Challenges in obesity and primary aldosteronism: Diagnosis and treatment.

BACKGROUND: Obese patients may have unrecognized primary aldosteronism due to high rates of concomitant hypertension. We hypothesized that obesity impacts the diagnosis and management of patients with primary aldosteronism. METHODS: We conducted a retrospective analysis of all primary aldosteronism patients (n = 418) who underwent adrenal vein sampling (1997-2017). Patients were classified by body mass index as obese (body mass index ≥35) or nonobese (body mass index <35) and diagnostic evaluation was compared between groups. Within the operative cohort (n = 285), primary outcomes were changes in both blood pressure and antihypertensive medications after adrenalectomy. Secondary outcome was clinical resolution by Primary Aldosteronism Surgery Outcomes criteria. RESULTS: Thirty-five percent of patients were obese. Obese patients were more likely to be male (67.8% vs 56.1%, P = .025), somewhat younger (51.5 vs 54.4 years old, P < .012), and require more preoperative antihypertensive medications (6.7 vs 5.7, P = .04) than nonobese patients. Obese patients had lesser rates of radiologic evidence of adrenal tumors (68.4 vs 77.9%, P = .038) despite similar rates of lateralization on adrenal vein sampling. In the operative subset, obese patients had somewhat smaller tumors on final pathology (1.1 vs 1.5 cm, P = .014) but similar rates of complete and partial clinical resolution (P = 1.000). CONCLUSION: Obese primary aldosteronism patients have lesser rates of localization by imaging, likely due to smaller tumor size, however, experience similar benefit from adrenalectomy.

Falsely Increased Plasma Lactate Dehydrogenase without Hemolysis Following Transport through Pneumatic Tube System.

BACKGROUND: Lactate dehydrogenase (LDH) is a nonspecific biomarker for diseases including lymphoma. Serum and plasma are generally considered interchangeable for LDH testing. Investigation into falsely increased plasma LDH concentration results led to the hypothesis that a workflow change that included pneumatic tube system (PTS) transportation caused the errors. The following study was conducted to test the hypothesis. METHODS: Plasma and serum separator tube samples were each drawn in duplicate, centrifuged, transported either through the PTS or by hand courier, and evaluated by means of clinical chemistry and hematology assays. Smear slides were made out of the plasma and examined. Aggregate patient results before and after the PTS workflow change were compared. RESULTS: In post-PTS plasma samples, LDH activity was 26%-149% higher. Similarly, white blood cells (WBCs) were 14- to 156-fold higher and platelets were 1- to 13-fold higher. Smear examination revealed dramatically more cells and cell fragments. No significant hemolysis was observed in plasma by chemistry hemolysis indices or hemoglobin testing. These effects were not observed in similarly transported serum samples in gel separator tubes. Aggregate LDH patient results, including moving medians, demonstrated dramatic changes following PTS workflow implementation. CONCLUSIONS: PTS transportation led to falsely increased LDH concentration in plasma. These LDH concentration elevations are not heralded by standard indicators of hemolysis. These errors can be prevented by restricting LDH concentration testing to serum collected in gel separator tubes. Moving patient statistics can effectively detect important testing process changes not revealed by external QC or indices.