Mid-regional pro-atrial natriuretic peptide and the assessment of volaemic status and differential diagnosis of profound hyponatraemia

Lack of an association between first-trimester concentration of mid-regional pro-atrial natriuretic peptide and risk of early-onset preeclampsia <34 weeks' gestation

AIM

We examined the heart failure biomarker mid-regional pro-atrial natriuretic peptide during the first trimester of pregnancy in relation to early-onset preeclampsia <34 weeks.

MATERIALS AND METHODS

This case-control study included 34 women with singleton pregnancies with a preeclampsia diagnosis and delivery before 34 weeks of gestation who had attended the routine first-trimester ultrasound scan at 11-13+6 weeks of gestation between August 2010 and October 2015 at the Copenhagen University Hospital Rigshospitalet, Denmark, and 91 uncomplicated singleton pregnancies matched by time of the routine first-trimester blood sampling at 8-13+6 weeks. Descriptive statistical analyses were performed for maternal characteristics and obstetric and medical history for the case versus the control group. Concentrations of mid-regional pro-atrial natriuretic peptide, placental growth factor, soluble fms-like tyrosine kinase-1, and pregnancy-associated plasma protein A between early-onset preeclampsia cases and the control group were compared using Students t-test and the Mann-Whitney U test. Biochemical marker concentrations were converted into multiples of the expected median values after adjustment for gestational age.

RESULTS

Mid-regional pro-atrial natriuretic peptide levels were not significantly different between early-onset preeclampsia cases and the control group in the first trimester of pregnancy. As expected, both placental growth factor and pregnancy-associated plasma protein A levels were significantly lower in early-onset preeclampsia, whereas soluble fms-like tyrosine kinase-1 levels were not statistically significantly different.

CONCLUSION

The maternal first-trimester concentration of mid-regional pro-atrial natriuretic peptide, a peptide with multiple biological functions including a relation to cardiovascular disease, was not significantly different in women with early-onset preeclampsia.

Combination of cardiac color Doppler ultrasound, serum MR-ProANP and NT-ProBNP forecasted hypertensive LVH and LFH

To analyze the value of the combined test of the cardiac color Doppler ultrasound, the serum middle receptor pro-atrial natriuretic peptide (MR-ProANP) and the N-terminal pro-brain natriuretic peptide (NT-ProBNP) in forecasting the hypertensive left ventricular hypertrophy (LVH) and left heart failure (LHF). All patients were subjected to cardiac color Doppler ultrasound examination to obtain left atrium volume index (LAVI), left ventricular end-diastolic diameter (LVEDD), early-diastolic peak flow velocity (E), early-diastolic mean flow velocity (e'), early-diastolic peak flow velocity/early-diastolic mean flow velocity (E/e') and left ventricular ejection fraction (LVEF). Biomarkers were performed to obtain serum MR-ProANP and NT-ProBNP concentrations, and statistical analysis was performed. The LVEF was obviously lower than that in the control group (P<0.01). The area under the receiver operating characteristic (ROC) curve (AUC) values of LVEF, E/e', serum MR-ProANP and NT-ProBNP alone were in the range of 0.7-0.8. The AUC, sensitivity and specificity of LVEF and E/e' combined with MR-ProANP and NT-ProBNP to diagnose hypertensive LVH and LHF were 0.892, 89.14% and 78.21%, which were higher than those of single diagnosis. In the heart failure group, LVEF was negatively correlated with serum MR-ProANP and NT-ProBNP concentrations (P<0.05), and E/e' was positively correlated with serum MR-ProANP and NT-ProBNP concentrations (P<0.05). Pump function and ventricular remodeling in patients with hypertensive LVH and LHF are closely related to serum MR-ProANP and NT-ProBNP levels. Combination of the two testing can improve the prediction and diagnostic efficacy of LHF.

Recent advances in small cell lung cancer: the future is now?

Small cell lung cancer is a relevant clinical issue as it is a highly malignant cancer, often diagnosed in advanced stage. Similarly to non-small cell lung cancer, tobacco smoking is currently the main risk factor. Its incidence, at least in males, has declined over the past decades, due to the worldwide decreased percentage of active smokers. The typical small cells of this tumor type are characterized by a high Proliferation Index, chromosomal deletions such as 3p(14-23) involving the tumor-suppressor gene FHIT, alterations of the MYC or Notch family proteins and the frequent expression of neuroendocrine markers. The combination of thoracic radiotherapy and chemotherapy is the standard treatment for limited stage disease, while platinum-based chemotherapy is the most effective choice for extensive stage disease. Unfortunately, whatever chemotherapy is used, the results are disappointing. No regimen has proved to be effective in the long run, indeed small cell lung cancer rapidly progresses after a frequent initial strong response, and the mortality rate remains still high. The advent of immunotherapy is actually changing the landscape in oncology. As well as in other cancers, recent trials have demonstrated the efficacy of the combination of immune checkpoint inhibitors and chemotherapy, opening new perspectives for the future of our patients.

Can treatment response to SGLT2-inhibitors in syndrome of inappropriate antidiuresis be predicted by copeptin, natriuretic peptides and inflammatory markers?

PURPOSE

The syndrome of inappropriate antidiuresis (SIAD) is the main cause of hyponatremia and the SGLT2-inhibitor empagliflozin is a promising new treatment option. A biomarker predicting treatment response could optimize treatment success.

MATERIALS AND METHODS

Secondary analysis of a trial including 84 hospitalized patients with SIAD-induced hyponatremia. Patients were randomized to four days of treatment with empagliflozin 25 mg/d (n = 43) or placebo (n = 41) with both groups receiving fluid restriction <1000 ml/d. Baseline levels of copeptin, the natriuretic peptides MR-proANP and NT-proBNP and C-reactive protein (CRP) were evaluated as predictors for treatment response defined as absolute sodium change, using linear regression models. Additionally, urinary sodium was assessed as predictor for non-response to fluid restriction alone by constructing the receiver-operating characteristic (ROC) curve.

RESULTS

No clinically relevant predictive value for treatment response to empagliflozin could be found for copeptin, MR-proANP, NT-proBNP or CRP. A urinary sodium cut-off of >76 mmol/l led to a specificity of 91.7% [95% confidence interval (CI): 75%, 100%] and sensitivity of 51.9% [33.3%, 70.4%] to predict non-response to fluid restriction alone.

CONCLUSIONS

Based on our data, no biomarker could be identified as predictor for treatment response to empagliflozin. Urinary sodium was confirmed as a good marker for non-response to fluid restriction in SIAD patients. Clinical trial registration: ClinicalTrials.gov (Number: NCT02874807).

Association between copeptin levels and treatment responses to hypertonic saline infusion in patients with symptomatic hyponatremia: a prospective cohort study

Background

Copeptin is secreted in equimolar amounts as arginine vasopressin, main hormone regulating body fluid homeostasis. A recent study reported a copeptin-based classification of osmoregulatory defects in syndromes of inappropriate antidiuresis that may aid in prediction of therapeutic success. We investigated usefulness of copeptin for differentiating etiologies of hyponatremia and predicting efficacy and safety of hypertonic saline treatment in hyponatremic patients.

Methods

We performed a multicenter, prospective cohort study of 100 inpatients with symptomatic hyponatremia (corrected serum sodium [sNa] ≤ 125 mmol/L) treated with hypertonic saline. Copeptin levels were measured at baseline and 24 hours after treatment initiation, and patients were classified as being below or above median of copeptin at baseline or at 24 hours, respectively. Correlations between target, under correction, and overcorrection rates of sNa within 24 hours/24–48 hours and copeptin levels at baseline/24 hours were analyzed.

Results

Mean sNa and median copeptin levels were 117.9 and 16.9 pmol/L, respectively. Ratio of copeptin-to-urine sodium allowed for an improved differentiation among some (insufficient effective circulatory volume), but not all hyponatremia etiologic subgroups. Patients with below-median copeptin levels at baseline achieved a higher target correction rate in 6/24 hours (odds ratio [OR], 2.97; p = 0.02/OR, 6.21; p = 0.006). Patients with below-median copeptin levels 24 hours after treatment showed a higher overcorrection rate in next 24 hours (OR, 18.00, p = 0.02).

Conclusion

There is a limited diagnostic utility of copeptin for differential diagnosis of hyponatremia. However, copeptin might be useful for predicting responses to hypertonic saline treatment in hyponatremic patients.

Diagnosis and Treatment of Hyponatremia: Compilation of the Guidelines

Hyponatremia is a common water balance disorder that often poses a diagnostic or therapeutic challenge. Therefore, guidelines were developed by professional organizations, one from within the United States (2013) and one from within Europe (2014). This review discusses the diagnosis and treatment of hyponatremia, comparing the two guidelines and highlighting recent developments. Diagnostically, the initial step is to differentiate hypotonic from nonhypotonic hyponatremia. Hypotonic hyponatremia is further differentiated on the basis of urine osmolality, urine sodium level, and volume status. Recently identified parameters, including fractional uric acid excretion and plasma copeptin concentration, may further improve the diagnostic approach. The treatment for hyponatremia is chosen on the basis of duration and symptoms. For acute or severely symptomatic hyponatremia, both guidelines adopted the approach of giving a bolus of hypertonic saline. Although fluid restriction remains the first-line treatment for most forms of chronic hyponatremia, therapy to increase renal free water excretion is often necessary. Vasopressin receptor antagonists, urea, and loop diuretics serve this purpose, but received different recommendations in the two guidelines. Such discrepancies may relate to different interpretations of the limited evidence or differences in guideline methodology. Nevertheless, the development of guidelines has been important in advancing this evolving field.

Predictors of nonresponse to fluid restriction in hyponatraemia due to the syndrome of inappropriate antidiuresis

BACKGROUND

Fluid restriction (FR), the first-line treatment for hyponatraemia due to the syndrome of inappropriate antidiuresis (SIAD), often does not lead to successful correction of hyponatraemia. Therefore, predictive markers of treatment response are desirable. We evaluated routinely measured serum (s) and urine (u) parameters, s-copeptin and s-mid-regional pro-atrial natriuretic peptide (s-MR-proANP), as possible predictors of FR response.

METHODS

In this prospective observational study, we included patients with profound hyponatraemia (s-sodium <125 mmol L^-1 ) due to SIAD. Patients were classified as FR responders (increase in s-sodium concentration of >3 mmol L^-1 within 24 h) or nonresponders (increase of ≤3 mmol L^-1 within 24 h). Initial laboratory parameters were compared between groups with logistic regression analysis.

RESULTS

Of 106 SIAD patients analysed, 82 underwent treatment with FR; 48 (59%) patients showed a successful response to FR and 34 (41%) were considered nonresponders. High levels of u-sodium and u-osmolality were significantly associated with nonresponse to FR [odds ratio (OR) 15.0, 95% confidence interval (CI) 2.4-95.8, P = 0.004 and OR 34.8, 95% CI 1.2-1038.8, P = 0.041, respectively). The association of u-sodium and nonresponse remained significant also after adjustment for diuretic use. Lower levels of s-MR-proANP were associated with nonresponse (OR 0.03, 95% CI 0.003-0.3, P = 0.004), whereas s-copeptin was not significantly associated with response to FR.

CONCLUSION

Easily measured laboratory parameters, especially u-sodium, correlate with therapeutic response and identify patients most likely to fail to respond to FR. Measurement of these parameters may facilitate early treatment choice in patients with SIAD.