Comparison of postexercise and transesophageal atrial pacing two-dimensional echocardiography for detection of coronary artery disease

Two-dimensional (2-D) echocardiography during transesophageal atrial pacing (TAP) was recently proposed as an alternative to exercise 2-D echocardiography for the diagnosis of coronary artery disease (CAD). To compare these 2 methods, 78 consecutive patients with good-quality echocardiographic (echo) examinations at rest were studied. Two-dimensional echocardiography was performed immediately after supine bicycle exercise and at peak atrial pacing obtained with transesophageal atrial stimulation. Twenty patients were excluded: 16 because of poor quality of 2-D echo images after exercise and 4 because of inadequate TAP studies (atrial capture not achieved in 2 and intolerance in 2). Of the remaining 58 patients, 39 had significant CAD (at least 75% diameter stenosis of at least 1 major coronary artery) and 19 had no significant CAD. The 2 test responses were considered positive if a wall motion abnormality was detected during pacing or after exercise. Sensitivity and specificity were 82% and 95% after exercise and 90% and 84% during TAP. In patients with significant CAD but without wall motion abnormalities at rest, sensitivity was 75% during pacing and 56% after exercise. In patients with significant CAD, the wall motion score index decreased significantly with both types of stress; during pacing wall motion score index was significantly lower than after exercise. Thus, 2-D echo during TAP appears to be a feasible and reliable alternative to postexercise echo for the detection of CAD.     

Evaluation of Doppler echocardiography stress test with transesophageal atrial pacing in detecting coronary artery disease

Doppler echocardiographic transesophageal atrial pacing stress test was performed in 23 patients with coronary artery disease (CAD) and 35 normal subjects. It was found that 1/3 filling fraction (1/3 FF) decreased and peak flow velocity of atrial contraction (APFV), time velocity integral of atrial contraction (ATVI) and the ratio of ATVI to total TVI (ATVI/TTVI) increased immediately after rapid atrial pacing in CAD group. No differences were found between before and after pacing in normal group. Using 2 of the 3 criteria ATVI/TTVI greater than 0.35, ATVI increases and 1/3 FF decreases after pacing as the criteria for diagnosis in CAD, the sensitivity was 86% and specificity was 77%. Thus, Doppler echocardiographic transesophageal atrial pacing stress test may be a feasible, reliable and noninvasive method in detecting CAD.     

Coronary Doppler intensity changes during handgrip: a new method to detect coronary vasomotor tone in coronary artery disease.

OBJECTIVES: This study evaluates whether a quantitative measurement of Doppler intensity during handgrip may disclose coronary vasomotor dysfunction in patients with coronary artery disease (CAD). BACKGROUND: Atherosclerotic coronary segments show an exaggerated constrictive response to handgrip. The intensity of the scattered Doppler signal is proportional to the number of blood cells flowing through the vessel, and should be reduced during vasoconstriction. Therefore, changes in coronary flow during handgrip may be detected by measuring Doppler intensity rather than velocities. METHODS: The distal left anterior descending coronary artery (LAD) was imaged by high-resolution transthoracic color Doppler echocardiography during handgrip in 47 patients: 15 with normal coronary arteries and 32 with significant CAD involving the LAD. The Doppler signal was acquired at 70 dB dynamic range at baseline, 30-s handgrip and 5 min recovery. Peak and mean flow velocity, pressure half-time, deceleration time (ms), deceleration rate (cm/s2) and mean gray level intensity (intensity units [IU]) of the Doppler spectrum were measured in diastole. RESULTS The velocity parameters did not change significantly during handgrip both in normal and CAD patients. The Doppler intensity significantly decreased during handgrip (from 87.0 +/- 32.8 to 57.7 +/- 35.3 IU; p < 0.001) in patients with CAD, and it increased or remained unchanged in normals (from 74.1 +/- 27.3 to 85.1 +/- 31.2 IU; p = NS). The sensitivity of Doppler intensity in detecting CAD was 84.4%, specificity 93.3%, negative predictive value 73.7% and positive predictive value 96.4%. CONCLUSIONS: Doppler intensity measured by transthoracic echocardiography during handgrip allows the detection of CAD and coronary vasomotor dysfunction.     

Transmitral blood flow velocity patterns evaluated by pulsed Doppler echocardiography in diagnosing transient myocardial ischemia

To evaluate the influences of transient myocardial ischemia on transmitral blood flow velocity patterns, pulsed Doppler echocardiography was performed during coronary artery occlusion in 10 anesthetized open-chest dogs, and also during esophageal pacing or the administration of dipyridamole in 79 patients with coronary artery disease (CAD), and in 19 control subjects. During occlusion of the coronary artery, an abrupt decrease in the peak velocity of the rapid filling wave (R) was noted within one min simultaneously with rapid decrease of % wall thickening in the ischemic regions. The peak velocity of atrial filling was augmented compensatorily. Although the transmitral blood flow velocity pattern did not change in the controls with esophageal pacing, changes similar to those which were obtained during experimental studies were demonstrated in CAD patients. There were no significant differences between transmitral blood flow velocity patterns of patients with multivessel disease and those with single vessel disease. Ischemic changes in transmitral blood flow velocity patterns were not demonstrated in patients with mitral regurgitation. Sublingual nitroglycerin normalized post-pacing abnormal blood flow velocity patterns. In contrast, after the intravenous administration of 0.56 mg/kg of dipyridamole, R and A were increased and the A/R ratio was unchanged both in CAD patients and the control groups. Deceleration time, or the half time, was prolonged during both provocation tests in CAD patients, and these changes were transient and were restored within several min. Furthermore, they were noted more frequently than was the development of ST depression on ECG, or chest pain. These findings indicate that the transmitral blood flow velocity patterns obtained by pulsed Doppler echocardiography are useful for detecting transient myocardial ischemia, though they have limitations in diagnosing the extent of coronary artery disease.     

Tissue Doppler imaging (TDI) for on-line detection of regional early diastolic ventricular asynchrony in patients with coronary artery disease

Diastolic filling of the left ventricle is often impaired in patients with coronary artery disease (CAD) in the absence of systolic wall motion abnormalities or previous myocardial infarction. The current study was designed to assess the ability of tissue Doppler imaging (TDI) for on-line detection of regional diastolic wall motion abnormalities to identify CAD in patients with preserved systolic function. 20 normal subjects (age 51 ± 13years) and 17 CAD patients with normal systolic function and 70% luminal narrowing of the LAD (age 56 ± 11years) were included. Coronary anatomy was unknown to the echocardiographer. In the parasternal short axis and the apical 4-chamber-view, peak tissue velocities of the anterior/inferior and the midseptal/midlateral LV segments during rapid ejection (RE), isovolumic relaxation (IR), rapid filling (RF) and atrial contraction (AC) were analyzed by color-M-Mode-TDI. In the apical view, in 13 of 35 (37%) patients with adequate recordings, myocardial asynchrony was detected during IR: while the septum was moving inwards (red color-coding), the lateral wall was moving outwards (blue/green coding). In the remaining 22 patients (63%) a slow, synchronous outward motion of septum and lateral wall with homogeneous color-coding (blue/green) was seen. Unblinding of the coronary status revealed a critical LAD stenosis in all 13 patients (100%) with myocardial asynchrony. Analysis of midseptal peak velocities during IR revealed positive velocities (1.22 ± 1.64cm/s) in CAD patients and negative velocities (–1.39 ± 0.81cm/s) in normal subjects. Thus, TD1 allowed for the on-line detection of early diastolic asynchrony in 13 of 16 (82%) patients with critical LAD-narrowing. Due to the rapid assessment of regional wall motion abnormalities, TDI might help to identify CAD in patients with normal systolic function.     

Changes in Doppler indices of cardiac function during and after percutaneous transluminal coronary angioplasty.

OBJECTIVE--To assess the sensitivities of Doppler indices to changes in global cardiac function during and after controlled myocardial ischaemia induced by coronary angioplasty. DESIGN--Continuous wave Doppler signals of aortic flow were recorded during coronary angioplasty. The following Doppler indices of cardiac function were measured before, during, and after balloon inflation: V (peak velocity), MA (mean acceleration), V2/T (T = time from onset to peak ejection), and MD (minute distance corrected for baseline heart rate). SETTING--A tertiary care cardiological unit in a university hospital. PATIENTS--Sixteen patients undergoing coronary angioplasty of the left anterior descending coronary artery. Eight patients had multivessel disease. MAIN OUTCOME MEASURES--The primary outcome measures were planned before data collection began. RESULTS--12 patients showed a significant fall of three or more Doppler indices from their baseline values during balloon inflation. This occurred in all patients with multivessel disease. The Doppler indices V2 T, MD, V, and MA fell by 43.7%, 37.7%, 27.4%, and 23% respectively from their baseline values (p less than 0.0001). The relative sensitivities of the Doppler indices to ischaemia were V2/T greater than MD (p less than 0.02), MD greater than (p less than 0.001), and V greater than MA (p less than 0.01). The impairment of global left ventricular function resulting from brief balloon inflation during single vessel angioplasty was reversible in all the patients. CONCLUSIONS--The Doppler indices V2/T, MD, V, and MA are all sensitive, in order of magnitude, to falls in global cardiac function resulting from ischaemia. They may prove useful for assessing cardiac function during ischaemia in the clinical setting.     

Changes in Doppler indices of cardiac function during and after percutaneous transluminal coronary angioplasty.

OBJECTIVE--To assess the sensitivities of Doppler indices to changes in global cardiac function during and after controlled myocardial ischaemia induced by coronary angioplasty. DESIGN--Continuous wave Doppler signals of aortic flow were recorded during coronary angioplasty. The following Doppler indices of cardiac function were measured before, during, and after balloon inflation: V (peak velocity), MA (mean acceleration), V2/T (T = time from onset to peak ejection), and MD (minute distance corrected for baseline heart rate). SETTING--A tertiary care cardiological unit in a university hospital. PATIENTS--Sixteen patients undergoing coronary angioplasty of the left anterior descending coronary artery. Eight patients had multivessel disease. MAIN OUTCOME MEASURES--The primary outcome measures were planned before data collection began. RESULTS--12 patients showed a significant fall of three or more Doppler indices from their baseline values during balloon inflation. This occurred in all patients with multivessel disease. The Doppler indices V2 T, MD, V, and MA fell by 43.7%, 37.7%, 27.4%, and 23% respectively from their baseline values (p less than 0.0001). The relative sensitivities of the Doppler indices to ischaemia were V2/T greater than MD (p less than 0.02), MD greater than (p less than 0.001), and V greater than MA (p less than 0.01). The impairment of global left ventricular function resulting from brief balloon inflation during single vessel angioplasty was reversible in all the patients. CONCLUSIONS--The Doppler indices V2/T, MD, V, and MA are all sensitive, in order of magnitude, to falls in global cardiac function resulting from ischaemia. They may prove useful for assessing cardiac function during ischaemia in the clinical setting.     

Assessment of left ventricular ejection dynamics in patients with coronary artery disease during dipyridamole-stress Doppler echocardiography

OBJECTIVES: To investigate the contribution of Doppler-echocardiographically derived aortic indexes of left ventricular systolic function during dipyridamole-stress to the diagnosis of coronary artery disease (CAD). DESIGN: This was a clinical study. METHODS: Echocardiographic studies under baseline and peak dipyridamole stresses were performed on 15 normal subjects and 32 patients with angiographically confirmed CAD. Peak Doppler velocity, acceleration, and acceleration time of the ascending aorta, as well as segmental left ventricular wall motion, were analyzed. RESULTS: The sensitivity, specificity and overall accuracy of wall-motion abnormalities induced by dipyridamole for the detection of CAD were 62.5, 100, and 74.5%, respectively. When wall-motion abnormalities were combined with the percentage changes in peak aortic velocity and acceleration, the overall sensitivities were 84.38 and 78.15%, respectively, the specificities were 66.7 and 80.00%, respectively, and the accuracy was 78.72% for both models. When all three parameters were combined, the sensitivity, specificity and overall accuracy of the method were 87.5, 86.7, and 87.2%, respectively. CONCLUSIONS: Doppler-echocardiographically derived aortic indexes of left ventricular systolic function during dipyridamole stress could be a useful adjunct to two-dimensional echocardiography by improving its sensitivity in the diagnosis of CAD.     

Simultaneous dobutamine stress echocardiography and dobutamine scintigraphy (99mTc-MIBI-SPET) for assessment of coronary artery disease

Background: Simultaneous dobutamine stress echocardiography (DSE) and^99mTc-MIBI-SPET (DMS) for the evaluation of the presence and the extent of coronary artery disease (CAD) were assessed for a head to head comparison regarding the diagnostic accuracy of the two tests. Methods and Results: Forty-five consecutive patients (33 males and 12 females: 53±6.8 yr.) underwent exercise electrocardiography and simultaneous dobutamine stress echocardiography and MIBI-SPET imaging. Coronary angiography was performed in all patients (significant coronary stenosis > 50%). On the basis of the results of exercise electrocardiogram the pre-test probability for coronary artery disease (Diamond's algorithm) was low (45.6±12.7 %). The overall specificity, sensitivity and predictive accuracy of Echo-dobutamine stress test for diagnosis of the presence or absence of CAD were: specificity 82%, sensitivity 76%, diagnostic accuracy 80%, positive predictive value 90%, negative predictive value 40%. The overall specificity, sensitivity and predictive accuracy of MIBI-SPET-dobutamine test for diagnosis of the presence or absence of CAD were: specificity 86%, sensitivity 87%, diagnostic accuracy 84%, positive predictive value 97%, negative predictive value 54%. MIBI-SPET-dobutamine test showed a significantly higher sensitivity in comparison with ECHO-dobutamine test (P<0.05). Conclusion: Both noninvasive methods for the detection of CAD showed a good diagnostic accuracy. Nevertheless the SPET model showed an higher sensitivity in comparison with DSE model, essentially in the presence of a lower extent of CAD and during submaximal test.     

Pulsed Doppler assessment of left ventricular diastolic filling in coronary artery disease before and immediately after coronary angioplasty

To determine if left ventricular (LV) diastolic filling abnormalities are detectable by Doppler echocardiography in patients with coronary artery disease (CAD), 34 patients with CAD and 24 normal, age-matched control subjects underwent mitral valve pulsed Doppler examination. At catheterization, all CAD patients had typical angina, at least 70% diameter narrowing of 1 major coronary artery, ejection fraction of 50% or more and no valvular heart disease. Seventeen CAD patients underwent coronary angioplasty and had a Doppler examination 1 day before and 1 day after the procedure. Doppler diastolic time intervals, peak velocities at rapid filling (E velocity), atrial contraction (A velocity) and the ratio peak E/peak A velocities were measured. The following areas under the Doppler velocity envelope and their percentage of the total area were calculated: first third of diastole (0.33 area), triangular area under the peak E velocity (E area), and triangular area under the peak A velocity (A area). Patients with CAD and normal subjects were significantly different (p less than 0.01) in peak E velocity (CAD 0.60 +/- 0.12 m/s, normal 0.68 +/- 0.12 m/s), peak A velocity (CAD 0.59 +/- 0.12 m/s, normal 0.48 +/- 0.11 m/s), ratio peak E/peak A velocities (CAD 1.0 +/- 0.27, normal 1.5 +/- 0.32), A area (CAD 0.052 +/- 0.015 m, normal 0.036 +/- 0.010 m), ratio E area/A area (CAD 1.7 +/- 0.53, normal 2.5 +/- 0.69), and all area fractions. In the CAD patients who had undergone coronary angioplasty, no differences were found in any Doppler index before and immediately after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of dipyridamole-Doppler echocardiography for detection of myocardial ischemia and coronary artery disease

Doppler assessment of left ventricular filling and ejection during dipyridamole stress may supplement wall motion analysis for detection of myocardial ischemia and coronary artery disease (CAD). Thirty-four patients taking no cardioactive therapy were studied using intravenous dipyridamole (0.6 mg/kg) during 2-dimensional and pulsed Doppler echocardiography. Twelve patients had normal coronary arteries (group 1) and the remainder, who had significant CAD, were divided into groups 2 (n = 11) and 3 (n = 11). Only subjects in group 2 developed myocardial ischemia manifest as reversible regional asynergy and ST-segment depression. Heart rate increased (16 +/- 9 beats/min, p less than 0.01) and mean blood pressure decreased (-5 +/- 8 mm Hg, p = not significant) uniformly across groups. Exaggerated hyperkinesia of normally contracting wall segments was the common response to dipyridamole infusion in patients with CAD. The respective mean percent changes in peak early diastolic velocity, peak atrial velocity, their ratio and ejection peak velocity, and mean acceleration for groups 1 (20, 42, -13, 20 and 23%), 2 (22, 32, -2, 10 and 14%) and 3 (23, 33, -6, 16 and 18%) were similar. Comparisons between normal patients and those with CAD and between groups 2 and 3 revealed no significant differences in the effect of dipyridamole on any variable. However, a decrease in both peak velocity and mean acceleration of left ventricular ejection was seen in 3 of 4 group 2 patients who developed severe ischemia. Dipyridamole-Doppler echocardiography is insensitive for detection of CAD and appears unable to identify myocardial ischemia unless this is severe. Hemodynamic changes and compensatory wall motion induced by dipyridamole may explain these findings.     

Platelet activation in stable coronary artery disease

To elucidate the role of physical activity in the pathogenesis of acute ischemic syndromes in patients with coronary artery disease (CAD), we hypothesized that platelet activation occurs when coronary blood flow velocity and shear stress increase across an atherosclerotic vascular bed. We measured platelet aggregation by using angiologic catheterization to obtain simultaneous samples of whole blood from the coronary sinus and the aorta white at rest, 2 minutes after the onset of rapid atrial pacing, and 10 minutes after termination of pacing. Of 82 consecutive patients included in our study, 36 had stenosis of the left coronary artery, 12 had stenosis of the right coronary artery only, and 34 had no evidence of CAD. Samples taken at rest revealed no arteriovenous difference in platelet aggregation between patients with CAD and those without CAD. In patients with significant stenosis (≥50%) of the left coronary artery, atrial pacing caused platelet aggregation to increase in samples from the coronary sinus (64 ± 9% increase; p < 0.01) but not in blood from the aorta (2 ± 8% decrease; difference not significant). This increase was transient, with aggregation returning almost to resting values 10 minutes after pacing ended. Atrial pacing elicited no change in platelet aggregation in samples from either the coronary sinus or aorta of patients with nonsignificant stenosis (<50%) of the left coronary artery, patients with significant stenosis of the right coronary artery only, and patients free of CAD. Thus, under resting conditions, no evidence of platelet activation across the coronary bed was seen regardless of CAD status. However, significant stenosis was associated with heightened platelet activation and aggregation when coronary blood flow was increased with atrial pacing.     

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.     

Comparison of dipyridamole-Doppler echocardiography to thallium-201 imaging and quantitative coronary arteriography in the assessment of coronary artery disease

This study was undertaken to determine whether Doppler measurements of systolic aortic and diastolic mitral blood flow velocities could reliably detect the presence of reversible myocardial perfusion defects during intravenous dipyridamole-thallium-201 imaging. In addition, the ability of dipyridamole-Doppler echocardiography to predict the presence of significant coronary artery disease (CAD) was evaluated. Baseline and post-dipyridamole Doppler studies were performed in 10 normal control subjects and 23 patients with CAD. Aortic peak velocity and acceleration increased from baseline to post-dipyridamole in normal subjects by 0.07 +/- 0.07 m/s (p = 0.016) and 2.1 +/- 2.0 m/s2 (p = 0.009), respectively. The ratio of early to late peak transmitral velocities decreased slightly in normal subjects, by 0.18 +/- 0.72 (difference not significant), whereas the ratio of early to late transmitral velocity-time integrals increased by 0.07 +/- 0.93 (difference not significant). The response of aortic velocity and acceleration to intravenous dipyridamole was not significantly different between normal subjects, patients without reversible thallium-201 perfusion defects and patients with reversible thallium-201 perfusion defects. Furthermore, only 3 of 14 subjects with reversible thallium-201 perfusion defects had abnormal (greater than 2 standard deviations from the mean) responses of aortic velocity or acceleration to intravenous dipyridamole. No patient had an abnormal response of the early to late mitral peak velocity ratio. In addition, the response of Doppler aortic and mitral indexes to intravenous dipyridamole was not able to identify the presence of significant CAD as assessed by quantitative coronary arteriography.(ABSTRACT TRUNCATED AT 250 WORDS)     

Noninvasive detection of total occlusion of the left anterior descending coronary artery with transthoracic Doppler echocardiography.

OBJECTIVES: The purpose of this study was to evaluate the value of transthoracic Doppler echocardiography (TTDE) for the noninvasive detection of total left anterior descending coronary artery (LAD) occlusion. BACKGROUND: Total coronary occlusion is associated with an adverse long-term prognosis, and mechanical revascularization may be required for the patient with total coronary occlusion. However, a noninvasive diagnosis of total coronary occlusion before coronary angiography (CAG) has been difficult, especially in patients without clinical signs. METHODS: We studied 103 consecutive patients who underwent CAG for the evaluation of coronary artery disease. The study group consisted of 16 patients with total LAD occlusion (group A) and 87 patients without total LAD occlusion (group B). Coronary flow velocity in the mid-portion of the LAD was recorded by TTDE. RESULTS: Adequate spectral Doppler recordings of diastolic flow in the LAD were obtained in 98 study patients (95%; 15 patients in group A and 83 patients in group B). In group A, retrograde LAD flow was obtained in 14 (93%) of 15 patients. The mean diastolic velocity of the retrograde flow was 21.0 +/- 6.1 cm/s. In group B, antegrade LAD flow was obtained in all 83 patients (100%). The mean diastolic velocity of the antegrade flow was 21.5 +/- 7.1 cm/s. Retrograde LAD flow by TTDE had a sensitivity of 93% and a specificity of 100% for the detection of total LAD occlusion. CONCLUSIONS: Retrograde flow in the LAD by TTDE is a highly sensitive and specific finding that can be used to noninvasively diagnose total LAD occlusion.     

Noninvasive coronary flow velocity reserve measurement in the posterior descending coronary artery for detecting coronary stenosis in the right coronary artery using contrast-enhanced transthoracic Doppler echocardiography

BACKGROUND: Coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) has been found to be useful for assessing left anterior descending coronary artery (LAD) stenosis. However, this method has been restricted only for the LAD. The purpose of this study was to detect severe right coronary artery (RCA) stenosis by CFVR measurement using contrast-enhanced TTDE. METHODS: In 60 consecutive patients with angina pectoris (mean (SD) age: 60 (11), 18 women), coronary flow velocities in the RCA were recorded in the postero-descending coronary artery by contrast-enhanced TTDE at rest and during hyperemia induced by intravenous infusion of adenosine triphosphate (140 mcg/ml/kg). CFVR was calculated as the ratio of hyperemic to basal peak and mean diastolic flow velocity. CFVR measurements by TTDE were compared with the results of coronary angiography performed within 1 week. RESULTS: Coronary flow velocity was successfully recorded in 49 (82%) of the 60 patients with contrast agent. CFVR (mean (SD)) was 1.4 (0.4) in patients with, and 2.6 (0.6) in patients without significant stenosis in the RCA (%diameter stenosis > 75%, P < 0.001). Using the cutoff value 2.0 for CFVR in the RCA, its sensitivity and specificity in detecting significant stenosis in the RCA were 88% and 91%, respectively. CONCLUSION: CFVR measurement in the postero-descending coronary artery by contrast enhanced TTDE is a new, noninvasive method to detect significant stenosis in the RCA.     

Detection of left main coronary artery stenosis by transesophageal color Doppler and two-dimensional echocardiography

Although transthoracic two-dimensional echocardiography can detect dilation of the coronary arteries, the reliability of this technique in the detection of coronary artery stenosis is still doubtful. The purpose of this study was to test the ability of newly developed biplane transesophageal color Doppler and two-dimensional echocardiography in the detection of left main coronary artery stenosis. Blood flow in the left main coronary artery was detected in 57 of 67 (85%) patients by transesophageal color Doppler flow imaging. Using transesophageal two-dimensional echocardiography, adequate images of the full length of the left main coronary artery and identification of the bifurcation were obtained in 60 of 67 (90%) patients. Transesophageal echocardiography clearly showed significant (greater than or equal to 50%) narrowing of the coronary lumen in 10 of 11 patients (sensitivity, 91%) and insignificant narrowing or no abnormalities of the coronary lumen in the other 49 patients (specificity, 100%). The positive predictive accuracy for left main coronary artery disease was 100%, and the negative predictive accuracy was 98%. This preliminary study suggests that biplane transesophageal color Doppler and two-dimensional echocardiography appears to be a feasible noninvasive technique for imaging the left main coronary artery and detecting hemodynamically significant luminal obstruction.     

Coronary flow reserve of the angiographically normal left anterior descending coronary artery in patients with remote coronary artery disease

Coronary artery disease (CAD) has been suggested to alter coronary flow reserve (CFR; the ratio between hyperemic and baseline coronary flow velocities) not only in territories supplied by stenotic arteries but also in angiographically normal, remote regions. However, few data exist regarding the left anterior descending (LAD) coronary artery as the normal index artery. The influence of remote CAD on CFR of the angiographically normal LAD was evaluated with transthoracic Doppler ultrasound to measure CFR in the LAD during 90 seconds of venous adenosine infusion (140 microg/kg/min) in 122 subjects who were assigned to 1 group; group 1 comprised 49 controls without angiographically detectable CAD, and group 2 consisted of 73 patients with an angiographically normal LAD and remote CAD. Group 2 was divided into 4 subgroups: 16 patients with previous remote percutaneous coronary intervention (group 2A); 13 patients with significant remote stenosis (group 2B); 23 patients with previous remote myocardial infarction and percutaneous coronary intervention (group 2C); and 21 patients with previous remote myocardial infarction but no percutaneous coronary intervention (group 2D). CFR in the LAD was not significantly different in groups 1 and 2 (3.08 +/- 0.61 and 3.03 +/- 0.69, respectively, p = NS). Decreased ejection fraction and increased wall motion score index in patients with remote CAD (p < 0.00001) and multivessel CAD did not affect CFR in the LAD (group 2A 3.18 +/- 0.77; group 2B 3.05 +/- 0.65; group 2C 3.07 +/- 0.79; group 2D 2.86 +/- 0.50, respectively; F = 0.63, p = NS). In conclusion, CFR of an angiographically normal LAD is preserved in patients with remote CAD, even in the presence of previous remote myocardial infarction and wall motion abnormalities.     

Abnormal left ventricular early diastolic filling during dobutamine stress Doppler echocardiography is a sensitive indicator of significant coronary artery disease

Objectives. This study was designed to assess changes in Doppler indexes of left ventricular ejection and filling in response to high dose (40 μg/kg body weight per min) dobutamine stress and their utility in detection of coronary artery disease compared with that of new wall motion abnormalities.Methods. Ten patients with a low likelihood of coronary artery disease served as a control group, and 23 patients with documented single-vessel coronary artery disease underwent baseline and peak dobutamine echocardiographic and Doppler studies.Results. In both groups dobutamine induced similar increases in heart rate and systolic blood pressure. During the test, 14 patients had new wall motion abnormalities, 13 had angina, and 7 had electrocardiographic ST segment changes. No markers of ischemia occurred in the control subjects. Dobutamine induced qualitatively similar changes from baseline to peak dobutamine stress in control subjects and patients in peak aortic velocity (46% vs. 42%, p = NS), average aortic acceleration (61% vs. 43%, p = 0.03) and systolic time-velocity integral (7% vs. 2%, p = NS). Dobutamine caused marked increases in control subjects and decreases in patients in peak early filling velocity (E) (33% vs. −22%, p < 0.0001) and average E acceleration (76% vs. −28%, p < 0.0001). The response of Doppler early filling indexes to dobutamine stress was abnormal in all patients. There was no overlap in the percent change from baseline to peak dobutamine stress between control subjects and patients for E and E acceleration.Conclusions. During dobutamine stress testing, an abnormal response of Doppler indexes of left ventricular early filling is a more sensitive marker of significant single-vessel coronary disease than are new wall motion abnormalities, and it is far superior to the response of Doppler ejection variables as a predictor of coronary artery disease.     

Sensitivity and specificity of nuclear phase analysis versus ejection fraction in coronary artery disease

Phase standard deviation (SD) and skew characteristics of the first Fourier harmonic of equilibrium radionuclide volume curves were examined and compared during rest and during supine bicycle exercise with ejection fraction (EF) changes and the development of ischemia in 17 control subjects and in 2 groups of patients (n = 57) with coronary artery disease (CAD). Group I comprised 37 patients with CAD; IA was a subgroup of 20 patients with previous myocardial infarction (MI) and IB a subgroup of 17 patients with CAD without MI (all with coronary stenosis greater than 75% diameter narrowing). Group II comprised 20 patients with CAD who had undergone coronary bypass surgery. In the Group I subjects, phase SD was the most sensitive indicator of CAD at rest (Group I, 56%; Group IA, 70%, and Group IB, 29%), and the EF was the most sensitive indicator at submaximal (Group I, 78%; Group IA, 86%, and Group IB, 64%) and maximal exercise (Group I, 70%; Group IA, 93%, and Group IB, 53%). When phase SD and skewness were combined with EF changes, little increase in sensitivity occurred in Group I (rest 61%, submaximal exercise 88% and maximal exercise 76%). The results from Group II subgroups were qualitatively similar to those observed with Group I subgroups. These data reveal a marginally improved sensitivity for detection of CAD during supine bicycle radionuclide ventriculography when phase measurements were added to changes in global EF values.