Risk Factor of Persistent Hypotension Associated with 5-Aminolevulinic Acid: A Single-Institution Retrospective Study

5-Aminolevulinic acid (5-ALA), an amino acid precursor of protoporphyrin IX, is used in the photodynamic diagnosis (PDD) of bladder cancer because it emits fluorescence at specific wavelengths. Severe hypotension has been reported in patients undergoing 5-ALA-based PDD. Previous studies have mainly focused on hypotension occurring immediately after 5-ALA administration. Persistent hypotension lasting beyond the day of administration has also been reported, indicating a need for continued postoperative management. However, the risk factors associated with persistent 5-ALA-induced hypotension remain unclear. This retrospective study aimed to identify the risk factors for persistent hypotension following 5-ALA administration. Among 263 patients who received 5-ALA for PDD of bladder cancer at Yamaguchi University Hospital between April 2018 and March 2022, 183 developed hypotension and were included in the analysis. Patients were classified into a persistent hypotension group (n = 30), comprising those with continued hypotension the following day, and a nonpersistent group (n = 153). Baseline demographics and clinical characteristics were comparable between the groups. In contrast, preoperative hemoglobin levels were significantly lower in the persistent group (p < 0.05). Multivariate logistic regression analysis identified preoperative hemoglobin levels as an independent risk factor for persistent hypotension (odds ratio, 0.76; 95% confidence interval, 0.60-0.97). A hemoglobin concentration of 12.9 g/dL was determined as the cutoff value for predicting the incidence of persistent hypotension using receiver-operating characteristic curve analysis. Although further validation is required, these findings suggest that the preoperative hemoglobin level may serve as a potential indicator for risk stratification of persistent hypotension induced by 5-ALA.