Prediction of Atrial Fibrillation by B-type Natriuretic Peptide

Positive relationships between annual changes in salt intake and plasma B-type natriuretic peptide levels in the general population without hypertension and heart diseases

Excessive salt intake causes hypertension and heart diseases. B-type natriuretic peptide (BNP) is a surrogate marker of heart disease, and a slightly elevated BNP level is associated with a poor prognosis. Our previous cross-sectional study demonstrated that plasma BNP has a significant positive association with daily salt intake in the general population. However, the relationship between changes in salt intake and changes in plasma BNP remains unknown. We recruited 3051 participants without hypertension or electrocardiogram abnormalities who underwent annual health check-ups for two consecutive years. Clinical parameters, including plasma BNP, were obtained, and daily salt intake was evaluated using urinary samples. Annual changes in these parameters were calculated. The median plasma BNP level was 12.9 pg/mL, and the daily salt intake was 8.73 ± 1.89 g. The annual changes in plasma BNP and daily salt intake were 4.79 ± 36.38% and 2.01 ± 21.80%, respectively. Participants in the highest quartile of annual changes in daily salt intake showed the largest annual changes in plasma BNP. Annual changes in plasma BNP indicated a significant positive association with daily salt intake. Moreover, multiple linear regression analyses revealed that annual changes in plasma BNP showed a significant positive association with daily salt intake after adjustments. Our study showed a significant positive relationship between annual changes in plasma BNP and annual changes in daily salt intake. The suppression of plasma BNP is therefore induced by salt intake restriction. The monitoring of plasma BNP while reducing salt intake may therefore prevent heart diseases and lead to improved prognoses in the general population without heart diseases.

Preoperative levels of natriuretic peptides and the incidence of postoperative atrial fibrillation after noncardiac surgery: a prospective cohort study

BACKGROUND

Postoperative atrial fibrillation (POAF) is associated with clinically significant short- and long-term complications after noncardiac surgery. Our aim was to describe the incidence of clinically important POAF after noncardiac surgery and establish the prognostic value of N-terminal pro-brain-type natriuretic peptide (NT-proBNP) in this context.

METHODS

The Vascular events In noncardiac Surgery patIents cOhort evaluatioN (VISION) Study was a prospective cohort study involving patients aged 45 years and older who had inpatient noncardiac surgery that was performed between August 2007 and November 2013. We determined 30-day incidence of clinically important POAF (i.e., resulting in angina, congestive heart failure, symptomatic hypotension or requiring treatment) using logistic regression models to analyze the association between preoperative NT-proBNP and POAF.

RESULTS

In 37 664 patients with no history of atrial fibrillation, we found that the incidence of POAF was 1.0% (95% confidence interval [CI] 0.9%-1.1%; 369 events); 3.2% (95% CI 2.3%-4.4%) in patients undergoing major thoracic surgery, 1.3% (95% CI 1.2%-1.5%) in patients undergoing major nonthoracic surgery and 0.2% (95% CI 0.1%-0.3%) in patients undergoing low-risk surgery. In a subgroup of 9789 patients with preoperative NT-proBNP measurements, the biomarker improved the prediction of POAF risk over conventional prognostic factors (likelihood ratio test p < 0.001; fraction of new information from NT-proBNP was 16%). Compared with a reference NT-proBNP measurement set at 100 ng/L, adjusted odds ratios for the occurrence of POAF were 1.31 (95% CI 1.15-1.49) at 200 ng/L, 2.07 (95% CI 1.27-3.36) at 1500 ng/L and 2.39 (95% CI 1.26-4.51) at 3000 ng/L.

INTERPRETATION

We determined that the incidence of clinically important POAF after noncardiac surgery was 1.0%. We also found that preoperative NT-proBNP levels were associated with POAF independent of established prognostic factors. Trial registration: ClinicalTrials.gov, no. NCT00512109.

Salt intake causes B-type natriuretic peptide elevation independently of blood pressure elevation in the general population without hypertension and heart disease

Excessive salt intake causes hypertension and cardiovascular diseases (CVDs). B-type natriuretic peptide (BNP) is synthesized and released from the ventricle, and is a surrogate marker reflecting various CVDs. Moreover, when a slight BNP elevation is shown, it leads to a poor prognosis in the general population. However, the relationship between salt intake and BNP levels in the general population remains unclear, especially in those without hypertension and heart diseases.In this study, we recruited 1404 participants without hypertension and electrocardiogram abnormalities, who received regular annual health check-ups in Japan. Plasma BNP levels were measured, and daily salt intake levels were evaluated using urinary samples. In addition, some clinical parameters were obtained, and the data were cross-sectionally analyzed.The median of plasma BNP levels was 10.50 pg/mL, and daily salt intake was 8.50 ± 1.85 g. When dividing participants into quartiles according to daily salt intake, those with the highest daily salt intake revealed the highest plasma BNP levels. Plasma BNP levels were significantly and positively associated with daily salt intake. Moreover, multiple linear regression analyses revealed that plasma BNP levels showed a significant positive association with daily salt intake levels after adjustments.Plasma BNP levels were significantly and positively associated with daily salt intake after adjustment in the general population. Plasma BNP levels may be a surrogate marker reflecting salt-induced heart diseases.

Indices of left ventricular voltage on electrocardiogram are closely associated with serum cardiac troponin I levels in normotensive Japanese individuals

The high-sensitivity cardiac troponin I (hs-cTnI) in serum can increase due to an increase in left ventricular (LV) overload in individuals with hypertension. Since LV voltage on an electrocardiogram (ECG) reflects LV load, it is possible that LV voltage is closely associated with hs-cTnI in individuals without hypertension. This study investigated the association between LV voltage indices and serum hs-cTnI levels in normotensive Japanese individuals.Subjects who visited the Enshu Hospital for a health check-up were screened for their eligibility. Subjects with renal dysfunction, cancer, active inflammatory disease, or a history of cardiovascular events were excluded, as were subjects with obvious ST segment or T wave abnormality, Wolff-Parkinson-White syndrome, pacemaker implantation, or frequent arrhythmia in the ECG. Exclusion of individuals with hypertension left 803 subjects (54.8 ± 11.3 years) for final inclusion. The R wave voltage in lead V5 (RV5 voltage), the Sokolow-Lyon voltage (a sum of the QRS wave (a complex wave consists of Q, R, and S wave) of the S wave voltage in lead V1 and the R wave voltage in lead V5), and the Cornell product (a product of QRS duration and QRS voltage) were evaluated by ECG as LV voltage indices. Laboratory measurements included serum hs-cTnI levels. Possible associations between indices of LV voltage on ECG and serum hs-cTnI levels were cross-sectionally investigated in the normotensive subjects.The median values [interquartile range] of hs-cTnI and BNP were and 2.1 [1.4-3.0] and 13.8 [7.7-24.9] pg/mL, respectively. Multivariate regression analysis identified that the levels of hs-cTnI, but not BNP, were significantly associated with RV5 voltage (β 0.090, P = .0087), Sokolow-Lyon voltage (β 0.112, P = .0009), and Cornell product (β 0.101, P = .039) after adjustment for possible confounding factors. Moreover, the RV5 voltage, Sokolow-Lyon voltage, and Cornell product were significantly associated with the hs-cTnI levels after adjustment for possible confounding factors including ECG findings (β 0.109, P = .0075; β 0.125, P = .0010; and β 0.096, P = .0116, respectively).Indices of LV voltage in ECG had close associations with serum hs-cTnI levels in normotensive subjects. These findings support that the ECG findings of LV voltage have significant associations with slight myocardial micro-damage even in normotensive subjects.