Effect of systemic B-type natriuretic peptide on cardiac vagal motoneuron activity

Cardiovascular Autonomic Dysfunction in Chronic Kidney Disease: a Comprehensive Review

Cardiovascular autonomic dysfunction is a major complication of chronic kidney disease (CKD), likely contributing to the high incidence of cardiovascular mortality in this patient population. In addition to adrenergic overdrive in affected individuals, clinical and experimental evidence now strongly indicates the presence of impaired reflex control of both sympathetic and parasympathetic outflow to the heart and vasculature. Although the principal underlying mechanisms are not completely understood, potential involvements of altered baroreceptor, cardiopulmonary, and chemoreceptor reflex function, along with factors including but not limited to increased renin-angiotensin-aldosterone system activity, activation of the renal afferents and cardiovascular structural remodeling have been suggested. This review therefore analyzes potential mechanisms underpinning autonomic imbalance in CKD, covers results accumulated thus far on cardiovascular autonomic function studies in clinical and experimental renal failure, discusses the role of current interventional and therapeutic strategies in ameliorating autonomic deficits associated with chronic renal dysfunction, and identifies gaps in our knowledge of neural mechanisms driving cardiovascular disease in CKD.

N-Terminal Fragment of Pro B-type Natriuretic Peptide as a Marker of Contrast-Induced Nephropathy After Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction

Contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) is frequent and associated with long-term renal impairment and mortality. Early markers of CIN are needed to improve risk stratification. We aimed to assess whether N-terminal fragment of pro B-type natriuretic peptide (Nt-proBNP) could be associated with CIN. From the French regional RICO survey, all the consecutive patients who underwent primary PCI for STEMI, from January 1, 2001, to December 3, 2013, were included. Nt-proBNP circulating levels were assessed on admission. CIN was defined as an increase in serum creatinine >26.5 μmol/L or >50% within 48 to 72 hours after PCI (KDIGO criteria). Of the 1,243 patients included, CIN occurred in 130 patients (10.4%). Nt-proBNP levels were 5 times greater in patients who developed CIN than without CIN (1,275 [435 to 4,022] vs 247 [79 to 986] pg/mL, p <0.001). Hospital mortality rate was markedly higher in patients with CIN (6.9% vs 1.1%, p <0.001). Nt-proBNP levels were univariate predictors for CIN as were age, hypertension, diabetes, smoking, previous stroke, heart rate, impaired left ventricular ejection fraction C-reactive protein, history of renal failure, anemia, and estimated glomerular filtration rate <30 ml/min/1.73 m(2) at baseline. Nt-proBNP levels remained strongly associated with the occurrence of CIN even after adjustment for risk factors, treatments, clinical and biological variables (odds ratio 1.99, 95% confidence interval 1.49 to 2.66). Net reclassification improvement was achieved by the addition of Nt-proBNP to the risk model (p = 0.003). In conclusion, from this large contemporary prospective study in nonselected population, our work suggests that Nt-proBNP levels at admission could help to identify patients at risk of CIN beyond traditional risk factors.

High N-terminal pro-B-type natriuretic peptide levels are associated with reduced heart rate variability in acute myocardial infarction

Aim

We investigated the relationships between the autonomic nervous system, as assessed by heart rate variability (HRV) and levels of N-terminal Pro-B-type Natriuretic Peptide (Nt-proBNP) in patients with acute myocardial infarction (MI).

Methods and Results

The mean of standard deviation of RR intervals (SDNN), the percentage of RR intervals with >50 ms variation (pNN50), square root of mean squared differences of successive RR intervals (rMSSD), and frequency domain parameters (total power (TP), high frequency and low frequency power ratio (LF/HF)) were assessed by 24 h Holter ECG monitoring. 1018 consecutive patients admitted <24 h for an acute MI were included. Plasma Nt-proBNP (Elecsys, Roche) was measured from blood samples taken on admission. The median (IQR) Nt-proBNP level was 681(159–2432) pmol/L. Patients with the highest quartile of Nt-proBNP were older, with higher rate of risk factors and lower ejection fraction. The highest Nt-proBNP quartile group had the lowest SDNN, LF/HF and total power but similar pNN50 and rMSSD levels. Nt-proBNP levels correlated negatively with SDNN (r = −0.19, p<0.001), LF/HF (r = −0.37, p<0.001), and LF (r = −0.29, p<0.001) but not HF (r = −0.043, p = 0.172). Multiple regression analysis showed that plasma propeptide levels remained predictive of LF/HF (B(SE) = −0.065(0.015), p<0.001)), even after adjustment for confounders.

Conclusions

In conclusion, our population-based study highlights the importance of Nt-proBNP levels to predict decreased HRV after acute MI.