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.     

Effects of smoking on coronary blood flow velocity and coronary flow reserve assessed by transthoracic Doppler echocardiography

BACKGROUND: Smoking is a well-known risk factor for cardiovascular disease. Coronary blood flow velocity (CFV) can be measured directly with transthoracic Doppler echocardiography (TTDE) which is conducted immediately after smoking. PURPOSE: The purpose of this study was to evaluate the chronic and acute effects of smoking on coronary blood flow and coronary flow reserve (CFR) by the use of TTDE. METHODS: Healthy volunteers (11 smokers and 9 nonsmokers) with a mean age of 27 +/- 3 years were included. Smoking was abstained for at least 4 hours before the study. CFV was measured at the distal left anterior descending coronary artery by TTDE at baseline and during intravenous adenosine infusion (140 microg/kg per minute) in all participants. For smokers, CFV was measured immediately after consecutively smoking two cigarettes and during adenosine infusion. RESULTS: CFR and coronary vascular resistance index (CVRI) showed no significant difference between nonsmokers and smokers (CFR: 3.5 +/- 0.8 vs 3.6 +/- 0.6, P = ns, CVRI: 0.28 vs 0.28, P = ns) at baseline. CFR significantly decreased (3.6 +/- 0.6 to 2.8 +/- 0.7, P = 0.008) and CVRI markedly increased (0.28 to 0.35, P = 0.012) after smoking. CONCLUSION: After 4 hours of abstinence from smoking, CFR and CVRI in smokers were similar to those of nonsmokers. However, consecutively smoking two cigarettes acutely reduced CFR and increased CVRI. These findings suggested that smoking could reduce coronary blood flow immediately, even in healthy people.     

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.     

Coronary flow velocity reserve measurement in three major coronary arteries using transthoracic Doppler echocardiography

BACKGROUND: Measurement of the coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of significant coronary artery stenosis or myocardial ischemia. The purpose of this study was to evaluate the value of this method in three major coronary arteries for detecting myocardial ischemia in the clinical setting. METHODS: We studied 89 consecutive patients who were referred to our outpatient clinic because of chest pain. We measured CFVR using TTDE in three major coronary arteries. We defined CFVR<2.0 in at least one vessel as being positive for myocardial ischemia. The accuracy of CFVR measurements for detecting myocardial ischemia was determined in comparison with exercise thallium-201 (Tl-201) single photon emission computed tomography (SPECT) as a reference standard. RESULTS: CFVR in at least one vessel was successfully measured in 87 of 89 patients (98%). The sensitivity and specificity of CFVR<2.0 in at least one coronary vessel, in any of the coronary territories, was 86% and 89%, respectively. In terms of assessing myocardial ischemia in each coronary artery territory, the agreement between CFVR<2.0 and Tl-201 SPECT for the left anterior descending coronary artery, the posterior descending coronary artery, and the left circumflex coronary artery territories was 95%, 81%, and 73%, respectively. CONCLUSION: Noninvasive CFVR measurement by TTDE may be useful for detecting myocardial ischemia, as well as for identifying ischemic territories in the clinical setting.     

Detection of patency of internal mammary artery grafts to the left anterior descending artery by transthoracic Doppler echocardiography

BACKGROUND: To determine whether a coronary artery bypass graft (CABG) is patent, we examined the flow of the left internal mammary artery (LIMA) to the left anterior descending artery (LAD) by transthoracic Doppler echocardiography (TTDE). PATIENTS AND METHODS: Eighty-seven patients with CABG (LIMA to distal LAD) were enrolled in the study. The flows from each subject were analyzed by three criteria: mosaic flow at the anastomosis site, distal anterograde flow (ante flow), and proximal retrograde flow (retro flow). RESULTS: On angiography, 79 grafts were patent and eight were not. TTDE study of 79 patent grafts demonstrated mosaic, ante, and retro flow in 63 (79.7%), 74 (93.7%), and 35 grafts (49.4%), respectively. The averaged diastolic peak velocity of ante flow was 26.3 +/- 11.0 cm/sec, significantly higher than that (4.8 +/- 7.1 cm/sec, P < or = 0.0001) in eight patients without patent grafts. These eight patients had no mosaic or retro flow and only three had ante flow. The accuracies to predict patency were 81.6%, 90.8%, and 49.4% for mosaic, ante, and retro flows, respectively. CONCLUSIONS: The existence of mosaic, retro, or sufficient ante flows strongly indicated the patency of LIMA to the LAD. When symptoms are possible to be derived from the occlusion of CABG to LAD, TTDE is a promising method to examine whether a LIMA to LAD bypass is patent.     

经胸彩色多普勒检测冠心病患者冠状动脉左前降支和右冠状动脉远端血流储备

目的评价经胸彩色多普勒超声心动图(TTDE)检测冠状动脉前降支(LAD)和右冠状动脉后降支(PDA)血流储备和开放程度的可行性。方法65例(男48例,女17例)连续临床诊断或疑似冠心病患者,平均年龄(58±14)岁,左室射血分数(49±8)%,用TTDE冠状动脉显像方式于心尖两腔切面显示LAD和PDA远端的血流,在基础状态和持续静脉注射腺苷(140μg·kg-1·min-1)情况下分别测定其冠状动脉血流储备(CFR),结果与冠状动脉造影对比。结果所有患者基础和充血状态LAD血流均得到显示(其中4例应用造影剂),55例患者PDA得到显示(5例应用造影剂),有2例患者PDA闭塞,因此LAD的检测成功率为100%(65/65),PDA的CFR检测成功率为87%(55/63),所有患者腺苷静脉注射时间均少于4min,CFR检测平均时间为(7.3±1.6)min。以CFR≤2.0和CFR≤1.8分别作为判断冠状动脉狭窄(≥50%)和显著狭窄(≥70%)的标准,准确性相近,诊断LAD和RCA狭窄的灵敏度、特异度和ROC曲线下面积分别为89%/93%,86%/84%,0.89/0.92,诊断显著狭窄的灵敏度、特异度和ROC曲线下面积分别为88%/89%,90%/83%,0.94/0.95。结论经胸多普勒超声心动图检测LAD和PDA成功率和诊断冠状动脉狭窄的准确性均较高,有重要临床价值。     

Improving feasibility of posterior descending coronary artery flow recording by transthoracic Doppler echocardiography.

AIMS: Recording coronary arteries' flow by transthoracic Doppler echocardiography (TTDE) is a new task. Despite several studies concerning the left anterior descending artery (LAD) exist, the same for posterior descending coronary artery (PD) do not. Reported feasibility is not more than 76%. The aim of the study was to try to improve feasibility by using an additional two-dimensional view as a guide. METHODS AND RESULTS: PD flow recording was performed in 35 consecutive unselected patients under the guidance of the usual two-dimensional modified view [a two-chamber view (2-C)], and with a new four-chamber modified view (4-C). A semi-quantitative growing-quality score (from 0 to 3 points) to the trace was given. Contrast enhancement was used if PD was not visualized without it. The overall feasibility was 80%. A good or very good velocity signal (TTDE score > or = 2) was observed in 48% of patients without contrast enhancement. Time for first visualization of PD was short and significantly lower in 2-C than in 4-C (66 +/- 39 vs 90 +/- 70 s, respectively, P<0.05). CONCLUSIONS: TTDE recording of PD flow gained better feasibility being guided by two views. Maximal time for first visualization of PD was less than 3 min.     

Simultaneous transesophageal Doppler assessment of coronary flow reserve in the left anterior descending artery and coronary sinus allows differentiation between proximal and non-proximal left anterior descending artery stenoses.

AIM AND METHODS: The role of simultaneous transesophageal Doppler assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) and coronary sinus (CS) in the diagnostics of hemodynamically significant LAD stenoses of various localization was studied in 16 CAD patients with angiographically proven >50% stenotic atherosclerosis of the LAD (nine--in the proximal third, seven--in the mid and/or distal third) and 23 healthy volunteers (all men). Dipyridamole was used as a stress agent. The diastolic phase of coronary flow in the LAD and the antegrade phase of coronary flow in the CS were analyzed. CFR in the LAD and CS was calculated in two ways: one--as ratio of peak hyperemic flow velocity to the peak baseline blood flow velocity (CFR by Vp); two--as ratio of volume hyperemic blood flow velocity to the volume baseline blood flow velocity (CFR by VBF). The level of the CFR <2 in both ways of calculation was diagnosed as reduced. RESULTS: It was found that in CAD patients with LAD proximal stenosis the values of CFR in the LAD were significantly lower than those in healthy individuals by both Vp (1.87 +/- 0.43 and 3.54 +/- 0.82; P<0.001) and VBF (1.79 +/- 0.77 and 3.85 +/- 1.25; P<0.01). In proximal stenosis CFR in the LAD by Vp was significantly lower than that in non-proximal stenosis (1.87 +/- 0.43 and 3.31 +/- 1.44; P<0.05). Sensitivity and specificity of CFR <2 in the LAD by Vp in the diagnostics of LAD proximal stenosis were 56% and 97%, respectively; and CFR <2 in the LAD by VBF--89% and 93%, respectively. In CAD patients with both proximal and non-proximal LAD stenoses CFR in the CS by Vp was significantly lower than that in healthy volunteers and was 1.74 +/- 0.53, 1.63 +/- 0.30 and 2.56 +/- 0.87; P<0.05, respectively. Sensitivity and specificity of CFR <2 in the CS by Vp in the diagnostics of hemodynamically significant LAD stenoses were 75% and 70%, respectively. The values of CFR in the CS by VBF in CAD patients and healthy volunteers did not differ significantly. CONCLUSIONS: Thus, simultaneous evaluation of CFR in the LAD and CS makes it possible to diagnose hemodynamically significant LAD stenoses and to differentiate between proximal and non-proximal impairments.     

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.     

Evaluation of improved coronary flow velocity reserve using transthoracic Doppler echocardiography after single LDL apheresis

The purpose of this study was to clarify whether coronary flow velocity reserve (CFVR), evaluated by adenosine 5'-triphosphate-induced hyperemia, is improved by single low-density lipoprotein (LDL) apheresis. Lipid lowering therapy is known to improve endothelium-dependent vasodilatation in forearm or coronary resistant vessels. However, few reports have studied the effect of acute LDL reduction on CFVR. Methods: Seven patients with familial hypercholesterolemia and significant coronary stenosis except in the left anterior descending artery (LAD) were enrolled in this study. Coronary flow velocity reserve was estimated before and after LDL apheresis using transthoracic Doppler echocardiography (TTDE), which detects the flow velocity at the distal site of the LAD. Although the averaged diastolic peak velocity (ADPV) during ATP-induced hyperemia was similar before and after LDL apheresis, the ADPV at baseline decreased from 30.69 to 25.56 cm/s, resulting in an increased CFVR from 1.78 to 2.10 (P < 0.001). Plasma bradykinin and 6 keto PGF1alpha increased while fibrinogen and plasma viscosity decreased after apheresis. Single LDL apheresis improves CFVR according to TTDE analysis because of the decreasing ADPV at baseline, which is thought to be induced by epicardial coronary artery dilatation and improved microvessel function. This is the result of various factors, such as changes in plasma LDL cholesterol, bradykinin and PGI2 levels with LDL apheresis.     

Comparison of transesophageal coronary sinus and left anterior descending coronary artery doppler measurements for the assessment of coronary row reserve

Background: Currently used methods for assessment of coronary flow reserve are invasive and require extensive laboratory equipment. Recently, noninvasive assessment of coronary flow reserve by transesophageal Doppler evaluation of coronary sinus (CS) or left anterior descending coronary artery (LAD) flow has been proposed. Direct comparison between these two techniques is lacking. Methods: Doppler recordings of CS and LAD flow velocity were obtained before and after 0.6 mg/kg/5 min dipyridamole in 16 patients with significant stenosis of the LAD (Group A) and in 14 control patients (Group B). Flow recordings and all measurements were performed in a blinded manner. For assessment of coronary flow reserve, Doppler measurements after dipyridamole were divided by the respective baseline values. Results: Doppler studies of the CS and LAD were feasible in 30 of 30 (100%) and 23 of 30 (71%) patients, respectively. Analyzing the maximum flow velocities, coronary flow reserve in Groups A and B was 1.18 ± 0.28 and 1.68 ± 0.53 with CS recordings and 1.78 ± 0.83 and 2.51 ± 0.76 with LAD recordings, respectively. Analyzing the velocity time integrals, coronary flow reserve in Groups A and B was 1.53 ± 0.68 and 2.59 ± 0.74 with CS recordings and 1.77 ± 0.38 and 2.68 ± 0.93 with LAD recordings, respectively. Correlation between LAD and CS recordings was 0.69 (p<0.001), when coronary flow reserve was calculated from the velocity time integral and 0.68 (p<0.001) when the maximum flow velocities were used. Conclusion: Both transesophageal Doppler techniques might be useful for noninvasive assessment of coronary flow reserve.     

Detection of impaired coronary flow reserve in coronary artery disease using transthoracic echocardiographic assessment of coronary sinus blood flow

In order to establish whether coronary flow reserve (CFR) can be measured by transthoracic echocardiography (TTE) with pulse wave Doppler echocardiography, 14 patients with coronary artery disease (CAD) and 12 normal subjects were studied. Coronary sinus blood flow was measured at rest and 2 minutes after intravenous injection of 0.56 mg/kg dipyridamole (DP). CFR was calculated as the DP to rest flow ratio. Patients with CAD were found to have significantly decreased CFR when compared to normal subjects. These findings suggest that TTE may be useful in diagnosing CAD.     

Assessment of coronary flow reserve by transthoracic Doppler echocardiography in left apical ballooning syndrome

We present the time course of transthoracic coronary flow reservein the left anterior descending artery in a patient who suffereda transient left apical ballooning syndrome.     

经胸多普勒超声冠状动脉血流储备检查诊断左前降支显著狭窄

目的比较经胸多普勒超声冠状动脉血流储备（CFR）指标诊断左前降支（LAD）显著狭窄的临床价值。方法连续120例怀疑冠心病的患者于冠状动脉造影（CAG）前一天进行双嘧达莫（0．56mg／kg）负荷试验，测定LAD的CFR指标，包括收缩期最大冠状动脉血流储备（SCFRpeak）、收缩期平均冠状动脉血流储备（SCF Rmean）、收缩期流速时间积分储备（SCFRVTI）、舒张期最大冠状动脉血流储备（DCFRpeak）、舒张期平均冠状动脉血流储备（DCFRmean）和舒张期流速时间积分储备（DCFRVTI）。结果82例获得LAD血流频谱，按照CAG结果分为LAD显著狭窄组（A组，≥70％狭窄，n=16）和LAD非显著狭窄组（B组，〈70％狭窄，n=66）。A组患者各项CFR指标均显著低于B组。ROC曲线法分析显示，DCFRmean〈1．825诊断LAD显著狭窄的敏感性和特异性相对较高。结论经胸多普勒超声评价CFR有助于检出LAD显著狭窄，DCFRmean〈1．825是较好的判别指标。     

Prognostic value of transthoracic coronary flow reserve in medically treated patients with proximal left anterior descending artery stenosis of intermediate severity

Aims: Prognostic value of transthoracic coronary flow reserve (T-CFR)is not established in patients with left anterior descendingartery (LAD) stenosis of intermediate severity. Objective isto determine the prognosis value of T-CFR > 2 in medicallytreated patients with angiographically intermediate [50–70%QCA (quantitative coronary angiography)] proximal LAD stenosis. Methods and results: Among 110 consecutive patients with intermediate LAD stenosiswho underwent prospectively T-CFR in the distal part of theLAD after intravenous administration of adenosine to assessthe functional significance of the stenosis, 80 patients hadT-CFR > 2 and were treated medically without revascularization(Group 1). Among the 30 patients who had T-CFR < 2, an additionaldobutamine stress echocardiography (DSE) was performed: 15 hada negative DSE; were treated medically and served as a comparativegroup (Group 2), and 15 had a positive DSE; underwent LAD revascularization,and were excluded from further analysis. All patients completedfollow-up (16 ± 10 months). During the follow-up period(range 6–45 months), 76 patients (95%) remained free ofdeath or LAD-related event in Group 1, vs. 12 patients (80%)in Group 2. By Kaplan–Meier method, at 30 months the percent estimated survival free from death or target vessel-relatedevents was 92 ± 4% in Group 1 and 44 ± 22% inGroup 2 (P < 0.01). By multivariate analysis, T-CFR remainedthe only independent predictor of death or LAD-related events. Conclusion: In patients with proximal LAD stenosis of intermediate severityand T-CFR > 2, deferral of revascularization is associatedwith low event rate.     

Single administration of cerivastatin, an HMG-CoA reductase inhibitor, improves the coronary flow velocity reserve: a transthoracic Doppler echocardiography study

HMG-CoA reductase inhibitors (statins) have been shown to improve the endothelial function by lowering lipids. Recent studies also suggest a direct impact of statins on the vascular wall. We assessed the rapid effect of cerivastatin on the coronary flow velocity reserve (CFVR) using transthoracic Doppler echocardiography (TTDE). The coronary flow velocity from the distal left anterior descending artery was measured in 16 healthy subjects (all male, age 24–38 years) using a 5-MHz transducer, on the day before, just before, and 3 h after administering 0.3 mg of cerivastatin. Hyperemia was achieved by the intravenous administration of adenosine, and the CFVR was calculated as the radio of the mean diastolic hyperemic coronary flow velocity to the basal flow velocity. The serum lipid profile and high-sensitivity C-reactive protein (hsCRP) were measured. The CFVR following the single administration of cerivastatin increased from 2.93 ± 0.58 to 3.91 ± 0.86, P = 0.003, and was significantly higher than the CFVR measured at the same time on the previous day (3.91 ± 0.86 vs 3.37 ± 0.48, P = 0.009). Neither the serum lipid profile nor hsCRP exhibited a remarkable change after cerivastatin administration. We concluded that a single-dose administration of cerivastatin, an HMG-CoA reductase inhibitor, improves the coronary flow velocity reserve without modifying the serum lipid profile.     

Agreement between coronary flow velocity reserve and stress echocardiography in intermediate-severity coronary stenoses.

Visual and quantitative assessments of percent diameter stenosis on coronary angiography correlate poorly with functional testing, particularly in intermediate-severity (40%-70%) lesions, yet are frequently relied on to make decisions regarding revascularization. Coronary flow velocity reserve (CFVR) and relative CFVR (RCFVR) are promising methods for on-line functional assessment of lesion severity in the catheterization laboratory. We sought to determine the agreement between maximal, mean, and relative CFVR and stress echocardiography in intermediate-severity stenoses. The results of exercise or dobutamine stress echocardiography and CFVR measured by intracoronary Doppler were compared in 28 patients referred for assessment of intermediate-severity stenoses, using 15 patients with either angiographically normal coronary arteries or diameter stenoses > 70% as reference groups. CFVR was measured at least three times in response to a bolus of adenosine in the target vessel distal to the stenosis. RCFVR (target/normal vessel CFVR) was also measured in 27 patients. Maximal, mean (of three measures), and relative CFVR were calculated. CFVR > or = 2.0 and RCFVR > or = 0.75 were accepted as normal. A minority (29%) of patients in the intermediate-severity stenosis group had a positive test by either method. There was good to very good agreement between stress echocardiography and maximal CFVR (84%, kappa = 0.62, P < 0.0001) and RCFVR (81%, kappa = 0.59, P < 0.001) across the entire patient cohort, though in the intermediate subgroup concordance was only fair. Using the mean (of three measures of) CFVR for the same comparison improved the agreement in the intermediate subgroup to good (86%, kappa = 0.58, P = 0.002), and in the entire cohort the agreement was very good (88%, kappa = 0.74, P < 0.0001). There was only fair correlation between measures of CFVR and percent coronary stenosis. CFVR improved from 1.8 +/- 0.8 to 2.7 +/- 0.7 after percutaneous intervention (n = 12, P < 0.0001). These results suggest that there is good agreement between CFVR and stress echocardiography across a wide range of coronary lesion severity. The mean of three CFVR measurements distal to the target vessel stenosis increases diagnostic accuracy. Intracoronary Doppler flow velocity measurements at the time of cardiac catheterization may facilitate improved decision-making by providing the ability to assess the functional significance of coronary stenoses on-line.