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1.
J Am Coll Cardiol ; 26(4): 1047-53, 1995 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7560598

RESUMEN

OBJECTIVES: This study investigated the accuracy of mitral inflow quantification using biplane transesophageal echocardiography. BACKGROUND: Mitral stroke volume can be reliably quantified by transthoracic Doppler echocardiography, but previous studies involving monoplane transesophageal echocardiography have yielded mixed results. METHODS: Thirty patients without mitral regurgitation were prospectively examined immediately before cardiovascular surgery. Mitral annulus diameter was measured in the transverse (d1) and longitudinal views (d2) by biplane transesophageal echocardiography. Assuming an elliptic shape, the annular area was calculated as pi d1d2/4; area was also calculated from single-plane data assuming a circular annular shape as pi d2/4. The time-velocity integral of mitral annular Doppler velocity was then multiplied by annular area to yield stroke volume. These data were compared with simultaneous thermodilution measurements by linear regression. RESULTS: Good correlations were observed between thermodilution (x) and Doppler (y) measurements of stroke volume (SV) (r = 0.86, p < 0.01, delta SV [y-x] = 2.64 +/- 9.86 ml for single four-chamber view; r = 0.77, p < 0.01, delta SV = 1.82 +/- 12.59 ml for two-chamber view; r = 0.94, p < 0.001, delta SV = 1.78 +/- 5.90 ml for biplane measurements) with similar data for cardiac output (r = 0.82, r = 0.74 and r = 0.92, respectively). The biplane measurements were most accurate and had less variability in individual patients (p < 0.05). This finding was supported by a numerical model that demonstrated (for an ellipse of eccentricity 1.5:1) that even maximal misalignment of biplane diameters yielded only 8% area overestimation, whereas single-plane calculations assuming a circular shape produced a variation in area of 225%. CONCLUSIONS: This study validates the accuracy of measurements of mitral inflow using biplane transesophageal echocardiography with potential application for quantification of valvular regurgitation in the operating room. The results are further generalizable, indicating that orthogonal biplane measurements are both necessary and sufficient to ensure accuracy in area calculation for any elliptic structure.


Asunto(s)
Gasto Cardíaco , Ecocardiografía Transesofágica/métodos , Válvula Mitral/diagnóstico por imagen , Volumen Sistólico , Adulto , Anciano , Procedimientos Quirúrgicos Cardíacos , Cateterismo de Swan-Ganz , Ecocardiografía Doppler/métodos , Femenino , Humanos , Cuidados Intraoperatorios , Modelos Lineales , Masculino , Persona de Mediana Edad , Modelos Cardiovasculares , Modelos Teóricos , Monitoreo Intraoperatorio , Estudios Prospectivos , Reproducibilidad de los Resultados , Termodilución
2.
J Am Coll Cardiol ; 27(3): 706-13, 1996 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-8606286

RESUMEN

OBJECTIVES: This study sought to elevate the effect of proximal flow constraint induced by the left ventricular wall on the accuracy of calculated flow rates and to assess a possible correction factor to adjust the proximal convergence angle. We further defined under which hydrodynamic and geometric conditions it is necessary to apply the corrected convergence angle. BACKGROUND: The proximal flow convergence method has been proposed as a new approach to quantify valvular regurgitation. However, significant overestimation of the calculated regurgitant flow rate has been reported, particularly in patients with mitral valve prolapse and severe mitral regurgitation. METHODS: We used an in vitro flow model and induced various degrees of proximal flow constraint. The accuracy of the proposed convergence angle formula, alpha = tau + 2 tan-1 d/r (d = wall distance; r = isovelocity radius) was tested in vitro and in a three-dimensional numerical simulation. RESULTS: With a constraining wall near the orifice, overstimulation of regurgitant flow rates was noted and was most significant with the constraining wall positioned closest to the orifice (calculated flow rate [Qc]/true flow rate [Qo] = 1.85 +/- 0.55 [mean +/- SD]). These findings were similar to the results of the numerical simulation. Applying the correction factor nearly completely eliminated the overestimation of the calculated flow rates (cQc), with cQc/Qo = 1.13 +/- 0.25. CONCLUSIONS: In the presence of a constraining wall, significant overestimation of calculated flow rates is observed when hemispheric symmetry of the flow field is assumed. In this situation, it is necessary to apply the corrected convergence angle formula to improve the accuracy of the proximal flow convergence method.


Asunto(s)
Ecocardiografía Doppler en Color , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Insuficiencia de la Válvula Mitral/fisiopatología , Sesgo , Velocidad del Flujo Sanguíneo , Factores de Confusión Epidemiológicos , Pruebas de Función Cardíaca , Humanos , Modelos Cardiovasculares , Análisis Numérico Asistido por Computador , Reproducibilidad de los Resultados
3.
J Am Coll Cardiol ; 22(2): 535-41, 1993 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8335826

RESUMEN

OBJECTIVES: The purpose of the study was to develop and validate an automated method for calculating regurgitant flow rate using color Doppler echocardiography. BACKGROUND: The proximal flow convergence method is a promising approach to quantitate valvular regurgitation noninvasively because it allows one to calculate regurgitant flow rate and regurgitant orifice area; however, defining the location of the regurgitant orifice is often difficult and can lead to significant error in the calculated flow rates. To overcome this problem we developed an automated algorithm to locate the orifice and calculate flow rate based on the digital Doppler velocity map. METHODS: This algorithm compares the observed velocities with the anticipated relative velocities, cos psi/2 pi r2. The orifice is localized as the point with maximal correlation between predicted and observed velocity, whereas flow rate is specified as the slope of the regression line. We validated this algorithm in an in vitro model for flow through circular orifices with planar surroundings and a porcine bioprosthesis. RESULTS: For flow through circular orifices, flow rates calculated on individual Doppler maps and on an average of eight velocity maps showed excellent agreement with true flow, with r = 0.977 and delta Q = -3.7 +/- 15.8 cm3/s and r = 0.991 and delta Q = -4.3 +/- 8.5 cm3/s, respectively. Calculated flow rates through the bioprosthesis correlated well but underestimated true flow, with r = 0.97, delta Q = -10.9 +/- 12.5 cm3/s, suggesting flow convergence over an angle > 2 pi. This systematic underestimation was corrected by assuming an effective convergence angle of 212 degrees. CONCLUSIONS: This algorithm accurately locates the regurgitant orifice and calculates regurgitant flow rate for circular orifices with planar surroundings. Automated analysis of the proximal flow field is also applicable to more physiologic surfaces surrounding the regurgitant orifice; however, the convergence angle should be adjusted. This automated algorithm should make quantification of regurgitant flow rate and regurgitant orifice area more reproducible and readily available in clinical cardiology practice.


Asunto(s)
Algoritmos , Velocidad del Flujo Sanguíneo , Enfermedades de las Válvulas Cardíacas/fisiopatología , Válvulas Cardíacas/fisiología , Simulación por Computador , Ecocardiografía Doppler/métodos , Válvulas Cardíacas/fisiopatología , Humanos , Modelos Cardiovasculares , Procesamiento de Señales Asistido por Computador
4.
J Am Coll Cardiol ; 36(6): 1942-9, 2000 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-11092668

RESUMEN

OBJECTIVES: We hypothesized that color M-mode (CMM) images could be used to solve the Euler equation, yielding regional pressure gradients along the scanline, which could then be integrated to yield the unsteady Bernoulli equation and estimate noninvasively both the convective and inertial components of the transmitral pressure difference. BACKGROUND: Pulsed and continuous wave Doppler velocity measurements are routinely used clinically to assess severity of stenotic and regurgitant valves. However, only the convective component of the pressure gradient is measured, thereby neglecting the contribution of inertial forces, which may be significant, particularly for nonstenotic valves. Color M-mode provides a spatiotemporal representation of flow across the mitral valve. METHODS: In eight patients undergoing coronary artery bypass grafting, high-fidelity left atrial and ventricular pressure measurements were obtained synchronously with transmitral CMM digital recordings. The instantaneous diastolic transmitral pressure difference was computed from the M-mode spatiotemporal velocity distribution using the unsteady flow form of the Bernoulli equation and was compared to the catheter measurements. RESULTS: From 56 beats in 16 hemodynamic stages, inclusion of the inertial term ([deltapI]max = 1.78+/-1.30 mm Hg) in the noninvasive pressure difference calculation significantly increased the temporal correlation with catheter-based measurement (r = 0.35+/-0.24 vs. 0.81+/-0.15, p< 0.0001). It also allowed an accurate approximation of the peak pressure difference ([deltapc+I]max = 0.95 [delta(p)cathh]max + 0.24, r = 0.96, p<0.001, error = 0.08+/-0.54 mm Hg). CONCLUSIONS: Inertial forces are significant components of the maximal pressure drop across the normal mitral valve. These can be accurately estimated noninvasively using CMM recordings of transmitral flow, which should improve the understanding of diastolic filling and function of the heart.


Asunto(s)
Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Insuficiencia de la Válvula Mitral/fisiopatología , Válvula Mitral/fisiología , Ultrasonografía Doppler en Color , Función Ventricular Izquierda , Presión Ventricular , Anciano , Femenino , Hemodinámica , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Análisis de Regresión
5.
J Am Coll Cardiol ; 30(5): 1288-94, 1997 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-9350929

RESUMEN

OBJECTIVES: We studied the effects of left ventricular (LV) unloading by an implantable ventricular assist device on LV diastolic filling. BACKGROUND: Although many investigators have reported reliable systemic and peripheral circulatory support with implantable LV assist devices, little is known about their effect on cardiac performance. METHODS: Peak velocities of early diastolic filling, late diastolic filling, late to early filling ratio, deceleration time of early filling, diastolic filling period and atrial filling fraction were measured by intraoperative transesophageal Doppler echocardiography before and after insertion of an LV assist device in eight patients. A numerical model was developed to simulate this situation. RESULTS: Before device insertion, all patients showed either a restrictive or a monophasic transmitral flow pattern. After device insertion, transmitral flow showed rapid beat to beat variation in each patient, from abnormal relaxation to restrictive patterns. However, when the average values obtained from 10 consecutive beats were considered, overall filling was significantly normalized from baseline, with early filling velocity falling from 87 +/- 31 to 64 +/- 26 cm/s (p < 0.01) and late filling velocity rising from 8 +/- 11 to 32 +/- 23 cm/s (p < 0.05), resulting in an increase in the late to early filling ratio from 0.13 +/- 0.18 to 0.59 +/- 0.38 (p < 0.01) and a rise in the atrial filling fraction from 8 +/- 10% to 26 +/- 17% (p < 0.01). The deceleration time (from 112 +/- 40 to 160 +/- 44 ms, p < 0.05) and the filling period corrected by the RR interval (from 39 +/- 8% to 54 +/- 10%, p < 0.005) were also significantly prolonged. In the computer model, asynchronous LV assistance produced significant beat to beat variation in filling indexes, but overall a normalization of deceleration time as well as other variables. CONCLUSIONS: With LV assistance, transmitral flow showed rapidly varying patterns beat by beat in each patient, but overall diastolic filling tended to normalize with an increase of atrial contribution to the filling. Because of the variable nature of the transmitral flow pattern with the assist device, the timing of the device cycle must be considered when inferring diastolic function from transmitral flow pattern.


Asunto(s)
Insuficiencia Cardíaca/terapia , Corazón Auxiliar , Función Ventricular Izquierda , Adulto , Cardiomiopatía Dilatada/complicaciones , Vasos Coronarios/fisiología , Ecocardiografía Doppler , Ecocardiografía Transesofágica , Femenino , Insuficiencia Cardíaca/etiología , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Isquemia Miocárdica/complicaciones , Flujo Sanguíneo Regional
6.
J Am Coll Cardiol ; 34(3): 795-801, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10483962

RESUMEN

OBJECTIVES: The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. BACKGROUND: Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in LA volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (LA dP/dt(max)). METHODS: Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous LA pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with a micromanometer catheter, and LA dP/dt(max) during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive a multilinear regression equation to estimate LA dP/dt(max) from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. A previously validated numeric model was used to confirm these results. RESULTS: In the study group, LA dP/dt(max) showed a linear relation with LA pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with LA dP/dt(max) (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate LA dP/dt(max) with an r2 > 0.30. By stepwise and multiple linear regression analysis, LA dP/dt(max) was best described as follows: LA dP/dt(max) = 0.1 M-AC +/- 1.8 P-V - 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured LA dP/dt(max) correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across a wide range of atrial elastance, ventricular relaxation and systolic function, with LA dP/dt(max) predicted by the above equation with r = 0.94. CONCLUSIONS: A combination of transmitral and pulmonary venous flow parameters can provide a hemodynamic assessment of LA systolic function.


Asunto(s)
Función del Atrio Izquierdo/fisiología , Válvula Mitral/fisiología , Venas Pulmonares/fisiología , Adulto , Anciano , Procedimientos Quirúrgicos Cardíacos/estadística & datos numéricos , Ecocardiografía Doppler/métodos , Ecocardiografía Doppler/estadística & datos numéricos , Femenino , Hemodinámica , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Válvula Mitral/diagnóstico por imagen , Modelos Cardiovasculares , Monitoreo Intraoperatorio/estadística & datos numéricos , Venas Pulmonares/diagnóstico por imagen , Sístole/fisiología
7.
Am J Cardiol ; 72(17): 1305-9, 1993 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-8256709

RESUMEN

The visual assessment of jet area has become the most common method used in daily clinic practice to evaluate valvular regurgitation. Despite the high prevalence of tricuspid regurgitation, however, few studies have systematically compared TR jet areas with a quantitative standard. To evaluate this, 40 patients in sinus rhythm with tricuspid regurgitation were analyzed: 16 with centrally directed free jets and 24 with impinging wall jets. The size of the maximal planimetered color jet area (cm2) was compared with parameters derived using the pulsed Doppler 2-dimensional echocardiographic method: regurgitant fraction and the flow convergence method (peak flow rate, effective regurgitant orifice area and momentum). Mean tricuspid regurgitant fraction averaged 33 +/- 15%, peak flow rate 76 +/- 54 cm3/s, effective regurgitant orifice area 27 +/- 21 mm2 and momentum 21,717 +/- 15,014 cm4/s2. An average of 4-chamber, and long- and short-axis areas in free jets correlated well with regurgitant fraction (r = 0.81, p < 0.001), better with peak flow rate (r = 0.94, p < 0.001), effective regurgitant orifice (r = 0.92, p < 0.001) and momentum (r = 0.94, p < 0.001). The correlation was worse, but still significant, in wall jets. For the same peak flow rate, wall jets were 75% of the size of a corresponding free jet. Jet area measurement is a good semiquantitative tool to measure tricuspid regurgitation in free jets, which correlates well with regurgitant fraction and better with new parameters available from analysis of the proximal acceleration field. In patients with eccentrically directed wall jets the correlation with planimetered jet area was worse, but still significant.


Asunto(s)
Insuficiencia de la Válvula Tricúspide/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Factores de Confusión Epidemiológicos , Ecocardiografía Doppler , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Insuficiencia de la Válvula Tricúspide/diagnóstico por imagen
8.
Am J Cardiol ; 87(1): 66-70, 2001 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-11137836

RESUMEN

Semiquantitative grading of mitral regurgitation (MR) by transesophageal echocardiography (TEE) is widely used for clinical decision making. However, the relation between semiquantitative grading by biplane or multiplane TEE and quantitative measures remains undetermined. Biplane or multiplane TEE was performed in 113 patients in the operating room. MR severity was graded from 1 to 4+ by Doppler color flow mapping. MR was quantified using the thermodilution-Doppler method as mitral regurgitant stroke volume (RSV) derived from the difference between total mitral inflow measured by pulsed Doppler and forward flow measured by thermodilution. Mitral regurgitant orifice area (ROA) was calculated by RSV divided by mitral regurgitant velocity. RSV and ROA were also calculated using the proximal isovelocity surface area method. RSV and ROA significantly correlated with the semiquantitative grading either by TEE or angiogram in a nonlinear fashion, with the best fit being given by an exponential model with correlation coefficients from 0.73 to 0.87 (p <0.001). Substantially increased RSV and ROA were observed in MR grades of > or =3+. In the same grades of 3+ or 4+ MR, the largest RSV was 4 times larger than the smallest (190 to 220 vs 44 to 45 ml), and the largest ROA (1.82 to 2.0 vs 0.26 to 0.27 cm2) was sixfold larger than the smallest. Patients with 2 to 3+ MR had significantly variable RSV and ROA (range 21 to 91 ml and 0.12 to 0.65 cm2, respectively). Color flow mapping by biplane or multiplane TEE or angiography is able to categorize precisely mild (< or =2+) and severe (> or =3+) MR, but cannot accurately determine actual hemodynamic load of MR in more severe degrees of MR.


Asunto(s)
Ecocardiografía Transesofágica/métodos , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Femenino , Hemodinámica/fisiología , Humanos , Masculino , Persona de Mediana Edad , Insuficiencia de la Válvula Mitral/fisiopatología , Volumen Sistólico/fisiología , Termodilución
9.
J Am Soc Echocardiogr ; 7(5): 480-7, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7986545

RESUMEN

To investigate which factors influence visual evaluation and how accurate it is in patients with valvular insufficiency, 83 patients were studied. All were in sinus rhythm, 43 with mitral and 40 with tricuspid regurgitation. Categoric visual grading (mild, moderate, and severe) was compared with jet area method and regurgitant fraction and the factors that influenced the assigned rank were identified. With jet area method (mean of areas in three planes), the correlation with regurgitant fraction was r = 0.61 for free jets and r = 0.32 for wall jets (overall r = 0.47) in patients with mitral regurgitation, and r = 0.81 and r = 0.46 for free and wall jets, respectively, in patients with tricuspid regurgitation (overall, r = 0.65). With visual grading, the correlation was for free and wall jets, respectively, rho = 0.80 and rho = 0.74 (overall rho = 0.76) in patients with mitral regurgitation, and rho = 0.79 and rho = 0.49 for free and wall jets, respectively (overall rho = 0.62), in patients with tricuspid regurgitation. The jet area parameter found to have the most influence on visual grading was the average area in three planes divided by atrial area, with rho = 0.80 and rho = 0.51 in patients with mitral regurgitation (free and impinging jets respectively) and rho = 0.60 and rho = 0.46 in tricuspid regurgitation. We conclude that visual grading of valvular regurgitant jets correlates well with quantitative measures of valvular incompetence and better than any simple jet area method.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Ecocardiografía Doppler , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Insuficiencia de la Válvula Tricúspide/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Ecocardiografía Doppler/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Grabación en Video
10.
J Am Soc Echocardiogr ; 9(5): 606-15, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8887862

RESUMEN

To test the impact of Joint Photographic Expert Group (JPEG) compression on the quantitative data encoded in color Doppler echocardiographic images, digital images from transesophageal echocardiography and an in vitro model of proximal flow convergence were analyzed before and after JPEG compression with compression ratios (CRs) as high as 65:1. Even at the highest CRs, greater than 95% of the pixels were categorized correctly as representing structure (gray scale) and greater than 98% were categorized correctly as representing velocity (color) data. Furthermore, the velocities and flows recovered from the compressed images agreed well (r = 0.998 [velocities] and r = 0.998 [flows] for CR = 7:1, falling to r = 0.881 [velocities] and r = 0.930 [flows] at CR = 65:1; p < 0.001 for the linear trend with CR). There was similarly little shift in the location of the red-blue aliasing contour, rising from an error of 0.05 +/- 0.19 (mean +/- SD) mm at CR = 7:1 to a maximum error of 0.11 +/- 0.36 mm at CR = 44:1. Thus JPEG compression has little impact on the quantitative velocity data encoded within color Doppler echocardiograms, which should allow widespread acceptance of digital transmission and storage.


Asunto(s)
Ecocardiografía Doppler en Color , Ecocardiografía Transesofágica , Humanos , Aumento de la Imagen/métodos
11.
J Am Soc Echocardiogr ; 12(9): 736-43, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10477418

RESUMEN

Although alteration in pulmonary venous flow has been reported to relate to mitral regurgitant severity, it is also known to vary with left ventricular (LV) systolic and diastolic dysfunction. There are few data relating pulmonary venous flow to quantitative indexes of mitral regurgitation (MR). The object of this study was to assess quantitatively the accuracy of pulmonary venous flow for predicting MR severity by using transesophageal echocardiographic measurement in patients with variable LV dysfunction. This study consisted of 73 patients undergoing heart surgery with mild to severe MR. Regurgitant orifice area (ROA), regurgitant stroke volume (RSV), and regurgitant fraction (RF) were obtained by quantitative transesophageal echocardiography and proximal isovelocity surface area. Both left and right upper pulmonary venous flow velocities were recorded and their patterns classified by the ratio of systolic to diastolic velocity: normal (>/=1), blunted (<1), and systolic reversal (<0). Twenty-three percent of patients had discordant patterns between the left and right veins. When the most abnormal patterns either in the left or right vein were used for analysis, the ratio of peak systolic to diastolic flow velocity was negatively correlated with ROA (r = -0.74, P <.001), RSV (r = -0.70, P <.001), and RF (r = -0.66, P <.001) calculated by the Doppler thermodilution method; values were r = -0.70, r = -0.67, and r = -0.57, respectively (all P <.001), for indexes calculated by the proximal isovelocity surface area method. The sensitivity, specificity, and predictive values of the reversed pulmonary venous flow pattern for detecting a large ROA (>0.3 cm(2)) were 69%, 98%, and 97%, respectively. The sensitivity, specificity, and predictive values of the normal pulmonary venous flow pattern for detecting a small ROA (<0.3 cm(2)) were 60%, 96%, and 94%, respectively. However, the blunted pattern had low sensitivity (22%), specificity (61%), and predictive values (30%) for detecting ROA of greater than 0.3 cm(2) with significant overlap with the reversed and normal patterns. Among patients with the blunted pattern, the correlation between the systolic to diastolic velocity ratio was worse in those with LV dysfunction (ejection fraction <50%, r = 0.23, P >.05) than in those with normal LV function (r = -0.57, P <.05). Stepwise linear regression analysis showed that the peak systolic to diastolic velocity ratio was independently correlated with RF (P <.001) and effective stroke volume (P <.01), with a multiple correlation coefficient of 0.71 (P <.001). In conclusion, reversed pulmonary venous flow in systole is a highly specific and reliable marker of moderately severe or severe MR with an ROA greater than 0.3 cm(2), whereas the normal pattern accurately predicts mild to moderate MR. Blunted pulmonary venous flow can be seen in all grades of MR with low predictive value for severity of MR, especially in the presence of LV dysfunction. The blunted pulmonary venous flow pattern must therefore be interpreted cautiously in clinical practice as a marker for severity of MR.


Asunto(s)
Ecocardiografía Doppler , Ecocardiografía Transesofágica , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Venas Pulmonares/diagnóstico por imagen , Venas Pulmonares/fisiopatología , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Velocidad del Flujo Sanguíneo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Sístole/fisiología , Termodilución
12.
Acta Cardiol ; 56(4): 263-7, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11573835

RESUMEN

Aneurysms or pseudoaneurysms of the native coronary arteries or bypass grafts are uncommon and represent a pathology with high morbidity and mortality. We report the diagnosis of an aneurysm of a saphenous vein coronary artery bypass graft with an atypical presentation and review incidence, modes of presentation, aetiology and proposed mechanisms of formation of this and similar entities. Complications, diagnostic clues and therapeutic options are also discussed.


Asunto(s)
Aneurisma Coronario/complicaciones , Puente de Arteria Coronaria/efectos adversos , Vena Safena/fisiopatología , Aneurisma Coronario/diagnóstico por imagen , Aneurisma Coronario/terapia , Ecocardiografía Transesofágica , Electrocardiografía , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Vena Safena/diagnóstico por imagen
13.
Rev Esp Cardiol ; 47(9): 597-603, 1994 Sep.
Artículo en Español | MEDLINE | ID: mdl-7973026

RESUMEN

BACKGROUND: Quantitation of valvular regurgitation remains an important goal in cardiology. It has been described previously that using color Doppler flow mapping, measurements of apparent jet size do not correlate always closely with quantitative regurgitant indexes. Recently the proximal flow convergence method has been proposed to quantify valvular regurgitation by analysis of the converging flow field proximal to a regurgitant lesion. Assuming hemispherical convergence, peak flow rate Qp can be calculated as Qp = 2 pi r2Va, where Va is the aliasing velocity at a distance r from the orifice. For maximal accuracy, previously validated correction factors must be used to account for the flattening effect of the isovelocity contours close to the orifice and for the actual sector angle subtended by the valve leaflets (alpha) to yield a flow rate formula Qp = 2 pi r2Va (Vp/Vp-Va) (alpha/180), where Vp is the orifice velocity obtained by continuous wave Doppler. METHODS: In 45 patients (35 in sinus rhythm, 10 with atrial fibrillation) with tricuspid regurgitation, regurgitant stroke volume, regurgitant flow rate were calculated using the proximal flow convergence method and compared with values obtained by the Doppler two-dimensional echocardiographic method. RESULTS: Regurgitant stroke volumes (SV) calculated by the proximal flow convergence method correlated very closely with values obtained by the Doppler two-dimensional method with r = 0.95 (y = 0.94x + 0.99) and delta SV = -0.3 +/- 5.2 cm3. Regurgitant flow rates (Q) calculated by both methods showed a similar correlation: r = 0.96 (y = 0.97x + 45) and delta Q = 1.6 +/- 4.29 cm3/min. All correlations were slightly better for the group of patients in sinus rhythm. CONCLUSION: This study demonstrates that the proximal flow convergence method is an accurate and reproducible technique for quantifying tricuspid regurgitation. While improvements of this method are to be expected, flow calculations based on the proximal flow field show excellent results and appear appropriate for clinical use.


Asunto(s)
Ecocardiografía Doppler en Color/métodos , Insuficiencia de la Válvula Tricúspide/diagnóstico por imagen , Adulto , Anciano , Velocidad del Flujo Sanguíneo , Ecocardiografía Doppler en Color/instrumentación , Ecocardiografía Doppler en Color/estadística & datos numéricos , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Circulación Pulmonar , Reproducibilidad de los Resultados , Válvula Tricúspide/diagnóstico por imagen , Válvula Tricúspide/fisiopatología , Insuficiencia de la Válvula Tricúspide/fisiopatología
14.
Rev Esp Cardiol ; 47(3): 173-80, 1994 Mar.
Artículo en Español | MEDLINE | ID: mdl-8184168

RESUMEN

BACKGROUND: It has been shown previously that using color Doppler flow mapping, simple measurements of apparent jet size do not correlate closely with regurgitant flow rate and regurgitant fraction. Recently the proximal flow convergence method has been proposed to quantify valvular regurgitation by analysis of the converging flow field proximal to a regurgitant lesion. Flow rate Q can be calculated as Q = 2 pi r2va where va is the aliasing velocity at a distance r from the orifice. PATIENTS AND METHODS: In 54 patients (43 in sinus rhythm, 11 with atrial fibrillation) with at least mild mitral regurgitation by semi-quantitative assessment, regurgitant stroke volume, regurgitant flow rate, and regurgitant fraction were calculated using the proximal flow convergence method and compared with values obtained by the Doppler/two-dimensional echocardiographic method. RESULTS: Regurgitant stroke volumes (VL) calculated by the proximal flow convergence method correlated very closely with values obtained by the Doppler-2D method with r = 0.93 (y = 0.95x + 0.55) and delta VL = -0.3 +/- 4.0 cm3. Regurgitant flow rates (Q) calculated by both methods showed a similar correlation: r = 0.93 (y = 0.95x + 54) and delta Q = -34 +/- 284 cm3/min. The correlation for regurgitant fraction (RF) calculated by both techniques showed r = 0.89 (y = 0.98x + 0.006) and delta RF = -0.005 +/- 0.06. All correlations were slightly better for the group of patients in sinus rhythm compared with the study group in atrial fibrillation. CONCLUSION: This study demonstrates that the proximal flow convergence method is an accurate and reproducible technique to quantify mitral regurgitation. This approach is easy and less time-consuming than the Doppler-echocardiographic method. While future improvements of this method are to be expected, flow calculations based on the assumption of simple hemispheric symmetry of the proximal flow field appear suitable for clinical application at the present time.


Asunto(s)
Ecocardiografía Doppler/métodos , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Velocidad del Flujo Sanguíneo , Ecocardiografía/métodos , Ecocardiografía/estadística & datos numéricos , Ecocardiografía Doppler/estadística & datos numéricos , Estudios de Evaluación como Asunto , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/fisiopatología , Insuficiencia de la Válvula Mitral/fisiopatología , Reproducibilidad de los Resultados
19.
Am J Physiol ; 271(4 Pt 2): H1267-76, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8897917

RESUMEN

Pulsed and continuous wave Doppler velocity measurements are routinely used in clinical practice to assess severity of stenotic and regurgitant valves or to estimate intracavitary pressures. However, this method only evaluates the convective component of the pressure gradient (based on the velocity measurements) and neglects the contribution of inertial forces that can be important, in particular for flow across nonstenotic valves. Digital processing of color Doppler ultrasound data was used to noninvasively estimate both the convective and inertial components of the transmitral pressure difference. Simultaneous pressure and velocity measurements were obtained in six anesthetized open-chest dogs. The instantaneous diastolic transmitral pressure difference is computed from the M mode spatiotemporal velocity distribution using the unsteady flow form of the Bernoulli equation. The inclusion of the inertial forces ([delta PI]max = 0.90 +/- 0.30 mmHg) in the noninvasive pressure difference calculation significantly increased the correlation with catheter-based measurement (r = 0.15 +/- 0.23 vs. 0.85 +/- 0.08; P < 0.0001) and also allowed an accurate approximation of the peak early filling pressure difference ([delta PC+I]max = 0.95[delta Pcath]max + 0.07, r = 0.92, P < 0.001, error: epsilon C+I ([delta PC+I]max-[delta Pcath]max) = 0.01 +/- 0.24 mmHg, N = 90]. Noninvasive estimation of left ventricular filling pressure differences using this technique will improve the understanding of diastolic filling and function of the heart.


Asunto(s)
Ecocardiografía Doppler en Color , Válvula Mitral/fisiología , Animales , Circulación Coronaria , Diástole , Perros , Hemodinámica , Modelos Cardiovasculares , Presión , Factores de Tiempo , Función Ventricular Izquierda
20.
Am Heart J ; 128(5): 927-33, 1994 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-7942486

RESUMEN

Analysis of the flow-convergence zone proximal to a regurgitant orifice permits the noninvasive, quantitative measurement of clinically useful parameters of valvular insufficiency. However, many indexes such as flow rate reflect not only the size of the regurgitant lesion but are also highly dependent on the hemodynamic loading conditions. The effective regurgitant orifice area (ROA) in contrast is a more fundamental parameter, less dependent on hemodynamics and more reflective of real changes in the geometry of the valve, making it a promising index for serial assessment of patients. In this study, the measurement of regurgitant orifice area by the flow-convergence method was tested in tricuspid regurgitation and then used to monitor patients noninvasively over time. The effective ROA was calculated in 45 patients with tricuspid regurgitation by means of the flow-convergence method and compared with the ROA obtained with pulsed Doppler echocardiographic methods. An excellent correlation was obtained between the two assessments of ROA (r = 0.96, delta ROA = -0.09 +/- 6.5 mm2). ROA also showed an excellent correlation with other indexes of valvular insufficiency such as regurgitant stroke volume (r = 0.89) and regurgitant fraction (r = 0.88). In a subgroup of 22 patients thought to be clinically stable, ROA was calculated serially over a mean follow-up period of 2 months and its variability compared with that of other flow-based parameters obtainable from proximal acceleration. The variation between the two studies in regurgitant stroke volume and regurgitant flow rate was 5% +/- 20.6% and 5.2% +/- 35.7%, respectively. The effective ROA showed significantly less variability at 1.8% +/- 15%.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Ecocardiografía Doppler , Ecocardiografía , Insuficiencia de la Válvula Tricúspide/diagnóstico por imagen , Anciano , Velocidad del Flujo Sanguíneo/fisiología , Estudios de Cohortes , Circulación Coronaria/fisiología , Femenino , Estudios de Seguimiento , Humanos , Procesamiento de Imagen Asistido por Computador , Modelos Lineales , Masculino , Volumen Sistólico/fisiología , Factores de Tiempo , Válvula Tricúspide/diagnóstico por imagen , Válvula Tricúspide/fisiopatología , Insuficiencia de la Válvula Tricúspide/epidemiología , Insuficiencia de la Válvula Tricúspide/fisiopatología
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