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.     

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.     

How Can Coronary Flow Reserve Be Altered by Severe Aortic Stenosis?

The coronary flow reserve, a well-known characteristic of the distensibility of the coronary arteries, can be measured by means of dipyridamole stress transesophageal echocardiography. This study compared the coronary flow reserve in patients with normal coronary arteries with aortic stenosis (Group 1), in patients with normal coronary arteries without aortic stenosis (Group 2), and in patients with significant left anterior descending coronary artery disease (Group 3). PATIENTS AND METHODS: Groups 1 and 2 were comprised of 21 patients each, while Group 3 was comprised of 37 patients. Transesophageal stress echocardiography was carried out according to a standard protocol, with a vasodilator stimulus of dipyridamole in a dose of 0.56 mg/kg over 4 minutes. The coronary flow reserve was calculated as the ratio of posthyperemic to basal peak (CFR) and mean (mean CFR) diastolic flow velocities. RESULTS: The left ventricular mass and left ventricular mass index were significantly higher in Group 1 than in Groups 2 and 3. The coronary flow reserve and the posthyperemic mean diastolic flow velocities were significantly lower, while the resting mean diastolic flow velocities were significantly higher in Groups 1 and 3 than in Group 2. CONCLUSIONS: In patients with aortic stenosis and a normal coronary angiogram, the coronary flow reserve is significantly lower, similarly as in the case of significant left anterior descending coronary artery disease. In severe aortic stenosis with left ventricular hypertrophy, stress transesophageal echocardiography is unable to distinguish between the drop in coronary flow reserve caused by a vascular or a myocardial component, and therefore, not suitable for the selection of patients with significant coronary artery disease, even in cases of left anterior descending coronary artery disease.     

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.     

Transient myocardial dysfunction during pharmacologic vasodilation as an index of reduced coronary reserve: a coronary hemodynamic and echocardiographic study

Regional coronary flow reserve and regional myocardial contractility were evaluated in 29 patients after maximal pharmacologic coronary vasodilation (intravenous dipyridamole, 0.56 mg/kg body weight, administered over 4 minutes). Nineteen patients had a severe (80 to 99%) proximal and isolated stenosis of the left anterior descending coronary artery and 10 patients had normal coronary arteries; all had normal ventricular function under rest conditions. Myocardial contractility was assessed by means of continuous two-dimensional echocardiographic monitoring; coronary reserve was evaluated by coronary sinus thermodilution. After dipyridamole infusion, 9 of the 19 patients with left anterior descending artery stenosis had transient myocardial asynergy involving the septum or apex, or both (Group IA), whereas 10 patients showed no asynergy (Group IB). No impairment of contractility was observed in the 10 patients with normal coronary arteries (Group II). Coronary blood flow was measured under basal conditions and up to 10 minutes after the end of dipyridamole infusion. In patients in Group II, dipyridamole induced an increase in great cardiac vein flow of 167 +/- 68% (mean +/- SD). The 10 patients in Group IB showed a response comparable with that of the control group (Group II) (136 +/- 45% increase in great cardiac vein flow; NS versus Group II), whereas the 9 patients in Group IA had an increase of 46 +/- 30% (p less than 0.01 versus both Group IB and Group II). No significant difference was found in the angiographic severity of the stenosis expressed in terms of minimal cross-sectional area (Group IA = 0.30 +/- 0.13 mm2, Group IB = 0.34 +/- 0.18 mm2; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of coronary flow reserve using myocardial contrast echocardiography in humans.

To evaluate the applicability of myocardial contrast echocardiography for the assessment of coronary blood flow reserve, 21 consecutive patients undergoing coronary angiography were studied. Only patients with a single left anterior descending lesion or normal coronary angiogram were included. Intracoronary injections of sonicated albumin were performed before and after the administration of intracoronary papaverine. Good quality studies at baseline and after the administration of papaverine were obtained in 14 of 21 patients. Ten patients had a significant (greater than 75%) single left anterior descending lesion and four had normal or insignificant lesions (70% or less stenosis) in the left anterior descending coronary artery. Time-intensity curves for the left anterior descending coronary artery region of interest were generated and then the peak contrast intensity (PCI), washout half-time (T1/2) and the area under the curve (AUC) were calculated. The post-papaverine increases in PCI and in the AUC, compared to baseline, were 55 +/- 22% and 102 +/- 14% in the four patients with 70% or less left anterior descending diameter stenosis serving as a control group and 3 +/- 25% and 40 +/- 10%, respectively, in the 10 patients with significant left anterior descending coronary artery disease (mean +/- 1 SD, P less than 0.01). In patients with normal coronary arteriography T1/2 increased after intracoronary injection of papaverine. In patients with severe lesions, either an increase or a decrease in T1/2 was observed. Significant left anterior descending coronary artery stenosis associated with impaired coronary blood flow reserve can be detected by failure of myocardial contrast echocardiographic parameters to increase after injection of papaverine. Mild and transient side effects were noted in three patients.     

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.     

Transesophageal Doppler echocardiography evaluation of coronary blood flow velocity in baseline conditions and during dipyridamole-induced coronary vasodilation

Transesophageal echocardiography allows the evaluation of proximal coronary artery anatomy and coronary blood flow velocity (CBFV). To assess the potential of transesophageal echocardiography in evaluating CBFV and its variations induced by coronary-active drugs, we studied 15 patients by high-quality pulsed wave Doppler recordings of CBFV. In these patients, transesophageal Doppler evaluation of CBFV was performed before, 2 minutes after cessation of dipyridamole infusion (0.56 mg/kg in 4 minutes), and 2 minutes after aminophylline infusion (240 mg injected 4 minutes after cessation of dipyridamole infusion). The following CBFV parameters were evaluated at each of the three steps of the study protocol: maximal and mean diastolic velocities and maximal and mean systolic velocities. Furthermore, the following indexes of coronary flow reserve were evaluated: the ratio between maximal diastolic velocity recorded after and before dipyridamole administration and the ratio between mean diastolic velocity recorded after and before dipyridamole administration. Nine of the 15 patients had a normal left anterior descending coronary artery (group A), whereas the remaining six had significant (less than or equal to 75%) stenosis (group B). In group A patients, all CBFV parameters increased significantly during dipyridamole infusion and returned to near baseline values after aminophylline infusion. In group B patients, on the other hand, none of the CBFV parameters increased after dipyridamole infusion. Dipyridamole/baseline maximal diastolic velocity and mean diastolic velocity ratios were, respectively, 3.22 +/- 0.96 and 3.04 +/- 0.88 in group A and 1.46 +/- 0.45 (p less than 0.01 versus group A) and 1.48 +/- 0.49 (p less than 0.01 versus group A) in group B patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Serial evaluation of coronary flow reserve by transesophageal doppler echocardiography after angioplasty of proximal left anterior descending coronary artery: a 6-month follow-up study

BACKGROUND: Coronary flow reserve can be estimated by transesophageal Doppler echocardiography (TDE). OBJECTIVE: To evaluate the coronary flow reserve by TDE, serially over 6 months' follow-up, after successful percutaneous transluminal coronary angioplasty (PTCA) of proximal left anterior descending coronary artery (LADA). METHODS AND RESULTS: We performed TDE examination of 30 patients (mean age 55 +/- 9 years) 72 h, 3 months, and 6 months after PTCA of LADA. Selective angiography of LADA was repeated 72 h and 6 months after PTCA of LADA. Velocity of flow in LADA was measured before and 2 min after cessation of intravenous infusion of dipyridamole (0.56 mg/kg in 4 min). The dipyridamole: rest mean diastolic velocity ratio was considered as an index of coronary flow reserve (CFR). For 20 of 21 patients with CFR > 2 there was no restenosis, whereas coronary angiography revealed restenosis in eight of nine patients with CFR < 2. The sensitivity was 88.9% and the specificity was 95.2%. For the 21 patients without restenosis mean CFR was 2.1 +/- 0.1 72 h after PTCA, had increased to 3.1 +/- 0.3 (P < 0.0001) 3 months after PTCA, and remained stable thereafter (3.0 +/- 0.9). CONCLUSION: CFR after PTCA of proximal LADA can be evaluated serially by transesophageal Doppler echocardiography. CFR of LADA in patients without restenosis is increased 3 months after PTCA and remains stable thereafter.     

Comparison of transesophageal doppler coronary flow reserve measurements with thallium-201 single-photon emission computed tomography imaging in assessment of left anterior descending artery stenoses

Background and hypothesis: Recent studies demonstrate the feasibility of coronary flow reserve measurements by transesophageal echocardiographic (TEE) Doppler recordings of coronary sinus or left anterior descending (LAD) coronary artery flow velocity for detecting stenoses of the LAD artery. This study compares coronary flow reserve measurements by Doppler TEE with thallium-201 (²⁰¹T1) single-photon emission computed tomography (SPECT) in patients with proximal single-vessel LAD stenosis. Methods: Nineteen patients with various degrees of LAD stenosis (mean area stenosis 71 ± 24%; range 24-96%) were studied. Area stenosis by quantitative coronary angiography was < 75% in 7 patients and > 75% in 12 patients. Transesophageal LAD and coronary sinus Doppler measurements were performed at baseline and after intravenous dipyridamole. Coronary flow reserve was calculated as the ratio of hyperemic to baseline average peak velocities. Predefined coronary flow reserve cut-off values of 1.8 for the coronary sinus method and of 2.0 for the LAD method were used for diagnosis of significant LAD stenosis. Results were compared with qualitative ²⁰¹T1 dipyridamole SPECT. Results: Overall predictive accuracy for diagnosis of > 75% LAD stenosis was 79% for ²⁰¹T1 SPECT, 77% for the transesophageal LAD and 79% for the transesophageal coronary sinus technique. Concordant results between ²⁰¹T1 SPECT and the LAD and coronary sinus Doppler methods were observed in 79% and 71% of patients, respectively. Conclusions: Thallium-201 SPECT and transesophageal Doppler assessment of coronary flow reserve have similar accuracy for diagnosing significant proximal LAD stenosis. Therefore, both transesophageal Doppler techniques might constitute another widely available, noninvasive method for assessment of left coronary artery disease, if disease location is proximal.     

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.     

Reduced coronary flow and resistance reserve in primary scleroderma myocardial disease

The maximum coronary vasodilator capacity after intravenous dipyridamole (0.14 mg X kg-1 X min-1 X 4 minutes) was studied in seven patients with primary scleroderma myocardial disease and compared to that of seven control subjects. Hemodynamic data and left ventricular angiographic data were not different in the two groups. The coronary flow reserve was evaluated by the dipyridamole/basal coronary sinus blood flow ratio (D/B CSBF) and the coronary resistance reserve by the dipyridamole/basal coronary resistance ratio (D/B CR). Coronary reserve was greatly impaired in the group with primary scleroderma myocardial disease: D/B CSBF was lower than in the control group (2.54 +/- 1.37 vs 4.01 +/- 0.56, respectively; p less than 0.05) and D/B CR was higher than in the control group (0.47 +/- 0.25 vs 0.23 +/- 0.04, respectively; p less than 0.05). Such a decreased coronary flow and resistance reserve in patients with primary scleroderma myocardial disease was not explained by an alteration of left ventricular function. It may be an important contributing factor in the pathogenesis of primary scleroderma myocardial disease.     

Physiologic assessment of coronary artery stenosis by coronary flow reserve measurements with transthoracic Doppler echocardiography: comparison with exercise thallium-201 single piston emission computed tomography

OBJECTIVES: We evaluated the value of coronary flow reserve (CFR), as determined by transthoracic Doppler echocardiography (TTDE), for physiologic assessment of coronary artery stenosis severity, and we compared TTDE measurements with those obtained by exercise thallium-201 (Tl-201) single-photon emission computed tomography (SPECT). BACKGROUND: Coronary flow reserve measurements by TTDE have been reported to be useful for assessing angiographic left anterior descending coronary artery (LAD) stenosis. However, discrepancies exist between angiographic and physiologic estimates of coronary lesion severity. METHODS: We studied 36 patients suspected of having coronary artery disease. The flow velocity in the distal LAD was measured by TTDE both at rest and during intravenous infusion of adenosine. Coronary flow reserve was calculated as the ratio of hyperemic to basal peak (peak CFR) and mean (mean CFR) diastolic flow velocities. The CFR measurements by TTDE were compared with the results of Tl-201-SPECT. RESULTS: Complete TTDE data were acquired for 33 of 36 study patients. Of these 33 patients, Tl-201-SPECT confirmed reversible perfusion defects in the LAD territories in 12 patients (group A). Twenty-one patients had normal perfusion in the LAD territories (group B). Peak CFR and mean CFR (mean value +/- SD) were 1.5 +/- 0.6 and 1.5 +/- 0.7 in group A and 2.8 +/- 0.8 and 2.7 +/- 0.7 in group B, respectively. Both peak and mean CFR < or = 2.0 predicted reversible perfusion defects, with a sensitivity and specificity of 92% and 90%, respectively. CONCLUSIONS: Noninvasive measurement of CFR by TTDE provides data equivalent to those obtained by Tl-201-SPECT for physiologic estimation of the severity of LAD stenosis.     

Measurement of coronary flow velocity with Doppler catheter: evaluation of coronary flow reserve in successful angioplasty

To assess the therapeutic effect of percutaneous transluminal coronary angioplasty (PTCA) on coronary flow reserve, coronary flow velocity (CFV) was measured with a Doppler catheter before and immediately after PTCA in 11 patients, who underwent elective PTCA for critical stenosis in proximal or mid portion of the left anterior descending artery (LAD). A Doppler catheter was positioned at the proximal portion of the LAD and the CFV was measured at rest and after intracoronary injection of 6 ml of contrast material (Iopamidol), 6 ml of saline or 3 mg of Isosorbide Dinitrate (ISDN). Peak to resting velocity ratio (PRVR) was calculated as an estimate of coronary flow reserve. Percent diameter stenosis (%S) was measured from cineangiogram. A translesional pressure gradient was obtained with an angioplasty catheter. These parameters measured in PTCA candidates were compared with those in 11 patients whose LAD had no critical stenosis. After PTCA, %S was decreased (94.2 +/- 1.4 vs 34.1 +/- 5.1%; mean +/- SEM). Pressure gradient was also decreased (59.5 +/- 4.9 vs. 25.1 +/- 3.3 mmHg). There was no difference between mean CFV at rest in patients before PTCA and that in patients without stenosis (4.52 +/- 0.63 vs. 5.46 +/- 0.61 cm/sec). By successful PTCA, CFV at rest was increased (7.39 +/- 1.32, p less than 0.05 vs. before PTCA). PRVRs in patients before PTCA were smaller than those in patients without stenosis (1.5 +/- 0.1, 1.4 +/- 0.1, 1.6 +/- 0.2 vs. 2.8 +/- 0.1, 2.5 +/- 0.2, 2.8 +/- 0.2, p less than 0.01; by contrast material, saline, ISDN, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

急性高血糖犬心表冠状动脉和心肌微血管的储备功能

应用血流仪和心肌对比超声心动图测量犬基础状态和高血糖状态冠状动脉前降支和心肌微血管的血流量,应用双嘧达莫后,前降支血流量和血流储备无明显变化,而心肌微血管的密度、血流量和血流储备明显下降。     

Diminished coronary flow velocity reserve and aortic distensibility in elderly patients with chest pain and negative coronary angiograms

BACKGROUND AND AIMS: Aging is a dominant process that alters vascular stiffness, endothelial function and coronary flow regulation. The objective of our work was to assess simultaneously the elastic properties of the descending aorta and coronary flow velocity reserve (CFR) during the same transesophageal echocardiography (TEE) in elderly patients. METHODS: The following patients with normal epicardial coronary arteries were compared: 30 subjects under 55 years of age (group 1) and 17 patients over 55 years (group 2). A complete TEE examination was carried out in all patients, and the following aortic elastic properties were calculated from aortic diameter and blood pressure data: aortic elastic modulus [E(p)] and Young's circumferential static elastic modulus [E(s)]. Doppler evaluation of left anterior descending coronary flow velocity was performed in resting conditions and after administration of 0.56 mg/Kg dipyridamole over 4 min. Peak coronary flow velocities were measured at the 6th minute at maximum vasodilation. CFR was estimated as the ratio of hyperemic to basal peak diastolic coronary flow velocities. RESULTS: Peak hyperemic diastolic coronary flow velocities were significantly decreased (139.1+/-35.6 cm/s vs 105.7+/-39.7 cm/s, p<0.01) in patients >55 years. CFR was decreased (2.67+/-1.05 vs 2.13+/-0.56, p<0.05), whereas E(p) (in 103 mmHg, 0.59+/-0.49 vs 0.94+/-0.65, p<0.05) and E(s) (in 103 mmHg, 5.70+/-4.30 vs 8.47+/-5.14, p<0.05) were increased in patients >55 years. A correlation was found between CFR and E(p) (r=-0.20, p<0.05). CONCLUSIONS: CFR and aortic distensibility are altered in elderly patients. There is a relationship between these functional parameters.     

Usefulness of dipyridamole transesophageal echocardiography in the evaluation of myocardial ischemia and coronary artery flow

High-dose dipyridamole transesophageal stress echocardiography has recently been proposed as a useful and safe method to assess myocardial ischemia in patients with a poor transthoracic acoustic window. It has also been shown that transophageal echocardiography (TEE) allows the study of coronary blood flow reserve (CBFR) in the left anterior descending artery (LAD).The aim of our study was to assess whether the morphologic information and pathophysiologic data on CBFR and myocardial ischemia can be collected by a single stress TEE without comprimising its feasibility, safety and accuracy. We studied, 29 patients with known or suspected CAD (previous myocardial infarction or angina) (Group A), and as a control group, we studied 11 patients with mitral disease or mitral prostheses (Group B).All patients underwent the coronary angiography. None of Group B patients showed significant coronary artery stenosis (>70%). In baseline conditions left ventricular wall motion and LAD coronary blood flow velocity (CBFV) were also evaluated. The following CBFV parameters were measured: maximal diastolic velocity (MaxDV), mean diastolic velocity (MnDV), maximal systolic velocity (MaxSV), mean systolic velocity (MnSV). The ratios of dipyridamole to rest maximal and to mean to diastolic velocities (MaxDV-Dip/Max DV-rest; MnDv-Dip/MnDV-rest) were measured as indexes of CBFR.No side effects were observed and the test could be completed in all patients (feasibility 100%). Wall motion analysis was adequate in all patients (feasibility 100%). Comparison between wall motion analysis was obtained and angiographic findings showed that the overall sensitivity and specificity of TEE were 84% and 93% respectively. Sensitivity for one, two and three vessel disease was 60%, 70% and 100%, respectively. LAD CBFV was adequately recorded in 85% of patients. CBFR parameters showed a significant difference between the two groups (Max DV-Dip/Max DV-rest; 1.67±0.7 vs. 2.73±0.6,P<0.001); comparison between Group B patients and those of Group A with angiographically documented LAD stenosis showed a statistically significant difference in CBFR parameters (MaxDV-Dip/MnDV-rest, 2.73±0.6 vs. 1.65±0.7,P<0.001, MnDV-Dip/MnDV-rest, 2.56±0.5 vs. 1.69±0.6 P<0.001). We conclude that transesophageal stress echocardiography is a useful method to study CAD and that it is possible to assess both morphologic and pathophysiologic information during a single examination.     

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

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

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.