Fig. 29.1
B-mode image of preinjection partially thrombosed pseudoaneurysm
Fig. 29.2
Duplex imaging with to-and-fro flow. Pseudoaneurysm neck marked
Treatment Options
Observation
Several small studies have reported successful closure in more than half of pseudoaneurysms, with observation alone. However, these studies were unable to identify variables to accurately predict which IPA(s) could be safely observed. In a prospective study evaluating the natural history of femoral vascular complications after coronary catheterization, Kresowik et al. observed seven femoral pseudoaneurysms that were less than 3.5 cm, over a 4-week period, with no complications, and 100% thromboses within 4 weeks [2].
In a series of similar size, Kent et al. reported 9 of 16 iatrogenic IPA(s) thrombosed with observation. In this series, larger IPA(s) and patients prescribed anticoagulation required repair more frequently [6].
Toursarkissian et al. reported one of the largest series using duplex surveillance of observed IPA(s) [7]. This series also had strict inclusion criteria for observation of the IPA(s): a maximum sac size less than 3 cm, non-expanding hematoma, pain that was controlled, and no anticoagulation use. Additionally, patients who could not comply with a scheduled follow-up regimen underwent surgical repair and were excluded. Eighty-two IPA(s) were followed at 2-, 4-, 8-, and 12-week intervals. A spontaneous thrombosis rate was observed in 89% of the patients who met the inclusion criteria with no adverse events or circulatory complications. The mean time for spontaneous closure was 23 days, with a mean of 2.6 duplex examinations per patient [7].
Recently, we reviewed a contemporary group of patients that were managed at our institution over a 10-year period by vascular surgeons. The aim of the study was to determine if the natural history of IPAs has changed with the widespread use of newer-generation antiplatelet agents. The series by Toursarkissian was published prior to the marketing of clopidogrel. Not surprising, our results pointed to an increasing failure rate for observation in those patients on poly-antiplatelet medications, with up to 44% requiring treatment, compared to 9% of patients with one antiplatelet agent [8].
Unfortunately, the adoption of an observation policy for IPA(s) is not without concern. Problems with patient follow-up tend to develop, and the cost accrued for a mean of 2.6 duplex examinations per patient approaches $750–1000 in charges.
Ultrasound-Guided Compression (UGC)
In 1991, Fellmeth et al. described a nonoperative technique for thromboses of IPA and arteriovenous fistula. With an overall success rate of 93%, this alternative to open repair was welcomed [9]. Following this initial report, UGC became the first-line treatment of choice for those who were hemodynamically stable and without associated infection or skin necrosis.
This technique includes the use of a linear or curvilinear probe (5 or 7 MHz) to compress the IPA and arrest IPA blood flow. Real-time, duplex, and color Doppler are used to identify the neck of the pseudoaneurysm. Manual compression is subsequently applied to the neck via the transducer, which allows flow through the native artery while preventing flow into the aneurysm sac. Flow is continuously studied during compression. Pressure is maintained for 10-min intervals, at the end of which pressure is slowly released and flow into the pseudoaneurysm is assessed. This is continued until thrombosis, operator fatigue, or patient discomfort occurs. It is not uncommon to require some anxiolytic and analgesic administration to permit adequate compression in those patients with a tender femoral region. Success with this treatment modality generally ranges from 60 to 90% [10–12]. Despite this acceptable success rate, compression times in excess of 1 h can be required, and multiple compression sessions are needed to treat at least 10% of IPA(s).
Factors associated with failed compression have been evaluated in multiple previous publications. Ongoing anticoagulation has been shown in many series to significantly reduce successful compression, as reported by Coley et al. and Eisenburg et al. [11, 13]. They describe failure rates of 38% and 70%, respectively, in anticoagulated patients, whereas failure rates in the groups without concurrent anticoagulation were 5 and 26%. In addition, 75% of those in Coley’s series ultimately had their anticoagulation discontinued and underwent repeat UGC with successful thrombosis. Several other series have shown similar results.
In contrast, Dean et al. found a 73% success rate of UGC in 77 patients with uninterrupted anticoagulation, with seven patients requiring multiple compressions (12.5%) to induce sustained thrombosis. The only factor found in this study that influenced the success of UGC was the size of the pseudoaneurysm [14]. Larger pseudoaneurysms have been shown, in most series, to have less success with UGC than smaller ones. In addition to Dean and Coley, Eisenburg also showed increased success with compression in patients with smaller pseudoaneurysms. This was also exemplified by Coley et al., achieving a 100% success rate in pseudoaneurysms <2 cm but only a 67% success in those between 4 and 6 cm. Although it seems intuitive that a shorter tract length and larger neck diameter would have less success with compression, this has not been widely reported. Diprete and Cronan did report a short tract length (<5 mm) had unfavorable compression outcomes; however, this study was limited by a sample size of only 12 patients [15].
Complications following UGC can include arterial or venous thrombosis. Case reports of aneurysm rupture have also been reported following UGC. Eisenberg et al. reported six complications following UGC, including acute enlargement or rupture requiring emergent surgery [13]. However, in general, complications with UGC are infrequent. Successful thrombosis occurs at an acceptable rate, but limitations, including lengthy procedure times, local patient discomfort, and newer methods, have replaced this treatment as the first-line approach to management of iatrogenic pseudoaneurysms.
Ultrasound-Guided Thrombin Injection (UGTI)
In 1986, Cope and Zeit described a technique for ultrasound-guided percutaneous injection of bovine thrombin into a pseudoaneurysm sac with successful thrombosis [16]. Although an appealing method for handling IPA, this technique took over a decade to be widely accepted to replace UGC. During that time interval, several studies were published comparing UGC to ultrasound-guided thrombin injection [17–23] (Table 29.1). The success rates for ultrasound-guided thrombin injection have been uniformly superior, including a small prospective randomized trial by Lonn et al. [23]. In addition to high immediate technical success rates, the subsequent recurrence rate is very low [24–38].
Table 29.1
Ultraso und-guided compression (UGC) versus ultrasound-guided thrombin injection (UGTI)
Reference | N (UGC)/(UGTI) | Success (%) (UGC)/(UGTI) |
|---|---|---|
Weinmann et al. [17] | 30/33 | 87/100 |
Gorge et al. [18]a | 36/30 | 17/93 |
Taylor et al. [19] | 40/29 | 63/93 |
Stone et al. [20] | 47/27 | 57/96 |
Paulson et al. [21] | 281/26 | 74/96 |
Khoury et al. [22] | 189/131 | 75/96 |
Lonn et al. [23]b | 15/15 | 40/100 |
Technical Tips
The procedure can be performed at bedside or in the vascular laboratory.
Some clinicians use local anesthetic; however, with experience, single punctures can be achieved with the spinal needle alone. The groin is prepped with antiseptic and a sterile probe cover is recommended.
A 1-ml syringe and spinal needle (20–22 gauge) is used to administer the bovine thrombin (100–1000 units/ml).
Using B-mode imaging, the needle tip is visualized and directed into the IPA sac (Fig. 29.3). The clinician should take care to keep the needle tip just inside the capsule and as far from the IPA neck as technically possible. This minimizes the chance of thrombin administration into the neck and, ultimately, into the native circulation.
Under duplex visualization, the sac is injected at 0.1-ml increments until successful obliteration of flow is achieved, which is confirmed by color Doppler examination.
After successful thrombosis , the native circulation is reassessed, including the distal pedal pulses, and compared to pre-procedural (Fig. 29.4).
Following successful thrombosis, bed rest is typically recommended for a period of 4–6 h.
Fig. 29.3
Needle tip located away from pseudoaneurysm neck
Fig. 29.4
Successful duplex imaging of thrombosis pseudoaneurysm. Absent color flow visualized
Complications following thrombin injection are reported infrequently. The most feared complications are arterial thrombosis and distal embolization. Distal embolization has occurred in less than 1% of the reviewed literature, with some authors noting improved arterial perfusion spontaneously. Others have been successfully treated with intra-arterial thrombolytic therapy or surgical thrombectomy. Limited evidence suggests that distal embolization is associated with short and wide pseudoaneurysm necks.
Other complications, seen only in case reports, include allergic reactions to bovine thrombin with severity ranging from generalized urticaria to anaphylaxis. Infection after injection has also been reported occasionally, and one case of rupture was identified in a complete literature review.
Experience from Our Institution
As a high-volume cardiac and peripheral intervention center, we have extensive experience with post-catheterization pseudoaneurysms managed by our vascular surgery group. We previously reported our early results of duplex-guided thrombin injection versus UGC [20]. With a success rate of only 57% for compression therapy , as opposed to a 97% success rate with duplex-guided thrombin injection, compression therapy has been nearly abandoned at our facility over the past decade.
Further experience from our group was presented at the Society of Vascular Ultrasound Annual Meeting in June of 2004. Ninety-seven percent of patients (n = 82) with iatrogenic pseudoaneurysms, of which 12 were complex, were successfully treated with UGTI. The mean number of ultrasounds per patient was three and generally included diagnostic, treatment, and follow-up examinations. Upon evaluation of this routine, we found only 5% of the follow-up ultrasounds could be deemed clinically significant. Two pseudoaneurysms recurred after successful thrombosis, and two new pseudoaneurysms were found that had not been previously detected, both of which were less than 2.5 cm. With such a low yield from follow-up duplex examinations, we recommended follow-up ultrasound only in symptomatic patients. We also analyzed the recurrence rate with over 600 iatrogenic pseudoaneurysms reported in the literature, with a 3.2% recurrence rate after successful duplex-guided thrombin injection (Table 29.2).
Table 29.2
Literature review of PSA recurrences
Author | Number of successful initial DGTI | Number of recurrence at follow-up |
|---|---|---|
Liau et al. [24] | 5 | 0 (24 h) |
Kang et al. [25] | 20 | 0 (1–4 days) |
Lennox et al. [26] | 30 | 0 (1 day and 3 weeks) |
Brophy et al. [27] | 15 | 0 (1 week) |
Sackett et al. [28] | 29 | 0 (24 h) |
Pezzullo et al. [29] | 23 | 1 (24 h) |
Paulsen et al. [21] | 23 | 0 (24 h) |
Tamim et al. [30] | 10 | 0 (1 and 3 weeks) |
La Perna et al. [31] | 66 | 3 (24 h) |
Calton et al. [32] | 52 | 2 (24 h) |
Sheiman et al. [33] | 50 | 0 (within 10 days) |
Olson et al. [34] | 17/15 | 1 (24 h)/1 (1 week) |
Friedman et al. [35] | 40 | 0 (24 h)/1 (1 week)
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