Assessment of mitral regurgitation severity by Doppler color flow mapping of the vena contracta

BACKGROUND: Although Doppler color flow mapping is widely used to assess the severity of mitral regurgitation (MR), a simple, accurate, and quantitative marker of MR by color flow mapping remains elusive. We hypothesized that vena contracta width by color flow mapping would accurately predict the severity of MR. METHODS AND RESULTS: We studied 80 patients with MR. Vena contracta width was measured in multiple views with zoom mode and nonstandard angulation to optimize its visualization. Flow volumes across the left ventricular outflow tract and mitral annulus were calculated by pulsed-Doppler technique to determine regurgitant volume. Effective regurgitant orifice area was calculated by dividing the regurgitant volume by the continuous-wave Doppler velocity-time integral of the MR jet. The cause of MR was ischemia in 24, dilated cardiomyopathy in 34 mitral valve prolapse in 12, endocarditis in 2, rheumatic disease in 2, mitral annular calcification in 1, and uncertain in 5. Regurgitant volumes ranged from 2 to 191 mL. Regurgitant orifice area ranged from 0.01 to 1.47 cm2. Single-plane vena contracta width from the parasternal long-axis view correlated well with regurgitant volume (r = .85, SEE = 20 mL) and regurgitant orifice area (r = .86, SEE = 0.15 cm2). Biplane vena contracta width from apical views correlated well with regurgitant volume (r = .85, SEE = 19 mL) and regurgitant orifice area (r = .88, SEE = 0.14 cm2). A biplane vena contracta width > or = 0.5 cm was always associated with a regurgitant volume > 60 mL and a regurgitant orifice area > 0.4 cm2. A biplane vena contracta width < or = 0.3 cm predicted a regurgitant volume < 60 mL and a regurgitant orifice area < 0.4 cm2 in 24 of 29 patients. No other parameter, including jet area, left atrial size, pulmonary flow reversal, or semiquantitative MR grade, correlated significantly with regurgitant volume or regurgitant orifice area in a multivariate analysis. CONCLUSIONS: Our results demonstrate that careful color flow mapping of the vena contracta of the MR jet provides a simple quantitative assessment of MR that correlates well with quantitative Doppler techniques.     

Automated assessment of mitral regurgitant volume and regurgitant fraction by a newly developed digital color Doppler velocity profile integration method

Recent development of the automated cardiac flow measurement (ACFM) method has provided automated measurement of stroke volume and cardiac output by spatial and temporal integration of digital Doppler velocity profile data. The purpose of this study was to evaluate the clinical usefulness of the ACFM method using digital color Doppler velocity profile integration in the assessment of mitral regurgitant volume and regurgitant fraction from measurements of both aortic outflow and mitral inflow volumes. We calculated both aortic outflow and mitral inflow volumes from the apical approach with the ACFM and pulsed Doppler (PD) methods in 20 patients with isolated mitral regurgitation. Mitral regurgitant volume and regurgitant fraction were calculated by the following equation: mitral regurgitant volume = (mitral inflow volume) - (aortic outflow volume), % regurgitant fraction = (mitral regurgitant volume)/(mitral inflow volume) x 100. Mitral regurgitant volume and regurgitant fraction were compared with that determined by the PD method. Mitral regurgitant volume measurement by the ACFM method showed a good correlation with that measured by the PD method (r = 0.90, y = 0.77x + 11.6, SEE = 9.0 ml); the mean differences between PD and ACFM measurements was -1.7 +/- 12.5 ml. Regurgitant fraction estimated by the ACFM method correlated well with that of the PD method (r = 0.92, y = 0.98x + 2.1, SEE = 8.8%). The mean difference for the measurement of regurgitant fraction between the PD and ACFM methods was 0.8 +/- 6.6%. Total time required for mitral regurgitant volume calculation in 1 cardiac cycle by the ACFM method was significantly shorter than that of the PD method (126 +/- 15 seconds vs 228 +/- 36 seconds, p <0.01). In conclusion, the newly developed ACFM method is simple, quick, and accurate in the automated assessment of mitral regurgitant volume and regurgitant fraction.     

Rapid estimation of regurgitant volume by the proximal isovelocity surface area method in mitral regurgitation: Can continuous-wave Doppler echocardiography be omitted?

To determine whether heme oxygenase-1 (HO-1) protein is induced by endogenous nitric oxide (NO) in rat glial cultures, we examined the effects of lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), and NO donors such as S-nitroso-N-acetylpenicillamine (SNAP), in mixed glial cells and in vivo rat hippocampus. In cultured glial cells, treatment with LPS induced the expression of 130-kd inducible NO synthase (iNOS) after 6 h, and NO2- accumulation and enhancement of the protein level of 33-kd HO-1 after 12 h. In addition, treatment with SNAP induced HO-1 expression after 6 h. Although NOS inhibitors such as NG-nitro-L-arginine (NNA) and NG-methyl-L-arginine did not change LPS-induced iNOS expression, these inhibitors suppressed both NO2- accumulation and the enhancement of HO-1. Immunocytochemistry showed that treatment with LPS for 24 h induced iNOS immunoreactivity predominantly in ameboid microglia, while this treatment induced HO-1-immunoreactivity in both microglia and astrocytes. In in vivo rat hippocampus, microinjection of LPS plus IFN-gamma, or SNAP after 24 h also induced HO-1 immunoreactivity in reactive microglia and astrocytes. In addition, intraperitoneal administration of NNA inhibited HO-1 immunoreactivity induced by the microinjection of LPS plus IFN-gamma. These results suggest that endogenous NO production by iNOS in microglia causes autocrine and paracrine induction of HO-1 protein in microglia and astrocytes in vitro and in rat brain.     

Color Doppler regurgitant jet area for evaluating eccentric mitral regurgitation: an animal study with quantified mitral regurgitation

OBJECTIVES: The purpose of the present study was to rigorously evaluate the accuracy of the color Doppler jet area planimetry method for quantifying chronic mitral regurgitation. BACKGROUND: Although the color Doppler jet area has been widely used clinically for evaluating the severity of mitral regurgitation, there have been no studies comparing the color jet area with a strictly quantifiable reference standard for determining regurgitant volume. METHODS: In six sheep with surgically produced chronic mitral regurgitation, 24 hemodynamically different states were obtained. Maximal color Doppler jet area for each state was obtained with a Vingmed 750. Image data were directly transferred in digital format to a microcomputer. Mitral regurgitation was quantified by the peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions determined using mitral and aortic electromagnetic flow probes. RESULTS: Mean regurgitant volumes varied from 0.19 to 2.4 liters/min (mean [+/- SD] 1.2 +/- 0.59), regurgitant stroke volumes from 1.8 to 29 ml/beat (mean 11 +/- 6.2), peak regurgitant volumes from 1.0 to 8.1 liters/min (mean 3.5 +/- 2.1) and regurgitant fractions from 8.0% to 54% (mean 29 +/- 12%). Twenty-two of 24 jets were eccentric. Simple linear regression analysis between maximal color jet areas and peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions showed correlation, with r = 0.68 (SEE 0.64 cm2), r = 0.63 (SEE 0.67 cm2), r = 0.63 (SEE 0.67 cm2) and r = 0.58 (SEE 0.71 cm2), respectively. Univariate regression comparing regurgitant jet area with cardiac output, stroke volume, systolic left ventricular pressure, pressure gradient, left ventricular/left atrial pressure gradient, left atrial mean pressure, left atrial v wave pressure, systemic vascular resistance and maximal jet velocity showed poor correlation (0.08 < r < 0.53, SEE > 0.76 cm2). CONCLUSIONS: This study demonstrates that color Doppler jet area has limited use for evaluating the severity of mitral regurgitation with eccentric jets.     

Left atrial filling volume can be used to reliably estimate the regurgitant volume in mitral regurgitation

The gene coding for the immunity protein (mceB) and the structural gene of microcin E492 (mceA), a low-molecular-weight channel-forming bacteriocin produced by a strain of Klebsiella pneumoniae, have been characterized. The microcin gene codes for a precursor protein of either 99 or 103 amino acids. Protein sequencing of the N-terminal region of microcin E492 unequivocally identified this gene as the microcin structural gene and indicated that this microcin is synthesized as a precursor protein that is cleaved at either amino acid 15 or 19, at a site resembling the double-glycine motif. The gene encoding the 95-amino-acid immunity protein (mceB) was identified by cloning the DNA segment that encodes only this polypeptide into an expression vector and demonstrating the acquisition of immunity to microcin E492. As expected, the immunity protein was found to be associated with the inner membrane. Analysis of the DNA sequence indicates that these genes belong to the same family as microcin 24, and they do not share structural motifs with any other known channel-forming bacteriocin. The organization of the microcin- and immunity protein-encoding genes suggests that they are coordinately expressed.     

Reproducibility of color Doppler flow quantification of aortic regurgitation

The preferred method for quantification of aortic regurgitation severity with color Doppler echocardiography is the assessment of the ratio of jet diameter to left ventricular outflow tract diameter and jet area to left ventricular outflow tract area. However, the reproducibility of these measurements is not known and may limit its clinical application. This study was performed to identify sources of variability and reproducibility of the echocardiographic data. We examined 62 color Doppler echocardiographic examinations of patients showing isolated aortic regurgitation after human tissue valve implantation. The mean differences with standard deviations between paired measurements were calculated. The interobserver, intraobserver, and interframe variability showed a close agreement for the jet diameter and left ventricular outflow tract diameter measurements. The agreement for jet area and left ventricular outflow tract area measurements showed a small bias, but a large variance. The reproducibility of jet-left ventricular outflow tract diameter is better than the jet-left ventricular outflow tract area measurement and is more accurate to assess the severity of aortic regurgitation from color Doppler images.     

Application of color Doppler flow mapping to calculate orifice area of St Jude mitral valve

BACKGROUND: The effective orifice area (EOA) of a prosthetic valve is superior to transvalvular gradients as a measure of valve function, but measurement of mitral prosthesis EOA has not been reliable. METHODS AND RESULTS: In vitro flow across St Jude valves was calculated by hemispheric proximal isovelocity surface area (PISA) and segment-of-spheroid (SOS) methods. For steady and pulsatile conditions, PISA and SOS flows correlated with true flow, but SOS and not PISA underestimated flow. These principles were then used intraoperatively to calculate cardiac output and EOA of newly implanted St Jude mitral valves in 36 patients. Cardiac output by PISA agreed closely with thermodilution (r=0.91, Delta=-0.05+/-0.55 L/min), but SOS underestimated it (r=0.82, Delta=-1.33+/-0.73 L/min). Doppler EOAs correlated with Gorlin equation estimates (r=0.75 for PISA and r=0.68 for SOS, P<0.001) but were smaller than corresponding in vitro EOA estimates. CONCLUSIONS: Proximal flow convergence methods can calculate forward flow and estimate EOA of St Jude mitral valves, which may improve noninvasive assessment of prosthetic mitral valve obstruction.     

Overestimation of severity of ischemic/functional mitral regurgitation by color Doppler jet area

Color Doppler jet analysis is widely used to characterize the degree of mitral regurgitation (MR), but the validity of this approach in patients with ischemic or functional MR has not been established. It was hypothesized that color Doppler jet area overestimates the magnitude of MR of ischemic or functional origin. The severity of isolated MR in 170 patients was measured by using Doppler/echocardiography. Group 1 (n = 58) included patients with ischemic or functional MR, and group 2 (n = 112) included those with organic MR. The regurgitant jet area and 2 methods of quantitation (quantitative Doppler and quantitative 2-dimensional echocardiography) were measured simultaneously. In group 1, color jet area was larger (10.6 +/- 5.3 vs 8.2 +/- 5.3 cm2, p = 0.004) but corresponded to a smaller regurgitant volume and regurgitant fraction by quantitative Doppler (28 +/- 14 vs 55 +/- 46 ml, p = 0.0006, and 31 +/- 12% vs 38 +/- 20%, p = 0.02, respectively) and by quantitative 2-dimensional echocardiography (22 +/- 11 vs 49 +/- 40 ml, p < 0.0001, and 27 +/- 12% vs 36 +/- 20%, p = 0.005, respectively). Enlargement of the left-sided chambers was more marked in group 1. In ischemic/functional MR, the diagnosis of severe regurgitation by color Doppler (jet area > 8 cm2) was confirmed by quantitative methods (regurgitant fraction > or = 50%) in only 6% to 11% of patients, whereas it was confirmed in 60% to 73% of patients with organic MR (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Three-dimensional echocardiographic planimetry of maximal regurgitant orifice area in myxomatous mitral regurgitation: intraoperative comparison with proximal flow convergence

The purpose of this study was to evaluate the usefulness of multishot echo-planar imaging in detecting liver tumors in comparison with respiratory triggered T2-weighted fast-spin-echo (FSE) imaging. Thirty-two patients with 70 focal liver lesions were imaged using a 1.5-T high speed MR imager. Eight-shot echo-planar images covering the whole liver were acquired during a single breath-hold period. FSE images were acquired with respiratory triggering in approximately 4 minutes. Lesion detectability and image quality of the two pulse sequences were analyzed qualitatively. Quantitative analysis was performed by means of signal-to-noise and tumor-liver contrast-to-noise analysis. Lesion detectability was comparable in both solid (86.3% vs 90.2%: .3 < P < .5) and nonsolid lesions (89.5% vs 100%: .3 < P < .5) between echo-planar and FSE images. Echo-planar imaging provided significantly reduced image artifact, better lesion conspicuity, and anatomic detail compared with FSE imaging. The signal-to-noise and contrast-to-noise ratios of echo-planar images were significantly higher than those of FSE images. Breath-hold eight-shot echo-planar imaging can be an alternative to T2-weighted FSE imaging because it can provide comparable image quality in a substantially decreased acquisition time.     

Quantification of mitral and tricuspid regurgitation by the proximal flow convergence method using two-dimensional colour Doppler and colour Doppler M-mode: influence of the mechanism of regurgitation

Tamoxifen (10 pg/ml) was infused directly into superfused striatal tissue fragments of ovariectomized rats for a 50 min period. Immediately following the termination of tamoxifen there was a significant increase in dopamine output compared with non-infused controls. No such significant increase was observed with use of a 100 pg/ml tamoxifen dose. Although dopamine output was again increased upon termination of a 2 h infusion of tamoxifen, these levels failed to differ significantly from that of non-infused controls. Similarly, a shorter 10 min duration infusion of tamoxifen failed to alter dopamine output. Finally, we examined whether the tamoxifen-induced, post-infusion increase in dopamine output, as observed following a 50 min infusion of 10 pg/ml, involved a calcium dependent process. To achieve this goal, superfusions were performed with Calcium/Tamoxifen, No Calcium/Tamoxifen, No Calcium/No Tamoxifen and Calcium/No Tamoxifen. A significant increase in dopamine output post-tamoxifen infusion was obtained for the Calcium/Tamoxifen condition compared with the remaining three groups which failed to differ from one another. Taken together these results show that tamoxifen can alter dopamine output through direct, non-genomic effects upon striatal neurons. Responses to this anti-estrogen are intriguing since they are apparent following removal, but not during tamoxifen infusion and represent a calcium-dependent process. These data suggest that tamoxifen may represent an important modulator of nigrostriatal dopaminergic function.     

Mechanism of dynamic regurgitant orifice area variation in functional mitral regurgitation: physiologic insights from the proximal flow convergence technique

OBJECTIVES: We used the Doppler proximal flow convergence technique as a physiologic tool to explore the effects of the time courses of mitral annular area and transmitral pressure on dynamic changes in regurgitant orifice area. BACKGROUND: In functional mitral regurgitation (MR), regurgitant flow rate and orifice area display a unique pattern, with peaks in early and late systole and a midsystolic decrease. Phasic changes in both mitral annular area and the transmitral pressure acting to close the leaflets, which equals left ventricular-left atrial pressure, have been proposed to explain this dynamic pattern. METHODS: In 30 patients with functional MR, regurgitant orifice area was obtained as flow (from M-mode proximal flow convergence traces) divided by orifice velocity (v) from the continuous wave Doppler trace of MR, transmitral pressure as 4v(2), and mitral annular area from two apical diameters. RESULTS: All patients had midsystolic decreases in regurgitant orifice area that mirrored increases in transmitral pressure, while mitral annular area changed more gradually. By stepwise multiple regression analysis, both mitral annular area and transmitral pressure significantly affected regurgitant orifice area; however, transmitral pressure made a stronger contribution (r2 = 0.441) than mitral annular area (added r2 = 0.008). Similarly, the rate of change of regurgitant orifice area more strongly related to that of transmitral pressure (r2 = 0.638) than to that of mitral annular area (added r2 = 0.003). A similar regurgitant orifice area time course was observed in four patients with fixed mitral annuli due to Carpentier ring insertion. CONCLUSIONS: In summary, the time course and rate of change of regurgitant orifice area in patients with functional MR are predominantly determined by dynamic changes in the transmitral pressure acting to close the valve. Thus, although mitral annular area helps determine the potential for MR, transmitral pressure appears important in driving the leaflets toward closure, and would be of value to consider in interventions aimed at reducing the severity of MR.     

Transesophageal Doppler echocardiography assessment of mitral valve insufficiency: Comparison of jet area, pulmonary venous flow profile, proximal jet diameter, maximal regurgitation flow rate and regurgitation orifice area with angiography

In transesophageal echocardiography several methods have been used to grade mitral regurgitation. For a direct comparison of these techniques, 36 patients (60 +/- 13 years) with native mitral regurgitation underwent multiplane transesophageal echocardiography and angiography within 5 days. We compared the following measurements: 1) The maximal color jet area of mitral regurgitation, 2) the ratio of maximal systolic to diastolic pulmonary venous flow velocity in the left upper pulmonary vein, 3) the proximal jet width of mitral regurgitation, 4) the maximal regurgitant flow rate Qmax, measured by the proximal convergence method, 5) the regurgitant office area Areg, calculated by dividing Qmax by maximal regurgitant velocity obtained by continuous wave Doppler. RESULTS: The correlation between color jet area (r = 0.4; p < 0.05) or pulmonary venous flow (r = -0.3; p = n.s.) with angiographic severity of mitral regurgitation is low. The sensitivity of the retrospective best cut-off values is 69% (color jet area) and 83% (pulmonary venous flow). Using retrospective best cut-off values all patients with mitral regurgitation Sellers grade III and IV are correctly identified by a proximal jet width > or = 0.7 cm, Qmax > or = 300 ml/s or a Areg > or = 0.5 cm2 (sensitivity and specificity of 83-100%). Spearman's rank coefficient demonstrated a high correlation (r = 0.75-0.77; p < 0.001) between proximal jet width, Qmax and Areg and with angiographic severity. CONCLUSION: Multiplane transesophageal echocardiographic grading of mitral regurgitation by proximal jet width or proximal convergence zone shows comparably good results and is clearly superior to grading by color jet area or pulmonary venous flow, if adequate image quality is achieved.     

Color flow imaging compared with quantitative Doppler assessment of severity of mitral regurgitation: influence of eccentricity of jet and mechanism of regurgitation

OBJECTIVES: To determine the influence of jet eccentricity and mechanism of mitral regurgitation, we examined 1) the relation between jet extent and severity of mitral regurgitation, and 2) the use of Doppler color flow imaging for quantitation of mitral regurgitation. BACKGROUND: Doppler color flow imaging is widely used to assess mitral regurgitation. However, whether, how and in which subgroups it can quantify regurgitation remain controversial. METHODS: In 80 patients with mitral regurgitation, results of color flow Doppler studies obtained in two orthogonal apical views were prospectively compared with quantitative Doppler measurement of the regurgitant volume and the regurgitant fraction. Comparisons were made according to the eccentricity of the jet (group 1 eccentric jets, n = 29; group 2 central jets, n = 51); group 2 was subdivided according to the mechanism of mitral regurgitation (group 2a organic, n = 27; group 2b ischemic or functional, n = 24). RESULTS: Globally, weak correlations were found between regurgitant volume and jet area (r = 0.57) and regurgitant fraction and jet area/left atrial area ratio (r = 0.65). Groups 1 and 2 showed a correlation between regurgitant volume and jet area (r = 0.68 and r = 0.65, respectively, p < 0.0001), but the slope was steeper in group 2 than in group 1 (0.22 vs. 0.06, p < 0.0001). The same jet area corresponded to more severe regurgitation in group 1 than in group 2 (jet > or = 8 cm2, regurgitant volume 113 +/- 55 vs. 43 +/- 21 ml, p < 0.0001). Similarly, for comparable regurgitant volumes (24 +/- 22 vs. 29 +/- 11 ml, p = NS), group 2a had a smaller jet area than did group 2b (5.3 +/- 6 vs. 9.6 +/- 6 cm2, p < 0.02). Quantitation of regurgitation by Doppler color flow imaging was unreliable in group 1; in group 2b, the regression line between regurgitant fraction and jet area/left atrial area ratio was close to the identity line. CONCLUSIONS: Mitral regurgitant jet eccentricity and mechanism influence jet extent. The same regurgitant volume produces smaller jet areas for eccentric compared with central jets and for central organic compared with ischemic or functional regurgitation. Quantitation of regurgitation using Doppler color flow imaging is possible in ischemic or functional regurgitation but inappropriate in eccentric jets, where quantitative Doppler study should be recommended.     

Afterload reduction therapy with nitroprusside in severe aortic regurgitation: improved cardiac performance and reduced regurgitant volume

To assess the hemodynamic effects of afterload reduction in severe aortic regurgitation, nitroprusside was infused at cardiac catheterization in 12 patients with aortic regurgitation. Cardiac hemodynamics, angiographic variables and regurgitant volumes were quantified during control periods, and nitroprusside was infused to reduce systemic systolic pressure to 110 to 125 mm Hg. The following were reduced by the drug: systolic arterial pressure (from 154 +/- 6.4 to 115 +/- 2.3 mm Hg, P less than 0.001); left ventricular end-diastolic pressure (from 23 +/- 2.2 to 11 +/- 1.0 mm Hg, P less than 0.001); systemic vascular resistance (from 1,782 +/- 133 to 1,148 +/- 94 dynes sec cm-5, P less than 0.001); left ventricular end-diastolic volume (from 242 +/- 25 to 196 +/- 19 ml, P less than 0.001); aortic regurgitant fraction (from 0.53 +/- 0.05 to 0.44 +/- 0.06, P less than 0.01); and aortic regurgitant minute volume (from 5.5 +/- 0.10 to 4.3 +/- 0.09 liters/min, P less than 0.01). Effective cardiac index increased (from 2.49 +/- 0.19 to 3.10 +/- 0.24 liters/min per m2, P less than 0.01), and left ventricular ejection fraction rose (from 0.55 +/- 0.03 to 0.61 +/- 0.03, P less than 0.005). These data indicate that afterload reduction with nitroprusside in severe aortic regurgitation improves cardiac performance, greatly decreases left ventricular preload and reduces aortic regurgitant volume. Thus, nitroprusside therapy has special value in severe aortic regurgitation that is of particular benefit in critical clinical conditions.     

Noninvasive assessment of significant left anterior descending coronary artery stenosis by coronary flow velocity reserve with transthoracic color Doppler echocardiography

BACKGROUND: Coronary flow reserve has been considered an important diagnostic index of the functional significance of coronary artery stenosis. With Doppler technique, it has been assessed as the ratio of hyperemic to basal coronary flow velocity (coronary flow velocity reserve [CFVR]) by invasive or semiinvasive methods with a Doppler catheter, a Doppler guide wire, and a transesophageal Doppler echocardiographic probe. Recent technological advancement in transthoracic Doppler echocardiography (TTDE) provides measurement of coronary flow velocity in the distal portion of the left anterior descending coronary artery (LAD) and may be useful in the noninvasive CFVR measurement. The purpose of this study was to evaluate the value of CFVR determined by TTDE for the assessment of significant LAD stenosis. METHODS AND RESULTS: We studied 36 patients who underwent coronary angiography for the assessment of coronary artery disease. The study population consisted of 12 patients with significant LAD stenosis (group A) and 24 patients without significant LAD stenosis (group B). With TTDE, coronary flow velocities in the distal LAD were recorded at rest and during hyperemia induced by intravenous infusion of adenosine (0.14 mg x kg(-1) x min(-1)) under the guidance of color Doppler flow mapping. Adequate spectral Doppler recordings of coronary flow in the distal LAD for the assessment of CFVR were obtained in 34 of 36 study patients (94%). The peak and mean diastolic coronary flow velocities at baseline did not differ between groups A and B (23.6+/-10.3 versus 22.9+/-6.6 cm/s and 16.4+/-8.6 versus 14.5+/-4.0 cm/s, respectively). However, the peak and mean coronary flow velocities during hyperemia in group A were significantly smaller than those in group B (35.6+/-16.3 versus 54.2+/-16.3 cm/s and 24.7+/-13.1 versus 37.9+/-13.0 cm/s, respectively; P<.01). There were significant differences in CFVR obtained from peak and mean diastolic velocity between groups A and B (1.5+/-0.2 versus 2.4+/-0.4 and 1.5+/-0.2 versus 2.6+/-0.4, respectively; P<.001). A CFVR from peak diastolic velocity <2.0 had a sensitivity of 92% and a specificity of 82% for the presence of significant LAD stenosis. A CFVR from mean diastolic velocity <2.0 had a sensitivity of 92% and a specificity of 86% for the presence of significant LAD stenosis. CONCLUSIONS: CFVR determined by TTDE is useful in the noninvasive assessment of significant stenotic lesion in the LAD.     

Accuracy of color doppler velocity in the flow field proximal to a regurgitant orifice: implications for color doppler quantitation of valvular incompetence

Color Doppler is routinely used in estimates of valvular regurgitation. Velocity and subsequently flow measurements are made at about 7-10 cm from the ultrasonic transducer. Error in velocity measurement may occur due to spatial broadening of the color Doppler beam in the axial, azimuthal and lateral directions. Error in velocity may also occur due to wall filters since the filtering process is not uniform throughout the velocity range indicated by the color bar. An attempt to estimate this error was made using an in vitro orifice model, a numerical finite element model (FEM), and information from the manufacturer. We found that the acoustic beam spatial expansion, wall filter sensitivity and Nyquist limit (NYL) have to be considered simultaneously to account for errors. The combined spatial expansion and wall filter effect on velocity was estimated as a weighted average over the sample volume. The error distributions are not universal but depend on orifice size and flow. For a 3-mm orifice and 100 cm s NYL the overall effect was overestimation of low velocities and significant underestimation of high velocities due to the high velocity gradients inside the sample volume. For the 5- and the 10-mm orifice the effect was less accentuated. Based on this overall error distribution, a correction was incorporated on color Doppler obtained data. The incorporated correction yielded better agreement with numerical velocity data. This correction is important in the application of the proximal isovelocity surface area (PISA) technique and the evaluation of regurgitant flowrates.     

Comparison of vena contracta width by multiplane transesophageal echocardiography with quantitative Doppler assessment of mitral regurgitation

OBJECTIVE: To compare prostacyclin with an analogue, iloprost, in treatment of severe pulmonary hypertension. PATIENTS: Eight patients with severe pulmonary hypertension: primary in five, thromboembolic pulmonary hypertension in three. METHODS: All patients underwent right heart catheterisation. Mean (SEM) right atrial pressure was 9.9 (2.2) mm Hg, mean pulmonary artery pressure 67.4 (3.0) mm Hg, cardiac index 1.75 (0.13) l/min/m2 and mixed venous oxygen saturation 59.1(3.1)%. Continuous intravenous epoprostenol (prostacyclin, PGI2) or iloprost was given for phase I (three to six weeks); the patients were then crossed over to receive the alternate drug in an equivalent phase II. MAIN OUTCOME MEASURES: Exercise tolerance was measured at baseline and at the end of phase I and II with a 12 minute walk; distance covered, rest period, percentage drop in arterial oxygen saturation (delta Sao2%) and percentage rise in heart rate (delta HR%). RESULTS: Walking distance covered rose from (mean (SEM)) 407.5 (73) to 591 (46) m with PGI2 (p = 0.004) and to 602.5 (60) m while on iloprost (p = 0.008). Rest period decreased from 192 (73) seconds at baseline to 16 (16) seconds with PGI2 (p = 0.01) and to 58 (34) seconds with iloprost (p = 0.008). Delta HR% was 37.5(6)% at baseline, 35(3)% on PGI2, and 24(6)% on iloprost (p = 0.04). CONCLUSIONS: Both intravenous PGI2 and iloprost caused significant improvement in exercise tolerance. Iloprost offers an alternative to PGI2 treatment of severe pulmonary hypertension.     

Clinical usefulness of the effective regurgitant orifice area determined by transesophageal echocardiography in patients with eccentric aortic regurgitation

BACKGROUND AND AIMS OF THE STUDY: The aortic regurgitant jet is frequently eccentric, and Doppler color flow mapping techniques of the distal jet is influenced by this eccentricity. The aim of the present study was to determine whether the effective regurgitant orifice area (EROA), determined by the proximal isovelocity surface area (PISA) method using multiplane transesophageal echocardiography (m-TEE), could be used to evaluate the severity of aortic regurgitation (AR) in patients with an eccentric jet. METHODS: Forty-eight patients with eccentric AR were studied. Values of EROA determined by the PISA method were compared with results from cross-sectional area (CSA), vena contracta (VC) width, aortic angiography, and regurgitant fraction. RESULTS: Values of EROA correlated well with results from CSA (r = 0.73, p < 0.001), VC (r = 0.74, p < 0.001), angiographic grade (rs = 0.90 p < 0.001), and regurgitant fraction (r = 0.84, p < 0.001) in patients with eccentric aortic regurgitation. Values of EROA > 0.27 cm2 were always associated with a regurgitant fraction > 0.4, while EROA values < 0.27 cm2 were always associated with a regurgitant fraction < 0.4. CONCLUSIONS: We conclude that, in patients with an eccentric jet, measurement of EROA values by the PISA method using m-TEE is a reliable method of assessing the severity of AR.