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Percutaneous Repair of Aortic Pseudoaneurysms: A Case Series
Abstract: Background. Aortic pseudoaneurysms (APSAs) are an uncommon but serious complication of aortic surgery with potentially fatal complications if left untreated. Operative repair is associated with significant morbidity and mortality. Percutaneous APSA repair may reduce the risk of these complications and represents an alternative option for patients. We report our experience with percutaneous intervention for the treatment of APSAs. Methods and Results. We retrospectively reviewed all patients at our institution who underwent percutaneous APSA repair with Amplatzer septal occluders and vascular plugs between January 2004 and September 2014. Ten patients are included in this study, representing our first cases of percutaneous APSA repair. Follow-up was performed with serial computed tomographic angiography. The primary outcome was the success rate of device deployment. Secondary outcomes included success rate of complete APSA exclusion, postprocedural symptoms, and periprocedural and postprocedural complications. Mean clinical follow-up time was 12 months (range, 5-30 months) and mean imaging follow-up time was 29 months (range, 14-52 months). Device deployment was successful in all patients, although 2 patients required reintervention due to device malposition and the discovery of additional defects on postprocedure CT angiography. There were no periprocedural or postprocedure complications. Long-term follow-up imaging was available for 7 patients and revealed complete APSA exclusion in 4 patients. One out of the remaining 3 patients ultimately required operative intervention. Conclusions. Percutaneous APSA repair can be performed safely with a good procedural success, albeit with variable long-term results. This procedure may be considered as an alternative to surgical repair in select patients.
J INVASIVE CARDIOL 2016;28(1):E6-E10
Key words: aortic pseudoaneurysm, percutaneous repair, septal occluder, vascular plug, intraluminal echocardiography
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The etiologies of aortic pseudoaneurysm (APSA) are varied and include trauma, mycotic infections, and iatrogenesis. The most common cause of APSA is from complications of aortic surgery, with a postsurgical incidence estimated at 1%-4%.1,2 If left untreated, these pseudoaneurysms can rupture, fistulize, and compress or erode surrounding structures.3 The most commonly used option for postsurgical APSA occurrence is probably reoperation, which requires resternotomy and cardiopulmonary bypass with or without the use of deep hypothermic circulatory arrest. However, reoperation is associated with a high mortality rate of 30% at 1 month.4-6 As a result, it is attractive to consider a percutaneous option, with the intention of avoiding repeat operation. Multiple techniques for percutaneous treatment of APSA have been attempted, including thrombin plug injection, coil embolization, endovascular stent-graft placement, and implantation of occluder devices. The goal of each of these techniques remains the same — to induce thrombosis within the pseudoaneurysm, effectively excluding it from the aortic lumen. There is a paucity of published data with regard to procedural success and outcomes, and there is no equipment specifically designed to address this type of medical condition. We report our experience with the first 10 patients who underwent percutaneous repair of aortic pseudoaneurysms with Amplatzer septal occluders (ASOs) and Amplatzer vascular plugs (AVPs; St. Jude Medical) at our institution.
Methods
A total of 10 patients underwent percutaneous treatment for APSA between January 2004 and September 2014 at our institution. Prior to consideration of each procedure, patients underwent evaluation by a cardiothoracic surgeon. Decisions to intervene percutaneously were made via team approach and were based upon a perceived high operative mortality and/or morbidity as well as the feasibility of a percutaneous approach.
Technical challenges include adequate imaging, identification of appropriate closure device, and identification of suitably sized catheters to deliver those devices. Feasibility was determined by the size of the pseudoaneurysm neck and the availability of a suitable plugging device. Amplatzer septal occluders were used when possible, as their disks form a secure hold on surrounding structures and can conform to the intraluminal wall of the aorta, which are theoretically advantageous features with regard to the risk of device embolization. However, it was not always possible to deliver an Amplatzer septal occluder to the APSA due to the lack of long enough and/or large enough sheaths to deliver the appropriately sized devices. Amplatzer vascular occluders (AVP II and AVP IV) were used with greater frequency given their less stringent delivery requirements. While septal occluders require sheaths ranging between 7-12 Fr, vascular plugs can be delivered through 4-7 Fr sheaths or 5-9 Fr guide catheters.
Procedures were done under either conscious sedation or general anesthesia, with general anesthesia selected if transesophageal echocardiography (TEE) guidance was to be used. The typical approach involved at least one arterial access site; however, many of the procedures involved either dual-arterial access and some required venous access to allow for intracardiac echo imaging. Initially, procedures were guided by TEE to ensure proper device sizing and placement. By the third procedure, either intracardiac echocardiography (ICE) or intraluminal echocardiography (ILE) was preferentially used. ILE involves placing the endovascular echo probe retrograde into the ascending aorta with or without a guiding sheath. In most cases, ICE/ILE provided optimal imaging due to frequent shadowing of TEE imaging in the ascending aorta.
Arterial access was typically obtained via the femoral artery; however, 3 procedures were successfully performed via radial artery approach. One procedure was attempted using the ulnar artery, but was converted to femoral access after unsuccessful cannulation of the APSA. Arterial sheath size was most commonly 8 Fr but ranged between 5 Fr and 10 Fr, with smaller sizes used for radial and ulnar artery access. There was a wide variety of guide catheters that were successful at cannulating the APSA for device deployment. These included the JR4 guide, No-Torque right guide, FR4 guide, AL1 guide, right coronary artery bypass graft guide, multipurpose guide, and Ikari right guide catheters. A Jacky diagnostic catheter was used to deliver AVP IV devices. Guiding sheaths were used when they were long enough to reach the defects.
Initial device sizing relied upon preprocedure computed tomographic angiography (CTA), although final device sizing was made from intraprocedural imaging with echocardiography, as well as assessment via trial-and-error placement of a device. The device was sized according to the APSA neck diameter and typically oversized by 1-2 mm, such that a 7 mm or 8 mm vascular plug might be used on a 6 mm neck diameter. Proper device deployment was confirmed intraprocedurally via aortography, TTE, ICE/ILE, or a combination of these imaging modalities.
Intravenous heparin was bolused prior to device deployment in all cases, with a goal activated clotting time (ACT) of 250 seconds or greater. All patients were started or continued on 81 mg of aspirin for a minimum of 6 months post procedure. Patients requiring warfarin for mechanical valves were continued post procedure. All patients received antibiotic prophylaxis during the procedure.
The primary outcome was the success rate of device deployment. We defined this as the ability to properly place a device within the neck of the APSA regardless of successful APSA exclusion. Secondary outcomes included success of APSA exclusion, need for reintervention, postprocedural symptoms, and periprocedural and postprocedural complications. Success of APSA exclusion was evaluated via serial CTA imaging and defined as the complete absence of contrast within the APSA following device deployment. Periprocedural complications were evaluated, including device malposition, defined as device deployment in a vascular space other than the APSA neck, and hemodynamic or electrical instability requiring procedure cessation or lengthening of procedure time. Evaluated postprocedural complications included vascular complications and device migration. Outcomes were obtained via a detailed chart and serial CTA review of each patient. Internal Review Board (IRB) approval was attained, granting permission to report on procedural outcomes in the absence of informed consent due to the retrospective design of the study.
Results
Patients. Subjects ranged in age from 22-80 years. All of our patients experienced APSAs as a result of a prior cardiac surgery. Previous surgeries included aortic root replacement (n = 2), ascending aortic graft placement (n = 4), and descending thoracic aortic repair (n = 2), with additional APSAs occurring at the cannula insertion site for cardiopulmonary bypass (n = 2) (Figure 1A). In 4 patients, the initial aortic insult was an aortic dissection. APSAs varied in location from as proximal as the aortic root to as distal as the descending thoracic aorta. Three patients had an APSA in the ascending aorta adjacent to the right coronary artery ostium.
All patients were initially diagnosed using CTA. Five patients were diagnosed incidentally on routine postoperative surveillance (Figure 2A), 3 patients presented with symptoms of chest or epigastric pain, 1 patient experienced dyspnea and was found to have a concomitant aortic paravalvular leak that was treated at the time of APSA repair, and 1 patient presented with non-specific symptoms of fatigue. APSA size, as assessed by CTA, ranged between 6 mm (anterior-posterior) x 4 mm (transverse) x 12 mm (longitudinal) and 45 mm x 67 mm x 79 mm. In 1 patient, an APSA originating at the non-coronary sinus of Valsalva was found to be compressing the ascending aorta, although this patient remained asymptomatic.
Procedural outcomes. The procedure was well tolerated by all 10 patients. No hemodynamically or electrically significant events occurred. AVPs ranging in size from 6-16 mm were deployed in 6 patients. Four of these patients required two AVPs each due to multiple APSA connections with the aortic lumen, and 1 patient received four AVP IV devices — two each during two separate interventions. Two patients received ASOs (6 mm and 10 mm) and 1 patient received an 18 mm Amplatzer patent foramen ovale occluder (this patient was presented in a previous case report).18
Proper device deployment was confirmed in 8 out of 10 patients intraprocedurally via TEE, ICE/ILE, or aortography (Figures 1B and 2B). In 1 patient, both ICE and aortography were unable to confirm proper device placement. This patient, early in our experience, had aortography that failed to reveal the defect, highlighting the challenges of imaging for this condition. This patient underwent a postprocedure magnetic resonance image that showed improper device placement within the false lumen of a dissected ascending aneurysm. Within 1 week, the patient was taken back for a repeat attempt at percutaneous repair, which was successful under ICE guidance. In another patient, two AVP IV devices were placed in two separate pseudoaneurysms, with an apparently successful result by angiography and TEE. However, CTA revealed two additional defects, which were subsequently closed with two more AVP IV devices using ICE guidance.
Intraprocedural confirmation of APSA exclusion was obtained by TEE or ICE/ILE, along with aortography. Eight of 10 patients were found to have complete APSA exclusion intraprocedurally via these imaging techniques, with the other 2 patients having subsequent successful procedures using ICE/ILE guidance. A postprocedural CTA was obtained within a 2-week period in all patients and revealed residual APSA leaks in 3 patients.
Follow-up. Follow-up CTA imaging (in addition to immediate postprocedure imaging) was obtained in 7 patients with a mean CTA follow-up time of 29 months (range, 14-52 months). Three patients were <1 year out and follow-up CT images have not yet been obtained. Four patients experienced complete APSA exclusion at 17, 23, 29, and 52 months. Two patients experienced residual leaks with only mild expansion of the APSA at 21 and 45 months. Neither patient has undergone repeat intervention to date. One patient was found to have a recurrent, expanding APSA 9 months post procedure and was reintervened upon percutaneously. Two months after the second intervention, surveillance imaging revealed a persistent APSA. The patient ultimately underwent surgical repair of the APSA with concomitant aortic valve replacement, suffered an intraoperative stroke, and died in the postoperative period.
Of the 6 patients who showed complete APSA exclusion immediately post procedure via CTA, 1 developed a recurrent APSA leak with mild expansion seen on 19-month follow-up imaging, and 3 patients have yet to undergo follow-up CTA imaging. Of the 4 patients who showed a residual APSA leak immediately post procedure, 1 patient was found to have device malposition within the false lumen of a dissected aorta (described above). A repeat intervention resulted in proper device positioning, although postprocedural imaging continued to show a mild persistent APSA leak. Three-month follow-up CTA imaging of this patient ultimately revealed complete APSA exclusion, which was maintained for the duration of the follow-up period. One patient had additional defects successfully closed (described above). The other 2 patients experienced ongoing leaks with APSA expansion, one of which required operative intervention. The second patient has undergone no further interventions, and notably, remains chronically anticoagulated with coumadin given a history of a mechanical mitral valve replacement.
All patients were followed clinically for a mean of 12 months (range, 5-30 months). All patients remained asymptomatic following the procedure. The 4 patients who presented with symptoms experienced complete resolution of these symptoms within the follow-up period. None of the patients experienced vascular complications or device migration within the follow-up period.
Discussion
The mechanism of a successful percutaneous APSA repair is by cutting off blood flow to the pseudoaneurysm in order to induce thrombosis within it and prevent further pressurization of its weak walls. Multiple techniques have been described, including thrombin injection, coil embolization, and endovascular stent deployment, which have all been shown to effectively treat APSAs in case reports.7-10 Nevertheless, these techniques each have their drawbacks. Lin et al reported neurologic complications post thrombin injection due to thrombus propagation from the ascending aortic pseudoaneurysm to the cerebral circulation.11 Coil embolization has shown success;8 however, multiple coils may be needed to treat large APSAs. Aslam et al report an attempt at APSA closure with coils; however, incomplete filling of the pseudoaneurysm with coils ultimately led to vascular plug deployment.9 Endovascular stenting of the aorta can be technically challenging as no specific endoprosthesis has been developed or approved for ascending aortic repair, and occlusion or disruption of surrounding structures can be problematic (arch vessels, aortic valve, coronary arteries, bypass grafts).10,12
The use of septal occluders and vascular plugs in APSA exclusion was first described in a 2005 case report by Bashir et al.13 Since this time, there have been only a handful of published case reports and small case series describing APSA closure with Amplatzer atrial and ventricular septal occluders.14-19 The largest case series reported on 6 patients, of which 2 required open repairs due to inappropriate device delivery and inability to properly size a device.16 No follow-up was reported. Longer follow-up has been published in isolated case reports, the longest of which showed a good outcome at 2 years.14-19
We present the largest case series to date for percutaneous APSA repair, which includes an average clinical follow-up time of 12 months and imaging follow-up time of 29 months. Our experience shows that device deployment can be achieved with a high success rate. Of our 10 patients who underwent percutaneous closure of APSAs with ASOs and/or vascular plugs, our primary outcome of successful device deployment was achieved in 8 patients. In the 2 remaining patients, a second procedure was required and ultimately resulted in successful device delivery. These cases points out the challenges of intraprocedural imaging as neither aortography nor TEE adequately revealed the defect during the initial procedures.
All 10 of our patients tolerated a total of thirteen procedures without hemodynamic or electrical instability. Neither vascular complications nor device embolization were observed in the follow-up period. Device malposition was experienced in 1 of 10 patients due to misinterpretation of the imaging; however, this did not adversely affect the patient or prevent a second attempt at closure, which was ultimately successful under ILE guidance. We believe the use of ICE/ILE greatly aided in proper device sizing and provided superior imaging for device deployment compared with TEE in our cohort (Figure 3).
We found that APSA exclusion can be achieved via a percutaneous approach using septal occluders and vascular plugs, however, with varying long-term success. Of the 7 patients in whom follow-up CTA images have been obtained, only 4 patients experienced complete APSA exclusion throughout the entire follow-up period. One patient ultimately required surgical intervention for an expanding APSA and died in the postoperative period following a stroke, highlighting the risks of surgery and the difficult decisions in the treatment of this patient population. It is unclear whether the use of the percutaneous treatment staved off this complication or contributed to it by creating thrombus within the pseudoaneurysm, which might have contributed to the postoperative stroke. The other 2 patients have yet to undergo additional therapies and are followed with routine imaging.
Recurrence of the APSA was seen in 2 patients, at 2 and 19 months post procedure, despite initial postprocedure evidence of APSA exclusion by CTA. Additionally, APSA exclusion was ultimately seen in 1 patient at 3 months post procedure, despite a persistent APSA seen on the postprocedural CTA. These findings suggest that routine surveillance imaging may be necessary for several months to years post procedure regardless of initial outcome.
Conclusion
The treatment of APSAs presents many challenges. Many patients are at high risk for perioperative complications. Imaging, device selection, and identifying suitable catheters for device delivery present technical challenges for a condition that is not frequently seen. Nevertheless, in select patients, percutaneous closure of APSAs with septal occluder devices and vascular plugs may be considered an alternative to high-risk surgical intervention. Optimal management of these complex lesions should include a multidisciplinary approach between surgeons and interventionalists. Technical challenges needing to be considered in the performance of these procedures include adequate imaging and adequate sizing of delivery sheaths and/or guiding catheters.
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From the 1University of Washington Medical Center, Department of Cardiology; 2Harborview Medical Center, Department of Cardiology; and 3University of Washington Medical Center, Division of Cardiothoracic Surgery.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Gill is a consultant and instructor for Phillips. Dr Goldberg reports proctor and consultant fees from St. Jude Medical. The remaining authors report no conflicts of interest regarding the content herein.
Manuscript submitted March 15, 2015, provisional acceptance given April 13, 2015, final version accepted May 18, 2015.
Address for correspondence: Steven L. Goldberg, MD, Professor of Cardiology, Director of the Cardiac Catheterization Laboratory, Department of Cardiology, 1959 NE Pacific Street, Box 356422, Suite AA522, Seattle, WA 98195-6422. Email: stevgolduw@gmail.com
