Utility of B-natriuretic peptide levels in identifying patients with left ventricular systolic or diastolic dysfunction

PURPOSE: Although echocardiography is important for making the diagnosis of left ventricular dysfunction, its cost and lack of availability limit its use as a routine screening test. B-Natriuretic peptide levels accurately reflect ventricular pressure, and preliminary studies with a rapid assay have found that levels are sensitive and specific for diagnosing heart failure in patients with dyspnea. We hypothesized that B-natriuretic peptide levels obtained through the use of a rapid assay should correlate with echocardiographic abnormalities of ventricular function. SUBJECTS AND METHODS: We studied 400 patients who were referred for echocardiography at the San Diego Veteran's Healthcare System between June and August 2000 to evaluate ventricular function. B-natriuretic peptide levels were measured by a point-of-care immunoassay; cardiologists assessing left ventricular function were blinded to the assay results. Patients were grouped into those with normal ventricular function, systolic dysfunction only, diastolic dysfunction only, and both systolic and diastolic dysfunction. RESULTS: Mean (+/- SD) B-natriuretic peptide concentration was 416 +/- 413 pg/mL in the 253 patients diagnosed with abnormal left ventricular function, compared with 30 +/- 36 pg/mL in the 147 patients with normal left ventricular function. Patients with both systolic and diastolic dysfunction had the highest levels (675 +/- 423 pg/mL). The area under the receiver operating characteristic (ROC) curve for B-natriuretic peptide levels to detect any abnormal echocardiographic finding was 0.95 (91% confidence interval: 0.93 to 0.97). B-Natriuretic peptide levels were unable to differentiate systolic vs. diastolic dysfunction. In patients with symptoms of heart failure and normal systolic function, B-natriuretic peptide levels >57 pg/mL had a positive predictive value of 100% for diastolic abnormalities. CONCLUSIONS: A simple, rapid test for B-natriuretic peptide levels can reliably predict the presence or absence of left ventricular dysfunction on echocardiogram. For some patients, a normal level may preclude the need for echocardiography.     

Clinical significance of brain natriuretic peptide in patients with postmyocardial infarction

BACKGROUND: Risk stratification after acute myocardial infarction (AMI) includes the evaluation of left ventricular (LV) function. Natriuretic peptides, and particularly brain natriuretic peptide (BNP), emerged as a potential marker of ventricular function and prognosis after AMI. HYPOTHESIS: Brain natriuretic peptide levels are related to ventricular function, either systolic or isolated diastolic, and can give prognostic information in patients surviving AMI. METHODS: In all, 101 patients were enrolled. An echocardiographic (M-mode, two-dimensional, and pulsed Doppler) evaluation was performed and blood samples for BNP measurement were obtained. Clinical events were recorded during 12 months of follow-up. RESULTS: A negative correlation between BNP and LV ejection fraction was observed (r = -0.38; p < 0.001). The BNP levels were higher among patients with LV systolic dysfunction than in patients with isolated diastolic dysfunction (339.1 +/- 249.9 vs. 168.0 +/- 110.5 pg/ml, p = 0.001). The latter had higher levels of BNP than those with normal LV function (68.3 +/- 72.6 pg/ml, p < 0.001). The BNP accuracy to detect LV systolic dysfunction was good (area under the ROC curve [AUC] = 0.83) and increased when isolated diastolic dysfunction was also considered (AUC = 0.87). Brain natriuretic peptide had a very good accuracy in the prediction of death (AUC = 0.95) and the development of heart failure (AUC = 0.90). CONCLUSION: These results extend previous evidence relating BNP to systolic function after AMI. Furthermore, a relationship between BNP levels and diastolic function was found. Brain natriuretic peptide had a very good performance in detecting the occurrence of an adverse event. We conclude that BNP can detect high-risk patients and help select patients for more aggressive approaches.     

A prospective study in search of an optimal B-natriuretic peptide level to screen patients for cardiac dysfunction

Background

Although echocardiography is the gold standard test for suspected left ventricular dysfunction, its cost and availability limits its use as a routine screening tool. The high negative predictive value of B-natriuretic peptide (BNP) in dyspneic patients suggests its possible utility in screening patients prior to echocardiography. Determining an appropriate BNP level below which the need for echocardiography is precluded would be valuable. We hypothesized that a fixed plasma BNP level of 20 pg/mL and simple clinical parameters are an effective pre-echocardiographic screening tool for left ventricular dysfunction.

Methods

Two hundred and two patients at a Veterans Administration facility with symptoms suggestive of heart disease (male to female ratio 193:9, mean age 65 years) were screened prior to echocardiography. Patients with known cardiac dysfunction were excluded.

Results

BNP levels of ≥20 pg/mL were 79% sensitive and 44% specific in screening for any abnormality of ventricular function. The negative predictive value was 69%. When broken down into categories of dysfunction, the cutoff point of 20 pg/mL had a better negative predictive value for those with systolic dysfunction (96%) or systolic plus diastolic dysfunction (100%) if patients with diastolic dysfunction were excluded. The majority of patients with falsely low BNP levels (<20 pg/mL with positive echocardiographic findings) had mild diastolic dysfunction, with 3 patients exhibiting mild systolic dysfunction.

Conclusions

BNP may be a useful screening tool for left ventricular dysfunction in patients with history suggestive of heart disease and be used to assist in forming a pretest probability, which in turn could greatly assist in appropriateness of patient referral and in optimization of drug therapy.     

Effect of compensated renal dysfunction on approved heart failure markers: direct comparison of brain natriuretic peptide (BNP) and N-terminal pro-BNP

Brain natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) are markers of heart failure. Although renal dysfunction may increase plasma concentrations, the magnitude of this effect has not been assessed in a head-to-head comparison between the clinically approved tests. We assessed the effect of compensated renal dysfunction on BNP (Triage BNP; Biosite) and NT-proBNP (elecsys proBNP; Roche) in 469 randomly selected stable outpatients after myocardial infarction (MI; Monitoring Trends and Determinants in Cardiovascular Diseases [MONICA] register Augsburg) who were characterized with respect to renal function (glomerular filtration rate [GFR]; Cockroft method) and left ventricular (LV) ejection fraction (EF) and mass (2D echocardiography). BNP and NT-proBNP were elevated in MI patients with LV dysfunction (LVD; EF <35%) compared with MI patients with preserved EF ( >45%; BNP 139+/-27 pg/mL versus 75+/-6; NT-proBNP 816+/-237 pg/mL versus 243+/-20; both P <0.03). Among all MI patients, the prevalence of renal dysfunction (GFR <85 mL/min) was 24%. BNP and NT-proBNP were significantly elevated in MI patients with renal dysfunction (BNP 132+/-17 pg/mL versus 68+/-4 without renal dysfunction; NT-proBNP 535+/-80 pg/mL versus 232+/-19; both P <0.05), and both markers were correlated with GFR in univariate and multivariate analyses (all P <0.01). When binary cut-off values were stratified according to the absence or presence of renal dysfunction (BNP 75 pg/mL and 125 pg/mL, respectively; NT-proBNP 100 pg/mL and 350 pg/mL, respectively), the predictive power of both markers for the detection of LVD increased substantially. BNP and NT-proBNP are almost similarly influenced by mild-to-moderate renal dysfunction. Renal dysfunction is a potential cause of elevated marker concentrations in the absence of LVD, and cut-off concentrations should be stratified according to renal function.     

BNP as a marker of diastolic dysfunction in the general population: Importance of left ventricular hypertrophy

BNP is a marker of systolic left ventricular dysfunction (LVSD) and heart failure. To assess BNP for the detection of diastolic dysfunction in the general population, we examined 1678 subjects within an age- and sex-stratified survey (MONICA Augsburg). BNP was measured using a commercially available RIA (Shionogi). BNP increased in subjects with diastolic dysfunction (mean 20.3+/-4.7 pg/ml vs. control 9.6+/-0.5 pg/ml, p<0.001), but to a lesser extent than in subjects with LV hypertrophy (LVH, mean 37.3+/-49.1 pg/ml, p<0.001 vs. control) or LVSD (mean 76.2+/-23.2 pg/ml, p<0.001 vs. control). Individuals with sole diastolic abnormality displayed BNP concentrations at the control level (mean 9.7+/-1.7 pg/ml). In univariate analysis, age, BMI, systolic blood pressure, left atrial size, LV mass index, diastolic dysfunction and EF displayed a significant correlation with BNP (p<0.001). However, LV mass index displaced diastolic dysfunction as a significant predictor of BNP in multivariate analysis. Upon ROC analysis, sensitivity and specificity for the detection of diastolic dysfunction by BNP were only 61% and 55%, respectively. Nevertheless, a normal BNP test virtually excluded the presence of diastolic dysfunction and concomitant LVH (NPV 99.9%). Increased BNP concentrations in subjects with diastolic dysfunction are strongly related to LVH. Population-wide screening for diastolic dysfunction with BNP cannot be recommended although a normal BNP test usually excludes diastolic dysfunction and LV hypertrophy.     

Brain natriuretic peptide blood levels in the differential diagnosis of dyspnea.

STUDY OBJECTIVES: In dyspneic patients without left ventricular enlargement, it may be difficult to differentiate between obstructive lung disease and diastolic heart failure. Determination of plasma brain natriuretic peptide (BNP) levels, known to increase with ventricular stretch, may be of clinical relevance in this situation. We compared the discriminant power of BNP blood levels and of echocardiography in patients with either chronic obstructive lung disease or diastolic heart failure. PATIENTS: Twenty-six New York Heart Association class III dyspneic patients with normal left ventricular systolic function were enrolled: 17 patients with chronic obstructive lung disease and 9 patients with unequivocal diastolic heart failure. RESULTS: Echocardiographic data were unable to accurately differentiate between the two groups, whereas BNP levels were significantly and markedly higher in patients with diastolic heart failure when compared to those with obstructive lung disease (224 +/- 240 pg/mL vs 14 +/- 12 pg/mL, p < 0.0001). CONCLUSIONS: These preliminary results warrant a prospective, large-scale evaluation of the value of BNP assay for determining diastolic dysfunction, a common cause of dyspnea in elderly patients, and differentiating it from other diagnoses such as obstructive lung disease.     

B-type natriuretic peptide level in the diagnosis of asymptomatic diastolic dysfunction.

OBJECTIVE: Brain natriuretic peptide (BNP) reflects the left ventricular pressure and volume overload. It is known that it increases in systolic dysfunction proportionally with left ventricular pressure increase. The BNP levels are well correlated with NYHA classification and prognosis. Our aim was to evaluate the predictive value of BNP in patients with diastolic dysfunction but normal systolic dysfunction demonstrated by echocardiography. METHODS: Fifty patients (mean age: 48.5+/-6.75 years; 29 males, 21 females) were included in this cross-sectional, case-controlled study. Systolic dysfunction was the exclusion criterion. The following parameters were used to evaluate diastolic function: isovolumetric relaxation time, transmitral early to late filling flow velocities (E/A) ratio, deceleration time E, pulmonary vein Doppler findings and color mitral flow propagation velocity. Diastolic dysfunction was determined in 30 hypertensive patients (Group 1), whereas 20 patients who had normal diastolic flow patterns on echocardiography (Group 2). Blood samples were taken for serum BNP level measurements. RESULTS: The BNP levels were 12.0+/-4.97 pg/ml in individuals with normal filling pattern and 66.17+/-17.56 pg/ml in individuals with abnormal filling patterns (p<0.001). The accuracy of BNP in detection of diastolic dysfunction was assessed with receiver-operating characteristic (ROC) analysis. The area under the ROC curve for BNP test accuracy in detection any abnormal diastolic dysfunction was 0.969 (95% CI, 0.909 to 1.029; p<0.001). A BNP value of 37.0 pg/ml had sensitivity of 80%, specificity of 100%, a positive predictive value of 100%, a negative predictive value of 23% and accuracy of 88% in identifying asymptomatic prolonged relaxation pattern. We found a strong correlation between left ventricular mass index and plasma BNP levels (r=0.62, p<0.05). CONCLUSION: Estimation of BNP values could be accepted as a fast and reliable blood test in the diagnosis of asymptomatic diastolic dysfunction.     

Doppler echocardiography-derived index of myocardial performance (TEI index): comparison with brain natriuretic peptide levels in various heart disease.

Plasma brain natriuretic peptide (BNP) has diagnostic and prognostic value in heart failure. Cardiac dysfunction varies from systolic or diastolic dysfunction alone to the combination of both. In the present study, Doppler echocardiographic parameters, including the Doppler echocardiography-derived index (TEI index), were compared with plasma BNP levels in 74 patients with various heart diseases. Blood sampling was performed before an echocardiographic examination was conducted. The TEI index was defined as the summation of isovolumic contraction and relaxation time divided by ejection time. In patients with left ventricular (LV) systolic dysfunction (ejection fraction <50%), the TEI index and BNP were increased significantly compared with patients with normal LV systolic function (p<0.05). Patients with a TEI index > or =0.45 showed significantly increased BNP levels compared with patients with a TEI index <0.45, irrespective of LV systolic function (241.4+/-451.2 vs 65.9+/-81.8pg/ml; p<0.05). The TEI index was significantly higher in patients with a BNP > or =73pg/ml than in patients with BNP <73pg/ml (0.57+/-0.24 vs 0.46+/-0.17; p<0.05). Other echocardiographic parameters did not correlate significantly with levels of plasma BNP. Of the echocardiographic parameters, a simple Doppler index (TEI index) that combines systolic and diastolic function can detect LV dysfunction in patients with high levels of plasma BNP in various heart diseases.     

Diagnostic utility of brain-natriuretic peptide for left ventricular diastolic dysfunction in asymptomatic type 2 diabetic patients

AIM: Left ventricular (LV) diastolic dysfunction has been reported to be prevalent in diabetic subjects, but this recognition could often be missed. We evaluated prevalence of LV diastolic dysfunction and diagnostic utility of brain-natriuretic peptide (BNP) in asymptomatic patients with type 2 diabetes mellitus. RESEARCH DESIGN AND METHODS: Plasma BNP levels and LV geometry and diastolic filling indices, including the ratio of peak early transmitral Doppler flow (E) over flow propagation velocity (Vp) measured by colour M-mode Doppler echocardiography, were analysed in 98 consecutive asymptomatic patients with type 2 diabetes mellitus and 51 age-matched controls. RESULTS: The LV mass index and relative wall thickness were higher in diabetic groups than controls without any differences in LV systolic function. The frequency of diastolic dysfunction defined as E/Vp > or = 1.5 were 31% in diabetic groups and 15% in controls (chi(2) = 4.364, p = 0.037). By receiver-operating characteristic (ROC) curve analysis, a BNP cutoff value of 19.2 pg/ml in controls had a 53.1% positive predictive value (53.1%) and a high negative predictive value (94.4%) for E/Vp >/= 1.5, whereas a BNP cutoff value of 18.1 pg/ml in diabetic groups had a 61.8% positive and 97.3% negative predictive values. CONCLUSIONS: The frequency of E/Vp > or = 1.5 was higher in asymptomatic diabetic patients, suggesting that LV diastolic dysfunction was prevalent. The plasma concentration of BNP could be used to depict LV diastolic dysfunction in such population.     

Utility of B-natriuretic peptide in the evaluation of left ventricular diastolic function: comparison with tissue Doppler imaging recordings

Background

Although Doppler echocardiography provides assessment of abnormal left ventricular (LV) diastolic filling dynamics, its inherent limitations suggest the need for additional measures of diastolic dysfunction. The ratio of mitral velocity to early diastolic velocity of the mitral annulus (E/E′) derived from tissue Doppler imaging is associated with the mean LV end diastolic pressure (LVEDP). Because data suggest that B-natriuretic peptide (BNP) reflects ventricular pressure, we hypothesized that BNP levels correlate with indices of LV diastolic function by tissue Doppler imaging.

Methods and results

Doppler recordings of the mitral inflow and tissue Doppler imaging of the mitral annulus were obtained in 108 patients referred for echocardiography. BNP levels were measured by a rapid immunoassay and blinded to cardiologists making the assessment of LV function. BNP levels were higher when elevated E/E′ ratios derived from tissue Doppler imaging were identified. Patients identified with elevated LVEDP, defined as E/E′ >15 (n = 16), had the highest BNP levels (463 ± 80 pg/mL). Those with normal LVEDP, as predicted by E/E′ <8 (n = 36), had a mean BNP concentration of 97 ± 27 pg/mL. Those with E/E′ of 8 to 15 (n = 48) had a mean BNP level of 122 ± 24 pg/mL. The area under the receiver-operating curve for BNP to detect E/E′ >15 was 0.89 (95% CI, 0.82 to 0.96; P < .001). A BNP value of 173 pg/mL had a sensitivity of 88%, a specificity of 82%, and an accuracy of 83% for predicting E/E′ >15.

Conclusions

BNP levels correlate with the E/E′ ratios from tissue Doppler imaging (r = 0.48) and can reliably provide estimation of LV filling pressures. Although BNP levels do not correlate well with E/E′ ratios across the full spectrum of values, the combination of BNP levels along with E/E′ ratios from tissue Doppler imaging may be a better predictor of elevated LV filling pressures in patients with suspected diastolic dysfunction.     

Bedside tests of B-type natriuretic peptide in the diagnosis of left ventricular diastolic dysfunction in hypertensive patients

AIMS: To investigate the value of B-type natriuretic peptide (BNP) in diagnosing left ventricular diastolic dysfunction in patients with hypertension. METHODS: The left ventricular diastolic function and plasma BNP levels were assessed prospectively in 135 hypertensive patients. RESULTS: The plasma BNP in patients with (n=61) and without (n=74) diastolic dysfunction was 122+/-105 and 18+/-16 pg/ml, respectively (p<0.001). Increased BNP levels were associated with systolic blood pressure (p<0.05), left ventricular mass index (p<0.001), the E/A ratio of transmitral flow (p<0.01) and the isovolumic relaxation time (p<0.01). A receiver-operator characteristic curve showing the sensitivity and specificity of BNP against the echocardiography diagnosis of diastolic dysfunction revealed an area under the curve (accuracy) of 0.904 (p<0.01). Using a cut-off value of >40 pg/ml, the sensitivity and specificity of plasma BNP in diagnosing left ventricular diastolic dysfunction were 79% and 92%, respectively. CONCLUSIONS: The plasma BNP levels in patients with hypertension are closely related to left ventricular hypertrophy and filling impairment. Plasma BNP may be used to facilitate the diagnosis of left ventricular diastolic dysfunction.     

床边快速测定B型尿钠肽预测左心室收缩舒张功能

目的　评估床边快速测定B型尿钠肽 (BNP)预测左心室收缩舒张功能的价值。方法　对 2 16例患者行免疫荧光法床边快速测定BNP ,随后进行超声心动图检查 ,根据临床及超声心动图结果将患者分成左心室功能正常组 ,左心室舒张功能不全组和左心室收缩功能不全组。比较各组间BNP值及计算BNP对预测左心室收缩舒张功能不全的敏感性和特异性。结果　左心室功能正常组BNP值为 (31± 2 7) pg/ml,收缩功能不全组为 (5 18± 4 2 7)pg/ml,舒张功能不全组为 (12 4± 78) pg/ml。左心室收缩功能不全时BNP与左心室射血分数有较强的负相关 ,(R =- 0 .731,P <0 .0 0 1)。BNP预测左心室收缩功能不全的接受运行特征 (ROC)曲线下面积为 0 .96 ,以BNP≥ 10 0 pg/ml预测心力衰竭的敏感性为 90 % ,特异性为 91%。BNP预测左心室舒张功能不全的ROC曲线下面积为 0 .90 4。以BNP≥ 4 0pg/ml来预测左心室舒张功能不全的敏感性为 79% ,特异性为 92 %。 结论　床边测定BNP能快速可靠地预测左心室收缩舒张功能。     

The BNP assay does not identify mild left ventricular diastolic dysfunction in asymptomatic diabetic patients

Aims We examined the usefulness of BNP for screening for leftventricular (LV) diastolic dysfunction in a sample of type 2diabetic patients, without structural heart disorder, who havenever presented symptoms or signs of heart failure (HF). Methods and results Seventy-six consecutive patients admittedto the Outpatient Diabetes Clinic were studied. Blood sampleswere analyzed using the Triage BNP fluorescence immunoassay(Biosite Diagnostics, La Jolla, CA, USA). Echocardiography examinationswere performed, with no knowledge of the BNP value. A totalof 39 patients out of 76 (51%) were diagnosed with LV diastolicdysfunction and 23 (30%) with LV hypertrophy. Of the patientswith LV diastolic dysfunction, impaired relaxation and pseudonormalpattern accounted for 97 and 3% of the cases, respectively.BNP levels among subjects with LV diastolic dysfunction (26±22pg/ml,n=39) were not significantly different from patients with normalLV function (24±23pg/ml, n=37pg/ml; Mann–WhitneyU-test, Z=–0.4, n.s.). Conclusions Our data confirm alarmingly high prevalence of LVdiastolic dysfunction in asymptomatic individuals with diabetes.Identification of patients with preclinical diabetic cardiomyopathyshould be a research and clinical priority. BNP levels cannotbe used to detect mild LV diastolic dysfunction in this subsetof patients, which requires Doppler echocardiography to be detected.     

Plasma and pericardial fluid natriuretic peptide levels in postinfarction ventricular dysfunction

AIMS: In the present study we examined plasma and pericardial fluid ANP and BNP concentrations in postinfarction ventricular dysfunction. The association of peptide levels to left ventricular (LV) dysfunction and to the localization of the myocardial infarction (MI) was studied. METHODS AND RESULTS: Plasma and pericardial fluid samples were obtained from 37 patients undergoing coronary bypass surgery. According to the ECG and preceding coronary angiography, the patients were divided into three groups: previous anterior myocardial infarction (MI) (n=12), previous inferior/posterior MI (n=15) and no history of MI (n=10). When compared to the control group with no MI, the patients with anterior MI had elevated plasma ANP and BNP (134+/-13 vs. 81+/-15 pg/ml, P<0.01 and 95+/-10 pg/ml vs. 26+/-8 pg/ml, P<0.01, respectively) and pericardial fluid BNP (473+/-60 pg/ml vs. 57+/-8 pg/ml, P<0.001) levels. The plasma natriuretic peptide concentrations were not increased in the patients with inferior/posterior MI, but the pericardial fluid BNP concentrations were greater than in the patients with no history of MI (129+/-35 pg/ml vs. 57+/-8 pg/ml, P<0.05). Six of the 12 patients with previous anterior MI had LVEF> or =45%. Despite their normal LV systolic function, these patients had increased plasma and pericardial fluid BNP levels when compared to the group with no history of MI (68+/-18 pg/ml vs. 26+/-8 pg/ml, P<0.05 and 534+/-258 pg/ml vs. 57+/-8 pg/ml, P<0.01, respectively). CONCLUSIONS: Previous anterior myocardial infarction was associated with increased cardiac BNP production even if the LV systolic function was normal (LVEF> or =45%). The high pericardial fluid BNP concentrations in postinfarction patients suggest that the BNP synthesis and release are augmented in the ventricular myocardium independent from the LVEF.     

Wall stress modulates brain natriuretic peptide production in pressure overload cardiomyopathy

OBJECTIVES: We postulated that both diastolic and systolic load modulate B-type natriuretic peptide (BNP) production in human pressure overload hypertrophy/failure. BACKGROUND: In isolated myocytes, diastolic stretch induces BNP messenger ribonucleic acid expression. However, the mechanism of the BNP release in human hypertrophy remains controversial. METHODS: In 40 patients with symptomatic aortic stenosis (AS), left ventricular (LV) performance and systolic and diastolic wall stress were calculated from combined invasive and echocardiographic data. Plasma BNP was determined by the rapid point-of-care bedside analyzer (Biosite Triage, Biosite Diagnostics Inc., San Diego, California). RESULTS: A significant relationship was observed between plasma BNP and pulmonary capillary wedge pressure (p < 0.001), fractional shortening (p = 0.001), and aortic valve area (p = 0.006). Furthermore, a significant correlation was noted between BNP and LV mass index (p = 0.005) as well as between BNP and markers of diastolic load such as LV end-diastolic wall stress (p = 0.011), indexed LV end-diastolic volume (p < 0.001), and isovolumic relaxation time (p = 0.02). Preoperative BNP levels were elevated in patients with AS compared with patients without AS. Plasma BNP was higher in AS patients with impaired versus normal preload reserve (297 +/- 56 pg/ml vs. 168 +/- 44 pg/ml; p = 0.017) and in AS patients with clinical deterioration after valve replacement compared with those without (399 +/- 82 pg/ml vs. 124 +/- 41 pg/ml; p = 0.011). CONCLUSIONS: In patients with AS, BNP appears to be regulated not only by systolic but also by diastolic load. This supports the hypothesis that myocardial stretch modulates BNP production in human pressure overload hypertrophy/failure.     

Elevation of B-type natriuretic peptide levels in acute respiratory distress syndrome

BACKGROUND: B-type natriuretic peptide (BNP) has been proven to be a biochemical marker of severity of congestive heart failure. We are aware of only few papers reporting the association of BNP elevation and pulmonary hypertension (primary, thromboembolic, or as a consequence of chronic obstructive pulmonary disease). Less is known about BNP in patients with acute respiratory distress syndrome (ARDS). CASE DESCRIPTION AND RESULTS: We present the case of a previously healthy 27-year-old man with parapneumonic ARDS and an extraordinarily increased BNP level. The ventricular systolic ejection fraction assessed echocardiographically was normal with no evidence of left ventricular diastolic dysfunction. However, a peak BNP level of >1300 pg/mL (normal <100 pg/mL) was recorded. Repeated BNP values were obtained on nine separate days over a period of 3 weeks of mechanical ventilation. With the respiratory improvement following the inhalation of nitric oxide BNP levels decreased to 113 pg/mL. The possible pathophysiological mechanisms of BNP release are discussed. CONCLUSION: There is evidence for BNP elevation in the absence left ventricular dysfunction. This case is an example of impressively high BNP levels associated with ARDS, probably attributable to right ventricular overload due to increased pulmonary vascular resistance.     

The limited value of plasma B-type natriuretic peptide for screening for left ventricular hypertrophy among hypertensive patients

BACKGROUND: Several reports have suggested that plasma B-type natriuretic peptide (BNP) levels are elevated in hypertensive patients especially with left ventricular (LV) hypertrophy. However, few data have been available concerning the utility of plasma BNP measurement to identify LV hypertrophy in hypertensive patients in a general population screening context. METHODS: We measured plasma BNP concentrations in 1112 volunteers in a health screening program (mean age, 57 years). All subjects underwent electrocardiography, chest X-ray, and echocardiography. Among the sample, 284 subjects were designated as hypertensive because they were on antihypertensive drugs or showed elevated systemic blood pressure. By echocardiography, 36 of the hypertensive patients showed significant LV hypertrophy. RESULTS: There were no significant differences in age and sex between the LV hypertrophy and non-LV hypertrophy groups. Plasma BNP levels in the LV hypertrophy group were significantly higher than in the non-LV hypertrophy group (19.4 +/- 18.9 v 28.2 +/- 28.2 pg/mL; P <.05). However, the ability of plasma BNP levels to discriminate between LV hypertrophy and non-LV hypertrophy patients was not sufficient as the area under the receiver operating characteristic curve was 0.588 (95% CI: 0.528-0.646) with sensitivity of 50.0% and specificity of 69.0%. Positive and negative predictive values for detecting LV hypertrophy among hypertensive patients were 18.9% and 90.5%, respectively. This ability did not improve significantly when the screening was limited to patients with untreated LV hypertrophy or concentric LV hypertrophy. CONCLUSIONS: Plasma BNP testing in a mass screening setting is of limited use for the identification of LV hypertrophy patients among hypertensive patients with heterogeneous etiology.     

The role of NT-proBNP in the diagnostics of isolated diastolic dysfunction: correlation with echocardiographic and invasive measurements.

AIMS: Diastolic heart failure is a frequent entity but difficult to diagnose. N-terminal pro-B type natriuretic peptide (NT-proBNP) was therefore investigated as a possible non-invasive parameter to diagnose isolated diastolic dysfunction. METHODS AND RESULTS: Sixty-eight symptomatic patients with isolated diastolic dysfunction and preserved left ventricular ejection fraction (LVEF) (> or =50%) and 50 patients with regular left ventricular (LV) function were examined by conventional echocardiography, tissue Doppler imaging (TDI), and left and right heart catheterization. Plasma NT-proBNP levels were determined simultaneously. Median NT-proBNP plasma levels were elevated [189.54 pg/mL (86.16-308.27) vs. 51.89 pg/mL (29.94-69.71); P<0.001] and increased with greater severity of the diastolic dysfunction (R=0.67, P<0.001). According to the recevier operating characteristic analysis, LV end-diastolic pressure [area under the curve (AUC) 0.84] was the most specific parameter, which had a low sensitivity (61%), however. The reliability of NT-proBNP was similar to TDI indices (AUC 0.83 vs. 0.81) and improved when compared with conventional echocardiography (AUC 0.59-0.70). NT-proBNP levels had the best negative predictive value of all methods (94%) and correlated strongly with indices of LV filling pressure, as determined by invasive measurements. Multivariable linear regression analysis confirmed NT-proBNP as an independent predictor of diastolic dysfunction with an Odds ratio of 1.2 (1.1-1.4, CI 95%) for every unit increase of NT-proBNP. CONCLUSION: NT-proBNP can reliably detect the presence of isolated diastolic dysfunction in symptomatic patients and is an useful tool to rule out patients with reduced exercise tolerance of non-cardiac origin.     

Evaluation of brain natriuretic peptide as marker of left ventricular dysfunction and hypertrophy in the population

OBJECTIVE: To evaluate brain natriuretic peptide (BNP) as marker of left ventricular (LV) dysfunction and hypertrophy in a population-based sample of 610 middle-aged subjects (50-67 years) who were further characterized with respect to hemodynamic and anthropometric parameters and by echocardiography. RESULTS: Left ventricular (LV) systolic function, LV mass-index, age, gender, heart rate, and medication with beta adrenergic receptor blockers were significant and independently correlated with BNP (multivariate analysis, P < 0.05 each). As compared to subjects with normal LV function and mass-index (control), subjects with LV dysfunction (LV fractional shortening < 28%) or hypertrophy (LV mass-index > 110 g/m2 in women and > 134 g/m2 in men) were characterized by increased BNP. The increase in BNP associated with LV hypertrophy (n = 69, +101% versus control, P < 0.0001) was similar in magnitude to that associated with LV dysfunction (n = 39, +98% versus control, P < 0.03). These increases were markedly exceeded in subjects with severe LV dysfunction (n = 11, LV fractional shortening < 22%, BNP +197% versus control, P < 0.01), particularly in the presence of concomitant hypertrophy (n = 7, +227%, P < 0.01). The predictive values of BNP varied considerably with the degree of LV dysfunction and the presence or absence of concomitant LV hypertrophy. With 0.81, the highest area under the receiver operator characteristic curve was obtained for the detection of severe LV dysfunction and concomitant hypertrophy and sensitivity, specificity, positive and negative predictive value for this condition were 71, 86, 7 and 99.5%, respectively, for a cut-off of 34 pg/ml. CONCLUSIONS: The current study provides new insight into regulation and diagnostic value of BNP in middle-aged subjects and demonstrates important independent effects of LV function and mass upon BNP plasma concentrations. Although measurement of BNP cannot be recommended for the detection of marginally impaired LV function in the population, it may be helpful to suggest or exclude severe LV dysfunction with concomitant hypertrophy.     

Diastology: 2020-A practical guide

Left ventricular (LV) diastolic function can be most conveniently assessed by echocardiography which provides reliable assessments of LV structure and function. Most patients with structural heart disease have variable degrees of myocardial dysfunction. LV structural changes as pathologic hypertrophy and systolic functional abnormalities as depressed LV long-axis systolic function are associated with diastolic dysfunction. The recognition of structural abnormalities and abnormal LV long-axis function as indices of diastolic dysfunction is an important difference between 2016 and 2009 guidelines. In addition, there are other Doppler findings indicative of diastolic dysfunction and abnormally elevated LV filling pressures. In the absence of clinical, 2D echocardiographic, and specific Doppler indices of diastolic dysfunction, mitral annulus early diastolic velocity (e’), left atrium (LA) maximum volume index, peak velocity of tricuspid regurgitation jet by continuous-wave Doppler, and ratio of mitral inflow early diastolic velocity to e’ velocity can be used to draw inferences about LV diastolic function. In the presence of diastolic dysfunction, mean LA pressure and grade of diastolic dysfunction should be determined. When LA pressure at rest is normal, it is reasonable to proceed to diastolic stress testing in an attempt to identify patients with dyspnea due to heart failure. There are specific algorithms recommended in patients with atrial fibrillation, moderate or severe mitral annular calcification, and noncardiac pulmonary hypertension.