N-terminal pro-B-type natriuretic peptide concentrations and long-term outcome after cardiac surgery: a prospective cohort study.

BACKGROUND: N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations predict cardiovascular outcome in many settings. There are very few data assessing the utility of NT-proBNP concentrations in the prediction of long-term outcome after cardiac surgery. We assessed the ability of NT-proBNP to predict 3 yr mortality compared with validated clinical risk prediction tools. METHODS: A secondary analysis of a prospectively recruited patient cohort of 1010 patients undergoing cardiac surgery. Baseline clinical details were obtained including EuroSCORE. Multi-variable modelling, area under the receiver operating characteristic curves (AUCs), and net reclassification improvement were utilized. RESULTS: NT-proBNP was a univariable predictor of 3 yr mortality but was no longer a significant predictor in a multivariable model (hazard ratio 1.00 per 250 ng litre(-1), 95% confidence interval 0.98-1.02, P=0.80). The relative and additive predictive values of the preoperative EuroSCORE (both additive and logistic versions) and NT-proBNP concentrations were compared. All were predictive of 3 yr mortality (P<0.001) with almost identical AUCs (0.71 for EuroSCORE, 0.70 for NT-proBNP). When either the EuroSCORE or NT-proBNP concentrations are known, the addition of the other does not improve the ability to predict 3 yr mortality. CONCLUSIONS: Preoperative NT-proBNP concentrations and the EuroSCORE have equivalent, and moderate, predictive accuracy for mortality 3 yr after cardiac surgery. EuroSCORE uses clinical data but is not routinely used for individual clinical risk prediction. NT-proBNP measurement would incur additional costs but can be measured quickly and objectively. With such similar predictive accuracy, factors such as the ease of calculation and cost will likely determine their use in clinical practice.

N-terminal pro-B-type natriuretic peptide is an independent predictor of all-cause mortality and MACE after major vascular surgery in medium-term follow-up.

OBJECTIVE: Recent interest has focussed on the role of biomarkers to predict outcome in patients undergoing major vascular surgery. We wished to determine if pre- and postoperative N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) levels could predict all-cause mortality (ACM; primary aim) and major adverse cardiac event (MACE) (secondary aim) in the medium-term follow-up in patients who have undergone elective major vascular surgery. METHOD: Patients who underwent major elective vascular surgery (n = 136) were followed up for up to 2 years. ACM and first MACE episode were identified from the case notes and the patient management system database of the hospital intranet. RESULTS: One patient was lost to follow-up. In the mean follow-up of 654 days, 27 (20%) died and 23 (17%) patients suffered a MACE. Receiver operator curve (ROC) analysis showed that a pre-operative NT-pro-BNP level with a cut-off of 359 pg ml(-1) had a sensitivity and specificity of 73% each (area under the curve (AUC) 80%, p < 0.001) in predicting ACM and sensitivity of 74% and specificity of 71% (AUC 75%, p < 0.001) to detect a MACE. The overall 2-year survival rate was 84%, 93% in the <359 pg ml(-1) group and 68% in the ≥359 pg ml(-1) group (p < 0.001). Following multivariate analysis, pre-operative NT-pro-BNP at a value of ≥359 pg ml(-1) remained an independent predictor of ACM (odds ratio 3.6 (confidence interval (CI): 1.6-8.1), p = 0.002) Postoperative NT-pro-BNP was a predictor of mortality but not a MACE. CONCLUSION: This study has shown that pre-operative NT-pro-BNP is an independent predictor of ACM and MACE on medium-term follow-up.

N-terminal pro-B-type natriuretic peptide levels and early outcome after cardiac surgery: a prospective cohort study.

BACKGROUND: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a powerful predictor of cardiovascular outcome in many circumstances. There are, however, limited data regarding the utility of NT-proBNP or BNP levels in patients undergoing cardiac surgery. The current study assesses the ability of NT-proBNP to predict early outcome in this setting. METHODS: One thousand and ten patients undergoing non-emergent cardiac surgery were recruited prospectively. Baseline clinical details were obtained and the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and Parsonnet score were calculated. Preoperative NT-proBNP levels were measured using the Roche Elecsys assay. The primary endpoint was 30 day mortality. RESULTS: Median NT-proBNP levels were 624 ng litre(-1) among patients who died within 30 days of surgery (n=29), compared with 279 ng litre(-1) in survivors [odds ratio (OR) 1.03 per 250 ng litre(-1), 95% confidence interval 1.01-1.05, P=0.001). NT-proBNP levels remained predictors of 30 day mortality in models including either the additive EuroSCORE (OR 1.03 per 250 ng litre(-1), P=0.01), the logistic EuroSCORE (OR 1.03 per 250 ng litre(-1), P=0.004), or the Parsonnet score (OR 1.02 per 250 ng litre(-1), P=0.04). Levels of NT-proBNP were also predictors of prolonged (>1 day) stay in the intensive care unit (OR 1.03 per 250 ng litre(-1), P<0.001) and of a hospital stay >1 week (OR 1.07 per 250 ng litre(-1), P<0.001). They remained predictive of these outcomes in regression models that included either the EuroSCORE or the Parsonnet score and in a model that included all study variables. CONCLUSIONS: NT-proBNP levels predict early outcome after cardiac surgery. Their prognostic utility is modest-but is independent of traditional indicators and conventional risk prediction scores.

Socio-economic status and early outcome from coronary artery bypass grafting.

OBJECTIVE: To determine the effects of socio-economic status (SES) on the outcome of coronary artery bypass grafting (CABG). DESIGN: Prospective cohort study. SETTING: Regional cardiac surgical unit. PATIENTS: 1994 consecutive patients undergoing non-emergency CABG. MEASURES: SES was determined from the patient's postcode using Carstairs tables. The primary end-point was all-cause mortality at 30 days. RESULTS: There were 50 deaths (2.5%) within 30 days of surgery. A higher Carstairs score demonstrated a trend towards increased 30-day mortality (odds ratio (OR) 1.09 per unit, 95% CI 1.00 to 1.20, p = 0.06). In a backward conditional model, including other predictors of early mortality, Carstairs scores were independently predictive (OR 1.12 per unit, 95% CI 1.01 to 1.24, p = 0.02). In a model including only Carstairs scores and the EuroSCORE, both were independent predictors of this outcome (OR for Carstairs score 1.11 per unit, 95% CI 1.00 to 1.22, p = 0.04). The 30-day mortality increases in each quartile of Carstairs scores, with patients in quartile 4 (most deprived) at significantly higher risk compared with quartile 1 (uncorrected OR 2.53 per unit, 95% CI 1.04 to 6.15; OR corrected for EuroSCORE, 2.56 per unit, 95% CI 1.03 to 6.34, p = 0.04 for both). Similarly, patients in the least affluent quartile were twice as likely to suffer a serious complication as those in the most affluent quartile (OR 2.14 per unit, 95% CI 1.32 to 3.46, p = 0.002). This increased risk was also independent of the EuroSCORE. CONCLUSIONS: Lower SES is associated with a poorer early outcome following CABG and is independent of other recognised risk factors.

The utility of B-type natriuretic peptide in predicting postoperative cardiac events and mortality in patients undergoing major emergency non-cardiac surgery.

B-type natriuretic peptide (BNP) levels predict cardiovascular risk in several settings. We hypothesised that they would identify individuals at increased risk of complications and mortality following major emergency non-cardiac surgery. Forty patients were studied with a primary end-point of a new postoperative cardiac event, and/or development of significant ECG changes, and/or cardiac death. The main secondary outcome was all-cause mortality at 6 months. Pre-operative BNP levels were higher in 11 patients who suffered a new postoperative cardiac event (p = 0.001) and predicted this outcome with an area under the receiver operating characteristic curve of 0.85 (CI = 0.72-0.98, p = 0.001). A pre-operative BNP value > 170 pg x ml(-1) has a sensitivity of 82% and a specificity of 79% for the primary end-point. In this small study, pre-operative BNP levels identify patients undergoing major emergency non-cardiac surgery who are at increased risk of early postoperative cardiac events. Larger studies are required to confirm these data.

Utility of B-type natriuretic peptide in predicting perioperative cardiac events in patients undergoing major non-cardiac surgery.

BACKGROUND: B-type natriuretic peptide (BNP) levels predict cardiovascular risk in several settings. We hypothesized that they would identify individuals at increased risk of early cardiac complications after major non-cardiac surgery. The current study tests this hypothesis. METHODS: Two hundred and four patients undergoing major non-cardiac surgery were studied. The primary end-point was the development of acute myocardial injury [defined as cardiac troponin I (cTnI) level > 0.32 ng ml(-1)] or death in the 3 days after surgery. RESULTS: Preoperative BNP levels were raised in patients who died or suffered perioperative myocardial injury (median 52.2 vs 22.2 pg ml(-1), P = 0.01) and BNP predicted this outcome with an area under the receiver operating characteristic curve of 0.72 [95% confidence interval (CI) 0.59-0.86, P = 0.01]. A preoperative BNP value > 40 pg ml(-1) was associated with an increased risk of death or perioperative myocardial injury [odds ratio (OR) 6.8, 95% CI 1.8-25.9, P = 0.003], and remained independently predictive after correction for the Revised Cardiac Risk Index. Preoperative BNP levels were higher in patients who exhibited new onset atrial fibrillation or ST/T-wave changes on their postoperative ECG (median 50.5 vs 22.5 pg litre(-1), P = 0.01). They were also higher in patients who had either elevation of cTnI > 0.32 ng ml(-1) or postoperative ECG abnormalities (median 50.4 vs 21.5 pg ml(-1), P < 0.001). CONCLUSIONS: In the setting of major non-cardiac surgery, preoperative BNP levels are higher in patients who experience perioperative death and myocardial injury. Larger studies are required to confirm these data and to clarify what BNP levels may add to existing methods of risk stratification.

B-type natriuretic peptide and the prediction of outcome in patients admitted to intensive care.

B-type natriuretic peptide is known to predict outcome in congestive cardiac failure and myocardial infarction. We aimed to determine whether measurement of B-type natriuretic peptide would predict hospital mortality in patients admitted to an intensive care unit. We conducted a prospective observational cohort study in 78 consecutive patients. Demographics, clinical details and clinical outcomes were recorded. Admission and 24 h B-type natriuretic peptide and cardiac troponin I levels were measured. B-type natriuretic peptide and cardiac troponin I levels taken on intensive care admission and 24 h after admission did not accurately predict hospital mortality for all patients, including patients with severe sepsis or septic shock (all p > 0.05). B-type natriuretic peptide levels were higher in patients with severe sepsis and septic shock (p = 0.02), in patients > or = 65 years (p = 0.04) and in patients with raised creatinine > or = 110 micromol.l(-1) (p = 0.02). We concluded that B-type natriuretic peptide, measured soon after admission to intensive care, does not usefully predict outcome after intensive care.

A prospective study to evaluate the role of complexed prostate specific antigen and free/total prostate specific antigen ratio for the diagnosis of prostate cancer.

PURPOSE: Patients are increasingly undergoing prostatic biopsy to identify localized prostate cancer. The decision to perform a biopsy is often made on the basis of total prostate specific antigen (PSA). However, this value lacks adequate specificity for this task. We evaluate the role that a number of these tests, including the Bayer complexed PSA (Bayer Diagnostics, Tarrytown, New York) and free/total PSA ratio, may have in our clinical practice. MATERIALS AND METHODS: A total of 160 consecutive patients attending a prostate assessment clinic were enrolled during an 18-month period in our study. All patients had a previously recorded total PSA (range 2.6 to 20.0 ng./ml.). Before transrectal ultrasound biopsy of the prostate gland, a blood sample was taken with patient consent. The findings on ultrasound were then recorded, including prostate volume. Serum samples were immediately sent for subsequent storage and analysis. RESULTS: Of the patients enrolled 109 had benign histology while 51 had prostatic carcinoma. The 2 patient groups were well matched for age. In our series patients with prostate cancer had significantly smaller prostates and higher mean total PSA. At a high sensitivity, such as 95%, it appeared that Bayer complexed PSA performed better than the other tests and ratios, with an estimated specificity of 24.8% compared with 17.4% for Bayer total PSA and 15.6% for Abbott free/total PSA (Abbott Laboratories, Abbott Park, Illinois). Receiver operator characteristics curves were drawn, and when the areas under them were calculated, we demonstrated that the area under the curve for Bayer complexed PSA (0.706) was between the values for total PSA (0.671) and free/total PSA ratio (0.731). However, the only statistically significant improvement in performance was in Bayer complexed PSA over the total PSA assays. CONCLUSIONS: Our study revealed that the overall diagnostic performance of Bayer complexed PSA appears to be better than the other PSA tests and ratios studied. The use of Bayer complexed PSA may lead to a reduction in the number of men undergoing unnecessary prostatic biopsy.

The clinical application of a urine albumin:creatinine ratio point-of-care device.

INTRODUCTION: Microalbuminuria is an accepted predictive marker for the early detection of renal disease and the identification of patients at high risk of developing complications of diabetes and hypertension. The Bayer Clinitek 50 is a urine chemistry point-of-care analyser for the semi-quantitative measurement of albumin and creatinine and calculation of albumin:creatinine ratio (ACR). METHOD: Urine samples were obtained from 252 consecutive patients attending a city center diabetic clinic, and from 40 patients on admission to the ICU. Albumin and creatinine measurements were carried out using the Clinitek 50 and by the central laboratory. RESULTS: The Clinitek 50 results agreed with the central laboratory results in 89% of the diabetic patient samples and 80% of the ICU patient samples. Excluding samples defined as normal by the Clinitek 50 (ACR<3.4 mg/mmol) would have resulted in an 80% reduction in samples sent to the lab for further quantification. The average length of stay in the group of ICU patients with normal ACR was significantly less than for those patients with an abnormal ACR (p<0.005). CONCLUSIONS: The Clinitek 50 provides useful, immediate clinical information regarding the microalbuminuria status for use in the diabetic clinic setting or as a potential immediate risk management tool in intensive care.

Transient 5-oxoprolinuria (pyroglutamic aciduria) with systemic acidosis in an adult receiving antibiotic therapy.

5-Oxoprolinuria is a recognized condition with increased urinary excretion of 5-oxoproline and is associated with a variety of inborn metabolic defects involving the series of enzyme-linked reactions known as the gamma-glutamyl cycle. We report the unusual case of a 35-year-old woman who initially presented with staphylococcal pneumonia but went on to develop a transient high anion gap metabolic acidosis. The development and subsequent complete recovery from this acidosis were subsequently shown to be related in time to the intravenous administration of the antibiotics flucloxacillin and netilmicin. Analysis of the patient's urine for organic acids revealed massively increased excretions of 5-oxoproline at the peak of her acidosis. We suggest that this patient developed a transient disturbance in the gamma-glutamyl cycle involving the 5-oxoprolinase step, which resulted in accumulation of 5-oxoproline that caused a severe high anion gap metabolic acidosis. The administered antibiotics remain as possible causative agents.