Clinical Characteristics, Treatment Strategies, and Prognostic Factors of Infectious Arterial Diseases: A Single-Center, Real-World, Ambispective Observational Cohort Study

Vascular infections encompass a heterogeneous group of severe infectious diseases involving the arterial wall, vascular grafts, or endografts, including infectious aortitis, infected arterial aneurysms, vascular graft and endograft infections, and fistula-associated vascular infections. These conditions are associated with substantial morbidity and mortality and remain challenging with respect to etiological diagnosis, assessment of disease activity, therapeutic decision-making, and prediction of recurrence and long-term outcomes.

The CnZS-VI Cohort is an ambispective observational cohort established at Zhongshan Hospital, Fudan University. The study is designed as a longitudinal clinical research platform integrating standardized clinical data, microbiological investigations, molecular diagnostics, imaging, treatment information, outcome assessment, and longitudinal biospecimen collection. Patients with suspected or confirmed vascular infections will be included and followed longitudinally. In addition to characterization of the overall disease spectrum, the cohort will serve as a platform for multiple nested diagnostic, prognostic, microbiological, imaging, and translational studies.

Etiological diagnosis and evaluation of diagnostic technologies constitute a major focus of the cohort. Conventional microbiological methods, including blood culture, operative specimen culture, histopathology, and pathogen-specific serological testing, will be evaluated together with emerging molecular diagnostic technologies. Particular attention will be given to blood-based pathogen detection as a form of liquid biopsy, including metagenomic and targeted sequencing approaches where available. Diagnostic yield, incremental diagnostic value, time to etiological diagnosis, concordance between blood and local-site specimens, and the clinical impact of different diagnostic strategies will be investigated. Operative tissue and prosthetic material, when available, will provide an important reference for evaluating blood-based diagnostic approaches.

The cohort will also investigate dynamic biomarkers for disease activity and prognosis. Serial blood samples obtained during diagnosis, treatment, and follow-up may be used to characterize changes in pathogen-derived signals and host-response biomarkers. Their associations with microbiological clearance, treatment response, persistent infection, recurrence, reoperation, and mortality will be explored. The long-term objective is to develop integrated diagnostic and prognostic models combining clinical, microbiological, molecular, imaging, and host-response information.

A further research focus is the role of 18F-FDG PET/CT and other imaging modalities in both diagnosis and longitudinal monitoring. The diagnostic performance and incremental value of PET/CT, particularly in patients with inconclusive conventional imaging, will be evaluated. Where serial PET/CT examinations are clinically available, changes in metabolic activity and imaging patterns will be studied in relation to treatment response, residual infection, recurrence, and prognosis. Quantitative and semi-quantitative imaging parameters may be integrated with microbiological and biomarker data to investigate whether multimodal assessment can improve disease classification and therapeutic monitoring.