Intracoronary Doppler Research Articles

Myocardial Bridging

An epicardial segment of a coronary artery that courses through the myocardium is termed "myocardial bridging". Generally, this is a benign condition but it may lead to angina, ischemia or infarction. The current diagnostic standard of reference is coronary catheter angiography. Intravascular ultrasound (IVUS) and intracoronary Doppler (ICD) have been recently introduced as well. These are all invasive imaging modalities. We describe the utilization of gated multidetector CT (MDCT) as a non-invasive alternative for diagnosis of this anomaly. Information regarding the tunneled coronary artery including its length, depth, precise location and surrounding myocardium is easily obtainable.

The quantification of absolute myocardial perfusion in humans by contrast echocardiography: Algorithm and validation

We sought to test whether myocardial blood flow (MBF) can be quantified by myocardial contrast echocardiography (MCE) using a volumetric model of ultrasound contrast agent (UCA) kinetics for the description of refill curves after ultrasound-induced microsphere destruction. Absolute myocardial perfusion or MBF (ml.min(-1).g(-1)) is the gold standard to assess myocardial blood supply, and so far it could not be obtained by ultrasound. The volumetric model yielded MBF = rBV.beta/rho(T), where rho(T) equals tissue density. The relative myocardial blood volume rBV and its exchange frequency beta were derived from UCA refill sequences. Healthy volunteers underwent MCE and positron emission tomography (PET) at rest (group I: n = 15; group II: n = 5) and during adenosine-induced hyperemia (group II). Fifteen patients with coronary artery disease underwent simultaneous MCE and intracoronary Doppler measurements before and during intracoronary adenosine injection. In vitro experiments confirmed the volumetric model and the reliable determination of rBV and beta for physiologic flow velocities. In group I, 187 of 240 segments were analyzable by MCE, and a linear relation was found between MCE and PET perfusion data (y = 0.899x + 0.079; r(2) = 0.88). In group II, resting and hyperemic perfusion data showed good agreement between MCE and PET (y = 1.011x + 0.124; r(2) = 0.92). In patients, coronary stenosis varied between 0% to 89%, and myocardial perfusion reserve was in good agreement with coronary flow velocity reserve (y = 0.92x + 0.14; r(2) = 0.73). The volumetric model of UCA kinetics allows the quantification of MBF in humans using MCE and provides the basis for the noninvasive and quantitative assessment of coronary artery disease.

Normal Coronary Physiology Assessed by Intracoronary Doppler Ultrasound

There is a natural need to measure flow in normal as well as diseased coronary arteries since the reestablishment of normal flow is the aim of most coronary interventions. Miniaturization has enabled positioning both proximal and distal within the coronary anatomy and improved accuracy of Doppler velocity measurements. Measurement of coronary flow reserve adds functional data to coronary angiographic anatomic description, and quantitation of flow, achieved by combining Doppler velocity. Although new techniques involving transthoracic Doppler and magnetic resonance imaging are currently being developed and refined to measure coronary flow velocity and volume flow noninvasively, the role of intracoronary Doppler remains secure particularly for the coronary interventional physician.

Collaterals and the recovery of left ventricular function after recanalization of a chronic total coronary occlusion

A good collateral function in patients with regional myocardial dysfunction may indicate viability with the potential for left ventricular (LV) recovery after revascularization of a chronic total coronary occlusion (CTO). A CTO (duration > 2 weeks) was successfully recanalized in 126 patients. During this procedure, the collateral function was assessed before the first balloon inflation by intracoronary Doppler and pressure wires. Collateral function indexes were calculated. Left ventricular function was assessed by the LV ejection fraction (LVEF) and the wall motion severity index (WMSI [SD/chords]). A repeat angiography was available in 119 patients after 4.9 +/- 1.4 m. An improvement of WMSI > or =1 SD/chord was considered significant. Left ventricular function was normal in 42%, regional dysfunction with LVEF > or = 0.60 was observed in 16%, and regional dysfunction with LVEF < 0.60 in 42%. The former had a better collateral function than patients with LV dysfunction. In 39% of patients with LV dysfunction, a significant myocardial recovery was observed at follow-up. The collateral function was similar in patients with and without recovery. However, patients with recovery had a lower peripheral resistance as an indicator of a better preserved microvascular integrity. Recovery of impaired LV function after revascularization of a CTO is not directly related to the quality of collateral function, as collateral development does not appear to require the presence of viable myocardium. However, a preserved microvascular integrity may be of relevance for myocardial recovery.

Bone Marrow-Derived Cell Mobilization with G-CSF and GM-CSF in Patients with Acute Myocardial Infarction: A Pilot Study on Feasibility, Safety and Efficacy.

Introduction. Intracoronary or intramyocardiac injection of bone marrow stem cells or growth factor-mobilized peripheral blood stem cells (PBSC) may contribute to myocardial regeneration and neovascularization of the ischemic myocardium either in animal models or in human. This effect is probably due to a selective colonization of the ischemic area by PBSC. Very few studies were done in the acute setting of ischemic heart disease, with controversial results. Aims of this pilot study were: i) to verify feasibility and safety of PBSC mobilization in patients with acute myocardial infarction (AMI); ii) to monitor clinical effects of PBSC mobilization in terms of global and segmental myocardial perfusion and function.Patients and methods. Eight male patients (mean age: 51,7±5,6 years) were enrolled. All were treated with a primary percutaneous transluminal coronary angioplasty (PTCA) for an anterior (5 patients) or an inferior (3 patients) AMI. The mobilization regimen consisted of G-CSF 5 μg/kg/12h from day 1 to day 3 and GM-CSF 2.5 μg/kg/24h from day 1 to day 5 (starting within 24 hours from PTCA). Since transient severe hypotension was noticed in the first three patients, the protocol was amended by reducing and tapering GM-CSF administration (2.5 μg/kg/24h at days 3, 5, 7). All patients underwent coronary angiography, intracoronary doppler flow study, echocardiography, and nuclear Thallium scan before treatment and at 6 months apart.Results. WBC and PBSC peaked during the 3th day of mobilization. Mean WBC and PBSC peaks were 34960± 10794 leukocytes/μL and 29.71± 30.8 CD34+/μL. Five in hospital adverse events were recorded: severe hypotension in 3 patients (as previously mentioned), atrial fybrillation in 1 patient, recurrent ischemia in 1 patients. No death was observed. At present 7 patients completed a 6-months follow-up evaluation: target lesion revascularization rate was 14,3% (1 patient) and target vessel revascularization rate was 42,8% (3 patients). Angiographic mean ejection fraction increased from 49,8±11,9 to57,1±8,9 (p=NS), and mean coronary flow reserve raised from 1,63±0,42 to 2,45±0,36 (p=0,005). Perfusion improvement was observed by nuclear study in 66% of patients.Conclusions. We conclude that: a) cytokine-induced stem cell mobilization is feasible in AMI patients with adequate GM-CSF administration; b) myocardial perfusion appears to improve within the first six months of follow-up; c) the 3 cases of progressive coronary disease give a concern about a potential negative effect of hematopoietic cytokines (particularly GM-CSF) on silent coronary lesions. However, PBSC mobilization using G-CSF only is worthwhile of further investigation.

Diabetic dyslipidemia and exercise affect coronary tone and differential regulation of conduit and microvessel K+ current

Spontaneous transient outward K(+) currents (STOCs) elicited by Ca(2+) sparks and steady-state K(+) currents modulate vascular reactivity, but effects of artery size, diabetic dyslipidemia, and exercise on these differentially regulated K(+) currents are unclear. We studied the conduit arteries and microvessels of male Yucatan swine assigned to one of three groups for 20 wk: control (C, n = 7), diabetic dyslipidemic (DD, n = 6), or treadmill-trained DD animals (DDX, n = 7). Circumflex artery blood flow velocity obtained with intracoronary Doppler and lumen diameters obtained by intravascular ultrasound enabled calculation of absolute coronary blood flow (CBF). Ca(2+) sparks were determined in pressurized microvessels, and perforated patch clamp assessed K(+) current in smooth muscle cells isolated from conduits and microvessels. Baseline CBF in DD was decreased versus C. In pressurized microvessels, Ca(2+) spark activity was significantly lower in DD versus C and DDX (P < 0.05 vs. DDX). STOCs were pronounced in microvessel (approximately 35 STOCs/min) in sharp contrast to conduit cells ( approximately 2 STOCs/min). STOCs were decreased by 86% in DD versus C and DDX in microvessels; in contrast, there was no difference in STOCs across groups in conduit cells. Steady-state K(+) current in microvessels was decreased in DD and DDX versus C; in contrast, steady-state K(+) current in conduit cells was decreased in DDX versus DD and C. We conclude that steady-state K(+) current and STOCs are differentially regulated in conduit versus microvessels in health and diabetic dyslipidemia. Exercise prevented diabetic dyslipidemia-induced decreases in baseline CBF, possibly via STOC-regulated basal microvascular tone.

Insulin sensitivity and coronary vasoreactivity: insulin sensitivity relates to adenosine‐stimulated coronary flow response in human subjects

Diabetes is associated with coronary microvasculature abnormalities and impaired coronary flow reserve (CFR). CFR is the ratio of coronary flow under maximal vasodilation to basal flow and is a measure for coronary vasoreactivity. Insulin resistance is the central defect in the development of type 2 diabetes, preceding its onset by 10-20 years. Thus, the relationship between insulin sensitivity and CFR in nondiabetic subjects is particularly interesting. The aim of the study was to investigate this relationship. Cross-sectional study. The study population consisted of 18 nondiabetic subjects without coronary artery stenosis on coronary angiography. We excluded patients with structural heart disease or with conditions affecting CFR or insulin sensitivity such as low density lipoprotein (LDL)-cholesterol > or = 4.14 mmol/l, smoking, hypertension or obesity with a body mass index (BMI) > 28 kg/m(2). CFR was 3.1 +/- 0.8 (range 1.7-4.8), as assessed by intracoronary Doppler measurements in the left anterior descending coronary arteries after adenosine stimulation. Intravascular ultrasound revealed zero to moderate coronary atherosclerotic changes. Whole-body insulin sensitivity (M-value) was 7.5 +/- 2.9 mg/kg/min (range 2.2-12.6), as assessed by the hyperinsulinaemic-euglycaemic clamp test. Subjects with low CFR (< 3.0) had a significantly lower M-value than subjects with normal CFR (> 3.0) (6.0 +/- 2.5 vs. 9.0 +/- 2.5 mg/kg/min, P = 0.021). Univariate linear regression demonstrated a strong correlation between CFR and M-value (r = 0.76, P < 0.001). In multiple regression analysis, the significant association of CFR with M-value was independent of potential confounders (sex, age, BMI, LDL-cholesterol and plaque burden on intravascular ultrasound). Bootstrap analysis corroborated this finding. Whole-body insulin sensitivity relates to coronary vasoreactivity. Across a wide range of both insulin sensitivity and coronary flow reserve from markedly abnormal to normal values, an increase in insulin sensitivity appears to be associated with an increase in coronary flow reserve. Insulin resistance is therefore associated with coronary microvasculature abnormalities in nondiabetics.

Estimation of coronary flow reserve by Tc-99m sestamibi imaging in patients with coronary artery disease: Comparison with the results of intracoronary Doppler technique

This study compared coronary flow reserve (CFR) estimated by technetium 99m sestamibi imaging with the results obtained with intracoronary Doppler in patients with coronary artery disease. Intraobserver and interobserver reproducibility of the radionuclide-estimated CFR was also assessed. Fourteen consecutive patients (mean age, 54 +/- 7 years) with documented coronary artery disease in whom percutaneous coronary intervention was planned underwent dipyridamole (0.74 mg/kg) sestamibi imaging and intracoronary Doppler within 5 days. Myocardial blood flow (MBF) was estimated by measurement of first transit counts in the pulmonary artery and myocardial counts from single photon emission computed tomography images. Estimated CFR was expressed as the ratio of stress MBF to rest MBF. In the study vessels, CFR was 1.36 +/- 0.43 as estimated by sestamibi and 1.39 +/- 0.42 by intracoronary Doppler ( P = .69). A significant relationship between CFR estimated by sestamibi and CFR obtained by intracoronary Doppler was observed ( r = 0.85, P < .001). On Bland-Altman analysis, the mean difference between CFR by sestamibi and by Doppler was 0.03 and the intraclass correlation coefficients for intraobserver and interobserver reproducibility were high (all P < .001) for both global and regional CFR. This study demonstrates a good agreement between CFR estimated by sestamibi imaging and by intracoronary Doppler results and a lack of intraobserver and interobserver variability of this noninvasive approach.

Coronary flow and flow reserve in children

Aortic blood pressure affects coronary blood flow, but within the normal physiological blood pressure range coronary blood flow is constant. The coronary flow is pulsatile, being maximal in the early diastole. There is a smaller systolic flow component. The low systolic pressure in the right ventricle favours systolic flow. The proportion of systolic flow is greater in the right than in the left coronary artery. Heart diseases in children cause several haemodynamic and functional changes that are likely to affect myocardial perfusion. Newborns with severe valvular aortic stenosis may have a retrograde systolic flow in the left coronary artery. Children with dilated cardiomyopathy have a reduced coronary flow related to myocardial mass. Coronary flow reserve (CFR) is defined as the ratio of maximal coronary blood flow, as induced by reactive hyperaemia or administration of vasodilators, divided by resting flow. Coronary flow can normally increase 2.5–4‐fold. CFR is reduced if basal flow is increased due to myocardial hypertrophy, strain or hypoxaemia. Very low CFR values measured with positron emission tomography are reported in neonates with surgically treated congenital heart disease. Measurement of coronary flow velocity with the intracoronary Doppler guide wire may be regarded as a reference or “gold standard” in the evaluation of coronary flow velocity and CFR. Conclusions: Coronary flow and CFR in children is a largely unexploited field, and has vast potential for future research.

Coronary flow and flow reserve in children

Aortic blood pressure affects coronary blood flow, but within the normal physiological blood pressure range coronary blood flow is constant. The coronary flow is pulsatile, being maximal in the early diastole. There is a smaller systolic flow component. The low systolic pressure in the right ventricle favours systolic flow. The proportion of systolic flow is greater in the right than in the left coronary artery. Heart diseases in children cause several haemodynamic and functional changes that are likely to affect myocardial perfusion. Newborns with severe valvular aortic stenosis may have a retrograde systolic flow in the left coronary artery. Children with dilated cardiomyopathy have a reduced coronary flow related to myocardial mass. Coronary flow reserve (CFR) is defined as the ratio of maximal coronary blood flow, as induced by reactive hyperaemia or administration of vasodilators, divided by resting flow. Coronary flow can normally increase 2.5-4-fold. CFR is reduced if basal flow is increased due to myocardial hypertrophy, strain or hypoxaemia. Very low CFR values measured with positron emission tomography are reported in neonates with surgically treated congenital heart disease. Measurement of coronary flow velocity with the intracoronary Doppler guide wire may be regarded as a reference or "gold standard" in the evaluation of coronary flow velocity and CFR. Coronary flow and CFR in children is a largely unexploited field, and has vast potential for future research.

Determinants of coronary blood flow in humans: quantification by intracoronary Doppler and ultrasound

The direct determinants of coronary flow are lumen area and blood flow velocity; however, the precise mechanisms that control these factors are not fully understood. The aim of the present study was to assess by which mechanisms lumen area and coronary flow velocity interact with hemodynamic and morphometric factors, thereby influencing coronary flow. Intracoronary Doppler and ultrasound measurements were performed in 28 patients without coronary lumen irregularities. Flow velocity and lumen cross-sectional area were measured in the proximal segments of all three coronary arteries. Global lumen cross-sectional area and global flow were obtained by adding up the values of all three coronary arteries. Left ventricular mass was assessed by echocardiography. Stress-mass-heart rate and pressure-rate products reflecting myocardial oxygen demand were calculated. Global coronary flow increased during adenosine-induced hyperemia from 197 +/- 72 to 637 +/- 204 ml/min (P < 0.001). Global coronary flow closely correlated with the stress-mass-heart rate product (r = 0.62; P < 0.001). Looking at the two constituents of flow separately, global coronary cross-sectional area was closely related to left ventricular muscle mass (r = 0.61; P < 0.001), whereas mean coronary flow velocity at rest showed a strong linear relation with the pressure-rate product (r = 0.64; P < 0.001). There was no interaction between cross-sectional area and blood flow velocity in any of the coronary vessels. Coronary lumen size and flow velocity, the two determinants of coronary flow, are principally determined by different physiological factors. Long-term flow adaptation is achieved by an increase in coronary lumen size, whereas short-term myocardial oxygen requirements are met by changes in resting flow velocity.

Posterior Descending Coronary Artery Flow Reserve Assessment by Doppler Echocardiography in Children with and without Congenital Heart Defect Comparison with Invasive Technique

To evaluate whether transthoracic Doppler echocardiography can reliably measure coronary flow velocity and coronary flow velocity reserve (CFVR) in the posterior descending coronary artery (PD) in children, we examined 32 patients who had congenital heart disease (ventricular septal defect in 10, tetralogy of Fallot in 6, tricuspid atresia in 3, double-outlet right ventricle in 2, patent ductus arteriosus in 2, and aortic valve stenosis in 2) and 7 patients who had a history of Kawasaki disease without stenosis or aneurysm formation of the coronary artery. Average peak flow velocity (APV) in the PD was measured by transthoracic Doppler echocardiography at the time of intracoronary Doppler study. CFVR was defined as the ratio of hyperemic to basal APV. Clear envelopes of basal and hyperemic APV in the PD were obtained in 23 of 32 patients by transthoracic Doppler echocardiography. APV obtained from transthoracic Doppler echocardiography correlated highly with that from the Doppler guidewire method (r=0.91). The mean difference between transthoracic Doppler echocardiography and the Doppler guidewire method was 0.1+/-2.9. There was an excellent correlation between transthoracic Doppler echocardiography and the Doppler guidewire method for the measurements of CFVR (r=0.84). The mean difference between transthoracic Doppler echocardiography and Doppler guidewire was -0.016+/-0.198. Noninvasive measurement of coronary flow velocity and CFVR in the PD using transthoracic Doppler echocardiography accurately reflects invasive measurement of coronary flow velocity and CFVR by the Doppler guidewire method in pediatric patients with various heart diseases.

The EchoMap System:

The EchoMap system allows online integration of intravascular ultrasound (IVUS) and intracoronary Doppler (ICD) images into angiographic images during catheterization, providing exact localization of the IVUS transducer and the ICD wire tip position. Although this is a major advance, the use of the system could lead to more angiographic documentation sequences and enhanced radiation exposure. We investigated the influence of system use on radiation and procedure parameters. During a 22-month period, 794 patients underwent coronary angiography with simultaneous performance of IVUS and/or ICD. The EchoMap system was applied in 392 patients ("EchoMap group"), the remaining 402 patients formed the "No-EchoMap group." Multivariate regression analysis showed no independent association between the use of EchoMap and fluoroscopy time (14.7 +/- 8.5 minutes in the EchoMap group vs 14.5 +/- 10 minutes in the No-EchoMap group, P = NS) or dose area product (7589 +/- 4916 in the EchoMap group vs 7031 +/- 5434 cGy x cm(2), P = NS). EchoMap use was significantly associated with a moderate increase in contrast media amount (392 +/- 162 in the EchoMap vs 356 +/- 155 mL in the No-EchoMap group, P = 0.001). In conclusion, the use of the EchoMap system had no significant influence on radiation exposure during cardiac catheterization, whereas it was associated with a moderate increase in contrast media amount.

Determination of the coronary flow reserve of the LAD in patients with HOCM using the intracoronary Doppler catheter.

Hypertrophic obstructive cardiomyopathy (HOCM) is still a serious problem that is characterized by an increasing hypertrophy of the cardiac muscle. The aim of this study was to investigate the hypothesis whether in HOCM the coronary flow reserve in the left anterior descending artery (LAD) is influenced by pharmacologic stimulation or stimulation using a pacemaker. The study was carried out in 15 patients (6 male, 9 female) with the typical echocardiographic signs of HOCM without coronary artery disease. Using an intracoronary Doppler catheter the average peak velocity and the absolute coronary flow reserve were determined in the proximal, medial and distal part of the LAD under influence of Papaverine, Substance P and under pacemaker stimulation. The coronary square plane was calculated angiographically under the influence of Substance P. Moreover, the retrograde flow was studied and the coherence between the increase of the coronary square plane and the coronary flow reserve were investigated. For statistical analysis the mean value, the standard error of the mean, Spearman's correlation coefficient and the t-test were calculated. Under pharmacologic stimulation higher values in the average peak velocity were observed compared to pacemaker stimulation. A retrograde flow was observed in 8 out of 10 patients. The coronary flow reserve was higher under pharmacologic influence than under pacemaker stimulation. A coherence between the increase of the coronary square plane and the coronary flow reserve was not found. So far, from the published data concerning the characteristics of coronary flow in HOCM patients, only the retrograde flow was reproducible in our patient group. However, a decrease of the coronary flow reserve compared to a healthy control group of the literature could not be observed. Nevertheless ischemia in the subordinate vessels and on the base of microcirculation cannot be excluded.

Effect of estrogen on coronary vasoconstriction in patients undergoing coronary angioplasty

Background Estrogen has an antioxidant potential which may contribute to its cardioprotective effect. We sought to determine whether estrogen administration can affect coronary vasomotor tone in patients after angioplasty by reducing 8- iso-prostaglandin (PG) F 2α concentrations, a bioactive product of lipid peroxidation. Methods The study was designed to prospectively investigate 30 consecutive patients scheduled for elective coronary angioplasty. Patients were randomized into two groups according to whether they did not (group 1, n=15) or did have (group 2, n=15) intracoronary (i.c.) treatment with estrogen prior to coronary angioplasty. Results There were no significant differences of collateral circulation assessed by intracoronary Doppler flow velocity during balloon inflations between the study groups. The diameters of the coronary artery at the dilated and distal segments were significantly reduced 15 min after dilation compared with those immediately after dilation in group 1 (both P<0.0001). The vasoconstriction was significantly blunted in group 2. The 8- iso-PGF 2α levels in plasma from the coronary sinus rose significantly from 194±45 to 390±97 pg/ml ( P<0.0001, 95% confidence intervals=142–249 pg/ml) 15 min after angioplasty in group 1, which was attenuated after administering estrogen. Significant correlation was found between the changes of coronary vasomotion of the dilated segment and 8- iso-PGF 2α levels in group 1 (r=0.73, P=0.002). Conclusions 8- iso-PGF 2α is released into the coronary circulation during angioplasty, and this vasoactive substance may contribute to the occurrence of vasoconstriction. Estrogen administration attenuated vasoconstriction by reducing the 8- iso-PGF 2α levels. This finding may provide a new strategy to treat coronary vasoconstriction after angioplasty.

Coronary microvascular dysfunction in patients with symptomatic hypertrophic cardiomyopathy

Background: Patients with hypertrophic cardiomyopathy (HCM) have been shown to have reduced myocardial perfusion in the presence of normal epicardial arteries. The mechanism of abnormal microvascular function is not well understood. Hypothesis: A possible mechanism for the reduction in CFR may be that the microcirculation is already near maximal dilation in the basal state and is therefore limited in the ability to further dilate and compensate for the increase in myocardial demand. Methods: Eight patients with symptomatic HCM and eight age- and sex-matched controls were studied. All patients underwent coronary angiography and coronary hemodynamic assessment with an intracoronary Doppler wire to determine total coronary blood flow, coronary resistance, and coronary flow reserve (CFR). Phasic blood flow parameters were also obtained. Results: Compared with controls (n = 8), patients with HCM (n = 8) had higher coronary blood flow (52±19 versus 33±11 mL/min, P = 0.03), lower coronary resistance (2.12±0.91 versus 3.13±0.93 mm Hg/mL/min, P = 0.05), and lower CFR (2.1±0.7 versus 3.4±1.0 mm, P = 0.02). There was a direct correlation between CFR and coronary resistance (r = .5, P = .05). HCM patients also had abnormal phasic coronary flow characteristics with lower systolic velocities or reversal of flow during systole, and a more rapid deceleration of diastolic blood flow (40.7±13.2 versus 27.5±8.5 cm/sec2, P=.03). Conclusion: The reduction of CFR in HCM patients may be secondary to near maximal vasodilatation of the microcirculation in the basal state rather than narrowing of intramyocardial small arteries. Symptomatic HCM patients also have abnormal phasic coronary blood flow with a greater dependence on diastolic flow and a more rapid deceleration of diastolic blood flow.

Coronary flow characteristics after a Bentall procedure with or without sinuses of Valsalva.

The sinuses of Valsalva are known to contribute to the normal function of the aortic valve. Little is known about their role in promoting coronary artery blood flow. The aim of this study was to compare coronary artery flow characteristics among patients undergoing a Bentall operation by means of a conventional cylindrical Dacron conduit or with a new conduit with pseudosinuses of Valsalva or in patients retaining their natural sinuses of Valsalva after aortic valve and supracoronary ascending aorta replacement. One year after a Bentall procedure with a standard cylindrical Dacron conduit (7 patients, group A) or with the new conduit (7 patients, group B), or after aortic valve and ascending aortic replacement (control group, 7 patients, group C) coronary flow velocity reserve and diastolic to systolic time integral ratio at baseline and after maximal hyperemia (with 40 microg of adenosine) were assessed by using a 0.014-in. Doppler guidewire positioned in the middle portion of the left anterior descending coronary artery. All patients were in NYHA class I, sinus rhythm and free of coronary disease. Arterial blood pressures and heart rate were comparable among groups. Intracoronary Doppler measurements did not show any significant difference in coronary vascular reserve between the three groups (3.6+/-0.4 vs 3.1+/-0.7 vs 3.7+/-0.5, P = 0.2). A greater diastolic component at baseline was present in group B patients (5.5+/-1.9 vs 3.5+/-0.9 in group A and 3.7+/-0.9 in group C, P = 0.024). After maximal hyperemia the diastolic component increased slightly in group A patients (8%) while both in groups B and C significantly decreased (-15 and -20%, respectively) (P = 0.017). The presence of pseudosinuses of Valsalva does not influence coronary flow reserve. After maximal coronary vasodilation the increase in the systolic component of coronary flow is more evident in the presence of sinuses or pseudosinuses of Valsalva, thus suggesting that coronary flow pattern may be affected by the presence of sinuses.

Coronary resistance system in evaluation of microvascular dysfunction after intracoronary microembolization: an experimental study

To assess the microvascular function of coronary artery after intracoronary microembolization using coronary resistance system. The left anterior descending coronary artery (LAD) of 10 pigs weighing 21 kg-25 kg were embolized by repetitive injection of microspheres 45 micro m in diameter through a 2.8F Tracker catheter. Intra-vascular ultrasound (IVUS) images, intracoronary Doppler and pressure signals in the middle segment of LAD were acquired by use of intracoronary ultrasound imaging catheter, Doppler flow wire and pressure wire separately. Intracoronary bolus injection of 18 micro g adenosine was administered to maximally vasodilate the coronary arterial bed through the 2.8F Tracker catheter. The resting and hyperemic signals were acquired respectively before microembolization and in different levels of microembolization. Coronary resistance system reflecting the resistance to pulsatile coronary flow was established by a self-made software of PC system. The resting and hyperemic CR parameters included average resting coronary resistance (rCR) and average minimal coronary resistance (min-CR), the first-harmonic rCR and min-CR, the first-harmonic rCR orientation and min-CR orientation, and so on. Factor analysis was performed to extract the best coronary parameter from the coronary resistance parameters. Factor analysis showed that the first-harmonic rCR and first-harmonic min-CR were correlated better with the first component extracted from the resting and hyperemic CR parameters than rCR and min-CR, with the correlation coefficient being 0.913 and 0.950 in the first-harmonic CR and first-harmonic min-CR respectively. No significant difference in min-CR was found between the value at the dosage of 5 x 10(4) microspheres and that before microembolization. The min-CR value increased markedly from 271 mm Hg.ml(-1).s(-1) +/- 99 mm Hg.ml(-1).s(-1) at the dosage of injecting 5 x 10(4) microspheres to 361 mm Hg.ml(-1).s(-1) +/- 158 mm Hg.ml(-1).s(-1) at the dosage of injecting 10 x 10(4) microspheres (P < 0.05). The min-CR value remained almost unchanged from the dosage of 10 x 10(4) to 15 x 10(4) microspheres. There was no significant difference concerning the first-harmonic min-CR between the value at the dosage of 5 x 10(4) microspheres and that before microembolization. Along with the increase of number of microspheres injected the min-CR value increased gradually. The min-CR value was increased significantly than that before microembolization since the number of microspheres injected surpassed 14 x 10(4). The first-harmonic min-CR reflected the coronary microvascular dysfunction in different extents of microembolization better than min-CR. The extent of coronary microvascular dysfunction wasn't linearly related to the extent of microembolization.

1026-55 In vitro detection and quantification of high intensity transient signals by using intracoronary doppler ultrasound: A new approach to detect coronary microembolization

1026-55 In vitro detection and quantification of high intensity transient signals by using intracoronary doppler ultrasound: A new approach to detect coronary microembolization

Abnormal coronary vasomotion as a prognostic indicator of cardiovascular events in women: results from the National Heart, Lung, and Blood Institute-Sponsored Women's Ischemia Syndrome Evaluation (WISE).

Coronary vascular dysfunction has been linked to atherosclerosis and adverse cardiovascular outcomes in men, but these relationships have not been firmly established in women. As part of the Women's Ischemia Syndrome Evaluation (WISE) sponsored by the National Heart, Lung, and Blood Institute, 163 women referred for clinically indicated coronary angiography underwent coronary reactivity assessment with quantitative coronary angiography and intracoronary Doppler flow before and after intracoronary administration of acetylcholine, adenosine, and nitroglycerin and were then followed up for clinical outcomes. History of hypertension was present in 61%, dyslipidemia in 54%, diabetes in 26%, and current tobacco use in 21% of women enrolled. Seventy-five percent had no or only mild epicardial coronary artery disease (CAD). Over a median follow-up of 48 months, events occurred in 58 women. On bivariate analysis, women with an event had significantly less change in coronary cross-sectional area (DeltaCSA) in response to acetylcholine (P=0.0006) and nitroglycerin (P=0.04). In addition, women with abnormal coronary dilator response to acetylcholine had less time free from cardiovascular events (P=0.004). In multivariable analysis, after controlling for age, hypertension, diabetes, dyslipidemia, tobacco use, and CAD severity, %DeltaCSA with acetylcholine (P=0.001) independently predicted events. When the outcome was restricted to only death, myocardial infarction, congestive heart failure, and stroke, %DeltaCSA with acetylcholine remained a significant predictor (P=0.006). In women in this study, impaired coronary vasomotor response to acetylcholine was independently linked to adverse cardiovascular outcomes regardless of CAD severity.