Endocrine Abstracts

Background: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumours managed with pre-operative alpha+/- beta blockade prior to surgery. These patients are at risk of intra-and postoperative haemodynamic instability. The aim of this project was to review the outcomes of PPGL patients operated on between 2018-2023 at Cardiff and Vale UHB.

Methods: Retrospective case notes (n = 29) review for data collection on baseline demographics, presentation, metanephrines results, pre-operative pharmacotherapy (duration, type, dosage), surgical outcomes and length of stay.

Results: Twenty-one patients had pheochromocytoma, 7- paraganglioma and there was 1 benign tumour (M=18, F=12, mean age 57.1 years old (SD=16.63)). The most common presenting complaint was either hypertensive episodes, headaches, palpitations, or a combination of the 3. All pheochromocytoma patients and 6 (85%) paraganglioma patients had abnormal pre-operative urine/plasma metanephrines. Higher baseline urinary normetadrenalines correlated with a longer length of hospital stay (P = 0.04). Twenty-eight patients were started on alpha-blockade (Phenoxybenzamine (PBZ) n = 23; doxazosin n = 5). The median pre-operative systolic BP was 128mmHg lying and 113mmHg standing. Within the PBZ cohort, 4 patients were also managed with bisoprolol prior to surgery. These patients required higher doses of PBZ preoperatively (median total daily dose 80 mg ranging from 30 mg BD to 60 mg TDS) compared to those on PBZ alone (P = 0.0063) Additionally, the combined alpha and beta-blocked patient cohort (n = 6, PBZ=4, doxazosin = 2) was also found to be more haemodynamically unstable intraoperatively requiring significantly more metaraminol boluses (6.3) compared to the non-beta blocker cohort (3.4 boluses) (P = 0.0260). Interestingly, amongst those 6 alpha- and beta-blocked patients, 4 (67%) were also treated with a calcium channel blocker.

Discussion: In our cohort, PPGL patients on combined alpha- and beta-blockade experienced a higher number of hemodynamic intraoperative instability. Larger prospective studies would be beneficial to establish an up to date evidence-based approach regarding optimal pre-operative preparation of the PPGL patients.