Payman J. Danielpour, Chief Resident, Department of Surgery; Pragatheeshwar Thirunavukarasu, Resident, Department of Surgery; Manuel Sivina, Chief, Department of Vascular and General Surgery, Mount Sinai Medical Center, Miami Beach, FL
Payman J. Danielpour, MD
Department of Surgery
Pragatheeshwar Thirunavukarasu, MBBS
Department of Surgery
Manuel Sivina, MD
Chief Department of Vascular and
Mount Sinai Medical Center
Miami Beach, FL
Pseudoaneurysms, also known as false aneurysms, occur when blood from an artery leaks into surrounding tissue, forming a hematoma with a liquid core that communicates with the main lumen of the primary vessel via a narrow neck. The main concern is rupture, and prompt diagnosis and treatment are imperative to avoid morbidity and mortality. The authors report an unusual case of a pseudoaneurysm of the abdominal aorta in an elderly woman and discuss the etiology, risk factors, incidence, diagnosis, and management of these rare lesions.
Pseudoaneurysms of the abdominal aorta are rare, especially those found to be mycotic. Abdominal pseudo-aneurysms following trauma have been reported fairly often.1,2 We report a rare case of an infected pseudoaneurysm of the abdominal aorta at the level of the renal arteries that resulted after cardiac catheterization and discuss the management of this case. We also review the literature regarding pseudoaneurysms.
An 81-year-old white woman with a medical history signi%uFB01cant for angina pectoris, myocardial infarction, hypertension, type 1 diabetes mellitus, chronic anemia, congestive heart failure, and cardiac arrhythmia was admitted to a neighboring hospital after a syncopal episode. Her complete syncope workup was negative. The patient was referred to our institution for cardiac catheterization and evaluation for placement of an automatic implantable cardioverter de%uFB01brillator.
Upon admission to our institution, the patient was afebrile and her vital signs were stable, but her blood pressure was slightly elevated at 157/65 mm Hg. The initial physical examination was notable for an audible grade 2/6 mitral regurgitation murmur and a grade 1-2/6 soft diastolic blow murmur, suggesting aortic regurgitation and diffuse rhonchi. The patient was evaluated by the interventional cardiology team and taken for cardiac catheterization, which was performed through the right femoral artery using a No. 6 French sheath and a 6F XB 3.5 guiding catheter. A percutaneous transluminal coronary angioplasty was performed due to 90% stenosis of the second diagonal artery of the left anterior descending artery. According to the cardiology report, the patient tolerated the procedure well and without complications.
Figure—CT scan showing the pseudoaneurysm involving the renal arteries.
On day 4 following her catheterization, the patient developed fever and abdominal pain. The fever workup was remarkable for blood cultures that were positive for vancomycin-sensitive . The infectious disease team was consulted, and a computed tomography (CT) scan of the abdomen and pelvis showed a %uFB02uid collection surrounding the anterior aspect of the aorta at the level of renal arteries (Figure). This collection appeared to represent an aortic leak with subsequent development of a possibly infected pseudoaneurysm. Ultrasonography of the aorta revealed a hypoechoic structure surrounding the midabdominal aorta, most likely representing a pseudoaneurysm with organizing hematoma.
Upon this %uFB01nding, a vascular surgery consultation was obtained, during which the patient had stable vital signs and was awake, alert, and afebrile. Her physical examination was unremarkable except for a tender abdomen with a palpable pulsatile abdominal mass. The patient was taken to the operating room, where a retroperitoneal approach allowed proximal control of the aorta above the renal arteries and distal control below. The pseudoaneurysm was resected along with fractured arteriosclerotic plaque. The specimen and cultures from the area that grossly appeared infected were sent to pathology. The entire lateral wall of the aorta involving the right and the left renal arteries was debrided due to suspicion that it could be infected. An 18-mm Dacron tube graft was placed with an end-to-end anastomosis. After graft placement, the left renal artery appeared to be compromised; thus, a left end-to-side iliorenal artery bypass with a 6-mm Gore-Tex? graft was performed.
Postoperatively, the patient's renal function was preserved and she had good urine output and normal creatinine and blood urea nitrogen levels. Renal ultrasonography on postoperative day 7 revealed no abnormalities. The patient's recovery was uneventful, and she was discharged from the hospital on postoperative day 8. Because the postoperative cultures from the site were positive for vancomycin-sensitive , the patient was to continue intravenous vancomycin for 6 weeks. She was instructed to follow up at 2-month intervals and continue oral antibiotics for 1 year.
Pseudoaneurysms, known to physicians since ancient times, were a common complication of bloodletting, a practice that was popular for more than 2,000 years.3 These lesions received considerable attention after the %uFB01rst successful direct arterial repair performed by Lambert in 1759 for a brachial artery pseudoaneurysm after phlebotomy.4 Anastomotic pseudoaneurysms often complicated early prosthetic graft operations due to the degeneration of silk sutures,5-7 and traumatic pseudoaneurysms have become common recently, possibly due to an increase in civilian violence. A considerable fraction of pseudoaneurysms can be attributed to interventional diagnostic and therapeutic procedures that involve arterial punctures.8
Pseudoaneurysms of the abdominal aorta account for about 1% of all aortic aneurysms, and only 5% of all pseudo-aneurysms are located below the diaphragm.9,10 Pseudoaneurysms of the abdominal aorta are rare and most commonly result after trauma or aortic aneurysm repairs.
Pseudoaneurysms occur due to a discontinuity in the wall of the vessel, leading to an extravasation of blood that becomes walled off by connective tissues. These lesions can be considered contained aneurysmal ruptures. The most commonly cited cause is trauma; the %uFB01rst such case was reported by Mankins in 1920 and involved a gunshot wound.1 In 1991, Potts and Alguire reported a case of an abdominal pseudoaneurysm after blunt trauma and reviewed 22 similar cases in the literature, all of which involved male patients ranging in age from 7 to 75 years.2
Aspergillus, Mycobacteria, Salmonella, Brucella,
Infection of the aorta is another major cause of pseudoaneurysms. An infection in the aorta leads to aortitis, which weakens the wall of the aorta, allowing it to be penetrated by advancing in%uFB02ammation and resulting in leakage of blood to the para-aortic region. This blood may later coagulate to form a pseudoaneurysm. The usual etiologic agents of mycotic aneurysms are and .11 Miller and colleagues identi%uFB01ed pseudoaneurysms in 7% of 29 cases of infected aneurysms of the descending thoracic and abdominal aorta that were treated at the Mayo Clinic over a 23-year period.11 Isolated cases of pseudoaneurysms of the abdominal aorta associated with hydatid disease, and have been reported, demonstrating the wide variety of organisms that can cause mycotic pseudoaneurysms.12-17
Pseudoaneurysms, such as those of the femoral artery, are common following invasive interventional radiological procedures, but those involving the abdominal aorta have been described only rarely. In a review of the literature assessing over 180,000 femoral arterial access procedures, iatrogenic pseudoaneurysms were found to have an incidence rate of 0.2%.8
Several risk factors for the development of iatrogenic pseudoaneurysms have been identified, including female gender, extremes of age, increased body weight, and the presence of systemic hypertension or congestive heart failure.18-27 Our patient had most of these patient risk factors. Procedural risk factors include large catheter size, therapeutic versus diagnostic procedure, use of multiple catheters and punctures, prolonged procedure time, limited surgical experience, and concomitant use of thrombolytic agents.19,25,28-33 Some interesting and rare causes of pseudoaneurysms include aortic penetration with a bird's nest vena cava %uFB01lter; procedures such as laparoscopic cholecystectomy, umbilical artery cauterization in infants, and celiac plexus block for chronic pancreatitis pain; and acupuncture.34-41 Vasculitides (such as periarteritis nodosa, giant cell arteritis, and Behcet's disease42) traditionally have been associated with aneurysm formation and can, in later stages, lead to the formation of pseudoaneurysms through perforations resulting from transmural necrosis, which occurs secondary to medial destruction and occlusion of the vasa vasorum.
The usual presentation of a pseudo-aneurysm of the abdominal aorta includes low back pain and a pulsatile mass in the abdomen. The clinical triad of lower back pain, fever, and a painful pulsatile abdominal mass are considered highly suggestive of an abdominal mycotic aneurysm, even in the absence of positive blood cultures.43 Such a presentation also may occur with abdominal aortic pseudoaneurysms, and detailed investigation by abdominal ultrasonography and CT scanning are warranted in patients with abdominal pain and fever in whom a source of infection cannot be identi%uFB01ed.
Diagnosis is aided by duplex ultrasonography, CT scanning, and angiography. Arteriography was once the mainstay for diagnosing aneurysms, but abdominal ultrasonography now is considered a more reasonable option, because it is noninvasive and inexpensive. Coughlin and Paushter documented the sensitivity and speci%uFB01city of using pulse wave Doppler imaging to diagnose pseudoaneurysms as 94% and 97%, respectively.44 CT scanning is used frequently, because it helps physicians identify the relationship between the pathological dilatation of the vessel and nearby structures. CT scanning also has been reported to be useful in evaluating infected abdominal aneurysms.45 In a study by Lee and associates, magnetic resonance imaging proved useful in diagnosing abdominal aortic aneurysms and was more reliable than ultrasonography in determining the relationship between the aneurysm and the renal and iliac arteries.46 Despite these advantages, ultrasonography is recommended as the initial screening procedure for suspected abdominal aortic aneurysms because of its low cost and ease of use. Positive blood cultures and elevated leukocyte counts help establish the diagnosis of an infected aneurysm or pseudo-aneurysm, but blood cultures occasionally may be negative.43
The main and most worrisome complication is rupture, which may lead to rapid exsanguination and death, as reported in 80% of cases.9 The potential for serious complications like chronic pain, vascular occlusion, nerve compression syndromes, infected thrombus, sepsis, renovascular hypertension, and hemothorax necessitate early diagnosis and elective surgical repair of abdominal pseudoaneurysms.47-51
In 1888, Mata reported the %uFB01rst successful repair of a pseudoaneurysm.52 He performed an endoaneurysmorrhaphy to repair a traumatic left brachial artery aneurysm caused by a gunshot wound. In 1907, Lexer described the repair of pseudoaneurysms using vein grafts.53 In 1976, Bole and colleagues reviewed 32 cases of traumatic pseudoaneurysms, of which 21 were treated surgically.54 Resection with end-to-end anastomosis was done in eight patients, with lateral repair in seven of the patients and graft repair in one. Hypothermia with circulatory arrest and an external Dacron shunt were used to prevent visceral ischemia during high aortic occlusion. Bole and colleagues reported no mortalities or signi%uFB01cant postoperative complications.
Traumatic pseudoaneurysms in the para visceral abdominal aorta have been treated successfully using open surgical repair, endovascular repair with covered aortic stent grafts and angiographic coil embolization, and intra-arterial injection of thrombin into the pseudoaneurysm sac.55 Successful endovascular repairs of pseudoaneurysms have been reported frequently over the last decade. Parodi described a series of 57 patients with abdominal aortic aneurysm and other arterial lesions that were treated with endovascular stent grafts.56 Of these patients, 50 had abdominal aortic aneurysms or iliac aneurysms, 5 had traumatic arteriovenous %uFB01stulas, and 2 had infected femoral false aneurysms. A Dacron graft or an autogenous vein graft sutured to a balloon-expandable stent were the devices used for repair. The stent grafts were placed through remote arteriotomies, advanced under fluoroscopic guidance to their predetermined sites, and secured into position. Of the 50 endovascular stent graft procedures used to treat abdominal aortic or iliac aneurysms, 40 were considered successful, even though secondary treatment was required in 6 cases. Two patients who needed further intervention required open operations, and the remainder needed secondary endovascular procedures. The two pseudoaneurysms and all %uFB01ve arteriovenous %uFB01stulas were treated successfully using endovascular stent grafts.
Endovascular stent procedures have been used successfully to treat infected hepatic-celiac pseudoaneurysms and external iliac artery pseudoaneurysms infected with methicillin-resistant .57,58 In 2000, Maruyama and associates successfully treated 2 of 6 aortic pseudoaneurysms (3 thoracoabdominal, 2 thoracic, and 1 abdominal) using endovascular stent procedures.59 One patient died in the perioperative period due to massive hemoptysis before stent grafting, two died of persistent infection, and one had a persistent perigraft leak and died due to rupture. The authors concluded that stent graft placements for aortic pseudoaneurysms might serve as a temporizing method before surgical repair in high-risk cases and be a therapeutic alternative for those without infection or perigraft leakage.
In a study of 13 infected aortic aneurysms and pseudoaneurysms (5 thoracic, 4 paravisceral, and 4 infrarenal) in 10 consecutive patients treated with aortic debridement and in situ repair, there were no reports of hospital deaths, limb loss, renal failure, or intestinal ischemia, but two late deaths did occur from sepsis and pneumonia.60 The authors concluded that surgical treatment for aortic aneurysms and pseudoaneurysms with in situ reconstruction is associated with a favorable outcome and good long-term results, with endovascular repair only required under certain circumstances. In a Mayo Clinic study, placement of cryopreserved allografts for aortic reconstructions due to primary graft infections, mycotic aneurysms, and aortic graft-enteric erosions was reviewed extensively.61 These grafts were associated with high mortality rates, but most deaths did not result from allograft failure. Preliminary data from that registry also failed to justify the preferential use of cryopreserved allografts for primary graft infections, mycotic aneurysms, and aortic graft-enteric erosions.
Our patient's case is unique in several ways. First, she presented in the post-catheterization period, which has not been reported previously in the literature. We hypothesize that during catheterization of the aorta, the catheter or guidewire lifted or perforated an atherosclerotic plaque. Dye was injected during the procedure and most likely leaked, along with blood from the puncture or dissection, and accumulated. An infection developed, resulting in a pseudoaneurysm. Second, the patient's pseudoaneurysm was grossly infected with an organism sensitive only to vancomycin. Third, the pseudoaneurysm was situated at the level of the renal arteries, thereby increasing the risk of renal complications, morbidity, and mortality.
Considering the dif%uFB01culties, complications, and uncertainties (of adequate debridement) that might arise with endovascular repair of an infected pseudo-aneurysm at the level of the renal arteries, it seemed more appropriate to intervene using an open surgical technique. The only endovascular repair option was to use a graft with an opening for the renal arteries; however, that approach carried a high risk for infection and required considerable expertise in endovascular surgery. The decision to approach this patient via an open surgical approach was twofold. First, and most importantly, open debridement was required due to infection. Second, direct visualization of the renal arteries would decrease the likelihood of renal complications. A retroperitoneal approach was preferred in our case due to the expertise of the surgeon.
Pseudoaneurysms of the abdominal aorta are rare and usually result from trauma. Another common cause of these lesions is infection of the abdominal aorta, which can result after procedures such as cardiac catheterization. Early diagnosis and surgical repair of infected abdominal aortic pseudoaneurysms are essential in alleviating distressing symptoms and preventing other potentially serious complications, especially death. A high index of suspicion, prompt clinical evaluation, early diagnosis by appropriate investigations such as blood cultures, duplex ultrasonography, and CT scanning, and timely surgical repair are the keys to successful management.