Management of Aortic Pseudoaneurysms: Evolving Concepts and Controversies

Background  Techniques to repair aortic pseudoaneurysms have been rapidly evolving. We present our results following open and endovascular repair of aortic pseudoaneurysms from 2009 to 2013. Methods  A total of nine patients underwent pseudoaneurysm repair from April 2009 to February 2013. Of them, five underwent open repair and four underwent endovascular repair. The median age was 58 years (range, 40–72 years) and two (22%) were females. Preoperative, operative, and postoperative data are presented along with operative modality. Results  Two patients died during the period of study. Patient 1 died from massive hemorrhage at the site of prior stenting. Patient 7 died from postoperative cardiac arrest and respiratory failure. A single patient required hemorrhage-related reexploration. None of the patients experienced stroke or acute renal failure following repair. Median hospital and intensive care unit length of stays were 7.1 (range, 1–20) and 2.0 (range, 1–5), respectively. Conclusions  Pseudoaneurysm repair can be effectively achieved through open or percutaneous repair but only after careful consideration of anatomical constraints, as well as patient comorbidities.


Introduction
False aneurysms of the aorta, known as pseudoaneurysms, are hematomas formed outside the aortic wall, resulting from transmural disruption with the leak contained by surrounding mediastinal tissues. Previous cardiac surgery is the most frequent cause. 1 Typically pseudoaneurysms are a rare complication of aortic repair; however, in some studies, the incidence of pseudoaneurysm formation has been documented to manifest in as many as 7.7% of patients following aortic procedures. 2 Mechanisms implicated include infection, trauma, poor anastomotic technique, and intrinsic aortic wall disease. 1 Surgical treatments vary according to the features and locations of the pseudoaneurysm. Surgical challenges are frequent, especially in the presence of infection, prior cardiac surgery, and proximity of the pseudoaneurysm with the posterior sternal table making reentry particularly challenging. Less invasive options with coil embolization and pseudoaneurysm exclusion have also been reported. [3][4][5] Few studies have addressed the treatment of this complication. Herein, we describe our experience with endovascular and open surgical repair techniques for patients with pseudoaneurysms of the thoracic aorta.

Materials and Methods
From April 2009 to February 2013, a total of nine patients underwent repair of pseudoaneurysms of the ascending and thoracic aorta (►Table 1). Preoperative, operative, and postoperative data were obtained by review of medical records. Results Two patients died during the period of study. Patient 1 died from massive hemorrhage at the site of prior stenting. Patient 7 died from postoperative cardiac arrest and respiratory failure. A single patient required hemorrhage-related reexploration. None of the patients experienced stroke or acute renal failure following repair. Median hospital and intensive care unit length of stays were 7.1 (range, 1-20) and 2.0 (range, 1-5), respectively. Conclusions Pseudoaneurysm repair can be effectively achieved through open or percutaneous repair but only after careful consideration of anatomical constraints, as well as patient comorbidities.

Endovascular Repair
Endovascular repair was performed in four patients. Two patients had pseudoaneurysms of the descending thoracic aorta after repair of coarctation of the aorta and underwent repair with endovascular graft excluder of the pseudoaneurysms. One patient underwent aortic arch debranching and transaortic deployment of an endograft to exclude an arch pseudoaneurysm at a simultaneous setting. One patient with history of previous coronary bypass surgery developed a pseudoaneurysm at the aortic root vent site and underwent successful coil embolization and pseudoaneurysm exclusion.

Preoperative Characteristics
A total of 22% of patients were females, median age was 58 years (range, 40-72 years). Clinical presentation varied according to the location of pseudoaneurysm. Most common manifestations included chest pain (n ¼ 1), sepsis (n ¼ 3), and heart failure (n ¼ 2). Descending aortic pseudoaneurysms were asymptomatic and were identified as incidental findings on computed tomography. The location of the pseudoaneurysm was involving the proximal suture line in one patient and the distal suture line in four patients with aortic root or ascending aortic pseudoaneurysms. Infection was present in four patients and two patients had a history of endocarditis. Positive blood cultures were present in two patients.
Operative Characteristics ►Table 1 demonstrates the operative findings of patients as well as the interval period between the initial operation and development of the pseudoaneurysm. Patients 1 to 5 were all approached through the traditional open surgical method, while patients 6 to 9 underwent device deployment under fluoroscopic guidance. Most of the patients (7 of 9) had a pseudoaneurysm of the ascending aorta and only two patients had pseudoaneurysms of the descending aorta after previous coarctation repair.

Postoperative Characteristics
Two patients died during the period of the study. Patient 1 died from massive hemorrhage at the site of prior stenting. Patient 7 died from postoperative cardiac arrest and respiratory failure. A single patient required hemorrhage-related reexploration. No patients experienced stroke or acute renal failure following repair. Median hospital and intensive care unit length of stay were 7.1 (range, 1-20) and 2.0 (range, 1-5), respectively.

Indications for Repair
Most patients present with symptoms of chest pain, heart failure or symptoms related to sepsis. In our series, the main indications to intervene were symptoms and risk of impending rupture. 1 Size of the pseudoaneurysm was not used as a criterion for surgical intervention in our study. Although an incidental finding of pseudoaneurysm of descending aorta as a result of previous coarctation repair may occur, most patients were symptomatic. Common causes of pseudoaneurysms include leak at the anastomotic or cannulation sites, especially in patients with previous dissection repairs. Most patients are young but have had previous cardiovascular surgery; many have endocarditis. Most of our patients required ascending aorta and/or aortic root replacement.

Technical Challenges of Repair
Repair of pseudoaneurysms of the aorta is often complicated and associated with significant morbidity and mortality, especially when the pseudoaneurysm is in close proximity to the underside of the sternum. Open repair of these lesions may still be approached through a median sternotomy; however, some hypothesize that those more closely related to the sternum may be better candidates for a right anterior thoracotomy or a minimally invasive "J" incision. 1 However, measures were often taken to ensure safety. Cardiopulmonary bypass, for example, may be initiated before sternal entry in patients with a pseudoaneurysm lying in close approximation to the sternum. The pseudoaneurysm for patient 3 in our cohort was punctured upon initial entry into the chest requiring immediate initiation of cardiopulmonary bypass. The remaining three patients that had pseudoaneurysms abutting the sternum all underwent cardiopulmonary bypass via the femoral vessels prior to sternal reentry.

Percutaneous Repair: Pitfalls and Limitations
In the high risk setting, a minimally invasive approach using endovascular grafts or atrial septal occlusion devices can ameliorate some risks associated with open procedures, while providing adequate exclusion of the pseudoaneurysm sac. However, percutaneous devices are not without limitation. One requirement for occlusion device placement is a narrow neck between the pseudoaneurysm and the aorta to maintain adequate device seal upon deployment. Also, coil embolization can be useful to help achieving stasis within the pseudoaneurysm sac prior to device deployment; however, too many coils can push the device out of the sac, as was the case for patient 5.
The situation necessitated an open approach with pseudoaneurysm resection less than 1 year following the prior repair (►Fig. 1). In contrast, patient 6 underwent coil embolization of the pseudoaneurysm sac (►Fig. 1) prior to occluder placement and has since been asymptomatic.
Endovascular grafts have also been used for high-risk patients with device deployment over the orifice of the lesion. 5 Patients 7 to 9 underwent successful endovascular repair of pseudoaneurysms that would have either required a significantly more complicated open surgical route than the traditional approach or were better candidates for the endovascular approach due to the location of the lesion. For example, patients 8 and 9 both exhibited lesions in the descending aorta where adequate covering of the pseudoaneurysm was fairly easier to achieve without impinging upon other vessels. The pseudoaneurysm in patient 7 resided in close approximation to the manubrium. In this case, endograft deployment allowed for exclusion of the pseudoaneurysm without a median sternotomy. Often however, complete coverage of the lesion along with adequate proximal and distal sealing zones may be difficult to achieve when the pseudoaneurysm arises near the origin of the head vessels. Endovascular approach is often more feasible in patients with pseudoaneurysms of the descending aorta, as compared with those of the ascending aorta given the presence of adequate proximal and distal landing zone.

Conclusions
Our review demonstrates the challenges of repairing pseudoaneurysms and the variety of treatment modalities effective in repairing these lesions. We conclude that pseudoaneurysm repair can be effectively achieved through open or percutaneous repair but only after careful consideration of anatomical constraints, as well as patient comorbidities.

Funding
None.