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A 43-year-old woman with recurrent atypical angina underwent invasive coronary angiography including intracoronary Doppler blood flow assessment and coronary spasm provocation testing. While obstructive epicardial disease could be ruled-out angiographically, the patient experienced reproduction of her angina symptoms after intracoronary administration of acetylcholine (100 µg) during spasm provocation testing. Simultaneously, the ECG showed new-onset ST-segment depression in the absence of epicardial spasm. In addition, coronary flow velocity was significantly reduced after acetylcholine compared to the baseline condition. Following intracoronary administration of nitroglycerine (200 µg), the patient’s symptoms as well as the ECG changes and coronary flow reduction were reversed. Considering the ongoing challenges in appropriate evaluation of the pathophysiological mechanisms of coronary microvascular dysfunction, simultaneous intracoronary Doppler flow measurement during spasm testing – as shown in this case – may provide objective evidence for microvascular spasm in addition to the standardized diagnostic criteria, especially if they are ambiguous.

The measurement of coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) with invasive intracoronary Doppler flow wire technique (ICD) was validated and the pathological factors which influence CFVR in patients with angiographically normal coronary arteries were analyzed. CFVR was determined successfully in left anterior descending artery (LAD) in 37 of 40 patients with angiographically normal coronary arteries (men 22, women 15, age 20-75 years, mean age 54 +/- 12 years). Coronary flow velocity was measured in the distal LAD by TTDE with contrast enhancement at baseline and during intravenous adenosine infusion of 140 microg/kg per min within 48 h after ICD technique. Average peak velocity at baseline (APVb), average peak velocity during hyperemia (APVh) and CFVR determined from TTDE were correlated closely with those from ICD measurements (APVb: y = 0.64x + 5.04, r = 0.86, P0.001; APVh: y = 0.63x + 14.36, r = 0.82, P0.001; CFVR: y = 0.65x + 0.92, r = 0.88, P0.001). For CFVR measurements, the mean differences between TTDE and ICD methods were 0.12 +/- 0.39. CFVR in patients with history of hypertension was significantly lower than that in patients without history of hypertension (P0.05). Intravascular ultrasound (IVUS) was performed in 34 patients. Plaque formation was found in LAD by IVUS in 17 (50%) patients. No significant difference in CFVR was found between the patients without plaque formation (3.11 +/- 0.49) and those with plaque formation (2.76 +/- 0.53, P = 0.056). It is suggested that TTDE with contrast enhancement provides reliable measurement of APV and CFVR in the distal LAD. The early stage of atherosclerosis could be detected by IVUS, which may be normal in angiography. CFVR is impaired in patients with history of hypertension compared with that in patients without history of hypertension.

Transthoracic Doppler echocardiography (TTDE) allows noninvasive flow measurement in the distal left anterior descending artery (LAD). The feasibility of detecting coronary flow by contrast-enhanced TTDE with second harmonic technique was assessed, the coronary flow velocity reserve (CFVR) was evaluated in comparison to intracoronary Doppler flow (ICD) analysis and the CFVR after PTCA in LAD was investigated. In 77 (96%) of 80 patients, CFVR was successfully determined with intravenous adenosine infusion. Doppler signal quality was evaluated in the first 46 patients by use of intravenous Levovist infusion and second harmonic technique. The Doppler flow was not visible in 1. patient only. CFVR determined from TTDE (2.77 +/- 0.65) was correlated closely with those from ICD (2.88 +/- 0.78) measurements (y = 0.73x + 0.67, r = 0.87, P0.001). In conclusion, TTDE is a feasible method and provides reliable data on CFVR which can be used for follow-up after PTCA.

Background: A postprocedural increase of the serum troponin I concentration (TnI) reflects myocardial injury and occurs frequently during transcatheter aortic valve implantation (TAVI). Periprocedural coronary microembolization is a potential cause of such injury. We therefore evaluated each step of the transfemoral TAVI procedure for coronary embolization using intracoronary Doppler (ICD) in the left anterior descending (LAD) artery. Methods: 15 high-risk patients with severe, symptomatic aortic valve stenosis (age 79 ± 45 yrs; EuroScore 17 ± 4%) who underwent transfemoral TAVI using the balloon-expandable Edwards bioprosthesis were included. ICD examinations were recorded and evaluated off-line for high-intensity transient signals (HITS). Perioperative concentrations of TnI were serially measured within the first 72 h after TAVI, and a cardiac MRI with late gadolinium-enhancement (LGE) was performed within 7 days. Results: HITS were detected in all patients (figure 1), mostly during the initial crossing...

Based on the currently available data, the strategy of routine stent placement in unselected lesions located in small coronary arteries provides good immediate results but is still associated with a high incidence of in-stent restenosis. Randomized trials comparing elective stenting with balloon angioplasty have not provided the demonstration that routine stenting is the best strategy for percutaneous intervention in coronary arteries with a reference diameter smaller than 2.75-3.0 mm. This paper describes the rationale for provisional stenting in this clinical setting and reviews the role of quantitative coronary angiography, intracoronary ultrasound and intracoronary Doppler measurements in the identification of lesions that would benefit from adjunctive stent placement after balloon angioplasty and in guiding stent implantation.

Aims Evaluation of angiographical and intracoronary Doppler-derived parameters of coronary stenosis severity. Methods and Results A total of 225 patients with one-vessel disease were studied before PTCA and at 6 months follow-up. Exercise electrocardiography was performed to document presence (n=157) or absence (n=138) of an ST segment shift (greater than or equal to 0.1 mV). Intracoronary blood flow velocity analysis was performed to determine the proximal/distal flow velocity ratio, the distal diastolic/systolic flow velocity ratio and coronary flow velocity reserve. Receiver operator characteristic curves were calculated to assess the predictive value of these variables compared with the exercise test. The distal coronary flow velocity reserve demonstrated the best linear correlation for both percentage diameter stenosis and minimum lumen diameter (r=0.67 and r=0.66; P Conclusions The distal coronary flow velocity reserve is the best intracoronary Doppler parameter for evaluation of coronary narrowings. Angiographical estimates of coronary lesion severity and distal coronary flow velocity reserve are good and independent predictors for the assessment of functional severity of coronary stenosis, emphasizing the complementary role of these parameters for clinical decision making. (C) 2000 The European Society of Cardiology.

The utility of intra-arterial Doppler flow in assessing internal mammary artery (IMA) bypass grafts has infrequently been reported. Two patients are described in which Doppler evaluation of the IMA graft provided valuable diagnostic information prior to intervention. Also provided is a review of the available literature concerning evaluation of pathology in IMA grafts.

Introduction: Coronary microvascular function can be assessed invasively by combining measurements of coronary pressure and flow. The index of microcirculator resistance (IMR), obtained using therm...

Coronary blood flow velocity measurements during protected left main coronary angioplasty have not been previously reported. In a patient undergoing angioplasty of left main and circumflex vessels with prior coronary artery bypass grafting, distal coronary flow velocity was measured before, during, and after angioplasty, and again after stenting of the circumflex stenosis. The data demonstrated preserved coronary flow during left main occlusion in this individual and provided new observations that highlight the limitations of our understanding of myocardial blood flow in complex circumstances of high risk angioplasty and interventions following bypass graft surgery.

Background and Aims: Physiologic measurement of myocardial perfusion in the immediate postangioplasty period may complement the angiographic assessment of the outcome of the procedure and improve our

This chapter reviews the main noninvasive (TTDE, myocardial contrast echocardiography, PET, and CMR) and invasive (thermodilution, gas wash-out method, intracoronary Doppler recording) methods and techniques proposed to assess coronary microvascular function in the clinical setting and to identify the various mechanisms of CMD. Pros and cons of each method are discussed and compared.

Selective intracoronary thrombolytic therapy has recently been advocated as a technique to recanalize occluded coronary bypass grafts. We report a novel approach for monitoring the results of this treatment utilizing a coronary artery doppler flow guidewire. This approach may optimize the duration of thrombolytic treatment in these patients. © 1995 Wiley-Liss, Inc.

Coronary flow velocity reserve (CVR) is reduced in patients with severe symptomatic aortic stenosis, contributing to ischemic clinical symptoms. We evaluated coronary flow dynamics assessed by intracoronary Doppler surveillance of the blood flow in the left anterior descending (LAD) artery during

Coronary steal due to unligated side branches of an internal mammary artery graft has been reported previously. Embolization of these side branches has been shown to result in symptomatic improvement, but objective evidence of improved flow to the coronary artery has been lacking. We studied intracoronary Doppler flow in a patient presenting with symptoms thought to be due to a large unligated side branch of mammary graft. There was no significant change in the mammary flow after balloon occlusion of the side branch. More objective data may be required to routinely prescribe side branch embolization for symptomatic patients with unligated side branches of a mammary graft.

Background— The Doppler wire–derived (relative) coronary flow velocity reserve (CVR) that is used to evaluate functional significance of a coronary stenosis is a method performed only by interventional cardiologists. An angiographic method would be useful in the diagnostic catheterization laboratory. For this purpose, we investigated the relation between TIMI frame count reserve (FCR) and CVR. Methods and Results— In 38 patients, (relative) FCR of left anterior descending (LAD) and left circumflex coronary artery (LCx) was calculated by using manual, synchronized contrast agent injections and compared with (relative) CVR. In addition, vessel length was measured with an intracoronary guidewire and frame count flow velocity was calculated and compared with average peak velocity. There was a strong correlation between FCR and CVR ( r =0.62, P r =0.84, P P P Conclusion— The (relative) frame count reserve can be used to estimate (relative) coronary flow velocity reserve.

The aim of the study was validation of a mean brightness method and new coronary flow index CFI for the assessment of coronary flow by means of intracoronary Doppler measurements. This method utilizes the dynamics of coronary angiograms and is based on the computer analysis of conventional coronary angiograms. The contractual measure of blood flow is percent change of mean brightness of coronary artery in unit of time: cardiac cycle (%/cycle) or time in seconds (%/sec). Coronary flow was investigated in 10 patients with angiographically normal coronary artery (NCA group) and in 17 patients with single vessel stenosis (SVS group). In the SVS group, measurements were repeated twice: before and after PTCA procedure. In both groups statistically significant, positive correlations were found between both methods. In conclusion, the new CFI is very reliable, simple and easy to obtain parameters able to assess coronary flow and can be very useful in the case of comparative studies.

Introduction Quantitative angiographic assessment after balloon angioplasty is a poor predictor of immediate and long-term outcome. However, the measurement of blood flow velocity during angioplasty has been proved clinically useful. Aims To analyse the value of the maximal stenotic flow velocity and the presence of stenotic flow velocity acceleration (aSV) for the long-term outcome after balloon angioplasty. Methods and Results Patients undergoing single lesion angioplasty within the DEBATE trial were included. aSV was defined as acceleration in the stenotic coronary flow velocity >50% baseline velocity assessed at a reference site of the target vessel. After balloon angioplasty diameter stenosis, minimal lumen diameter (MLD) and coronary flow velocity reserve were similar between the aSV (n=54) and non-aSV group (n = 125). At follow-up, the aSV group had a higher restenosis rate (52% vs 30%, P=0.006). The presence of aSV was the strongest independent predictor of restenosis (OR 3.08, 95% CI 1.35 to 7.05, P=0.008). The best predictive cut-off value of SV was 101 cm.s (-1) (sensitivity of 46%, specificity of 81%, positive predictive value of 85% and a negative predictive value of 58%). Conclusion Following angioplasty, SV appears to be exquisitely sensitive to the changes experienced at the treated area without depending on the status of the microcirculation. (C) 2002 The European Society of Cardiology.

The aim of this study was to evaluate whether coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) in the posterior descending right coronary artery can be reliably measured by transthoracic Doppler echocardiography (TTDE). In 17 patients, CFV in the posterior descending right coronary artery was measured with TTDE at the time of Doppler guidewire examination. CFV was measured by both methods at baseline and under hyperemic conditions. TTDE data were obtained for 12 patients. CFV and CFVR by TTDE show a good correlation with those obtained by the Doppler guidewire method (average diastolic peak velocity: r = 0.98, y = 0.85x + 5.26; diastolic peak velocity: r = 0.97, y = 0.94x + 3.39; CFVR: r = 0.97, y = 0.87x + 0.56). CFV and CFVR in the posterior descending right coronary artery obtained noninvasively by TTDE accurately reflect these values obtained by the invasive Doppler guidewire method.

Coronary flow velocity reserve (CFVR) (maximum/baseline flow velocity, 16 microg adenosine) was compared with dobutamine stress echocardiography (DSE) (5 to 40 microg/kg/min) to assess the progression of angiographically silent cardiac allograft vasculopathy (CAV). As a reference for the morphologic assessment of CAV, serial intracoronary ultrasound (ICUS) measurements were performed. An increase in CFVR could be observed in all transplant patients despite morphologic or functional progression of CAV or non-progressive CAV as assessed by ICUS or DSE. Thus, serial intracoronary Doppler flow analysis is not useful to predict morphologic or functional progression of CAV.

Aims This study was conducted to analyse flow velocity parameters and predictors of a suboptimal coronary flow reserve ( Methods Two hundred and twenty-five patients underwent sequential intracoronary Doppler as part of the DEBATE I study. Of these, 183, with complete angiography and Doppler at the 6-month follow-up, were included. Univariate and multivariate logistic analysis was performed to identify independent predictors of post-procedural suboptimal coronary flow reserve, defined as coronary flow reserve Results Forty-eight per cent (n=88) of the patients achieved a suboptimal coronary flow reserve. These patients had higher baseline velocities (cm.s(-1)) before balloon angioplasty (18 +/- 9 vs 14 +/- 6, P=0.004), after balloon angioplasty (22 +/- 11 vs 14 +/- 5, P Conclusion A suboptimal coronary flow reserve was associated with (1) a chronically elevated baseline average peak velocity (2) a transient deficit in the hyperaemic average peak velocity (3) the elderly, and female gender.

To the Editor: The article by Werner et al1 in the December 12, 2000, issue of Circulation provides further evidence that the collateral flow index can be used to quantify collaterals and correlates with the presence of preserved myocardial contractile function. This supports Chugh’s hypothesis, which was first put forward in 1997 and was published in the British Journal of Cardiology in 2000.2 Chugh’s hypothesis refers to the use of intracoronary Doppler and pressure …

This study compared the TIMI frame count (TFC), which has been proposed as a method for quantifying coronary blood flow, with coronary flow and microvascular function measured with intracoronary Doppler and intracoronary ultrasound. Coronary blood flow volume was calculated from coronary blood velocity (by intracoronary Doppler) and lumen area (by intracoronary ultrasound) in the LAD in 46 post-heart transplant patients at baseline and after intracoronary adenosine. TFC correlated significantly with average peak coronary blood velocity (r = -0.42; P = 0.004) and coronary lumen area (r = 0.39; P = 0.008), but not with coronary blood flow volume (r = -0.01; P = 0.96) or the coronary flow reserve response to adenosine (r = 0.09; P = 0.58). In conclusion, TFC is a simple method of assessing coronary blood velocity but not volumetric flow. While TFC does not predict coronary flow reserve, as a measure of velocity it does provide an assessment of basal microvascular tone, information that is complementary to that afforded by flow reserve measurements.

Aims Evaluation of angiographical and intracoronary Doppler-derived parameters of coronary stenosis severity. Methods and Results A total of 225 patients with one-vessel disease were studied before PTCA and at 6 months follow-up. Exercise electrocardiography was performed to document presence (n=157) or absence (n=138) of an ST segment shift (greater than or equal to 0.1 mV). Intracoronary blood flow velocity analysis was performed to determine the proximal/distal flow velocity ratio, the distal diastolic/systolic flow velocity ratio and coronary flow velocity reserve. Receiver operator characteristic curves were calculated to assess the predictive value of these variables compared with the exercise test. The distal coronary flow velocity reserve demonstrated the best linear correlation for both percentage diameter stenosis and minimum lumen diameter (r=0.67 and r=0.66; P Conclusions The distal coronary flow velocity reserve is the best intracoronary Doppler parameter for evaluation of coronary narrowings. Angiographical estimates of coronary lesion severity and distal coronary flow velocity reserve are good and independent predictors for the assessment of functional severity of coronary stenosis, emphasizing the complementary role of these parameters for clinical decision making. (C) 2000 The European Society of Cardiology.

Quantitative coronary angiography (QCA) and intracoronary ultrasound (ICUS) are methods for anatomic assessment of stent deployment. Intracoronary Doppler is primarily a method for the physiologic assessment of coronary stenoses. It correlates well with traditional noninvasive measurements of lesion significance. Intracoronary Doppler was used for the anatomic assessment of de novo coronary artery stenosis with variable success; however, its use for anatomic assessment of adequate stent deployment is unavailable. A rapid, automated software program was developed based on a modified continuity equation to calculate the maximal in-stent percent area stenosis by comparing the maximal in-stent velocity to an average reference velocity (proximal and distal). This study was designed to compare the Doppler method of an anatomic assessment with QCA and ICUS in 15 patients. Physiologic success of stent deployment was determined by the distal coronary flow reserve to 24 to 36 microg of intracoronary adenosine. Following successful stent deployment, distal coronary flow reserve increased significantly from a baseline of 1.6 +/- 0.5 to 2.9 +/- 1.1. There was a significant correlation between the maximal in-stent percent area stenosis as measured by Doppler and both QCA (r = 0.78, p0.01) and ICUS (r = 0.84, p0.01). This study demonstrates that maximal in-stent percent area stenosis can be measured by intracoronary Doppler and a novel software program. The intracoronary Doppler guidewire method can assess the adequacy of stent deployment using both anatomic and physiologic principles and may supplement other quantitative methodologies.

To the Editor: In the July 1, 1997, issue of Circulation , Piek and coworkers1 provided very interesting intracoronary data on the pharmacological responsiveness of the human coronary collateral circulation. In 38 patients with 1-vessel coronary artery disease and visible (n=24) or recruitable (n=14) collaterals, a collateral flow index, indices for collateral resistance, and index for the resistance in the vascular bed downstream of the collateral receiving artery were investigated regarding their response to intracoronary adenosine or nitroglycerin injected into the collateral donor artery. The authors found that spontaneously visible and recruitable collaterals substantially differed in their response to intracoronary adenosine or nitroglycerin in that the former were able to decrease their resistance and thus increase the flow through it, whereas the latter were unable to do so. Although the direct study of collateral hemodynamics in humans is very important because almost no data exist in this area of research, the mentioned results of the present study have to be taken cautiously for some methodological reasons. 1. The authors’ assertion is incorrect that they obtained collateral flow by measuring diastolic occlusive time velocity …

Percutaneous transluminal coronary angioplasty has achieved a dominant role for the treatment of patients with coronary artery disease. In several European countries and the US the number of angioplasty procedures has exceeded the number of coronary artery bypass graft operations[1, 2].