Asian Cardiovasc Thorac Ann 2004;12:254-256
© 2004 Asia Publishing EXchange Ltd
Ruptured Chronic Traumatic Mycotic Pseudoaneurysm of the Ascending Aorta
Sashidhar V Yeluri, MBBS,
Apurva B Vaidya, MS,
Hima J Patel, MD,
Sumit R Kapadia, MS,
Siddharth Karanth, MBBS
Department of Cardiothoracic and Vascular Surgery, Sri Sayaji General Hospital and Medical College, Baroda, Gujarat, India
For reprint information contact: Sashidhar V Yeluri, MBBS Tel: 91 98 2404 3388 Fax: 91 26 5278 0019 Email: y.sashidhar{at}mailcity.com 1 Madhuram Duplex, Near Chanakyapuri Char Rasta, New Sama Road, Baroda 390008, Gujarat, India.
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ABSTRACT
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We report a rare case of posttraumatic chronic mycotic pseudoaneurysm of the ascending aorta presenting with acute rupture. The uniqueness of the case lies in its unusual etiology, presentation, and management with direct repair of the aorta without using cardiopulmonary bypass.
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INTRODUCTION
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Mycotic aortic aneurysms include both pseudoaneurysms caused by arterial infection and true aneurysms that have become secondarily infected. An aneurysm that persists for over 3 months after the original traumatic event is considered chronic. Mycotic aneurysms are rare and found predominantly in the abdominal aorta, while 15% of the cases occur in the descending thoracic aorta and another 15% in the ascending thoracic aorta. In a 50-year study spanning from the pre- to the post-antibiotic era, mycotic aneurysms constituted 2.6% of 338 aneurysms in 23,000 necropsies.1 We present a case of a ruptured chronic mycotic pseudoaneurysm of the ascending aorta of unusual etiology, which was successfully repaired without the use of cardiopulmonary bypass (CPB).
A 35-year-old tribal male residing in a remote backward tribal belt unknowingly sustained an accidental bullet splinter injury to his sternum. The wound presented as a chronic pus-discharging sinus that did not respond to locally available treatments. Almost a year later, he noticed a sudden spurt of blood from the wound and was rushed to a nearby hospital. Bleeding was controlled by packing. Chest radiography showed a metallic foreign body impacted in the sternum with surrounding osteomyelitis and mediastinal widening (Figure 1A
).
The patient was promptly referred to our center, where he underwent emergency sternotomy following resuscitation. An important constraint was the unavailability of CPB. The sinus was explored, and the foreign body wedged in the bone was removed. Clots apparently dislodged, resulting in profuse bleeding. A 16F Foley’s catheter was introduced through the sinus and the balloon inflated to produce a tamponade effect (Figure 1B
). Hypotension incidentally helped control the bleeding, as the aorta became soft. Sternotomy and pericardiotomy were performed to provide access to the aorta.
The rent in the aorta, about 1 x 1 cm in size, was found in an anterior and extrapericardial location, just proximal to the origin of the brachiocephalic trunk. It had thick and fibrous edges. A side-biting clamp was applied to the aorta before the Foley’s catheter was removed. Direct repair of the lesion was performed with 3/0 polypropylene multiple interrupted sutures taking large bites of the edges. The entire repair took 15 minutes with the partial clamp in place (Figure 1C). The osteomyelitic portion in the sternum was resected widely, and the sternotomy was closed in the usual manner with an additional drain left in the infected portion.
Total blood loss was about 3 L, and about 8 units of blood were transfused. Hypotension of about 40 to 50 mm Hg systolic was encountered for about 30 minutes. Ventilatory and inotropic support was provided for 24 hours. The postoperative course was uneventful. Cultures of specimens from the osteomyelitic bone revealed staphylococci.
The patient was given 8 weeks’ supply of antibiotics. He was well at 3 and 12 months after the operation with normal echocardiograms, and he had started with his normal routine activities.
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DISCUSSION
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Rupture of the ascending aorta is almost always lethal. We found only about 10 cases of chronic traumatic pseudoaneurysm of the ascending aorta documented in the literature, most of them related to vehicular accidents.2,3 The absence of the mycotic component in these cases and its presence in our patient makes this case unique. As recently as 1997, Chen and colleagues4 in their exhaustive review of the literature found only 43 cases of mycotic aneurysm of the ascending aorta, none of them related to chronic trauma, unlike the present case. Our own review of the literature did not reveal a similar case, making this case possibly the first of its kind.
Mycotic pseudoaneurysm of the aorta may result from bacterial colonization in a variety of ways. It may arise from bacteremia with organisms lodging in a diseased and roughened atherosclerotic focus, or from bacteria lodging in a vasa vasorum of a normal aorta during bacteremia in patients with pneumonia, cholangitis, or endocarditis. It may also result from sepsis due to an external source, such as trauma, intravenous injection, or surgery, and from direct extension from lymphadenitis or osteomyelitis. In the present case, the impacted foreign body caused osteomyelitis, which in turn led to mycotic pseudoaneurysm of the ascending aorta.
Computed tomography and aortography are gold standards for the diagnosis of mycotic aneurysm or pseudoaneurysm. Features on the tomographic scan that may indicate a mycotic pseudoaneurysm include a very thin aneurysmal wall, a multilobular shape, and distortion of the hematoma cavity by adjacent bony and vascular structures.5 In unruptured cases, transesophageal echocardiography is another diagnostic option. Management includes extensive resuscitation in cases of rupture and repair performed under CPB. Adequate debridement and eradication of the infection together with prosthesis implantation or, if feasible as in the present case, direct arterial repair is carried out. Dacron and polytetrafluoroethylene are the most commonly used prosthetic materials.
A review of the literature for traumatic aneurysm of the aorta shows evidence that CPB is not necessary if the operation is performed promptly.6 Although cardiac dilatation and strain, ischemia of visceral vessels, and paraplegia may occur if CPB is not used, Crawford and Rubio6 showed that surgery could be performed safely with simple clamping of the aorta, pharmacologic support, and lowering of left ventricular pressure with nitroprusside in traumatic aneurysm of the descending aorta. They believed that the incidence of paraplegia is no greater compared to patients managed with CPB or a shunt and that operative time and blood loss are usually less with their direct approach. In traumatic transection of the ascending aorta, full heparinization and CPB are usually required.7
The most commonly isolated organisms in mycotic aneurysm are Staphylococci (30% of cases) and Salmonellae (10%). The pathogenic microorganism in our case was Staphylococcus. Ideally, in mycotic aneurysm, appropriate antibiotic therapy should be started before surgery, initially with broad-spectrum antibiotics until culture and sensitivity studies indicate the specific antibiotic therapy needed. Some authors recommend 6 to 8 weeks of therapy as opposed to others’ suggestion of lifelong therapy. Increasing antibiotic resistance and problems associated with lifelong antibiotic therapy should influence the treatment regimen. We believe treatment should be individualized.
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ACKNOWLEDGMENTS
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The authors would like to thank Miss Kruti Bhatt and Dr. Guneesh Dadayal for their excellent overall help, and for helping with the illustrations.
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REFERENCES
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- Parkhurst GF, Decker JP. Bacterial aortitis and mycotic aneurysms of aorta. Am J Pathol
1955;31:821–35.
- Albuquerque FC, Krasna MJ, McLaughlin JS. Chronic, traumatic pseudoaneurysm of the ascending aorta. Ann Thorac Surg
1992;54:980–2.[Abstract]
- Finkelmeier BA, Mentzer RM, Kaiser DL, Tegtmeyer CJ, Nolan SP. Chronic traumatic thoracic aneurysm: influence of operative treatment on natural history. An analysis of reported cases, 1950–1980. J Thorac Cardiovasc Surg
1983;84:257–66.
- Chen YF, Lin PY, Yen HW, Lin CC. Double mycotic aneurysms of the ascending aorta. Ann Thorac Surg
1997;63:529–31.[Abstract/Free Full Text]
- Reed DH. Case report: mycotic pseudoaneurysm of the descending thoracic aorta associated with vertebral osteomyelitis. Clin Radiol
1990;41:427–9.[Medline]
- Crawford ES, Rubio PA. Reappraisal of adjuncts to avoid ischemia in the treatment of aneurysms of descending thoracic aorta. J Thorac Cardiovasc Surg
1973;66:693–704.[Medline]
- Castagna J, Nelson RJ. Blunt injuries to branches of the aortic arch. J Thorac Cardiovasc Surg
1975;69:521–32.[Abstract]
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ABSTRACT
INTRODUCTION
