Identification of risk factors associated with oral 5-aminolevulinic acid-induced hypotension in photodynamic diagnosis for non-muscle invasive bladder cancer: a multicenter retrospective study

BACKGROUND: To investigate risk factors for orally administered 5-aminolevulinic acid (ALA)-induced hypotension for bladder cancer patients receiving photodynamic diagnosis (PDD)-assisted transurethral resection of bladder tumor (TURBT). METHODS: Patients were categorized into two groups intraoperatively: a hypotensive group (minimum systolic blood pressure (SBP) ≤80 mmHg) and a non-hypotensive group (minimum SBP > 80 mmHg). We examined differences between the hypotensive group and non-hypotensive groups to identify clinical risk of ALA-induced hypotension using multivariate logistic regression analysis and decision tree analysis. RESULTS: Among 282 cases with ALA-PDD-assisted TURBT from three institutions who were screened, 245 patients were included in the final analysis. In total, 156 patients (63.7%) showed any grade of hypotension during ALA-PDD-assisted TURBT. General anesthesia and spinal anesthesia were induced intraoperatively in 113 patients (46.1%) and 132 patients (53.9%), respectively. Median SBP at baseline (before taking ALA) and at the beginning of anesthesia was 127 mmHg (range, 69–186 mmHg) and 124 mmHg (range, 69–186 mmHg), respectively. Median minimum SBP during ALA-PDD-assisted TURBT was 75 mmHg (range, 43–140 mmHg). Multivariate logistic regression analysis revealed that history of hypertension (odds ratio (OR) 7.568, p < 0.05) and general anesthesia (OR 14.435, p < 0.05) as significantly associated with an increased risk of hypotension incidence. Use of calcium antagonist showed significant negative associations with hypotension (OR 0.183, p < 0.05). Decision tree analysis showed presence of general anesthesia, age ≥ 74 years and American Society of Anesthesiologists physical status (ASA-PS) ≥2 as the most important discriminators. CONCLUSIONS: General anesthesia and hypertension were independent risk factors related to ALA-induced hypotension. In contrast, use of calcium antagonists was identified as a factor associated with reduced risk of ALA-induced hypotension.