (20 male, mean age 66 years) were treated between January 2001 and July 2007. Sixteen patients had TAAAs type I-III, one type IV, four thoracoabdominal placque ruptures, and seven patients CEAD. Patients were treated for asymptomatic, symptomatic, and ruptured aortic pathologies in 20, and 4 patients, respectively. Two patients had Marfan's syndrome; 61% had previous infrarenal aortic surgery. The infrarenal aorta was the distal landing zone in 70%. In elective cases, simultaneous approach (n = 9, group I) and staged approach (n = 11, group 11) were performed. Mean follow-up is 22 months (range 0.1-78). Results: Primary technical success was achieved in 89%. All stent grafts were implanted in the entire thoracoabdominal aorta. Additionally, three patients had previous complete arch vessel revascularization. Left subclavian artery was intentionally covered in three patients (11%). Thirty-day mortality rate was 14.3% (4/28). One patient had a rupture before the staged endovascular procedure and died. Overall survival rate at 3 years was 70%, in group 180%, and in group II 60% (P =.234). Type I endoleak rate was 8%. Permanent paraplegia rate was 11%. Three patients required long-term dialysis (11%). Peripheral graft occlusion rate was 11% at 30 days. Gut infarction with consecutive bowel resection occurred in two patients. There was no significant difference between group I and II regarding paraplegia and complications. Conclusions. Early results of visceral hybrid repair for high-risk patients with complex and extended TAAAs and CEADs are encouraging in a selected group of high risk patients in whom open repair is hazardous and branched endografts are not yet optional
    Type of Publication: Journal article published
    PubMed ID: 18381133
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  • 2
    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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  • 3
    Abstract: The endovascular era began about 20 years ago and subsequently revolutionized vascular surgery as a less invasive treatment option, especially for high risk patients. In the late 1990s, a new hybrid approach for arch and thoracoabdominal pathologies was developed. Debranching and rerouting supra-aortic and visceral aortic branches with extra-anatomic bypass grafting was performed in order to achieve sufficient landing zones demanding for subsequent stent grafting. The initial single-center results of small series up to 20 patients were encouraging with acceptable complication rates. Hybrid arch procedures are feasible but seem to carry risks. However, the latest reports for thoracoabdominal hybrid procedures demand a word of caution due to high morbidity rates. The hybrid approach may be reserved for a selected comorbid patient cohort, which is regarded unfit for open reconstruction
    Type of Publication: Journal article published
    PubMed ID: 19734831
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  • 4
    Keywords: ACCURACY ; BLOOD-FLOW ; PATTERNS ; HEALTHY-VOLUNTEERS ; phase-contrast MRI ; CARDIOVASCULAR MAGNETIC-RESONANCE ; TO-NOISE RATIOS ; WHOLE HEART ; 4D FLOW ; COARCTATION
    Abstract: Three-dimensional velocity-encoded cine magnetic resonance imaging (3D VEC MRI) allows for calculation of secondary flow parameters that may be used to estimate prognosis of individual cardiovascular diseases. However, its accuracy has not been fully investigated yet. The purpose of this study was to validate aortic flow quantification by 3D VEC MRI in vitro and in vivo using stacked two-dimensional acquisitions. Time-resolved stacks of two-dimensional planes with three-directional velocity-encoding (stacked-2D-3dir-MRI) were acquired in an elastic tube phantom with pulsatile flow simulating aortic flow as well as in 11 healthy volunteers (23 +/- 2 years). Previously validated two-dimensional through-plane VEC MRI at six equidistant levels in vitro and three locations in vivo (ascending aorta/aortic arch/descending aorta) was used as reference standard. The percentage difference of the stacked-2D-3dir-MRI measurement to the reference standard was defined as the parameter for accuracy. For in vitro aortic flow, stacked-2D-3dir-MRI underestimated average velocity by -6.8% (p 〈 0.001), overestimated average area by 13.6% (p 〈 0.001), and underestimated average flow by -7.4% (p 〈 0.001). Accuracy was significantly higher in the field of view centre compared to off-centre (p = 0.001). In vivo, stacked-2D-3dir-MRI underestimated average velocity (all three locations p 〈 0.001) and overestimated average area at all three locations (p = n.s./〈0.001/〈0.001). Average flow was significantly underestimated in the ascending aorta (p = 0.035), but tended to be overestimated in the aortic arch and descending aorta. In conclusion, stacked-2D-3dir-MRI tends to overestimate average aortic area and to underestimate average aortic velocity, resulting in significant underestimation of average flow in the ascending aorta.
    Type of Publication: Journal article published
    PubMed ID: 22362096
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  • 5
    Keywords: GROWTH ; PATIENT ; RESPONSES ; SIMULATION ; FLOW ; VELOCITY ; thrombus ; RUPTURE ; WALL SHEAR-STRESS
    Abstract: Objectives: To evaluate hemodynamic changes during aneurysmal dilatation in chronic type B aortic dissections compared to hemodynamic parameters in the healthy aorta with the use of computational fluid dynamics (CFD). Methods: True lumen (TL)/false lumen (FL) dimensional changes, changes in total pressure (TP), and wall shear stress (WSS) were evaluated at follow-up (FU) compared to initial examination (IE) with transient CFD simulation with geometries derived from clinical image data and inflow boundary conditions from magnetic resonance images. The TL/FL pressure gradient between ascending and descending aorta (DAo) and maximum WSS at the site of largest dilatation was compared to values for the healthy aorta. Results: Hemodynamic changes at site of largest FL dilatation included 77% WSS reduction and 69% TP reduction. Compared to the healthy aorta, pressure gradient between ascending and DAo was a factor of 1.4 higher in the TL and a factor of 1.5 in the FL and increased at FU (1.6 and 1.7, respectively). Maximum WSS at the site of largest dilatation was a factor of 3 lower than that for the healthy aorta at IE and decreased by more than a factor of 2 at FU. Conclusions: The FL dilatation at FU favorably reduced TP. In contrast, unfavorable increase in pressure gradient between ascending and DAo was observed with higher values than in the healthy aorta. Maximum WSS was reduced at the site of largest dilation compared to healthy aorta.
    Type of Publication: Journal article published
    PubMed ID: 24048257
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  • 6
    Abstract: PURPOSE: To evaluate different centerline analysis applications using objective ground truth from realistic aortic aneurysm phantoms with precisely defined geometry and centerlines to overcome the lack of unknown true dimensions in previously published in vivo validation studies. METHODS: Three aortic phantoms were created using computer-aided design (CAD) software and a 3-dimensional (3D) printer. Computed tomography angiograms (CTAs) of phantoms and 3 patients were analyzed with 3 clinically approved and 1 research software application. The 3D centerline coordinates, intraluminal diameters, and lengths were validated against CAD ground truth using a dedicated evaluation software platform. RESULTS: The 3D centerline position mean error ranged from 0.7+/-0.8 to 2.9+/-2.5 mm between tested applications. All applications calculated centerlines significantly different from ground truth. Diameter mean errors varied from 0.5+/-1.2 to 1.1+/-1.0 mm among 3 applications, but exceeded 8.0+/-11.0 mm with one application due to an unsteady distortion of luminal dimensions along the centerline. All tested commercially available software tools systematically underestimated centerline total lengths by -4.6+/-0.9 mm to -10.4+/-4.3 mm (maximum error -14.6 mm). Applications with the highest 3D centerline accuracy yielded the most precise diameter and length measurements. CONCLUSION: One clinically approved application did not provide reproducible centerline-based analysis results, while another approved application showed length errors that might influence stent-graft choice and procedure success. The variety and specific characteristics of endovascular aneurysm repair planning software tools require scientific evaluation and user awareness.
    Type of Publication: Journal article published
    PubMed ID: 28587563
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  • 7
    Keywords: ACQUISITION, ADAMKIEWICZ ARTERY, ANGIOGRAPHY, Aorta, aorta,thoracic, cardiovascular, CARE, chest, CH
    Abstract: Almost 50 years after its introduction intra-arterial digital subtraction angiography (DSA) has been passed as the gold standard for diagnostic imaging of the aorta. Today's performance of multi-detector-row computed tomography angiography (CTA) as well as magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) offer remarkable improvements in the field of diagnostic cardiovascular imaging. The racy developments not only concerning image acquisition but also image postprocessing offer a multidimensional approach to assess anatomy and pathology of individual patients in a few minutes. Four-dimensional visualization assists us to select the "adequate" patient, quantify vascular and adjacent geometries, and select the appropriate device to realize even complex thoracic endovascular aortic reconstructions (TEVAR). There is still a discrepancy between perioperative and intraoperative imaging -but new technologies made also some progress in this field. Lifelong imaging surveillance of TEVAR and bypasses is still a critical component of patient care and requires comparable imaging and postprocessing capabilities as for the preoperative setting. Although is the most commonly used examination for imaging surveillance, MRA, chest x-ray and DSA all have their role in determining complications and their management
    Type of Publication: Journal article published
    PubMed ID: 18665106
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  • 8
    Abstract: BACKGROUND: To analyze the sequelae of the intentional left subclavian artery (LSA) coverage during thoracic endovascular aortic repair (TEVAR). METHODS: Retrospective analysis of prospectively collected data in a single center. Between March 1997 and October 2008, 88 of 220 patients (40%) had thoracic aortic lesions that required LSA coverage during TEVAR. Thirty-four of our patients (39%) were treated under urgent or emergent conditions for acute pathologies. The proximal landing zone was zone 0 in 10 patients (11%), zone 1 in 24 patients (27%), and zone 2 in 54 patients (61%). Debranching procedures of the supra-aortic vessels were performed in patients who were to undergo zone 0 or zone 1 deployment. Primary LSA revascularization was performed in 22 of the 88 patients (25%) at a median of 6 days before TEVAR. Median follow-up was 26.4 months (1-98 months). RESULTS: Technical success was achieved in 97%. Five primary (9%) and two secondary (4%) type Ia endoleaks in patients who underwent zone 2 deployment were observed and required further interventions. Fourteen (16%) primary type II endoleaks were observed; 10 of them fed by the LSA. Paraplegia rate was lower in patients with LSA coverage without revascularization than in other patients (1.5% vs 1.9%; odds ratio [OR], 0.774; 95% confidence interval [CI], 0.038-6.173; P = 1.000). Prior or concomitant infrarenal aortic replacement (P = .0019), renal insufficiency (glomerular filtration rate 〈 90 mL/min/1.73 m(2)) (P = .0024) and long segment aortic coverage (〉200 mm) (P = .0157) were associated with significant higher risk of postoperative paraplegia. Stroke rate was lower in patients with LSA coverage without revascularization than in other patients (3% vs 3.9%; OR, 0.570; 95% CI, 0.118-2.761; P = .7269). Two patients (3%) developed left upper extremity symptoms and another two patients (3%) subclavian steal syndrome and required secondary LSA revascularization. The technical success rate for LSA revascularization was 94%. CONCLUSION: By using a selective approach to the LSA revascularization, coverage of the LSA can be used to extend the proximal seal zone for TEVAR without increasing the risk of spinal cord ischemia or stroke. Indications for revascularization include long segment aortic coverage, prior or concomitant infrarenal aortic replacement, and renal insufficiency. In addition, a hypoplastic right vertebral artery, a patent left internal mammary artery graft, and a functioning dialysis fistula in the left arm would also be indications to perform revascularization
    Type of Publication: Journal article published
    PubMed ID: 19837529
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  • 9
    Keywords: MAGNETIC-RESONANCE ANGIOGRAPHY ; MULTISLICE COMPUTED-TOMOGRAPHY ; LOW TUBE VOLTAGE ; COMPUTATIONAL FLUID-DYNAMICS ; SEMIAUTOMATIC CENTERLINE ANALYSIS ; CARDIOVASCULAR-INTERVENTIONS EAPCI ; EXPANDING COREVALVE PROSTHESIS ; CARDIOTHORACIC-SURGERY EACTS ; EXPERT CONSENSUS DOCUMENT ; RADIATION-DOSE REDUCTION
    Abstract: Transcatheter aortic valve replacement (TAVR) as well as thoracic and abdominal endovascular aortic repair (TEVAR and EVAR) rely on accurate pre- and postprocedural imaging. This review article discusses the application of imaging, including preprocedural assessment and measurements as well as postprocedural imaging of complications. Furthermore, the exciting perspective of computational fluid dynamics (CFD) based on cross-sectional imaging is presented. TAVR is a minimally invasive alternative for treatment of aortic valve stenosis in patients with high age and multiple comorbidities who cannot undergo traditional open surgical repair. Given the lack of direct visualization during the procedure, pre- and peri-procedural imaging forms an essential part of the intervention. Computed tomography angiography (CTA) is the imaging modality of choice for preprocedural planning. Routine postprocedural follow-up is performed by echocardiography to confirm treatment success and detect complications. EVAR and TEVAR are minimally invasive alternatives to open surgical repair of aortic pathologies. CTA constitutes the preferred imaging modality for both preoperative planning and postoperative follow-up including detection of endoleaks. Magnetic resonance imaging is an excellent alternative to CT for postoperative follow-up, and is especially beneficial for younger patients given the lack of radiation. Ultrasound is applied in screening and postoperative follow-up of abdominal aortic aneurysms, but cross-sectional imaging is required once abnormalities are detected. Contrast-enhanced ultrasound may be as sensitive as CTA in detecting endoleaks.
    Type of Publication: Journal article published
    PubMed ID: 24429327
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