How to determine adequate antibiotic therapy after surgical repair of mycotic Aneurysm?: the role of serum C-reactive protein level as a predictor

P0145 

Abstract Submission 

Siwon Oh (1), muhyung Heo (1), Seyeon Jeon (1), suryeun chung (1), Yang Hyun Cho (1), Dong Seop Jeong (1), Wook Sung Kim (1), Kiick Sung (1)

(1) Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University, Seoul, NA

Siwon Oh    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

muhyung Heo    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Seyeon Jeon    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

suryeun chung    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Yang Hyun Cho    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Dong Seop Jeong    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Wook Sung Kim    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Kiick Sung    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Siwon Oh    -  Contact Me
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University

Objective
To prevent the abuse and misuse of antibiotic therapy, C-reactive protein (CRP) has been widely used as a marker for the diagnosis and treatment of infectious diseases. However, there are limited studies on this subject in the mycotic aneurysms. We investigated the prognosis based on serum CRP levels after surgery and antibiotic therapy in mycotic aneurysms.

Methods
The retrospective study, conducted at a single center, involved 56 patients treated for mycotic aneurysm of the ascending aorta and aortic arch (n=18), descending thoracic aorta (n=25), and thoracoabdominal aorta (n=13) from March 2003 to June 2023. Patients were considered responsive to antibiotic treatment based on clinical improvement, including the resolution of symptoms, a decrease in serum infectious markers, and the absence of microbial growth in blood after the control of infection. The duration of postoperative antibiotics was determined by the causative bacterial strain. CRP levels were measured at the discontinuation of antibiotic therapy after surgery. Clinical outcomes, including mortality and recurrent infection, underwent meticulous examination during the follow-up period. The relationship between CRP levels and the recurrence of aortic infection was assessed using the area under the curve (AUC) of the receiver operating characteristic.

Results
The mean age of the participants was 69.8 ± 8.2 years, and 40 (71.4%) were male. Complications, such as stent graft infection or aortoesophageal fistula, occurred in 8 (14.3%) patients after endovascular repair. Emergency operations were performed in 8 (14.3%) patients who presented with a rupture of the aorta or massive bleeding. The causative microorganism was identified in all but 10 patients, with staphylococcus and enterococcus being the prevalent bacteria. Most patients underwent in-situ replacement, and 10 utilized the aorta homograft. The median follow-up duration was 34 months. Early mortality occurred in 4 patients (7.1%), and late mortality in 2 patients (3.6%). Without early mortality cases and tuberculosis patients (n=48), 43 patients finally discontinued the antibiotics. Among them, 8 patients (18%) experienced a recurrence of infection. An elevated CRP level at the time of antibiotic discontinuation was identified as a risk factor for recurrence in multivariable analysis (hazard ratio 3.23, p=0.041). The area under the curve (AUC) of the receiver operating characteristic was 0.73, with a cut-off value of 2.64 mg/dL. The five-year recurrence-free survival for patients with CRP levels under 2 mg/dL was 73.2%, whereas for those with CRP levels exceeding 2 mg/dL, it was 21.8% (p<0.001).

Conclusion
CRP levels at the time of antibiotic discontinuation post-aortic surgery could be a predictor of infection recurrence. Monitoring CRP levels postoperatively offers a valuable clinical tool for risk assessment.

Natural History/Follow-Up