The Role of IntraHoperative Duplex Imaging in Arterial Reconstructions

Allen Yu, MD, FACS, Donna Gregory, RVT, Leslie Morrison, RVT, Sara Morgan, RVT, Tacoma, Washington

BACKGROUND: This study is a cost-benefit analy- sis of a less invasive method of intra-operative duplex imaging compared with the use of intra- operative angiogram (including C-arm fluoros- copy) in arterial reconstruction.

METHODS: From September 1994 to May 1995,93 intra-operative duplex imaging studies were per- formed. Duplex scanning results were recorded for carotid endarterectomy (35), iliac balloon an- gioplasty and stent placement(l2), and infra-in- guinal bypass (46). Average cost and time were calculated for each type of study.

RESULTS: Thirty-four carotid endarterectomy pa- tients (97%) had normal duplex findings. Three (9%) underwent intra-operative angiogram due to abnormal duplex findings and post-operative neurological deficit. In iliac balloon angioplasty and stent placement cases (12), both intra-opera- tive duplex and C-arm post-stent angiography yielded comparable results in both normal (11) and abnormal (1) studies. In infra-inguinal bypass cases (46), 2 had abnormal duplex findings of the native vessels. Average time and cost required to perform intra-operative duplex studies is signifi- cantly less than that required for intra-operative angiogram or C-arm studies.

CONCLUSION: Compared with traditional intra- operative angiography, the use of intra-operative duplex imaging is less expensive, less invasive, quicker, and equally accurate when used as an adjunct to access surgical results of arterial re- constructions. Am J Surg. 1996;171:500-501

PATIENTS AND METHODS

F rom September 1994 through May 1995, 93 intra-op- erative duplex imaging studies were performed. There were three categories of surgical procedures involved

in the study: carotid endarterectomy (35) ; iliac artery bal- loon angioplasty with stent placement (12); and infi-a-in- guinal bypass (46). All arterial reconstructive procedures were evaluated by means of color flow duplex imaging.

The intra-operative duplex imaging was performed with the ATL, Ultramark 9 HDI-3000 model. All imaging was

From the Vascular Surgical Service and Department of Surgery, Tacoma General Hospital, Tacoma, Washington.

Requests for reprints should be addressed to Allen Yu, MD, 314 MLK Jr., WY., Suite 303, Tacoma, Washington 98405.

Presented at the 82nd Annual Meeting of the North Pacific Sur- gical Association, Victoria, British Columbia, November 9-l 1, 1995.

conducted with the Entos CL 10-5 broadband linear array scanhead. Each study was scheduled through the vascular laboratory, and a registered vascular technologist came to the operating room to assist with the exalminations. For each study, a thin layer of acoustic gel was applied to the scanhead and passed through a sterile sleeve with the trans- ducer. The scanhead can be applied directly onto the re- paired vessel(s) and/or graft(s). Duplex imaging samplings were recorded of the common carotid artery, carotid bulb, and proximal and distal sites of the internal and external carotid arteries following the carotid endarterectomy before closing. Patients with abnormal intra-operative carotid du- plex findings subsequently underwent intra-operative an- giogram in order to corroborate the results.‘.-” During iliac artery balloon angioplasty with stent placement cases, post- stent placement imagings of the common femoral arteries were performed. For infra-inguinal bypass cases, intra-op- erative duplex samplings were performed over the proximal and distal anastomosis, the graft itself, and the distal native arteries. Intra-operative carotid and peripheral arterial ste- nosis criteria is the same as pre-operative criteria.12m15

The total time required for each study was recorded and analyzed, and the approximate cost of each study was cal- culated and analyzed.

RESULTS In the carotid endarterectomy procedures (35), 34 pa-

tients (97%) had normal duplex findings. One patient (3%) had evidence of high peak systolic velocity > 250 cc/ set at the proximal internal carotid artery. Subsequently, an intra-operative angiogram was performed to confirm this lesion. The angiogram also demonstrated lstricture at the proximal internal carotid artery. The lesion was subse- quently corrected by vein patch angioplasty. A repeat intra- operative carotid duplex showed normal duplex image find- ings.

An intra-operative angiogram was also performed in two patients (6%) who had normal intra-operative duplex. The first patient developed a transient ischemic event in the operating room upon awakening. The angiogram demon- strated completely normal flow. The patient was transferred to the recovery room and totally recovered.

The other patient apparently developed worsening of a pre-existing neurological deficit (paresis) even though the angiogram demonstrated normal flow. The patient was transferred to the recovery room and subsequently was dis- charged into an extensive physical therapy program. He experienced very good recovery within 6 weeks.

In the iliac artery balloon angioplasty and stem cases ( 12 ), 11 patients (92%) had comparably good results in both in- tra-operative duplex and C-arm post-stent angiograms. The unsuccessful case apparently had multiple tandem lesions

500 0 1996 by Excerpta Medica, Inc. 0002-961 O/96/$1 5.00

All rights reserved. PII SOOO2-961 0(96)00013-X

{INTFIA-0PERATIVE DUPLEX ~IAGIN~/

of the external iliac artery. The most distal lesion was too close to the femoral artery. Subsequently, the decision was made to perform a cross femoral bypass graft.

In the infra-inguinal bypass cases (46), 2 patients (4%) had abnormal duplex findings in the distal native vessel ( < 50% diameter reduction). One graft failed on post-opera- tive day 1, requiring revision of the graft. The other patient is being followed closely as an outpatient.

The average time required for post-endarterectomy intra- operative duplex scanning is 6 minutes, iliac balloon angio- plasty with stent cases require 5 minutes, and infra-inguinal bypass cases take 8 minutes. The intra-operative angiogram or C-arm completion angiogram time is 18 minutes.

The hospital charge for intra-operative duplex examina- tion in post-endarterectomy, iliac artery stents, and infra- inguinal bypasses is approximately $200 per case. Normally, the cost of intra-operative completion angiogram is approx- imately $179 for carotid endarterectomy cases and $2 18 for infra-inguinal bypass cases. If intra-operative C-arm is used for completion angiogram, the hospital charges would be approximately $479 for post-endarterectomy and $518 for iliac stents and infra-inguinal bypass cases. Hospital charges for C-arm are $150 per 15 minutes and with hypaque there is an additional charge of $10 per 100 cc.

CONCLUSION Duplex imaging technique can evaluate the arterial re-

construction anatomically and hemodynamically. How- ever, the intra-operative use of duplex scanning depends on the surgeon’s skill and experience. Therefore, it is strongly encouraged that surgeons are trained with “hands-on” ex- perience and have an efficient technician, such as a regis- tered vascular technologist, to assist them with the study in order to perform the most efficient, reliable studies.

The advantage of intra-operative duplex compared with traditional intra-operative angiogram is that it is less inva- sive, no contrast material is used, the surgeon has the ability to evaluate blood flow hemodynamics and repeat the ex- amination multiple times if necessary, and it is possible to assess the arterial lesion for progression and its resolution after the correction. 1~‘6.‘7

Most importantly, we have demonstrated that the use of intra-operative duplex scanning is less expensive and less time-consuming compared with the use of intra-operative angiogram.

Currently, under the constraints of managed care, cost has become a very important factor. We, as vascular surgeons, patients, hospitals, and third party payers, will all appreciate the more cost-effective and less invasive modality of intra-

operative duplex imaging to evaluate arterial reconstructive surgeries.

REFERENCES 1. Kinney EV, Seabrook GR, Kinney LY, et al. The importance of intra-operative detection of residual flow abnormalities after carotid artery endarterectomy. .I Vast Surg. 1993;17:912-923. 2. Baker WH, Koustas G, Burke K, et al. Intra-operative duplex scanning and late carotid artery stenosis. J Vast Surg. 1994;19:829- 833.

3. Sterpetti AV, Schultz RD, Feldhaus RJ, et al. Natural history of recurrent carotid artery disease. Surg Gynec B Obstet. 1989;168:217-223.

4. Colgan MP, Kingston V, Shanik DG. Stenosis following carotid endarterectomy. .I Curdiovasc Surg. 1985;26:300-302.

5. Ricotta JJ, O’Brien MS, DeWeise JA. Natural history of recurrent and residual stenosis after carotid endarterectomy: implications for post-operative surveillance and surgical management. Surgery. 1992;112:656-663. 6. Flahigan DP, Douglas DJ, Machi J, et al. Intra-operative ultra- sonic imaging of the carotid artery during carotid enclarterectomy.

Surgery. 1986;100:893-898. 7. Lane RJ, Ackroyd N, Appleberg M, et. al. The application of operative ultrasound immediately following carotid endarterectomy. World .I Surg. 1989;11:593-597. 8. Cato R, Bandy KP, Karp D, et al. Duplex scanning after carotid

reconstruction: a comparison of intra-operative and post-operative results. J Vast Technol. 1991;15:61-65. 9. Bandyk DF, Moldenhauer P, Lipchik E, et al. Accuracy of duplex

scanning in the detection of stenosis after carotid enclarterectomy. J VOX Surg. 1988;8:696-702. 10. Zieler RE, Bandyk DF, Thiele BL. Intra-operative assessment of

carotid endarterectomy. J Vast Surg. 1984;1:73-83. 11. Sawchuck AP, Flanigan DP, Machi J, et al. The fate of unre- paired minor technical defects by intra-operative ult-rasonography during carotid endarterectomy. .I Vnsc Surg. 1989;9:671-676. 12. Bandyk DF, Kaebnick HW, Bergamini TM, et al. Hemodyn

amics of in situ saphenous vein arterial bypass. Arch Surg. 1988;123:477-482. 13. Bandyk DF. Intra-operative assessment of arterial reconstruc-

tion utilizing ultrasound. Sem Vusc Surg. 1989;2:75-84. 14. Mills JL, Fujitani RM, Taylor SM. Contribution of routine in- tra-operative completion arteriography to early infra-inguinal bypass patency. Am J Surg. 1992;164:506-5 11,

15. Bandyk DF, Gorostis DM. Intra-operative color flow imaging of “difficult arterial reconstructions”. Video J Color Floes: Imaging. 1991;1:13-20. 16. Bandyk DF, Mills JL, Gahtan V, et al. Intraoperative duplex

scanning of arterial reconstructions: Fate of repaired and unrepaired defects. .I Vast Surg. 1994;20:426-433. 17. Bandyk DK, Zieler RE, Thiela BL. Detection of technical error during arterial surgery by pulsed Doppler spectral analysis. Arch Surg.

1984;119:421-428.

THE AMERICAN JOURNAL OF SURGERYa VOLUME 171 MAY 1996 501