Left anterior descending coronary artery wall thickness measured by high-frequency transthoracic and epicardial echocardiography includes adventitia

High-frequency, 2-dimensional transthoracic echocardiography (HR-2DTTE) measurements of the left anterior descending (LAD) coronary artery wall thickness are larger than measurements obtained by intravascular ultrasound. We hypothesize that this difference is due to inclusion of the third vascular layer, which may represent adventitia by HR-2DTTE, and that this layer must be increasing in thickness with the development of atherosclerosis. We evaluated the contribution of this third layer to the wall thickness of the normal and atherosclerotic LAD artery imaged by HR-2DTTE using high-frequency epicardial echocardiography (HFEE) as the reference standard. Eighteen patients (10 men, mean age 62 years), 13 with coronary atherosclerosis and 5 with normal coronary arteries, referred for open-heart surgery, underwent preoperative HR-2DTTE evaluation of the LAD artery (SONOS 5500; 3- to 8-MHz transducer) and intraoperative HFEE of the LAD artery (SONOS 5500; 6- to 15-MHz transducer). Wall thickness was greater in patients with coronary atherosclerosis than in those with normal coronary arteries by both HR-2DTTE (1.9 +/- 0.3 vs 1.0 +/- 0.1 mm, p = <0.001) and HFEE (1.8 +/- 0.2 vs 1.0 +/- 0.2 mm, p = <0.001). On HFEE, the average intima plus media thickness was greater in patients with coronary atherosclerosis than in those with normal coronary arteries (0.78 +/- 0.3 vs 0.34 +/- 0.1 mm, p = 0.005). The average thickness of adventitia was also greater in patients with coronary atherosclerosis than in those with normal coronary arteries (0.92 +/- 0.2 vs 0.54 +/- 0.2 mm, p = 0.0005). HR-2DTTE and HFEE measurements of the wall thickness correlated well (r = 0.83 [reader 1], p <0.001; r = 0.61 [reader 2], p <0.01). A third vascular layer, which likely included adventitia, represents a significant portion of the LAD wall thickness imaged by HR-2DTTE and HFEE, and it significantly increases in thickness with the development of atherosclerosis.     

Detection of subclinical coronary atherosclerosis using two-dimensional, high-resolution transthoracic echocardiography

OBJECTIVES: We evaluated whether two-dimensional high-resolution transthoracic echocardiography (HR-2DTTE) can detect changes in arterial wall thickness and size associated with subclinical coronary artery disease (CAD). BACKGROUND: Arterial wall thickening, compensatory arterial enlargement and a preserved arterial lumen characterize subclinical atherosclerosis. Detection of these changes during the asymptomatic stage of CAD may allow early treatment and prevention of acute coronary events. METHODS: Twenty-six patients with angiographically proven CAD and 29 normal volunteers underwent HR-2DTTE evaluation of the left anterior descending coronary artery (LAD) using an ATL 5000 echograph (Advanced Technology Laboratories, Bothell, Washington) with a 4 to 7 MHz transducer. Significant (>70%) LAD stenosis was present in 15 patients (mean 82%); 11 patients did not have significant LAD stenosis (mean 26%) and represented a surrogate for subclinical LAD disease. Wall thickness, maximal luminal diameter and external diameter of the LAD were measured. RESULTS: Left anterior descending coronary artery wall thickness was larger in patients (1.9 +/- 0.4 mm) than it was in volunteers (0.9 +/- 0.1 mm, p < 0.001). The external diameter of the LAD was (6.0 +/- 1.1 mm) in patients and (3.9 +/- 0.7 mm) in volunteers (p < 0.001). Luminal diameter was 2.2 +/- 0.5 mm in patients and 2.1 +/- 0.6 mm in volunteers (p = NS). There was no difference in wall thickness (1.9 +/- 0.4 mm vs. 2.0 +/- 0.4 mm), luminal diameter (2.2 +/- 0.5 mm vs. 2.2 +/- 0.4 mm) and external diameter (5.9 +/- 1.0 mm vs. 6.2 +/- 1.2 mm) between the patients with <70% and >70% LAD stenosis. CONCLUSIONS: Left anterior descending coronary artery wall thickness and external diameter are significantly increased in patients with CAD as compared with normal subjects, and HR-2DTTE is sensitive enough to detect these differences. Wall thickness and external diameter are increased to the same extent in patients with obstructive and subclinical LAD disease.     

Comparison of high-frequency two-dimensional transthoracic echocardiography versus intravascular ultrasound for evaluation of the left anterior descending coronary artery

The purpose of this study was to evaluate the feasibility of high-frequency transthoracic echocardiography for measuring the wall thickness and luminal area of the left anterior descending coronary artery (LAD). Fifteen patients underwent simultaneous high-frequency transthoracic echocardiography and intravascular ultrasound (IVUS) examinations. There were good agreements for wall thickness (0.38 +/- 0.05 vs 0.38 +/- 0.06 mm, p = 0.0004) and luminal area (3.24 +/- 1.05 vs 3.32 +/- 1.34 mm2, p <0.0001) between high-frequency transthoracic echocardiography and IVUS measurements. High-frequency transthoracic echocardiography was reliable in the measurement of the wall thickness and luminal area of the LAD.     

Coronary Artery Wall Thickness of the Left Anterior Descending Artery Using High Resolution Transthoracic Echocardiography – Normal Range of Values

Recently it has been demonstrated that high resolution transthoracic echocardiography (HRTTE) is able to detect differences in the wall thickness of the left anterior descending coronary artery (LAD) between patients with coronary artery disease (CAD) and normal volunteers. We sought to validate this technique, develop a normal range of values and demonstrate the test–retest variability of each measurement. Two hundred forty‐two volunteer participants had a HRTTE study to measure their LAD wall thickness, luminal, and external diameters. Thirty of these subjects had these measurements taken on 3 separate occasions by 2 different echosonographers. All subjects were free of clinical CAD, hypertension, hyperlipidemia, and diabetes mellitus. The average anterior wall thickness was 1.1 ± 0.2 mm; posterior wall thickness was 1.1 ± 0.2 mm, luminal diameter 2.2 ± 0.6 mm, and external elastic membrane (EEM) diameter 4.5 ± 0.9 mm. The bias of the measurements within the same operator for LAD wall thickness, luminal diameter, and EEM was 0.042, ?0.06, and ?0.077 mm, respectively. The bias of the measurements between 2 different operators for LAD wall thickness, luminal diameter, and EEM was 0.082, ?0.077, and ?0.027 mm, respectively. In conclusion, HRTTE measurement of the LAD vessel is reproducible within and between operators in normal volunteers. This technique therefore warrants further study as a potential screening modality for subclinical coronary atherosclerosis.     

Intraoperative evaluation of coronary artery bypass graft anastomoses with high-frequency epicardial echocardiography: experimental validation and initial patient studies

There is currently no accepted approach for intraoperative evaluation of the technical adequacy of coronary artery bypass graft anastomoses. High-frequency epicardial echocardiography performed intraoperatively could assess coronary artery bypass graft anastomoses by providing on-line short-axis (cross-sectional) and longitudinal two-dimensional images of the vessels. To validate measurements of anastomoses with high-frequency epicardial echocardiography, luminal diameter determined by high-frequency epicardial echocardiography was compared with that determined histologically after perfusion fixation in 12 dogs studied after coronary artery bypass grafting. Technical errors were deliberately created in some grafts. The results of these animal validation studies showed that maximum luminal diameter of the anastomosis by high-frequency epicardial echocardiography correlated well with histologic measurements (r = .92; high-frequency epicardial echocardiography = 0.8 histology + 0.3). All deliberately created technical errors were detected by an independent observer using high-frequency epicardial echocardiography. After completion of the animal studies, we demonstrated the clinical applicability of this approach in 12 patients. Fifteen coronary artery bypass graft anastomoses were examined intraoperatively with high-frequency epicardial echocardiography. The measured maximum luminal diameter of the anastomosis was greater than the maximum luminal diameter of the native artery, as expected, in all end-to-side anastomoses. However, the maximum luminal diameter of the side-to-side anastomoses was equal to or slightly less than that of the native artery. In this initial patient group, minor technical errors were noted in two of 15 graft anastomoses. In conclusion, high-frequency epicardial echocardiography can accurately measure coronary arterial bypass graft anastomoses and has potential for intraoperative detection of technical errors and inadequacies.     

Coronary arterial remodeling studied by high-frequency epicardial echocardiography: an early compensatory mechanism in patients with obstructive coronary atherosclerosis

Coronary arterial remodeling is a compensatory mechanism that may limit the adverse effects of coronary obstructive lesions by expansion of the entire vascular segment. To determine if this compensatory anatomic change occurs in patients, high-frequency epicardial echocardiography using a 12 MHz transducer was performed during open heart surgery in 33 patients (10 with normal coronary arteries undergoing valvular surgery and 23 with coronary atherosclerosis). From stop-frame videotape high-frequency epicardial echocardiographic images, cross-sectional measurements of luminal area and total arterial area (lumen, intima, media and dense adventitia) were made in the patients with atherosclerosis at the site of arterial lesions and from the most proximal portion of the same artery. Remodeling was defined as enlargement of the total arterial area. In normal arteries measurements were made from proximal and midarterial locations. In the patients with normal coronary arteries, total arterial area, as determined by high-frequency echocardiography, decreased from the proximal site to the midportion of the artery (from 10.4 +/- 0.9 to 8.4 +/- 1.0 mm2, p less than 0.05); luminal area also decreased (from 6.0 +/- 0.6 to 4.5 +/- 0.7 mm2, p less than 0.05). In patients with coronary arterial lesions, luminal area also decreased from the proximal site to the arterial lesion site (from 5.3 +/- 0.6 to 2.3 +/- 0.3 mm2, p less than 0.05), but total arterial area increased (from 11.6 +/- 1.0 to 13.0 +/- 1.0 mm2, p less than 0.05). Of the 25 coronary arteries evaluated, only 4 had angiographic evidence of coronary collateral formation. These data indicate that coronary arterial remodeling is an important compensatory mechanism in obstructive coronary disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Is Left Ventricular Diastolic Thickening Documented During Dobutamine and Pacing Stress Echocardiography Related to Myocardial Ischemia? An Animal Model Study

Transient increase in diastolic wall thickness (pseudohypertrophy) during pacing stress echocardiography has been reported in normal myocardium. To evaluate the occurrence of pseudohypertrophy and to investigate the contribution of myocardial ischemia on its production during pacing and dobutamine stress echocardiography, we produced a physiologically significant coronary stenosis in 14 open chest dogs. The stenosis in the circumflex artery was measured by quantitative coronary angiography (range: 50% to 89% reduction in luminal diameter), and no resting segmental wall-motion abnormalities were observed by epicardial echocardiography (short-axis, papillary level). In each study, dobutamine (5-40 microg/kg/min) and pacing (up to 260 beats/min) were performed randomly. Positivity of stress echocardiography tests was quantitatively determined by a significant (P < 0.05) reduction or failure to increase in absolute and percent systolic wall thickening in the myocardial area supplied by the stenotic artery as compared to the left anterior descending (LAD) artery-related areas. Diastolic wall thickness and left ventricular diastolic area were compared before and after each stress test in the circumflex and LAD artery-related regions. Pseudohypertrophy was observed in 57% and 86% of dogs for pacing and dobutamine, respectively, in the circumflex region, and in 50% and 64% in the LAD region. Despite its increased incidence in the circumflex region, the augmented diastolic wall thickness did not correlate with coronary stenosis severity or stress test positivity, but correlated inversely with changes in left ventricular diastolic area. In addition, it correlated directly with changes in heart rate only for pacing. In conclusion, pseudohypertrophy was a frequent finding during pacing and dobutamine stress echocardiography tests but was not related to myocardial ischemia in this animal model.     

Usefulness of coronary flow reserve over regional wall motion when added to dual-imaging dipyridamole echocardiography

Vasodilator stress echocardiography allows semi-simultaneous imaging of left anterior descending (LAD) coronary flow and regional wall function. To assess the relative (and additive?) value of regional flow and function for noninvasive identification of angiographically assessed LAD disease in patients with chest pain syndrome, we studied 230 consecutive in-hospital patients (134 men, aged 63.5 +/- 11 years) with chest pain syndrome and normal regional and global left ventricular function. All patients underwent stress echocardiography with dipyridamole (up to 0.84 mg/kg over 10 minutes), including wall motion analysis by 2-dimensional echocardiography and coronary flow reserve (CFR) evaluation of the LAD artery by Doppler, with or without contrast injection. A new regional wall motion abnormality in >or=2 contiguous segments was required for 2-dimensional echocardiographic positivity. CFR was evaluated as the ratio of dipyridamole to peak diastolic coronary blood flow velocity at rest. All patients underwent coronary angiography within 60 days; a quantitatively assessed diameter reduction >50% of the LAD artery was considered significant. Of the 230 patients, 70 had LAD disease. A regional wall motion abnormality in LAD territory was present in 52 patients, and reduced CFR (<1.9) in 62 patients. Sensitivity for detecting LAD disease was 74% for 2-dimensional echocardiography (95% confidence interval [CI] 64% to 84%) and 81% for CFR <1.9 (95% CI 72% to 90%); specificity was 91% (95% CI 87% to 96%) for 2-dimensional echocardiography and 84% for CFR (95% CI 79% to 90%). Accuracy was 86% for 2-dimensional echocardiography (95% CI 82% to 91%) and 83.5% for CFR (95% CI 79% to 88%). When 2-dimensional echocardiography and CFR criteria were considered, sensitivity increased to 93% (95% CI 87% to 99%), with 80.6% specificity (95% CI 74.5% to 86.7%). CFR was assessed during vasodilator stress echocardiography. Its diagnostic accuracy for detecting LAD disease was comparable to regional wall motion abnormalities. However, the data for flow and function can be complementary in terms of predicting underlying angiographic anatomy, because abnormal wall motion can include coronary artery disease, and negative CFR can exclude it.     

Digital two-dimensional echocardiographic imaging of the proximal left anterior descending coronary artery

The use of 2-dimensional echocardiography to evaluate coronary artery anatomy noninvasively and directly has been primarily limited to the evaluation of the left main coronary artery. To determine the feasibility of visualization of the proximal left anterior descending coronary artery (LAD) and assessment for atherosclerotic disease in this location, 128 consecutive patients undergoing coronary arteriography were evaluated with digital 2-dimensional echocardiography. Visualization of the proximal LAD was possible in 90 (70%) of the 128 patients. Of 45 patients with proximal LAD narrowing by angiography, digital echocardiography correctly identified 44 (98% sensitivity). In 27 patients with angiographically normal coronary arteries, digital echocardiography was normal in 18 (67% specificity). In the 18 patients with an angiographically normal proximal LAD but narrowing elsewhere in the coronary system, digital echocardiographic evaluation of the proximal LAD was abnormal in 15. This initial study suggests that 2-dimensional echocardiography is a feasible technique to image the proximal LAD noninvasively in patients undergoing coronary arteriography.     

Reduced aortic distensibility and coronary flow velocity reserve in diabetes mellitus patients with a negative coronary angiogram

BACKGROUND: Structural and functional abnormalities of the aortic wall and disturbances of the coronary circulation with presumed microvascular complications have been reported in patients with diabetes mellitus. OBJECTIVES: To simultaneously establish the coronary flow velocity reserve (CFVR) and aortic distensibility indexes in type 2 diabetes mellitus patients who have normal epicardial coronary arteries by stress transesophageal echocardiography (STEE). METHODS: The elastic properties of the descending aorta and the CFVR were evaluated simultaneously in 18 type 2 diabetes mellitus patients who had negative coronary angiograms. These results were compared with those of 21 nondiabetic subjects with normal epicardial coronary arteries and 24 patients with left anterior descending coronary artery (LAD) stenosis. STEE was used for the evaluation of elastic moduli of the descending aorta. The CFVR was calculated as the ratio of the average peak diastolic flow velocity during hyperemia to that at rest. RESULTS: The CFVR of diabetic patients with normal epicardial coronary arteries and those with LAD stenosis was similarly decreased compared with the controls (2.10+/-0.63 and 1.78+/-0.47 versus 2.76+/-1.25, P<0.05 and P<0.001, respectively). The elastic modulus (in 103 mmHg) was similarly increased in patients with diabetes mellitus and normal epicardial coronary arteries, and in those with LAD stenosis, compared with the control subjects (0.94+/-0.82 and 0.91+/-0.59 versus 0.49+/-0.19, P<0.05 and P<0.05, respectively). CONCLUSIONS: It may be stated that reduced aortic distensibility (increased elastic modulus) and the CFVR were demonstrated simultaneously during STEE in diabetic patients compared with nondiabetic subjects with negative coronary angiograms.     

老年患者1000例超声心动图分析

目的 了解老年人常见心血管基础病因以及导致的心脏结构与功能的改变。方法 对1000例老年人行超声心动图检查,按年龄、病因分组,分别测量左房内径（LAD）、短轴缩短率（FS%）、室间隔厚度（IVST）、左室后壁厚度（PWT）、右室舒张末左右径（RVDd)、右室收缩末左右径（RAD）、舒张早期最大流速/心房收缩期最大流速（E/A）。结果 患者主要集中在60～69岁、70～79岁2个年龄组,病因主要集中在冠心病（39.3%）、高血压病（18.5%）。LAD、E/A,在60～69岁、80岁以上年龄组差异显著,冠心病、高血压病组LAD均明显高于对照组,高血压病组的IVST、PWT明显增高,E/A在各组均小于1,尤以冠心病,高血压病组为低。结论 年龄及各种心血管疾病可影响心脏结构和功能的改变。     

Variable morphology of coronary atherosclerosis: characterization of atherosclerotic plaque and residual arterial lumen size and shape by epicardial echocardiography.

The purpose of this study was to evaluate the in vivo characteristics of coronary atherosclerosis by using high frequency epicardial echocardiography. High frequency epicardial echocardiography was used to evaluate residual lumen and wall morphology at the sites of maximal coronary atherosclerosis in 26 patients undergoing coronary artery bypass grafting. The maximal/minimal wall thickness ratio was 3.1 +/- 0.2 (mean +/- SEM) with a large range (1.3 to 7.5). Portions of the wall were normal in 16 of 31 lesions; the percent normal circumference ranged from 9% to 85%. Maximal/minimal lumen diameter ratio was 1.5 +/- 0.1 (range 1.1 to 2.9). The shape of the residual coronary lumen was noncircular in 16 lesions: oval in 13 and complex in 3. The residual coronary lumen was eccentrically placed within six arteries. These data emphasize the variability of residual lumen and wall geometry in atherosclerosis.     

Echocardiographic epicardial fat thickness and coronary artery disease.

BACKGROUND: The association between epicardial fat and coronary artery disease has not been evaluated. The objective of the present study was to evaluate the relationship of echocardiographic epicardial fat to the presence and severity of coronary artery disease in a clinical setting. METHODS AND RESULTS: Two hundred and three consecutive patients who underwent echocardiography and diagnostic coronary angiography were studied. The epicardial fat thickness on the free wall of the right ventricle was measured at end-diastole from the parasternal long-axis views of 3 cardiac cycles. Coronary angiograms were analyzed for the extent and severity of coronary artery disease using Gensini's score. The patients were divided into 2 groups according to the fourth quartile of epicardial fat thickness (Group I <7.6 mm; Group II > or =7.6 mm). There were no significant differences in the baseline characteristics except for waist circumference (p=0.023). Significant correlations were demonstrated between epicardial fat thickness and age (r=0.332, p<0.001), C-reactive protein (r=0.182, p=0.009), body mass index (r=0.142, p=0.044) and waist circumference (r=0.229, p=0.001). The patients with a higher epicardial fat thickness were associated with a high Gensini's score (p=0.014). Multivariate analysis showed that age (odds ratio (OR) 5.29, p=0.003), epicardial fat thickness (OR 10.53, p=0.004), diabetes (OR 8.06, p=0.006) and smoking (OR 14.65, p=0.015) were independent factors affecting significant coronary artery stenosis. CONCLUSIONS: Epicardial fat thickness was significantly correlated with the severity of coronary artery disease in patients with known coronary artery disease.     

Changes in left anterior descending coronary artery wall thickness detected by high resolution transthoracic echocardiography

Recently, it has been demonstrated that high-resolution transthoracic echocardiography (HRTTE) is able to detect differences in the wall thickness of the left anterior descending coronary artery (LAD) between patients with coronary artery disease (CAD) and normal volunteers. The aim of this study was to further validate this technique. One hundred ten volunteers, 58 patients with angiographically proved CAD and 52 control subjects, underwent assessments of their LADs using HRTTE. Anterior and posterior wall thicknesses differed between subjects in the CAD group and controls (1.9 +/- 0.6 vs 1.2 +/- 0.3 mm, p <0.001, and 1.8 +/- 0.5 vs 1.2 +/- 0.3 mm, p <0.001, respectively). External LAD diameter was also greater in subjects in the CAD group compared with controls (5.2 +/- 1.9 vs 4.4 +/- 0.9 mm, respectively, p = 0.01). However, there was no difference in luminal diameter between subjects in the CAD group and the controls (1.9 +/- 0.9 vs 2.1 +/- 0.8 mm, respectively, p = 0.3). In conclusion, HRTTE demonstrated that LAD wall thicknesses and external diameters in patients with CAD were significantly larger than in normal volunteers. Luminal diameter, however, was maintained in the 2 groups, indicating that subjects in the CAD group had undergone positive remodeling at the site measured. This objectively visualized evidence of coronary atherosclerosis with HRTTE would likely be undetected during coronary angiography.     

Comparison of transthoracic Doppler echocardiography to intracoronary Doppler guidewire measurements for assessment of coronary flow reserve in the left anterior descending artery for detection of restenosis after coronary angioplasty

Transthoracic Doppler echocardiography (TDE) has been described as a feasible and accurate technique to noninvasively assess coronary flow reserve (CFR) in the left anterior descending artery (LAD). This study was designed to evaluate whether serial assessment of CFR in the LAD using TDE allows detection of restenosis after previously performed angioplasty. Thirty-three consecutive patients with single-vessel coronary artery disease of the LAD scheduled for angioplasty underwent assessment of coronary flow velocity at rest and during adenosine-induced hyperemia in the distal LAD using high-frequency TDE. CFR was calculated as the ratio of hyperemic to basal systolic/diastolic mean velocity. Investigations were performed before and immediately after angioplasty, and at the time of control angiography after 3 months. CFR results by TDE were compared with intracoronary Doppler guide wire measurements. Adequate pulse-wave Doppler signals to measure CFR were obtained in 30 patients (91%) using TDE. There was close correlation between echocardiographically and intracoronary derived CFR results (r = 0.80, 0.79, and 0.87 before angioplasty, early after, and at 3- month control angiography, respectively; p <0.001). Using a cut-off value of CFR < or =2.0 to identify significant coronary artery disease, TDE detected LAD restenosis with a sensitivity of 89% and specificity of 90%. Thus, high-frequency TDE is a feasible technique to noninvasively assess CFR in the LAD with results closely corresponding to invasive measurements. Defining a cut-off value of CFR < or =2.0, the technique has the potential to reliably detect LAD stenosis after coronary intervention.     

Decreased aortic distensibility and coronary flow velocity reserve in patients with significant aortic valve stenosis with normal epicardial coronary arteries

BACKGROUND AND AIM OF THE STUDY: A number of clinical and experimental studies have suggested that aortic valve stenosis (AS) is a manifestation of atherosclerotic process. Previous studies have revealed a decreased coronary flow velocity reserve (CFR) in AS patients in consequence of left ventricular hypertrophy. The hypothesis was tested that the elastic properties of the descending aorta of AS patients might indicate signs of stiffness of the aorta. METHODS: The CFR and indices of aortic distensibility as functional markers of the descending aorta were compared in three different patient populations: (i) control subjects without valvular and coronary artery disease; (ii) patients with AS with normal epicardial coronary arteries; and (iii) patients with significant left anterior descending coronary artery (LAD) stenosis. CFR measurements were carried out according to a standard protocol, using vasodilatory stimulation with dipyridamole (0.56 mg/kg for 4 min), and peak diastolic velocity measurements at 6 min. The elastic properties of the aorta were calculated from echocardiographic parameters and blood pressure data. RESULTS: The CFR in AS patients was decreased to a similar extent as in patients with LAD stenosis. The aortic distensibility indices were similarly significantly increased in patients with AS and normal epicardial coronary arteries and with LAD stenosis, as compared with controls. CONCLUSION: These results indicate that the descending aorta exhibits appreciable increased stiffness in AS patients with normal epicardial coronary arteries.     

Assessment of coronary blood flow in hypertrophic cardiomyopathy using thrombolysis in myocardial infarction frame count method

BACKGROUND: Coronary microvascular dysfunction has been reported to be present in patients with hypertrophic cardiomyopathy (HCM) despite normal epicardial coronary arteries. In this study we aimed to evaluate coronary blood flow in patients with HCM by means of Thrombolysis In Myocardial Infarction (TIMI) frame count. METHODS: Thirty-two patients with HCM (22 male, 10 female; mean age=48+/-7 years) and 36 healthy control subjects (23 male, 13 female; mean age=49+/-7 years) without any cardiovascular disease were included in the study. All patients and control subjects were selected from individuals who underwent coronary angiography and left heart catheterization in our hospital and were found to have angiographically normal coronary arteries. All patients had an asymmetrically hypertrophic nondilated left ventricle and a basal intraventricular pressure gradient>30 mmHg recorded in the left ventricular outflow tract. A complete transthoracic echocardiographic examination including two-dimensional, M-mode, pulse and continuous Doppler was performed in all patients and control subjects. Coronary flow rates of all subjects were documented by the TIMI frame count method. To obtain corrected TIMI frame count for the left anterior descending (LAD) coronary artery, TIMI frame count for this vessel was divided by 1.7. RESULTS: Corrected TIMI frame count for the LAD coronary artery was found to be significantly higher in patients with HCM compared to control subjects (35+/-8 vs. 25+/-6, p<0.001). However, we found no significant difference between patients and control subjects regarding TIMI frame counts for the left circumflex (LCx) coronary artery and the right coronary artery (RCA) (LCx: 28+/-6 vs. 26+/-6, p=0.07 and RCA: 26+/-6 vs. 24+/-5, p=0.09). Besides, the corrected TIMI frame count for the LAD coronary artery was found to be significantly correlated with interventricular septal wall thickness (r=0.546, p=0.001) and interventricular septal/posterior wall thickness ratio (r=0.490, p=0.004). However, no significant correlation was detected between the corrected TIMI frame count for the LAD coronary artery and other echocardiographic variables. CONCLUSION: We show that patients with HCM had significantly higher corrected TIMI frame counts for the LAD compared to the control subjects. No such difference was detected between the two groups regarding TIMI frame counts for the LCx and RCA, suggesting the presence of regional (interventricular septal) rather than global impairment of coronary blood flow in patients with HCM.     

Comparison of two- and three-dimensional transthoracic echocardiography in the assessment of trabeculations and trabecular mass in left ventricular noncompaction

Twenty-one patients (mean age 47.5 years, 9 females) with left ventricular noncompaction (LVNC) diagnosed by both two-dimensional transthoracic echocardiography (2DTTE) and live/real time three-dimensional transthoracic echocardiography (3DTTE) were included in the study. Left ventricular (LV) mass was calculated with epicardial and endocardial border tracings first including the LV trabeculations and then excluding them. LV trabecular mass was then derived as the difference between the two measurements. This was done by 2DTTE using the modified biplane Simpson's method and by live/real time 3DTTE using the Tom Tec imaging system. The number of trabeculations arising from each segment of LV walls as well as the segmental distribution of trabeculations were also assessed by both 2DTTE and 3DTTE. The calculated LV trabecular mass by 3DTTE (mean 11.8 +/- 5.5 g) was significantly greater than 2DTTE (mean 7.3 +/- 4.3 g, P = 0.005). The total number of trabeculations assessed by 3DTTE (mean 11.2 +/- 3.3) was also significantly greater than 2DTTE (mean 3.76 +/- 1.2, P < 0.0001). The values for inter- and intraobserver variability were lower for 3DTTE than 2DTTE. In conclusion, both LV trabecular mass as well as the total number of trabeculations in patients with LVNC were significantly underestimated by 2DTTE as compared to 3DTTE.     

Myocardial Contrast Echocardiography in Assessment of Stable Coronary Artery Disease at Intermediate Dobutamine-Induced Stress Level

Background: Myocardial contrast stress echocardiography (stress MCE) is a novel method for diagnosing coronary artery disease (CAD). Few studies have compared the diagnosis of ischemia by stress MCE to angiographic CAD. Methods: Dobutamine stress MCE and SonoVue contrast infusion were performed before an elective percutaneous coronary intervention in 37 patients (8 women) aged 45–75 years with symptomatic CAD and at least one significant coronary artery stenosis measured by quantitative coronary angiography (QCA). The total and regional perfusion and wall motion (WM) were scored as normal or abnormal and attributed to the three main epicardial coronary arteries using a 17-segment left ventricular model. Results: An intermediate stress level was obtained in 29 (78%) patients, and 2 (5%) patients obtained peak stress. A perfusion defect was detected in 92% and WM abnormality in 57% of the patients at peak stress (P < 0.01). By perfusion, 70% of stenoses were both detected and correctly anatomically located, compared to 42% by WM (P < 0.01). All 21 patients with multivessel disease and/or proximal left anterior descending (LAD) stenosis measured by QCA were identified by stress-induced perfusion defects, while only 11 of them were identified by WM abnormalities (P < 0.01). Conclusion: Perfusion scoring is superior to WM scoring during stress MCE for diagnosing significant CAD in patients obtaining intermediate stress level, in particular, when multivessel disease or proximal LAD stenosis is present.     

Ischemic heart disease evaluated using dipyridamole-stress two-dimensional echocardiography

Dipyridamole-stress two-dimensional echocardiography (2DE) was performed in 25 subjects, 14 with stenotic and 11 with normal coronary arteries by coronary angiography, to assess the sites and severity of coronary artery stenosis noninvasively. Dipyridamole was administered intravenously with a dose of 0.56 mg/kg for 4 min. 2DE was recorded at the lower papillary muscle level and the percent fractional area change (% FAC) of the left ventricular segments was computed (FV). In all cases with an echocardiographic regional wall motion abnormality in the interventricular septum, a significant stenosis (greater than or equal to 75%) was documented angiographically in the left anterior descending coronary artery (LAD). In seven of eight patients with a segmental abnormality in the inferolateral wall, a significant stenosis was observed in the left circumflex coronary artery (Cx). The sensitivity and specificity of dipyridamole-stress echocardiography were 100% and 92%, respectively, for an LAD stenosis, and and 87.5% and 71%, respectively, for a Cx stenosis. The segmental wall motion abnormality induced by dipyridamole resolved within four to five min after terminating the infusion in patients with coronary artery narrowing of 75%; whereas, it persisted up to six to seven min in patients with 90% narrowing. There was no improvement in the LV wall motion 15 min after the termination of the infusion in patients with severe narrowing (99%). In conclusion, dipyridamole-stress echocardiography proved to be one of the most useful methods, not only for detecting coronary artery disease, but for predicting the severity and for localizing the sites of lesions as well.