Cut-off value of coronary flow velocity reserve by transthoracic Doppler echocardiography for the assessment of significant donor left anterior descending artery stenosis in patients with spontaneously visible collaterals

We evaluated the influence of collateral circulation on a donor left anterior descending artery and an appropriate cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis. Measurement of coronary flow velocity reserve by transthoracic Doppler echocardiography provides noninvasive assessment of significant left anterior descending artery stenosis. The cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis has not been well studied. We retrospectively examined 64 patients who had no significant left anterior descending artery stenosis and who had other coronary artery stenosis. Seventeen patients had collaterals from the left anterior descending artery (group A) and 47 patients did not have collaterals (group B). We prospectively examined 23 consecutive patients who had collaterals from the left anterior descending artery to other coronary arteries. Eight patients had a significant donor left anterior descending artery stenosis. Coronary flow velocity reserve assessment was performed by transthoracic Doppler echocardiography in the 2 protocols. Coronary flow velocity at baseline in group A was significantly higher than that in group B. Coronary flow velocity reserve in group A was significantly lower than that in group B (2.6 +/- 0.8 vs 3.2 +/- 0.9, p < 0.05). Coronary flow velocity during hyperemia and coronary flow velocity reserve were significantly lower in patients with significant stenosis. A cut-off value of 2.0 of coronary flow velocity reserve had a sensitivity of 88% and a specificity of 93% for the diagnosis of significant donor left anterior descending artery stenosis. In conclusion, coronary flow velocity reserve of a donor left anterior descending artery was decreased by the presence of collaterals. However, a cut-off value < 2.0 was appropriate for the diagnosis of significant donor left anterior descending artery stenosis in a population that included patients with collaterals.     

Non-invasive evaluation of coronary reserve. Assessment of coronary reserve in patients with coronary artery disease by transesophageal-Doppler echocardiography

We assessed coronary flow reserve using transesophageal Doppler echocardiography in patients with coronary artery disease. The study included 33 coronary artery disease patients who were undergoing coronary arteriography. The blood flow velocities of the left anterior descending artery before and after intravenous infusion (0.56 mg/min for 4 min) of dipyridamole were recorded using transesophageal Doppler echocardiography. Fourteen normal healthy individuals, matched for age, served as a control group. The index of coronary flow reserve, i.e. the ratio of dipyridamole to baseline maximum diastolic velocity, was calculated. Maximal coronary flow reserve in coronary artery disease patients was significantly lower than in the control group (1.4+/-0.2 vs. 2.8+/-0.3, P<0.001). The coronary artery disease patients were classified into three groups: Group A included 10 patients with <50% left anterior descending artery stenosis; Group B included seven patients with 50-69% left anterior descending artery stenosis; 16 patients with >70% left anterior descending artery stenosis constituted Group C. The maximum coronary flow reserve was significantly different for A vs. B and A vs. C. (A, 1.77+/-0.18; B, 1.51+/-0.1; C, 1.28+/-0.24). A strong and significant correlation was found between the maximum coronary flow reserve and the degree of proximal left anterior descending artery stenosis (r=0.78, P<0.001). Coronary artery disease patients without left anterior descending artery stenosis on the arteriogram exhibited lower maximum coronary flow reserve compared to the control subjects (1.78+/-0.19 vs. 2.8+/-0.3, P=0.000).     

Coronary blood flow reserve measured by contrast media injection depends on myocardial viability

Coronary blood flow reserve may be affected by several physiological variables besides hydraulic impediment to flow. A hyperaemic response induced by hyperosmolar radiopaque contrast medium was recorded in the left anterior descending and left circumflex arteries with a steerable pulsed Doppler system in four patients with Q wave anterior myocardial infarction chronic scar and non-stenotic coronary arteries. Resting flow velocities were similar in both arteries. The magnitude of the hyperaemic response induced by contrast media in the circumflex artery (mean flow velocity increase from 5.9 +/- 2.5 baseline to 12.2 +/- 0.6 cm s-1 at peak flow, P less than 0.05) was almost twice that induced in the left anterior descending artery (mean flow velocity increase from 6.1 +/- 2.2 baseline to 7.4 +/- 2.6 cm s-1 at peak flow, P = N.S.). The peak flow to baseline flow velocities ratios were 1.22 +/- 0.15 in the left anterior descending artery vs 2.23 +/- 0.75 in the circumflex artery. Thus when a post-myocardial infarction chronic scar is supplied by a non-stenotic coronary artery, the coronary blood flow hyperaemic response to contrast media-induced transient ischaemia is decreased, suggesting that coronary blood flow reserve depends on a myocardial metabolic stimulus which is impaired by ischaemic cell death.     

Alterations of phasic coronary artery flow velocity in humans during percutaneous coronary angioplasty.

BACKGROUND AND OBJECTIVES. Studies using Doppler catheters to assess blood flow velocity and vasodilator reserve in proximal coronary arteries have failed to demonstrate significant improvement immediately after coronary angioplasty. Measurement of blood flow velocity, flow reserve and phasic diastolic/systolic velocity ratio performed distal to a coronary stenosis may provide important information concerning the physiologic significance of coronary artery stenosis. This study was designed to measure these blood flow velocity variables both proximal and distal to a significant coronary artery stenosis in patients undergoing coronary angioplasty. METHODS. A low profile (0.018-in.) (0.046-cm) Doppler angioplasty guide wire capable of providing spectral flow velocity data was used to measure blood flow velocity, flow reserve and diastolic/systolic velocity ratio both proximal and distal to left anterior descending or left circumflex coronary artery stenosis. These measurements were made in 38 patients undergoing coronary angioplasty and in 12 patients without significant coronary artery disease. RESULTS. Significant improvement in mean time average peak velocity was noted in distal coronary arteries after angioplasty (before 19 +/- 12 cm/s; after 35 +/- 16 cm/s; p less than 0.01). Increases in proximal average peak velocity after angioplasty were less remarkable (before 34 +/- 18 cm/s; after 41 +/- 14 cm/s; p = 0.04). Mean flow reserve remained unchanged after angioplasty both proximal (1.5 +/- 0.5 vs. 1.6 +/- 1; p greater than 0.10) and distal (1.6 +/- 1 vs. 1.5 +/- 0.8; p greater than 0.10) to a coronary stenosis. Before angioplasty, mean diastolic/systolic velocity ratio measured distal to a significant stenosis was decreased compared with that in normal vessels (1.3 +/- 0.5 vs. 1.8 +/- 0.5; p less than 0.01). After angioplasty, distal abnormal phasic velocity patterns generally returned to normal, with a significant increase in mean diastolic/systolic velocity ratio (1.3 +/- 0.5 vs. 1.9 +/- 0.6; p less than 0.01). Phasic velocity patterns and mean diastolic/systolic velocity ratio measured proximal to a coronary stenosis were not statistically different from values in normal vessels (1.8 +/- 0.8 vs. 1.8 +/- 0.5; p greater than 0.10) and did not change significantly after angioplasty (1.8 +/- 0.8 vs. 2.13 +/- 0.9; p greater than 0.10). CONCLUSIONS. Flow velocity measurements may be performed distal to a coronary stenosis with the Doppler guide wire. Phasic velocity measurements made proximal to a coronary stenosis differed from those in the distal coronary artery. Both proximal and distal flow reserve measurements made immediately after angioplasty were of limited utility. Changes in distal flow velocity patterns and diastolic/systolic velocity ratio appeared to be more relevant than the hyperemic response in assessing the immediate physiologic outcome of coronary angioplasty.     

Simultaneous measurement of coronary flow reserve by left anterior descending coronary artery Doppler and great cardiac vein thermodilution methods.

OBJECTIVES. The objective of this study was to compare left anterior descending coronary artery Doppler blood flow velocity and great cardiac vein thermodilution blood flow measurements of coronary flow reserve and submaximal coronary vasodilation in humans. BACKGROUND. Reported maximal coronary flow reserve values obtained with the coronary venous thermodilution method are lower than those obtained with other measurement methods. METHODS. Thermodilution measurements of great cardiac vein flow in 11 subjects were compared with simultaneous Doppler measurements of changes in left anterior descending coronary flow velocity after intracoronary administration of papaverine, nitroglycerin, iohexol and intravenous administration of dipyridamole. RESULTS. Coronary flow reserve (papaverine peak/rest flow ratio) was 3.7 +/- 1.7 (mean +/- SD) by the Doppler method and 2.0 +/- 0.7 by the thermodilution technique (p less than 0.001). Thermodilution flow changes were also smaller than Doppler-measured changes during submaximal vasodilation and during prolonged coronary dilation after dipyridamole administration. CONCLUSIONS. Coronary flow reserve and submaximal flow increases measured with the thermodilution method were consistently and substantially smaller than Doppler-derived measurements. This discrepancy has important implications for the comparison of coronary flow reserve measurements performed with the use of different techniques.     

Noninvasive assessment of significant right coronary artery stenosis based on coronary flow velocity reserve in the right coronary artery by transthoracic Doppler echocardiography

BACKGROUND: Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of coronary stenosis in the left anterior descending artery. However, the measurement of CFVR in the right coronary artery by TTDE has not yet been validated in a clinical study. OBJECTIVE: The aim of this study was to evaluate whether CFVR by TTDE can detect significant stenosis in the right coronary artery. METHODS: We studied 50 patients who underwent coronary angiography. Coronary flow velocity in the posterior descending branch of the right coronary artery (PD) was measured by TTDE both at baseline and during hyperemia induced by the intravenous infusion of adenosine triphosphate. CFVR was calculated as the hyperemia/baseline (average diastolic peak velocity). RESULTS: Adequate spectral Doppler recordings in the PD were obtained in 36 patients including 26 patients who were given an echocardiographic contrast agent to improve Doppler spectral signals. The study population was divided into 2 groups with (Group A;n = 11) and without (Group B;n = 25) significant stenosis in the right coronary artery. CFVR in Group A was significantly smaller than that in Group B (1.6+/-0.3versus2.5+/-0.4; P < 0.0001). The sensitivity of a CFVR of <2.0 for predicting the presence of significant stenosis in the right coronary artery was 91%, and the specificity was 88%. CONCLUSIONS: The measurement of CFVR in the PD by TTDE is useful for the noninvasive assessment of significant stenosis in the right coronary artery.     

Clinical significance of coronary flow reserve in hypertrophied heart: comparison with Doppler index, hemodynamics and plasma natriuretic peptide concentrations

OBJECTIVES: The relationship was investigated between coronary flow reserve and Doppler echocardiographic parameters, hemodynamic parameters and plasma natriuretic peptide concentrations in the hypertrophied heart. METHODS: The subjects were 19 patients with hypertrophied heart due to various etiologies and no significant coronary artery stenosis. All patients were in sinus rhythm. The left ventricular wall thickness, the E/A ratio in transmitral flow velocity pattern and the Doppler index were determined by Doppler echocardiography, and the plasma atrial and brain natriuretic peptide concentrations were measured. At cardiac catheterization, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were measured, and the coronary flow reserve was obtained by injecting intracoronary adenosine triphosphate into the left anterior descending artery using a Doppler guidewire. RESULTS: Coronary flow reserve in the patients was significantly lower than in 11 normal control subjects (2.50 +/- 0.76 vs 3.90 +/- 0.64, p < 0.001). There were no significant correlations between coronary flow reserve and the left ventricular wall thickness or the E/A ratio. The mean value of the Doppler index in the patients was 0.48 +/- 0.10 and there was a significant negative correlation between coronary flow reserve and the Doppler index (r = -0.73, p < 0.001). The correlation between coronary flow reserve and left ventricular end-diastolic pressure was not significant, but there was a significant negative correlation between coronary flow reserve and pulmonary capillary wedge pressure (r = -0.64, p < 0.01). There were significant negative correlations between coronary flow reserve and atrial (r = -0.62, p < 0.01), or brain natriuretic peptide concentrations (r = -0.56, p < 0.05). CONCLUSIONS: Coronary flow reserve may reflect overall cardiac performance evaluated by the Doppler index and plasma natriuretic peptide concentrations in the hypertrophied heart, and the measurement of coronary flow reserve may be useful for evaluating disease severity in patients with hypertrophied heart.     

Coronary Artery Shape and Flow Changes Induced by Myocardial Bridging

Changes in coronary shape and blood flow induced by myocardial bridging were analyzed in a 56-year-old patient with symptoms of unstable angina after the exclusion of other heart disease. Coronary angiography demonstrated a 1.8-cm long myocardial bridge in the middle part of the left anterior descending coronary artery. In systole, an eccentric compression of the artery occurred, resulting in a stenosis that occupied 86% of the diameter and 96% of the area. Intraluminal ultrasound was performed with a 20-MHz transducer in a 4.8-Fr catheter sheath (Boston Scientific Corp.) connected to an ultrasound console (Diasonics Inc.). A side saddle catheter was introduced into the left anterior descending coronary artery via a giant guiding catheter. A circular shape with typical systolic pulsation was seen in the proximal part of the artery (maximal and minimal diameters 3.6 mm and 3.5 mm, respectively). Distally an eccentric compression of the coronary artery was visualized, decreasing one diameter from 3.0 to 2.6 mm, whereas the orthogonal diameter remained constant at 3.3 mm. The myocardial bridge compressed 160°–180° of the circumference of the artery, leading to a change from a circular to an elliptical arterial shape. A delayed relaxation of the bridging was demonstrated. Only the proximal part of the vessel in the muscle bridge could be passed. Coronary flow was measured using a Doppler 3-Fr 20-MHz catheter (Millar Instruments Inc.) using a pulse repetition rate of 62.5 kHz. Coronary flow velocity was calculated in the proximal part of the left anterior descending coronary artery before and after intracoronary injection of 10 mg papaverine. Phasic coronary flow velocity increased from 14 to 21 cm/sec and mean flow from 6 to 13.5 cm/sec, yielding an estimated flow reserve of 1.5 and 2.2, respectively (normal > 3.0). Thus, intravascular and Doppler ultrasound are useful techniques for analyzing the effect of myocardial bridging on changes in coronary shape and blood flow. An eccentric compression of the coronary artery was visualized with delayed relaxation. Coronary flow reserve was reduced. Further studies in larger patient populations are necessary to demonstrate whether reduction of coronary flow reserve is, in general, related to delayed relaxation in diastole.     

Noninvasive assessment of coronary flow velocity reserve in left anterior descending artery adds diagnostic value to both clinical variables and dobutamine echocardiography: a study based on clinical practice.

AIMS: Our objective was to evaluate, in clinical practice, whether noninvasive assessment of coronary flow velocity reserve in left anterior coronary artery adds diagnostic information to both clinical variables and wall motion abnormalities derived from dobutamine stress echocardiography. METHODS AND RESULTS: We studied 130 patients who were scheduled for coronary angiography after undergoing dobutamine stress echocardiography. The same day, flow in left anterior descending artery was detected by transthoracic Doppler echocardiography. A Doppler signal of left anterior descending artery was detected in 110 patients (85%). We identified significant left anterior descending artery stenosis (>50% diameter stenosis) in 42 patients. Sensitivity and specificity of abnormal coronary flow velocity reserve (<2) to detect left anterior descending artery stenosis were 86% and 57%, respectively. Wall motion abnormalities had a sensitivity and specificity of 52% and 82%. After forcing the clinical and dobutamine stress echo variables into a regression model with three modeling steps, an abnormal coronary flow velocity reserve provided incremental information in predicting significant left anterior descending artery stenosis. CONCLUSION: An abnormal coronary flow velocity reserve by transthoracic Doppler echocardiography adds diagnostic value to both clinical data and variables derived from dobutamine stress echo to detect significant left anterior descending artery stenosis.     

Revascularization interventions in the left coronary artery system: transesophageal Doppler ultrasound study

AIM: To elucidate the role of evaluation of coronary reserve in coronary sinus by transesophageal doppler for assessment of efficacy of various revascularization interventions. MATERIAL AND METHODS: Patients with isolated stenoses of either left anterior descending or circumflex coronary artery subjected to stenting (n=14) and with two vessel disease subjected to bypass surgery (n=20). Dipyridamole was used as a stress agent. Coronary reserve was calculated as ratio of peak hyperemic to baseline antegrade coronary sinus blood flow velocity (CR(P)) and as ratio of hyperemic to baseline antegrade coronary sinus volume blood flow (CR(VBF)). RESULTS: In patients with atherosclerotic lesions in the system of left coronary artery normalization of CR(P) after stenting of single vessel stenoses and of CR(VBF) after bypass surgery in two vessel disease were markers of efficacy of revascularization with sensitivity 75 and 71%, respectively.     

A simplified method to measure coronary blood flow velocity in patients: validation and application of a Judkins-style Doppler-tipped angiographic catheter

To facilitate more rapid and safe measurement of coronary flow velocity reserve in patients, we developed a Judkins-style angiographic catheter tipped with a 20 MHz Doppler crystal. In 19 patients without coronary artery disease, resting and hyperemic (10 mg intracoronary papaverine) mean and phasic coronary flow velocity signals were measured with the Judkins-style and 2.5F intracoronary Doppler catheters at identical coronary loci. Mean coronary flow velocity at rest was similar (14 +/- 8, 10 +/- 7 cm/sec, p = ns), but was higher during hyperemia for the Judkins-Doppler (41 +/- 8 versus 32 +/- 14 cm/sec, p less than 0.05). Coronary flow velocity reserve, calculated as the ratio of mean velocity at rest to mean velocity following papaverine, was 3.3 +/- 1.4 and 3.7 +/- 1.2 units (p = ns) for the Judkins and intracoronary Doppler techniques, respectively (r = 0.801, p less than 0.001). The Judkins-style Doppler catheter technique permits flow velocity and coronary flow velocity reserve measurements that correlate strongly with those of the intracoronary catheter technique, facilitating safe, quick, and accurate assessment of coronary physiology.     

Coronary Artery Imaging with Transthoracic Doppler Echocardiography

Coronary artery imaging with transthoracic Doppler echocardiography is a simple and useful technique to diagnose significant coronary artery stenosis. The visualization of mosaic flow in the proximal left coronary artery provides a direct indication of the presence of significant stenosis at the corresponding site during routine echocardiography. Coronary flow velocity reserve (CFVR) has a high diagnostic accuracy and feasibility in detecting the presence of functionally significant coronary stenosis in the left anterior descending coronary artery (LAD) and in the right coronary artery. The measurement of CFVR in the LAD also provides prognostic information in patients with intermediate coronary stenosis. This review summarizes the utility of transthoracic coronary artery imaging.     

Detection of angiographic lesions in the left anterior descending coronary artery by transthoracic Doppler echocardiography: usefulness of non-invasive assessment of coronary flow reserve

INTRODUCTION: We evaluated the feasibility of detecting blood flow in the left anterior descending coronary artery and the usefulness of measuring coronary flow reserve to diagnose significant coronary artery disease, both by means of transthoracic Doppler echocardiography using a high-frequency transducer and echo-contrast agent. PATIENTS AND METHOD: We studied 107 patients who were scheduled for coronary arteriography for known or suspected ischemic heart disease. A Doppler signal was recorded by a pulsed wave in the distal left anterior descending artery at baseline and after dipyridamole infusion. An echo-contrast agent was administered to all patients. A coronary flow reserve equal to or higher than 1.7 was considered normal. RESULTS: We recorded Doppler signals in the left anterior descending coronary artery of 83 patients (78%). Significant stenosis of the left anterior descending coronary artery was observed in 24 out of 83 patients (29%). The prevalence of significant stenosis was higher (62 vs 29%; p = 0.006) in patients in which no Doppler signal was detected. The sensitivity, specificity, and accuracy of abnormal coronary flow reserve in detecting significant stenosis of the left anterior descending coronary artery were 87, 74 and 78%, respectively. CONCLUSIONS: The measurement of coronary flow reserve by transthoracic Doppler echocardiography using a high-frequency transducer and echo-contrast agent is a feasible, widely available, and accurate method for detecting significant stenosis of the left anterior descending coronary artery.     

Impairment of coronary flow reserve in orthotopic cardiac transplant recipients with minor coronary occlusive disease.

OBJECTIVE--Coronary occlusive disease is the major long-term complication after cardiac transplantation. The relation between minor angiographic abnormalities and myocardial perfusion has not been previously assessed in a large number of cardiac transplant patients. DESIGN--Prospective study. Coronary flow reserve was measured with an intracoronary Doppler flow probe in the proximal left anterior descending coronary artery in each patient. A dose of intracoronary papaverine producing maximal vasodilation was then administered. SETTING--A regional cardiothoracic centre and a supraregional transplant unit. PATIENTS--Seven patients with chest pain but normal coronary anatomy (controls), and 61 cardiac transplant patients between three months and 10 years after operation (median 4.5 years). Twenty one cardiac transplant patients had angiographic evidence of minor coronary occlusive disease (mean (SD) percentage stenosis diameter 23% (6%)) in a primary or secondary coronary vessel (group 1), with 12 of these in the left anterior descending coronary artery (stenosis diameter (mean (SD) 24% (8%)). The remaining 40 transplant patients had normal coronary angiograms (group 2). MAIN OUTCOME MEASURE--Coronary flow reserve was defined as the ratio of the peak flow velocity after papaverine to the resting flow velocity. RESULTS--Group 1 patients had a noticeably impaired coronary flow reserve (2.6 (1.1)) compared with control patients (3.9 (0.4), p = 0.05) and, after adjusting for year after operation, compared with group 2 patients (3.8 (1.0), p < 0.001). No other variables were associated with a reduction in coronary flow reserve. Mean resting flow velocity was similar in all three groups (controls, 7.4 (4.6) cm/s; group 1, 7.5 (5.9) cm/s; and group 2, 7.3 (3.9) cm/s). Mean peak flow velocity response to papaverine was reduced in group 1 patients (18.1 (13.5) cm/s) relative to group 2 patients (27.5 (15.4) cm/s, p = 0.05) but not controls (28.4 (15.1) cm/s, p = 0.1). CONCLUSIONS--Coronary flow reserve and the peak flow response to the coronary vascular smooth muscle relaxant papaverine are impaired in cardiac transplant patients with minor coronary occlusive disease. This disturbance of cardiac microvascular function may contribute to the late morbidity and mortality seen in cardiac transplant patients with coronary occlusive disease.     

Subselective measurement of coronary blood flow velocity using a steerable Doppler catheter

The accuracy of coronary arteriography to predict obstruction to coronary blood flow has recently been questioned. Assessment of coronary hemodynamic variables and vasodilator reserve may provide more reliable information regarding the significance of coronary stenosis. To provide a clinically safe and reliable method of measuring coronary blood flow velocity and coronary flow reserve, a 3F steerable Doppler catheter capable of subselective placement in the coronary circulation was developed and validated in an animal model. Coronary blood flow velocity measured with the catheter correlated with simultaneous measurements by a previously validated external cuff type Doppler probe (r = 0.97), coronary sinus flow collections (r = 0.78) and femoral artery flow collections (r = 0.96). The extravascular Doppler cuff measurements of rest flow velocity and vasodilator reserve were not significantly different with or without the catheter in the artery, indicating that the Doppler catheter caused no obstruction to blood flow. The Doppler catheter has recorded stable and reproducible signals without complications in 28 patients, including 62 separate arterial cannulations. Thus: 1) the 3F Doppler coronary catheter is nonobstructing, steerable and safe; 2) there is an excellent correlation of blood flow velocity with volume collections; and 3) the catheter provides a reliable method of determining coronary blood flow velocity and coronary vasodilator reserve.     

Evaluation of coronary flow reserve using Doppler guide wire in patients with ampulla cardiomyopathy: three case reports

Coronary flow velocity recordings were obtained in three patients with ampulla (Takotsubo) cardiomyopathy using Doppler guide wire. Immediately after admission, coronary angiography demonstrated no significant stenosis and normal coronary flow in the epicardial coronary artery. Left ventriculography showed abnormal wall motion of the left ventricle mimicking ampulla shape in all patients. The coronary flow velocity pattern was normal, but coronary flow reserve of the left anterior descending coronary artery was decreased by adenosine administration in all patients. The coronary flow reserve in the left circumflex and right coronary artery also decreased. Cardiac catheterization was performed during the follow-up period in two patients. Left ventriculography revealed almost normal wall motion of the left ventricle. The coronary flow reserve normalized in one patient.     

Postinfarctional remodeling: increased dye intensity in the myocardial risk area after angioplasty of infarct-related coronary artery is associated with reduction of ventricular volumes

OBJECTIVES: We sought to evaluate if angiographic dye videointensity of the risk area during percutaneous transluminal coronary angioplasty (PTCA) of the infarct-related artery (IRA) relates to remodeling. BACKGROUND: Poor reflow after myocardial infarction (MI) predicts worse ventricular remodeling. METHODS: Fifty-three patients with a first anterior MI and isolated disease of the left anterior descending (LAD), who underwent "primary" (n = 14), "rescue" (n = 7) or "late" (after 10 +/- 4 days, n = 32) PTCA, were retrospectively selected. In 10 patients prospectively collected, we assessed Doppler flow velocities and Doppler flow reserve (DFR), relating them to the videointensity technique. Coronary stenosis and TIMI flow were determined, and echocardiographic volumes (end-diastolic and end-systolic volume indexes) and regional asynergy were computed before hospital discharge (baseline) and at six months. Assuming higher peak videointensity reflects greater myocardial blood volume, a 1- to 5-point (poor-optimal) perfusion scale was devised. RESULTS: The correlation of Doppler peak velocity and DFR with videointensity was significant (r = 0.58, p = 0.007 and r = 0.71, p < 0.001, respectively). Patients were subdivided into group A (increased videointensity post-PTCA > or = 1.5 points, n = 29) and group B (unchanged videointensity, n = 24). Analysis of variance showed a time-group interaction for end-diastolic volume index (-4.6 +/- 23% vs. +22 +/- 22%, p = 0.003) and end-systolic volume index (-3.05 +/- 11.1% vs. +4.1 +/- 12.5%, p = 0.027). There was no interaction for changes in LAD stenosis (p = 0.39) and TIMI flow after PTCA (p = 0.27), or regional asynergy at six months (p = 0.31). CONCLUSIONS: Angiographic dye videointensity in the risk area correlates with Doppler peak velocity and DFR, and its increase after PTCA of IRA has a limiting effect on ventricular volumes, independent of coronary stenosis resolution, changes in Thrombolysis In Myocardial Infarction (TIMI) flow or extent of regional asynergy.     

Coronary flow reserve in angiographically normal coronary arteries with one-vessel coronary artery disease without traditional risk factors.

AIMS: Reduced coronary flow reserve has been reported in patients with traditional risk factors, in particular hyperlipidaemia, despite angiographically normal coronary arteries. However, it is recognized that traditional risk factors do not explain the presence of coronary atherosclerosis in a large proportion of patients. The aim of this study was to assess whether coronary flow reserve is preserved in the myocardium supplied by normal coronary arteries in patients with one-vessel coronary artery disease without traditional risk factors. METHODS AND RESULTS: Positron emission tomography using [13N]ammonia was performed at baseline and after intravenous dipyridamole administration (0.56 mg x dl(-1)over 4 min) in 30 subjects: six patients with ischaemia on effort, no myocardial infarction, and isolated left anterior descending coronary artery stenosis without traditional risk factors (coronary artery disease patients without risk factors, aged 59+/-13), five patients with ischaemia on effort, no myocardial infarction, and isolated left anterior descending coronary artery stenosis with multiple risk factors (coronary artery disease patients with risk factors, aged 69+/-7), 11 age-matched controls (aged 58+/-6), and eight healthy young volunteers (aged 34+/-4). Myocardial blood flow calculated in the myocardium supplied by normal coronary arteries in the coronary artery disease patients was compared with those of the two control groups. Coronary flow reserve was defined as the ratio of hyperaemic blood flow after dipyridamole infusion to baseline blood flow. Although coronary flow reserve in the coronary artery disease patients with risk factors was significantly lower than that in the age-matched controls (1.62+/-0.37, 2.58+/-0.71, P=0.0428), coronary flow reserve in the coronary artery disease patients without risk factors was similar to that in the age-matched controls (2.54+/-0.17 vs 2.58+/-0.71, P=ns). CONCLUSION: Coronary flow reserve is preserved in regions supplied by angiographically normal coronary arteries with one-vessel coronary artery disease without traditional risk factors.     

Quantitative assessment of harmonic power Doppler myocardial perfusion imaging with intravenous Levovist in patients with myocardial infarction: comparison with myocardial viability evaluated by thallium-201 single-photon emission computed tomography and coronary flow reserve.

BACKGROUND: Intravenous myocardial contrast echocardiography with harmonic power Doppler imaging is a novel technique for assessing myocardial perfusion. AIMS: The aim of this study was to quantitatively assess myocardial perfusion by harmonic power Doppler imaging in patients with a previous myocardial infarction and compare myocardial contrast echocardiography results with myocardial viability evaluated by thallium-201 single-photon emission computed tomography ((201)Tl-SPECT) and the results of Doppler flow measurement of coronary flow velocity reserve. METHODS: Twenty-three patients with anterior myocardial infarction who were scheduled for adenosine stress (201)Tl-SPECT underwent myocardial contrast echocardiography with harmonic power Doppler imaging. Harmonic power Doppler imaging was performed at rest and during adenosine infusion (0.15 mg/kg/min) using an intravenous infusion of Levovist. The peak colour pixel intensity ratios of the risk area to the control area were used for quantitative analysis of myocardial perfusion by harmonic power Doppler imaging. Coronary blood flow velocity was measured using Doppler-tipped guidewire in the distal portion of left anterior descending artery and coronary flow velocity reserve was calculated. RESULTS: In patients with myocardial viability assessed by (201)Tl-SPECT, pixel intensity ratios both at rest and during hyperaemia were significantly higher compared with those in patients without myocardial viability (at rest: 0.62 +/- 0.28 vs 0.37 +/- 0.17, P=0.038, during hyperaemia 0.72 +/- 0.19 vs 0.40 +/- 0.18, P=0.003). Coronary flow velocity reserve was significantly different between two groups (2.35 +/- 0.43 vs 1.49 +/- 0.53, P <0.01). CONCLUSIONS: Quantitative assessment of microvascular integrity by harmonic power Doppler imaging corresponds to the evaluation of the microcirculation by coronary flow velocity reserve.     

Early impairment of coronary flow reserve and increase in minimum coronary resistance in borderline hypertensive patients

OBJECTIVE: To evaluate relations between coronary flow velocity and myocardial oxygen demand at rest, as well as coronary vasodilator capacity and flow reserve, in asymptomatic subjects with borderline hypertension as compared to normotensive controls and patients with sustained high blood pressure (HBP) and without left ventricular hypertrophy (LVH). SUBJECTS AND METHODS: Forty-two asymptomatic males were studied: 13 healthy normotensive volunteers; 12 subjects with borderline HBP and 17 asymptomatic subjects with sustained systemic hypertension. Coronary flow velocity in left anterior descending artery and coronary flow reserve were assessed by transesophageal echo-doppler at baseline and during intravenous adenosine infusion. Left ventricular mass, peak systolic wall stress (PSWS; Pa), and midwall fractional shortening (MFS; %) were obtained from M-mode images of the left ventricle in transthoracic long-axis view and in transesophageal transgastric view. RESULTS: Coronary flow velocity at baseline was not significantly different in the three groups, despite significantly higher rate-pressure product (RPP) in the hypertensive groups as compared with controls. Only in control subjects, was resting coronary flow velocity significantly correlated with RPP (y = 4279 + 200x, r = + 0.58, P < 0.05) and PSWS (y = 17.2 + 5.1 x, r = + 0.62, P < 0.05). Coronary reserve was 3.5 +/- 0.65 in controls and significantly lower (P < 0.05) in borderline hypertensive (2.87 +/- 0.46) and in sustained hypertensive subjects (2.66 +/- 0.56). Minimum coronary resistance was significantly increased in both hypertensive groups (1.30 +/- 0.29 and 1.39 +/- 0.48 mmHg/s per cm) as compared to normotensive controls (0.93 +/- 0.20 mmHg/s per cm, P < 0.01). CONCLUSIONS: In asymptomatic subjects with borderline hypertension and without LVH, a significant reduction in coronary flow reserve is already detectable and appears almost entirely related to an impaired coronary vasodilator capacity rather than to an increased myocardial oxygen demand.