Repair of pseudoaneurysms via ultrasound-guided compression.
Pseudoaneurysms occur when a sealing clot fails to form at the puncture site. A hole in the vessel wall remains open, and as blood flows out into the surrounding tissues it becomes encapsulated, forming a PA. Blood continues to flow into the PA via a communicating tract. If untreated, spontaneous rupture, resulting in uncontrolled hemorrhage, can occur.[2,10,11]
Pseudoaneurysms usually are discovered shortly after catheterization during follow-up patient assessment, but they may not present until days or weeks after the arterial catheterization procedure. Coley et al report initial discovery of PA up to 99 days following catheter removal.
There is a suspicion of PA when a patient complains of pain, has diminished or absent pulses or develops limb ischemia. A patient also can present with thromboembolus or a pulsatile mass with an audible bruit or murmur.
A pseudoaneurysm usually is diagnosed by physical exam and confirmed with sonography. The characteristic sonographic appearance of a PA is a hypoechoic or anechoic, pulsatile mass connected to an artery by a tract. (See Fig. 1.) Compression of a major vessel often is evident if the PA is large. (See Fig. 2.)
[Fig. 1 AND 2 ILLUSTRATION OMITTED]
Blood flows into the PA during systole, when the velocity of flow is the greatest. During diastole, when the flow is sluggish, the blood flow is in the opposite direction. (See Fig. 3.) This bidirectional flow is seen on color Doppler as a swirling pattern, as shown in Fig. 4, and often is referred to as a "to and fro" pattern with pulsed wave Doppler.[10,12] (See Fig. 5.) This flow pattern is similar to the "systolic jet" and "diastolic washout" signs that are observed during angiography. The signs of bidirectional flow are reliable indicators for the detection of a PA when using color flow Doppler ultrasound.[10,13]
[Fig. 3-5 ILLUSTRATION OMITTED]
Prompt surgical intervention has been the standard for treating PAs, although they have been known to thrombose spontaneously. In 1992 Paulson et al evaluated color Doppler sonographic characteristics of PA formation that might help predict which PAs would thrombose without intervention. Their study of 24 PAs concluded that there was no way to sonographically predict thrombus formation. Because criteria have not yet been established that can predict which PA will close spontaneously, immediate treatment is recommended. Although emergency vascular surgery is sometimes still performed to correct PA, many physicians are first choosing to try a noninvasive interventional treatment called ultrasound-guided compression repair.[1,15-8]
Overview of UGCR
Ultrasound-guided compression repair (UGCR) obliterates a PA through the application of direct pressure over the communicating tract. The pressure must be great enough to block blood flow and result in thrombus formation. The technique is simple and can be performed using only manual pressure with an ultrasound transducer. A C-clamp device, which allows mechanical compression, also has been successful when used for compression therapy (Clamp Ease, Pressure Product Inc., San Pedro, Calif).[8,19]
Compression therapy begins with an initial sonogram using a 5 MHz or 7.5 MHz linear array or sector transducer.[2,5,6,8] The choice of transducer type and frequency depends on the size of the patient, the location of the lesion with regard to the skin surface and the availability of the equipment. Real-time, duplex or Doppler ultrasound may be used to assess vessel anatomy.
The skin puncture site for the arterial catheterization is used as a guideline for the initial sonogram.[6,8] Due to the cephalad angle of incidence of the needle during arterial puncture, a PA typically will be found superior to the skin puncture site.
The suspected PA is scanned in both longitudinal and transverse planes. Measurements are taken of any abnormal pathology that is identified. All vessels in the general vicinity of the PA must be identified to prevent inadvertent compression of any native vessels.
Once a suspected PA has been confirmed on an initial ultrasound, the procedure, risks and benefits of UGCR are explained to the patient. After consent is given, baseline blood pressure and pulses distal to the PA are recorded. The tract of the PA is reidentified and, using the scanning surface of the transducer, compression is applied. Blood flow in the tract and in the native vessels is monitored with the transducer during the compression phase of the procedure. Direct downward pressure is applied to the tract to stop blood flow into the PA, but not enough pressure is used to disrupt the blood flow in the adjacent native vessel.[2,5,17] (See Fig. 6.)
[Fig. 6 ILLUSTRATION OMITTED]
The PA tract is repeatedly compressed at timed intervals. A compression cycle oil, 10 minutes has been suggested, because this interval gives the patient and the operator a break during the procedure. After 10 minutes, the transducer is slowly released and the site is scanned to determine if there is any residual blood flow. If flow is observed, another 10-minute compression is applied immediately. These compression cycles continue until the flow in the tract of the PA stops completely. Although compression times vary, the total procedure time averages about 30 minutes, or three cycles.
Another option is to use longer compression times of 15 minutes to 30 minutes, decreasing the number of cycles needed. These longer times are as successful as the shorter serial compressions, but their use is limited by patient cooperation and operator fatigue.[2,21]
When the C-clamp is used for compression, there are two procedural alternatives. In the first option, compression is applied by the clamp and the transducer is manually operated to monitor blood flow. In the second option, the ultrasound transducer is mounted on the C-clamp. This alternative allows the transducer to remain in a fixed position, applying the compression while simultaneously monitoring blood flow. In either case, the operator can monitor the compression without experiencing fatigue.
Regardless of which method is used, the operator must be consistent in the amount of compressive force used to occlude blood flow. If the C-clamp is used to hold the transducer, both should be adequately secured because any shift in the apparatus could allow fresh blood to flow back into the PA.
Once external compression is successfully completed, the patient remains on bedrest for 3 to 6 hours with the affected area immobilized.[5,22] If possible, anticoagulant drug therapy is withheld during this time. The PA cavity should form a hematoma that will resolve in a few days to weeks, depending on the original size of the PA. (See Fig. 7.) In the first 24 to 72 hours following successful closure of the lesion, the patient should receive a follow-up sonogram to ensure the site remains closed. Additional follow-up exams can be performed at the discretion of the patient's attending physician.
[Fig. 7 ILLUSTRATION OMITTED]
Ultrasound-guided compression repair has decreased the need for surgery to correct pseudo-aneurysms. Studies have shown that UGCR has a high rate of success, ranging from 73% to 94% .[15-18] Developed in 1991 and considered an experimental procedure for several years, it has only been since 1995 that reimbursement has been allowed for UGCR.
Today, research is focusing on identifying factors that could predict the success or limitations of UGCR. Variables that affect the outcome of UGCR are complexity, the use of anticoagulant therapy and the size and age of the PA.
Early studies by Fellmeth et al suggested that UGCR was contraindicated in patients with injuries older than 1 month because by then the PA has a mature endothelial lining and a tough fibrous capsule.[22,23] However, Cox's study of 100 PAs that were 1 to 35 days old and Coley's study of 117 PAs that were 1 to 99 days old indicate that the time after injury does not significantly affect the outcome, although the compression time needed for successful treatment is longer when a PA is older than 2 weeks. These researchers also evaluated the effects of size and complexity of a PA and found no significant effect on successful compression treatment, although larger PAs required more compression time for complete thrombosis to occur.[1,18]
Initially, researchers believed the use of anticoagulant drug therapy would adversely affect the success rate of UGCR. However, studies have shown that UGCR can be successfully performed on patients who take anticoagulant drugs, as well as those who do not take them.[13-17,21] (See Table 1.) Again, compression times might be longer or second attempts may be needed, but success is possible.
Table 1 UGCR Success Rate With and Without Anticoalulant Therapy (Either Warfarin or Heparin) Author Number of Success of UGCR of PSAs Without Study Studied Anticoagulant Theraphy Coley(*) 117 71/75 (95%) Hajarizadeh 57 42/42 (100%) Dean([dagger]) 77 -- Currie 9 4/5 (80%) Cox 100 64/65 (98%) Author Success of UGCR of With Overall Success Rate Study Anticoagulant Theraphy of UGCR Coley(*) 32/37 (86%) 109/117 (93%) Hajarizadeh 9/15 (60%) 51/57 (89%) Dean([dagger]) 56/77 (73%) 56/77 (73%) Currie 4/4 (100%) 8/9 (89%) Cox 30/35 (86%) 94/100 (94%)
(*) Information about anticoagulant theraph was not available on 14 patients.
(**) All unsuccessful UGCR patients were on heparin.
([dagger]) All patients were on uninterrupted therapy.
Although UGCR is feasible in most cases, there are situations where it should not be attempted. Obliteration by compression is contraindicated for PAs that occur at a site of surgical anastomosis. These lesions may be the result of infection and have the potential to rupture. Other contraindications include infection at the catheterization site, severe tenderness and pain, nerve impairment and skin necrosis. If a PA of the femoral artery is located above the inguinal ligament, UGCR should not be attempted because there is an increased risk of hemorrhage and rupture.
Because there is a potential threat for serious complications, some recommendations have been suggested to ensure the safety of the patient. Before beginning UGCR, a vascular surgeon should be made aware that the procedure is occurring, so that surgical intervention can take place if necessary. An IV line should be established prior to the start of the procedure. Finally, there should be at least one other person in the room with the operator in the event of an emergenCy.[24,25]
In the absence of any of the indicated risk factors, it has been suggested that UGCR be attempted on all feasible PAs before taking a surgical approach.[1,24,26] Even if UGCR is unsuccessful or complications occur, subsequent surgical intervention would not be compromised.
Compression repair is a cost-effective treatment when compared with surgery, since patient stay is shortened and postsurgical complications are avoided. In addition, because UGCR is noninvasive, a patient recovers faster than with open surgical repair of the lesion.
With the rise in the number of arterial catheterizations being performed, there also is a rise in the incidence of PA formation. Noninvasive treatment with UGCR is a valuable and successful method of repair for this type of arterial injury. Ultrasound-guided compression repair is not intended to replace all surgical repairs of PAs, but it can be used as a safe, reliable, cost-effective alternative to surgery in most cases. The ability to surgically repair a lesion is still an option if UGCR is not successful or if complications develop.
[1.] Coley BD, Roberts AC, Fellmeth BD, Valji K, Bookstein JJ, Hye RJ. Postangiographic femoral artery pseudoaneurysms: further experience with US-guided compression repair. Radiology. 1995;194:307-311.
[2.] Fellmeth BD, Buckner NK, Ferreira JA, Rooker RT, Parsons PM, Brown PR. Postcatheterization femoral artery injuries: repair with color flow US guidance and C-clamp assistance. Radiology. 1992,182:570-572.
[3.] Kussmaul WG III, Buchbinder M, Whitlow PL, et al. Rapid arterial hemostasis and decreased access site complications after cardiac catheterization and angioplasty: results of a randomized trial of a novel hemostatic device. J Am Coll Card. 1995;25:1685-1692.
[4.] Lumdsen AB, Miller JM, Kosinski AS, et al. A prospective evaluation of surgically treated groin complications following percutaneous cardiac procedures. Am Surgeon. 1994;60(2):132-137.
[5.] Sorrell KA, Feinberg RL, Wheeler JR, et al. Color-flow duplex-directed manual occlusion of femoral false aneurysms. J Vasc Surg. 1993;17:571-577.
[6.] Feld R, Patton GM, Carabasi RA, Alexander A, Merton D, Needleman L. Treatment of iatrogenic femoral artery injuries with ultrasound-guided compression. J Vasc Surg. 1992;16:832-840.
[7.] Kreipke DL, Holden RW, Wass JL. Two angiographic signs of pseudoaneurysms: systolic jet and diastolic washout. Radiology. 1982;114:79-82.
[8.] Agarwal R, Agarwal SK Roubin GS, et al. Clinically guided closure of femoral arterial pseudoaneurysms complicating cardiac catheterization and coronary angioplasty. Catheterization and Cardiovascular Diagnosis. 1993;30:96-100.
[9.] Khoury M, Batra S, Berg R, Rama K. Duplex-guided compression of iatrogenic femoral artery pseudoaneurysms. Am Surgeon. 1994;60:234-237.
[10.] Johns HP, Pupa LE Jr, Bailey SR. Spontaneous thrombosis of iatrogenic femoral artery: documentation with color Doppler and two-dimensional ultrasonography. J Vasc Surg. 1991;14:24-29.
[11.] Smith MB, Profitt RD, Valentine MM. Traumatic pseudoaneurysm. Emergency Med. 1989;21:147,150.
[12.] Abu-Yousef MM, Wiese JA, Shamma AR. The "to and fro" sign: duplex Doppler evidence of femoral artery pseudoaneurysm. AJR. 1988;150: 632-634.
[13.] Sheikh KH, Adams DB, McCann R, Lyerly HK, Sabiston DC, Kisslo J. Utility of Doppler color flow imaging for identification of femoral arterial complication of cardiac catheterization. Am Heart J. 1989;117:623-635.
[14.] Paulson EK, Hertzberg BS, Paine SS, et al. Femoral artery pseudoaneurysms: value of color Doppler sonography in predicting which ones will thrombose without treatment. AJR. 1992;159:1077-1081.
[15.] Hajarizadeh H, La Rosa CR, Cardullo P, Rohrer MJ, Cutler BS. Ultrasound guided compression of iatrogenic femoral pseudoaneurysm failure, recurrence, and long-term results. J Vasc Surg. 1995;22:425430.
[16.] Dean SM, Olin JW, Piedmonte M, Grubb M, Young JR. Ultrasound-guided compression closure of postcatheterization pseudoaneurysms during concurrent anticoagulation: a review of seventy-seven patients. J Vasc Surg. 1996;23:28-34.
[17.] Currie P, Turnbull CM, Shaw TR. Pseudoaneurysm of the femoral artery after cardiac catheterisation: diagnosis and treatment by manual compression guided by Doppler color flow imaging. Br Heart J. 1994;72:80-84.
[18.] Cox GS, Young JR, Gray BR, Grubb MW, Hertzer NR. Ultrasound-guided compression repair of postcatheterization pseudoaneurysms: results of treatment in one hundred cases. J Vasc Surg. 1994; 19:683-686.
[19.] Steinsapir ES, Coley BD, Fellmeth BD, Roberts AC, Hye RJ. Selective management of iatrogenic femoral artery injuries. J Surg Research. 1993;55(1):109-113.
[20.] Helvie MA, Rubin JM, Silver TM, Kresowik TF. The distinction between femoral artery pseudoaneurysms and other causes of groin masses: value of duplex Doppler sonography. AJR. 1988;150:1177-1180.
[21.] Schwend RB, Hambsch KP, Kwan KY, Boyajain RA, Otis SM. Color duplex sonography guided obliteration of pseudoaneurysm. J Ultrasound Med. 1993;12:609-613.
[22.] Fellmeth BD, Roberts AC, Bookstein. JJ, et al. Postangiographic femoral artery injuries: nonsurgical repair with US-guided compression. Radiology. 1991;178:671-675.
[23.] Fellmeth BD, Baron SB, Brown PR, et al. Repair of postcatheterization femoral pseudoaneurysms by color flow ultrasound guided compression. Am Heart J. 1992;122:547-551.
[24.] Moote DJ, Hilborn MD, Harris KA, Elliott JA, MacDonald AC, Foley JB. Postarteriographic femoral pseudoaneurysms: treatment with ultrasound-guided compression. Ann Vasc Surg. 1994;8(4):325-331.
[25.] Dol JA, Reekers JA, Kromhout JG. Rupture of pseudoaneurysm during attempted US-guided compression repair. Radiology. 1992;185:284.
[26.] Schaub F, Theis W, Heinz M, Zagel M, Schomig A. New aspects in ultrasound-guided compression repair of postcatheterization femoral artery injuries. Circulation. 1994;90:1861-1865.
Kathleen G. Benassi, B.S., R. T.(R), is radiology manager at Putnam County Hospital, Greencastle, Ind. Linda A. Cox, MS., R. T.(R), is an assistant professor in the Department of Radiologic Sciences, School of Allied Health Sciences, at Indiana University Medical Center, Indianapolis, Ind. Bruce W. Long, M. S., R. T. (R), is an associate professor in the Department of Radiologic Sciences, School of Allied Health Sciences, at Indiana University Medical Center, Indianapolis, Ind.
The authors would like to thank Gary Becker, M.D., of Baptist Hospital, Miami, Fla., for his help in providing images for this article.
Reprint requests may be sent to the American Society of Radiologic Technologists, Publications Department, 15000 Central Ave. SE, Albuquerque, NM 87123-3917.
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|Author:||Benassi, Kathleen G.; Cox, Linda A.; Long, Bruce W.|
|Date:||Sep 1, 1997|
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