Christos Argyropoulos MD, PhDJun 16, 2023

Fresh from the press, my most recent collaboration about

Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management https://www.mdpi.com/2344126 #mdpijcm via @JCM_MDPI

@MRoumelioti
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Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management

Pseudohyponatremia remains a problem for clinical laboratories. In this study, we analyzed the mechanisms, diagnosis, clinical consequences, and conditions associated with pseudohyponatremia, and future developments for its elimination. The two methods involved assess the serum sodium concentration ([Na]S) using sodium ion-specific electrodes: (a) a direct ion-specific electrode (ISE), and (b) an indirect ISE. A direct ISE does not require dilution of a sample prior to its measurement, whereas an indirect ISE needs pre-measurement sample dilution. [Na]S measurements using an indirect ISE are influenced by abnormal concentrations of serum proteins or lipids. Pseudohyponatremia occurs when the [Na]S is measured with an indirect ISE and the serum solid content concentrations are elevated, resulting in reciprocal depressions in serum water and [Na]S values. Pseudonormonatremia or pseudohypernatremia are encountered in hypoproteinemic patients who have a decreased plasma solids content. Three mechanisms are responsible for pseudohyponatremia: (a) a reduction in the [Na]S due to lower serum water and sodium concentrations, the electrolyte exclusion effect; (b) an increase in the measured sample’s water concentration post-dilution to a greater extent when compared to normal serum, lowering the [Na] in this sample; (c) when serum hyperviscosity reduces serum delivery to the device that apportions serum and diluent. Patients with pseudohyponatremia and a normal [Na]S do not develop water movement across cell membranes and clinical manifestations of hypotonic hyponatremia. Pseudohyponatremia does not require treatment to address the [Na]S, making any inadvertent correction treatment potentially detrimental.

MDPI
Viet Le, MPAS PA-C FACC FAHAMay 4, 2023
Frequency and Outcomes of Patients Presenting with Non-ST Elevation Myocardial Infarction (NSTEMI) without Standard Modifiable Risk Factors: A US Healthcare Experience https://www.mdpi.com/2277476 #mdpijcm via @JCM_MDPI @Intermountain @KirkKnowlton @JBMuhlesteinMD @KnightSNPs
Frequency and Outcomes of Patients Presenting with Non-ST Elevation Myocardial Infarction (NSTEMI) without Standard Modifiable Risk Factors: A US Healthcare Experience

Patients with ST-elevation myocardial infarction (STEMI), but without standard modifiable risk factors (SMuRF-less), are surprisingly common and appear to have a worse, or at best similar, short-term prognosis. However, relatively little attention has been paid to the prevalence and prognosis of SMuRF-less patients with non-STEMI (NSTEMI). The aim of our study was to identify the proportion and outcomes of SMuRF-less NSTEMI patients in a large US healthcare population. Patients with NSTEMI between 2001–2021 presenting to Intermountain Healthcare hospitals and catheterization laboratories were included. SMuRF-less status was defined as no clinical diagnosis of, or treatment for, hypertension, hyperlipidemia, diabetes, and smoking. Outcomes were assessed at 60 days and long-term for major adverse cardiovascular events (MACE: death, myocardial infarction, and heart failure hospitalization). Multivariable Cox proportional hazard regression was used to determine MACE hazard ratios (HR) for SMuRF-less versus patients with SMuRF. NSTEMI patients totaled 8196, of which 1458 (17.8%) were SMuRF-less. SMuRF-less patients were younger, more frequently male, had fewer comorbidities, and were slightly less likely to have revascularization. For SMuRF-less patients, 60-day MACE outcomes were lower (adj HR = 0.55, p < 0.0001), and this persisted for long-term MACE outcomes (adj HR = 0.64, p < 0.0001) and for each of its components. In this large US healthcare population, SMuRF-less NSTEMI presentation, as with STEMI presentation, was found to be common (17.8%). However, unlike STEMI reports, short- and long-term outcomes were better for SMuRF-less patients. Further studies to increase understanding of risk factors and preventive measures for NSTEMI in SMuRF-less patients are indicated.

MDPI