Transesophageal echocardiography during mitral valve repair underestimates mitral valve area by pressure half-time calculation

BACKGROUND: Mitral valve repair (MVRr) has become the mainstay of surgical treatment for mitral valvular regurgitation. Evaluation of MVRr by intraoperative transesophageal echocardiography (IOE) has been routinely employed to guide the operation. While the main objective of IOE is to assess for residual mitral regurgitation, it is also important to exclude significant mitral stenosis. Utilisation of pressure half-time (PHT) to estimate mitral valve area (MVA) has been shown to be reliable in normal clinical situations. However, in MVRr, the accuracy of MVA calculation by PHT needs to be ascertained. METHODS AND RESULTS: Data from IOE and post-MVRr transthoracic echocardiography (TTE) from the year 1998 to 2002 were analysed and when required, offline PHT measurements were made. The mean time interval between the two echocardiographic examinations was 10.6 (1 to 56) weeks. In our 36 cases, the IOE MVA was found to be 2.1+/-0.5 cm2, with the corresponding TTE MVA to be 2.7+/-1.0 cm2. MVA by PHT with IOE underestimated TTE findings by 0.6+/-0.9 cm2 (95% CI: -0.85 to -0.24, P=0.001). In 6 patients, the IOE MVA was moderately reduced. Subsequent TTE in these patients showed that the MVA was adequate and was significantly underestimated by IOE in 5 of these patients. In all these cases, IOE underestimated MVA by a margin, which may result in a need to revise the repair. CONCLUSION: We find that IOE immediately after MVRr tends to underestimate MVA by PHT calculation. The underestimation by IOE may have clinical importance in cases when MVA by IOE is moderately reduced. Therefore, pressure half-time measurement should not be used to assess mitral valve areas during mitral valve repair.     

Non-invasive assessment of mitral valve area during percutaneous balloon mitral valvuloplasty: role of real-time 3D echocardiography.

BACKGROUND: In the last decade, multiple studies depicted discrepancies between mitral valvular orifice area (MVA) measurements obtained with the pressure half-time (PHT) method and invasive methods during the immediate post-percutaneous mitral valvuloplasty (PMV) period. Our aim was to assess the accuracy of Real-Time 3D echo (RT3D) to measure the MVA in the immediate post-PMV period. The invasively determined MVA was used as the gold standard. METHODS AND RESULTS: We studied 29 patients with rheumatic mitral stenosis from two centres (27 women; mean age 48.2+/-11.3 years), all of which had underwent PMV. MVA was calculated before and after PMV using the PHT method, 2D echo planimetry, RT3D echo planimetry and invasive determination (Gorlin's method). The RT3D MVA assessment showed a better agreement with the invasively derived MVA before and in the immediate post-PMV period (Bland-Altman analysis: Average difference between both methods and limits of agreement: 0.01 (-0.31 to 0.33) cm(2) and -0.12 (-0.71 to 0.47) cm(2)) before and immediately after the PMV, respectively. CONCLUSIONS: RT3D is a feasible and accurate technique for measuring MVA in patients with RMVS. It has the best agreement with the invasively determined MVA, particularly in the immediate post-PMV period.     

Clinical applicability for the assessment of the valvular mitral stenosis severity with Doppler echocardiography and the proximal isovelocity surface area (PISA) method

Evaluation of the severity of valvular mitral stenosis and measurements of the effective rheumatic mitral valve area by noninvasive echocardiography has been well accepted. The area is measured by the two-dimensional planimetry (PLM) method and the Doppler pressure half-time (PHT) method. Recently, the proximal isovelocity surface area (PISA) by color Doppler technique has been used as a quantitative measurement for valvular heart disease. However, this method needs more validation. The aim of this study was therefore to investigate the clinical applicability of the PISA method in the measurements of effective mitral valve area in patients with rheumatic valvular heart disease. Forty-seven patients aged from 23 to 71 years, with a mean age of 53 +/- 13 (25 male and 22 female, 15 with sinus rhythm, mean heart rate of 83 +/- 14 beats per minute, with rheumatic valvular mitral stenosis without hemodynamically significant mitral regurgitation) were included in the study. Effective mitral valve area (MVA) derived by the PISA method was calculated as follows: 2 x Pi x (proximal aliasing color zone radius)2x aliasing velocity/peak velocity across mitral orifice. Effective mitral valve areas measured by three different methods (PLM, PHT, and PISA) were compared and correlated with those calculated by the "gold standard" invasive Gorlin's formula. The MVA derived from PHT, PLM, PISA and Gorlin's formula were 1.00 +/- 0.31cm2, 0.99 +/- 0.30 cm2, 0.95 +/- 0.30 cm2 and 0.91 +/- 0.29 cm2, respectively. The correlation coefficients (r value) between PHT, PLM, PISA, and Gorlin's formula, respectively, were 0.66 (P = 0.032, SEE = 0.64), 0.67 (P = 0.25, SEE = 0.72) and 0.80 (P = 0.002, SEE = 0.53). In conclusion, the PISA method is useful clinically in the measurement of effective mitral valve area in patients with rheumatic mitral valve stenosis. The technique is relatively simple, highly feasible and accurate when compared with the PHT, PLM, and Gorlin's formula. Therefore, this method could be a promising supplement to methods already in use.     

Planimetry of mitral valve stenosis by magnetic resonance imaging

OBJECTIVES: We sought to determine whether noninvasive planimetry of the mitral valve area (MVA) by magnetic resonance imaging (MRI) is feasible and reliable in patients with mitral stenosis (MS). BACKGROUND: Accurate assessment of MVA is particularly important for the management of patients with valvular stenosis. Current standard techniques for assessing the severity of MS include echocardiography (ECHO) and cardiac catheterization (CATH). METHODS: In 22 patients with suspected or known MS, planimetry of MVA was performed with a 1.5-T magnetic resonance scanner using a breath-hold balanced gradient echo sequence (true FISP). Data were compared with echocardiographically determined MVA (ECHO-MVA, n = 22), as well as with invasively calculated MVA by the Gorlin-formula at (CATH-MVA, n = 17). RESULTS: The correlation between MRI- and CATH-MVA was 0.89 (p < 0.0001), and the correlation between MRI- and ECHO-MVA was 0.81 (p < 0.0001). The MRI-MVA slightly overestimated CATH-MVA by 5.0% (1.60 +/- 0.45 cm(2) vs. 1.52 +/- 0.49 cm(2), p = NS) and ECHO-MVA by 8.1% (1.61 +/- 0.42 cm(2) vs. 1.48 +/- 0.42 cm(2), p < 0.05). On receiver-operating characteristic curve analysis, a value of MRI-MVA below 1.65 cm(2) indicated mitral stenosis (CATH-MVA < or =1.5 cm(2)), with a good sensitivity and specificity (89% and 75%, respectively). CONCLUSIONS: Magnetic resonance planimetry of the mitral valve orifice in mitral stenosis offers a reliable and safe method for noninvasive quantification of mitral stenosis. In the clinical management of patients with mitral stenosis, it has to be considered that planimetry by MRI slightly overestimates MVA, as compared with MVA calculated echocardiographically and at catheterization.     

Measurement of vena contracta width for the assessment of severity of mitral stenosis

This study was designed to test whether vena contracta width (VCW) measured by color Doppler flow could be used to assess the severity of mitral stenosis (MS). A secondary objective was to determine the cut-off value of VCW for the prediction of severe MS. We studied 47 consecutive patients with MS (mean age, 50 ± 11 years; 34 females) who did not have more than mild mitral regurgitation. We compared VCW with conventional methods for determining mitral valve area (MVA). Mitral valve area was assessed by one observer using continuity equation (CE), pressure half-time (PHT), and planimetry in the parasternal short axis view. Vena contracta width was measured in the same patients by two observers (blinded to the MVA data) using the apical four-chamber view by color Doppler flow. Vena contracta width measurements were compared with MVA by CE, PHT, and planimetry. The MVA determined by CE, PHT, and planimetry was 1.19 ± 0.42, 1.31 ± 0.53, and 1.27 ± 0.43 cm², respectively. The VCW in patients with MVA <1 cm², 1–1.5 cm², and >1.5 cm² (calculated by the CE method) was 0.77 ± 0.19, 1.13 ± 0.16, and 1.36 ± 0.24 cm, respectively. Vena contracta width was significantly correlated to MVA by planimetry (r = 0.756, P < 0.001), PHT (r = 0.673, P < 0.001), and CE (r = 0.813, P < 0.001). The VCW of patients with MVA ≤1 cm² was significantly smaller than that of patients with MVA >1 cm² determined by the CE method (0.77 ± 0.19 vs 1.26 ± 0.26, P < 0.001). Vena contracta width measurement of 1 cm or less had a sensitivity of 88% and a specificity of 77% for the prediction of severe MS. These results demonstrate that the correlations between VCW and MVA measured by conventional methods were highly significant. In addition, these results suggest that VCW ≤1 cm may indicate the presence of severe mitral stenosis.     

A nomogram for measurement of mitral valve area by proximal isovelocity surface area method

INTRODUCTION: Although its accuracy has been documented in many studies, the proximal isovelocity surface area (PISA) method is not used widely for mitral valve area (MVA) measurement. In this study, we prepared a new nomogram and tested its use in MVA assessment. MATERIAL AND METHODS: The study included 23 patients (age: 27 +/- 5 years) with mitral stenosis, of whom 7 were in atrial fibrillation. The MVA was measured by four methods: planimetry (PL) (reference method), pressure-half time (PHT), conventional PISA (CP), and nomogram (Nomo) methods. The nomogram included two unknowns: (1) r; the radius of the first PISA section; (2) a; the length of the border opposite to the PISA angle in the triangle with both adjacent borders of 1 cm. The nomogram was also tested for its popularity potential by eight echocardiographers, none of whom were included in the author list. RESULTS: Mean MVA(PL) was 1.85 +/- 0.53 cm(2) (range: 0.72-2.99), mean MVA(PHT) was 1.72 +/- 0.56 cm(2) (range: 0.91-3.30), mean MVA(CP) was 1.69 +/- 0.45 cm(2) (range: 0.97-2.54), and MVA(Nomo) was 1.70 +/- 0.44 cm(2) (0.96-2.49). The nomogram correlated with planimetry (r = 0.87; P < 0.001), pressure half-time (r = 0.71; P < 0.001) and conventional PISA (r = 0.99; P = 0.000) methods. The nomogram method also correlated with planimetry in patients with atrial fibrillation (r = 0.81; P = 0.026). The echocardiographers found that the nomogram is superior to the planimetry and conventional PISA methods but inferior to the pressure half-time method in terms of simplicity. CONCLUSION: The new nomogram is potentially helpful in measurement of MVA. It may be used as an additional method in assessing severity of mitral stenosis.     

Is the mitral valve area flow-dependent in mitral stenosis? A dobutamine stress echocardiographic study

OBJECTIVES: The purpose of this study was to compare the effect of changes in flow rate on the mitral valve area (MVA) derived from two-dimensional echocardiographic planimetry and Doppler pressure half-time (PHT) methods in patients with mitral stenosis (MS). BACKGROUND: Dobutamine stress echocardiography has been proposed as a means of assessing the severity of MS. However, data regarding the effect of an increase in flow rate on MVA are limited. If MVA is indeed flow-dependent, this has important implications for the assessment of the severity of MS, particularly in the setting of reduced cardiac output (CO). METHODS: Dobutamine echocardiography was performed in 57 patients with isolated MS who were in sinus rhythm. The MVA was determined by planimetry and Doppler PHT methods. RESULTS: Cardiac output increased by > or =50% in 27 patients (group I) and by <50% in 30 patients (group II). In group I, the MVA by planimetry increased by only 10.6 +/- 2% and the MVA by PHT increased by 21.9 +/- 4.8%. These changes were similar to those observed in group II (10.7 +/- 3% and 14.8 +/- 4%, respectively; p = NS), despite a much smaller increase in CO. A clinically important change (from the severe to mild category) occurred in only one patient when using the PHT method and in none by planimetry. CONCLUSIONS: Changes in flow rate result in small but clinically insignificant changes in echocardiographic MVA measurement. These methods provide an accurate assessment of MS severity in a majority of patients, independent of changes in flow rate.     

Usefulness of three-dimensionally guided assessment of mitral stenosis using matrix-array ultrasound

Two-dimensional (2-D) planimetry is limited by the technical demands, time, and observer variability required to locate the minimal orifice area, limiting the confident clinical reporting of mitral valve area (MVA). In 27 consecutive patients, MVA was determined independently by 2 observers using the conventional 2-D method and a new 3-D-guided method. Using a matrix-array probe, the valve was visualized in a long-axis view and a cursor steered to intersect the leaflet tips and provide a perpendicular short-axis plane viewed side-by-side. Two-dimensional and 3-D-guided methods allowed planimetry in 24 patients. Consistent with better orifice localization, 3-D guidance eliminated the overestimation of internal orifice diameters in the planimetered short-axis view relative to the limiting diameter defined by the long-axis view (for 3-D guidance, 0.73 +/- 0.20 vs 0.73 +/- 0.21 cm, p = 0.98, vs 0.90 +/- 0.27 cm in the 2-D short-axis view, p <0.01). Accordingly, mean values for the smallest orifice area by 3-D guidance were less than by 2-D imaging (1.4 +/- 0.5 vs 1.5 +/- 0.5 cm(2), p <0.01), changing the clinical severity classification in 11 of 24 patients (46%). The 2-D method also overestimated MVA relative to 3-D guidance compared with Doppler pressure halftime and (n = 6) Gorlin areas. Phantom studies verified no differences in resolution for the 2 acquisition modes. Three-dimensional guidance reduced intraobserver variability from 9.8% to 3.8% (SEE 0.14 to 0.06 cm(2), p <0.01) and interobserver variability from 10.6% to 6.1% (SEE 0.15 to 0.09 cm(2), p <0.02). In conclusion, matrix-array technology provides a feasible and highly reproducible direct 3-D-guided method for measuring the limiting mitral orifice area.     

Mitral valve hemodynamic effects of percutaneous edge-to-edge repair with the MitraClip device for mitral regurgitation.

INTRODUCTION: The Endovascular Valve Edge-to-Edge REpair STudies (EVEREST) are investigating a percutaneous technique for edge-to-edge mitral valve repair with a repositionable clip. The effects on the mitral valve gradient (MVG) and mitral valve area (MVA) are not known. METHODS: Twenty seven patients with moderate to severe or severe mitral regurgitation (MR) were enrolled. Echocardiography was performed preprocedure, at discharge, and at 1, 6, and 12 months. Mean MVG was measured by Doppler and MVA by planimetry and pressure half-time, and evaluated in a central core laboratory. Pre- and postclip deployment, simultaneous left atrial/pulmonary capillary wedge and left ventricular pressures were obtained in eight patients. RESULTS: Three patients did not receive a clip, six patients had their clip(s) explanted by 6 months (none for mitral stenosis), and four were repaired with two clips. Results are notable for a slight increase in mean MVG by Doppler postclip deployment (1.79 +/- 0.89 to 3.31 +/- 2.09 mm Hg, P < 0.01) and an expected decrease in MVA by planimetry (6.49 +/- 1.61 to 4.46 +/- 2.14 cm(2), P < 0.001) and by pressure half time (4.35 +/- 0.98 to 3.01 +/- 1.42 cm(2), P < 0.05). There were no significant changes in hemodynamic parameters postclip deployment by direct pressure measurements. There was no change in MVA by planimetry from discharge to 12 months (3.90 +/- 1.90 to 3.79 +/- 1.54 cm(2), P = 0.78). CONCLUSIONS: Echocardiographic and hemodynamic measurements after percutaneous mitral valve repair with the MitraClip show an expected decrease in mitral valve area with no evidence of clinically significant mitral stenosis either immediately after clip deployment or after 12 months of follow-up.     

Can the Proximal Isovelocity Surface Area Method Calculate Stenotic Mitral Valve Area in Patients with Associated Moderate to Severe Aortic Regurgitation? Analysis Using Low Aliasing Velocity of 10% of the Peak Transmitral Velocity

To assess the ability of the proximal isovelocity surface area (PISA) method to accurately measure the stenotic mitral valve area (MVA), and to assess whether aortic regurgitation (AR) affects the calculation, we compared the accuracy of the PISA method and the pressure half-time (PHT) method for determining MVA in patients with and without associated AR by using two-dimensional echocardiographic planimetry as a standard. The study population consisted of 45 patients with mitral stenosis. Seventeen of the 45 patients had associated moderate-to-severe AR. The PISA method was performed using low aliasing velocity (AV) of 10% of the peak transmitral velocity, which provided the most accurate estimation of MVA when compared with planimetry. The maximal radius r of the PISA was measured from the orifice to blue-red aliasing interface. Using the PISA method, MVA was calculated as (2pir(2)) x theta / 180 x AV/Vmax, where theta was the inflow angle formed by mitral leaflets, AV was the aliasing velocity (cm/sec), and Vmax was the peak transmitral velocity (cm/sec). MVA by the PISA method correlated well with planimetry both in patients with AR (r = 0.90, P < 0.001, SEE = 0.17 cm(2)) and without AR (r = 0.92, P < 0.001, SEE = 0.16 cm(2)). However, MVA by the PHT method did not correlate as well with planimetry (r = 0.57, P < 0.05, SEE = 0.37 cm(2)) in patients with associated AR, and the PHT method produced a significant overestimation (24%) of MVA obtained by planimetry in these patients. We conclude that the PISA method allows accurate estimation of MVA and is not influenced by AR.     

Validity of the proximal isovelocity surface area color Doppler method for calculating the valve area in patients with mitral stenosis; comparison with the two-dimensional echocardiographic method]

BACKGROUND. The proximal isovelocity surface area (PISA) method, assessed by color Doppler echocardiography, has gained acceptance as a means of calculating flow rate through regurgitant orifice. The method can also be used to derive mitral valve area (MVA), by continuity equation, in patients with mitral stenosis (MS). The aim of this study was to compare the PISA method with the two-dimensional echocardiographic planimetry (2D) method and pressure half-time method (PHT) in MVA calculations in a group of 37 patients with MS. METHODS AND RESULTS. All of these patients had satisfactory MVA by 2D method. There were 22 female and 15 male; age 56 +/- 11 years (range 32-71); 19 were in sinus rhythm (SR) and 18 in atrial fibrillation (AF); 17 patients had pure MS, while the remaining 20 had associated mitral regurgitation (MR); in 23 patients the orifice morphology was circular or elliptic, and was defined as regular; while in 14 patients the morphology was irregular for the presence of two or more nodular calcifications on the commissures or leaflet's edges. MVA by PISA method was calculated assuming a uniform radial flow convergence region along a hemispherical surface, according to the formula: MVA = 2 pi r2 Vn(1-cos theta)/Vmax; where r was the PISA radius measured in 2D from the first alias to the mitral leaflet's edge; Vn was the flow velocity at radial distance from the mitral orifice; Vmax was the peak transmitral velocity by CW Doppler; 1-cos theta was a factor that accounted for the inflow angle formed by the mitral leaflets. The Nyquist limit was lowered to 29 cm/sec. Alpha angle formed by the mitral leaflets ranged between 86 degrees and 134 degrees; average 110 degrees +/- 10 degrees. 2D MVA was 1.33 +/- 0.37 cm2; range 0.69-2.2 cm2; PHT MVA was 1.29 +/- 0.34 cm2; range 0.70-2.1 cm2; PISA MVA was 1.18 +/- 0.36 cm2; range 0.47-1.95 cm2. The PISA method underestimates MVA by 0.15 +/- 0.21 cm2, in comparison with the 2D method; and by 0.11 +/- 0.18 cm2 in comparison with PHT method (p ns). The correlation between 2D and PISA MVA was: r = 0.84; p < 0.001; y = 0.83x + 0.06; 95% confidence intervals +/- 0.40 cm2; and between PHT and PISA MVA was: r = 0.79; y = 0.84x + 0.09; p < 0.001; 95% confidence intervals +/- 0.46 cm2. The correlation coefficient was similarly good in patients with SR or AF, and did not significantly change in patients with pure MS or MS+MR; neither did it vary with respect to the orifice morphology (p < 0.001 for all the variables considered), except for the correlation PHT-PISA in the group of patients with irregular orifice morphology (r = 0.70; p = 0.005). The interobserver and intraobserver variability were, respectively: 2.2% and 4.4% for 2D MVA; 3.4% and 3.8% for PHT MVA; 5.2% and 3.5% for the PISA radius; 6.1% and 4.4% for the alpha angle; 10.2% and 7.2% for PISA MVA (F ratio of variances ns). CONCLUSIONS. In conclusion, the PISA method allows accurate assessment of MVA in patients with MS, regardless of cardiac rhythm or additional MR. Moreover, our study suggests that orifice morphology does not affect the accuracy of this method.     

Measurement of the mitral area with three-dimensional cardiac echography

Two dimensional planimetry of mitral stenosis is sometimes difficult due to the complex morphology of the mitral valve. Three dimensional cardiac echography images the projected area of the mitral valve allowing precise planimetry of the orifice. Thirty patients with mitral stenosis were included in this study in order to obtain planimetry of the mitral orifice with two dimensional and three dimensional "freehand" mode transthoracic echocardiography. In 10 patients, the measurements were taken before and after percutaneous commissurotomy. The mitral area measured with three dimensional echography was 1.36+/-0.45 cm2 and 1.39+/-0.43 cm2 in two dimensional mode. The correlation between the 2 methods was good (y=1.01x - 0.08, r=0.92, p<0.001) but three dimensional echocardiography significantly underestimated the two dimensional planimetry by 0.05+/-0.27 cm2 (4+/-20%, p<0.05). The intra- and inter-observer reproducibility of the three dimensional measurements were 0.95 and 0.91 respectively. Three dimensional free-hand mode cardiac echography allows precise measurement of the mitral orifice area in patients with mitral stenosis.     

Effect of mitral regurgitation and volume loading on pressure half-time before and after balloon valvotomy in mitral stenosis

Doppler pressure half-time (PHT) is frequently used to assess mitral valve area (MVA), but the reliability of PHT has recently been challenged, specifically in the setting of balloon mitral valvotomy when hemodynamics have been abruptly altered. The effect of volume loading both before and after balloon mitral valvotomy on computation of MVA by Gorlin and by PHT in 18 patients with high-fidelity micromanometer measurements of left atrial and left ventricular pressure was therefore examined. Echocardiographic MVA increased from 0.91 +/- 0.15 to 1.97 +/- 0.42 cm2 after valvotomy. Volume loading produced significant increases in left atrial pressure (16 to 23 before and 12 to 20 mm Hg after valvotomy), in cardiac output (3.7 to 4.1 before and 3.9 to 4.6 liters/min after valvotomy), and in mitral valve gradient (11 to 14 before and 5 to 7 mm Hg after valvotomy). These hemodynamic changes were associated with modest but significant decreases in PHT and increases in MVA estimated by 220/PHT (0.66 to 0.81 before and 1.64 to 1.96 cm2 after valvotomy), whereas the MVA by Gorlin was not affected in a consistent fashion by volume loading (0.85 to 0.89 before and 1.66 to 1.69 cm2 after valvotomy). The correlation between Gorlin MVA and 220/PHT was only fair (r = 0.73, p less than 0.001) and was significantly poorer among patients with greater than 1+ mitral regurgitation (r = 0.72) than among those with less or no regurgitation (r = 0.79) (p = 0.001 by analysis of covariance for mitral regurgitation effect).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of proximal isovelocity surface area method and pressure half time method for evaluation of mitral valve area in patients undergoing balloon mitral valvotomy

Background: The pressure half time (PHT) method is unreliable for measurement of mitral valve area (MVA) immediately after valvotomy. The proximal isovelocity surface area (PISA) method has been used to derive mitral valve area in patients with mitral stenosis. The aim of our study was to compare PISA method and PHT method in patients undergoing percutaneous balloon mitral valvotomy (BMV). Methods: The PISA was recorded from the apex and MVA was calculated using continuity equation by the formula 2πr² Vr/Vm, where 2πr² is the hemispheric isovelocity area, Vr is the velocity at the radial distance "r" from the orifice, and Vm is the peak velocity. A plain angle correction factor (θ)/180 was used to correct the inlet angle subtended by leaflet tunnel as a result of leaflet doming. Results: MVA calculated using PISA method (r = 0.5217, P < 0.0001, SE = 0.016) and PHT (r = 0.6652, P < 0.0001, SE = 0.017) correlated well with 2D method in patients with mitral stenosis before BMV. After BMV, MVA by PISA method correlated well with 2D planimetry (r = 0.5803, P < 0.0001, SE = 0.053) but PHT showed poor correlation (r = 0.1334, P = 0.199, SE = 0.036). The variability of measurement of MVA was most marked with PHT method in the post-BMV period. Conclusion: The PISA method correlates well with 2D planimetry in patients with mitral stenosis before and after BMV and is superior to the PHT method in the post-BMV period where the latter may be unreliable.     

Mitral balloon valvotomy using the Inoue balloon technique for selected patients with severe pliable rheumatic mitral valve stenosis: immediate and short-term results

We selected 40 patients with severe symptomatic rheumatic mitral stenosis for balloon valvotomy using the Inoue balloon technique. The patients' mean age was 31 +/- 14 years and there were 24 females and 16 males. The patients were selected according to the following echo/Doppler criteria; 1. Severe mitral stenosis, i. e. mitral valve area (MVA) less than 1.1 cm2; 2. pliable anterior mitral valve leaflet; 3. absence of calcification of the mitral commissures and 4. absence of significant subvalvular mitral valve disease (Block echo score less than 8). We failed to cross the mitral valve in three cases and repeat attempts in two patients with higher transeptal puncture was successful. Thirty-nine procedures were technically successful (98%). There were no complications. We used an Inoue balloon size 24-30 mm using echo/Doppler guided stepwise mitral dilatation. After mitral balloon valvotomy, the MVA increased from 0.8 +/- 0.2 to 1.7 +/- 0.5 cm2 (p less than 0.001). Five patients developed mild mitral regurgitation and in one patient the degree of mitral regurgitation increased from mild to moderate. The mean mitral valve area 48 hours after the procedure measured 1.9 +/- 0.4 cm2 (echo/Doppler); one patient (2.5%) had residual mitral stenosis (MVA less than 1.5 cm2). At six weeks follow-up study the mean mitral valve area was 1.9 +/- 0.5 cm2 (Echo/Doppler), with no restenosis. We conclude that in selected cases of severe pliable mitral stenosis, the Inoue balloon technique achieves a greater than 100% increase of the MVA, without inducing significant iatrogenic mitral regurgitation or residual stenosis.     

Application of the vena contracta method for the calculation of the mitral valve area in mitral stenosis

OBJECTIVES: The vena contracta is the narrowest region of the regurgitant or stenotic jet just downstream the orifice and reflects the size of that orifice. This study was performed to assess the accuracy of the vena contracta width (VCW) in evaluating the severity of mitral stenosis (MS) and to compare the mitral valve area (MVA) determined by VCW with MVAs obtained by other more traditional echocardiographic methods. METHODS: We studied 59 patients (43 females, 42 +/- 14 years) with MS. VCW was measured in the apical four chamber view by Doppler color flow mapping. The largest diameter of the VCW during diastole was measured for at least three cardiac cycles and averaged. MVA was calculated from the following equation: pir(2), where r = VCW/2. MVA was also determined by planimetry, the pressure half-time method, and by the Gorlin formula. RESULTS: In this study, the width of the vena contracta ranged from 0.89 to 1.73 cm (mean 1.30 +/- 0.21). MVA, calculated based on the VCW, ranged from 0.63 to 2.35 cm(2) (mean 1.36 +/- 0.41). MVA by VCW (1.36 +/- 0.41 cm(2)) showed good correlations with three comparative techniques: (1) the cross-sectional area by planimetry (1.35 +/- 0.36 cm(2), mean difference = 0.21 +/- 0.16 cm(2), y = 0.91x + 0.14, r = 0.79, SEE = 0.26 cm(2), p < 0.001); (2) the area derived from the Doppler pressure half-time (1.27 +/- 0.32 cm(2), mean difference = 0.22 +/- 0.19 cm(2), y = 0.97x + 0.13, r = 0.76, SEE = 0.27 cm(2), p < 0.001), and (3) the area derived from the Gorlin equation in the 18 patients who underwent catheterization (1.27 +/- 0.35 cm(2), mean difference = 0.19 +/- 0.16, y = 0.98x + 0.05, r = 0.81, SEE = 0.26 cm(2), p < 0.001). CONCLUSIONS: These findings suggest that Doppler color flow imaging of the MS jet in the vena contracta can provide an accurate estimation of MVA and appears to be potentially applicable in the assessment of the severity of MS.     

Sequential assessment of mitral valve area during diastole using colour M-mode flow convergence analysis: new insights into mitral stenosis physiology.

AIMS: In mitral stenosis (MS) transvalvular flow and velocity continually change throughout diastole but for mitral valve area (MVA), flow-dependent variations (valve reserve) are unknown. These physiologic changes can be studied by the proximal isovelocity surface area (PISA) method, using the high temporal resolution of colour M-mode, essential for simultaneous measurements of flow and velocity. Hence, we aimed to validate the colour M-mode PISA method for measurement of MVA in MS and to define using this method the physiologic flow-dependent changes of MVA during diastole. METHODS AND RESULTS: In 50 patients with native MS, MVA was measured by planimetry (MVA-2D), Doppler pressure half-time (MVA-PHT), and two-dimensional PISA (2D-PISA). MVA measurement by colour M-mode PISA in early diastole (M-PISA) (1.27+/-0.46 cm(2)) with rigorously timed flow and velocity measurements by continuous wave Doppler did not differ and correlated well with MVA-2D (1.29+/-0.44 cm(2), p=0.59; r=0.85, p<0.001) and MVA-PHT (1.30+/-0.41 cm(2), p=0.52; r=0.80, p<0.001). In contrast a trend towards underestimation of MVA by 2D-PISA was observed (1.23+/-0.42 cm(2); p=0.10 and p=0.07). Timed analysis of transvalvular haemodynamics at early, mid, mid-late, and late diastole showed marked changes in flow and velocities (both p<0.0001) but not in MVA (respectively 1.27+/-0.46, 1.29+/-0.47, 1.28+/-0.51 and 1.27+/-0.49 cm(2); ns). CONCLUSIONS: In MS, the high temporal resolution of colour M-mode PISA allows accurate MVA measurements. It also allows for the first time, sequential MVA assessment during diastole. Notwithstanding marked flow and velocities changes, MVA remained unchanged throughout diastole underscoring the lack of flow-related valvular reserve in MS.     

Real-time three-dimensional echocardiography for rheumatic mitral valve stenosis evaluation: an accurate and novel approach

OBJECTIVES: Our aim was to assess which echo-Doppler method has the best agreement with the mitral valve area (MVA) invasively evaluated by the Gorlin's formula. We also evaluated the feasibility and reproducibility of real-time three-dimensional echocardiography (RT3D) for the estimation of MVA and the Wilkins score in patients with rheumatic mitral stenosis (RMVS). BACKGROUND: Real-time three-dimensional echocardiography is a novel technique that allows us to visualize the mitral valvular anatomy in any desired plane orientation. The usefulness and accuracy of this technique for evaluating RMVS has not been established. METHODS: We studied a series of consecutive patients with RMVS from two tertiary care hospitals. Mitral valvular area was determined by conventional echo-Doppler methods and by RT3D, and their results were compared with those obtained invasively. Real-time three-dimensional echocardiography planimetry and mitral score were measured by two independent observers and then repeated by one of them. RESULTS: Eighty patients with RMVS comprised our study group (76 women; 50.6 +/- 13.9 years). Compared with all other echo-Doppler methods, RT3D had the best agreement with the invasively determined MVA (average difference between both methods and limits of agreement: 0.08 cm(2) [-0.48 to 0.6]). Interobserver variability was as good for RT3D (intraclass correlation coefficient [ICC] = 0.90) as for pressure half-time (PHT) (ICC = 0.95). For PHT and RT3D, the intraobserver variability was similar (ICC 0.92 and 0.96, respectively). Real-time three-dimensional echocardiography valvular score evaluation showed a better interobserver agreement with RT3D than with 2D echocardiography. CONCLUSIONS: Real-time three-dimensional echocardiography is a feasible, accurate, and highly reproducible technique for assessing MVA in patients with RMVS. Real-time three-dimensional echocardiography has the best agreement with invasive methods.     

Mechanisms of increase in mitral valve area and influence of anatomic features in double-balloon, catheter balloon valvuloplasty in adults with rheumatic mitral stenosis: a Doppler and two-dimensional echocardiographic study

To study the mechanism of increase in the mitral valve area (MVA) and the anatomic features of the mitral valve that may affect the results of catheter double-balloon valvuloplasty (CBV) in adult patients with mitral stenosis, Doppler and two-dimensional echocardiography was performed in 12 patients before and immediately after CBV. Immediately after CBV, there was an increase in the transverse diameter of the mitral valve orifice from 18 +/- 1.6 to 25 +/- 2.8 mm (mean +/- SD, p less than .001). The anterior angles at the commissure increased from 33 +/- 6 to 57 +/- 20 degrees (p less than .05) and the posterior angles from 36 +/- 9 to 54 +/- 14 degrees (p less than .05). The MVA was greater after CBV in patients with pliable mitral valves (2.6 +/- 0.7 cm2) compared with those with rigid mitral valves (1.9 +/- 0.8 cm2; p = .08). After CBV, MVA was smaller in patients with calcification (2.1 +/- 0.2 cm2) compared with those without (2.7 +/- 0.5 cm2; p = .10) and in those with subvalvular disease (2.0 +/- 0.6 cm2) compared with those without (2.9 +/- 0.9 cm2;p = .03). The MVA by Doppler ultrasound before CBV (1.0 +/- 0.2 cm2) correlated well with MVA by cardiac catheterization (1.0 +/- 0.3 cm2; r = .8, SEE = 0.2 cm2). After CBV, the correlation of MVA by Doppler ultrasound (2.0 +/- 0.5 cm2) with MVA by cardiac catheterization (2.4 +/- 0.8 cm2) was poor (r = .3, SEE = 0.44 cm2).(ABSTRACT TRUNCATED AT 250 WORDS)