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Biomedical subjects

N Danchin

Publications and source records attributed to N Danchin.

297 records · Page 17Linked to original sources
PubMedDate not supplied

[Intracoronary radiotherapy (brachytherapy) for treatment of restenosis].

UNLABELLED: RESTENOSIS AFTER CORONARY ANGIOPLASTY: Restenosis after coronary angioplasty remains a common clinical problem. Even after the advent of stenting, the rate of restenosis is still to the order of 20% or even higher in certain patient subgroups. Treatment is difficult, particularly in case of diffuse restenosis within stent lumens. POTENTIAL CONTRIBUTION OF BRACHYTHERAPY: After stent implantation, restenosis is generally due to excessive intimal proliferation producing a "benign tumor" formation that progressively obstructs the arterial lumen. Endocoronary curietherapy has been proposed for its "antiproliferative" effect. SYSTEMS USED: Two radiation sources are used: gamma emitters with powerful tissue penetration properties, and beta emitters which exhibit less tissue penetration. Radioprotection is a greater problem with gamma emitters but dosimetry is more difficult to control with beta emitters. In clinical practice, the sources are placed close to the target site via conventional percutaneous catheterization and are employed as a complement to standard angioplasty used to destroy the stenosis. Endocoronary brachytherapy requires close collaboration between the interventional cardiologist and the radiotherapist. CLINICAL TRIALS: After the preliminary feasibility studies, several randomized trials have assessed the contribution of brachytherapy in the prevention of restenosis. Using gamma emitters (192Ir), the SCRIPPS, WRIST and GAMMA-1 studies demonstrated good immediate safety and a real effect on restenosis with 50% reduction. Inversely, groups of treated patients have a higher rate of severe complications (death and infarction) related to late acute coronary thrombosis after interruption of antiplatelet therapy combining ticlopidin and aspirin. These complications result from the frequent introduction of stents during angioplasty procedures and by delayed endothelialization of the stents leaving a starting point for thrombosis formation longer than usual. The same type of complications have been observed with beta brachytherapy in the PREVENT trial, while in the START trial that used the 90Sr/y source in 476 patients, severe events were not more frequent in the irradiated group. In the latest trial, the frequency of new stent implantations was lower (21%) and antiplatelet treatment was maintained longer. Finally, the rate of restenosis was significantly lower (29% versus 45%). PRACTICAL APPLICATIONS: Current data confirm the efficacy of endocoronary brachytherapy to limit intimal proliferation after angioplasty and reduce the rate of restenosis. The question of safety remains open, with the potential risk of late coronary thrombosis; no long-term data (more than 5 years) are available. It is undoubtedly too early to propose routine use of brachytherapy, excepting perhaps cases where interventional cardiology raises particularly difficult problems, for example in case of diffuse restenosis within an endoprosthesis.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

[Contribution of centralized reading of intima media thickness in an IMMEDIAT study conducted in hypertensive patients followed up in general medicine].

OBJECTIVE: To compare the results of two readings of Intima Media thickness (EIM): one performed during measurement by the cardiologist, the other by a technician in a reading unit. To evaluate the consequences of these readings on the principal criterion of a study conducted into cardiovascular risk (RCV) for hypertensives followed up in ordinary medical practice. METHODS: The EIM was measured in 991 hypertensives with the aid of the M'Ath program by cardiologists specially trained in the technique, within the framework of a study aimed at evaluating the RCV according to the WHO/ISH classification. The re-reading of source data by a reference centre was performed with the same program. RESULTS: The analysis was performed in 973 patients after eliminating duplicates and missing values (2%). The average cardiologist value of EIM was 0.761 +/- 0.168 mm, after centralised reading it was 0.743 +/- 0.128 mm. The difference between the measurements was -0.020 +/- 0.150 (p < 0.0001). According to the OMS/ISH classification, the presence of a vascular condition categorizes a hypertensive as being at "high risk" of a cardiovascular complication occurring. The calculation of RCV was performed by taking a value of EIM > 0.7 mm and/or presence of a plaque to define a vascular condition. The appreciation of risk was identical for the subjects at low risk and at very high risk. There was a shift from medium risk towards high risk: General Medicine 15%, Cardio 49%, after re-reading 68%. CONCLUSION: Despite the simplicity and the good inter observer reproducibility of the measurement of EIM by the M'Ath program, centralization of the reading is recommended during clinical trials.

Adult↗
PubMedDate not supplied

[Screening for a frequent cardiac disorder: mitral valve prolapse].

Mitral valve prolapse (MVP) screening using bidimensional echocardiography was performed on 171 healthy subjects from Lorraine of both sexes, aged 20 to 60 years. Six men and seven women presented this valvular disease. In the Lorraine population, the estimated prevalence of MVP was 7.6% (95% confidence interval: 3.6-11.6%). In this study, only seven cases of MVP had a cardiac auscultation suggestive of MVP. As compared with echocardiography, clinical screening of MVP had a low validity (sensibility 54%, specificity 69%) and a poor positive predictive value (12.5%). Because MVP has severe complications, and because clinical screening has a low performance, a strategy of screening with bidimensional echocardiography could be interesting.

Adult↗
PubMedDate not supplied

[Infarction of the right ventricle. Contribution of two-dimensional echocardiography].

This study, based on 39 cases, confirms the value of two-dimensional echocardiography in the diagnosis of right ventricular infarction during the acute phase. This diagnosis is confirmed by the presence of abnormalities of the segmental kinetics always present in the inferior wall and less frequently in the anterior wall. The inferior part of the septum is affected in two thirds of cases. Right ventricular dilation is frequently observed, but is not constant. Two-dimensional echocardiography has a diagnostic sensitivity similar to that of isotope ventriculography, but greater than that of haemodynamic investigations. Finally, apart from the easy demonstration of complications (tricuspid incompetence, septal rupture, intracardiac thrombosis), two dimensional echocardiography can be used to evaluate right ventricular function.

Cardiomegaly↗
PubMedDate not supplied

[Value of bidimensional echocardiography in the diagnosis of early mechanical complications of myocardial infarction].

Thirteen patients with myocardial infarction were investigated with two-dimensional echocardiography because of the appearance of signs of cardio-circulatory failure associated with a systolic murmur during the first 15 days following the infarct. The precise diagnosis was obtained by surgical or autopsy examination in 11 cases and by haemodynamic investigations in 2 cases. These mechanical complications were: 8 septal ruptures and 5 cases of acute mitral incompetence, due to papillary rupture in 2 cases and to papillary dysfunction in 3 cases. The 8 cases of septal rupture, complicating 6 cases of anterior infarct and 2 cases of diaphragmatic infarct, were diagnosed by 2-D echocardiography, which revealed 3 apical perforations (one of which was only visible via a sub-costal approach), 3 superior perforations or lacerations, 2 inferior perforations in the middle or the base of the septum; all visible in an apical view of the 4 cavities. The injection of ultrasonic contrast in 4 patients demonstrated negative lavage, which confirmed the diagnosis, in one case, even before the perforation could be visualised. The 2 cases of ruptured papillary muscles were visualised directly on the 2-D echocardiography. However, only one of the three cases of papillary muscle dysfunction was diagnosed by echocardiography. 2-D echocardiography has an important place in the investigation of complicated myocardial infarction, not only as a means of diagnosing ruptures of the septum or papillary muscles, but also to evaluate the deterioration in left ventricular contractile function, which enabled surgical repair without left haemodynamic investigations, in two cases.

Acute Disease↗