Background The 5-year cardiac mortality rate has been reported to be more than 50% in patients with left main coronary artery (LMCA) stenosis. The purpose of this study was to visualize the LMCA using intravascular ultrasound in patients who undergo interventions of the left anterior descending coronary artery (LAD). This was done in order to see the incidence and severity of plaque formation in the LMCA in patients with severe lAD stenosis, and to address if scanning LMCA is able to rule out lAD significant stenosis or vice versa. Methods A total of 293 patients with intervention of the LAD stenosis were examined with intravascular ultrasound(IVUS). The images of 278 patients were suitable for analysis. Results Fifty-three (19%) were found to have angiographic lumen reduction in the LMCA ranging from 11% to 35% (19 ± 8%). Sixty-one patients were found to have native calcification in the LMCA. Atherosclerotic plaques in LMCA were detected in 211/278 (76%) patients, of which 164/211 (78%) were eccentric, and 51/211 (24%) had calcium deposit. The cross-sectional plaque area ranged from 1.5 mm2 to 21 mm2 (8.4 ± 4.7 mm2 ). Area of stenosis was 34 ± 14 % (8-66 % ) and diameter of stenosis was 21 ± 8% ( 7-42% ). A weak relationship concerning severity of stenosis between LAD stenosis and LMCA stenosis was found in the 59 patients with pre-interventional IVUS examinations ( r = 0.47, P ＜ 0.05 ). Condusions LMCA is frequently involved with atherosclerotic lesions in patients with severe LAD stenosis. A weak relationship does exist concerning the severity of stenosis between lAD and LMCA. However, IVUS for LMCA lesion is not able to rule out LAD stenosis.

BACKGROUNDThe purpose of this study was to assess the morphological changes and physiological function of coronary arteries in patients presenting with chest pain but having normal coronary angiograms, using intravascular ultrasound imaging (IVUS) and intracoronary Doppler (ICD) flow measurements, in order to elucidate the mechanism of syndrome X.

METHODSA total of 126 patients [67 males, 59 females, mean age (53.1 +/- 13.0) years] who experienced chest pain but had normal coronary angiograms were included in this study. ICD flow measurements of the left anterior descending coronary artery (LAD) were performed using a Cardiometrics FloMap II system. Coronary flow velocity reserve (CFVR) was defined as the ratio of the average peak velocity during hyperemia to that at baseline, induced by an intracoronary bolus injection of 18 microg adenosine. A 3.2F or 2.9 F 30 MHz mechanical rotating ultrasound catheter (CVIS, Boston Scientific) or a 3.0 F 20 MHz electronic ultrasound catheter (Endosonics) was used for IVUS.

RESULTSThe mean CFVR value of the LAD was 2.71 +/- 0.74. Reduction of CFVR (< 3.0) was found in 82 of 126 (65.1%) patients. IVUS images of the LAD were available for 109 patients. Plaque formation was detected in 76/109 (69.7%) patients. Based on the presence or absence of plaque formation as well as the reduction or non-reduction of CFVR, patients were divided into four groups: Group I (n = 10), normal IVUS findings and normal CFVR; Group II (n = 23), normal IVUS findings with reduction in CFVR; Group III (n = 29), IVUS evidence of plaque formation but normal CFVR; and Group IV (n = 47), IVUS evidence of plaque formation with reduction in CFVR.

CONCLUSIONThis study shows the important clinical value of a combination of IVUS and ICD in diagnosing patients with angiographically normal coronary arteries. Only 10% of patients studied (Group I) were found to be truly free of coronary disease, while 20% of patients (Group II) would be diagnosed as suffering from syndrome X.

Adult ; Aged ; Coronary Angiography ; Coronary Circulation ; Female ; Humans ; Laser-Doppler Flowmetry ; Male ; Microvascular Angina ; diagnosis ; physiopathology ; Middle Aged ; Ultrasonography, Interventional