Experimental balloon valvuloplasty of fibrotic and calcific mitral valves.

Abstract

This study evaluated the mechanism of valvular area expansion during single-and doubleballoon valvuloplasty in fibrotic and calcific mitral valves. Special interest was focused on the morphological features of the valves treated. Mitral valves that appeared unsuitable for commissurotomy were excised in toto at the time of mitral valve replacement in 15 patients. The excised valves were mounted in a fluid-filled chamber with a window for photographic evaluation. The chamber was perfused continuously to ensure maximal valvular opening. The valve was photographed, and the orifice area was measured before and after balloon expansion. In addition, the specimens were examined macroscopically and radiographically with regard to calcium content and degree and localization of fibrosis. These data were correlated with splitting of commissures and with rupture of leaflets. Nine valves were fibrotic, and six were calcific. Dilatation was performed first with a single-balloon catheter (diameter, 2 cm) and then with a double-balloon catheter (diameter, 2 and 1.5 cm). After dilatation with one balloon, the average mitral valve area increased from 0.79 to 1.09 cm2, and with two balloons, average area increased to 1.59 cm2. The single-balloon technique caused commissural splitting in nine valves, stretching in three, partial leaflet rupture in one, and no change in two. After the double-balloon technique, commissural splitting occurred in 12 valves and three leaflets were ruptured where severe fibrosis and calcification were mainly located within the commissures. As a rule, after dilatation with the single-balloon technique, the remaining stenosis was still severe, and after dilatation with the double-balloon technique, the remaining stenosis was moderate. The results show that percutaneous mitral valvuloplasty might be successful despite severe fibrosis and calcification. In some patients, however, mitral regurgitation will probably develop because of tearing of the mitral valve leaflet. This seems to depend mainly on the distribution of advanced morphologic changes, not on their degree. (Circulation 1990;81:1005-1011 Surgical mitral commissurotomy has been a standard procedure for several decades.

Characteristics of pericardial interstitial cells and their implications in pericardial fibrocalcification

“…Calcification by hematoxylin-eosin staining was demonstrated as an amorphous aggregate of basophilic crystalline material [18]. According to previous reports [19,20], the degree of calcification was quantified as 0, no calcification; 1, mildly calcified (small isolated spots); 2, moderately calcified (multiple larger spots); and 3, heavily calcified (extensive calcification).…”

Percutaneous balloon mitral valvuloplasty: Comparison of double and single (Inoue) balloon techniques

“…It has been suggested that because the stenotic mitral orifice is oval and not circular, double balloons selforient [6] and exert maximal force laterally toward the fused commissures, resulting in superior valve opening [32,33]. This suggestion is supported by results from in vitro studies [34,35].…”

Influence of intraballoon pressure on development of severe mitral regurgitation after percutaneous transvenous mitral commissurotomy

“…The cause of severe mitral regurgitation after PTMC is almost always leaflet tear [5,9,10]. Using an in vitro model, Reifart et al found an incidence of leaflet laceration of 13% [9].…”

“…Using an in vitro model, Reifart et al found an incidence of leaflet laceration of 13% [9]. They postulated that the leaflets themselves were less resistant to rupture than the commissures.…”