Quantitative Angiographic Analysis of PTCA-Induced Coronary Vasoconstriction in Single-Vessel Coronary Artery Disease

Abstract

Quantitative coronary angiography was applied to investigate the degree and extent of coronary vasoconstriction following percutaneous transluminal coronary angioplasty (PTCA) in single-vessel disease of segments distal to the PTCA site (n=46) and of control segments in nonmanipulated vessels (n=33) before PTCA, 15 minutes after PTCA, and again 10 minutes after 10 mg sublingual isosonbide dinitrate (ISDN) in 46 patients receiving neither nitrates nor calcium channel blockers prior to PTCA. Furthermore, the degree of coronary vasoconstriction was compared with ergonovine-induced vasocon striction (n=8) as well as in patients with and without restenosis during follow-up angiography 4 months later. PTCA induced a moderate, but significant, vasoconstriction in both distal and control segments, with a reduction in coronary diameter from 2.34 ±0.58 to 2.26 ±0.55 mm (P=0.011) and from 2.70 ±0.62 to 2.60 ±0.65 mm (P=0.004), respectively. No corre lation between the degree of vasoconstriction on the one side and lesion severity and PTCA-induced mechanical stretch, judged by the sum of the products of inflation pressure and time, on the other side was found. Vasoconstriction was within the limits achiev able with the potent vasocontrictor ergonovine and did not differ in patients with or without restenosis. ISDN led to a significant vasodilatation in all segments. In conclusion, coronary vasoconstriction following PTCA is present in the coronary tree in a rather diffuse way. It is not associated with stenosis severity or PTCA-induced mechanical stretch, suggesting a complex underlying mechanism. ISDN-reversible vaso constriction was within the limits achievable with ergonovine and did not differ with regard to restenosis.