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Attia MF, Brummel BR, Lex TR, Van Horn BA, Whitehead DC, Alexis F. Recent Advances in Polyesters for Biomedical Imaging. Adv Healthc Mater 2018; 7:e1800798. [PMID: 30295005 DOI: 10.1002/adhm.201800798] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 09/03/2018] [Indexed: 12/11/2022]
Abstract
Several synthetic materials exhibiting contrast imaging properties have become vital to the field of biomedical imaging. Polymeric biomaterials and metals are commonly used imaging agents and can assist in the monitoring of therapy response, migration, degradation, changes in morphology, defects, and image-guided surgery. In comparison to metals, most bio and synthetic polymers lack inherent imaging properties. Polymeric biomaterials, specifically polyesters, have gained a considerable amount of attention due to their unique properties including biocompatibility, biodegradation, facile synthesis, and modification capability. Polyester implants and nanomaterials are available on the market or are in clinical trials for many applications including: dental implants, cranio-maxilofacial implants, soft tissue sutures and staples, abdominal wall repair, tendon and ligament reconstruction, fracture fixation devices, and coronary drug eluting stents. This review aims to provide a summary of the recent developments of polyesters with bioimaging contrast properties. The three main approaches to prepare bioimaging polyesters (coating, encapsulation, and functionalization) are discussed in depth. Furthermore, commonly used imaging modalities including X-ray computed tomography, magnetic resonance imaging, ultrasound, fluorescence, and radionucleotide polyester contrast agents are highlighted. In each section, examples of impactful bioimaging polyesters in the five major imaging modalities are evaluated.
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Affiliation(s)
- Mohamed F. Attia
- Department of Bioengineering; Clemson University; 301 Rhodes Research Center Clemson SC 29634 USA
| | - Beau R. Brummel
- Department of Chemistry; Clemson University; 467 Hunter Laboratories Clemson SC 29634 USA
| | - Timothy R. Lex
- Department of Chemistry; Clemson University; 467 Hunter Laboratories Clemson SC 29634 USA
| | - Brooke A. Van Horn
- Department of Chemistry and Biochemistry; College of Charleston; 66 George St. Charleston SC 29414 USA
| | - Daniel C. Whitehead
- Department of Chemistry; Clemson University; 467 Hunter Laboratories Clemson SC 29634 USA
| | - Frank Alexis
- Department of Bioengineering; Clemson University; 301 Rhodes Research Center Clemson SC 29634 USA
- School of Biological Sciences and Engineering; Yachay Tech; Hacienda San José s/n; San Miguel de Urcuquí 100119 Ecuador
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Wei L, Yang C, Chen R. RFID‐based stent‐graft dynamic assessment for health cares. IET NETWORKS 2017. [DOI: 10.1049/iet-net.2016.0005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Lifang Wei
- Institute of Smart Agriculture and Forestry and Big Data, College of Computer and Information SciencesFujian Agriculture and Forestry UniversityFuzhou350002People's Republic of China
| | - Changcai Yang
- Institute of Smart Agriculture and Forestry and Big Data, College of Computer and Information SciencesFujian Agriculture and Forestry UniversityFuzhou350002People's Republic of China
| | - Riqing Chen
- Institute of Smart Agriculture and Forestry and Big Data, College of Computer and Information SciencesFujian Agriculture and Forestry UniversityFuzhou350002People's Republic of China
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van Prehn J, Vincken KL, Muhs BE, Barwegen GKW, Bartels LW, Prokop M, Moll FL, Verhagen HJM. Toward Endografting of the Ascending Aorta: Insight into Dynamics Using Dynamic Cine-CTA. J Endovasc Ther 2016; 14:551-60. [PMID: 17696632 DOI: 10.1177/152660280701400418] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose: To evaluate pulsatility and movement along the ascending thoracic aorta using dynamic electrocardiographically-gated 64-slice cine computed tomographic angiography (CTA). Methods: Diameter and area change and center of mass (COM) movement of the ascending thoracic aorta was determined per cardiac cycle in 15 patients at surgically relevant anatomical levels: (A) 5 mm distal to the coronary arteries, (B) 5 mm proximal to the innominate artery, and (C) halfway up the ascending aorta. Additionally, COM movement was determined 1 cm (level P) and 2 cm (level Q) distal from the origins of the innominate, left carotid, and left subclavian arteries. Eight gated datasets covering the cardiac cycle were used to reconstruct images at each level perpendicular to the aortic lumen. The distance between important anatomical landmarks was determined. Results: All levels showed significant cardiac cycle—induced diameter and area changes (p<0.001), with the largest pulsatility 5 mm distal to the coronary arteries. Mean maximum diameter changes were (A) 17.4%±4.8% (range 7.5%–27.5%), (B) 13.9%±3.5% (range 10.6%–25.0%), and (C) 12.9%±3.4% (8.3%–19.6%). Mean area changes were (A) 12.7%±5.5% (range 4.3%–21.8%), (B) 7.5%±2.0% (range 4.1%–11.0%), and (C) 5.6%±2.2% (range 1.9%–11.4%). Mean maximum COM movements were (A) 6.1±2.0 mm (range 2.7–9.0), (B) 2.3±1.1 mm (range 1.1–5.6), and (C) 3.6±1.5 mm (range 1.4–6.5). Mean COM movements of the innominate, left carotid, and left subclavian arteries, respectively, were (P) 1.960.7 mm (range 0.9–3.7), 2.4±0.6 mm (range 1.4–3.3), and 1.9±0.6 mm (range 0.8–2.8), and (Q) 1.8±0.7 mm (range 0.8–3.5), 1.8±0.6 mm (range 0.8–2.7), 1.9±0.6 mm (range 1.1–3.4). Conclusion: The dynamics of the ascending thoracic aorta and the arch vessels are impressive, showing a wide range of 3-dimensional motions. Future ascending arch branched and fenestrated thoracic endograft designs must consider this active local environment, as it may have implications for durability, sealing, and ultimate clinical success.
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Affiliation(s)
- Joffrey van Prehn
- Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands
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Ueda T, Takaoka H, Petrovitch I, Rubin GD. Detection of Broken Sutures and Metal-Ring Fractures in AneuRx Stent-Grafts by Using Three-dimensional CT Angiography after Endovascular Abdominal Aortic Aneurysm Repair: Association with Late Endoleak Development and Device Migration. Radiology 2014; 272:275-83. [DOI: 10.1148/radiol.14130920] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey DE, Eagle KA, Hermann LK, Isselbacher EM, Kazerooni EA, Kouchoukos NT, Lytle BW, Milewicz DM, Reich DL, Sen S, Shinn JA, Svensson LG, Williams DM. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the diagnosis and management of patients with thoracic aortic disease. A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology,American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons,and Society for Vascular Medicine. J Am Coll Cardiol 2010; 55:e27-e129. [PMID: 20359588 DOI: 10.1016/j.jacc.2010.02.015] [Citation(s) in RCA: 1002] [Impact Index Per Article: 71.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Geisbüsch P, Kotelis D, Hyhlik-Dürr A, Hakimi M, Attigah N, Böckler D. Endografting in the aortic arch - does the proximal landing zone influence outcome? Eur J Vasc Endovasc Surg 2010; 39:693-9. [PMID: 20452789 DOI: 10.1016/j.ejvs.2010.03.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVES To analyse early and midterm results of thoracic aortic endografting (TEVAR) in the aortic arch. METHODS Between January 1997 and February 2009 178 patients received TEVAR in the aortic arch at our institution. This population was subdivided into four groups according to the proximal landing zone (LZ) classification in the aortic arch by Ishimaru et al. and a retrospective analysis regarding perioperative mortality, morbidity and endoleak formation was performed. RESULTS The overall 30-day mortality rate was 14% with no statistical significant difference between LZ's 0-3 (p=0.274). Renal insufficiency (hazard ratio (HR) 2.5; p=0.0119), age >75 years (HR 3.1; p=0.0019) and emergency procedures (HR 8.9; p < 0.0001) were independent predictors of death. There was no significant difference regarding type I (p=0.07) or type III (p=0.49) endoleaks between the proximal LZs, but a significant difference regarding the development of type II endoleaks (p=0.01). CONCLUSIONS The present study showed no influence of the proximal LZ on perioperative mortality and morbidity rate. Furthermore it did not influence relevant (type I/III) endoleak formation.
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Affiliation(s)
- P Geisbüsch
- Department of Vascular and Endovascular Surgery, Ruprecht - Karls University Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany.
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Hiratzka LF, Bakris GL, Beckman JA, Bersin RM, Carr VF, Casey DE, Eagle KA, Hermann LK, Isselbacher EM, Kazerooni EA, Kouchoukos NT, Lytle BW, Milewicz DM, Reich DL, Sen S, Shinn JA, Svensson LG, Williams DM. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation 2010; 121:e266-369. [PMID: 20233780 DOI: 10.1161/cir.0b013e3181d4739e] [Citation(s) in RCA: 1179] [Impact Index Per Article: 84.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zarins CK, Taylor CA. Endovascular device design in the future: transformation from trial and error to computational design. J Endovasc Ther 2009; 16 Suppl 1:I12-21. [PMID: 19317584 DOI: 10.1583/08-2640.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Endovascular devices have been designed by trial and error, with bench and animal testing followed by human clinical trials to determine whether the devices are safe and effective. Despite remarkable advances over the past 15 years, there are persistent concerns regarding the long-term durability of endovascular devices. This may be due to deficiencies in device design, which has lagged behind other industries in adopting computational methods that are now routinely used to design, develop, and test new aircraft and automobiles. Similar computational design and failure mode simulations that evaluate performance under stress conditions have not been widely applied in the development of endovascular devices. Advances in medical imaging and computational modeling now allow simulation of physiological conditions in patient-specific 3-dimensional vascular models, which can provide a framework to design and test the next generation of endovascular devices. This modeling will allow the prospective design of devices that can withstand the force variations in the cardiovascular system that occur during bending, coughing, and varying degrees of exercise, as well as the extremes encountered during sudden impact in contact sports. Utilization of computational design methodology that takes into consideration the physiology of the cardiovascular system will improve future endovascular devices so that they are safer and more effective and durable.
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Affiliation(s)
- Christopher K Zarins
- Stanford University School of Medicine and School of Engineering, Stanford, California, USA.
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Koning OHJ, Kaptein BL, van der Vijver R, Dias NV, Malina M, Schalij MJ, Valstar ER, van Bockel JH. Fluoroscopic Roentgen stereophotogrammetric analysis (FRSA) to study three-dimensional stent graft dynamics. J Vasc Surg 2009; 50:407-12. [PMID: 19631876 DOI: 10.1016/j.jvs.2009.03.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 03/02/2009] [Accepted: 03/14/2009] [Indexed: 10/20/2022]
Abstract
We report the clinical feasibility of fluoroscopic Roentgen stereophotogrammetric analysis (FRSA), a validated method to quantify real time three-dimensional (3D) dynamic motion of stent grafts and the first clinical results after abdominal and thoracic endovascular repair (EVAR). Stent graft motion was measured at 30 (stereo) frames per second, during the cardiac cycle and in the patient after abdominal EVAR, due to respiratory action. Translational motions of the center of mass, diameter change, and rotational and axial motion could be measured. Quantification of 3D motion was not available until now. FRSA can provide crucial information on the forces exerted on stent grafts and will, therefore, provide essential information for improvements in stent graft design.
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Affiliation(s)
- Olivier H J Koning
- Department of Surgery, Division of Vascular Surgery, Leiden University Medical Center, Leiden, The Netherlands.
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McDonnell CO, Haider SN, Colgan MP, Shanik GD, Moore DJ, Madhavan P. Endovascular management of thoracic aortic pathology. Surgeon 2009; 7:24-30. [PMID: 19241982 DOI: 10.1016/s1479-666x(09)80063-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Endovascular technology has revolutionised the management of abdominal aortic aneurysmal disease but the less frequent occurrence of pathology in the thoracic aorta has meant that evidence demonstrating the primacy of endovascular treatment strategies in this portion of the vessel is less convincing. Herein we summarise the best available evidence to date. METHODS A comprehensive search of the surgical and radiological literature using the search term 'endovascular thoracic aorta' was conducted. FINDINGS AND CONCLUSIONS The vast majority of patients treated by thoracic aortic stent grafting have had their treatment outside the context of a randomised trial. While it would seem that endovascular repair is the treatment of choice for the thoracic aorta, the present evidence is based on single centre case series and is anecdotal at best.
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Affiliation(s)
- C O McDonnell
- Department ofVascular Surgery, Mater Misericordiae University Hospital, Dublin, Ireland.
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Methods for Quantifying Three-Dimensional Deformation of Arteries due to Pulsatile and Nonpulsatile Forces: Implications for the Design of Stents and Stent Grafts. Ann Biomed Eng 2008; 37:14-33. [DOI: 10.1007/s10439-008-9590-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022]
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Heartbeat-related displacement of the thoracic aorta in patients with chronic aortic dissection type B: quantification by dynamic CTA. Eur J Radiol 2008; 72:483-8. [PMID: 18805663 DOI: 10.1016/j.ejrad.2008.07.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 07/22/2008] [Accepted: 07/31/2008] [Indexed: 11/20/2022]
Abstract
PURPOSE The purpose of this study was to characterize the heartbeat-related displacement of the thoracic aorta in patients with chronic aortic dissection type B (CADB). MATERIALS AND METHODS Electrocardiogram-gated computed tomography angiography was performed during inspiratory breath-hold in 11 patients with CADB: Collimation 16 mm x 1 mm, pitch 0.2, slice thickness 1mm, reconstruction increment 0.8 mm. Multiplanar reformations were taken for 20 equidistant time instances through both ascending (AAo) and descending aorta (true lumen, DAoT; false lumen, DAoF) and the vertex of the aortic arch (VA). In-plane vessel displacement was determined by region of interest analysis. RESULTS Mean displacement was 5.2+/-1.7 mm (AAo), 1.6+/-1.0 mm (VA), 0.9+/-0.4 mm (DAoT), and 1.1+/-0.4mm (DAoF). This indicated a significant reduction of displacement from AAo to VA and DAoT (p<0.05). The direction of displacement was anterior for AAo and cranial for VA. CONCLUSION In CADB, the thoracic aorta undergoes a heartbeat-related displacement that exhibits an unbalanced distribution of magnitude and direction along the thoracic vessel course. Since consecutive traction forces on the aortic wall have to be assumed, these observations may have implications on pathogenesis of and treatment strategies for CADB.
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Koning OHJ, Kaptein BL, Garling EH, Hinnen JW, Hamming JF, Valstar ER, van Bockel JH. Assessment of three-dimensional stent-graft dynamics by using fluoroscopic roentgenographic stereophotogrammetric analysis. J Vasc Surg 2007; 46:773-9. [PMID: 17764877 DOI: 10.1016/j.jvs.2007.05.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 05/23/2007] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To validate the use of fluoroscopic roentgenographic stereophotogrammetric analysis (FRSA) for its feasibility and accuracy for measuring the three-dimensional dynamic motion of stent grafts. METHODS A digital biplane fluoroscopy setup was calibrated (Siemens Axiom Artis dBc). Stereo images were acquired of a static aortic model with a stent graft in different axial positions, imposed by a micromanipulator. The three-dimensional measurement error of FRSA was determined by comparing FRSA measurements with the micromanipulator. An aortic model with a stent graft was constructed and connected to an artificial circulation with a physiological flow and pressure profile. Markers were added to the spine (tantalum spherical markers; diameter 1 mm) and stent (welding tin; diameter 1 mm). The three-dimensional measurement precision was determined by measuring the position of a single (stable) spine marker during two pulsatile cycles. Finally, three-dimensional stent marker motion was analyzed with a frame rate of 30 images per second, including three-dimensional marker position (change), diameter change, and center of circle position change. RESULTS The mean error of FRSA measurement of displacement was 0.003 mm (SD, 0.019 mm; maximum error, 0.058 mm). A very high precision of position measurement was found (SD, 0.009-0.015 mm). During pulsatile motion, the position (changes) of the markers could be assessed in the x, y, and z directions, as well as the stent diameter change and center of circle position change. CONCLUSIONS FRSA has proven to be a method with very high accuracy and temporal resolution to measure three-dimensional stent-graft motion in a pulsatile environment. This technique has the potential to contribute significantly to the knowledge of stent-graft behavior after endovascular aneurysm repair and improvements in stent-graft design. The technique is ready for clinical testing.
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Affiliation(s)
- Olivier H J Koning
- Department of Surgery, Division of Vascular Surgery, Leiden University Medical Center, Leiden, The Netherlands.
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van Prehn J, Vincken KL, Muhs BE, Barwegen GKW, Bartels LW, Prokop M, Moll FL, Verhagen HJM. Toward Endografting of the Ascending Aorta:Insight into Dynamics Using Dynamic Cine-CTA. J Endovasc Ther 2007. [DOI: 10.1583/1545-1550(2007)14[551:teotaa]2.0.co;2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Zipfel B, Hammerschmidt R, Krabatsch T, Buz S, Weng Y, Hetzer R. Stent-grafting of the thoracic aorta by the cardiothoracic surgeon. Ann Thorac Surg 2007; 83:441-8; discussion 448-9. [PMID: 17257967 DOI: 10.1016/j.athoracsur.2006.09.036] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 09/05/2006] [Accepted: 09/07/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND We evaluated endovascular stent-grafting as a new technique in aortic surgery. METHODS One hundred ninety-six stent-grafts were implanted in the thoracic aorta in 172 patients. All procedures but one were performed in the operating room by a team of cardiothoracic surgeons; 112 operations (57%) were emergency procedures. Twenty-four procedures (12%) were reoperations for endoleaks. The left subclavian artery origin was covered in 46 cases and the left common carotid artery in 2 cases. Access was by femoral cut-down in 174 procedures, percutaneous femoral approach in 1, and by conduit to the iliac arteries or infrarenal aorta in 17. Surgical reconstruction of damaged access vessels became necessary in 10 cases. RESULTS Thirty-day mortality was 9.7% (19 patients). Paraplegia occurred in 1.0% (2 patients). Primary technical success was 85.2%, secondary 91.8%. Six conversions to open repair were necessary, 3 during the procedures and 3 secondarily before discharge. Actuarial survival was 79% at 1 year, 67% at 3 years, and 55% at 5 years. CONCLUSIONS The results are excellent, taking into account the high incidence of emergency procedures and that open surgery is not promising in many patients. The cardiothoracic surgeon can perform the procedure after adequate training in endovascular techniques. Surgical skills are mandatory because of the potential need for extended surgical approach to the access vessels or immediate conversion to open surgery. Therefore, the operating room is the preferred site for this procedure.
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Affiliation(s)
- Burkhart Zipfel
- Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Berlin, Germany.
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van Herwaarden JA, Bartels LW, Muhs BE, Vincken KL, Lindeboom MYA, Teutelink A, Moll FL, Verhagen HJM. Dynamic magnetic resonance angiography of the aneurysm neck: Conformational changes during the cardiac cycle with possible consequences for endograft sizing and future design. J Vasc Surg 2006; 44:22-8. [PMID: 16828422 DOI: 10.1016/j.jvs.2006.03.028] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Accepted: 03/03/2006] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Proper proximal fixation and stent-graft sealing within the aneurysm neck are critical for endovascular aneurysm repair (EVAR) durability. Computed tomography angiography (CTA) is the gold standard for preoperative sizing of endograft diameters, but the accuracy of these measurements is uncertain because they rely on static images of a dynamic process. The aortic configuration and diameter may change during the cardiac cycle. We studied these phenomena using dynamic electrocardiograph-triggered magnetic resonance angiography (MRA). METHODS Eleven consecutive EVAR patients were included. Dynamic MRA was used to perform preoperative and postoperative measurements. Changes were measured in transverse aortic sections 10 mm below the lowest renal artery (level A), at the level of the renal arteries (level B), and 3 cm above the lowest renal artery (level C). Data were analyzed using image segmentation software. Aortic area and diameter changes along 256 axes were determined. RESULTS Dynamic MRA demonstrated significant aortic area changes during the cardiac cycle before and after EVAR at all three measured levels. Pre-EVAR aortic area significantly increased per cardiac cycle: 8.4% at level A; 9.3% at level B; and 13.3% at level C (P < .001 for all levels). Post-EVAR aortic area increased 9.7% at level A, 9.6% at level B, and 15.8% at level C per cardiac cycle (P < .001 for all levels). Significant diameter changes during cardiac cycles were also observed at all three levels. Pre-EVAR mean diameter changed up to 8.9% (P < .001) compared with post-EVAR aortic changes of up to 11.5% (P < .001). EVAR had no effect on change in aortic area and diameter. Dynamic MRA also demonstrated that pulsatile aortic distension was not equal in all axes, but rather occurred as an asymmetrical expansion and contraction. CONCLUSION In patients with (atherosclerotic) aneurysm disease, the aortic dimensions at the level of and proximal to the aneurysm neck change during the cardiac cycle. This phenomenon is preserved after EVAR. Therefore, maximum diameter using dynamic MRA may not be similar to the maximum diameter with static CTA in all patients, and a standard regimen of 10% to 15% oversizing of an endograft based on static CTA images may be inadequate for some patients. Further studies using dynamic MRA to evaluate effects of different endografts are anticipated, with possible consequences for endograft designs.
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Affiliation(s)
- Joost A van Herwaarden
- Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
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