Identification of syndrome X using intravascular ultrasound imaging and Doppler flow mapping

Background The 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. Methods A 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 μg adenosine. A 3.2F or 2.9F 30 MHz mechanical rotating ultrasound catheter (CVIS, Boston Scientific) or a 3.0F 20MHz electronic ultrasound catheter (Endosonics) was used for IVUS. Results The 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. Conclusion This 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.

SHORT-TERM REPRODUCIBILITY OF INTRAVASCULAR ULTRASOUND IN VIVO

We studied 24 patients (18 males, 56.1 ± 6.2 years) who underwent coronary artery angioplasty for stenosis in the left anterior descending coronary artery (LAD), using a 3.5F or 4.8F intravascular ultrasound (IVUS) catheter. The proximal

THREE-DIMENSIONAL RECONSTRUCTION OF TWODIMENSIONAL INTRAVASCULAR ULTRASOUND IMAGES

The purpose of the study is to reconstruct the coronary arteries in 3 dimension (3D) from serial intravascular ultrasound (IVUS) images generated during a pullback of IVUS catheter. Slowly pullback. real-time, cross-sectional IVUS images of 18 patients (2 with normal coronary arteries. 1 with coronary aneurysm. and 15 post PTCA) were obtained by using a 20 MHz. 3.5F IVUS catheter and recorded on video tape. A series of 90-frame consecutive IVUS images were digitized into a SUN Spare 11 workstation. Digitized data were reconstructed to 3D images with use of voxel space modeling and were generated in both sagittal and cylindrical formats. The sagittal format results in a longitudinal

OBSERVATION OF THE VENOUS SYSTEM WITH INTRAVASCULAR ULTRASOUND

Intravascular ultrasound (IVUS) offers accurate morphological assessment of arterial vasculature. Here we present a preliminary observation on venous system in vivo with IVUS, Seven superior vena cava (SVC) and eight inferior vena cava (IVC) were studied in ten individuais [M / F = 7 / 3, mean age = 60.2 ±9.6 years (39-77 years)]with a 6.2F, 20MHz catheter. The cross-sectional shape, pulsation, spontaneous echo contrast (SEC) and plaque formation were analyzed. The maximal and minimal lumen diameters (Dmax, Dmin) and the area were measured. For each measurement three different frames were analyzed and the average value was taken.