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Cardiovascular Research 1997 36(1):21-27; doi:10.1016/S0008-6363(97)00166-1
© 1997 by European Society of Cardiology
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Copyright © 1997, European Society of Cardiology

Transesophageal versus intracoronary Doppler measurements for calculation of coronary flow reserve1

Manfred Zehetgruber*, Gerold Porenta, Gerald Mundigler, Deddo Mörtl, Thomas Binder, Günter Christ, Peter Probst, Helmut Baumgartner, Gerald Maurer and Peter Siostrzonek

Department of Cardiology, University of Vienna, Währinger Gürtel 18-20 Vienna A-1090, Austria

* Corresponding author. Tel.: +43-140-400-4614; fax: +43-140-81148.

Received 25 February 1997; accepted 29 May 1997


   Abstract
Top
 Abstract
1 Introduction
 2 Methods
 3 Results
 4 Discussion
 References
 
Objective: The present study was performed to compare coronary flow reserve by transesophageal Doppler echocardiography and intracoronary Doppler flow wire measurements in patients with LAD disease. Methods: 17 patients with various degree of LAD stenosis were studied. Intracoronary LAD Doppler measurements were performed at baseline and after intracoronary injection of 18 µg adenosine. Transesophageal coronary sinus and LAD Doppler measurements were performed at baseline and after intravenous dipyridamole (0.6 mg/kg/5 min). Coronary flow reserve was calculated as the ratio of hyperemic to baseline average peak velocities. Results: Coronary flow reserve was 2.44±0.62 and 2.19±0.76 for proximal and distal intracoronary measurements and was 2.25±0.64 and 1.74±0.63 for transesophageal LAD- and coronary sinus measurements. Proximal intracoronary flow reserve significantly correlated with transesophageal coronary sinus (r = 0.73, p≤0.001) and LAD (r = 0.70, p≤0.005) measurements, whereas distal intracoronary flow reserve only correlated with transesophageal coronary sinus flow reserve (r = 0.56, p≤0.02). Receiver operating characteristic curve analysis demonstrated similar diagnostic accuracy of all applied techniques for detection of a significant LAD stenosis. Conclusions: Coronary flow reserve by both transesophageal techniques correlated with intracoronary Doppler flow wire measurements, however considerable discrepancies may occur in the individual patient.

KEYWORDS Coronary flow reserve; Transesophageal echocardiography; Intracoronary Doppler flow wire; Human; Coronary artery disease


   1 Introduction
Top
 Abstract
 1 Introduction
2 Methods
 3 Results
 4 Discussion
 References
 
The vasodilator capacity of the coronary circulation provides important diagnostic information in a variety of cardiac diseases [1–5]. Accordingly, coronary flow reserve measurements have been employed to assess the physiologic significance of coronary stenoses and to evaluate microcirculatory function in disorders such as syndrome X and left ventricular hypertrophy. Coronary flow reserve measurements are most commonly performed by invasive methods or by positron emission tomography, both techniques being limited in their large-scale applicability [6, 7]. Recent reports suggest the use of non-invasive measurement of coronary flow reserve by transesophageal Doppler echocardiography. Several groups have demonstrated the feasibility of this method by either evaluating blood flow velocity of the proximal left anterior descending coronary (LAD) artery [8–12]or of the coronary sinus [13, 14]before and after vasodilator administration. However, invasive validation of transesophageal Doppler echocardiography by intracoronary measurements has not been performed.

Thus, the present study sought to compare coronary flow reserve as obtained by transesophageal Doppler echocardiography with intracoronary Doppler flow wire measurements.


   2 Methods
Top
 Abstract
 1 Introduction
 2 Methods
3 Results
 4 Discussion
 References
 
2.1 Patients
17 patients with single vessel disease of the proximal LAD without previous Q-wave myocardial infarction were prospectively included in this study. Patients with angiographically visible collateral vessels, wall motion abnormalities at rest, uncontrolled hypertension, elevated right heart pressures, bradycardia and tachycardia were excluded from the study. The mean age of these patients (12 men and 5 women) was 59±2 years. 11 patients had stable angina pectoris, 6 patients were referred for unstable angina pectoris. No patient had angina or ischemic ECG changes at rest.

The investigation conformed with the principles outlined in the Declaration of Helsinki and the study protocol was approved by the local human subjects committee. Written informed consent was obtained from all patients. All vasoactive medication with the exception of short-acting nitrates was discontinued on the study day. Intracoronary measurements and transesophageal studies were performed within 24 h. The echocardiographer was unaware of the results of the Doppler flow wire measurements.

2.2 Coronary angiography
Selective coronary angiography was performed with a 8F Judkins guiding catheter from the femoral artery. Two to three orthogonal projections of the target lesion were obtained using a biplane angiography system (HICOR, Siemens Inc.). Quantitative coronary angiography (QCA) was performed from 35 mm cine film using a commercially available second generation QCA system (CMS, Cardiovascular Measurement System; Medis). Two to three enddiastolic image frames were analysed to obtain percent luminal diameter reduction of the stenosis and the highest stenosis grade was included for further analysis.

2.3 Intracoronary velocity measurements (IC-LAD)
A 0.014 inch, 14 MHz Doppler guide wire (FloWire, Cardiometrics) was advanced into the proximal part of the LAD. Doppler velocity profiles were displayed and an automated tracking algorithm was used to detect the maximal instantaneous flow velocity and to compute average peak velocity over two heart cycles as an index of coronary flow. Once a stable Doppler signal was obtained baseline flow velocity was recorded 1–2 cm proximal to the stenosis. After intracoronary administration of 18 µg adenosine [15, 16]hyperemic flow response was recorded for 90 s. The wire was then advanced to a position ≥2 cm distal to the stenosis and measurements were repeated at baseline and after adenosine. Doppler measurements were recorded twice at each location and the average of two measurements was used for further analysis. Coronary flow reserve was calculated as the ratio of the respective hyperemic to baseline average peak velocity.

2.4 Transesophageal velocity measurements
The study was performed with a VINGMED 800 system (Sonotron) using a multiplane 5 MHz transesophageal probe. Transesophageal echocardiography was performed without sedation using topical anesthesia to the oropharynx. Continuous ECG-recording was obtained and arterial blood pressure was measured noninvasively at baseline and after dipyridamole administration.

2.5 Recording of coronary sinus flow velocity (TEE-CS)
A modified four chamber view with dorsal angulation of the transducer was used to visualize the ostium of the coronary sinus. The position of the probe was optimized until the coronary sinus with its ostium into the right atrium could be visualized throughout the cardiac cycle. Coronary sinus flow velocity recordings were performed with the Doppler sample volume placed in the coronary sinus within a distance of no more than 10 mm from its ostium. In all patients, the angle between the Doppler beam and the long axis of the coronary sinus was less than 30°. Flow signals were recorded during exspiration and were repeated until constant flow signals of adequate quality were obtained.

2.6 Recording of LAD flow velocity (TEE-LAD)
The proximal LAD was visualized by positioning the transducer in a short axis plane slightly superior to the aortic valve. In most patients anterior and lateral angulation of the transducer was necessary for optimal imaging. Flow velocity was recorded by placement of the Doppler sample volume in the proximal LAD. As with coronary sinus recordings attempts were made to minimize the angle between the long axis of the vessel and the ultrasound beam.

After coronary sinus and LAD recordings were obtained at baseline, dipyridamole was administered intravenously at a constant infusion rate of 0.6 mg/kg over a 5 min period. In patients with an inadequate increase of heart rate of less than 10% an additional dipyridamole infusion of 0.28 mg/kg was infused for 2 min. Two minutes after cessation of dipyridamole infusion, coronary sinus and LAD velocity recordings were repeated. In case of anginal pain during dipyridamole infusion, aminophylline (0.12–0.24 g) was administered intravenously. Flow velocity recordings of the LAD and coronary sinus were performed in random order to avoid method-related errors due to different time intervals between dipyridamole administration and the respective flow velocity recordings. Videotape recordings of three to five cardiac cycles with optimum quality before and after dipyridamole were analyzed [8, 10, 13]. For both coronary sinus and LAD recordings, coronary flow reserve was calculated as the ratio of hyperemic to baseline average peak velocity (hand-tracing).

2.7 Statistical analysis
Data are expressed as mean±SD. Intra- and interobserver variability of transesophageal flow reserve measurements was assessed in 10 randomly assigned patients from video-tape recordings. Intraobserver variability was determined by having one observer reevaluate coronary flow reserve at least one month apart and interobserver variability was determined by having two independent observers blindly evaluate flow reserve. For intra- and interobserver variability differences between separate measurements were calculated and the mean difference as well as the standard deviation of the differences were expressed as percentage of the mean coronary flow reserve. An analysis of variance for repeated measures and the Scheffe's F test were performed to compare data obtained by various methods and to compare data before and after vasodilator application. Results of different methods for coronary flow reserve calculation were compared by linear regression analysis as well as by agreement analysis as proposed by Bland and Altman [17]. Sensitivity, specificity and overall predictive value for diagnosing significant coronary lesions (stenosis-diameter ≥50%) [18]were evaluated for various methods of flow reserve calculation. Based on the calculated sensitivities and specificities for various threshold values receiver operating characteristic curves were developed. Additionally, on the basis of previous studies threshold values of 2.0 for measurements in the LAD [19]and of 1.8 [13, 14]for measurements in the coronary sinus were chosen to differentiate normal and abnormal vasodilator capacity. Statistical significance was considered at a p value of <0.05.


   3 Results
Top
 Abstract
 1 Introduction
 2 Methods
 3 Results
4 Discussion
 References
 
3.1 Feasibility and reproducibility
Adequate transesophageal Doppler recordings were obtainable by the coronary sinus method in all patients and by the LAD method in 15 of 17 patients. Acceptable flow velocity signals could not be obtained by intracoronary Doppler in one patient proximal and in two patients distal of the stenosis. Intraobserver variability was 2.1% (SD=7.9%) for the transesophageal coronary sinus and 0.1% (SD=11.2%) for the transesophageal LAD flow reserve. The respective interobserver variabilities were 6.1% (SD=16.9%) and 1.2% (SD=7.3%) for coronary sinus and LAD measurements.

3.2 Hemodynamic data
Hemodynamic data at rest and after vasodilator application are shown in Table 1. At rest blood pressure and heart rate were similar for both methods (p = n.s.), resulting in comparable rate-pressure products (p = n.s.). Heart rate remained unchanged after intracoronary adenosine but increased significantly after intravenous dipyridamole administration. Chest pain was present in one patient after dipyridamole but administration of aminophylline was not required.


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  		Table 1 Hemodynamic findings

 
3.3 Coronary flow reserve
An example of intracoronary and transesophageal Doppler flow velocity recordings in a patients with severe LAD stenosis is presented in Fig. 1. For the total group of patients coronary reserve assessed by the flow wire was 2.44±0.62 for proximal and 2.19±0.76 for distal LAD measurements (p = n.s.), and was 2.25±0.64 for transesophageal LAD and 1.74±0.63 for transesophageal coronary sinus measurements. Compared to the results of all other techniques, flow reserve obtained by coronary sinus flow velocities was significantly lower (p≤0.01).


Figure 1
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  		Fig. 1 (A) Left coronary angiogram demonstrating a 59% diameter stenosis in the proximal LAD. (B) Intracoronary flow velocity recording proximal to the stenosis at baseline and after adenosine resulting in a coronary flow reserve of 1.5. (C) Intracoronary flow velocity recording distal to the stenosis at baseline and after adenosine resulting in a coronary flow reserve of 1.4. (D) Transesophageal Doppler flow velocity recording in the proximal LAD at baseline and after dipyridamole resulting in a coronary flow reserve of 1.9. (E) Transesophageal Doppler flow velocity recording in the coronary sinus at baseline and after dipyridamole resulting in a coronary flow reserve of 1.4.

 
Results of linear regression and agreement analysis between the different methods are presented in Fig. 2. There was a significant correlation between proximal and distal intracoronary flow reserve measurements. A similar degree of correlation was found between proximal intracoronary flow reserve measurements and both transesophageal methods, whereas distal intracoronary flow reserve measurements only correlated with transesophageal coronary sinus flow reserve.


Figure 2
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  		Fig. 2 Left panels: Linear regression analysis between transesophageal LAD (TEE-LAD) (A): coronary sinus (TEE-CS) (B) and proximal (IC-prox) and distal (IC-dist) intracoronary flow reserve (CFR). Right panels: Analysis of an agreement plotting the difference between the respective methods against the mean of the two measurements.

 
3.4 Coronary flow reserve and stenosis severity
Mean diameter stenosis as assessed by quantitative angiography was 47±17% (range: 11–64%). 5 patients had diameter stenosis of <50% and 12 patients of ≥50%. Receiver operating characteristic curves revealed similar diagnostic accuracy for detection of significant LAD stenosis for all applied methods (Fig. 3). Sensitivity, specificity and overall predictive value of the intracoronary flow wire technique and both transesophageal methods for prediction of significant stenosis are shown in Table 2.


Figure 3
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  		Fig. 3 Receiver operating characteristic curves for diagnosis of ≥50% diameter stenosis assessed by proximal (IC-prox) and distal (IC-dist) intracoronary and transesophageal LAD (TEE-LAD) and coronary sinus (TEE-CS) coronary flow reserve. Areas under the curve (A) were not significantly different between the methods applied.

 

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  		Table 2 Accuracy for diagnosis of >50% diameter LAD stenosis using a cut-off coronary flow reserve of 2.0 for intracoronary and transesophageal LAD and 1.8 for transesophageal coronary sinus method

 

   4 Discussion
Top
 Abstract
 1 Introduction
 2 Methods
 3 Results
 4 Discussion
References
 
This study compares assessment of coronary flow reserve by transesophageal Doppler echocardiography with intracoronary Doppler flow wire measurements. It is demonstrated that coronary flow reserve determined by both transesophageal Doppler techniques significantly correlates with intracoronary flow reserve, however considerable discrepancies may occur in the individual patient.

The value of coronary flow reserve as a marker of the functional significance of a coronary stenosis has been previously reported. Several diagnostic techniques have already been validated for determination of coronary flow reserve [7, 20, 21]but their large-scale applicability is limited by the requirement of cardiac catherization or of quantitative PET imaging. Recently, transesophageal flow reserve obtained by assessment of coronary flow reserve was reported [8–14]. However, this new approach has not yet been compared to more established methods such as intracoronary Doppler flow wire measurements.

4.1 Comparison of transesophageal LAD with intracoronary Doppler flow wire measurements
After its introduction by Iliceto et al. [8]. assessment of coronary flow reserve by transesophageal Doppler recordings in the proximal LAD has been applied in several clinical studies [8–12]. In these studies the method allowed seperation of normal subjects from patients with significant LAD stenosis.

The present study demonstrated a significant correlation between flow reserve as assessed by the transesophageal LAD method and intracoronary flow wire measurements proximal to the stenosis. However, no correlation between transesophageal LAD and poststenotic intracoronary measurements could be observed. These discrepancies might be explained by various method-inherent limitations. Transesophageal Doppler recordings are usually limited to a small sampling site in the very proximal segment of the LAD. Therefore, side branching between the actual site of flow recordings and the stenosis might lead to overestimation of coronary flow reserve. Conversly, in patients with very proximal LAD stenoses transesophageal recordings are performed in the proximity of the stenosis, so that turbulent stenotic flow might impact on Doppler recordings. However, discordant coronary flow reserve values due to side branching may also occur with prestenotic intracoronary Doppler measurements and therefore, poststenotic measurements are generally considered superior to prestenotic recordings [22]. However, even intracoronary poststenotic measurements may be influenced by collateral flow and the inability to obtain stable and reproducibile flow signals [23]. Nevertheless, the absence of correlation between poststenotic coronary flow reserve by intracoronary flow wire and prestenotic transesophageal measurements has to be considered a substantial limitation in the assessment of coronary stenoses by transesophageal echocardiography.

Despite significant correlations by prestenotic intracoronary and transesophageal measurements, discordant results may be obtained by the various techniques in the single patient (Fig. 2). According to the results obtained by agreement analysis, a coronary flow reserve of 2.5 by prestenotic intracoronary Doppler measurements could range anywhere between 1.6 and 3.4 by transesophageal LAD Doppler measurements. This is in line with a previous study, comparing coronary flow reserve by transesophageal Doppler measurements in the LAD and positron emission tomography with oxygen 15 water in healthy volunteers [24]. Similarily, a good linear correlation was observed between these two techniques although results also demonstrated some discordance in the individual patient. Nevertheless, it must be noted that agreement analysis has also shown considerable differences between other, more established methods which are routinely applied in clinical practice [25].

4.2 Comparison of transesophageal coronary sinus with intracoronary Doppler guide wire measurements
Recent studies demonstrated the feasibility of transesophageal coronary sinus flow velocity recordings for the assessment of coronary flow reserve. With this method flow reserve was found to be lower in patients with dilated cardiomyopathy and syndrome X as compared to normal subjects [13, 14]. Although the coronary sinus technique may be considered particularily sensitive in patients with global reduction of coronary flow reserve, it has previously been found to be also reduced in the majority of patients with significant LAD disease [14]. Accordingly, the present study showed a significant correlation between coronary flow reserve as assessed by the transesophageal coronary sinus- and the intracoronary Doppler flow wire technique. In contrast to the transesophageal LAD method coronary sinus measurements also significantly correlated with poststenotic intracoronary flow reserve. This may be explained by the various aforementioned limitations of transesophageal LAD measurements, but might also indicate a closer representation of poststenotic flow by the coronary sinus technique.

Coronary flow reserve values were substantially lower by the transesophageal coronary sinus method as compared to all other techniques. Although the reason for this must remain unclear, it has to be noted that lower coronary flow reserve values were also reported for the coronary sinus thermodilution method, when compared to the results of intracoronary Doppler measurements [26].

4.3 Diagnostic accuracy of coronary flow reserve measurements
As shown by similar areas under the respective receiver operating characteristic curves, diagnostic accuracy for detection of a significant LAD stenosis was comparable between both transesophageal and pre- as well as poststenotic intracoronary Doppler flow wire measurements. Using predefined cut off values for diagnosis of severe LAD stenosis, concordant classification by both transesophageal methods was obtained in all but one patient. Discordant results were noticed in a single patient with severe LAD stenosis and a large prestenotic side branch. In this patient coronary flow reserve was 2.38 by transesophageal LAD and 1.22 by coronary sinus Doppler measurements. Accordingly, intracoronary prestenotic flow reserve was higher than poststenotic flow reserve (2.2 versus 1.2, respectively), illustrating the confounding influence of side branching on the assessment of prestenotic coronary flow reserve.

4.4 Study limitations
Transesophageal and intracoronary Doppler studies were not performed simultaneously for logistical reasons. Moreover, different vasodilators were used for each technique. Dipyridamole is commonly used for non-invasive assessment of coronary flow reserve, but due to its prolonged duration of action has only limited applicability in invasive studies. In contrast, adenosine is preferred for intracoronary administration because it enables repeated consecutive flow reserve measurements within a short period of time [27]. However, the dosages used in the present study were reported to produce comparable coronary hyperemia in the majority of patients [28, 29].

Heart rate was similar for both methods at baseline but increased significantly only after dipyridamole administration. However, it is unlikely that this might have influenced our results, since hyperemic blood flow had been previously shown to be unrelated to the achieved rate-pressure product [30–32]. In addition, similar mean coronary flow reserve values were observed with transesophageal LAD and intracoronary Doppler measurements, suggesting comparable hyperemia with both pharmacological stimuli.

The present results were obtained in a highly selected patient group. All patients had single vessel disease with proximal stenosis of the LAD. It remains to be shown whether transesophageal Doppler techniques will also enable detection of more distal LAD stenoses. Furthermore, the transesophageal techniques cannot be applied for functional assessment of stenoses of the right coronary artery and feasibility of the coronary sinus technique in evaluating stenoses of the left circumflex coronary artery is unknown.

QCA was used as reference method for assessment of diagnostic accuracy of various techniques for coronary flow reserve measurements. Although the angiographic aspect of a stenosis is known to correlate poorly with its physiologic significance, quantitative angiography correlated closely with coronary flow reserve in patients with discrete single vessel disease [33].

4.5 Conclusion
Although transesophageal and intracoronary measurements of coronary flow reserve correlated significantly in a group of patients with LAD disease, considerable discrepancies between these methods may occur in the individual patient.

Time for primary review 44 days.


   Notes
 
1 This work was presented in part at the 68th Scientific Sessions of the American Heart Association in Anaheim, November 1995. Back


   References
Top
 Abstract
 1 Introduction
 2 Methods
 3 Results
 4 Discussion
 References
 

  1. Winniford MD, Rossen JD, Marcus ML. Clinical importance of coronary flow reserve measurements. Mod Concepts Cardiovasc Dis 1989; 58:31–35.
  2. Strauer B. The significance of coronary reserve in clinical heart disease. J Am Coll Cardiol 1990; 15:775–783.
  3. Marcus ML, Wright CB, Doty DB, et al. Measurements of coronary velocity and reactive hyperemia in the coronary circulation in humans. Circ Res 1981; 49:877–888.
  4. Uren NG, Melin JA, Bruyne B, et al. Relation between myocardial blood flow and the severity of coronary artery stenosis. N Engl J Med 1994; 330:1782–1788.
  5. Carli MD, Czernin J, Hoh CK, et al. Relation among stenosis severity, myocardial blood flow, and flow reserve in patients with coronary artery disease. Circulation 1995; 91:1944–1951.
  6. White CW, Wilson RF, Marcus ML. Methods of measuring myocardial blood flow in humans. Prog Cardiovasc Dis 1988; 31:79–94.
  7. Doucette JW, Corl PD, Payne HM, et al. Validation of a Doppler guide wire for intravascular measurement of coronary artery flow velocity. Circulation 1992; 85:1899–1911.
  8. Iliceto S, Marangelli V, Memmola C, Rizzon P. Transesophageal Doppler echocardiography evaluation of coronary blood flow velocity in baseline conditions and during dipyridamole-induced coronary vasodilation. Circulation 1991; 83:61–69.
  9. Redberg RF, Sobol Y, Chou TM, et al. Adenosine-induced coronary vasodilation during transesophageal Doppler echocardiography. Rapid and safe measurement of coronary flow reserve ratio can predict significant left anterior descending coronary stenosis. Circulation 1995; 92:190–196.
  10. Stoddard MF, Prince CR, Morris GT. Coronary flow reserve assessment by dobutamine transesophageal Doppler echocardiography. J Am Coll Cardiol 1995; 25:325–332.
  11. Iliceto S, Caiati C, Aragona P. Improved Doppler signal intensity in coronary arteries after intravenous peripheral injection of a lung-crossing contrast agent (SHU 508A). J Am Coll Cardiol 1994; 23:184–190.
  12. Caiati C, Aragona P, Iliceto S, Rizzon P. Improved Doppler detection of proximal left anterior descending coronary artery stenosis after intravenous injection of a lung-crossing contrast agent: a transesophagel Doppler echocardiographic study. J Am Coll Cardiol 1996; 27:1413–1421.
  13. Siostrzonek P, Kranz A, Heinz G. Non-invasive estimation of coronary flow reserve by transesophageal dopplersonographic measurement of coronary sinus flow. Am J Cardiol 1993; 72:1334–1337.
  14. Zehetgruber M, Mundigler G, Christ G. Estimation of coronary flow reserve by transesophageal coronary sinus Doppler measurements in patients with syndrome X and in patients with significant left coronary artery disease. J Am Coll Cardiol 1995; 25:1039–1045.
  15. Wilson RF, Wyche K, Christensen BV, Zimmer S, Laxson DD. Effect of adenosine on human coronary arterial circulation. Circulation 1990; 82:1595–1606.
  16. Kern MJ, Deligonul U, Tatineni S. Intravenous adenosine continous infusion and low dose bolus administration for determination of coronary vasodilator reserve in patients with and without coronary artery disease. J Am Coll Cardiol 1991; 18:718–729.
  17. Bland JM, Altman DG. Statistcal methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1:307–310.
  18. Gould KL, Lipscomb K, Hamilton GW. Physiologic basis for assessing critical coronary stenosis: instantaneous flow response and regional distribution during coronary hyperemia as measures of coronary flow reserve. Am J Cardiol 1974; 33:87–94.
  19. Joye JD, Schulman DS, Lasorda D. Intracoronary Doppler guide wire versus stress single-photon emission computed tomographic thallium-201 imaging in assessment of intermediate coronary stenoses. J Am Coll Cardiol 1994; 24:940–947.
  20. Bergmann SR, Fox KA, Rand AL, et al. Quantification of regional myocardial blood flow in vivo with oxygen-15 and positron emission tomography. Circulation 1984; 70:724–733.
  21. Ganz W, Tamura K, Marcus HS, et al. Measurement of coronary sinus blood flow velocity and vasodilator reserve in man. Circulation 1971; 44:181–195.
  22. Segal J. Applications of coronary flow velocity during angioplasty and other coronary interventional procedures. Am J Cardiol 1993; 71:17D–25D.
  23. Porenta G, Schima H, Steffen W, Probst P, Maurer G, Baumgartner H. Limited accuracy of Doppler guide wire measured velocities to estimate coronary flow an in vitro study. Circulation 1994; 90:I-276.
  24. Radvan J, Marwick TH, Williams MJ, Camici PG. Evaluation of the extent and timing of the coronary hyperemic response to dipyridamole: a study with transesophageal echocardiography and positron emission tomography with oxygen 15 water. J Am Soc Echocardiogr 1995; 8:864–873.
  25. Naik MM, Diamond GA, Pai T, Soffer A, Siegel RJ. Correspondence of left ventricular ejection fraction determinations from two-dimensional echocardiography, radionuclide angiography and contrast cineangiography. J Am Coll Cardiol 1995; 25:937–942.
  26. Rossen LD, Oskarsson H, Stenberg RG, Braun P, Talman CL, Winniford MD. Simultaneous measurement of coronary flow reserve by left anterior descending coronary artery Doppler and great cardiac vein thermodilution methods. J Am Coll Cardiol 1992; 20:402–407.
  27. Wilson RF. Assessment of the human coronary circulation using a Doppler catheter. Am J Cardiol 1991; 67:44D–56D.
  28. Wilson RJ, White CW. Intracoronary papaverine: an ideal coronary vasodilator for studies of the coronary circulation in conscious humans. Circulation 1986; 73:444–451.
  29. Chan SY, Brunken RC, Czernin PG, et al. Comparison of maximal myocardial blood flow during adenosine infusion with that of intravenous dipyridamole. J Am Coll Cardiol 1992; 20:979–985.
  30. McGinn AL, White CW, Wilson RF. Interstudy variability of coronary flow reserve. Influence of heart rate, arterial pressure, and ventricular preload. Circulation 1990; 81:1319–1330.
  31. Rossen JD, Winniford MD. Effect of increases in heart rate and arterial pressure on coronary flow reserve in humans. J Am Coll Cardiol 1993; 21:343–348.
  32. Czernin J, Müller P, Chan S, et al. Influence of age and hemodynamics on myocardial blood flow and flow reserve. Circulation 1993; 88:62–69.
  33. Wilson RF, Marcus ML, White CW. Prediction of physiologic significance of coronary arterial lesions by quantitative lesion geometry in patients with limited coronary artery disease. Circulation 1987; 75:723–732.

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