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.     

Incremental diagnostic value of ultrasonographic assessment of coronary flow reserve with high-dose dipyridamole in patients with acute coronary syndrome

BACKGROUND: Coronary flow reserve (CFR) assessment by transthoracic Doppler echocardiography has been found to be useful in subjects with suspected coronary artery disease. An important clinical question is whether such technique can be successfully applied in patients admitted to the coronary care unit with an acute coronary syndrome to detect a significant left anterior descending (LAD) disease. METHODS: One hundred fifty-nine patients with acute coronary syndrome (93 patients with unstable angina, 66 with acute inferior or lateral myocardial infarction) were included in the present analysis. Patients underwent a high-dose dipyridamole stress (0.84 mg/kg) with combined assessment of CFR in the LAD and regional wall motion. Blood flow velocities were recorded in the mid-distal portion of the LAD using a digital ultrasonographic system and CFR was calculated as the ratio of hyperemia-induced peak diastolic velocity to resting peak diastolic flow velocity. All patients underwent coronary angiography and a significant LAD stenosis was classified for lumen narrowing > or = 70%. RESULTS: Adequate Doppler recordings in the LAD were obtained in 92% of patients. A contrast agent was used in the 39% of examinations. No major adverse reaction occurred in any patient. A receiving operating characteristic curve showed that a CFR value < 1.9 had a sensitivity of 85%, a specificity of 87%, a positive predictive value of 71%, a negative predictive value of 94% and a diagnostic accuracy of 86% for identifying a significant LAD stenosis. The area under the receiving operating characteristic curve computed for CFR was significantly higher than for wall motion score index (p < 0.001). In a stepwise forward, multiple logistic regression analysis, both CFR (OR = 4.8, 95% C.I. 3.7-5.3; p < 0.00001) and the wall motion score index for the LAD territory (OR = 4.2, 95% C.I. 2.6-6.8; p < 0.0001) were independent determinants of LAD stenosis > or = 70%. CONCLUSION: Early assessment of CFR by transthoracic Doppler echocardiography is feasible and safe and provides additional information to identify subjects with acute coronary syndrome and significant LAD stenosis.     

Serial analysis of regional left ventricular wall motion by two-dimensional echocardiography in patients with coronary artery enlargement after Kawasaki disease.

OBJECTIVES. This study was designed to assess the temporal relation between early coronary artery abnormalities and left ventricular function in Kawasaki disease. BACKGROUND. Although late segmental wall motion abnormalities may be seen in patients with Kawasaki disease who have coronary artery stenosis, the impact of early coronary artery abnormalities is unclear. METHODS. Regional left ventricular wall motion was assessed by two-dimensional echocardiography in 18 patients with Kawasaki disease and echocardiographic evidence of coronary artery enlargement at 3 weeks and 3 months and at either 6 or 12 months after the onset of fever. Four patients had a persistent left coronary artery aneurysm, four had regression of their aneurysm, two had persistent left coronary artery ectasia and eight had regression of ectasia. Left ventricular wall motion was assessed by measuring regional area change in parasternal and apical views. After planimetry of an end-systolic and an end-diastolic frame, the ventricle was divided into eight equal segments and the percent area change was calculated. A floating system correcting for translation and rotation was applied. The measurements in the patient group were compared with values previously obtained in 55 normal age-matched infants and children. RESULTS. A transient regional wall motion abnormality 3 and 6 months after the onset of fever was discovered in the inferolateral wall of one patient with a persistent left coronary artery aneurysm. One patient with regression of coronary artery ectasia had a persistent wall motion abnormality in the anterolateral left ventricular wall. There was no correlation between the extent of coronary artery enlargement and the presence or absence of wall motion abnormalities. CONCLUSIONS. These early changes are most likely secondary to associated myocarditis rather than coronary artery abnormalities.     

Prediction of coronary artery disease by left ventricular regional wall motion abnormalities in patients with stenosis of the aortic valve

To identify predictive factors for coronary artery disease in patients with stenosis of the aortic valve the clinical histories, haemodynamic measurements, biplane contrast left ventriculograms, and coronary angiograms of 83 consecutively catheterised patients with valvar aortic stenosis were examined retrospectively. The mean (SD) age was 66.4 (9.1) years and 78% were men. Fifty five patients had significant coronary artery disease (greater than or equal to 50% diameter narrowing). Forty five (82%) of 55 patients with and 23 (82%) of 28 patients without coronary disease had angina. Heart failure occurred in a third of the patients; these patients were on average older, were more likely to be female, and had lower ejection fractions and cardiac outputs than patients in whom failure did not occur. Calculated valve area, transvalvar gradient, and left ventricular end diastolic pressure did not discriminate between patients with and without coronary disease. Syncope was less common than angina and heart failure and was associated with significantly lower valve areas and higher gradients than those found in patients without syncope. Left ventricular regional wall motion abnormalities were equally common in the groups with and without angina and predicted coronary artery disease with 94% accuracy. The absence of regional wall motion abnormality was an insensitive marker of normal coronary arteries as 45% of such patients had coronary disease. Five of the 83 patients had significant coronary disease without angina or regional wall motion abnormality. In patients with aortic stenosis angina did not predict the presence of coronary artery disease; therefore, it is advisable to have the results of coronary angiography before aortic valve replacement in a population such as this. Two of the patients with heart failure and severe aortic stenosis had regional wall motion abnormality with normal coronary arteries. Thus in some patients left ventricular failure produced by increased afterload may itself be a cause of left ventricular regional wall motion abnormality.     

Prediction of coronary artery disease by left ventricular regional wall motion abnormalities in patients with stenosis of the aortic valve.

To identify predictive factors for coronary artery disease in patients with stenosis of the aortic valve the clinical histories, haemodynamic measurements, biplane contrast left ventriculograms, and coronary angiograms of 83 consecutively catheterised patients with valvar aortic stenosis were examined retrospectively. The mean (SD) age was 66.4 (9.1) years and 78% were men. Fifty five patients had significant coronary artery disease (greater than or equal to 50% diameter narrowing). Forty five (82%) of 55 patients with and 23 (82%) of 28 patients without coronary disease had angina. Heart failure occurred in a third of the patients; these patients were on average older, were more likely to be female, and had lower ejection fractions and cardiac outputs than patients in whom failure did not occur. Calculated valve area, transvalvar gradient, and left ventricular end diastolic pressure did not discriminate between patients with and without coronary disease. Syncope was less common than angina and heart failure and was associated with significantly lower valve areas and higher gradients than those found in patients without syncope. Left ventricular regional wall motion abnormalities were equally common in the groups with and without angina and predicted coronary artery disease with 94% accuracy. The absence of regional wall motion abnormality was an insensitive marker of normal coronary arteries as 45% of such patients had coronary disease. Five of the 83 patients had significant coronary disease without angina or regional wall motion abnormality. In patients with aortic stenosis angina did not predict the presence of coronary artery disease; therefore, it is advisable to have the results of coronary angiography before aortic valve replacement in a population such as this. Two of the patients with heart failure and severe aortic stenosis had regional wall motion abnormality with normal coronary arteries. Thus in some patients left ventricular failure produced by increased afterload may itself be a cause of left ventricular regional wall motion abnormality.     

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.     

Prognostic value of coronary flow reserve in medically treated patients with left anterior descending coronary disease with stenosis 51% to 75% in diameter

According to American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions 2005 guidelines on percutaneous intervention, intracoronary physiologic measurement in the assessment of effects of intermediate coronary stenoses in patients with anginal symptoms is a class IIa indication. This study assessed the additional prognostic value of Doppler echocardiographically derived coronary flow reserve (CFR) in patients with single-vessel disease and intermediate stenosis severity. We enrolled 86 patients (44 men; 66 +/- 10 years of age) with angiographically assessed single-vessel coronary artery disease of the left anterior descending coronary artery (LAD) with quantitatively assessed diameter stenosis severity 50% to 75%. All patients underwent dipyridamole (up to 0.84 mg/kg over 6 minutes) stress echocardiography with wall motion analysis by 2-dimensional echocardiography and CFR evaluation of the affected artery by Doppler. All patients were followed up for a median of 14 months (first quartile 10, third quartile 18) after diagnostic coronary angiography (without percutaneous intervention for a clinically driven decision). Mean diameter stenosis of the LAD was 58 +/- 10%. Mean CFR of the LAD was 2.09 +/- 0.5. Regional wall motion abnormality at peak stress was present in 17 patients. During follow-up, 24 events occurred: 6 nonfatal ST-elevation myocardial infarctions and 18 non-ST-elevation myocardial infarctions. Thirty-month spontaneous event-free survival was higher in patients with normal CFR and lower in patients with decreased CFR (86% vs 30%, p = 0.0001). At Cox analysis, a CFR <2 (hazard ratio 24.2, 95% confidence interval 3.2 to 179.7, p = 0.002) was the only independent prognostic predictor of outcome. In conclusion, in medically treated patients with single-vessel disease of intermediate severity, decreased CFR is associated with a worse outcome.     

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.     

Dobutamine stress echocardiography: correlation with coronary lesion severity as determined by quantitative angiography.

This study was performed 1) to determine the ability of dobutamine stress echocardiography to detect stenoses in individual coronary arteries by utilizing a new model of coronary artery distribution; 2) to evaluate its ability to detect coronary artery stenosis with a minimal lumen diameter less than 1 mm; and 3) to correlate the heart rate at which a positive test result occurs with the severity of coronary artery disease. Eighty-five patients were identified who underwent both dobutamine stress echocardiography and quantitative coronary angiography. During incremental infusion of dobutamine, two-dimensional echocardiograms were obtained at rest, during low and peak stress and after stress. Echocardiograms were interpreted with use of a modified 16-segment model with an anteroinferior overlap scheme. The overall sensitivity of the technique for the detection of significant coronary artery disease (diameter stenosis greater than or equal to 50%) was 95%; specificity was 82% and accuracy 92%. The sensitivity for detection of individual coronary artery lesions did not differ significantly (p greater than 0.05) in the three major coronary artery distributions (79% left anterior descending, 70% left circumflex, 77% right coronary artery). Among 35 stenoses with a minimal lumen diameter less than 1 mm, the test result was positive in 30 (86%). Test results were correctly positive for 88%, 82% and 86% of stenoses in the left anterior descending, left circumflex and right coronary artery distributions, respectively. Multivessel disease was present in 11 of 16 patients with normal wall motion at rest who developed a wall motion abnormality at a heart rate less than 125 beats/min. The incidence of multivessel disease was statistically higher in patients with positive findings on a dobutamine stress echocardiogram at a heart rate less than or equal to 125/min. In conclusion, dobutamine stress echocardiography has high sensitivity and specificity for the detection and localization of coronary artery disease. Detection of stenosis in individual coronary arteries is improved in those lesions with a minimal lumen diameter less than 1 mm. Patients with a positive test result at a heart rate less than or equal to 125 beats/min have a high likelihood of multivessel coronary artery disease.     

Interobserver variability in coronary angiography.

Four experienced coronary angiographers (two radiologists and two cardiologists) independently assessed the location and degree of coronary artery stenosis, and the location and degree of left ventricular wall motion abnormalities in 20 coronary angiograms. Marked interobserver variability was noted in quantifying percent coronary artery stenosis and degree of left ventricular wall motion abnormalities. For example, in only 13/20 (65%) of the coronary angiograms did all observers agree about the significance of a stenosis (defined as greater than 50% in diameter luminal narrowing) in the proximal or mid left anterior descending coronary artery. In 3/20 (15%) angiograms there was disagreement by at least one observer about the significance of lesions noted in the main left coronary artery. The ventricle was divided into five segments and the degree of wall motion abnormality graded into six categories of increasing severity from normal to dyskinesis. There was a 42% mean disagreement among all four observers where a disagreement between observers was defined as any difference in grading wall motion abnormalities. Interobserver variability reveals a significant limitation of coronary angiography.     

The echo-dobutamine test for the diagnosis of myocardial ischemia. Study on 20 patients with normal kinetics at rest

We have assessed the value of dobutamine stress echocardiography for the diagnosis of myocardial ischemia in 20 consecutive patients referred for chest pain, without a previous myocardial infarction and with a normal left ventricular wall motion at rest. The test was considered positive when wall motion abnormalities appeared during dobutamine infusion (from 5 to a maximum of 40 micrograms/Kg/min). The results were compared to the % diameter stenosis (%DS) quantitatively measured on coronary arteriography. "Significant" coronary artery disease was defined as greater than or equal to 50% DS. No significant side effects occurred in any patients during the test. Transient wall motion abnormalities were detected in 8 of the 12 patients with significant coronary artery disease (sensitivity = 66%) and in 1 of the 8 patients without significant coronary artery disease (specificity = 88%). All the patients with false-negative dobutamine stress echocardiography had distal stenosis or stenosis in a collateral vessel; moreover, all the patients with true-positive dobutamine stress echocardiography had proximal (7 patients) or middle (1 patient) stenosis. The results of this study show that dobutamine stress echocardiography is a safe and feasible test for the noninvasive diagnosis of myocardial ischemia.     

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.     

Collateral vessels assessed by myocardial contrast echocardiography in patients with coronary artery lesions after Kawasaki disease

Summary Using myocardial contrast echocardiography (MCE), coronary arteriography, and thallium-201 myocardial imaging (TMI), we examined the characteristics and the role of collateral vessels in 35 patients with coronary artery lesions after Kawasaki disease. The male/female ratio was 25∶10. The patients' ages at examination ranged from 1.0 to 20.3 years (mean, 10.8 years). The age at onset of Kawasaki disease ranged from 0.3 to 11.6 years (mean, 2.6 years). The coronary artery lesions were: dilated lesions without coexistent stenotic lesions in 5 patients (14%), localized stenosis with less than 50% narrowing in 5 patients (14%), localized stenosis with 50% or more narrowing in 4 patients (11%), and obstructive lesions, such as occlusion and/or segmental stenosis, in 21 patients (60%). In the group with no stenotic lesions and the group with less than 50% localized stenosis, the perfusion area of the right coronary artery was 32.6±8.4% and that of the left coronary artery was 76.3±7.9%. The total perfusion area of the right and the left coronary arteries was 108.9±2.6%, which value was inversely correlated with age at examination (r=0.716,P=0.020). In the group with more than 50% localized stenosis, an increase in overlap areas detected by MCE, where a perfusion defect was seen on TMI, was not found, except in 1 patient with 99% stenosis. In the patients with obstructive lesions, development of collateral channels was better in the perfusion area of the occluded right coronary artery than in that of the occluded left coronary artery, and well developed collateral channels were significantly correlated with good wall motion. We conclude that overlapping perfusion occurs in younger rather than in older children without stenotic coronary systems and this may contribute to the good development of collateral circulation in infants and young children with coronary artery lesions after Kawasaki disease.     

Atrial pacing with two-dimensional echocardiography for evaluation of chest pain: comparison with thallium 201 scintigraphy

Atrial pacing was performed with two-dimensional (2-D) echocardiography and thallium 201 scintigraphy in 40 men with stable chest pain. Coronary angiography showed significant (one or more lesions greater than or equal to 50%) coronary artery disease (CAD) in 36 patients and no or insignificant CAD in 4. Two dimensional echocardiography showed a left ventricular wall motion abnormality (WMA) either at rest or with pacing in 28 (78%) patients with CAD, with 17 (47%) showing a new or worsened WMA with pacing. A thallium scan showing abnormality (reversible or fixed perfusion defect) was seen in 26 (72%) patients with CAD; 18 (50%) had a reversible defect. In all, 34 of the 36 patients with CAD (94%) had a WMA, a perfusion defect, or both (specificity 50%). Occurrence of both a WMA and a perfusion defect in individual segments ranged from 10 of 25 patients with septal abnormalities to 0 of 12 with abnormalities of the lateral segment. Sensitivity of 2-D echocardiography for identifying CAD in specific vessels was 81% for the left anterior descending (LAD) artery, 30% for the right coronary artery, and 20% for the circumflex artery (both p less than .001 compared with the LAD artery). Corresponding sensitivities for thallium 201 imaging were 54% (p less than .05 compared with 2-D echocardiography), 27%, and 8% (both p less than .05 compared with the LAD artery). When combined with atrial pacing, 2-D echocardiography and thallium 201 perfusion imaging are of similar value for diagnosing the presence of CAD in patients with stable chest pain. Two-dimensional echocardiography is superior to thallium 201 imaging for identifying the presence of significant CAD in the LAD artery, but both tests are limited in their ability to detect lesions of the right coronary or circumflex arteries.     

负荷超声心动图检测冠心病冠状动脉病变部位的临床研究

目的 对比分析冠状动脉疾病(CAD)心绞痛患者多巴酚丁胺负荷超声心动图(DSE)时节段性室壁运动异常(RWMA)与冠状动脉造影(CAG)的结果,以分析和判断其相关的冠脉病变。方法 入选临床诊断或可疑CAD患者38例,静息二维超声心动图(2DE)检查未见RWMA,CAG为单支冠脉病变,并于CAG前1周内进行DSE试验。结果 缺血相关冠脉为左前降支(LAD)时累及前间隔中段,前壁基段、中段和心尖段,后间隔心尖段;缺血相关冠脉为左旋支(LCx)时累及侧壁基段、中段和后壁基段、中段例数居多;缺血相关冠脉为右冠状动脉(RCA)时累及下壁基段和中段例数居多。DSE检测出单支病变中LAD、LCx和RCA的敏感性依次为:78.9％,33.3％和70.0％。在LCx和RCA病变时后壁基段、中段RWMA的发生率比较差异无显著性(P>0.05)。结论 DSE试验对于判断心肌缺血的相关冠脉病变有一定的临床价值。     

Transesophageal Doppler echocardiographic imaging and blood flow measurements for the diagnosis of stenotic left coronary arteries]

To evaluate the usefulness of transesophageal Doppler echocardiography (TEE) in diagnosing left coronary artery (LCA) stenosis, we studied 26 patients with 33 proximal LCA lesions, including 5 with lesions of the left main trunk (LMT), 21 proximal anterior descending arteries (LAD), 7 proximal circumflex arteries (LCx), and 20 with normal coronary arteries. We measured blood flow velocity along the LCA using the pulsed Doppler mode (PD) and obtained velocities at multiple neighboring sites in 13 normal coronary arteries and in 12 of 26 LMTs or LADs with lesions. In all 13 normals, peak velocity tended to decline towards the periphery. By contrast, in one LMT and 10 LADs with lesions, marked increase in peak velocity (1.7 to 3.9 times) was observed at the sites diagnosed as stenotic lesions by coronary angiography. Using two-dimensional echocardiography (2DE), 24 LMTs including 3 with lesions, 4 LADs including 3 with lesions and 13 LCxs including 4 with lesions were imaged. Among them, 3 LMT, one LAD and 2 LCx lesions were correctly diagnosed. The diagnostic ratio by both PD and 2DE was 60% for LMT (PD: 20%, 2DE: 60%), 48% for LAD (PD: 48%, 2DE: 5%) and 29% for LCx (PD: 0%, 2DE: 29%) lesions. In conclusion, TEE proved to be useful in diagnosing proximal LCA stenosis. The coronary flow measurement by PD especially has the potentiality for the diagnosis of proximal LAD stenosis.     

Usefulness of flow reserve in the left internal mammary artery to determine graft patency to the left anterior descending coronary artery

Two-dimensional Doppler echocardiography (DE) and intravascular Doppler-tipped guidewire (flowire) have been used to measure flow in aortocoronary conduits at rest and during hyperemia, but they have not been compared. We investigated which flow velocity parameters obtained with these 2 different techniques can predict left internal mammary artery (LIMA) graft patency. Twenty-nine patients with previous coronary artery bypass grafting referred for evaluation of symptoms of coronary artery disease were studied after cardiac catheterization using the flowire and DE. Proximal LIMA graft flow velocity was measured at rest and during hyperemia produced by 140 microg/kg/min of intravenous adenosine infusion over 6 minutes with both methods. Normal LIMA grafts and left anterior descending artery (LAD) distal to the anastomosis were present in 16 patients, whereas 13 had >70% graft or native vessel stenosis. The coronary flow velocity reserve (r = 0.79) and the diastolic-to-systolic velocity ratio during hyperemia (r = 0.73) correlated very well between the 2 techniques. Among the variables obtained with the 2 techniques, the intragraft coronary flow velocity reserve measured by both methods was the only independent predictor of graft/recipient LAD patency. This variable had a sensitivity and specificity of 86% at a cutoff point of 2.07 with the flowire method and 83% at a cutoff point of 1.54 with DE. The areas below the receiver-operating characteristic curves were 0.91 and 0.93, respectively. Coronary flow velocity reserve measurements obtained with DE appears a reliable noninvasive method for assessing LIMA graft and/or LAD distal to the anastomosis patency in patients after bypass surgery and correlate very well with those directly obtained by intravascular Doppler.     

Effects of captopril on regional segment motion during acute coronary occlusion.

The effects of captopril on myocardial segment function in different degrees of transient coronary occlusion were studied using ultrasonic dimension gauges in 15 open-chest dogs. The occlusion procedures (OP) were performed on the left anterior descending coronary artery (LAD) in eight dogs and on the left circumflex coronary artery (Cx) in seven dogs. To measure the changes in segment shortening in the subendocardium we used eight dogs (ischemic and control zones: four dogs LAD and four dogs Cx). To measure the changes in wall thickening we used seven dogs (ischemic and control zones: three dogs LAD and four dogs Cx). Total coronary OP lasting 1 min and partial OP (70-80%) lasting 1 min and 2 min 30 s, before and after captopril (0.25 mg/kg i.v.) were performed. Left ventricular pressure, dP/dt, coronary flow, and ECG were monitored. Total coronary OP (1 min) changed segment shortening (18% LAD; 14% Cx) and wall thickening (19% LAD; 18% Cx) to values of dyskinesis (-3% and -4% for shortening; -6% and -5% for thickening). Captopril improved regional function maintaining positive values for shortening (4% LAD; 3% Cx) and thickening (0.3% LAD; 4% Cx). Similar responses were obtained during partial OP and captopril. Results suggest that captopril produced a significant improvement in the regional function parameters affected by ischemia both in total and partial obstructions.     

Semi-quantitative planar scintigraphy using thallium 201 for detection and localization of coronary artery disease: correlation with coronary angiography.

Thallium 201 exercise redistribution planar myocardial perfusion scan using semiquantitative technique was performed in 80 symptomatic patients undergoing coronary angiography. Out of the 240 vessels studied by angiography, more than 70% luminal narrowing was detected in 87 vessels, borderline stenosis was found in 49 arteries and the remaining 104 vessels were normal. Thallium scan correctly identified the significant stenosis in 76 vessels and the absence of stenosis in 102 vessels. In addition, perfusion abnormality was found in relation with 21 vessels of borderline stenosis. The sensitivity and specificity of Thallium scan were estimated as 92% and 95% for left anterior descending artery (LAD), 79% and 98% for left circumflex artery (LCX), 88% and 100% for right coronary artery (RCA) and 87% and 98% for all coronary arteries combined together (ACA).     

Electrocardiographic and coronary arteriographic correlations during acute myocardial infarction

One hundred fifty-two patients underwent cardiac catheterization and coronary arteriography within 6.3 ± 6.0 hours from the onset of acute myocardial infarction (AMI). All had standard 12-lead electrocardiograms recorded within 1 hour of cardiac catheterization. The electrocardiographic abnormalities present were correlated with the infarctrelated artery as determined by coronary arteriography. ST-segment elevation was the most common finding in patients with the left anterior descending (LAD) or right coronary artery as the infarct-related artery. ST-segment depression was the most common abnormality in patients with the left circumflex (LC), artery as the infarct-related artery. A classic pattern of anteroseptal AMI was seen in 93% of all patients with the LAD as the infarct-related artery. A classic pattern of inferior AMI was seen in 53% of patients with right or LC narrowing taken as 1 group. The pattern of true posterior and isolated lateral wall AMI in the absence of classic changes in the inferior leads was highly specific and predictive of LC narrowing. In contrast, the pattern of an inferior wall AMI, in the absence of true posterior or lateral wall changes, was highly specific and predictive of right coronary artery narrowing. Fifty-six percent of patients with LC artery as the infarct-related artery presented with non-classic electrocardiographic abnormalities. The electrocardiographic patterns in patients with subtotal occlusions were similar to those of patients with total occlusions. Thus, the electrocardiogram obtained in the first few hours of AMI is reliable in localizing the LAD as the infarct-related artery. Certain patterns are specific but not sensitive in localizing the right coronary artery as opposed to the LC artery as the infarct-related artery. Presentation with signs and symptoms of AMI and a nonclassic electrocardiogram is suggestive of LC narrowing.