Reactive hyperemia following coronary balloon angioplasty, but not dipyridamole-induced hyperemia, predicts resolution of exercise-induced ST-segment depression.
OBJECTIVE
To characterize delayed restoration of coronary blood flow following successful percutaneous transluminal coronary angioplasty (PTCA).


BACKGROUND
Delayed restoration of coronary blood flow following successful PTCA is common and likely the result of multiple factors. Temporary myocardial ischemia and dipyridamole administration both result in increased coronary blood flow, but by different mechanisms. The relationship between these phenomena and exercise-induced ST-segment depression after PTCA was investigated to determine if any correlation existed.


METHODS
Forty consecutive patients with single-vessel coronary artery disease underwent treadmill exercise testing before and after PTCA. The percentage change in coronary blood flow before and after 90 s balloon inflation was assessed. After a new steady state had been reached, dipyridamole was infused and changes in coronary blood flow were again determined. The relationship between changes in coronary blood flow and the presence of ST-segment depression during exercise testing after PTCA was determined.


RESULTS
Peak coronary blood flow induced by reactive hyperemia was significantly greater than that in the steady state after balloon inflation (48.5+/-38.8 compared with 15.1+/-13.2 ml/min, P<0.0001). Dipyridamole administration also resulted in significant increases in coronary blood flow (15.1+/-13.2 ml/min compared with 31.0+/-24.9 ml/min, P<0.0001). ST-segment depression after PTCA was significantly less than before (0.10+/-0.07 mV compared with 0.19+/-0.08 mV, P<0.001). Further, reactive hyperemia, but not dipyridamole-induced hyperemia, correlated with attenuation of exercise-induced ST-segment depression after PTCA (r=0.62, P<0.0001).


CONCLUSIONS
Reactive hyperemia following temporary coronary occlusion recreates local conditions associated with delayed resolution of myocardial ischemia following successful PTCA. Further, this phenomenon appears to be distinct from changes in coronary blood flow induced by dipyridamole.
Saihara
Keishi
K
First Department of Internal Medicine, Kagoshima University, Japan.
Hamasaki
Shuichi
S
Biro
Sadatoshi
S
Kamekou
Masahiro
M
Nakano
Fumio
F
Tsurugida
Masanori
M
Yoshitama
Takashi
T
Ishida
Sanemasa
S
Yoshikawa
Akiko
A
Kataoka
Tetsuro
T
Minagoe
Shinichi
S
Tei
Chuwa
C
D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D003327:Coronary Disease / Q000628:therapy*; D004176:Dipyridamole / Q000494:pharmacology; D005080:Exercise Test; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology; D012039:Regional Blood Flow / Q000187:drug effects
D004176:Dipyridamole