Prognostic prediction models for endovascular abdominal aortic aneurysm repair: protocol for a scoping review

Endovascular aneurysm repair (EVAR) has a marked short-term advantage over open surgical repair in managing abdominal aortic aneurysms (AAA); however, this benefit is lost in the long term. The current trend towards stratified medicine has given rise to diverse prognostic prediction models and scoring systems for EVAR. These models could act as decision support tools that employ patient and operative factors, to improve long-term outcomes. Past literature evaluated and compared model performance for predicting one outcome, for example, mortality. None were deemed competent for clinical application. The proposed study will use a scoping review approach to capture literature on prognostic modelling in EVAR for all predictable outcomes. The results are anticipated to inform future research, identify knowledge gaps, and assist in determining the potential of models for clinical use.

The proposed study will use the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping Reviews as a framework for conducting the review. PubMed Central, Embase and Cochrane Library will be searched and screened for peer-reviewed studies on prognostic modelling for EVAR, published between 2000 and 2022. No limits exist on predictor variables used and outcomes predicted by the model for inclusion, provided they apply to AAA patients managed with EVAR. Data will be abstracted using a charting form based on the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies guidelines and PRISMA guidelines for systematic reviews. The Prediction model Risk of Bias Assessment Tool and the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis checklist will be used to critically appraise included studies.

Since scoping reviews cover secondary data from published literature, ethical approval is not required. The findings will be disseminated via peer-reviewed publications and presentations at key conferences.