Summary Objective To describe clinical practice experience of 11C‐Metomidate PET/CT as an adjunct to adrenal vein sampling (AVS) in the lateralization of aldosterone‐producing adenomas (APA) in primary aldosteronism (PA). Context Accurate lateralization of APA in the setting of PA offers the potential for surgical cure and improved long‐term cardiovascular outcomes. Challenges associated with AVS, the current gold standard lateralization modality, mean that only a small proportion of potentially eligible patients currently make it through to surgery. This has prompted consideration of alternative strategies for lateralization, including the application of novel molecular PET tracers such as 11C‐Metomidate. Design Clinical Service Evaluation/Retrospective audit. Patients Fifteen individuals with a confirmed diagnosis of PA, undergoing lateralization with 11C‐Metomidate PET/CT prior to final clinical decision on surgical vs medical management. Measurements All patients underwent screening aldosterone renin ratio (ARR), followed by confirmatory testing with the seated saline infusion test, according to Endocrine Society Clinical Practice Guidelines. Adrenal glands were imaged using dedicated adrenal CT. 11C‐Metomidate PET/CT was undertaken due to equivocal or failed AVS. Management outcomes were assessed by longitudinal measurement of blood pressure, ARR, number of hypertensive medications following adrenalectomy or institution of medical therapy. Results We describe the individual lateralization and clinical outcomes for 15 patients with PA. Conclusion 11C‐Metomidate PET/CT in conjunction with adrenal CT and AVS provided useful information which aided clinical decision‐making for PA within a multidisciplinary hypertension clinic.

Aim: Many challenges exist in determining true rates of adherence to antihypertensive medications among individuals in a clinic setting. For the first time, we aimed to compare patient-reported antihypertensive adherence with objective evidence using mass spectrometry spot urinalysis in a tertiary referral clinic setting.Methods: A prospective observational single-centre cohort study was performed in a tertiary referral hypertension clinic, encompassing antihypertensive initiation and persistence. Patients were referred with apparent treatment-resistant hypertension or for suspected secondary causes. Participants completed a self-reported assessment of antihypertensive adherence and provided a spot urine sample. The presence of antihypertensive medications and/or their respective metabolites was evaluated using high-performance liquid chromatography tandem mass spectrometry. Patients were determined to be adherent if they demonstrated both self-reported adherence and objective mass spectrometry evidence.Results: Of all 105 eligible participants initially recruited, 73 (69.5%) met the eligibility criteria. Only 27.4% (95% confidence interval 0.2-0.4) of participants demonstrated true adherence to their self-reported antihypertensives, despite 75.3% (0.6-0.8) reporting adherence. Greatest medication adherence was achieved with angiotensin II receptor blockers (61%), with calcium-channel blockers and mineralocorticoid antagonists demonstrating least adherence (38%). Conclusion:In patients attending a tertiary hypertension clinic, the combined use of spot urine mass spectrometry and self-reporting identifies higher rates of nonadherence when compared to either modality alone. Both techniques should be combined for more accurate detection of medication adherence.

PURPOSE: High-dose methotrexate (HDMTX; > 500 mg/m2) is an important component of lymphoma therapy. Serum MTX monitoring at 48 hours is the standard approach to identify those at increased risk of developing MTX toxicity. Our aim was to characterize the incidence of complications and their association with MTX levels. METHODS: A retrospective review of our institutional electronic medical record was conducted to identify patients with lymphoma who received HDMTX between January 1, 2002, and December 31, 2018. We characterized the incidence of acute kidney injury (AKI), intensive care unit (ICU) admission, length of hospital stay (LOS), and 30-day mortality across 48-hour MTX levels. To establish an association between 48-hour MTX levels and the complications listed, we performed chi-square analysis for dichotomous variables and Kruskal-Wallis for nonparametric data. Receiver operator characteristic curve analysis was performed to identify the MTX level where AKI grade ≥ 2 was more likely. Multivariate logistic regression analysis was performed to identify risk factors for this MTX level. RESULTS: We identified 642 patients with 2,804 cycles of HDMTX. The incidence of AKI was 19.1% with AKI grade ≥ 2 making up 21% of cases. Rates of AKI, ICU admission, and 30-day mortality are associated with elevated 48-hour MTX levels. There was a significant increase in median LOS with elevated MTX levels ( P < .001). Receiver operator characteristic curve analysis for AKI grade ≥ 2 demonstrated a 48-hour MTX level threshold of 1.28 μmol/L. Multivariate logistic regression analysis revealed age, male sex, elevated body surface area, higher MTX dose, monotherapy, and first cycle as independent factors. CONCLUSION: Elevated MTX levels are associated with a significant increased rate of AKI, ICU admission, prolonged LOS, and 30-day mortality. Elevated 48-hour MTX levels, particularly > 1.28 μmol/L, should alert clinicians for complications and to initiate measures to reduce MTX levels.

e20035 Background: HDMTX is a vital treatment of lymphoma secondary to central nervous system penetrance. MTX is nephrotoxic and may cause acute kidney injury (AKI). AKI results in delayed MTX elimination, increased hospital length of stay (LOS) and intensive care unit (ICU) stays. Our aim was to characterise the complications and associated 48-hour MTX levels in lymphoma patients undergoing HDMTX. Methods: A retrospective review of the electronic medical record was conducted to identify lymphoma patients who received HDMTX from 1/1/2002 to 12/31/18. We assessed the incidence of AKI using AKIN criteria, ICU admission, and LOS across 48 hour MTX levels per the table. Results: 2704 cycles of HDMTX were identified. The mean age was 64 years, 54% were male and 72.2% received high dose (≥8g/m2). A significant increase in AKI severity (p < 0.0001) and LOS (p < 0.01) occurred with increasing 48 hour MTX levels, (p < 0.001, Table). All 7 patients requiring dialysis had MTX levels > 10. ROC curve analysis for AKI grade ≥ 2 demonstrated a 48 hour MTX level threshold of 1.28 (AUC 0.79) with relative risk of 7.6 (95% CI 5.3-11) and odds ratio of 8.8 (95% CI 5.9-13.1). A significant increase occurred in LOS across escalating 48 hour MTX level subgroups (p < 0.01, Table). A significant rise in ICU admissions occurred with increasing MTX levels ( < 0.01% for MTX < 2 compared to 15% with MTX > 5). Conclusions: Complications of HDMTX are significantly increased with elevated 48 hour MTX levels, particularly with levels > 1 μmol/L. [Table: see text]

Background and Aims High dose Methotrexate (HDMTX) is an important component of several modern oncological/haematological treatment protocols due to its central nervous system penetrance. Nephrotoxicity represents a significant adverse effect and can limit therapeutic options. Therefore, strategies to prevent this are paramount. Urinary alkalinisation and large volume resuscitation to maintain adequate hydration and urine output are the typical strategies. Urinary alkalinisation prevents tubular precipitation of methotrexate and therefore, a strict urinary pH target of 7 is maintained via a continuous bicarbonate infusion. Method We describe a case report, of Iatrogenic metabolic alkalosis leading to respiratory compromise in a patient receiving HDMTX from Mayo Clinic, Rochester. Results We present the case of a 76-year-old woman with a Diffuse Large B-Cell Lymphoma with CNS involvement who presented for elective admission for her 1st cycle of HDMTX. She received 7g of Methotrexate at dosing of 8 g/m2. She received the standard urinary alkalinisation with pre- and post-hydration. Her baseline HCO3- was 28 mEq/L. Her 48 hour MTX level was elevated at 1.2 so the urinary alkalinisation protocol was continued until &lt;0.1 mcmol/L. On day 4, she developed frequent episodes of apnoea. Her ABG demonstrated a metabolic alkalaemia pH 7.54, pCO 53, pO2 91, HCO3 45. She was transferred to the ICU for close monitoring. Her bicarbonate infusion was discontinued and she received acetazolamide. Her bicarbonate improved to 31 after 12 hours. She had a significant improvement in her respiratory status with no further episodes of apnoea. Her bicarbonate infusion was restarted due to elevated MTX levels. She was discharged home with no further complications. Conclusion Iatrogenic Metabolic alkalosis leading to respiratory compromise represents a rare but important complication of urinary alkalinsation protocols for High-dose Methotrexate therapy.