Hypersensitivity of human coronary segments to ergonovine 6 months after injury by coronary angioplasty: a quantitative angiographic study in consecutive patients undergoing single-vessel angioplasty.

OBJECTIVE: Multiple studies have been designed to analyse restenosis angiographically but few have studied the vasoreactivity of coronary segments subjected to angioplasty a few months before. In the present study we analysed, with use of quantitative angiography, the vasoreactivity of previously dilated segments to graded doses of ergonovine and of isosorbide dinitrate. PATIENTS: Fifty consecutive patients undergoing follow-up angiography 6 months after a single coronary angioplasty procedure were studied.
RESULTS: The vasoconstrictor response at dilated segments (-19.3 +/- 3.0%) was significantly greater than at control proximal and distal sites in dilated (-7.3 +/- 1.1%, -11.0 +/- 2.9%) and non-dilated (-9.1 +/- 1.3%, -8.3 +/- 2.2%) vessels for the lowest dose of ergonovine (100 micrograms). The constrictor response to 100 micrograms ergonovine (-20.2 +/- 5.3%) at restenosed segments (> 50% stenosis, n = 18) was similar to that (-18.8 +/- 3.8%) at non-restenosed sites (n = 32). In contrast, the degree of constrictor response was similar in all segments including dilated segments for the highest dose of ergonovine used. All segments dilated significantly after intracoronary injection of isosorbide dinitrate.
CONCLUSION: Our results demonstrate hypersensitivity of the dilated site to ergonovine 6 months after angioplasty at both restenosed and non-restenosed sites. This response may reflect partial dysfunction of endothelium that has regenerated after injury or hypersensitivity of vascular smooth muscle cells at the site of arterial injury.