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Biomedical subjects

P O Collinson

Publications and source records attributed to P O Collinson.

At least 19 recordsLinked to original sources
PubMed2007

Maternal cardiac function in early pregnancies with high uterine artery resistance.

OBJECTIVE: To compare the maternal cardiac function and serum concentration of cardiac troponin T (cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in first-trimester patients, according to uterine artery Doppler velocimetry (UADV). METHODS: This cross-sectional study included singleton pregnancies with normal UADV (n=17) and abnormal UADV (n=19). Maternal echocardiography was performed and blood samples were taken at 11-14 weeks. Echocardiographic parameters included: (a) left ventricular (LV) long axis velocities; (b) atrial size; (c) LV filling pressure; (d) the ratio of peak mitral flow velocity in early diastole and early mitral annular diastolic velocity (E/Ea ratio); and (e) the E/flow propagation velocity ratio. The maternal serum concentrations of cTnT and NT-proBNP were determined by sensitive and specific immunoassays. RESULTS: Patients with abnormal UADV had higher estimated left ventricular filling pressure (P=0.004), higher E/Ea ratio (P=0.03), higher E/flow propagation ratio (P=0.02), and lower LV long axis velocity (P=0.02) than those with normal UADV. There were no significant differences in the maternal serum concentration of cTnT or NT-proBNP. CONCLUSIONS: Patients with abnormal UADV in the first trimester have higher left ventricular filling pressure and may have left ventricular systolic dysfunction.

Adult↗
PubMed2006

Best practice in primary care pathology: review 7.

This seventh best-practice review examines four series of common primary care questions in laboratory medicine: (1) blood count abnormalities 2; (2) cardiac troponins; (3) high-density lipoprotein cholesterol; and (4) viral diseases 2. The review is presented in a question-answer format, with authorship attributed for each question series. The recommendations are a précis of guidance found using a standardised literature search of national and international guidance notes, consensus statements, health policy documents and evidence-based medicine reviews, supplemented by Medline Embase searches to identify relevant primary research documents. The recommendations are not standards, but form a guide to be set in the clinical context. Most are consensus based rather than evidence based. They will be updated periodically to take account of new information.

Biomarkers↗
PubMed2006

Diagnostic and prognostic role of cardiac troponin I (cTnI) measured on the DPC Immulite.

OBJECTIVE: To evaluate the diagnostic and prognostic role of the Immulite cTnI assay for the detection of acute coronary syndromes (ACS). POPULATION: 150 males and 63 females with a median age of 63 years, range 28 to 88, and an interquartile range of 18 years were admitted within 24 h of chest pain and non-ST segment elevation ACS were studied. The median onset of symptoms was 3 h (range 0-23). METHODS: Venous samples were taken on admission (t = 0) and at 24 h (t = 24). The serum samples were assayed for CK, CK-MB and cTnT on an Elecsys 1010 (Roche Diagnostics, Lewes, UK). The cTnT assay CV was 5.5% at 0.32 microg/l and 5.4% at 6.0 microg/l, and the detection limit was 0.01 microg/l with an upper limit of 25 microg/l. For cTnI using the Immulite (DPC, Gwynedd, Wales), the detection limit was 0.1 microg/l, and the upper limit was 180 microg/l. Final diagnostic categorization was performed by both WHO and European Society of Cardiology criteria using cTnT as the diagnostic cardiac biomarker. Patients were followed for the major adverse cardiac events (MACE), endpoints cardiac death, AMI or need for urgent revascularization. ROC curves were constructed using final diagnosis. Outcome prediction was assessed by ROC curves and Kaplan-Meier survival curves. RESULTS: Both methods had equivalent diagnostic efficiency using WHO criteria for AMI. When ESC criteria were used the AUC for admission and 24 h cTnT and cTnI values were 0.945 vs. 0.910, P = 0.20 and 0.998 vs. 0.937, P = 0.005, respectively. Both methods predicted outcome as either death or MI or MACE and were not significantly different. CONCLUSION: The Immulite cTnI assay can be used for diagnosis and risk stratification in patients admitted with non-ST segment elevation acute coronary syndromes.

Adult↗
PubMed2006

Utility of admission cardiac troponin and "Ischemia Modified Albumin" measurements for rapid evaluation and rule out of suspected acute myocardial infarction in the emergency department.

OBJECTIVE: To assess if the combination of cardiac troponin (cTn) and Ischemia Modified Albumin (IMA) can be used for early exclusion of acute myocardial infarction (AMI). METHODS: Prospective consecutive admissions to the emergency department (ED) with undifferentiated chest pain were assessed clinically and by electrocardiography. A total of 539 patients (335 men, 204 women; median age 51.9 years) considered at low risk of AMI had blood drawn on admission. If the first sample was less than 12 hours from onset of chest pain, a second sample was drawn two hours later, at least six hours from onset of chest pain. Creatine kinase MB isoenzyme (CKMB) mass was measured on the first sample and CKMB mass and cTnT on the second sample. An aliquot from the first available sample was frozen and subsequently analysed for IMA. If cTnT had not been measured on the original sample cTnI was measured (n = 189). RESULTS: Complete data were available for 538/539 patients. IMA or cTn was elevated in the admission sample of all patients with a final diagnosis of AMI (n = 37) with IMA alone elevated in 2/37, cTn alone in 19/37, and both in 16/37. In 173/501 patients in whom AMI was excluded both tests were negative. In the non-AMI group 22 patients had elevation of both IMA and cTn in the initial sample, suggesting ischaemic disease. CONCLUSION: Admission measurement of cardiac troponin plus IMA can be used for early classification of patients presenting to the ED to assist in patient triage.

Adult↗
PubMed2005

Cardiac structural and functional abnormalities in end stage renal disease patients with elevated cardiac troponin T.

OBJECTIVES: To identify in a prospective observational study the cardiac structural and functional abnormalities and mortality in patients with end stage renal disease (ESRD) with a raised cardiac troponin T (cTnT) concentration. METHODS: 126 renal transplant candidates were studied over a two year period. Clinical, biochemical, echocardiographic, coronary angiographic, and dobutamine stress echocardiographic (DSE) data were examined in comparison with cTnT concentrations dichotomised at cut off concentrations of < 0.04 microg/l and < 0.10 microg/l. RESULTS: Left ventricular (LV) size and filling pressure were significantly raised and LV systolic and diastolic function parameters significantly impaired in patients with raised cTnT, irrespective of the cut off concentration. The proportions of patients with diabetes and on dialysis were higher in both groups with raised cTnT. With a cut off cTnT concentration of 0.04 microg/l but not 0.10 microg/l, significantly more patients had severe coronary artery disease and a positive DSE result. The total ischaemic burden during DSE was similar in cTnT positive and negative patients, irrespective of the cut off concentration used. LV end systolic diameter index and E:Ea ratio were independent predictors of cTnT rises > or = 0.04 microg/l and > or = 0.10 microg/l, respectively. Diabetes was independently associated with cTnT at both cut off concentrations. Mortality was higher in all patients with raised cTnT. CONCLUSIONS: Patients with ESRD with raised cTnT concentrations have increased mortality. Raised concentrations are strongly associated with diabetes, LV dilatation, and impaired LV systolic and diastolic function, but not with severe coronary artery disease.

Cardiomyopathy, Dilated↗
PubMed2005

Dobutamine stress echocardiography and cardiac troponin T for the detection of significant coronary artery disease and predicting outcome in renal transplant candidates.

AIMS: Ischaemic heart disease is the leading cause of mortality and morbidity in patients with end-stage renal disease (ESRD) and after renal transplantation. However, the optimal non-invasive test for coronary artery disease (CAD) diagnosis in this population has yet to be established. The aim of this study was to assess the diagnostic accuracy of dobutamine stress echocardiography (DSE) and baseline plasma cardiac troponin T (cTnT) for detecting significant CAD and predicting adverse cardiac events in patients referred for renal transplantation. METHODS: Coronary angiography, DSE, and baseline cTnT measurements were performed in 118 consecutive patients (mean age 52+/-12 years, 75 male) with ESRD (mean creatinine 608+/-272 micromol/L) referred for renal transplantation. The mean follow-up period was 1.32+/-0.48 years. Significant CAD was defined as a reduction in luminal diameter >70% by visual estimation in at least one major epicardial vessel. An abnormal DSE result defined as the development of a new regional wall motion abnormality in one or more normal resting segments or a deterioration of wall motion in one or more resting hypokinetic segments. A baseline cTnT>0.1 microg/L was taken as positive. RESULTS: Significant CAD in at least one vessel was present in 35 patients (30%). The number of patients with significant 3 vessel and 2 vessel disease was 6 and 7, respectively. An abnormal DSE result was present in 36 (31%) patients. Thirty-one (26%) had cTnT>0.1 microg/L. Sixty-four (54%) patients were on dialysis and 46 (39%) were diabetic. The sensitivity, specificity, positive and negative predictive values for DSE in detecting significant coronary artery disease were 88%, 94%, 86% and 95%, respectively. The same values for a raised cTnT were 54%, 62%, 40% and 74%, respectively. The combination of an abnormal DSE result and raised cTnT gave values of 61%, 91%, 76%, and 80%, respectively. Over the follow-up period, mortality was significantly higher in those with a raised baseline cTnT but not those with an abnormal DSE result or significant CAD. CONCLUSION: DSE is an accurate technique for the detection of significant CAD in renal transplant candidates. An elevated cTnT does not predict significant CAD in this population and when used in conjunction with DSE, reduces the sensitivity of the combined tests. cTnT is an important marker of prognosis in renal transplant candidates.

Adult↗
PubMed2005

Hypertriglyceridaemia and malignancy.

Severe hypertriglyceridaemia is a rare presentation usually associated with acute pancreatitis. We present two case reports of severe hypertriglyceridaemia occurring in patients with previous autoimmune disease and haematological and solid malignancies but no evidence of prior or concurrent pancreatitis or hyperlipidaemia. These case reports illustrate that haematological and solid organ malignancies and autoimmunity may be relevant as exacerbating factors in the presentation of severe type IV or V hypertriglyceridaemia.

Adult↗
PubMed2004

Analytical performance of the N terminal pro B type natriuretic peptide (NT-proBNP) assay on the Elecsys 1010 and 2010 analysers.

The Elecsys NT-proBNP assay is based on two polyclonal antibodies directed at residues 1-21 and 39-50 of the NT-proBNP molecule. Analytical performance was assessed using NCCLS protocol EP-5A using three serum pools in a preliminary study then as part of a multicentre evaluation (16 instruments in 8 hospitals). Using pools of 350 pg/l, 8700 pg/l and 13000 pg/l single site within run %CV was 0.7-1.6 (1010) and 1.2-1.5 (2010) and between run CV 5.3-6.7 (1010) and 4.4-5.0 (2010). In the multicentre evaluation within run CV was 1.0-2.5% with total imprecision 1.5-2.5% and between labs imprecision 3.8-4.0%. Functional sensitivity of <50 pg/l and measuring range to 35000 pg/l. There was excellent agreement between instrument platforms, y=0.97x+2.6; r=1.00 (n=215) for Elecsys 2010 (x) vs. Elecsys 1010 (y) and y=1.02x-0.3; r=1.00 (n=99) for Elecsys 2010 (x) vs. E 170 (y). Serum and heparin plasma samples showed good agreement but lower values were seen in EDTA plasma. Samples were stable for 7 days at room temperature; 21 days at 4 degrees C and for 5 freeze thaw cycles. Samples were obtained from a population of 1205 (671 male, 534 female) apparently healthy individuals screened by echocardiography and symptom questionnaire. There was poor correlation with NT-proANP (ELISA) (rs 0.33) and modest correlation with BNP (rs 0.89) with NT-proBNP values approximately 5 times greater than BNP (Biosite Triage). In a subset of 320 with normal ejection fraction (>50%) and no risk factors, NT-proBNP values increased with age and were higher in women than men.

Aged↗
PubMed2004

Role of "Ischemia modified albumin", a new biochemical marker of myocardial ischaemia, in the early diagnosis of acute coronary syndromes.

BACKGROUND: Diagnosis of cardiac ischaemia in patients attending emergency departments (ED) with symptoms of acute coronary syndromes is often difficult. Cardiac troponin (cTn) is sensitive and specific for the detection of myocardial damage but may not rise during reversible myocardial ischaemia. Ischemia Modified Albumin (IMA) has recently been shown to be a sensitive and early biochemical marker of ischaemia. METHODS AND RESULTS: This study evaluated IMA in conjunction with ECG and cTn in 208 patients presenting to the ED within three hours of acute chest pain. At presentation, a 12-lead ECG was recorded and blood taken for IMA and cardiac troponin T (cTnT). Patients underwent standardised triage, diagnostic procedures, and treatment. Results of IMA, ECG, and cTnT, alone and in combination, were correlated with final diagnoses of non-ischaemic chest pain, unstable angina, ST segment elevation, and non-ST segment elevation myocardial infarction. In the whole patient group, sensitivity of IMA at presentation for an ischaemic origin of chest pain was 82%, compared with 45% of ECG and 20% of cTnT. IMA used together with cTnT or ECG, had a sensitivity of 90% and 92%, respectively. All three tests combined identified 95% of patients whose chest pain was attributable to ischaemic heart disease. In patients with unstable angina, sensitivity of IMA used alone was equivalent to that of IMA and ECG combined. CONCLUSIONS: IMA is highly sensitive for the diagnosis of myocardial ischaemia in patients presenting with symptoms of acute chest pain.

Adult↗
PubMed2004

A prospective randomized controlled trial of point-of-care testing on the coronary care unit.

BACKGROUND: We report the results of a prospective randomized controlled trial comparing point-of-care testing (POCT) with central laboratory testing (CLT) in a six-bed coronary care unit in a district general hospital. METHODS: 263 consecutive admissions with chest pain and suspected acute coronary syndrome were randomized to measurement of cardiac troponin T by POCT or CLT only. Patient management was according to a pre-specified protocol utilizing clinical features, electrocardiographic changes and cardiac biomarkers (creatine kinase and cardiac troponin T) to define management. Outcome measures were diagnostic accuracy compared with CLT as 'gold standard', result turnaround time, mortality and length of stay in all patients and those with a protocol-driven early discharge policy. RESULTS: Diagnostic accuracy and mortality was equivalent in the POCT and CLT arm. Overall there was no difference in length of stay. In the pre-specified early discharge group (n = 64) there was a significant reduction in median length of non-coronary care unit stay (145.3 h versus 79.5 h) and overall hospital stay (209.3 h versus 149.9 h) in those randomized to POCT. CONCLUSION: A combination of rapid biochemical diagnosis and structured decision making reduces length of hospital stay.

Adult↗
PubMed2004

Evaluation of N-terminal pro-B type natriuretic peptide analysis on the Elecsys 1010 and 2010 analysers.

BACKGROUND: N-terminal pro-B type natriuretic peptide (NTpBNP) is a potential marker of cardiac failure. METHODS: The Roche Elecsys(trade mark) 1010 and 2010 assays for NTpBNP were evaluated for precision, sample stability, and correlation between sample types and with other natriuretic peptides. Samples from 290 individuals aged 45-89 years with no cardiovascular risk factors, renal failure, electrocardiogram changes, evidence of structural abnormalities, or wall motion abnormalities on echocardiography and with an ejection fraction >50% were used to provide reference NTpBNP ranges. RESULTS: The intra-assay imprecision was <10% across the analytical range and >3% at all concentrations analysed <30 ng/L. Inter-assay imprecision was 5.3-6.7% on the Elecsys 1010 and 4.4-5.0% on the Elecsys 2010, in the range 380-13000 ng/L. There was no statistically significant change in NTpBNP following storage in whole-blood samples at room temperature for 24 h before centrifugation; serum samples at room temperature for 7 days, at 4 degrees C for up to 11 days on clot-activation gel or 22 days separated from the gel. NTpBNP concentrations were stable throughout five freeze-thaw cycles. There was a close correlation between NTpBNP concentrations in matched serum, EDTA plasma and lithium-heparin plasma samples. NTpBNP and BNP were more closely associated than were N-terminal proatrial natriuretic peptide and NTpBNP. This association was stronger at lower concentrations. NTpBNP concentrations increased with age, with values higher in women than men. CONCLUSIONS: NTpBNP is a stable molecule that can be measured easily and precisely using the Roche Elecsys 1010 or 2010 immunoassay analysers.

Aged↗
PubMed2003

Multicentre evaluation of the diagnostic value of cardiac troponin T, CK-MB mass, and myoglobin for assessing patients with suspected acute coronary syndromes in routine clinical practice.

OBJECTIVE: To assess the diagnostic efficiency of the third generation cardiac troponin T assay in routine clinical practice. DESIGN: Prospective observational study of unselected consecutive admissions. SETTING: Multicentre study in 43 teaching and non-teaching hospitals in 13 countries. SUBJECTS: 1105 hospital admissions, median age 67 years (range 15-96 years, 63.7% male) with suspected acute coronary syndromes (72.3% of cases) or other non-specific symptoms where cardiac disease required exclusion (27.7%). INTERVENTIONS: Over the study period, myoglobin, creatine kinase MB isoenzyme (CK-MB), and cardiac troponin T where measured in parallel with conventional diagnostic tests. Final diagnostic classification involved standard ECG changes and CK-MB mass exceeding 5.0 microg/l. MAIN OUTCOME MEASURES: Diagnostic efficiency was assessed by receiver operator characteristic curve analysis including and excluding patients with unstable angina. RESULTS: Measurement of cardiac troponin T was diagnostically equivalent to CK-MB and both were better than myoglobin, with areas under the curve at 12 hours of 0.94, 0.99, and 0.80, respectively. Diagnostic criteria using CK-MB were inadequate and showed bias when patients with unstable angina were included. Elevations of cardiac troponin T did not occur when cardiac disease could be categorically excluded but were found in clinical conditions other than suspected acute coronary syndromes. CONCLUSIONS: CK-MB is unsuitable as a diagnostic gold standard even at the proposed lower threshold. A lower cut off for cardiac troponin T of 0.05 microg/l should be used for diagnosis of acute myocardial infarction. Diagnosis of acute myocardial infarction cannot be made solely on the basis of a cardiac troponin T result.

Adolescent↗
PubMed2003

Impact of European Society of Cardiology/American College of Cardiology guidelines on diagnostic classification of patients with suspected acute coronary syndromes.

BACKGROUND: Assessment of the relative diagnostic accuracy of investigation strategies for patients with suspected acute coronary syndromes (ACS). METHODS: A prospective observational study followed two groups of patients over a 3-month period in a UK district general hospital. Group one: all admissions with suspected ACS (n = 576); group two: non-cardiac in-patients who were suspected of developing ACS (n = 87). Both were investigated by full clinical history, examination and serial electrocardiographs (ECGs). Conventional World Health Organization (WHO) criteria for myocardial damage were compared with diagnosis based on cardiac troponin T (cTnT). Clinical discharge diagnosis based on conventional WHO criteria was compared with the review diagnosis based on measurement of cTnT. RESULTS: Diagnosis based on WHO criteria missed 58 patients (8.7%) admitted with suspected ACS who had high risk unstable angina. Thirty-three patients (5% of all admissions) who were diagnosed as non-Q wave acute myocardial infarction (AMI) were found to have normal troponin values and to have been incorrectly classified as AMI. CONCLUSIONS: Diagnostic strategies based on WHO criteria are inaccurate. The measurement of cTnT in all patients with suspected ACS would have increased the number of those with a diagnosis of AMI by 58 (8.7%), while avoiding inaccurate diagnosis in 33 (5%), therefore producing an absolute increase of 25/663 (3.8%) but a relative increase of 58/138 (42%). In patients with a primary diagnosis of suspected ACS, the overall increase in patients with a diagnosis of AMI will be 55 (9.5%), a relative increase of 55/118 (46.6%) but an absolute increase of 36/576 (6.3%).

Acute Disease↗