The persistent enigma of percutaneous angioplasty.

In summary, while both the short-term and long-term success of PTCA is undeniable in most patients, the basis for this success remains an enigma. Admittedly, simply because "plaque fractures" and "dissection clefts" have been observed to occur as the result of artifact, one cannot exclude the possibility that the success of PTCA may be related to these lesions. Alternatively, the fact that improved vessel patency is frequently observed angiographically and pathologically in the absence of such lesions precludes firm assurance that such lesions are the basis for a successful dilatation. Identification of the mechanism responsible for the success of PTCA is more than a matter of simple curiosity: improved understanding of the basis for successful PTCA might lead to technical refinements in the procedure and allow one to better tailor the technique to individual variations in lesion morphology. Perhaps the combined use of selective, intra-vascular angioscopy at the time of PTCA will enhance our understanding of the fundamental mechanism responsible for this highly effective therapy.