[Percutaneous mitral commissurotomy. 5-year results]. / La commissurotomie mitrale percutanee. Resultats a 5 ans.

Long-term results of percutaneous mitral commissurotomy were evaluated in 410 patients with mean age of 31 years (18 to 68 years). 48% of patients had mean thickened leaflets, 35% had calcified valves and 17% had flexible leaflets and subvalvular apparatus. Procedure was performed with a double balloon in 57% and with Inoue's balloon in 43% patients. A good immediate results was obtained in 77% of patients. A good result was defined as a mitral valve area > or = 1.5 cm2 without mitral regurgitation. Clinical follow-up concern 378 patients. The actuarial 5 years rate were 84% in our serie, without surgery or new percutaneous mitral commissurotomy and good functional results (NYHA class I or II) were 71%. Valvular anatomy, immediate results (mitral valve area), history of mitral commissurotomy, old patients, atrial fibrillation can influence strongly the results.

[Compensatory enlargement versus chronic constriction. The two features of vascular remodelling after experimental angioplasty]. / Elargissement compensateur versus constriction chronique. Les 2 modalités du remodelage vasculaire après angioplastie expérimentale.

Considerable efforts have been made to prevent post-angioplasty restenosis targeted mainly against a pathogenesis suggesting a dominant role of hyperplasia. We and others have already shown that constrictive remodelling plays a major role in restenosis. This article evaluates not only the constrictive remodeling theory but also compensatory enlargement associated with prevention of restenosis. The present study on 33 rabbits used the following protocol. Four weeks after inducing an atherosclerotic lesion by air-dessication of a femoral artery segment and a high cholesterol diet, angioplasty was performed. The angiographic minimal luminal diameter significantly increased after angioplasty. Three to four weeks later, initial gain was significantly lost. Restenosis was quantified histologically as well as a remodelling index and a hyperplasia index. No correlations were observed between degree of stenosis and hyperplasia present at the same degree in animals with and without restenosis. On the other hand, there was a strong correlation between restenosis and constrictive remodelling, and with absence of restenosis and compensatory enlargement. Moreover, there was significant a correlation between the degree of hyperplasia and the compensatory remodelling. These data point to the double nature of remodelling: compensatory enlargement observed in animals without restenosis, and constrictive remodelling, the principal mechanism observed in animals with restenosis.

Remodelling: therapeutic opportunities.

Restenosis after angioplasty has been recently attributed to a lack of compensatory enlargement and/or chronic constrictive remodelling, rather than neointimal growth. Also, restenosis occurring after stent has been clearly related to neointimal growth. This clarification has dramatically helped in designing strategies targeted against the appropriate mechanisms. The mechanism of stent-related restenosis has been the most studied and several antiproliferative agents including gene therapy and radioactive stents have been successfully tested. Constrictive remodelling has been identified more recently and its pathophysiological mechanism remains poorly understood. Control of extracellular matrix metabolism might be an important pathway. Moreover, detection of the arteries that will 'enlarge' should avoid any preventive strategy including systematic stenting.