Assessment of coronary vasodilatation in response to nitroglycerin with transthoracic Doppler echocardiography.
BACKGROUND
Previous studies demonstrated impaired coronary vasodilatory response (VR) to nitroglycerin (NG) in patients with coronary atherosclerosis. We hypothesized that the effect of the NG on the coronary blood flow (CBF) is negligible compared with its effect on the epicardial coronary artery dilatation and, therefore, that CBF velocity reduction after NG can reflect the magnitude of epicardial coronary artery dilatation.


METHODS
Quantitative coronary angiography was performed at the left anterior descending coronary artery (LAD) before and after intracoronary NG (200 mug) infusion in 18 patients with normal-looking coronary angiogram. VR assessed by quantitative coronary angiography (VRangio) was defined as: (LAD diameter after NG)(2)/(LAD diameter before NG)(2). Mean values measured at the ostium and at the junction of mid and distal LAD were used in the analysis. Diastolic CBF velocity was evaluated by using a 7-MHz transducer at the distal LAD before and 3 minutes after sublingual NG. VR assessed by echocardiography (VRecho) was defined as: (mean diastolic CBF velocity before sublingual NG)/(mean diastolic CBF velocity after sublingual NG). In 11 patients, plaque burden was assessed by intravascular ultrasound and results were compared with VRangio and VRecho.


RESULTS
VRecho was found to correlate well with VRangio (r = 0.71, P = .001), and VRangio and VRecho showed significant negative correlations with plaque burden (r = -0.66, P = .03; r = -0.77, P = .005, respectively).


CONCLUSIONS
VR to NG can be evaluated noninvasively with transthoracic Doppler echocardiography.
Sohn
Dae-Won
DW
Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Chongno-Gu, Seoul, Korea. dwsohn@snu.ac.kr
Kim
Yong-Jin
YJ
Kim
Hyung-Kwan
HK
Kim
Kyung-Yi
KY
Koo
Bon-Kwon
BK
Zo
Joo-Hee
JH
Kim
Hyo-Soo
HS
Oh
Byung-Hee
BH
Park
Young-Bae
YB
Choi
Yun-Shik
YS
D001783:Blood Flow Velocity / Q000187:drug effects; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003326:Coronary Circulation / Q000187:drug effects*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects; D004452:Echocardiography / Q000379:methods*; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007261:Infusions, Intra-Arterial; D008297:Male; D005996:Nitroglycerin / Q000008:administration & dosage*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014664:Vasodilation / Q000187:drug effects*
D005996:Nitroglycerin