QUANTITATIVE ANGIOGRAPHIC ANALYSIS OF PTCA-INDUCED CORONARY VASOCONSTRICTION IN SINGLE-VESSEL CORONARY-ARTERY DISEASE

Quantitative coronary angiography was applied to investigate the degre e and extent of coronary vasoconstriction following percutaneous trans luminal coronary angioplasty (PTCA) in single-vessel disease of segmen ts distal to the PTCA site (n=46) and of control segments in nonmanipu lated vessels (n=33) before PTCA, 15 minutes after PTCA, and again 10 minutes after 10 mg sublingual isosonbide dinitrate (ISDN) in 46 patie nts receiving neither nitrates nor calcium channel blockers prior to P TCA. Furthermore, the degree of coronary vasoconstriction was compared with ergonovine-induced vasoconstriction (n=8) as well as in patients with and without restenosis during follow-up angiography 4 months lat er. PTCA induced a moderate, but significant, vasoconstriction in both distal and control segments, with a reduction in coronary diameter fr om 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 correlation between the de gree of vasoconstriction on the one side and lesion severity and PTCA- induced mechanical stretch, judged by the sum of the products of infla tion pressure and time, on the other side was found. Vasoconstriction was within the limits achievable with the potent vasocontrictor ergono vine and did not differ in patients with or without restenosis. ISDN l ed to a significant vasodilatation in all segments. In conclusion, cor onary vasoconstriction following PTCA is present in the coronary tree in a rather diffuse way. It is not associated with stenosis severity o r PTCA-induced mechanical stretch, suggesting a complex underlying mec hanism. ISDN-reversible vasoconstriction was within the limits achieva ble with ergonovine and did not differ with regard to restenosis.