Modified Balloon-Assisted Thrombin Injection via Distal Access for Complex Femoral Pseudoaneurysms

Abstract

Background

Iatrogenic femoral artery pseudoaneurysms are a recognized complication after catheterization procedures. Although ultrasound-guided thrombin injection is the mainstay of treatment, pseudoaneurysms with wide necks or complex anatomy pose treatment challenges.

Case Summary

We present a 6-case series in which a modified balloon-assisted thrombin injection (BATI) technique was employed using retrograde pedal or anterograde radial access in iatrogenic femoral artery pseudoaneurysms with wide-neck morphology or procedural risk factors. Distal access permitted simultaneous angiographic visualization and balloon occlusion during thrombin injection. All patients achieved complete thrombosis without complications or recurrence over 6 to 9 months of follow-up.

Conclusions

Modified BATI via distal access offers a minimally invasive alternative for select complex pseudoaneurysms when traditional approaches are less favorable. Future studies are needed to evaluate long-term outcomes.

Graphical Abstract

Iatrogenic femoral artery pseudoaneurysms (IFAPs) complicate 0.2% to 8% of catheterizations.¹ Risk factors include atherosclerosis, older age, obesity, prolonged procedures, failed closures, and anticoagulation.^1,2 Untreated cases can cause morbidity through embolization, compression, and rupture.²

Take-Home Messages

• •Modified BATI via PTA or radial access avoids additional femoral puncture in high-risk PSA cases.
• •Distal access provides real-time angiographic guidance for balloon placement and enhanced control during thrombin injection.
• •Technical success and safety profile in this series support its consideration as a second-line percutaneous option.

Traditional approaches include ultrasound-guided compression repair (UGCR) and surgical repair, both with limitations. Minimally invasive alternatives such as endovascular coiling and ultrasound-guided thrombin injection (UGTI) show 93% to 100% success rates,² but wide-neck pseudoaneurysms risk thrombin leakage.

Although no definitive width universally defines a wide-neck pseudoaneurysm, a common femoral artery (CFA) pseudoaneurysm is typically considered to have a wide neck when the neck diameter is >5 mm according to Yang et al,² although the American College of Cardiology designates >4 mm as wide neck width. The wide-neck morphology significantly complicates pseudoaneurysm management, often necessitating open surgical intervention rather than minimally invasive techniques for successful repair.

Percutaneous balloon-assisted ultrasound-guided thrombin injection (BATI), introduced by Vowels et al,³ combines balloon occlusion with thrombin injection through contralateral femoral access, offering a safe and minimally invasive option for these complex cases. We present 6 cases using modified BATI via distal access using either retrograde posterior tibial artery (PTA) or anterograde radial artery approaches. This case series demonstrates the feasibility of our technique for treating femoral pseudoaneurysms with varying anatomies, where traditional UGTI might be contraindicated or risks failure.

Patient 1

An 85-year-old woman underwent subclavian intervention via right CFA. The right groin was closed with Angio-Seal (Terumo Interventional Systems). Five days later, the patient developed a large pulsatile mass, and color Doppler ultrasound (CDUS) demonstrated a 15.86 × 6.64 mm wide-neck pseudoaneurysm with 5.50-mm opening displaying classic yin-yang flow. After failed UGCR, she underwent balloon-assisted thrombin embolization via right pedal access. Retrograde 7.0-mm balloon provided tamponade, while 300 IU of thrombin was injected into the pseudoaneurysm sac with ultrasound guidance (Figures 1A to 1D). There was no recurrence on computed tomography angiography (CTA) after 24 hours or at 8-month follow-up (Table 1).

Figure 1.

Imaging Results for Patient 1

(A) CDUS demonstrating a 15.86 × 6.64 mm wide-neck pseudoaneurysm with a 5.50-mm opening displaying classic yin-yang flow at the right CFA. (B) Angiogram via right PTA access of right CFA pseudoaneurysm before ultrasound-guided BATI. (C) CDUS after BATI via retrograde right PTA access demonstrated complete thrombosis; 300 IU of thrombin was injected into the pseudoaneurysm sac. (D) Angiogram after BATI showing resolution of wide-necked pseudoaneurysm with preserved flow to the native CFA. A 7.0-mm balloon provided tamponade during ultrasound-guided thrombin injection. Results were sustained at the 8-month follow-up. BATI = balloon-assisted thrombin injection; CDUS = color Doppler ultrasound; CFA = common femoral artery; PTA = posterior tibial artery.

Table 1.

Clinical Summary and Overview of Included Patients

Patient	Initial Procedure	Arteriotomy Closure Mechanism	Pseudoaneurysm Size (mm)	Neck Size of Pseudoaneurysm (mm)	Balloon Size	Thrombin Units Injected	Follow-Up length	Result
Patient 1 85-yr-old woman	Left subclavian artery stenting via right CFA	Angio-Seal	15.86 × 6.64	5.50 mm	7.0 mm	300 IU	8 mo	Complete resolution
Patient 2 73-yr-old man	Right coronary artery stenting via right CFA	Mynx	13.78 × 8.84	6.00 mm	6.0 mm	195 IU	9 mo	Complete resolution
Patient 3 53-yr-old woman	Bypass angiography via right CFA	FemoStop	12.89 × 20.05	5.50 mm	7.0 mm	250 IU	6 mo	Complete resolution
Patient 4 59-yr-old woman	Left common iliac artery stenting via bilateral CFA	Mynx	12.74 × 6.71	5.94 mm (left CFA)	6.0 mm	360 IU	72 h	Complete resolution
Patient 5 81-yr-old woman	TAVR via left CFA	Unknown	19.50 × 16.70	6.29 mm	7.0 mm	260 IU	3 mo	Complete resolution
Patient 6 60-yr-old woman	Right proximal SFA stenting via left CFA	Angio-Seal	18.50 × 9.98	6.95 mm	7.0 mm	292 IU	2 mo	Complete resolution

Clinical summary and overview of 6 patients who underwent modified balloon-assisted thrombin injection via distal access for wide-neck femoral pseudoaneurysms.

CFA = common femoral artery; SFA = superficial femoral artery; TAVR = transcatheter aortic valve replacement.

Patient 2

A 73-year-old man underwent percutaneous coronary intervention via the right CFA. A Mynx vascular closure device (Cordis) was used. Overnight, the patient developed a large right groin hematoma. CTA of the abdomen/pelvis showed active bleeding with extension into the right lower extremity. Ultrasound showed a 13.78 × 8.84 mm pseudoaneurysm with 6.00 mm–wide neck. Despite both UGCR and compression with FemoStop device (Abbott), the hematoma expanded. The patient underwent BATI via pedal access. Retrograde 6.0-mm balloon provided initial tamponade, while 195 IU of thrombin was injected into the pseudoaneurysm under ultrasound guidance (Figures 2A to 2D). There was no recurrence on CTA postprocedure or at 9-month follow-up (Table 1).

Figure 2.

Imaging Results for Patient 2

(A) CDUS demonstrating a 13.78 × 8.84 mm wide-neck pseudoaneurysm with a 6.00-mm opening displaying classic yin-yang flow at the right CFA. (B) Angiogram via right PTA access of right CFA pseudoaneurysm before ultrasound-guided BATI. (C) CDUS after BATI via retrograde right PTA access demonstrated complete thrombosis; 195 IU of thrombin was injected into the pseudoaneurysm sac. (D) Angiogram after BATI showing resolution of wide-necked pseudoaneurysm with preserved flow to the native CFA. A 6.0-mm balloon provided tamponade during ultrasound-guided thrombin injection. Results were sustained at the 9-month follow-up. Abbreviations as in Figure 1.

Patient 3

A 53-year-old woman underwent coronary angiography via right CFA. An Angio-Seal closure device was used. Five days postprocedure, ultrasound revealed a 12.89 × 20.05 mm pseudoaneurysm with 5.50 mm–wide neck confirmed by CDUS. Both UGCR and FemoStop compression failed. Definitive treatment consisted of balloon-assisted thrombin embolization using a retrograde 7.0-mm balloon via right PTA access. Complete thrombosis was achieved with 250 IU of thrombin injected into the pseudoaneurysm sac under ultrasound guidance (Figures 3A to 3D). There was no recurrence on CTA postprocedure or on CDUS at 6-month follow-up (Table 1).

Figure 3.

Imaging Results for Patient 3

(A) CDUS demonstrating a 12.89 × 20.05 mm wide-neck pseudoaneurysm with a 5.50-mm opening displaying classic yin-yang flow at the right CFA. (B) Angiogram via right PTA access of right CFA pseudoaneurysm before ultrasound-guided BATI. (C) CDUS after BATI via retrograde right PTA access demonstrated complete thrombosis; 250 IU of thrombin was injected into the pseudoaneurysm sac. (D) Angiogram after BATI showing resolution of wide-necked pseudoaneurysm with preserved flow to the native CFA. A 7.0-mm balloon provided tamponade during ultrasound-guided thrombin injection. Results were sustained at the 6-month follow-up. Abbreviations as in Figure 1.

Patient 4

A 59-year-old woman on oral anticoagulation and obesity (BMI >35.0 kg/m²) underwent revascularization via bilateral CFA access. A MYNX vascular closure device was applied to each access site. The following morning, the patient developed a large hematoma around the left groin, rapidly progressing to hemorrhagic shock. CDUS confirmed a 12.74 × 6.71 mm pseudoaneurysm with 5.94 mm–wide neck in the left CFA with classic yin-yang pattern of filling. As the patient was unstable and immediate intervention was necessary, the standard UGCR technique was bypassed. The right PTA was accessed under ultrasound guidance, and a 6.0-mm balloon was used for tamponade of the left CFA pseudoaneurysm, followed by 360 IU thrombin injection under ultrasound visualization. Postprocedure angiography demonstrated complete thrombosis of the pseudoaneurysm while confirming patency of native arteries (Figures 4A to 4D). Ultrasound at 72-hour follow-up showed no recurrence (Table 1).

Figure 4.

Imaging Results for Patient 4

(A) CDUS demonstrating a 12.74 × 6.71 mm wide-neck pseudoaneurysm with a 5.94-mm opening displaying classic yin-yang flow at the left CFA. (B) Angiogram via right PTA access of left CFA pseudoaneurysm before ultrasound-guided BATI. (C) CDUS after BATI via retrograde right PTA access demonstrated complete thrombosis; 360 IU of thrombin was injected into the pseudoaneurysm sac. (D) Angiogram of after BATI showing resolution of wide-necked pseudoaneurysm with preserved flow to the native CFA. A 6.0-mm balloon provided tamponade during ultrasound-guided thrombin injection. Results were sustained at the 72-hour follow-up. Abbreviations as in Figure 1.

Patient 5

An 81-year-old woman on oral anticoagulation presented with pseudoaneurysm arising from the left CFA site used for recent TAVR. CDUS confirmed 19.50 × 16.70 mm pseudoaneurysm with 6.29 mm–wide neck demonstrating classic yin-yang flow. After failed UGCR, she underwent BATI via radial access because of a nonhealing wound over the anterior aspect of the right ankle. A 7.0-mm balloon was positioned at the neck of the pseudoaneurysm and inflated to achieve hemostasis then 260 IU thrombin was injected into the pseudoaneurysm neck under ultrasound visualization. Postprocedure ultrasound confirmed occlusion of the pseudoaneurysm (Figures 5A to 5D). There was no recurrence on CTA postprocedure or on CDUS at 3-month follow-up (Table 1).

Figure 5.

Imaging Results for Patient 5

(A) CDUS demonstrating a 19.50 × 16.70 mm wide-neck pseudoaneurysm with a 6.29-mm opening displaying classic yin-yang flow at the left CFA. (B) Angiogram via right radial access of left CFA pseudoaneurysm before ultrasound-guided BATI. (C) CDUS after BATI via anterograde right radial access demonstrated complete thrombosis; 260 IU of thrombin was injected into the pseudoaneurysm sac. (D) Angiogram after BATI showing resolution of wide-necked pseudoaneurysm with preserved flow to the native CFA. A 7.0-mm balloon provided tamponade during ultrasound-guided thrombin injection. Results were sustained at the 3-month follow-up. Abbreviations as in Figure 1.

Patient 6

A 60-year-old woman underwent revascularization of the right lower extremity via left CFA, closed with Angio-Seal. The next day, she developed dull abdominal pain, and CTA abdomen/pelvis confirmed retroperitoneal bleed and pseudoaneurysm. CDUS confirmed 18.50 × 9.98 mm pseudoaneurysm with 6.95 mm–wide neck with classic yin-yang flow. Both FemoStop and UGCR failed. Right radial access was obtained, and a 7.0-mm balloon was positioned at the neck of the left CFA for balloon tamponade. Under ultrasound guidance, 292 IU thrombin was injected in the neck of the pseudoaneurysm. Postprocedure ultrasound confirmed occlusion of the pseudoaneurysm (Figures 6A and 6B, Videos 1 to 3). There was no recurrence on postprocedure CTA or on CDUS at 2-month follow-up (Table 1).

Figure 6.

Imaging Results for Patient 6

(A) CDUS demonstrating an 18.50 × 9.98 mm wide-neck pseudoaneurysm with a 6.95-mm opening displaying classic yin-yang flow at the left CFA. (B) CDUS after ultrasound-guided BATI via anterograde right radial access demonstrated complete thrombosis; 292 IU of thrombin was injected into the pseudoaneurysm sac. Abbreviations as in Figure 1.

Discussion

This case series supports growing evidence for the efficacy and safety of percutaneous BATI in managing complex IFAPs. Although studies often cite a neck width of >4 to 6 mm as a wide-neck pseudoaneurysm, the definition of a complex pseudoaneurysm is more nuanced. Complexity arises from a confluence of factors—short pseudoaneurysm tract, adjacent hematoma, bifurcation proximity, multiple lobes, deep location, branch involvement, arteriovenous fistula, and intraluminal thrombus. A uniformly wide neck or tract extending from the pseudoaneurysm sac to the donor artery typically poses greater technical challenges. Advanced age, obesity, failed device closure, hemodynamic instability, and ongoing anticoagulation and coagulopathy contribute to a more complex pseudoaneurysm profile.² All 6 patients in this case series achieved complete thrombosis of their wide-neck pseudoaneurysms without complications using the modified distal peripheral approach, despite complex risk factors.

Patient 4 warrants specific mention. This individual presented with hypotension and expanding hematoma but only a small pseudoaneurysm visible on imaging. We postulate that an occult retroperitoneal extension or venous injury may have contributed to hemodynamic instability. Nevertheless, our approach successfully addressed the visible pseudoaneurysm and stabilized the patient, supporting the adjunctive value of BATI even in ambiguous clinical scenarios. The successful treatment of these challenging cases highlights the versatility of the technique.1, 2, 3

The retrograde approach using PTA access in IFAP repair offers several advantages, particularly when traditional access methods fail. This approach provides an alternative route for endovascular intervention, especially useful in patients with previous surgical/endovascular interventions and pre-existing CFA disease or tortuous anatomy.⁴ In our series, PTA access was preferred for cases where contralateral femoral or radial approach would be circuitous or high risk owing to iliac occlusive disease or significant groin scarring from prior interventions. Studies have demonstrated that retrograde access via PTA is technically feasible and safe—albeit primarily in the context of vascular disease intervention—with Dubosq et al⁴ reporting 100% technical success without intraoperative complications. Retrograde access can reduce procedure time by allowing a more linear route and providing short, direct access to the lesion. Hua et al⁵ found significantly shorter operation times using tibial retrograde access compared with popliteal access in peripheral intervention, benefiting overall procedural risks and patient outcomes. The approach has shown promising patency rates after peripheral intervention. Dubosq et al⁴ reported a 100% primary patency rate at 30 days, indicating effective and durable outcomes.

Although these reports have established the safety and feasibility of pedal access in peripheral interventions, its application in pseudoaneurysm treatment remains limited.^4,5 Our series expands this utility by demonstrating excellent outcomes without the need for surgical conversion or prolonged compression. Notably, access vessel integrity was preserved in all patients, and the use of small-caliber sheaths may have contributed to reduced complication risk.

However, pedal access is limited in patients with pre-existing peripheral vascular disease owing to compromised vascular integrity and increased risk of complications. Chronic anterior ankle ulcers or superficial femoral artery calcification, narrowing, and occlusion complicate pedal access, as seen in patients 5 and 6. The radial artery offers a viable alternative, particularly when femoral or pedal access is contraindicated. Despite challenges such as tortuosity and vasospasms, this approach offers reduced access-site complications and enhanced postprocedure mobility. Maximus et al⁶ found radial artery access to be safe for endovascular treatment of lower extremity peripheral artery disease, with comparable safety profiles to brachial and femoral access. Both patients 5 and 6 achieved successful CFA pseudoaneurysm resolution through our modified radial-access BATI technique.

The procedure's success stems from several key aspects. Distal peripheral access eliminates femoral pseudoaneurysm risk and reduces life-threatening hemorrhage, as described by Vowels et al.³ Real-time ultrasound guidance enables precise targeting, while balloon tamponade prevents thrombin washout and reduces arterial leakage risk. This technique enhances safety by preventing inadvertent vessel wall entry and minimizing systemic thrombin circulation, which can cause distal embolization.⁷ Balloon-assisted injection effectively reduces required thrombin by occluding the neck of the pseudoaneurysm, allowing a more controlled and localized injection. Krueger et al⁸ reported mean doses of 425.31 IU for unassisted injections in 240 patients and 520.33 IU for complex cases, while our series achieved resolution with a lower average of 276.17 IU. In our series, the balloon was inflated for 10 minutes without heparin. Thrombin (5,000 U) was diluted with 5 mL diluent, then 1 mL of this mixture was further diluted with 4 to 5 mL saline to create a 200 unit/mL solution. Typically, 1 to 2 mL sufficed. After injection, we allowed for clotting (which occurred in <10 minutes) before slowly deflating the balloon to prevent clot suction. Despite concerns about CFA damage from balloon expansion, 1:1 sizing was used in all cases, with nominal pressures. All patients achieved successful pseudoaneurysm exclusion without hemorrhage or perforation despite varying CFA calcification, matching the 100% success rate of Bruno et al⁷ with the contralateral femoral approach.

The technique demonstrated immediate technical success and sustained resolution without recurrence during follow-up. Menon et al¹ reported 100% positive outcomes in follow-up with complex femoral pseudoaneurysm exclusion with contralateral CFA access, and Schellhammer et al1, 9 showed sustained occlusion over 10.2 months. Postprocedure angiography, ultrasound, CTA, and clinic follow-up confirmed parent artery patency in our cases, corroborating results reported in the literature.

Safety and risk mitigation are central advantages of percutaneous BATI. Performed under local anesthesia with minimal sedation, this technique avoids surgical risks—general anesthesia, wound infection, prolonged recovery—making it advantageous for patients with high surgical risk.⁴ This safety profile is well documented across multiple studies.1, 2, 3^,9,10 Compared to UGCR and subcutaneous UGTI, it shows superior efficacy for complex anatomies. UGCR has variable success and high recurrence rates for wide-neck pseudoaneurysms, while standard UGTI requires higher thrombin volumes, increasing thrombosis risks. PTA access reduces complications, similar to the transradial benefits reported by Watanabe et al¹⁰ Given this favorable profile, we maintain a low threshold for intervention, particularly for wide-necked pseudoaneurysms >5 mm that fail initial compression repair.

However, UGTI remains the first-line approach for most pseudoaneurysms, including those with moderately wide necks, given its high success rate and low complication profile. Major complications such as thrombosis or embolization are exceedingly rare in experienced hands. BATI should not replace UGTI in routine cases but should rather serve as a complementary strategy in anatomically complex or high-risk scenarios. In such cases, BATI offers enhanced control and precision, particularly when paired with operator expertise in pedal access and the use of dual-imaging modalities.

While promising, technique limitations include small sample size and relatively short follow-up. The safety of pedal access is primarily supported by data from peripheral interventions, and its use in pseudoaneurysm treatment remains an extrapolated application. Larger prospective studies with extended follow-up are needed to evaluate the long-term outcomes and to determine optimal management strategies for different IFAP types.

Conclusions

Our case series demonstrates that percutaneous ultrasound-guided BATI safely and effectively treats complexIFAPs. The distal access approach provides a valuable alternative, offering technical feasibility, safety, efficiency, high patency, and minimally invasive options for challenging cases. While further studies are needed for long-term evaluation, this technique shows promise for managing this complication.

Visual Summary.

Timeline of Events

Patient	Time	Event
Patient 1	Day 0	Left subclavian stenting via right CFA with Angio-Seal closure
	Day 5	Presented with hypertensive emergency and pulsatile groin mass; CDUS showed pseudoaneurysm (5.50-mm neck)
	Same day	Failed UGCR; underwent BATI via right PTA with 300 IU thrombin and 7.0-mm balloon
	8-mo follow-up	No recurrence on imaging
Patient 2	Day 0	PCI via right CFA with Mynx closure
	Overnight	Developed expanding hematoma and pseudoaneurysm (6.00-mm neck); failed UGCR and FemoStop
	Same day	BATI via right PTA with 195 IU thrombin and 6.0-mm balloon
	9-mo follow-up	No recurrence
Patient 3	Day 0	Diagnostic angiography post-CABG; Angio-Seal used
	Day 5	Presented with pseudoaneurysm (5.50-mm neck); failed UGCR and FemoStop
	Same day	BATI via right PTA with 250 IU thrombin and 7.0-mm balloon
	6-mo follow-up	No recurrence
Patient 4	Day 0	Bilateral CFA access for iliac stenting with Mynx closure
	Next morning	Developed hemorrhagic shock; pseudoaneurysm (5.94-mm neck) confirmed on CDUS
	Same day	BATI via right PTA with 360 IU thrombin and 6.0-mm balloon
	72-h follow-up	No recurrence
Patient 5	Unspecified	Post-TAVR complication; pseudoaneurysm (6.29-mm neck) at left CFA
	Same day	BATI via right radial access with 260 IU thrombin and 7.0-mm balloon
	3-mo follow-up	No recurrence
Patient 6	Day 0	Revascularization via left CFA with Angio-Seal
	Day 1	Developed pseudoaneurysm (6.95-mm neck); confirmed on imaging
	Same day	BATI via right radial access with 292 IU thrombin and 7.0-mm balloon
	2-mo follow-up	No recurrence

Timeline of events for 6 patients who underwent modified BATI via distal access for wide-neck femoral pseudoaneurysms.

BATI = balloon-assisted thrombin injection; CABG = coronary artery bypass grafting; CFA = common femoral artery; PTA = posterior tibial artery; TAVR = transcatheter aortic valve replacement; UGCR = ultrasound-guided compression repair.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Appendix

Video 1

Angiogram of Right CFA Pseudoaneurysm of Patient 6

Angiography via right radial access of left CFA pseudoaneurysm before ultrasound-guided BATI of patient 6.

Video 2

Angiogram of Balloon Tamponade During Balloon-Assisted Thrombin Injection of Patient 6

Fluoroscopy showing ultrasound-guided BATI via PTA access. A 7.0-mm balloon provided tamponade during ultrasound-guided thrombin injection of patient 6.

Video 3

Angiography of Pseudoaneurysm Exclusion Post-BATI of Patient 6

Angiography of patient 6 showing resolution of wide-necked pseudoaneurysm with preserved flow to the native CFA after ultrasound-guided BATI via radial access. Results were sustained at the 2-month follow-up.