[Validation of quantitative parameters of paraprosthetic mitral valve regurgitation of the zone of convergence by transthoracic echocardiography]. / Validation de paramètres quantitatifs dans l'évaluation des insuffisances mitrales paraprothétiques en échocardiographie transthoracique par étude de la zone de convergence.

The study of the convergence zone by echocardiography is a validated method of quantification of native valve mitral regurgitation. However, there is little data concerning its applications to paraprosthetic mitral regurgitation. The aim of this study was to evaluate the method in this indication. Thirty consecutive patients (21 mechanical and 9 bioprostheses) with paraprosthetic mitral regurgitation quantified by transoesophageal echocardiography were included: 4 mild, 13 moderate and 13 severe. The regurgitant volume RV) and the regurgitant surface area (RSA) were calculated by the following formulae: RV = 2 pi.r2.Va.t.alpha/180 and RSA = RV/VTI (r: mid systolic radius of the convergence zone, Va: aliasing velocity, t: regurgitation time, alpha/180: the angular correction due to parietal stress, VTI: velocity time integral of the regurgitant flow). The feasibility of the calculation of the RV and RSA was 93 and 63% respectively. There was a statistically significant correlation between the RV and transoesophageal echocardiography (r: 0.85, p < 0.001), between RSA and transoesophageal echocardiography (r: 0.67, p < 0.05) and between RV and RSA (r: 0.95, p < 0.001). When severe paraprosthetic regurgitation was defined by a RV greater than 60 ml and RSA greater than 40 mm2, the concordance between RV, RSA and transoesophageal echocardiography was 75% and 74% respectively. Therefore, the study of the convergence zone provides an accurate evaluation of paraprosthetic mitral regurgitation by transthoracic echocardiography.

[Acute complications of coronary angioplasty: prevention and management]. / Complications aiguës de l'angioplastie coronaire: prévention et prise en charge.

The immediate results of transluminal coronary angioplasty (TCA) have improved considerably during recent years. Balloon dilatation of the arterial stenosis is the basis of this technique of revascularisation but new tools may be used to treat specific lesions. Coronary occlusion is the most feared complication of TCA. It may cause myocardial infarction or death of the patient. It is usually secondary to dissection and/or thrombus of the artery. The implantation of a stent successfully treats most cases of dissection. New anti-platelet (GP IIb/IIIa) drugs seem to be very effective in the prevention and treatment of the thrombosis. The systematic use of ticlopidine limits the risk of stent occlusion. Improved features enable satisfactory implantation of stents in the majority of cases. In some patients, the clinical consequences of occlusion may be limited by vascular bypass techniques, especially intra-aortic balloon pumping. In other cases, emergency coronary bypass surgery may be necessary. When TCA is considered to be a very high risk procedure, effective surgical cover is essential.