Thoracic aortic endovascular repair for mycotic aneurysms and fistulas

Analysis of antibiotic strategies to prevent vascular graft or endograft infection after surgical treatment for infective native aortic aneurysms: a systematic review

INTRODUCTION

Some patients with an infective native aortic aneurysm (INAA) develop an aortic vascular graft or endograft infection (VGEI) even after successful open surgical repair or endovascular intervention. The aim of the systematic review and meta-analysis performed herein was to compare the clinical outcomes of different surgical and antibiotic treatment strategies.

METHODS

We systematically searched PubMed, MEDLINE, EMBASE and Web of Science. The keywords used for the search were "mycotic aortic aneurysm", "infected aortic aneurysm", "infective native aortic aneurysm", "antibiotics", "surgery", and "endovascular". The search was limited to articles written in English and to studies involving humans. Articles published before 2000 were excluded. Case reports and review articles were excluded.

RESULTS

Of the 524 studies retrieved from our search of the databases, 47 articles were included in this study. Among the 47 articles (1546 patients, 72.8% of whom were male) retrieved, five articles were excluded from the subgroup analysis because the data concerning open surgical repair and endovascular intervention could not be separated. The remaining 42 articles included a total of 1179 patients who underwent open surgical repair (622 patients) or endovascular intervention (557 patients) for INAA. There was a statistically significant difference (p = 0.001) in the pooled in-hospital mortality rate between the open surgical repair group (13.2%, 82/622) and the endovascular intervention group (7.2%, 40/557). However, there was a statistically significant difference (p < 0.001) in the aortic VGEI rate between the open surgical repair group (5.4%). 29/540) and endovascular intervention (13.3%, 69/517) group. For patients who underwent open surgical repair, a lower rate of aortic vascular graft infection was associated with long-term antibiotic use (p = 0.005). For patients who underwent endovascular intervention, there was a trend of association (p = 0.071) between the lower rate of aortic endograft infection and lifelong antibiotic use.

CONCLUSION

Infective native aortic aneurysms are life-threatening. The pooled in-hospital mortality rate of the open surgical repair group was significantly higher than that of the endovascular intervention group, whereas the rate of the aortic VGEI in the open surgical repair group was significantly lower than that in the endovascular intervention group. Regardless of whether open surgical repair or endovascular intervention is performed, better long-term outcomes can be achieved with aggressive antibiotic treatment, which is especially important for patients who undergo endovascular intervention.

Thoracoabdominal aortic aneurysmectomy in the high-risk patient

OBJECTIVE

The study objective was to provide a review of outcomes and management strategies for high-risk scenarios in the open repair of thoracoabdominal aortic aneurysms.

METHODS

Series examining the open repair of thoracoabdominal aortic aneurysms were reviewed to identify well-described high-risk scenarios and summarize expected outcomes and management strategies in the current era.

RESULTS

The efforts of many have led to improved outcomes for patients undergoing the inherently challenging open repair of thoracoabdominal aortic pathologies. Several well-described high-risk scenarios include those related to preoperative comorbid conditions (preoperative pulmonary dysfunction, low ejection fraction, and renal dysfunction), anatomically high-risk cases (extent II repairs), and those with acute presentations (rupture, mycotic aneurysms, acute complicated type B aortic dissection). Several operative and perioperative techniques have been developed to mitigate the risk in these formidable cases.

CONCLUSIONS

Challenges remain for several high-risk scenarios in thoracoabdominal aortic aneurysm repair. Judicious patient selection, meticulous surgical, and critical care strategies have greatly decreased the risk for many high-risk patients.

Early and late outcomes of surgical repair of mycotic aortic aneurysms: A 30-year experience

OBJECTIVE

Mycotic aortic aneurysm and its associated complications are often catastrophic. In this study, we examined the early and late outcomes of surgical repair of mycotic aortic aneurysm at our center over the last 3 decades.

METHODS

We retrospectively reviewed our prospectively maintained aortic surgery database with supplemental adjudication of medical records. Aortic infection was confirmed through clinical, radiological, intraoperative, pathological, and treatment evidence.

RESULTS

Seventy-five patients (median age, 68 years; interquartile range, 62-74) who underwent surgical repair of a mycotic aortic aneurysm between 1992 and 2021 were included. Almost all patients (n = 72; 96%) presented with symptoms, including 26 patients (35%) with rupture, and many underwent urgent or emergency repair (n = 64; 85%). Sixty-one patients underwent open repair, and 14 patients underwent hybrid or endovascular repair. Infection-specific adjunct techniques included rifampin-soaked grafts (n = 16), omental pedicle flaps (n = 21), and antibiotic irrigation catheters (n = 8). There were 15 early deaths (20%), including 10 of the 26 patients (38%) who presented with rupture; however, persistent stroke, paraplegia or paraparesis, and renal failure necessitating dialysis were uncommon (each <5%). Almost all early survivors (52/60; 87%) were discharged with long-term antibiotic therapy. Estimated survival at 2, 6, and 10 years was 55.7% ± 5.8%, 39.0% ± 5.7%, and 26.9% ± 5.5%, respectively.

CONCLUSIONS

A substantial proportion of patients with mycotic aortic aneurysm present with rupture and generally require urgent or emergency repair. Operative mortality and complications are common, especially for patients who present with rupture, and late survival is poor.

Mycotic Thoracic Aortic Aneurysm: Epidemiology, Pathophysiology, Diagnosis, and Management

Mycotic thoracic aortic aneurysm (MTAA) is an aneurysm of the aorta caused by infection of the vessel tissue through microbial inoculation of the diseased aortic endothelium. It is most commonly caused by bacteria. Rarely, it can be caused by fungi. However, viral aortic aneurysm has never been reported. Depending on the area and time period investigated, the infections organism discovered may vary significantly. Little is known about the natural history of MTAA due to its rarity. It is not known if they follow the same pattern as other TAAs. However, it is unclear whether MTAA follows a similar clinical course. The combination of clinical presentation, laboratory results, and radiographic results are used to make the diagnosis of MTAA. Treatment of MTAA is complex since patients frequently present at a late stage, frequently with fulminant sepsis, as well as concomitant complications such as aneurysm rupture. While medical treatment, including antibiotics, is recommended, surgery is still the mainstay of management. Surgery to treat MTAA is complicated and carries a high risk of morbidity and mortality and includes both open repairs and endovascular ones. In this review, we explore the etiology, pathogenesis, clinical presentations, diagnostic modalities as well as treatment management available for MTAA.

Imaging features of mycotic aortic aneurysms

Infectious aortitis (IA) is a rare and life-threatening cardiovascular disease. Early diagnosis and timely intervention are crucial for reducing mortality associated with mycotic aortic aneurysms (MAAs); however, early diagnosis is challenging due to the nonspecific symptoms. Some cases are diagnosed at an advanced stage or after developing complications, such as rupture or aortic fistula. Current state-of-the-art imaging modalities-including computed tomography (CT), magnetic resonance imaging (MRI), and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT-can detect infected aneurysms in clinically suspicious cases. MAA features on imaging include lobulated pseudoaneurysm, indistinct irregular arterial wall, perianeurysmal gas, perianeurysmal edema, perianeurysmal soft tissue mass, aneurysmal thrombosis, and high metabolic activity with increased uptake of FDG. Enlarged lymph nodes are often found adjacent to the aneurysm, while iliopsoas abscess (IPA), spondylitis, and aortic fistulas are commonly associated complications. After surgery or endovascular repair, radiological features-including ectopic gas, peri-graft fluid, thickening of adjacent bowel, pseudoaneurysm formed at the graft anastomosis, and increased uptake of FDG-may indicate an infection of aortic graft. This article provides an overview of the clinical and imaging features of MAAs. Thus, familiarity with the imaging appearances of MAAs may assist radiologists in the diagnosis and facilitation of timely treatment.

Methicillin-resistant Staphylococcus aureus portends a poor prognosis after endovascular repair of mycotic aortic aneurysms and aortic graft infections

OBJECTIVE

Mycotic aortic aneurysms and aortic graft infections (aortic infections [AIs]) are rare but highly morbid conditions. Open surgical repair is the "gold standard" treatment, but endovascular repair (EVR) is increasingly being used in the management of AI because of the lower operative morbidity. Multiple organisms are associated with AI, and bacteriology may be an important indication of mortality. We describe the bacteriology and associated outcomes of a group of patients treated with an EVR-first approach for AI.

METHODS

All patients who underwent EVR for native aortic or aortic graft infections between 2005 and 2016 were retrospectively reviewed. Primary end points were 30-day mortality and overall mortality. The primary exposure variable was bacteria species. Logistic regression analysis was used to determine association with mortality. Kaplan-Meier survival analysis was used to estimate survival.

RESULTS

A total of 2038 EVRs were performed in 1989 unique and consecutive patients. Of those, 27 patients had undergone EVR for AI. Thirteen presented ruptured (48%). Eighteen (67%) were hemodynamically unstable. Ten had a gastrointestinal bleed (37%), whereas others presented with abdominal pain (33%), fever (22%), chest or back pain (18.5%), and hemothorax (3.7%). Twenty patients had a positive blood culture (74%), with the most common organism being methicillin-resistant Staphylococcus aureus (MRSA) isolated in 37% (10). Other organisms were Escherichia coli (3), Staphylococcus epidermidis (2), Streptococcus (2), Enterococcus faecalis (1), vancomycin-resistant Enterococcus (1), and Klebsiella (1). Thirteen patients had 4 to 6 weeks of postoperative antibiotic therapy, six of whom died after therapy. Fourteen were prescribed lifelong therapy; 10 died while receiving antibiotics. On univariate analysis for mortality, smoking history (P = .061) and aerodigestive bleeding on presentation (P = .109) approached significance, whereas MRSA infection (P = .001) was strongly associated with increased mortality. On multivariate analysis, MRSA remained a strong, independent predictor of mortality (adjusted odds ratio, 93.2; 95% confidence interval, 1.9-4643; P = .023). Overall 30-day mortality was 11%, all MRSA positive. At mean follow-up of 17.4 ± 28 months, overall mortality was 59%. Overall survival at 1 year, 3 years, and 5 years was 49%, 31%, and 23%. Kaplan-Meier survival analysis demonstrated that MRSA-positive patients had a significantly lower survival compared with other pathogens (1-year, 20% vs 71%; 5-year, 0% vs 44%; P = .0009).

CONCLUSIONS

In our series of AI, the most commonly isolated organism was MRSA. MRSA is highly virulent and is associated with increased mortality compared with all other organisms, regardless of treatment. Given our results, EVR for MRSA-positive AI was not a durable treatment option.

Surgery for Acute Presentation of Thoracoabdominal Aortic Disease

Thoracoabdominal aortic aneurysms are most commonly asymptomatic until there is either an impending aortic catastrophe or one that has already occurred. While open surgery remains the gold-standard method for repair, modern technology has led to the development of less invasive endovascular devices and techniques. We provide an expert review of open and endovascular therapies for 3 highly lethal thoracoabdominal aortic emergencies in order to highlight expectations for both short- and long-term outcomes in an era of evolving technology and improvements in patient evaluation and postoperative care. Open repair of ruptured thoracoabdominal aortic aneurysms is associated with a dramatic increase in all postoperative complications, even in specialized aortic surgery centers. Mycotic thoracic aortic aneurysms are highly lethal if surgical treatment is not initiated quickly as they have a propensity toward rapid growth and fatal rupture. Thoracic endovascular aortic repair is well-suited for the treatment of acute complicated type B aortic dissection with outcomes superior to open repair in some centers. Acute aortic events associated with thoracoabdominal aneurysms represent technically challenging situations that require rapid diagnosis and treatment to avoid a fatal outcome. Endovascular techniques have evolved as a viable alternative therapy for acute complicated type B aortic dissection or as a bridge to more definitive repair in the setting of infection or rupture.

Primary Infected Aortic Aneurysm: Clinical Presentation, Pathogen, and Outcome

PURPOSE

Infected aneurysm of the aorta and adjacent arteries is rarely occurring and can be fatal without surgical intervention. Within the medical community, the most efficacious treatment strategy to address infected aortic aneurysm remains controversial. In this study, we have reviewed our treatment experience with 109 patients.

METHODS

We included in our study all consecutive patients treated for primary infected aortic aneurysm at our facility between 1995 and 2011. Aneurysm-related mortality was defined as the presence of in-hospital and late mortality related to infection or postoperative complications.

RESULTS

The median patient age was 72 years (range, 35-88), and 87 (80%) were male. Pathogen was isolated in 101 patients, and the most common microorganism identified was non-typhoid Salmonella in 61 (60%), followed by Staphylococcus aureus in 16 (16%) and Streptococci species in 7 (7%). Eighty-five (78%) patients underwent surgical treatment. Surgery included open repair with in-situ graft replacement in 77 (71%) and endovascular repair in 8 (7%). The aneurysm-related mortality rate was 67% in medically treated and 21% in surgically treated patients, with a median follow-up duration of 31.5 months (range 1-189). Additionally, risk factors for aneurysm-related mortality included old age, chronic lung disease, psoas muscle abscess, short duration of preoperative antibiotics, no operation, and probably endovascular repair.

CONCLUSIONS

Non-typhoid Salmonella was the most common pathogen found in our study group patients with infected aortic aneurysm. It appears that prolonged preoperative antibiotic treatment followed by open in-situ graft replacement remains the preferred and most effective treatment strategy.

KEY WORDS

Infected aortic aneurysm; Outcome; Pathogen; Surgery.

Outcomes of Open Repair of Mycotic Descending Thoracic and Thoracoabdominal Aortic Aneurysms

BACKGROUND

The purpose of this study was to evaluate the short- and intermediate-term outcomes of open repair of mycotic thoracic and thoracoabdominal aneurysms. Contemporary surgical and perioperative techniques were utilized.

METHODS

From November 1997 to May 2014, 14 consecutive patients underwent open repair of descending thoracic (n = 9, 64.3%) and thoracoabdominal (n = 5, 35.7%) mycotic aortic aneurysms. All procedures were performed through the left side of the chest. Infected tissue was completely debrided and excised. Aortic continuity was restored in situ with a Dacron prosthesis (Macquet Corp, Oakland, NJ). Soft tissue coverage of the prosthesis was performed when anatomy and patient condition permitted. Perioperative outcomes, intermediate-term survival, and reinfection rates were examined.

RESULTS

All patients presented with either aneurysm-related symptoms or a clinical picture of sepsis. Diagnosis was confirmed utilizing computed tomography imaging. Mean age was 66 ± 13 years, 8 patients (57.1%) were male, and mean aneurysm size was 5.9 ± 1.3 cm. All patients were hypertensive, 3 (21.4%) had prior coronary revascularization, 7 (50%) had chronic pulmonary disease, 5 (35.7%) had diabetes mellitus, and 2 (14.3%) had end-stage renal disease requiring dialysis. Twelve patients (85.7%) had aneurysm-related pain, and 9 (64.3%) of them had contained rupture. Mean time from onset of illness to surgery was 36 days (range, 0 to 153). On preoperative blood cultures, 4 (28.6%) grew Staphylococcus aureus, 4 (28.6%) grew gram negative organisms, 2 (14.3%) grew mycobacterium, and 4 cultures (28.6%) had negative results. Empiric broad-spectrum antibiotics were initiated on all patients and adjusted based on final cultures. A majority of patients underwent repair utilizing a clamp-and-sew technique (n = 10, 71.4%); the remainder (n = 4, 28.6%) required repair under profound hypothermic circulatory arrest. After radical debridement of the infected tissue, grafts were placed in the normal anatomic position; 6 (42.9%) patients had additional soft tissue coverage, 5 (35.7%) utilizing an omental flap and 1 (7.1%), a serratus muscle flap. There was 1 in-hospital death (7.1%) secondary to ischemic bowel. Four patients (28.6%) required tracheostomy, and 1 (7.1%) had recurrent nerve injury. None of the patients incurred spinal cord injury, stroke, or new onset renal failure requiring dialysis. After surgery, all patients were given 6 weeks of intravenous antibiotics. Lifelong suppression therapy was maintained with oral antibiotics. There were no episodes of prosthetic graft infection on follow-up. Univariate analysis revealed that New York Heart Association functional class, diabetes, and preoperative renal dysfunction were preoperative risk factors for major adverse events. Mean follow-up time was 26.5 months (median 8.2; range, 1 to 142). Actuarial 5-year survival was 71%.

CONCLUSIONS

Open repair of mycotic descending thoracic and thoracoabdominal aortic aneurysms remains the gold standard of therapy. Aggressive intraoperative debridement with in situ prosthetic reconstruction permits a high rate of success in this very high risk cohort of patients. Lifelong antibiotic suppression therapy may prevent late prosthetic graft infection.