Balloon dilatation of the stenosed aortic valve: how does it work? Why does it fail?

The hemodynamic changes that may occur in patients undergoing aortic balloon valvuloplasty were examined in the circulatory model. Four conclusions were reached. (1) Significant transvalvular pressure gradients appear only if the orifice is severely narrowed. (2) The magnitude of this gradient is highly flow dependent. (3) At critical narrowings, minute alterations in orifice size may induce most significant changes in the transvalvular gradient. (4) In low flow states significant gradients appear only if the stenosis is extreme. In patients with aortic stenosis, especially those with failing hearts and low cardiac output, the pressure gradient may be effectively decreased by minimal dilatation of the aortic orifice. These patients, however, remain in jeopardy because recurrent narrowing may cause a gradient incompatible with life.

Balloon valvuloplasty in calcified aortic stenosis: a cause for caution and alarm.

Balloon dilation by the percutaneous route has recently been recommended as an alternative to surgical intervention in the management of calcified aortic valvular stenosis. To investigate the validity of balloon valvuloplasty, this procedure was carried out in the operating room under direct vision in 30 patients just prior to excision and replacement of the ossified aortic valve. Changes induced by balloon dilation were evaluated by visual inspection as well as by geometric measurements. By visual observation, balloon valvuloplasty did not have a detectable impact on the valvular anatomy in about 19 of the patients and induced enlargement of the functional aortic orifice judged as "minimal" or "moderate" in only 11. In no patient was there a substantial increase in the functional orifice size. These findings were supported by geometrical measurements. Therefore, we believe that the virtues of this procedure have been grossly overstated by its proponents and that it should be offered only to patients who present a truly forbidding risk by standards of modern surgery.

Limited value of balloon dilatation in calcified aortic stenosis in adults: direct observations during open heart surgery.

Percutaneous balloon dilatation was recently recommended as a treatment for management of calcified aortic valvular stenosis. This procedure was initially reserved for patients who were not considered surgical candidates; it is now regarded by some as an acceptable alternative for valve replacement. To investigate the validity of this postulate, balloon valvuloplasty was performed under direct vision in the operating room in 16 patients just before excision and replacement of their ossified aortic valve. Changes after valvuloplasty were evaluated by inspection as well as by geometric measurements. The authors found that balloon valvuloplasty did not make a detectable impact on valvular anatomy in about two-thirds of the patients and induced enlargement of the functional aortic orifice judged as "minimal" or "moderate" in one-third of the cases. In no patient was there significant increase in the functional orifice size. Other investigators have shown that hemodynamic and clinical improvement may be induced in some patients by small increases in the aortic orifice; based on the observations herein, such an improvement, if it occurs at all, would be short-lasting; the procedure should be offered only to those who present truly prohibitive risk by standards of modern surgery.