Endovascular repair of a ruptured, mycotic popliteal aneurysm

Abstract

In 1985 Osler used the expression; ‘mycotic aneurysm’ in relation to aneurysms of septic aetiology. In his reported case the infective embolic source was septic endocarditis.1 Currently the term mycotic aneurysm is used in a broad sense; it covers all aneurysms of infective aetiology, both bacterial and fungal in nature. According to recent data the most frequent infective organisms are Staphylococcus and Salmonella.2,3 The femoral artery and the abdominal aorta are the most common locations of septic aneurysms, the popliteal artery has rarely been implicated.3,4 Primary vascular surgical repair of mycotic aneurysms is often impossible or contraindicated in an infected operating field on a seriously ill patient. Patients may end up with ligation of a major artery, for example, superficial femoral or popliteal artery as an emergency procedure.3 Extra-anatomical vascular reconstruction or endovascular repair remain the other treatment alternatives. Elective endovascular repair of popliteal aneurysms has gained momentum in recent years. Tielliu et al. presented 76% 5-year patency rate after elective endograft insertion in a series of 73 patients.5 Endovascular treatment of a ruptured, non-infected, popliteal aneurysm was reported by Ihlberg.6 Our case report demonstrates successful endovascular management of a ruptured mycotic popliteal aneurysm. A previously well 80-year-old man presented in the Emergency Department with few days history of increasing back pain, abdominal discomfort, fever and malaise. An MRI examination of the thoracolumbar spine was suggestive of osteomyelitis of the 10th thoracic vertebra as the most likely primary focus of a blood-born infection. Blood cultures confirmed staphylococcus aureus sepsis (Methicillin sensitive) which was treated with intravenous Flucloxacillin. A subsequent echocardiography demonstrated thickened aortic and mitral valve leaflets, raising the suspicion of endocarditis. A week after hospital admission sudden onset of left-leg swelling was noted and subsequently the patient developed a large painful pulsatile mass in the popliteal fossa extending up to the medial and posterior aspects of the thigh. A CT scan examination revealed the aneurysmal popliteal artery and large periarterial haematoma formation. X-ray contrast appeared in the haematoma indicating the rupture and contrast communication with the pulsating haematoma (Fig. 1). The haematoma extended proximally on the posterior aspect of the thigh (Fig. 2). Ruptured mycotic popliteal aneurysm (CT angiography). Periarterial haematoma extending up to mid thigh level (computed tomography). The patient was transferred to the operating theatre where under local anaesthesia and sedation percutaneous, antegrade femoral puncture was made and an 8mm × 10 cm Viabahn endoprosthesis (Viabahn, WL Gore, Flagstaff, Az, USA) was deployed in the popliteal artery. The post-procedural angiography and the subsequent CT angiography showed excellent flow through the endograft. The endograft successfully sealed the popliteal artery rupture, there was no further evidence of contrast extravasation (Fig. 3). Patent endograft 1 week and 6 months after graft placement. No evidence of endoleak (CT angiography). The postoperative period was uneventful. Early ambulation was commenced. He stayed on antibiotics for another 6 weeks. All the inflammatory markers normalized. Two months after the procedure the thigh haematoma decreased significantly in size. At 6 months the duplex scan examination and CT angiography confirmed the patent endograft without evidence of endoleak (Fig. 3). Endovascular surgery under local anesthesia was our preferred option in a severly ill patient under emergency circumstances. The popliteal artery was anatomically suitable for the procedure and a fast satisfactory outcome was achieved. By providing long-term, adequate antibiotic cover the risk of endograft sepsis was minimized and the infection was eradicated. Recently published papers analyse the value of endovascular treatment in the management of mycotic aortic and iliac aneurysms.7,8 There have been no data to date on endovascular management of ruptured mycotic popliteal aneurysms. The recommendations and calls for caution by certain authors7,8 can be extended to the management of popliteal aneurysms. Before deciding the best intervention one has to weigh the risk of implanting a synthetic graft material in the infected popliteal artery against the burden of major surgery that also carries the risk of ischaemic and further septic complications. We were encouraged by the reported satisfactory longer term patency rates following elective endovascular repair of popliteal aneurysms5 and the emergency situation also shifted our decision making towards endovascular treatment. Our case report indicates that endovascular treatment may be a useful alternative to conventional surgery in this special group of patients.