500 likes | 745 Views
Endoleak After Aortic Stent Graft Repair: Diagnosis by Color Duplex Ultrasound vs. Computed Tomography Scan. Roger T. Gregory, MD, RVT Paul H.S. Bloch, MD Dean T. Sato, MD, RVT Charles D. Goff, MD, RVT F. Noel Parent III, MD, RVT
E N D
Endoleak After Aortic Stent Graft Repair: Diagnosis by Color Duplex Ultrasound vs. Computed Tomography Scan Roger T. Gregory, MD, RVT Paul H.S. Bloch, MD Dean T. Sato, MD, RVT Charles D. Goff, MD, RVT F. Noel Parent III, MD, RVT Robert G. Gayle, MD, RVT Richard J. DeMasi, MD, RVT George H. Meier, MD, RVT Jock R. Wheeler, MD Eastern Virginia Medical School Norfolk, Virginia
Endoleak After Aortic Stent Graft Repair: Diagnosis by Color Duplex Ultrasound vs. Computed Tomography Scan Paul H.S. Bloch, M.D. Roger T. Gregory, MD, RVT Dean T. Sato, MD, RVT Charles D. Goff, MD, RVT F. Noel Parent III, MD, RVT Robert G. Gayle, MD, RVT Richard J. DeMasi, MD, RVT George H. Meier, MD, RVT Jock R. Wheeler, MD Eastern Virginia Medical School Norfolk, Virginia
Introduction • Endovascular surgical treatment of abdominal aortic aneurysm (AAA) is here now. • Repair of AAA with stent graft techniques is both technically possible and safe • As technology improves, a greater proportion of patients will be candidates for endovascular repair. • Long term outcome = ???
Endovascular Technologies (EVT) Stent Graft for AAA Repair • Phase I results of the Tube Endograft (n=46)* • Initial success rate 39 (85%) • Hospital stay (mean) 3.8 days • Complications • Stent fracture 9 (23%) • Endoleak (CT) 17 (44%) • Spontaneous seal 9 (53%) *Moore WS, Rutherford RB, et al. JVS. 1996;23:543-53
Terminology • Endoleak • Endoleakage • Perigraft flow • Perigraft leak • Periprosthetic flow
Endoleak Sites for potential leak: • Attachment Site • Superior stent attachment • Inferior stent attachment • Branch vessel • Inferior mesenteric artery (IMA) • lumbar artery / arteries
AAA sac Superior stent Attachment Site Endoleak Branch Vessel Endoleak IMA Inferior stent Lumbar a.
stent stent graft markers endoleak stent angiocatheter
Significance of Endoleak Natural history:AAA size at 1 year* • No leak: Decreases • Leak that seals: Decreases • Leak that does not seal: Increases *Matsumura et al. JVS. 1997;25:113
Significance of Endoleak • Endoleak may negate the goal of the procedure • Case reports of AAA rupture following stent graft repair
Advantages “Gold Standard” Contrast outside the graft, inside the AAA sac Very reliable for superior and inferior stent attachment site leaks Disadvantages “Static”/”snapshot” examination Less reliable for branch leaks due to timing problems of contrast administration Diagnosis of EndoleakContrast Enhanced Computed Tomography Scan (CT)
Advantages Less expensive Dynamic / “movie” Avoids both contrast & radiation Available PRN May be more reliable in the diagnosis of branch vessel leak Disadvantages Technologist dependent Not always technically possible (e.g. gas) Diagnosis of EndoleakColor DuplexUltrasound (CDU)
Study Purpose 1. Can CDU identify endoleak? 2. Is CDU comparable to CT in accuracy in the diagnosis of endoleak? 3. Is there an optimal CDU protocol in the evaluation of endoleak?
Study Purpose 1. Can CDU identify endoleak? 2. Is CDU comparable to CT in accuracy in the diagnosis of endoleak? 3. Is there an optimal CDU protocol in the evaluation of endoleak?
Methods • EVT trial for stent graft repair of AAA • Reviewed 100 CDU studies • 23 different centers • Dec. 1995 to Jan. 1997 • 74 AAA pts. implanted with the EVT Stent Graft • 50 Tube grafts • 24 Bifurcated grafts
Methods Criteria for a technically complete study: • Satisfactory B-mode images • Satisfactory color Doppler images • Assessment of the entire AAA sac by color Doppler • Confirmation of endoleak with spectral Doppler
Methods Criteria for a technically complete study: • Satisfactory B-mode images • Satisfactory color Doppler images • Assessment of the entire AAA sac by color Doppler • Confirmation of endoleak with spectral Doppler
Results Total CDU studies reviewed: n=100 • Satisfactory B-mode image 93 • Poor B-mode images 7 • Intestinal gas 3 • Excessive patient movement 1 • Poor instrumentation (2 echo, 1 old) 3
Methods Criteria for a technically complete study: • Satisfactory B-mode images • Satisfactory color Doppler images • Assessment of the entire AAA sac by color Doppler • Confirmation of endoleak with spectral Doppler
Results Satisfactory B-mode images n=93 • Satisfactory color Doppler images 76 (82%) • Unsatisfactory color Doppler images 17 (18%) • Color overgain 6 • Color undergain 6 • Excessive gas, movement 5
AAA EVT Bifurcated Stent Graft B-Mode Color Overgain Color Undergain
Methods Criteria for a technically complete study: • Satisfactory B-mode images • Satisfactory color Doppler images • Assessment of the entire AAA sac by color Doppler • Confirmation of endoleak with spectral Doppler
Methods Criteria for a technically complete study: • Satisfactory B-mode images • Satisfactory color Doppler images • Assessment of the entire AAA sac by color Doppler • Confirmation of endoleak with spectral Doppler
Results Satisfactory B-mode and color images n=76 • Color Doppler assessment 55 (72%) of the entire AAA sac Satisfactory B-mode images n=93 • Spectral Doppler assessment 26 (28%) of AAA sac for leaks
Results - Technically Satisfactory Studies Total CDU Studies reviewed n=100 • Technically Satisfactory Studies • B-mode image 93 % • B-mode image plus • adequate color Doppler images • assessment of entire AAA 19 % sac by color and spectral Doppler
CDU Assessment of Endoleak Satisfactory B-mode image, incomplete leak assessment Unsatisfactory B-mode image n = 100 SatisfactoryB-mode image, complete leak assessment
Study Purpose 1. Can CDU identify endoleak? 2. Is CDU comparable to CT in the accuracy of the diagnosis of endoleak? 3. Is there an optimal CDU protocol in the evaluation of endoleak?
Study Purpose 1. Can CDU identify endoleak? 2. Is CDU comparable to CT in the accuracy of the diagnosis of endoleak? 3. Is there an optimal CDU protocol in the evaluation of endoleak?
Methods • Comparison of endoleak data from 117 concurrent CT and CDU studies • Diagnosis made by the EVT Core Laboratory • endoleak positive, negative or indeterminate
Results CDU Leaks CT Leaks
Results • Sensitivity 97 % • Specificity 74 % • Positive predictive value 66 % • Negative predictive value 98 % • Accuracy 82 % • Kappa statistic .64
Results CDU Leaks CT Leaks
Results • Indeterminate studies • CDU 14/117 (12%) • Due to incomplete study • CT 3/117 ( 3%) • Due to problems with contrast administration
Results CDU Leaks CT Leaks
Results Discrepant studies 18/100 (18%) re-reviewed • CDU - CT + 1 • CDU incomplete • CDU + CT - 17 • All CT studies were accurate • 8 CDU studies incomplete • 7 CDU studies complete • 2 CDU’s unavailable for review
Study Purpose 1. Can CDU identify endoleak? 2. Is CDU comparable to CT in the accuracy of the diagnosis of endoleak? 3. Is there an optimal CDU protocol in the evaluation for endoleak?
Study Purpose 1. Can CDU identify endoleak? - YES!! 2. Is CDU comparable to CT in accuracy in the diagnosis of endoleak? 3. Is there an optimalCDU protocol in the evaluation of endoleak?
Methods Criteria for a technically complete study: • Satisfactory B-mode images • Satisfactory color Doppler images • Assessment of the entire AAA sac by color Doppler • Confirmation of endoleak with spectral Doppler
CDU Protocol • High resolution scanner • Technologist cognizant of stent graft & possibility of endoleak
CDU Protocol B-mode Image • AAA sac • Endograft • Stent attachment sites
CDU Protocol • Optimize color settings
CDU Protocol • Interrogate the entire AAA sac by color Doppler ultrasound • Direct attention at potential leak sites • Stent attachment • IMA & lumbar arteries
Aorta Transverse View AAA sac Endoleak Graft
CDU Protocol • Confirm all suspected endoleaks with spectral Doppler • Determine the location & extent of AAA sac involvement
Conclusions • > 90% of CDU studies technically possible • The majority of the CDU studies reviewed were of suboptimal technical quality • In spite of the poor technical quality in the majority of CDU studies, CDU was able to accurately diagnose endoleak when compared with CT
Conclusions • A standardized CDU methodology will improve diagnostic accuracy • CDU may be equal or superior to CT in the diagnosis of endoleak, particularly in the identification of branch vessel leak