Nathalie Valli

Review of 10 years of the clinical use of brain natriuretic peptide in cardiology

Ten years ago brain natriuretic peptide (BNP), the second compound of a family of polypeptide hormones named natriuretic peptides was identified. This peptide has great pathophysiologic importance as a stress-induced cardiac hormone secreted from ventricles, and it rises in several cardiac diseases. It promotes natriuresis and diuresis, acts as a vasodilator, and antagonizes the vasoconstrictor effects of the renin-angiotensin-aldosterone system. The measurement of this peptide in blood by immunoassay has shown promise over the past decade in clinical diagnosis and prognosis. Because heart failure is a major health problem worldwide, BNP is proposed as a biochemical marker that might provide a useful screening test to select patients for further cardiac investigations. Such a hormone assay is inexpensive and available. The implications of BNP in diagnosis, prognosis, and therapy will be reviewed.

Stability of brain natriuretic peptide (BNP) in human whole blood and plasma.

Abstract Brain natriuretic peptide is proposed as a biochemical marker which could provide a useful screening test to select patients for further cardiac investigations in heart failure. The applicability of such a biochemical test in clinics, hospital wards, and clinical laboratories is dependent on its ease of use and on the complexity of sample handling. The present study was undertaken to evaluate the stability of brain natriuretic peptide under a number of different handling conditions (sample collection, storage temperatures, freezing temperatures) assayed with a commercially available kit. The results clearly demonstrate that brain natriuretic peptide is stable at room temperature for 24 hours, or in up to 30°C for 12 hours in the presence and absence of aprotinin, on the condition that brain natriuretic peptide is assayed within one month (frozen at −20°C) after blood collection. The presence of aprotinin prevents brain natriuretic peptide degradation in samples preserved for more than 1 month at −20°C before assay.

A validation of a flow quantification by MR phase mapping software

AIM We evaluated a Siemens software of flow quantification (FQ) by MR phase mapping, in the framework of a common practical use. METHODS Experiments with a laminar flow phantom and in vivo pulsatile flow were performed. In particular, FQ in ascending aorta was investigated in healthy volunteers. RESULTS AND CONCLUSION Flow phantom experiments reveal that the FQ slightly underestimates (8% on the average) actual velocities (mean velocities over a vessel area), and also that velocity uncertainties are related to the encoding velocity value, whatever the measured velocity. Furthermore, using well characterized working criteria, we found low intraobserver variability and negligible interobserver variability in ascending aorta FQs. The role played by the choice of reference area in FQ accuracy is emphasized. When recording several cardiac cycles during the same acquisition, it is shown that the FQ software may provide erroneous results. Several comments for FQ software use in the ascending aorta are added.

Assessment of brain natriuretic peptide in patients with suspected heart failure: comparison with radionuclide ventriculography data

BACKGROUND The aim of the study was to prospectively evaluate patients with suspected or known heart disease using plasma brain natriuretic peptide (BNP) measurement and radionuclide ventriculography to examine whether left ventricular dysfunction is associated with an abnormal rise of BNP concentration. METHODS Patients (n=153) and controls (n=14) underwent radionuclide ventriculography to determine Left ventricular Ejection Fraction (LVEF) and measurement of plasma BNP concentration using a commercial kit. RESULTS Plasma BNP concentration in controls was significantly lower than that in patients whatever the stage of the disease, significantly lower than that of patients with normal LVEF (LVEF>55%); than that of patients with altered LVEF (LVEF< or =40%); and than that of patients with moderately reduced LVEF (40%<LVEF< or =5%). Comparisons between groups of patients showed that the more severe the disease, the higher the BNP level. From the ROC curve, a plasma BNP concentration of 52 pg/ml was attached to a 85% sensitivity and 82% specificity in identifying patients with LVEF< or =40%. CONCLUSIONS Plasma BNP concentration provides a reliable and sensitive marker of LV systolic dysfunction evaluated by a nuclear medicine technique, and could be a potential screening test to identify patients for additional investigations.

Effect of right ventricular pacing in patients with complete left bundle branch block

The relation between left ventricular electromechanical delay and the acute hemodynamic effect of right ventricular pacing was studied in heart failure patients with and without complete left bundle branch block. Whereas right ventricular pacing provided a shorter electromechanical delay that correlated with an improvement in left ventricular function in patients with left bundle branch block, the converse was observed in patients without left bundle branch block.

Subarachnoid-pleural fistula complicating thoracoscopy: value of In-111 DTPA myeloscintigraphy.

A 63-year-old woman underwent thoracoscopy to remove a calcified herniated thoracic disc at the T8-T9 level, which was responsible of an incomplete motor paraplegia. Because of adhesions between the dura mater and the herniated disc, this procedure was complicated by the dural lesion, which was immediately sealed with fibrin glue and a pleural patch. The association of headaches, a pleural effusion, and clear drainage from the chest catheter alerted the surgeon to the presence of a subarachnoid-pleural fistula. In-111 DTPA scintimyelography seems to be more sensitive than CT myelography for showing a cerebrospinal fluid leakage. A second radionuclide cisternography performed after a second posterior surgical procedure revealed that the fistula was closing.

Characterisation, cloning and sequencing of a conformation-dependent monoclonal antibody to the α IIb β 3 integrin: interest for use in thrombus detection

The detection of newly formed thrombi is of primary importance in clinical medicine. The activated platelet is a potential target for the localization of thrombotic lesions in arteries. The integrin f IIb g 3 membrane changes conformation upon activation. A novel anti- f IIb g 3 monoclonal antibody (MAb), XIIF9, is described which recognizes an epitope whose expression was enhanced by activation. Radioiodinated XIIF9 bound to a single class of sites on the g 3 subunit, with 13600 - 2000 molecules bound per unstimulated platelet and a K d of 34.5 nM. Platelets stimulated with 0.5 U/ml of thrombin bound 66000 - 4000 molecules/cell ( K d = 51.6 nM). Moreover, XIIF9 binding to unstimulated platelets could be increased 4-fold by treatment of the f IIb g 3 complex with 5 mM EDTA. Thus, XIIF9 recognized an epitope on the g 3 subunit whose accessibility was increased upon thrombin activation or EDTA treatment. Sequence analysis of the gene segment encoding the XIIF9 heavy chain revealed interesting motifs shared with cyclic CX6-7C anti- f IIb g 3 peptides or with AC7, a published MAb specific for activated f IIb g 3 . In vivo experiments in atherosclerotic rabbits followed by immunohistological analysis, revealed a specific binding of XIIF9 on platelets engaged in thrombus formation, demonstrating real clinical potential for such MAbs in imaging.

Double-phase Tc-99m sestamibi scintigraphy in a patient with uremia and secondary hyperparathyroidism: an aid for subtotal parathyroidectomy.

Secondary hyperparathyroidism in patients with uremia is an indication for surgical resection of a parathyroid mass when medical control is ineffective. Different surgical techniques have been proposed. In cases of subtotal parathyroidectomy, one question is still debated: Which parathyroid gland must be left in situ or saved for frozen preservation? In this case report, the authors indicate how double-phase scintigraphy with Tc-99m sestamibi could help to answer this question.