eComment. Antimicrobial vascular grafts in cardiac surgery.

We read with great interest the paper by Yano et al. regarding the successful surgical management of an 81-year old female patient with a septic aortic pseudoaneurysm secondary to Escherichia coli, which presented as cardiac tamponade [1]. In our opinion, a few remarks with respect to the surgical strategy and types of vascular graft ought to be addressed. The term “mycotic aneurysm” was first used in 1885 by Sir William Osler because of the beaded and multilobulated appearance of the aneurysm formation occurring in malignant endocarditis [2]. However, the use of septic aortic pseudoaneurysm (SAP) in this case report is more accurate. Septic aortic pseudoaneurysm is used to describe aortic pseudoaneurysm caused by bacterial invasion of the vessel wall, with or without bacteremia. SAP is a potentially life-threatening aortic lesion. It is uncommon, but not rare, and an increasing incidence has been reported in recent years [2]. Treatment is usually bimodal with intensive antibiotic therapy as well as surgical repair; furthermore, surgical treatment of SAP remains challenging. A literature review of surgical treatment of SAP in the abdominal or thoracic portion of the aorta can be confusing [2]. Whether a patient should undergo extra-anatomic bypass grafting or in situ reconstruction with prosthetic graft or allograft is not well-established and remains a matter of ongoing debate. However, the most performed strategy in this setting is the in situ reconstruction with prosthetic graft. It consists of an aggressive and extensive debridement of infected tissue (aortic wall and surrounding tissue) and irrigation of the operative field with antiseptic agent. Aortic continuity is then reconstructed with an in situ graft and the prosthetic graft is protected with a great omentum pedicle. An extra-anatomic reconstruction is technically challenging but is not impossible, as stated by the authors. A review by Oz et al. [3] showed that the aforementioned technique applied in 24 patients with thoracic SAP is feasible; however it is more challenging because it requires multiple operations. Luo et al. [3] described a different technique to repair small SAP located on the distal aortic arch. Under cardiopulmonary bypass with deep hypothermia and circulatory arrest, they excise the SAP and repair the defect with patch aortoplasty. In the setting of small SAP, patch aortoplasty can be an alternative method; this was the case in the patient presented by Yano et al. [1] Antibiotic-bonded grafts (e.g., rifampicin-bonded Dacron grafts) and silver-coated Dacron grafts are increasingly been used in vascular surgery to prevent graft infection or to treat abdominal aortic infection with encouraging outcomes [4-5]. The availability of the silver-coated Dacron grafts in different types and sizes, its ease of use and its durability remain important advantages. To the best of our knowledge, these grafts have never been used to replace the thoracic aorta. We think that antimicrobial grafts can represent an alternative to aortic allografts and to standard Dacron grafts with omental wrapping and should be considered in the armamentarium of every cardiac surgeon. Conflict of interest: none declared