Variable responses of highly stenotic coronary arteries and collateral circulation to intracoronary injection of nitroglycerin in patients with chronic effort angina.
OBJECTIVE
To assess the direct effects of nitroglycerin on coronary and collateral circulation, 31 consecutive patients with low exercise capacity resulting from chronic effort angina but who had not suffered previous myocardial infarction were investigated.


METHODS
Rapid atrial pacing was used to induce myocardial ischemia, with the same pacing rate before and after an intracoronary injection of 50 micrograms nitroglycerin. Fifteen patients (group A) with an obstructed ischemia-related coronary artery (IRCA) (TIMI flow grade 0 or 1), were injected with nitroglycerin into a major donor artery of the well-developed collateral circulation. Sixteen patients with patent IRCAs (TIMI flow grade 2 or 3) were injected with nitroglycerin into the IRCA. These patients were subdivided according to the morphologic findings of the stenosis in the IRCA: group B, nine patients with eccentric elliptical residual lumens, and group C, seven patients with circular residual lumens.


RESULTS
In group A, 0.21 +/- 0.08 mV of pacing-induced ST-segment depression was consistently ameliorated to 0.08 +/- 0.05 mV after pretreatment with nitroglycerin (P < 0.0001). In group B, the extent of ST-segment depression was markedly improved from a basal value of 0.21 +/- 0.05 mV to 0.05 +/- 0.03 mV with nitroglycerin (P < 0.001). In contrast, in group C ST-segment depression remained unchanged despite pretreatment with nitroglycerin (0.21 +/- 0.04 mV to 0.21 +/- 0.05 mV, P = NS).


CONCLUSIONS
These results indicate that the contribution of the dynamic stenosis of the IRCA to effort angina differs greatly among patients and depends on the morphologic findings of the stenosis in the IRCA, and also that collateral circulation responds effectively to intracoronary injection of nitroglycerin in all patients with a well-developed collateral circulation.
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
M
M
Fujita
K
K
Yamanishi
K
K
Miwa
M
M
Inoko
D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000188:drug therapy*; D001794:Blood Pressure / Q000187:drug effects; D002304:Cardiac Pacing, Artificial; D002908:Chronic Disease; D003097:Collateral Circulation / Q000187:drug effects*; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects*; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology; D005996:Nitroglycerin / Q000008:administration & dosage / Q000627:therapeutic use*; D005082:Physical Exertion; D016277:Ventricular Function, Left / Q000187:drug effects; D017725:Ventricular Pressure / Q000187:drug effects
D005996:Nitroglycerin