**12. Discussion**

*Aortic Aneurysm and Aortic Dissection*

lumbar vertebra L3-L4 (**Figure 4**).

normalized.

intravenous (initially) and oral antibiotics.

allograft was performed in both cases (**Figure 5**).

with gas within the aneurysmal sac, measuring 9 cm in diameter (**Figure 4**). Further preoperative MRI-imaging revealed spondylodiscitis at the level of the

The patient was taken to the operating room and underwent an aorto-aortic straight rifampicin-bonded Dacron bypass-graft. Subsequent aortic wall tissue and blood cultures were found to be both positive for *Staphylococcus aureus*. Intravenous antibiotics were continued throughout the admission period and for 3 months after. After evaluation of the vertebral osteomyelitis by the orthopedic and microbiologist teams, he was discharged from the hospital 14 days after surgery on long-term

Since 2011, we have performed in our center a novel hybrid repair in 2 cases of mycotic aortic aneurysms (MAAs), one of them a primary juxtarenal MAA, and the other one a suspected inflammatory infrarenal aortic aneurysm. This hybrid repair consisted in a two-stage procedure, performed within at least one-month difference, or once inflammatory markers and radiologic imaging studies had

The first stage of the procedure consisted in performing an open repair of the MAA, with interposition of a cryopreserved arterial allograft. This was done in 2 patients who presented with abdominal pain and a pulsatile mass on physical examination, with a CT angiogram that showed a contained ruptured aortic aneurysm in both cases. An aorto-aortic bypass graft using a cryopreserved arterial

*Intraoperative images showing the surgical preparation of the arterial aortic cryopreserved allografts (A and B).*

*Patient 3. CT scan revealing a juxtarenal MAA with gas within the aneurysmal sac (B), measuring 9 cm in diameter (A). Magnetic resonance imaging (MRI) showing vertebral osteomyelitis (spondylodiscitis) in a* 

*sagittal plane, with bone erosion (red arrow) at the level of vertebral bodies L3-L4 (C).*

**58**

**Figure 5.**

**Figure 4.**

Treatment of aortic infection is still one of the most challenging situations for a vascular surgeon to confront.

Open extra-anatomic bypass revascularization combined with extensive debridement of all infected aortic and peri-aortic tissues, with excision of the infected aorta and oversewing of the non-infected aortic stump has been considered the standard treatment for aortic infection [22, 26, 31].

Open surgical options include the use of antibiotic-soaked Dacron grafts, cryopreserved aortic allografts, and biological bovine pericardial materials. The use of the superficial femoral vein (SFV)and femoral or popliteal vein segments have also been used as an alternative to in situ reconstructions in aortic infections [26, 32]. Revascularizations using vein grafts have the advantage of a potential lower risk of infection/reinfection. SFV as an autologous material has shown excellent performance in terms of long-term infectious complications. The main disadvantage is that vein harvesting is time-consuming. Another possible disadvantage of using the SFV is its diameter discrepancy with the aorta, and the possible limitation of vein length. These vein reconstructions are also functional and durable on follow-up over time [47–49].

Some groups have presented lower rates of recurrent infection and lower morbidity and mortality rates associated with rifampicin-soaked Dacron grafts compared to those with untreated grafts [35, 45].

Cryopreserved arterial allografts have the advantage of a higher resistance to infection, with low rates of reinfection. Techniques in cryopreservation have improved in the last decade, possibly contributing to better outcomes of revascularization using these allografts [35, 41, 50].

MAAs of the ascending aorta and aortic arch, without a past medical history of previous cardiac or cardiovascular surgery, are very rare. Macedo et al. reported an incidence of 2.6% of MAAs of the ascending aorta after a review of their more than 25-year experience with aortic mycotic aneurysms [51]. Descriptions of mycotic ascending aortic aneurysms or pseudoaneurysms in the literature are very scarce. MAAs of the thoracoabdominal aorta are also less common than those of the infrarenal aorta. Previous series have presented an incidence of primary infection of the thoracic and thoracoabdominal aorta affecting 0.7–4.5% of aortic aneurysms altogether [35]. Mycotic saccular, fusiform, and pseudoaneurysms of the ascending and descending thoracic aorta have been described in the literature. Repair of these aneurysms may be performed with different techniques, including cryopreserved arterial homografts, prosthetic antibiotic-soaked grafts, visceral debranching and endovascular stent-graft repairs, bovine pericardium patch grafts, and Dacron grafts with biological tissue coverage [35, 45, 52].

The largest series of mycotic aortic aneurysms was presented by Heinola et al. in 2018. This international multicenter study included 187 patients. In their series, 51

patients (27%) were treated with open prosthetic repair, 56 (30%) with a biological material, and 80 were treated with EVAR (43%). Overall, open repairs were performed in 107 patients (57%) in this group, making this the largest series up to date on open aortic repair of MAAs [32]. In their analysis, blood and/or tissue culture were positive in 43 (77%) cases, 33 (59%) were positive for non-*Salmonella* infection, and 10 (18%) were positive for *Salmonella* species. The most common registered bacterium on cultures was *Staphylococcus aureus* (27%). It presented a thirty-day survival of 95% (n = 53) and 90-day survival of 91% (n = 51). The overall treatment-related mortality was 9% (n = 5) [32].

The second largest study to date of open surgical treatment of mycotic aortic aneurysms (MAAs) was published in 2014 by Lin et al., including a group of 77 patients. In this study group, the in-hospital mortality rate was 10% (8/77) for patients who underwent open repair and 25% (2/8) for patients who underwent EVAR [27].

The first report of endovascular aneurysm repair of a MAA was reported in 1998 by Semba et al. They reported no postoperative complications from persistent bacteraemia after a 24-month follow up, without postoperative mortality [53]. Since then, there have been various case reports and series of cases describing EVAR and TEVAR for the treatment of ruptured aortic aneurysms and MAAs and their outcomes [23, 30, 34, 38, 39, 53]. These series report favorable results for EVAR/TEVAR for MAAs, providing a less invasive procedure with low early mortality rates [23, 30, 33, 34, 39, 53].

Kan et al. performed a systematic review of outcome after EVAR for the treatment of mycotic aortic aneurysms in 2007. They presented a life-time analysis, which reported a 30-day survival rate of 89% +/− 4% and a 2-year survival rate of 82% +/−5.8%. They performed a multivariate logistic regression analysis, which showed that only ruptured aneurysms and fever were significant predictors of persistent infection in EVAR after MAAs [38].

The largest series to date on endovascular treatment of MAAs was reported in 2018 by Heinola et al. This multicenter-group reported 187 MAAs treated in 6 different European countries between 2006 and 2016 [32]. Another previous large series on endovascular treatment of MAAs was reported in 2012 by Sedivy et al. This series included 32 patients, treated during a 15-year period. In this series, 81% of patients survived the 30-day postoperative period. A total of 50% survived after 1-year follow-up and 40% survived after a 3-year follow-up [50]. **Table 3** includes the most important series regarding MAAs (**Table 3**) [22–32, 35, 38–41, 54].

Although some of these modern series present promising results, with lower 30-day mortality for endovascular treatments compared to open surgery, the risk of persistent infection and late complications might be higher. Some concerns are present in modern literature regarding endovascular repair, as there are still no long-term follow-up of these series and there is still an ongoing controversy and debate regarding placing a stent-graft in a tissue (aorta) that is still infected.

For some complex thoracoabdominal aortic aneurysms (TAAAs), therapeutic options may be scarce. In those cases of symptomatic mycotic TAAAs, there may not be enough time to create fenestrated/branched custom-made endovascular stentgrafts. In order to avoid the high morbidity and mortality rates associated with total open surgical repair of these mycotic TAAAs, some groups have advocated for the performance of a hybrid aortic repair.

This hybrid repair of type I, II, and III TAAAs consists in performing a visceral artery debranching with retrograde revascularization, followed by the implantations of a thoracoabdominal endovascular stent-graft [42, 55, 56].

Contrary to what happens in the infrarenal abdominal aorta, extra-anatomic bypasses are very exceptionally used to repair primary MAAs of the thoracic and

**61**

**Table 3.**

*Mycotic Aortic Aneurysms*

*DOI: http://dx.doi.org/10.5772/intechopen.86328*

thoracoabdominal aorta, or graft infections on those sites. Patients with mycotic aneurysms of the ascending aorta or arch may present with different signs and symptoms, including persistent fever, fatigue, chest or back pain, dyspnea, pleural

*Open, open surgical repair; EVAR, endovascular aneurysm repair; TEVAR, thoracic endovascular aneurysm repair.*

MAAs have also reported following heart transplantation and different cardiac surgical procedures. Bacterial, viral, fungal, and protozoal infections have been described after cardiac transplantation, understanding that these patients under immunosuppressive medication are at risk of mycotic aneurysm formation [58]. In cases of ascending, arch, or descending thoracic mycotic aneurysms associated with severe mediastinitis, surgical techniques for aortic repair include cryopreserved arterial homografts, repair with deep or superficial femoral veins, coverage with the use of the greater omentum, creation of pedicled muscular flaps for arterial cover-

**Series Year Number patients Technique Mortality (30-day)** Moneta 1998 17 Open 23% Soravia-Dunand 1999 10 Open 57% Oderich 2001 43 Open 21% Müller 2001 33 Open 36% Fillmore 2003 10 Open 40% Kyriakides 2004 15 Open 26% Dubois 2010 44 Open 18.2% Kan 2010 41 Open (n = 21) 4.8%

Yu 2011 53 Open 23% Weis-Müller 2011 36 Open 33% Uchida 2012 23 Open 5% Sedivy 2012 32 EVAR-TEVAR 18.8% Huang 2014 43 Open (n = 29) 20%

Lin 2014 109 Open (n = 77) 10%

Sörelius 2014 123 EVAR-TEVAR 9% Touma 2014 16 Open-Allograft 28% Sörelius 2016 132 Open (n = 62) 26%

Luo 2017 40 EVAR-TEVAR 10% Corvera 2018 17 Open-Allograft 6%

Heinola 2018 187 Open (n = 51)

*Largest modern series of mycotic aortic aneurysms (MAAs).*

EVAR (n = 20) 5%

EVAR (n = 11) 9%

EVAR (n = 8) 25%

EVAR (n = 70) 14%

5%

EVAR (n = 80) Allograft (n = 56)

We described in this chapter 2 cases of a novel hybrid repair of MAAs, including a staged hybrid procedure, with a first stage including resection of the infected

effusion, and hypovolemic shock in cases of mycotic aortic rupture [57].

age, tissue debridement, and sternal re-closure [45, 57, 58].


*Mycotic Aortic Aneurysms DOI: http://dx.doi.org/10.5772/intechopen.86328*

*Aortic Aneurysm and Aortic Dissection*

EVAR [27].

treatment-related mortality was 9% (n = 5) [32].

mortality rates [23, 30, 33, 34, 39, 53].

performance of a hybrid aortic repair.

persistent infection in EVAR after MAAs [38].

patients (27%) were treated with open prosthetic repair, 56 (30%) with a biological material, and 80 were treated with EVAR (43%). Overall, open repairs were performed in 107 patients (57%) in this group, making this the largest series up to date on open aortic repair of MAAs [32]. In their analysis, blood and/or tissue culture were positive in 43 (77%) cases, 33 (59%) were positive for non-*Salmonella* infection, and 10 (18%) were positive for *Salmonella* species. The most common registered bacterium on cultures was *Staphylococcus aureus* (27%). It presented a thirty-day survival of 95% (n = 53) and 90-day survival of 91% (n = 51). The overall

The second largest study to date of open surgical treatment of mycotic aortic aneurysms (MAAs) was published in 2014 by Lin et al., including a group of 77 patients. In this study group, the in-hospital mortality rate was 10% (8/77) for patients who underwent open repair and 25% (2/8) for patients who underwent

The first report of endovascular aneurysm repair of a MAA was reported in 1998 by Semba et al. They reported no postoperative complications from persistent bacteraemia after a 24-month follow up, without postoperative mortality [53]. Since then, there have been various case reports and series of cases describing EVAR and TEVAR for the treatment of ruptured aortic aneurysms and MAAs and their outcomes [23, 30, 34, 38, 39, 53]. These series report favorable results for EVAR/TEVAR for MAAs, providing a less invasive procedure with low early

Kan et al. performed a systematic review of outcome after EVAR for the treatment of mycotic aortic aneurysms in 2007. They presented a life-time analysis, which reported a 30-day survival rate of 89% +/− 4% and a 2-year survival rate of 82% +/−5.8%. They performed a multivariate logistic regression analysis, which showed that only ruptured aneurysms and fever were significant predictors of

The largest series to date on endovascular treatment of MAAs was reported in 2018 by Heinola et al. This multicenter-group reported 187 MAAs treated in 6 different European countries between 2006 and 2016 [32]. Another previous large series on endovascular treatment of MAAs was reported in 2012 by Sedivy et al. This series included 32 patients, treated during a 15-year period. In this series, 81% of patients survived the 30-day postoperative period. A total of 50% survived after 1-year follow-up and 40% survived after a 3-year follow-up [50]. **Table 3** includes the most important series regarding MAAs (**Table 3**) [22–32, 35, 38–41, 54]. Although some of these modern series present promising results, with lower 30-day mortality for endovascular treatments compared to open surgery, the risk of persistent infection and late complications might be higher. Some concerns are present in modern literature regarding endovascular repair, as there are still no long-term follow-up of these series and there is still an ongoing controversy and debate regarding placing a stent-graft in a tissue (aorta) that is still infected.

For some complex thoracoabdominal aortic aneurysms (TAAAs), therapeutic options may be scarce. In those cases of symptomatic mycotic TAAAs, there may not be enough time to create fenestrated/branched custom-made endovascular stentgrafts. In order to avoid the high morbidity and mortality rates associated with total open surgical repair of these mycotic TAAAs, some groups have advocated for the

This hybrid repair of type I, II, and III TAAAs consists in performing a visceral artery debranching with retrograde revascularization, followed by the implanta-

Contrary to what happens in the infrarenal abdominal aorta, extra-anatomic bypasses are very exceptionally used to repair primary MAAs of the thoracic and

tions of a thoracoabdominal endovascular stent-graft [42, 55, 56].

**60**

*Open, open surgical repair; EVAR, endovascular aneurysm repair; TEVAR, thoracic endovascular aneurysm repair.*

#### **Table 3.**

*Largest modern series of mycotic aortic aneurysms (MAAs).*

thoracoabdominal aorta, or graft infections on those sites. Patients with mycotic aneurysms of the ascending aorta or arch may present with different signs and symptoms, including persistent fever, fatigue, chest or back pain, dyspnea, pleural effusion, and hypovolemic shock in cases of mycotic aortic rupture [57].

MAAs have also reported following heart transplantation and different cardiac surgical procedures. Bacterial, viral, fungal, and protozoal infections have been described after cardiac transplantation, understanding that these patients under immunosuppressive medication are at risk of mycotic aneurysm formation [58]. In cases of ascending, arch, or descending thoracic mycotic aneurysms associated with severe mediastinitis, surgical techniques for aortic repair include cryopreserved arterial homografts, repair with deep or superficial femoral veins, coverage with the use of the greater omentum, creation of pedicled muscular flaps for arterial coverage, tissue debridement, and sternal re-closure [45, 57, 58].

We described in this chapter 2 cases of a novel hybrid repair of MAAs, including a staged hybrid procedure, with a first stage including resection of the infected aneurysm and repair with an aortic cryopreserved arterial allograft, followed by a second procedure (once inflammatory markers have decreased and radiologic features have normalized) consisting of an aortic stent-graft. We believe that this option might minimize the risk of cryopreserved allograft rupture that has been previously described in the literature in cases of MAAs. Although there are no reports describing this technique, we consider that this might be a feasible alternative to prevent the risk of aortic rupture.

Long-term surveillance, including physical examination, laboratory assessment of inflammatory markers, and imaging studies (incorporating CT angiogram and FDG-PET or PET-CT) are critical for evaluation of possible complications and prompt decision in case of reinfections.
