Doppler ultrasound role in the evolution and evaluation of the complications of vascular hemodyalisis access.

Transcription

1 Doppler ultrasound role in the evolution and evaluation of the complications of vascular hemodyalisis access. Poster No.: C-1675 Congress: ECR 2015 Type: Educational Exhibit Authors: M. E. Banegas Illescas, A. Pinar Ruiz, M. L. Rozas Rodríguez, L. Caminero Pardo, M. T. Gomez San Roman ; Ciudad Real/ES, 2 PUERTOLLANO/ES Keywords: Vascular, Extremities, Management, Ultrasound-Colour Doppler, Ultrasound-Spectral Doppler, Ultrasound-Power Doppler, Venous access, Shunts, Diagnostic procedure, Hemodynamics / Flow dynamics DOI: /ecr2015/C-1675 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 23

2 Learning objectives - To highlight the importance of colour doppler ultrasound (CD-US) in the management of vascular access (VA) for hemodialysis (native fistula and arteriovenous graft). - To review and describe the doppler ultrasound findings of dysfunction and complications of the arteriovenous fistulas. Background The incidence and prevalence of the chronic renal disease that needs treatment have increased more than a 100% in the last 15 years. The age group that has had a greatest percentage increase is in patients in patients more than 75 years old (from 8'5% of patients in 1992 to 40% currently), In this group, most of them are treated with hemodialysis and fewer change the technique. The two more used types of vascular access for hemodialysis currently are central venous catheter and arteriovenous fistulas. These can be autologous or graft Fig. 1 on page 3. The ideal vascular access for hemodialysis (HD) must fulfill at least three requisites: to allow a safe and repeated access, to give sufficient flow to administer the HD dose, and have fewer complications. That is why, to achieve an optimum hemodialysis it is fundamental to count with an efficient vascular access. The native AV fistula (AVF) has demonstrated that it reduces mortality and morbidity (complications are 10 times more frequent with arteriovenous grafts (AVG)). Though AVF is the first election vascular access Fig. 2 on page 3 y Fig. 3 on page 4, it is not always possible to perform it and we need to use AVG Fig. 4 on page 5. Page 2 of 23

3 Images for this section: Fig. 1: Operating mechanisms of the native arteriovenous fistulas (A) and grafts (B). Page 3 of 23

4 Fig. 2: Diagram that shows the different types of arteriovenous anastomosis with radial artery and cephalic vein. A) Latero-lateral (the most frequent), B) Termino-lateral (with the end of the artery in the venous side)), C) Termino-lateral (with the end of the vein in the arterial side) and D) Termino-terminal. Page 4 of 23

5 Fig. 3: Schematic diagram that shows the different types of upper limb arteriovenous fistulas. Page 5 of 23

6 Fig. 4: Schematic diagram that shows the different types of upper limb arteriovenous grafts. Page 6 of 23

7 Findings and procedure details Artrography is the gold standard technique in the evaluation of non functional vascular access, however CD-US is very useful and first line tool to evaluate the status of the vascular access, identifying the presence of complications and their location, and to obtain hemodynamic data as well as to plan the intravascular procedure Fig. 5 on page 9, Fig. 6 on page 10 y Fig. 7 on page years ago, Tordoir et al proposed doppler ultrasound for the follow up and evaluation of arteriovenous fistulas, and currently this technique is of great value in expert hands because it is a fast, accessible, cheap and non invasive technique that allow us to perform a morphological evaluation and to obtain dynamic flow data Fig. 8 on page 13. Doppler ultrasound has three applications in the management of hemodialysis vascular access: 1) Mapping and planning of the AV construction for the venous and arterial evaluation of the upper limb; 2) in the period of maturity and 3) in the detection and characterization of complications (stenosis, thrombosis, infection, steal syndrome, aneurysms and pseudoaneurysms). Mapping and planning. Derivation surgery is recommended to patients in a 4-5 stage of chronic renal disease (stage 4: glomerular filtration of 15.29ml/min 1'73 m2; stage 5: glomerular filtration < 15 ml/min 1'73m2). In the common practice, the vascular appropriateness for the placement of an AVF is determined by a clinical specific examination. However, currently the international guides (National Kidney Foundation-Diálisis Outcomes Quality Initiative (NKF-DOQI) sustain the routine use of doppler ultrasound for the presurgical vascular mapping that is indicated in patients with DM, obese, elderly, and patients with peripheral vascular compromise. There must be an evaluation of several parameters: resistivity index, arterial diameter, arterial flow previously and after proximal venous compression. Maturity period. Maturity of the vascular access is a dynamic process that is characterized by the sudden decrease of the resistivity and a secondary increase of the flow velocity. This two Page 7 of 23

8 conditions modify the hemodynamic pressure of the the wall that causes remodeling and dilatation of the vessel. The AVF needs more time to develop (usually 2-3 months and 4 weeks as the minimal time) than AVG (two weeks). CD-US is a very important tool for the evaluation of the AVF in the maturity period with the evaluation of different parameters Table 1 on page 13. To remember the normal features of maturity of the AVF we have the rule of Sixties characteristicss: a flow greater than 600 ml/min, arterial diameter greater than 0'6 cm and a depth of approximately 0'6 cm Fig. 9 on page 14. Monitoring of the fistula and detection of complications. The early detection of an AVF dysfunction and correction before a thrombus develops, prolongs the survival of the fistulas, decreases the number of hospital admissions related and improves the appropriate functionality of the fistula. With doppler ultrasound the normal functioning AVF and AVG have a monophasic flow pattern of the artery and the graft, with a peak systolic velocity (PSV) of cm/s and telediastolic velocity (TDV) of cm/s. The efferent veins have arterial pulsation with a PSV of cm/s. 1. Thrombosis. Though less than the grafts (AVG), AVF can suffer complications, the most frequent is a thrombotic occlusion. Thrombosis is usually located in the arteriovenous anastomosis of the AVF and/or next to the venous anastomosis in AVG. Depending on the causes, thrombosis can be early (in the first three months) or late (more than three months) associated with stenosis. In ultrasound we see an absence of flow using color or pulsed doppler secondarily to an anechogenic or hypoechogenic vascular occupation Fig. 10 on page 15 y Fig. 11 on page Stenosis. Stenosis is defined as a decrease of the vascular diameter of more than 50%, associated to functional and hemodynamic changes that determine the flow reduction. Stenosis in AVF develops more frequently in the entry zone of the fistula, next to the arterial anastomosis, while in grafts they develop in the outflow tract of the anastomosis between the vein and the graft. In Brescia-Cimino fistulas, the more frequent location is the proximal venous margin several cm away of the anastomosis and they are secondary to the trauma caused by the repeated punctures. Page 8 of 23

9 In AVF, stenosis is caused by the intimal or fibromuscular hyperplasia secondary to endothelial damage because of the pressure increase in the venous system. In grafts, they can be caused by the chronic deposition of fibrin and cells. By using US or color doppler (CD-US), we can see a decrease of the vascular lumen that can associate perivascular artifact, and an increase of the flow velocity and aliasing Fig. 12 on page 17 y Fig. 13 on page 18. The diagnosis of venous stenosis are more complicated than the arterial because of they need a combination of morphological and functional criteria Table 2 on page Infection. Infection is more frequent in AVG than in AVF. being the second more frequent complication after thrombosis, specially in synthetic grafts and in lower limbs. Infections can be local or involve all the graft. In US we can identify fluid surrounding the graft more evident at the anastomosis level, that can be differentiated from serous fluid collections that can be seen because of the serous filtration through the graft. 4. Aneurysms and pseudoaneurysms. Aneurysms and pseudoaneurysms are usually developed by vascular destruction after repeated punctures. Spectral doppler ultrasound can differentiate pseudoaneurysm from hematomas because they have a typical "to-and-fro" pattern Fig. 14 on page 20. Venous aneurysms are usually identified in Brescia-Cimino fistulas; the CD-US is very useful to determine the aneurysm extent (depending on if they are greater or smaller than 5 mm they are classified as micro or macro-aneurysms), and to evaluate the presence of thrombotic material inside, criteria that determine if the surgical correction is required. 5. Steal syndrome. Arterial steal syndrome is defined as retrograde flow in the native artery, distal to the anastomosis Fig. 15 on page 21. The steal phenomenon is frequent and happens approximately about 2/3 of the fistulas, being usually asymptomatic because of the development of collateral flow, and only 2-6% have ischemic symptoms. Images for this section: Page 9 of 23

10 Fig. 5: Protocol of our institution for the evaluation of patients with vascular access. Page 10 of 23

11 Fig. 6: CD-US examination to evaluate the existence of pseudoaneurysms A) previous to percutaneous treatment, (B, C and D), that allow us to plan the most appropriate approach point. Page 11 of 23

12 Page 12 of 23

13 Fig. 7: Ultrasound guided PTA in an iodinated contrast material allergic patient. Balloon catheter centered in the stenotic area (A) and later inflated (B). Fig. 8: Examples of both normal AVF and AVG. A) Radio-cephalic arteriovenous fistula. B) Brachio-cephalic arteriovenous fistula. C) Arteriovenous graft. Page 13 of 23

14 Table 1: CD-US parameters in evaluating AVF maduration Page 14 of 23

15 Fig. 9: Evaluation of madurity parameters: diameter (figure A), depth from the skin (B), and flow volume (C and D). Page 15 of 23

16 Fig. 10: Partial thrombosis in different native arteriovenous fistulas. Page 16 of 23

17 Fig. 11: Complete thrombosis in different graft arteriovenous fistulas. Page 17 of 23

18 Fig. 12: Stenosis of the juxta-anastomotic venous margin of an AVF (A and B). We can see a decrease of the diameter with perivascular artifact and aliasing (arrowhead in A) and an increase of flow velocity (B). AVG stenosis (C and D) with the same features. Page 18 of 23

19 Fig. 13: Juxta-anastomotic stenosis in an radio-cephalic AVF (A). Correlation of the ultrasound with the angiographic image (B). Percutaneous treatment with angioplasty (PTA) (C and D) and final result (E). Page 19 of 23

20 Table 2: Table 2 Page 20 of 23

21 Fig. 14: Hypoechogenic collection (A) with flow replenishing with color dopper ultrasound (B) compatible with pseudoaneurysm (partially thrombosed) in a native arteriovenous fistula. Pseudoaneurysms in graft arteriovenous fistulas (C and D). Page 21 of 23

22 Fig. 15: Schematic diagram that shows the arterial steal syndrome mechanism with inversion of the flow direction (gree arrow) in the distal native artery to the anastomosis. Page 22 of 23

23 Conclusion Though artrography is the gold standard technique in the evaluation of AV, color doppler ultrasound can be superior in some aspects because it give us vascular morphological and functional data, and above all, because of its availability and low cost, it is useful for the fast and first line evaluation of non functional fistulas and grafts. Personal information References - Ultrasound as a Tool for Preoperative Planning, Monitoring, and Interventions in DialysisArteriovenous Access.SurendraShenoy, MichaelDarc AJR:201, October2013.The key role of color doppler ultrasound in the work-up ofhemodialysis vascular access. Lomonte C,Meola M,Petrucci I,Casucci F,BasileC.Semin Dial Upper Extremity Venous DopplerUltrasoundTherese M.Weber,Mark E. Lockhart, MD, MPH,Michelle L.Robbin, MDRadiol.Clin N Am 45 : , Exploración vascular no invasiva del antebrazo mediante ecografía Doppler color (EDC) antes y después de la construcción de la fístula radiocefálica (FRC). R. RocaTey, A. et al. Nefrología vol 27, Preoperative Sonographic Radial Artery Evaluation and Correlation With SubsequentRadiocephalic Fistula Outcome. Mark E. Lockhart, MD et al. J Ultrasound Med 23: , Sonographic Evaluation of Upper Extremity Deep Venous Thrombosis. Eva E. Chin, MD, Peter T. Zimmerman, MD, Edward G. Grant, MD. J Ultrasound Med ; 24: , US Vascular Mapping before Hemodialysis Access Placement. Michelle L. Robbin, MD et al. Radiology 217:83-88, CephalicVein andhemodialysis FistulaSurgeon'sObservation Versus ColorDopplerUltrasonographicFindings IsmailMihmanli, MD et al.jultrasoundmed 20: , HemodialysisArteriovenous Fistula Maturity: US Evaluation.Michelle L.Robbin, MDet al. Radiology 225:59-64, The clinical utility of vascular mapping with Doppler ultrasound prior to arteriovenous fistula construction forhemodialysis access. Ilhan G, Esi E, Bozok S, Yürekli I, Ózpak B, Ózalci A, Destan B et al. J Vasc Access 2013; 14(1):83-8 Page 23 of 23