Oral 5-aminolevulinic acid induced Photodynamic Diagnostic Ureterorenoscopy--does the blood pressure require monitoring?
BACKGROUND
Photodynamic Diagnosis has been proven to improve detection of superficial bladder cancer and improve visualisation of resection margins. The use of 5-aminolevulinic acid as the photosensitising agent has been associated with side effects, specifically hypotension. We aimed to evaluate the effect of oral 5-ALA on the blood pressure in a group of patient who underwent Photodynamic Diagnostic Ureterorenoscopy.


METHODS
We carried out an observational study on all patients who underwent PDD-Ureterorenoscopy with oral 5-ALA between July 2009 and September 2011. Pre-administration, hourly post-administration and hourly post-operative blood pressures were noted. Mean arterial blood pressure and the threshold for cerebral ischaemia were calculated as well.


RESULTS
The study includes thirty-eight procedures which involved twenty-four patients with a mean age of 74 (SD±16.95). Hypotension was defined as <80% of the systolic or diastolic baseline blood pressure. Twenty patients were hypotensive pre-operatively after the ingestion of 5-ALA while 21 patients were hypotensive post-operatively. Three patients crossed their MAP threshold pre-operatively and were symptomatic. Fast infusion of intravenous fluids improved their symptoms.


CONCLUSION
Hypotension is a common occurrence after the ingestion of 5-ALA. Patients undergoing PDD Ureterorenoscopy should have their blood pressure monitored closely after the ingestion of 5-ALA.