Risk Factors for Intraoperative Hypotension Associated with the Use of Oral 5-Aminolevulinic Acid as a Photodynamic Diagnostic Agent in Transurethral Resection of Bladder Tumors: A Meta-Analysis

• Identified key risk factors for oral 5-ALA-induced intraoperative hypotension • Meta-analysis reveals aging increases hypotension risk during TURBT • Female sex significantly linked to higher intraoperative hypotension • General anesthesia raises hypotension risk more than spinal anaesthesia • Comorbidity of hypertension elevates hypotension risk with oral 5-ALA use The photodynamic diagnostic agent oral 5-aminolevulinic acid (5-ALA) promotes the selective accumulation of protoporphyrin IX in tumor cells and is used for intraoperative visualization of tumor tissue in the diagnosis and treatment of non-invasive bladder cancer confined to the muscle. However, the use of oral 5-ALA in photodynamic diagnosis has been reported to cause intraoperative hypotension during urologic surgery. Therefore, this meta-analysis was conducted to identify risk factors for intraoperative hypotension associated with oral 5-ALA use during transurethral resection of bladder tumors (TURBT) performed for non-invasive bladder cancer in the muscle layer. This meta-analysis was conducted on studies investigating risk factors for intraoperative hypotension during TURBT using oral 5-ALA. Relevant studies published in PubMed, Scopus, Cochrane Library, and Ichu-shi databases through June 14, 2024, were selected. A meta-analysis was performed on risk factors evaluated in at least four studies. We found that age (mean difference: 3.55; 95% confidence interval [CI]: 1.76—5.35), female sex (odds ratio [OR]: 1.60; 95% CI: 1.16—2.24), a comorbidity of hypertension (OR: 1.57; 95% CI: 1.18—2.07), Renin–Angiotensin System inhibitors (OR: 1.67; 95% CI: 1.25—2.22), and use of general anesthesia (OR: 6.08; 95% CI: 3.17—11.6) were significantly associated with the risk of intraoperative hypotension. This meta-analysis elucidated the risk factors for severe hypotension during TURBT. Consequently, when oral 5-ALA is used in TURBT, the patient background should be assessed, and modifiable risk factors should be addressed to prevent the development of severe hypotension.