[Chronic pericarditis: CT and MR imaging features]. / Pourquoi réaliser un scanner et une IRM dans une péricardite chronique?

A diagnosis of constrictive pericarditis is suggested by the presence of pericardial thickening (>=4 mm in thickness) and abnormal motion of the interventricular septum. Additional findings have been reported: tubular appearance of the right or left ventricles, dilatation of the vena cava, atrial dilatation or abnormal diastolic expansion of one or both ventricles. In patients with suspected chronic pericarditis, CT can more easily demonstrate the presence of pericardial calcifications compared to US and MRI, as well as detect the presence of mediastinal adenopathy and lung lesions, suggesting tuberculosis. Septal motion analysis should be performed during protodiastole and systole using a cine technique with both CT and MR.

[Current indications for cardiac CT]. / Les indications actuelles du scanner cardiaque.

There is a need to define the current indications for coronary CT angiography (CCTA) even as technology continuously evolves. CCTA using 64 MDCT units has shown to be highly accurate for diagnosis of stenoses >or=50% on selected populations. It is currently used for its negative predictive value (96-98%). Stenosis quantification remains inferior to conventional coronary angiography with tendency to overestimate stenoses <70%. For diagnosis of coronary artery disease, CCTA is considered based on clinical findings (pre-test probability of coronary artery disease) and presence of myocardial ischemia on other functional studies. The main appropriate indications include: In the setting of acute coronary syndrome, CCTA excludes coronary artery disease with excellent NPV and good negative likelihood ratio (0.05) when ECG is non-contributory, 2 consecutive troponin levels at 6 hours are negative in a patient with low risk of coronary artery disease. In the setting of stable angina or atypical precordial chest pain, CCTA is indicated in patient with low to medium risk when functional test are non-contributory or unavailable, or ECG is non-interpretable. CCTA is a complement to coronary angiography for morphological evaluation of some lesions prior to angioplasty and stent placement (long segment occlusion, proximal lesions involving LAD and circumflex arteries). In selected patients, CCTA may replace coronary angiography prior to valvular surgery.

Left atrial volume assessed by ECG-gated computed tomography: Variations according to age, gender and time during the cardiac cycle.

PURPOSE: The purpose of this study was to retrospectively assess the accuracy of the maximal left atrial volume (LAVmax) measured at 75% of the cardiac cycle compared to the 40% measurements and to evaluate this volume according to age and gender. PATIENTS AND METHOD: A total of 150 patients with a mean age of 50±17 (SD) years (range: 21-79 years) were analyzed. There were 78 men and 72 women. LAVmax were measured from retrospective triphasic cardiac-gated multi-detector computed tomography (MDCT) data at the 40% (LAV40) and 75% (LAV75) of the RR cycle phases by a semi-automatic method. RESULTS: LAV40was 50.7±14mL/m2 and LAV75 was 42.5±13mL/m2. The difference was statistically significant. Considering the reference range of LAVmax reported in the literature, 33% of the patients had enlarged LA with LAV40 and only 17% with LAV75. These volumes were positively influenced by age but not by gender. The relationship between LAV75 and LAV40 was: LAV75=0.908 LAV40-3.486 (r2=0.92) or LAV40=1.1×LAV75+3.8 (r2=0.92). CONCLUSION: LAVmax measured at the 75% of the cardiac cycle phase significantly underestimates actual LAV leading to reconsider normal values. LAV40 can be computed from the measured value of LAV75 obtained on prospective ECG-gated MDCT.

[Idiopathic venous thromboembolic disease. risk factors for recurrence in 2006]. / Maladie veineuse thromboembolique idiopathique. Facteurs de risque de récidive en 2006.

The duration of anticoagulant therapy after a first attack of venous thromboembolic disease (VTE) is related to the risk of recurrence and the iatrogenic complication of bleeding. Recent prospective trials have provided information concerning the clinical and biological profiles of those at greatest risk of recurrence of deep vein thrombosis. The value of ultrasonic investigations and of D-Dimer measurements have also been assessed. The risk of recurrence is not negligible, about 10% in the first year after stopping treatment and 2/3 of recurrences occurring in the first two years. There are several risk factors for recurrence: male gender, past history of renal transplant, presence of malignant disease, proximal site of the initial thrombosis, initial presentation with pulmonary embolism, previous deep vein thrombosis and the co-existence of two thrombophilic factors. On the other hand, age, single deep vein thrombosis and a family history of deep vein thrombosis are not significantly related to increased risk. The presence of a residual thrombus at the end of treatment remains a subject of controversy. The risk of recurrence when the D-Dimers are normal one month after stopping the anticoagulants seems to be low, especially in cases of an associated thrombophilia. Finally, the risk of haemorrhage is related to the duration of oral anticoagulant therapy and the age of the patient. These trials have provided information for the issue of recommendations by consensus conferences and allow better economic evaluation of the duration of treatment after a first episode of deep vein thrombosis with respect to differing clinical situations.

Aspirin resistance: definitions, mechanisms, prevalence, and clinical significance.

Aspirin is the most commonly used therapeutic agent in prevention of vascular ischemic events. Aspirin exerts its antithrombotic effect primarily by interfering with the biosynthesis of thromboxane A2 (TXA2) and inhibition of TXA2 -dependent platelet aggregation. A meta-analysis of secondary prevention trials indicated that aspirin reduced major cardiovascular or cerebral events by 25%. This led to the widespread use of aspirin for prevention of cardiovascular events. However, it appears that aspirin antiplatelet effect is not uniform in all patients and previous studies estimated that 8-45% of the population were aspirin resistant. Furthermore, (i) the optimal dosage of aspirin for complete inhibition of platelet aggregation by physiological agonists (i.e arachidonic acid) is subject to great interindividual variability, (ii) the tests to detect aspirin resistance in vitro are subject to debate and (iii) the mechanisms by which some patients are resistant to aspirin in vitro remain to be determined. Despite these unresolved questions, recent clinical studies provide the reliable evidence that aspirin resistance correlates with confirmed clinical unresponsiveness, highlighting the clinical interest of determining the aspirin inhibitory effects on patients' platelets. In conclusion, discovery of aspirin resistance in individuals might be important in order to devise better anti-platelet strategies and improve our ability to prevent acute thrombotic complication.

Non-invasive antenatal RHD typing.

The existence of cell free fetal DNA, derived from apoptotic syncytiotrophoblast, in the maternal circulation has opened new possibilities of non-invasive prenatal diagnosis. Although still some technical problems exists, especially the lack of a generic positive control on the presence of fetal DNA and the aspecific amplification of background maternal DNA, non-invasive prenatal RHD typing has been successfully introduced in several laboratories, especially in Europe. The diagnostic accuracy reaches>99%. In the Netherlands PCR guided administration of antenatal anti-D prophylaxis is cost-effective and nearby. In this review the main characteristics and applications of cell free fetal DNA are discussed, with an emphasis on prenatal RHD genotyping.

Establishment of diagnostic reference levels in cardiac CT in France: a need for patient dose optimisation.

The objective of this study was to propose diagnostic reference levels (DRLs) for coronary computed tomography angiography (CCTA), in the context of a large variability in patient radiation dose, and the lack of European recommendations. Volume Computed Tomography Dose Index (CTDIvol) and dose-length product (DLP) were collected from 460 CCTAs performed over a 3-month period at eight French hospitals. CCTAs (∼50 per centre) were performed using the routine protocols of the centres, and 64- to 320-detector CT scanners. ECG gating was prospective (n = 199) or retrospective (n = 261). The large gap in dose between these two modes required to propose specific DRLs: 26 and 44 mGy for CTDIvol, and 370 and 970 mGy cm for DLP, respectively. This study confirms the large variability in patient doses during CCTA and underlines the need for the optimisation of cardiac acquisition protocols. Availability of national DRLs should be mandatory in this setting.

No-carrier-added regioselective preparation of 6-[18F]fluoro-L-dopa.

This paper describes the preparation of 6-[18F]fluoro-L-dopa by a no-carrier-added method based on the nucleophilic displacement of nitro groups of two commercially available substrates, 3,4-dimethoxy-2-nitrobenzaldehyde (nitroveratraldehyde) and 6-nitropiperonal. Fluorination was conducted in DMSO with fluorine-18 (18F) in the presence of the aminopolyether Kryptofix 222 and potassium carbonate. The condensation of the fluorinated aldehydes with phenyloxazolone and the subsequent hydrolysis with HI/P yield, after purification by HPLC, only the 6-(D, L) isomers. The racemic mixture (50/50) was resolved on an analytical scale chiral column. The method, which requires 100 min (EOB) to complete, produces 6-[18F]fluoro-L-dopa with a decay-corrected radiochemical yield of 10%, an enantiomeric purity greater than 99%, and a specific activity of 1.2 Ci/mumole.

Fluorine-18-altanserin: a radioligand for the study of serotonin receptors with PET: radiolabeling and in vivo biologic behavior in rats.

No-carrier-added [18F]altanserin was synthesized by nucleophilic substitution of the corresponding nitro compound with [18F]fluoride in the presence of kryptofix 222 and K2CO3. After purification by preparative HPLC, [18F]altanserin was produced in less than 2 hr with a radiochemical yield of 10% (EOS) and a specific activity of 0.8-1.3 Ci/mumol. In rats, the tracer localized rapidly in the whole brain (0.5% ID/g organ) with a high binding to the frontal cortex. The frontal cortex/cerebellum ratio increased with time and reached a plateau of 11 at 2 hr postinjection. This uptake in S2 receptor regions was saturable and could be blocked by pretreatment with various S2 antagonists. This radiopharmaceutical appears to be more selective for S2 receptor sites than other ligands available today and allows the study of S2 receptors under in vivo conditions.

Thrombus in a normal sinus of Valsalva: angiographic, multiplane transoesophageal echocardiographic, and surgical findings.

A large intraluminal thrombus within an otherwise normal sinus of Valsalva was diagnosed in a 41 year old man who was investigated for myocardial infarction. The thrombus was suspected by aortic root injection, confirmed by transoesophageal echocardiography, and treated surgically.

Resistance to aspirin in vitro is associated with increased platelet sensitivity to adenosine diphosphate.

BACKGROUND: Platelet activation plays an important role in arterial thrombosis and the widespread use of aspirin has reduced major events by 25% in the secondary prevention of cardiovascular diseases. However, it appears that aspirin antiplatelet effect is not uniform and 8-45% of the population are, in vitro, aspirin resistant, and it is well recognized that platelets can be activated by pathways that are not blocked by aspirin, such as adenosine diphosphate (ADP). OBJECTIVES: To investigate whether aspirin-resistant patients have a modified sensitivity to ADP-induced platelet activation MATERIALS AND METHODS: Seventy-two patients were enrolled. Platelet function was measured by the PFA-100(R) analyser; platelet GP IIb-IIIa activation by ADP 10 micro M was assessed by flow cytometry using PAC-1 MoAb. RESULTS: Using a collagen/epinephrine coated cartridge on the PFA-100(R), the prevalence of aspirin resistance was 29.2% (n=21). For aspirin-resistant patients, the collagen/ADP coated cartridge showed a closure time significantly shorter (p=0.004) compared to the sensitive and control groups. Platelets from aspirin-resistant patients bound PAC-1 significantly more (p=0.03) than the aspirin-sensitive patients and controls when activated with 10 micro M ADP. CONCLUSIONS: Platelets from aspirin-resistant patients appear to be more sensitive and activable by ADP. This hypersensitivity could provide a possible explanation for the so-called aspirin resistance, and this could justify therapeutic improvement with alternative antiplatelet agents.

Resistance to aspirin in vitro at rest and during exercise in patients with angiographically proven coronary artery disease.

BACKGROUND: Acetylsalicylic acid, or aspirin, is widely used in secondary prevention of coronary artery diseases, but the inhibition of platelet aggregation is not uniform in all individuals. OBJECTIVE: To investigate the prevalence of aspirin resistance at rest and during exercise in coronary artery disease patients. MATERIALS AND METHODS: Fifty patients with stable coronary artery disease were prospectively studied. All patients received aspirin (75-300 mg/day for >1 month) and no other antiplatelet therapy. Aspirin resistance was studied, at rest and immediately after a stress test, using the standardized platelet function analyzer (PFA-100(R), Dade-Behring). Aspirin resistance was defined as a normal collagen/epinephrine closure time (<186 s). RESULTS: Ten patients (20%) were aspirin-resistant at rest. Out of the 40 patients who were aspirin-sensitive at rest, 9 (22%) were aspirin-resistant immediately after the exercise stress test. There were no differences in aspirin sensitivity regarding gender, age, diabetes, hypertension, dyslipidemia, platelet count, medical treatment or number of the coronary arteries involved. CONCLUSIONS: Aspirin resistance is detected, at rest, in 20% of our patients with stable coronary artery disease. Aspirin treatment does not seem to protect against exercise-induced platelet activation in 22% of such patients, despite aspirin sensitivity at rest.

Synthesis and biodistribution of [5-131I]iodotropapride: a potential D2 dopamine receptor imaging agent.

[5-131I]Iodotropapride is a benzamidic compound which displays high affinity and selectivity for dopaminergic receptors. It was prepared from the corresponding brominated compound by a nucleophilic substitution with [131I]iodine (t1/2 = 8.02 days, E gamma = 364 keV) based on the use of Cu(I) as catalyst and high specific activity of [131I]NaI. After i.v. injection in rats the tracer crosses the blood-brain barrier (0.42 +/- 0.06% of injected dose in the total brain) and demonstrates a high affinity binding to the striatum. The striatum-to-cerebellum ratio increases with time and reaches values of 9 and 22 at 30 and 120 min after injection, respectively. This specific uptake in the striatum is saturable and can be blocked by pretreatment with different D2 antagonists. When labeled with 123I (t1/2 = 13 h, E1 = 159 keV), the corresponding [123I]iodotropapride may be useful for the investigation of the D2 dopamine receptors in humans with single photon emission computer tomography (SPECT).

Perforated aneurysm of the anterior mitral leaflet: late assessment with transesophageal echocardiography.

We present a case study of a 54-year-old patient with a perforated aneurysm of the anterior mitral valve leaflet, diagnosed 13 years after an episode of bacterial endocarditis by transesophageal echocardiography. This report illustrates the superiority of transesophageal echocardiography in the diagnosis and management of valvular endocarditis.

Nomogram for Doppler echocardiographic assessment of mitral stenosis in atrial fibrillation.

Non-invasive assessment of the stenotic mitral valve area is often difficult when the mitral stenosis is associated with atrial fibrillation. In this study, 16 patients with mitral stenosis and atrial fibrillation were evaluated by transthoracic Doppler echocardiography. The mitral valve area calculated by the pressure half-time method was 1.65 +/- 0.73 cm2. The enddiastolic mitral gradient was obtained from the enddiastolic forward mitral flow velocity by application of the simplified Bernoulli equation. For each patient there was a linear relationship between the enddiastolic mitral gradient and the corresponding RR interval. The slope and intercept of this relationship were significantly correlated with the mitral valve area. From the regression equations describing these correlations we established a nomogram ascertaining mitral valve area from enddiastolic mitral gradient and corresponding heart rate. This nomogram was helpful in the non-invasive assessment of stenotic mitral valve area in the presence of atrial fibrillation.

[Aspirin resistance 2003: a review of the literature]. / Actualités sur la résistance à l'aspirine en 2003.

Despite the development of new molecules, aspirin remains a mainstay of the antiplatelet therapy, indispensable for the secondary prevention of cardiovascular events. The therapeutic used is based on the platelet aggregation inhibition induced by aspirin. The concept of aspirin resistance corresponds to a total or almost total absence of the platelet aggregation inhibition generally observed in vitro under aspirin. The frequency of this resistance depends on the platelet aggregation test used and the population studied. In a population with stable coronary disease treated in the long term with 160 to 325 mg of aspirin daily, 8 to 35% of patients are non-responders. Many hypothesis on the mechanisms of the lack of antiplatelet effect of aspirin are under investigation. The clinical implication of the in vitro antiplatelet effect resistance of aspirin has recently been evidenced by a relative risk of cardiovascular events at two years at 3. This would support an individual adaptation of the anti-platelet therapy.

[Physiopathology of myocardial infarction: the acute coronary occlusion]. / Physiopathologie de l'infarctus du myocarde: l'occlusion coronaire aiguë.

Rupture of the atheromatous plaque, thrombosis and local vasoconstriction are involved in the genesis of acute myocardial infarction. The vulnerability of the plaque depends on its histological structure. Its fragility is related to the size of the lipid core, the thinness of the fibrous capsule and the inflammatory reaction. External aggression favourites rupture. This triggers both thrombogenesis by bringing the blood cells into contact with thrombogenic subendothelial factors and local vasoconstriction due to endothelial dysfunction. Although rupture of the plaque is an unpredictable event, there is a circadian variability the highest incidence of infarction being between 6 a.m. and midday. Comprehension of the physiopathology of myocardial infarction has opened up new therapeutic approaches which should reduce the incidence of plaque rupture. Prevention is based on stabilisation of the plaque by dietary hygiene, lipid-lowering drugs and, maybe, in the future, by local application of antisense oligonucleotides. Finally, anti-aggregant therapy (aspirin or anti-GIIb-IIIa) could prevent the formation or extension of the thrombus.

[Tissue characterization by study of myocardial response to ultrasound. Review of the literature and perspectives]. / Caractérisation tissulaire par étude de réponse du myocarde aux ultrasons. Revue de la littérature et perspectives.

Echocardiography is a routine daily cardiological investigation. Recent technological developments suggest that it may become possible to quantify myocardial texture and thereby achieve histological and functional definitions of cardiac diseases. Two approaches are under evaluation: "videodensitometry" uses tools of statistical quantification from the echocardiographic image; more recently, analysis of the radiofrequency signal has been proposed. This is based on direct exploitation of a continuous signal at the transducer head of wide dynamic range containing all the information received by the piezo-electric crystals. These two approaches have given encouraging preliminary results in the recognition of different myocardial hypertrophic reactions, in diabetic cardiac disease and in the identification of myocardial viability. Despite the many remaining problems, the perspectives are promising and a new field of echocardiography should see the light of day.

[Myocardial infarction by complete thrombosis of the left main coronary artery: emergency treatment with angioplasty with implantation of a coronary stent and follow-up at one year: a case report]. / Infarctus par thrombose complète du tronc commun coronaire gauche: traitement en urgence par angioplastie avec pose de prothèse endocoronaire et suivi à 1 an. A propos d'un cas.

Acute occlusion of the left main coronary artery is usually responsible for cardiogenic shock, severe arrhythmias or sudden death. Despite the widespread use of emergency coronary angiography in acute myocardial infarction, occlusion of the left main coronary artery is rarely observed and its treatment remains controversial. The authors report the case of a young man with a previous history of radiotherapy for Hodgkin's disease, admitted for acute myocardial infarction due to complete thrombosis of the left main coronary artery treated as an emergency by percutaneous transluminal angioplasty and implantation of a Palmaz Schatz stent. There were no complications of the procedure and the patient was asymptomatic one year later.

[Ultrasonic myocardial characterization. Application of an original method of acoustic quantification to analysis of healthy and hypertrophic interventricular septal myocardium]. / Caractérisation myocardique en échographie. Application d'une méthode originale de quantification acoustique à l'analyse du septum interventriculaire de myocardes sains ou hypertrophiques.

Echocardiography does not provide objective tissue characterisation of sonified tissues. A recent advance has been the introduction of the radiofrequency signal. At present, its exploitation remains a research tool. The required material for quantification is still insufficiently robust and discriminative. The indices derived from histograms of grey scales are calculated by the majority of workers for regions of interest manually positioned in the image. This statistical method allows analysis of the average grey level but not of the architecture of the tissue examined. Tissue characterisation is, therefore, only a potential feature of echocardiography. The authors' approach consists in developing software applied to digital signal provided by the echograph and not directly by the transducer, as in the research based on the use of radiofrequency signals. This software allows characterisation of the texture by two statistical methods applied to signal processing: the histograms of the grey scales, the matrix of co-occurrence (assessing the make-up of the different grey scales in the region of interest). This tool of tissue characterisation is presented here in the studies of the interventricular septum in the parasternal long axis view. Two populations, one with healthy myocardium and the other with myocardial hypertrophy, have been studied. These two populations are differentiated in a significant manner by their respective values of parameters of myocardial texture characterisation in early diastole. Despite a number of methodological problems, this study confirms the hopes that it will be possible in the near future to obtain a quantitative "histological" definition of tissues by echocardiography.