Natriuretic peptides in the management of aortic stenosis

Impact of diastolic dysfunction on long-term mortality and quality of life after transcatheter aortic valve replacement

BACKGROUND

There is conflicting data as to whether diastolic dysfunction (DD) affects the prognosis of patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR).

METHODS

Consecutive patients undergoing TAVR underwent assessment of DD with preoperative echocardiography and NT-pro BNP. Long-term survival was ascertained every 6 months by clinic visits or phone. DD was graded according to the new American Society of Echocardiography recommendations. Health status was assessed at baseline and 30 days post-procedure using the KCCQ-12 questionnaire. Long-term survival was displayed using Kaplan-Meier curves according to NT-pro BNP levels and DD grades.

RESULTS

We included 222 patients, mean age 78 (±8) years, median STS score 4 (interquartile range = 3-7), median follow-up time 385 days (IQR = 180-640). DD was absent in 25, Grade I in 13, Grade II in 74, Grade III in 24, and indeterminate in 86 patients. Advanced (Grades II-III) DD was associated with higher pre-procedural NT-pro BNP levels (p < .001), worse quality of life (p < .001) but similar surgical risk (p = .43). Advanced and indeterminate DD were associated with increased long-term mortality (25-28% vs. 5%, p = .02) and elevated NT-pro BNP levels (26.4% vs. 9.8%, p = .05). Improvements in quality of life measures were seen in all DD groups (median change in KCCQ score no or Grade I DD:14 [3-21] vs. Grades II-III DD: 15 [16-26; p = .37]).

CONCLUSION

Preoperative NT-pro BNP levels and echocardiographic indices of indeterminate or advanced DD are associated with increased long-term mortality after TAVR but similar improvements in quality of life.

Rise and fall of NT-proBNP in aortic valve intervention

Objectives

To describe the dynamics of N-terminal pro-B-type natriuretic peptide (NT-proBNP) from preoperative evaluation to 6-month follow-up in patients undergoing aortic valve intervention, and to evaluate NT-proBNP with regard to 1-year mortality.

Methods

At preoperative evaluation, we prospectively included 462 patients accepted for aortic valve intervention. The median time to surgical aortic valve replacement (SAVR; n=336) or transcatheter aortic valve implantation (TAVI; n=126) was 4 months. NT-proBNP was measured at enrolment for preoperative evaluation, on the day of surgery, postoperatively on day 1, day 3 and at the 6-month follow-up. Subgroups of patients undergoing SAVR with aortic regurgitation and aortic stenosis with and without coronary artery bypass were also analysed.

Results

NT-proBNP remained stable in all subgroups during the preoperative waiting period, but displayed a substantial transient early postoperative increase with a peak on day 3 except in the TAVI group, which peaked on day 1. At the 6-month follow-up, NT-proBNP had decreased to or below the preoperative level in all groups. In the SAVR group, NT-proBNP preoperatively and on postoperative days 1 and 3 revealed significant discriminatory power with regard to 1-year mortality (area under the curve (AUC)=0.79, P=0.0001; AUC=0.71, P=0.03; and AUC=0.79, P=0.002, respectively). This was not found in the TAVI group, which had higher levels of NT-proBNP both preoperatively and at the 6-month follow-up compared with the SAVR group.

Conclusions

The dynamic profile of NT-proBNP differed between patients undergoing TAVI and SAVR. NT-proBNP in the perioperative course was associated with increased risk of 1-year mortality in SAVR but not in TAVI.

Depressed Systemic Arterial Compliance is Associated with the Severity of Heart Failure Symptoms in Moderate-to-Severe Aortic Stenosis: a Cross-Sectional Retrospective Study

BACKGROUND

Patients with aortic stenosis (AS) may develop heart failure even in the absence of severe valve stenosis. Our aim was to assess the contribution of systemic arterial properties and the global left ventricular afterload to graded heart failure symptoms in AS.

METHODS

We retrospectively reviewed medical records of 157 consecutive subjects (mean age, 71±10 years; 79 women and 78 men) hospitalized owing to moderate-to-severe degenerative AS. Exclusion criteria included more than mild aortic insufficiency or disease of another valve, atrial fibrillation, coronary artery disease, severe respiratory disease or anemia. Heart failure symptoms were graded by NYHA class at admission. Systemic arterial compliance (SAC) and valvulo-arterial impedance (Zva) were derived from routine echocardiography and blood pressure.

RESULTS

Sixty-one patients were asymptomatic, 49 presented mild (NYHA II) and 47 moderate-to-severe (NYHA III-IV) heart failure symptoms. Mild symptoms were associated with lower SAC and transvalvular gradients, while more severe exercise intolerance coincided with older age, lower systolic blood pressure, smaller aortic valve area and depressed ejection fraction. By multiple ordinal logistic regression, the severity of heart failure symptoms was related to older age, depressed ejection fraction and lower SAC. Each decrease in SAC by 0.1 ml/m² per mmHg was associated with an increased adjusted odds ratio (OR) of a patient being in one higher category of heart failure symptoms graded as no symptoms, mild exercise intolerance and advanced exercise intolerance (OR: 1.16 [95% CI, 1.01-1.35], P=0.045).

CONCLUSIONS

Depressed SAC may enhance exercise intolerance irrespective of stenosis severity or left ventricular systolic function in moderate-to-severe AS. This finding supports the importance of non-valvular factors for symptomatic status in AS.

High Thoracic Epidural in Cardiac Anesthesia

High thoracic epidural analgesia (HTEA) offers a distinctive opportunity to enhance postoperative recovery for the thoracic surgery patient. In the modern hospital setting with day of admission surgery, the logistics of insertion of the epidural catheter has become increasingly difficult. The greatest limitation to its use might be the believed increased risk of epidural hematoma associated with anticoagulation during cardiopulmonary bypass. The aim of this review is to give an overview of complications and effect on outcomes with focus on cardiac performance and postoperative glycemic control and kidney function. Patients with epidurals may have improved postoperative pulmonary function and shorter ventilation time, while impact on length of stay in the intensive care unit and hospital is not as evident. HTEA is effective in pain management, attenuates perioperative stress and seems to improve postoperative blood glucose control. Whether HTEA improves recovery and facilitates fast-track is still to be confirmed. With regard to serious postoperative complications, there is evidence of reduction in supraventricular arrhythmias and lower frequency of postoperative acute kidney injury and dialysis. There are some indications of lower short term mortality and frequency of postoperative myocardial infarctions, but only as a combined outcome. The present short-term mortality of 1% to 2% should be compared with the most pessimistic frequency of epidural hematoma being 1 in 4600 patients.

Long-term prognostic value and serial changes of plasma N-terminal prohormone B-type natriuretic peptide in patients undergoing transcatheter aortic valve implantation

Little is known about the usefulness of evaluating cardiac neurohormones in patients undergoing transcatheter aortic valve implantation (TAVI). The objectives of this study were to evaluate the baseline values and serial changes of N-terminal prohormone B-type natriuretic peptide (NT-proBNP) after TAVI, its related factors, and prognostic value. A total of 333 consecutive patients were included, and baseline, procedural, and follow-up (median 20 months, interquartile range 9 to 36) data were prospectively collected. Systematic NT-proBNP measurements were performed at baseline, hospital discharge, 1, 6, and 12 months, and yearly thereafter. Baseline NT-proBNP values were elevated in 86% of the patients (median 1,692 pg/ml); lower left ventricular ejection fraction and stroke volume index, greater left ventricular mass, and renal dysfunction were associated with greater baseline values (p <0.01 for all). Higher NT-proBNP levels were independently associated with increased long-term overall and cardiovascular mortalities (p <0.001 for both), with a baseline cut-off level of ∼2,000 pg/ml best predicting worse outcomes (p <0.001). At 6- to 12-month follow-up, NT-proBNP levels had decreased (p <0.001) by 23% and remained stable up to 4-year follow-up. In 39% of the patients, however, there was a lack of NT-proBNP improvement, mainly related to preprocedural chronic atrial fibrillation, lower mean transaortic gradient, and moderate-to-severe mitral regurgitation (p <0.01 for all). In conclusion, most patients undergoing TAVI presented high NT-proBNP levels, and a lack of improvement was observed in >1/3 of the patients after TAVI. Also, higher NT-proBNP levels predicted greater overall and cardiac mortalities at a median follow-up of 2 years. These findings support the implementation of NT-proBNP measurements for the clinical decision-making process and follow-up of patients undergoing TAVI.

Elevated intraoperative expression of ventricular myosin light chain predicts heart failure after valve replacement surgery

BACKGROUND

It can be difficult to predict which patients will survive and recover cardiac function after valve replacement surgery. We hypothesized that the expression levels of ventricular myosin light chain (MLCv) might reflect the severity of disease or the extent of irreversible myocardial damage and might be useful for predicting the postoperative course. Thus, the aim of this study was to explore the relationship between MLCv expression in specimens obtained during valve replacement surgery and the postoperative New York Heart Association (NYHA) class.

METHODS

The levels of expression of the regulatory MLCv (MLC-2v) and MLC-1v in papillary muscle specimens from 80 patients who underwent valve replacement surgery for rheumatic valvular disease were evaluated by Western blot analysis.

RESULTS

The patients were similar with regard to the intraoperative expression of MLC-1v, regardless of postoperative NYHA class. The preoperative NYHA class, the end-systolic left ventricular internal dimension, and the intraoperative expression of MLC-2v emerged as independent risks factors for a NYHA class status of III/IV at 6 months after surgery, with an area under the receiver operating characteristic curve of 0.862.

CONCLUSION

The intraoperative level of MLC-2v expression was predictive of the patients' NYHA class after valve replacement surgery. This result suggests that future studies evaluating the use of preoperative specimens (such as biopsy or peripheral blood samples) for measurement of MLC-2v levels could lead to a valuable preoperative tool for the assessment of candidates for valve replacement.

Clinical relevance of time course of BNP levels in neonates with congenital heart diseases

INTRODUCTION

The aim of this study is to better characterize the time courses of BNP levels throughout the first days of life in larger populations of neonate and infant with or without congenital heart diseases (CHD) in order to increase the diagnostic accuracy of BNP assay in pediatric patients with CHD.

MATERIALS AND METHODS

BNP was measured by an automated platform (Triage BNP reagents, ACCESS Immunoassay Systems, Beckman Coulter, Inc., Fullerton, CA 92835) in 218 neonates and infants with different CHD; 222 healthy children, matched for age, served as controls.

RESULTS

BNP values were significantly higher (P<0.001) in the whole group of CHD patients (median 1029.8 ng/L, range 25-20,152 ng/L) than in controls (median 149.5 ng/L, range 9-866 ng/L). A different trend between BNP values and age was observed in healthy subjects and CHD patients. After an initial increase within the first 4 days of life, BNP values in CHD patients tend to stabilize to high values in the following days. On the contrary, in control subjects a peak of BNP levels was observed in the second or third day, followed by a progressive decrease. Therefore, the diagnostic accuracy of BNP assay, calculated in the samples collected in the first four days of life (AUC of ROC analysis 0.86, 95% CI 0.83-0.90) was significantly lower (P<0.0001) compared to samples collected from 5 days to 30 days of life (AUC 0.97, 95% CI 0.95-0.99). Optimal cut-off values for BNP assay, as calculated by ROC analysis, were also age-dependent (cutoff for the first 4 days of life: 363.5 ng/L; cutoff values from 5 to 30 days of life: 109.5 ng/L).

CONCLUSIONS

Our study demonstrates that differences in time-courses of BNP values between newborns with and without CHD throughout the first days of life clearly affect the diagnostic accuracy of BNP assay. Indeed, the diagnostic accuracy of BNP assay in discriminating between healthy newborns and CHD patients progressively increases after the 4th day of life. As a result, also cutoff values of BNP assay greatly change throughout the first days of life. However, decision values of BNP assay are strongly method-dependent, consequently clinicians should give great care to compare results obtained by different laboratories, especially when different methods are used.

Postoperative increase in B-type natriuretic peptide levels predicts adverse outcome after cardiac surgery

OBJECTIVE

To evaluate the prognostic implication of changes in postoperative B-type natriuretic peptide (BNP) concentrations in patients undergoing cardiopulmonary bypass for cardiac surgery.

DESIGN

A retrospective analysis of prospectively collected clinical data.

SETTING

Cardiothoracic surgery and an intensive care unit (ICU) in a university hospital.

PARTICIPANTS

The present study included a total of 407 consecutive patients undergoing cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

BNP concentrations were measured on admittance to the ICU (D0) and at day 1 after surgery. Patients were divided into quintiles according to their BNP level on admittance to the ICU. The predictive value of absolute changes in BNP levels during the first 24 hours postoperatively was analyzed with Kaplan-Meier estimates of survival and Cox multivariate proportional analysis. Prognostic factors for impaired midterm survival included elevation of the BNP level (HR, 7.3/ log10(x); 95% confidence interval, 1.8-29, p = 0.005). The BNP levels of patients undergoing isolated valve surgery or valve and concomitant CABG surgery were significantly higher (p = 0.012 and p = 0.032, respectively) than those undergoing isolated coronary artery bypass graft surgery. Patients in higher quintiles required ventilation for a longer time (p < 0.001), and prolonged inotropic support (p < 0.001). The mean plasma BNP concentration of 172 pg/mL (median, 64; interquartile range, 172) on arrival at the ICU had a sensitivity of 75% and a specificity of 74% for predicting 1-year mortality.

CONCLUSIONS

Elevated BNP levels on admittance to the ICU and postoperatively increasing BNP levels are associated with adverse postoperative outcome and are predictive of impaired late survival. Sequential postoperative BNP monitoring facilitates the early identification of patients at an increased risk of heart failure and may be used as an adjunct for clinical decision making and optimized patient management.

Validation of plasma biomarkers in degenerative calcific aortic stenosis

BACKGROUND

Calcific aortic stenosis (CAS) is the most common acquired valvular disorder in industrialized countries. This study investigates the correlation of different known biomarkers for CAS as a first step towards the development of a panel of biomarkers that can be used in prognostic staging.

METHODS

Venous blood samples were obtained from both patients with CAS scheduled for surgery and healthy individuals. Plasma levels of fetuin-A, NT-proBNP, BNP, homocysteine and osteopontin were measured by enzyme-linked immunosorbent assay (ELISA). CAS was measured by echocardiography and was defined as an aortic valve area of less than 2.0 cm(2). Non-paired t-tests were used for comparison.

RESULTS

CAS was present in 33 subjects (mean age 75.9 y) and absent in 11 subjects (mean age 55.36 y). Individuals with CAS exhibited higher plasma levels of NT-proBNP (1.33 versus 0.73 pmol/mL, P < 0.05), BNP fragment (1.47 versus 0.34 ng/mL P < 0.05), and osteopontin (60.79 versus 25.42 ng/mL P < 0.05) compared with controls. Fetuin-A levels were lower in individuals with CAS than in healthy controls (0.25 versus 0.34g/L, P < 0.05). Asymmetric dimethylarginine (ADMA) were lower (1.08 versus 1.1 micromol/L, P > 0.05) while homocysteine levels (20.34 +/- 2.14 versus 19.23 +/- 4.19 P > 0.05) were higher in the CAS patients.

CONCLUSION

This study demonstrates a direct correlation of NT-pro-BNP, BNP, and osteopontin and the presence of CAS, while fetuin A showed an inverse correlation. Plasma ADMA and homocysteine levels were comparable in the CAS patients and healthy individuals. This is the first study in which several biomarkers previously studied independently in patients with CAS have been investigated simultaneously in the same study population.