Preferential dilation of recipient coronary arteries of the collateral circulation by intracoronary administration of nitroglycerin.
OBJECTIVE
The purpose of this study was to test the hypothesis that the sensitivity to nitroglycerin of collateral vessels and recipient arteries is greater than that of donor arteries of the collateral circulation.


BACKGROUND
The collateral circulation responds vigorously to nitroglycerin. However, the mechanisms of the efficacy of nitroglycerin for improving collateral circulation are not fully elucidated.


METHODS
The diameter of donor and recipient arteries of the collateral circulation was measured with a computer-assisted analysis system in eight patients with well developed collateral vessels. Coronary angiography was repeated before and after the intracoronary injection of 50 micrograms of nitroglycerin.


RESULTS
After nitroglycerin, the mean diameter +/- SD of donor arteries increased to 1.61 +/- 0.53 from 1.29 +/- 0.39 mm (p < 0.01), whereas the diameter of recipient arteries increased to 1.59 +/- 0.50 from 1.10 +/- 0.49 mm (p < 0.01). The change in the diameter of recipient arteries was significantly greater than that of donor arteries (52.3 +/- 24.6% vs. 24.7 +/- 11.5%, p < 0.05). These changes induced by the intracoronary injection of nitroglycerin were accompanied by a decrease in pacing-induced ST segment depression (0.16 +/- 0.06 to 0.06 +/- 0.04 mV, p < 0.01), suggesting increased flow reserve through collateral channels.


CONCLUSIONS
These findings indicate that the sensitivity to nitroglycerin of recipient arteries of the collateral circulation is significantly greater than that of donor arteries. This observation may explain the strong response of the collateral circulation to nitroglycerin in patients with functionally significant collateral channels.
Fujita
M
M
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Yamanishi
K
K
Inoko
M
M
Miwa
K
K
D000368:Aged; D003097:Collateral Circulation / Q000187:drug effects; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology; D003331:Coronary Vessels / Q000187:drug effects* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007269:Injections, Intra-Arterial; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage / Q000627:therapeutic use*; D014664:Vasodilation / Q000187:drug effects*
D005996:Nitroglycerin