Postoperative B-type Natriuretic Peptide Research Articles

Acute B-type natriuretic peptide response and early postoperative right ventricular physiology following tetralogy of Fallot's repair

B-type natriuretic peptide (BNP) response early after a tetralogy of Fallot's repair remains unclear. BNP was measured pre- and post-operatively (immediately, day 1) in 18 children undergoing corrective repair with concurrent echocardiography (pre-, post-op day 1) to assess right ventricular (RV) systolic dysfunction, restrictive physiology, wall motion and pulmonary regurgitation (PR). In the first 24 h postoperatively, BNP rose acutely in all patients (mean 34.9 vs 144.4 vs 716.9 pg/ml at pre-op, days 0 and 1; P < 0.001). Immediate postoperative BNP correlated with preoperative haematocrit (rho = 0.52, P = 0.03) and inversely with preoperative oxygen saturation (rho = -0.63, P = 0.007). All patients showed reduced RV systolic function and abnormal wall motion with at least moderate PR in six patients (33.3%) and restrictive physiology in four (24%). Subsequent BNP expression (post-op day 1) correlated with a low RV fractional area change (rho = -0.51, P = 0.04), high oxygen extraction ratio (rho = 0.56, P = 0.02) and high central venous pressure (rho = 0.79, P < 0.001). The LV function and wall motion remained preserved in all patients. The mechanism of BNP expression is likely to be multi-factorial in the presence of a complex postoperative RV physiology in tetralogy of Fallot. An acute BNP response in the early postoperative period reflects an important physiological role and may be used as an adjunct biomarker to assess the RV function.

Prognostic Power of Pre- and Postoperative B-Type Natriuretic Peptide Levels in Patients Undergoing Abdominal Aortic Surgery

The first aim of the present study was to evaluate the pre- and postoperative B-type natriuretic peptide (BNP) levels in patients undergoing surgery for repair of an infrarenal abdominal aortic aneurysm (AAA) and analyze their power as a predictor of in-hospital cardiac events. The second aim was to evaluate the association among pre- and postoperative BNP levels, postoperative patient complications, and length of hospital stay. Prospective observational study. A university hospital. Forty-five patients undergoing elective surgery for an abdominal aortic aneurysm. The plasma BNP level was assessed just before surgery and then on postoperative day 1. Cardiac troponin I levels were measured postoperatively on arrival to the intensive care unit (time 0) and then 12, 48, and 72 hours later. The preoperative BNP concentration in patients who developed an acute myocardial infarction was 209 (IQR 84-346) pg/mL compared with 74 (IQR 28-142) pg/mL in those who did not. The difference between groups was statistically significant (p = 0.04). The Spearman correlation showed that postoperative BNP levels correlated significantly with preoperative BNP levels (r = 0.73, p = 0.0001), length of hospital stay (r = 0.35, p = 0.04), and troponin I concentration at 0 hour (r = 0.42, p = 0.02), 12 hours (r = 0.51, p = 0.0052), and 48 hours (r = 0.40, p = 0.033). In contrast, preoperative BNP levels correlated with troponin I at only 12 hours (r = 0.34, p = 0.02). Postoperative BNP levels were influenced significantly by transfusions (p = 0.035) and cross-clamping times (p = 0.038). The present results confirm the high negative predictive value of preoperative BNP levels; and postoperative BNP levels showed a better correlation with postoperative troponin levels, blood transfusion, and postoperative cardiac events.

Postoperative B-Type Natriuretic Peptide Levels Associated With Prolonged Hospitalization in Hypertensive Patients After Non-Cardiac Surgery

Background and ObjectivesB-type natriuretic peptide (BNP) is an important marker for the diagnosis of heart failure and is useful towards predicting morbidity and mortality after non-cardiac surgery. Nevertheless, information on the relationship between postoperative BNP levels and perioperative prognosis after non-cardiac surgery is scarce. The purpose of the study was to assess whether postoperative BNP levels could be used as a predictor of prolonged hospitalization in elderly hypertensive patients after non-cardiac surgery.Subjects and MethodsNinety-seven (97) patients, aged 55 years or older (mean age: 73.12±10.05 years, M : F=24 : 73) were enrolled in a prospective study from May 2005 through August 2010. All patients underwent total knee or hip replacement. Postoperative BNP and other diagnostic data were recorded within 24 hours of surgery. Patients that required a prolonged hospital stay due to operative causes, such as wound infection and re-operation, were excluded.ResultsThe length of hospital stay was significantly correlated with postoperative BNP levels (p=0.031). Receiver operating characteristic curves demonstrated postoperative BNP levels as predictors of hospital stay ≥30 days with areas under the curve of 0.774 (95% confidence interval: 0.679-0.87, p<0.0001). A BNP cut-off value above 217.5 pg/mL had a sensitivity of 80.6% and a specificity of 66.7% for predicting postoperative hospital stays of 30 days or more.ConclusionPostoperative BNP levels may predict the length of hospital stays after non-cardiac surgery in hypertensive patients. Elevated BNP levels were associated with prolonged hospitalization after elective orthopedic surgery.

Risk Stratification by Cardiac Biomarkers following Emergency Gastrointestinal Surgery

Perioperative cardiac complications are a major cause of death following emergency gastrointestinal surgery. Early diagnosis of subclinical myocardial injury and infarction may be improved by screening with cardiac biomarkers. The aim of this study was to assess the predictive value of troponin I (TnI) and B-type natriuretic peptide (BNP) in the early postoperative period after emergency gastrointestinal surgery. We prospectively recruited 48 patients undergoing major emergency surgery for gastrointestinal or colorectal pathology in a single district general hospital. The primary endpoint was mortality at 90 days following surgery. Overall survival was 81.3% (39/48), with 9 postoperative deaths. Elevated TnI (≥0.03 ng ) was the best predictor of mortality, associated with an odds ratio of death by 90 days of 14.3 (95% CI 1.50–337, ). A postoperative BNP concentration &gt;408.5 pg was associated with an odds ratio of death by 90 days of 13.6 (95% CI 2.03–106, ). A single measurement of postoperative BNP and TnI is a powerful predictor of short- to medium-term mortality in patients after emergency gastrointestinal surgery. Further work is required to demonstrate that cardiac biomarkers have independent predictive power and that patient outcomes can be improved.

Increased Peak Postoperative B-Type Natriuretic Peptide Predicts Decreased Longer-Term Physical Function After Primary Coronary Artery Bypass Graft Surgery

Background: Increased peak postoperative B-type natriuretic peptide (BNP) is associated with increased major adverse cardiovascular events and all-cause mortality after coronary artery bypass graft (CABG) surgery. Whether increased postoperative BNP predicts worse postdischarge physical function (PF) is unknown. We hypothesized that peak postoperative BNP associates with PF assessed up to 2 yr after CABG surgery, even after adjusting for clinical risk factors. including preoperative PF. Methods: This two-institution prospective cohort study included patients undergoing primary CABG surgery with cardiopulmonary bypass. Short Form-36 questionnaires were administered to subjects preoperatively and 6 months, 1 yr, and 2 yr postoperatively. Short Form-36 PF domain scores were calculated using the Short Form-36 norm-based scoring algorithm. Plasma BNP concentrations measured preoperatively and on postoperative days 1―5 were log 10 transformed before analysis. To determine whether peak postoperative BNP independently predicts PF scores 6 months through 2 yr after CABG surgery, multivariable longitudinal regression analysis of the postoperative PF scores was performed, adjusting for important clinical risk factors. Results: A total of 845 subjects (mean ± SD age, 65 ± 10 yr) were analyzed. Peak postoperative BNP was significantly associated with postoperative PF (effect estimate for log 10 peak BNP, -7.66 PF score points [95% CI, -9.68 to -5.64]; P = <0.0001). After multivariable adjustments, peak postoperative BNP remained independently associated with postoperative PF (effect estimate for log 10 peak BNP, ―3.06 PF score points [95% CI, -5.15 to -0.97]; P = 0.004). Conclusions: Increased peak postoperative BNP independently associates with worse longer-term PF after primary CABG surgery. Future studies are needed to determine whether medical management targeted toward reducing increased postoperative BNP can improve PF after CABG surgery.

The Prognostic Value of B-Type Natriuretic Peptide After Cardiac Surgery: A Comparative Study Between Coronary Artery Bypass Graft Surgery and Aortic Valve Replacement

The influence of the cardiac surgical procedure on B-type natriuretic peptide (BNP) for the identification of high-risk patients has not been evaluated. This study aimed to compare the prognostic utility of pre- and postoperative BNP in predicting adverse long-term outcome after coronary artery bypass graft (CABG) surgery and aortic valve replacement (AVR). A retrospective study. A university teaching hospital. One hundred eighty-nine patients. Preoperative, early postoperative (24 hours), and late postoperative (day 5) BNP levels were measured. Major adverse cardiac events (MACEs) within 12 months after surgery were chosen as study endpoints. The predictive abilities of BNP measurements were compared using receiver operating characteristic (ROC) curves. Patients were stratified by CABG surgery (n = 100) and AVR (n = 89). Thirty-four (18%) patients experienced 44 MACEs over the study period. Preoperative BNP values were significantly different between groups. Postoperative BNP gradually increased by 431% on day 5 after CABG surgery and by 100% after AVR (both p < 0.001 v preoperative values). Pre- and early postoperative BNP values were accurate in predicting MACEs after AVR (areas under the ROC curves: 0.78 [95% confidence interval, 0.66-0.90] and 0.76 [95% confidence interval, 0.62-0.89], respectively) and inaccurate after CABG surgery (0.54 [95% confidence interval, 0.38-0.70] and 0.54 [95% confidence interval, 0.36-0.73], respectively). The late postoperative BNP value was of limited value. BNP measurements should take into account the type of cardiac surgery. Whatever the time of measurement, BNP accurately predicts long-term adverse outcome in valve surgery patients. A late postoperative BNP measurement is useless after cardiac surgery.

No change in B-type natriuretic peptide levels assessed in the intermediate postoperative period in patients with severe mitral regurgitation after mitral valve surgery

The impact of mitral valve (MV) surgery on levels of B-type natriuretic peptide (BNP) postoperatively has not been clearly evaluated. The aim of this study was to assess whether BNP levels decrease three to six months after MV surgery in patients with severe mitral regurgitation (MR). We prospectively enrolled patients who were referred for MV surgery with severe MR. BNP levels were measured prior to and after surgery. The mean age was 61.3 ± 13.6 years; 75% were male (n = 52). There was no difference between the mean preoperative and postoperative BNP (242.9 ± 280.3 pg/ml, 290.8 ± 549.8 pg/ml, P = 0.45) obtained at a mean of 138.7 ± 33.5 days with the bias-corrected bootstrapped 95% confidence intervals, 117.6-321.8 pg/ml and 185.4-483.8 pg/ml, respectively. Postoperative BNP tended to increase as the amount of MR increased (no MR: 212.7 ± 197.5 pg/ml, 1+MR: 592.9 ± 1174.9 pg/ml, 2+MR: 133.6 ± 121.6 pg/ml, 3+MR: 547.7 ± 332.0 pg/ml; P < 0.0001). A mild inverse correlation was noted with postoperative BNP and postoperative ejection fraction (r = -0.2596). A decrease in the ejection fraction was noted after surgery (51.7 ± 11.1%, 56.3 ± 9.6%; P = 0.03). Our findings contradict an intuitive thought that BNP levels should decrease after MV surgery for MR.

Increased Peak Postoperative B-type Natriuretic Peptide Predicts Decreased Longer-term Physical Function after Primary Coronary Artery Bypass Graft Surgery

Increased peak postoperative B-type natriuretic peptide (BNP) is associated with increased major adverse cardiovascular events and all-cause mortality after coronary artery bypass graft (CABG) surgery. Whether increased postoperative BNP predicts worse postdischarge physical function (PF) is unknown. We hypothesized that peak postoperative BNP associates with PF assessed up to 2 yr after CABG surgery, even after adjusting for clinical risk factors. including preoperative PF. This two-institution prospective cohort study included patients undergoing primary CABG surgery with cardiopulmonary bypass. Short Form-36 questionnaires were administered to subjects preoperatively and 6 months, 1 yr, and 2 yr postoperatively. Short Form-36 PF domain scores were calculated using the Short Form-36 norm-based scoring algorithm. Plasma BNP concentrations measured preoperatively and on postoperative days 1-5 were log(10) transformed before analysis. To determine whether peak postoperative BNP independently predicts PF scores 6 months through 2 yr after CABG surgery, multivariable longitudinal regression analysis of the postoperative PF scores was performed, adjusting for important clinical risk factors. A total of 845 subjects (mean ± SD age, 65 ± 10 yr) were analyzed. Peak postoperative BNP was significantly associated with postoperative PF (effect estimate for log(10) peak BNP, -7.66 PF score points [95% CI, -9.68 to -5.64]; P = <0.0001). After multivariable adjustments, peak postoperative BNP remained independently associated with postoperative PF (effect estimate for log(10) peak BNP, -3.06 PF score points [95% CI, -5.15 to -0.97]; P = 0.004). Increased peak postoperative BNP independently associates with worse longer-term PF after primary CABG surgery. Future studies are needed to determine whether medical management targeted toward reducing increased postoperative BNP can improve PF after CABG surgery.

No change in B-type natriuretic peptide levels assessed in the late postoperative period in patients with severe mitral regurgitation after mitral valve surgery

The impact of mitral valve (MV) surgery on levels of B-type natriuretic peptide (BNP) postoperatively has not been clearly evaluated. The aim of this study was to assess whether BNP levels decrease three to six months after MV surgery in patients with severe mitral regurgitation (MR). We prospectively enrolled patients who were referred for MV surgery with severe MR. BNP levels were measured prior to and after surgery. The mean age was 61.3 ± 13.6 years; 75% were male (n = 52). There was no difference between the mean preoperative and postoperative BNP (242.9 ± 280.3 pg/ml, 290.8 ± 549.8 pg/ml, P = 0.45) obtained at a mean of 138.7 ± 33.5 days with the bias-corrected bootstrapped 95% confidence intervals, 117.6-321.8 pg/ml and 185.4-483.8 pg/ml, respectively. Postoperative BNP tended to increase as the amount of MR increased (no MR: 212.7 ± 197.5 pg/ml, 1+MR: 592.9 ± 1174.9 pg/ml, 2+MR: 133.6 ± 121.6 pg/ml, 3+MR: 547.7 ± 332.0 pg/ml; P < 0.0001). A mild inverse correlation was noted with postoperative BNP and postoperative ejection fraction (r = -0.2596). A decrease in the ejection fraction was noted after surgery (51.7 ± 11.1%, 56.3 ± 9.6%; P = 0.03). Our findings contradict an intuitive thought that BNP levels should decrease after MV surgery for MR.

Immediately Postoperative B-Type Natriuretic Peptide and Its Predictive Value

Major vascular surgery involves a high risk of major cardiovascular morbidity and mortality. A method of predicting perioperative myocardial events is required. Preoperative B-type natriuretic peptide (BNP) has been evaluated for this purpose. The aims of this study were to determine the postoperative course of BNP levels and correlate these levels with the outcome. The present study included 45 patients undergoing major vascular surgery. These patients further underwent serial venous blood sampling for troponin-T and BNP and serial electrocardiograms, pre- and postoperatively (immediately postoperatively and at days 1 through 4). Of the 45 patients, seven suffered myocardial damage, as defined by troponin-T. An immediate postoperative BNP (cutoff, 171 pg/mL) was better able to predict cardiac damage (p = 0.027) than BNP levels preoperatively (cutoff, 281 pg/mL, p = 0.042) and on day 1 postoperatively (cutoff, 182 pg/mL, p = 0.032). Only the preoperative BNP levels showed an effect on survival. Patients with a preoperative BNP >281 pg/mL had a mean survival of 12.7 months, as compared with 17.6 months for patients with a BNP <281 pg/mL, p = 0.044. Preoperative BNP is an accurate determinant of postoperative cardiac morbidity and all cause survival, with BNP in the immediate postoperative period being an even more accurate predictor of cardiac events. An immediate postoperative BNP might help risk stratify patients for the next 72 hours in the perioperative period (and maybe longer).

B-Type Natriuretic Peptide Levels and Continuous-Flow Left Ventricular Assist Devices

We postulated that postoperative B-type natriuretic peptide (BNP) levels would be reflective of the degree of hemodynamic support rendered by various pump speeds settings (RPM) of continuous-flow left ventricular assist devices (LVADs). Twenty LVAD patients were evaluated prospectively (Jarvik 2000: n = 9, HeartMate II: n = 11). The mean age was 57.7 ± 14.9 years, and 14 were male. B-type natriuretic peptide levels were drawn while the patients were supported on LVADs at variable RPM settings. The RPM settings were correlated with the changes in BNP levels. Eleven patients underwent LVAD implantation for a lifelong support while the rest were as a bridge therapy to transplantation. Four patients required LVAD change out for various causes of pump failure. Postoperative BNP levels decreased dramatically with the initiation of LVAD support. The levels correlated inversely with the degree of hemodynamic support rendered at various RPM settings of the HeartMate II (p < 0.001). Overall, BNP levels decreased significantly in 2 days after RPM increase. We observed a significant inverse correlation between the postoperative BNP levels and the degree of LVAD support. The effective LVAD support seems to result in a marked reduction in BNP levels, and monitoring serial BNP levels may be helpful in managing patients supported on continuous LVAD.

Postoperative Increase in B-Type Natriuretic Peptide Levels Predicts Adverse Outcome After Cardiac Surgery

To evaluate the prognostic implication of changes in postoperative B-type natriuretic peptide (BNP) concentrations in patients undergoing cardiopulmonary bypass for cardiac surgery. A retrospective analysis of prospectively collected clinical data. Cardiothoracic surgery and an intensive care unit (ICU) in a university hospital. The present study included a total of 407 consecutive patients undergoing cardiac surgery. None. 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. 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.

B-type Natriuretic Peptide: Perioperative Patterns in Congenital Heart Disease

B-type natriuretic peptide (BNP) has diagnostic, prognostic, and therapeutic roles in adults with heart failure. BNP levels in children undergoing surgical repair of congenital heart disease (CHD) were characterized broadly, and distinguishable subgroup patterns delineated. Prospective, blinded, observational case series. Academic, tertiary care, free-standing pediatric hospital. Children with CHD; controls without cardiopulmonary disease. Interventions. None. Preoperative cardiac medications/doses, CHD lesion types, perioperative BNP levels, intraoperative variables (lengths of surgery, bypass, cross-clamp), postoperative outcomes (lengths of ventilation, hospitalization, open chest; averages of inotropic support, central venous pressure, perfusion, urine output; death, low cardiac output syndrome (LCOS), cardiac arrest; readmission; and discharge medications). Median BNP levels for 102 neonatal and non-neonatal controls were 27 and 7 pg/mL, respectively. Serial BNP measures from 105 patients undergoing CHD repair demonstrated a median postoperative peak at 12 hours. The median and interquartile postoperative 24-hour average BNP levels for neonates were 1506 (782-3784) pg/mL vs. 286 (169-578) pg/mL for non-neonates (P < 0.001). Postoperative BNP correlated with inotropic requirement, durations of open chest, ventilation, intensive care unit stay, and hospitalization (r = 0.33-0.65, all P < 0.001). Compared with biventricular CHD, Fontan palliations demonstrated lower postoperative BNP (median 150 vs. 306 pg/mL, P < 0.001), a 3-fold higher incidence of LCOS (P < 0.01), and longer length of hospitalization (median 6.0 vs. 4.5 days, P= 0.01). Perioperative BNP correlates to severity of illness and lengths of therapy in the CHD population, overall. Substantial variation in BNP across time as well as within and between CHD lesions limits its practical utility as an isolated point-of-care measure. BNP commonly peaks 6-12 hours postoperatively, but the timing and magnitude of BNP elevation demonstrates notable age-dependency, peaking earlier and rising an order of magnitude higher in neonates. In spite of higher clinical acuity, non-neonatal univentricular CHD paradoxically demonstrates lower BNP levels compared with biventricular physiologies.

Comparison of the Utility of Preoperative versus Postoperative B-type Natriuretic Peptide for Predicting Hospital Length of Stay and Mortality after Primary Coronary Artery Bypass Grafting

Preoperative B-type natriuretic peptide (BNP) is known to predict adverse outcomes after cardiac surgery. The value of postoperative BNP for predicting adverse outcomes is less well delineated. The authors hypothesized that peak postoperative plasma BNP (measured postoperative days 1-5) predicts hospital length of stay (HLOS) and mortality in patients undergoing primary coronary artery bypass grafting, even after adjusting for preoperative BNP and perioperative clinical risk factors. This study is a prospective longitudinal study of 1,183 patients undergoing primary coronary artery bypass grafting surgery. Mortality was defined as all-cause death within 5 yr after surgery. Cox proportional hazards analyses were conducted to separately evaluate the associations between peak postoperative BNP and HLOS and mortality. Multivariable adjustments were made for patient demographics, preoperative BNP concentration, and clinical risk factors. BNP measurements were log10 transformed before analysis. One hundred fifteen deaths (9.7%) occurred in the cohort (mean follow-up = 4.3 yr, range = 2.38-5.0 yr). After multivariable adjustment for preoperative BNP and clinical covariates, peak postoperative BNP predicted HLOS (hazard ratio [HR] = 1.28, 95% CI = 1.002-1.64, P = 0.049) but not mortality (HR = 1.62, CI = 0.71-3.68, P = 0.25), whereas preoperative BNP independently predicted HLOS (HR = 1.09, CI = 1.01-1.18, P = 0.03) and approached being an independent predictor of mortality (HR = 1.36, CI = 0.96-1.94, P = 0.08). When preoperative and peak postoperative BNP were separately adjusted for within the clinical multivariable models, each independently predicted HLOS (preoperative BNP HR = 1.13, CI = 1.05-1.21, P = 0.0007; peak postoperative BNP HR = 1.44, CI = 1.15-1.81, P = 0.001) and mortality (preoperative BNP HR = 1.50, CI = 1.09-2.07, P = 0.01; peak postoperative BNP HR = 2.29, CI = 1.11-4.73, P = 0.02). Preoperative BNP may be better than peak postoperative BNP for predicting HLOS and longer term mortality after primary coronary artery bypass grafting surgery.

The Proportion of BNP Decline after Left Ventricular Assist Device Implantation Predicts Length of Survival after Surgery

Objective: Differences in B-type natriuretic peptide (BNP) values before and after left ventricular assist device (LVAD) surgery were evaluated as a predictor of survival after the surgery. Background: The impact of reduction of pre-operative BNP values, following LVAD surgery, on post-operative survival in heart failure (HF) patients is not known. Methods: Among a total of 287 patients who underwent LVAD surgery at Columbia University Medical Center between 2000 and 2010, 72 patients who had plasma BNP measurements at both 1 week before and 1 month after surgery were enrolled. Patients were divided into 2 groups according to % change of BNP value through surgery (% BNP change): greater (group A) or less than (group B) the median % BNP change. Result: Neither pre-operative nor post-operative BNP values were significantly correlated with post-surgical survival. The % BNP change was significantly correlated with post-surgical survival. Clinical characteristics, laboratory examination, and hemodynamics before and after surgery were not different between the two groups. Group A patients showed significantly better survival at 100 and 200 post-surgical days compared to group B (86.1 % vs. 74.6 %, 80.6 % vs. 54.5%, p=0.0399, respectively). Conclusion: The % BNP change could predict survival after LVAD surgery.

Does B-type Natriuretic Peptide or Its Gene Polymorphism Predict Patient Outcome after Coronary Artery Bypass Graft Surgery?

We read with great interest the research article by Fox et al. 1on genetic variation within defined regions of the NPPA /NPPB and NPR3 natriuretic peptide system genes as predictors for ventricular dysfunction after coronary artery bypass graft surgery. What concerns us as clinicians is the relation between those biomarkers and postoperative outcome, which can facilitate the preoperative risk evaluation. This article raised a good question: whether B-type natriuretic peptide (BNP) or its gene polymorphism predicts the prognosis in patients undergoing coronary artery bypass graft surgery.It is well known that a gene's function is mediated by expression of a specific protein. BNP has been established as a prognostic indicator in adults with congestive heart failure2and coronary artery disease,3whereas single nucleotide polymorphisms (SNPs) in the NPPB gene significantly impact BNP levels.4In the article by Dr. Fox et al. , there was mention that genetic variation within NPPA /NPPB and NPR3 genes was associated with risk of ventricular dysfunction after adjustment for preoperative BNP level and clinical factors. However, the authors did not directly analyze the relation between SNPs of these BNP genes with BNP level, especially postoperative BNP, whose level was not provided. Previous study has shown that early postoperative BNP levels correlate significantly with the ensuing duration of inotropic support and duration of hospitalization.5Therefore, we considered that SNPs of BNP genes could affect postoperative BNP rather than preoperative BNP and then predicted the prognosis, because expression of those genetic loci could be up- or down-regulated by mechanical stretch, ischemic injury, hypoxia, or even inflammatory mediators during surgery.6And the analysis should include both preoperative and postoperative BNP levels in this study.We think that the predictive pathway should be: SNPs of BNP–BNP level–clinical prognosis. If this hypothesis is established, it is postoperative BNP rather than SNPs of BNP that directly predicts ventricular dysfunction. Further investigations are still required to elucidate how BNP and its SNPs relate to development of postoperative ventricular dysfunction.*West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China. benbinliu@hotmail.com

Relationship between B-type natriuretic peptide levels and echocardiographic indices of left ventricular filling pressures in post-cardiac surgery patients

BackgroundB-type natriuretic peptide (BNP) is increased in post-cardiac surgery patients, however the mechanisms underlying BNP release are still unclear. In the current study, we aimed to assess the relationship between postoperative BNP levels and left ventricular filling pressures in post-cardiac surgery patients.MethodsWe prospectively enrolled 134 consecutive patients referred to our Center 8 ± 5 days after cardiac surgery. BNP was sampled at hospital admission and related to the following echocardiographic parameters: left ventricular (LV) diastolic volume (DV), LV systolic volume (SV), LV ejection fraction (EF), LV mass, relative wall thickness (RWT), indexed left atrial volume (iLAV), mitral inflow E/A ratio, mitral E wave deceleration time (DT), ratio of the transmitral E wave to the Doppler tissue early mitral annulus velocity (E/E').ResultsA total of 124 patients had both BNP and echocardiographic data. The BNP values were significantly elevated (mean 353 ± 356 pg/ml), with normal value in only 17 patients (13.7%). Mean LVEF was 59 ± 10% (LVEF ≥50% in 108 pts). There was no relationship between BNP and LVEF (p = 0.11), LVDV (p = 0.88), LVSV (p = 0.50), E/A (p = 0.77), DT (p = 0.33) or RWT (p = 0.50). In contrast, BNP was directly related to E/E' (p < 0.001), LV mass (p = 0.006) and iLAV (p = 0.026). At multivariable regression analysis, age and E/E' were the only independent predictors of BNP levels.ConclusionIn post-cardiac surgery patients with overall preserved LV systolic function, the significant increase in BNP levels is related to E/E', an echocardiographic parameter of elevated LV filling pressures which indicates left atrial pressure as a major determinant in BNP release in this clinical setting.

Natriuretic Peptide System Gene Variants Are Associated with Ventricular Dysfunction after Coronary Artery Bypass Grafting

Ventricular dysfunction (VnD) after primary coronary artery bypass grafting is associated with increased hospital stay and mortality. Natriuretic peptides have compensatory vasodilatory, natriuretic, and paracrine influences on myocardial failure and ischemia. The authors hypothesized that natriuretic peptide system gene variants independently predict risk of VnD after primary coronary artery bypass grafting. A total of 1,164 patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass at two institutions were prospectively enrolled. After prospectively defined exclusions, 697 patients of European descent (76 with VnD) were analyzed. VnD was defined as need for at least 2 new inotropes and/or new mechanical ventricular support after coronary artery bypass grafting. A total of 139 haplotype-tagging single nucleotide polymorphisms (SNPs) within 7 genes (NPPA, NPPB, NPPC, NPR1, NPR2, NPR3, CORIN) were genotyped. SNPs univariately associated with VnD were entered into logistic regression models adjusting for clinical covariates predictive of VnD. To control for multiple comparisons, permutation analyses were conducted for all SNP associations. After adjusting for clinical covariates and multiple comparisons within each gene, seven NPPA/NPPB SNPs (rs632793, rs6668352, rs549596, rs198388, rs198389, rs6676300, rs1009592) were associated with decreased risk of postoperative VnD (additive model; odds ratios 0.44-0.55; P = 0.010- 0.036) and four NPR3 SNPs (rs700923, rs16890196, rs765199, rs700926) were associated with increased risk of postoperative VnD (recessive model; odds ratios 3.89-4.28; P = 0.007-0.034). Genetic variation within the NPPA/NPPB and NPR3 genes is associated with risk of VnD after primary coronary artery bypass grafting. Knowledge of such genotypic predictors may result in better understanding of the molecular mechanisms underlying postoperative VnD.

B-Type Natriuretic Peptide as a Predictor of Postoperative Heart Failure After Aortic Valve Replacement

B-type natriuretic peptide (BNP) has been established as a biomarker for heart failure. The objective was to evaluate BNP measured on arrival in the intensive care unit (ICU) as a predictor for heart failure defined as need for inotropic support or IABP beyond 24 hours postoperatively after aortic valve replacement. A prospective, observational study. A cardiothoracic surgery unit at a tertiary level hospital. One hundred sixty-one patients undergoing aortic valve replacement. Two levels of BNP were evaluated: the median (BNP >133 pg/mL) and a cutoff (BNP >82 pg/mL) based on receiver-operating characteristic (ROC) analysis. Uni- and multivariate analysis were performed to identify predictors of postoperative heart failure. Patients with postoperative heart failure (n = 37) showed a more than 10-fold increase in 30-day mortality (8.1%, 3/37) compared with patients without postoperative heart failure (0.8%, 1/124) (p = 0.038). Elevated postoperative BNP levels were identified as an independent predictor of postoperative heart failure: BNP >82 pg/mL (p = 0.004) and BNP >133 pg/mL (p = 0.013). The area under the ROC curve for BNP as a predictor of postoperative heart failure was 0.69. Postoperative heart failure after aortic valve replacement is still a very serious condition with increased early mortality. The results of the present study suggest that an elevated BNP level on arrival in the ICU is an independent predictor of postoperative heart failure after aortic valve replacement. In the authors' opinion, an increased BNP level on arrival in the ICU may support early diagnosis and allow optimal management of heart failure after aortic valve replacement.

B‐Type Natriuretic Peptide (BNP) in Patients Undergoing Mitral Valve Surgery

Plasma B-type natriuretic peptide (BNP) level may be increased in patients with valvular disease. Recent studies have suggested that in patients undergoing aortic valve replacement, an increased preoperative BNP is associated with a worse operative outcome. Little is known about the perioperative value of BNP in patients undergoing mitral valve (MV) surgery. We measured the preoperative and postoperative BNP levels in this population and analyzed the impact of the increased BNP level on surgical outcome. From March 2004 to February 2005, 42 patients (mean age 64 +/- 12 years, 18 [42%] male) were enrolled in a prospective study. All patients underwent surgery for severe mitral regurgitation. The mean ejection fraction was 49 +/- 13%, and 26 (62%) patients presented with atrial fibrillation (AF). The median preoperative and postoperative BNP levels were 108 (9.7 to 995) and 357 (143 to 904) pg/mL, respectively (p = 0.002). Heart failure (p = 0.03), atrial fibrillation (AF) (p = 0.01), and ejection fraction (p = 0.01) were associated with an increased preoperative BNP level. In a multivariate analysis, the only independent predictor of the increased BNP level was AF (p = 0.01). In a univariate analysis, the preoperative BNP level was a significant predictor for inotropic support (p < 0.001), ventilation time (p = 0.003), intensive care unit (ICU; p = 0.01), and hospital length of stay (p = 0.02). In the multivariate analysis, BNP was not a predictor of these variables. Preoperative plasma BNP level presents with a high individual variability in patients with MV regurgitation. AF was the only independent predictor of an increased preoperative BNP level. The preoperative BNP level was not a predictor of surgical outcome. Further studies are required to confirm these findings and evaluate the potential role of this marker for patient selection.