Baseline natriuretic peptide levels in relation to myocardial ischemia, troponin T release and heart rate variability in patients undergoing major vascular surgery.
ABSTRACT This study was conducted to determine the association between baseline N-terminal pro-B-type natriuretic peptide (NT-proBNP) and myocardial ischemia, troponin T release and heart rate variability (HRV) in patients undergoing major vascular surgery.
In a prospective study, 182 vascular surgery patients were evaluated by clinical risk factors, dobutamine stress echocardiography and baseline NT-proBNP levels. Myocardial ischemia was detected by continuous 12-lead electrocardiographic monitoring starting 1 day before to 2 days after surgery. Troponin T (>0.03 ng/ml) was measured on day 1, 3 and 7 postoperatively and before discharge. HRV was measured at the day prior to surgery.
The median NT-proBNP level was 184 ng/l (interquartile range: 79-483 ng/l). Myocardial ischemia was detected in 21% and troponin T release in 17% of patients. After adjustment for clinical risk factors and stress echocardiography results, higher NT-proBNP levels (per 1 ng/l increase in the natural logarithm of NT-proBNP) were associated with a higher incidence of myocardial ischemia (odds ratio: 1.59, 95% confidence interval: 1.21-2.08, P<0.001) and troponin T release (odds ratio: 1.76, 95% confidence interval: 1.33-2.34, P<0.001). The optimal cutoff value of NT-proBNP to predict ischemia and/or troponin T release was 270 ng/l (area under the curve: 0.70). Higher baseline NT-proBNP levels were also associated with a larger ischemic burden at electrocardiographic monitoring (r=0.22, P=0.03). No significant correlation, however, was found between NT-proBNP and preoperative HRV (r=-0.024, P=0.78).
Elevated baseline NT-proBNP levels are significantly associated with perioperative myocardial ischemia and troponin T release, but not with preoperative HRV in patients undergoing major vascular surgery.
- [show abstract] [hide abstract]
ABSTRACT: The present study tested the hypothesis that increased plasma brain natriuretic peptide (BNP) levels are related to cardiac autonomic dysfunction in type 2 diabetic patients. A total of 32 consecutive Japanese patients with type 2 diabetes were assigned to either a high-BNP (>or=18 pg/ml) group (n=12; age 57+/-13 years, mean+/-S.D.) or a normal-BNP (<18 pg/ml) group (n=20; 59+/-10 years). No patient had any overt structural heart disease. Cardiac autonomic function was assessed by measurements of baroreflex sensitivity (BRS), heart rate variability (HRV) and cardiac (123)I-metaiodobenzylguanidine (MIBG) scintigraphic findings. BRS was lower (p<0.005) in the high-BNP group than in the normal-BNP group. However, the components of HRV, and the early and delayed myocardial uptake of (123)I-MIBG and percentage washout rate of (123)I-MIBG were not significantly different between the groups. The plasma level of BNP negatively correlated with BRS (r=0.35, p=0.049). These findings suggest that increased plasma BNP levels were related to cardiac reflex parasympathetic dysfunction in our Japanese type 2 diabetic patients.Diabetes Research and Clinical Practice 04/2006; 72(1):12-9. · 2.74 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: Brain natriuretic peptide (BNP) is a 32 amino acid cardiac natriuretic peptide hormone originally isolated from porcine brain tissue. The human BNP gene is located on chromosome 1 and encodes the prohormone proBNP. The biologically active BNP and the remaining part of the prohormone, NT-proBNP (76 amino acids) can be measured by immunoassay in human blood. Cardiac myocytes constitute the major source of BNP related peptides. The main stimulus for peptide synthesis and secretion is myocyte stretch. Recently, cardiac fibroblasts have also been shown to produce BNP. Other neurohormones may stimulate cardiac BNP production in different cardiac cell types. In contrast to atrial natriuretic peptides (ANP/NT-proANP), which originate mainly from atrial tissue, BNP related peptides are produced mainly from ventricular myocytes. Ventricular (NT-pro)BNP production is strongly upregulated in cardiac failure and locally in the area surrounding a myocardial infarction. In peripheral organs BNP binds to the natriuretic peptide receptor type A causing increased intracellular cGMP production. The biological effects include diuresis, vasodilatation, inhibition of renin and aldosterone production and of cardiac and vascular myocyte growth. In mice BNP gene knockout leads to cardiac fibrosis, gene over-expression to hypotension and bone malformations. BNP is cleared from plasma through binding to the natriuretic peptide clearance receptor type C, but it seems relatively resistant to proteolysis by neutral endopeptidase NEP 24.11. Clearance mechanisms for NT-proBNP await further study. While the plasma concentration of NT-proBNP and BNP is approximately equal in normal controls, NT-proBNP plasma concentration is 2-10 times higher than BNP in patients with heart failure. This relative change in peptide levels may be explained by shifts in cardiac secretion and/or clearance mechanisms.European Journal of Heart Failure 04/2004; 6(3):257-60. · 5.25 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: To evaluate the predictive value of brain natriuretic peptide (BNP) for assessment of cardiac risk before non-cardiac surgery. Consecutively treated patients (947 men, 643 women) whose BNP was measured before non-cardiac surgery were studied. Clinical and ECG variables were evaluated to identify predictors of postoperative cardiac events. Events occurred in 6% of patients: 21 cardiac deaths, 20 non-fatal myocardial infarctions, 41 episodes of pulmonary oedema and 14 patients with ventricular tachycardia. All of these patients had raised plasma BNP concentrations (best cut-off point 189 pg/ml). The only independent predictor of postoperative events was BNP (odds ratio 34.52, 95% confidence interval (CI) 17.08 to 68.62, p < 0.0001). Clinical variables of Goldman's multifactorial index identified 18% of patients in class I, 40% in class II, 24% in class III and 18% in class IV preoperatively; postoperative event rates were 2%, 3%, 7% and 14%, respectively. BNP identified 60% of patients as having zero risk (BNP 0-100 pg/ml), 22% low risk (101-200 pg/ml), 14% intermediate risk (201-300 pg/ml) and 4% high risk (> 300 pg/ml); postoperative event rates were 0%, 5%, 12% and 81%, respectively. In this population of patients evaluated before non-cardiac surgery, BNP is an independent predictor of postoperative cardiac events. BNP > 189 pg/ml identified patients at highest risk.Heart (British Cardiac Society) 12/2006; 92(11):1645-50. · 5.01 Impact Factor