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

Functional mitral regurgitation

PURPOSE OF REVIEW

Functional mitral regurgitation (FMR) is a complex condition in which significant mitral regurgitation coexist with cardiomyopathy and heart failure and carries an increased risk for associated morbidity and mortality. In addition to guideline-directed medical therapy and cardiac resynchronization therapy, percutaneous transcatheter mitral valve repair (TMVr) is a new therapeutic option but requires careful selection of the proper candidates. We describe the different mechanisms of functional mitral regurgitation, review echocardiographic parameters to assess its severity, and discuss recently published relevant studies including TMVr.

RECENT FINDINGS

Two randomized controlled trials assessing the efficacy and safety of TMVr using the MitraClip in patients with heart failure and severe functional mitral regurgitation were published: MITRA-FR (Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation) and COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation). The results of these trials were opposite: although MITRA-FR failed to show clinical benefit, COAPT showed a dramatic clinical and echocardiographic benefit from transcatheter mitral valve repair using the MitraClip device. We discuss these two important trials and how differences in patient enrollment could explain the discrepant results and the manner they may influence future studies and clinical practice.

SUMMARY

Patients with FMR receiving optimal guideline-directed medical therapy and cardiac resynchronization therapy who meet specific clinical and echocardiographic criteria can benefit from transcatheter mitral valve repair.

Clinical manifestations, diagnosis, and treatment of ischemic mitral regurgitation: a review

Ischemic mitral regurgitation (IMR) is a frequent complication after acute myocardial infarction (AMI) associated with a worse prognosis. The pathophysiological mechanisms of IMR are not fully understood, but it is known to be a complex process in which ventricular remodelling is the main causal factor. The various imaging techniques in cardiology and echocardiography fundamentally have contributed significantly to clarify the mechanisms that cause and progressively aggravate IMR. At present, different therapeutic options, the most important of which are cardio-surgical, address this problem. Nowadays the improvement in cardiac surgery and transcatheter therapies, have shown a therapeutic advance in IMR management. IMR is a predictor of poor prognosis in patients with heart failure and depressed left ventricular (LV) systolic function. However, it remains controversial whether mitral regurgitation (MR) in these patients is a consequence of dilation and dysfunction of the LV, or whether it contributes to worsening the prognosis of the ventricular dysfunction. Given that echocardiography has a fundamental reference role in the identification, graduation of severity and evaluation of the therapeutics used in the treatment of MR, we are going to focus on it over the rest of the imaging techniques. In contrast to primary MR the benefits of mitral surgery in patients with secondary MR are uncertain. Therefore, we will comment fundamentally on the role of mitral surgery in patients with IMR, with an update of the different surgical interventions available, without forgetting to mention the other therapeutic options currently available.

Multimodality imaging for the quantitative assessment of mitral regurgitation

The natural history of mitral regurgitation (MR) results in significant morbidity and mortality. Innovations in non-invasive imaging have provided new insights into the pathophysiology and quantification of MR, in addition to early detection of left ventricular (LV) dysfunction and prognostic assessment in asymptomatic patients. Transthoracic (TTE) and transesophageal (TOE) echocardiography are the mainstay for diagnosis, assessment and serial surveillance. However, the advance from 2D to 3D imaging leads to improved assessment and characterization of mitral valve (MV) disease. Cardiovascular magnetic resonance (CMR) is increasingly used for MR quantitation and can provide an alternative imaging method if echocardiography is suboptimal or inconclusive. Other techniques such as exercise echocardiography, tissue Doppler imaging and speckle-tracking echocardiography can further offer complementary information on prognosis. This review summarises the current evidence for state-of-the-art cardiovascular imaging for the investigation of MR. Whilst advanced echocardiographic techniques are superior in the evaluation of complex MV anatomy, CMR appears the most accurate technique for the quantification of MR severity. Integration of multimodality imaging for the assessment of MR utilises the advantages of each imaging technique and offers the most comprehensive assessment of MR.

An easy-to-use scoring index to determine severity of mitral regurgitation by 2D echocardiography in clinical practice

PURPOSE

Mitral regurgitation (MR) grading by two-dimensional transthoracic echocardiography is challenging, but important to determine the best treatment strategy in patients with MR. Current guidelines advocate an integrative approach, although no recommendation is provided on how to do so. An easy-to-use index will be helpful for standardized and reproducible MR grading.

METHODS

Eleven echocardiographic parameters were retrospectively evaluated in 145 patients with moderate or severe MR. Parameters were scored positive or negative for severe MR, where expert panel consensus reading was considered as the reference standard. Logistic regression was performed, and adjusted coefficients were used to create a risk score for severe MR per patient (ROSE-index). The best cutoff with corresponding predictive values was determined.

RESULTS

Eighty-two percent of all parameters could be determined. Multivariable analysis revealed five parameters that remained significant predictors for severe MR: morphology, jet characteristics, vena contracta, systolic reversal, and left ventricular dimensions. With different weighing, a total score of 8 could be obtained. Median total ROSE-index score for moderate (2.0) and severe MR (5.0) did significantly differ. The cutoff score (≥4) revealed sensitivity 0.84 and specificity 0.83 to diagnose severe MR. Negative predictive value was 100% for score 0 and 1; score 6-8 showed a 100% positive predictive value. Inter- and intra-observer agreements were excellent (K-values >0.80).

CONCLUSION

Here, we propose an easy-to-use tool for integrated analysis of guideline parameters to assess MR severity. Using this so-called ROSE-index revealed reliable and reproducible assessment of severe MR (cutoff≥4) that may be helpful for clinical decision making.

Primary mitral valve regurgitation: Update and review

Mitral regurgitation is the second most common valvular disorder requiring surgical intervention worldwide. This review summarizes the current understanding of primary, degenerative mitral regurgitation with respect to etiology, comprehensive assessment, natural history and management. The new concept of staging of the valvular disorders, newer predictors of adverse and controversy of “watchful waiting” versus “early surgical intervention” for severe, asymptomatic, primary mitral regurgitation are addressed.

Dynamics of Concomitant Functional Mitral Regurgitation in Patients with Aortic Stenosis Undergoing TAVI

BACKGROUND

The aim of this study was to investigate the echocardiographic features of functional mitral regurgitation (MR) in patients with aortic stenosis (AS) pre- and post-trans catheter aortic valve implantation (TAVI).

METHODS

The study subjects consisted of 79 patients with severe AS, who underwent TAVI. The echocardiographic parameters related to MR severity prior to TAVI and the change in these parameters and MR severity within one month after implantation were retrospectively evaluated.

RESULTS

The mean left ventricular ejection fraction (LVEF) was 53 ± 12%, and the mean MR severity was 1.2 ± 0.7. Among the baseline parameters, age (p = 0.019, r = 0.264), LV mass (p = 0.017, r = 0.269), deceleration time (DT) (p = 0.019, r = -0.266), left atrial diameter (p = 0.003, r = 0.325), were related to pre-procedure MR severity. After TAVI, the grade of MR (1.2 ± 0.7 vs. 0.8 ± 0.6, p < 0.001) and MR duration (43 ± 19% vs. 31 ± 23%, p < 0.001) were significantly decreased. The grade of pre-procedural MR (p < 0.001) was a predictor of residual MR after TAVI. However, there was not a significant change in the left ventricular echocardiographic parameters after TAVI [LVEF (53 ± 12 vs. 52 ± 11, p = 0.285), and LV mass (302 ± 84 vs. 306 ± 76 g, p = 0.495)].

CONCLUSIONS

In patients with severe AS, functional MR is related to age, LV mass, DT and left atrial diameter. TAVI improves MR in these patients, even before LV remodelling occurs.

Usefulness of three-dimensional transesophageal echocardiography in retrieval of a dislodged vascular plug used to close paraprosthetic mitral regurgitation

In this report, we describe a case of periprocedural dislodgement of an Amplatzer Vascular Plug II device during percutaneous closure of severe paraprosthetic mitral regurgitation. The free plug in the left atrium was successfully retrieved percutaneously using a snare inserted through a sheath under live/real time three-dimensional transesophageal echocardiographic guidance. This proved crucial not only in guiding device deployment but also in detecting and helping management of complications.

Ischemic mitral regurgitation: pathophysiology, diagnosis and surgical treatment

Ischemic mitral valve regurgitation often complicates acute myocardial infarction and also represents a negative prognostic factor for long-term survival in patients undergoing surgical myocardial revascularization. While severe mitral regurgitation should always be corrected during a coronary artery bypass operation, the decision making is more difficult in patients with a mild-to-moderate degree of regurgitation. Recent studies and experimental protocols have elucidated the pathophysiological mechanisms leading to mitral regurgitation with great interest in annular modifications and subvalvular alterations. These data suggest that new and integrated surgical approaches that address annuloplasty ring sizing, ring type selection and tethering phenomenon (i.e., chordal cutting, 'edge-to-edge' technique and left-ventricular plasty techniques) are required for a safer and durable valve repair. Transthoracic and transesophageal echocardiography are useful in determining the etiology and the degree of mitral regurgitation, to assess mitral deformation and to measure indexes of global and regional left-ventricular remodeling. Stress echocardiography may unmask higher degrees of mitral regurgitation. More data are needed in order to confirm the promising and interesting preliminary experimental findings of magnetic resonance imaging in diagnosis and clinical evaluation of ischemic mitral regurgitation.

Comparison of real-time three-dimensional transesophageal echocardiography to two-dimensional transesophageal echocardiography for quantification of mitral valve prolapse in patients with severe mitral regurgitation

Real-time 3-dimensional (3D) transesophageal echocardiography (TEE) provides more accurate geometric information on the mitral valve (MV) than 2-dimensional (2D) TEE. The aim of this study was to quantify MV prolapse using real-time 3D TEE in patients with severe mitral regurgitation. In 102 patients with severe mitral regurgitation due to MV prolapse and/or flail, 2D TEE quantified MV prolapse, including prolapse gap and width in the commissural view. Three-dimensional TEE also determined prolapse gap and width with the use of the 3D en face view. On the basis of the locations of MV prolapse, all patients were classified into group 1 (pure middle leaflet prolapse, n = 50) or group 2 (involvement of medial and/or lateral prolapse, n = 52). Prolapse gap and prolapse width determined by 3D TEE were significantly greater than those by 2D TEE (all p values <0.001). The differences in prolapse gap and prolapse width between 2D TEE and 3D TEE were significantly greater in group 2 than group 1 (Δ gap 1.3 ± 1.4 vs 2.4 ± 1.8 mm, Δ width 2.5 ± 3.0 vs 4.4 ± 5.1 mm, all p values <0.01). The differences in prolapse gap and width between 2D TEE and 3D TEE were best correlated with 3D TEE-derived prolapse width (r = 0.41 and r = 0.74, respectively). Two-dimensional TEE underestimated the width of MV prolapse and leaflet gap compared to 3D TEE. Two-dimensional TEE could not detect the largest prolapse gap and width, because of the complicated anatomy of the MV. In conclusion, 3D TEE provided more precise quantification of MV prolapse than 2D TEE.

Comparison of intraoperative three-dimensional Doppler color flow mapping to assess mitral regurgitation

BACKGROUND

Three-dimensional (3D) transesophageal echocardiography (TEE) enables the determination of the vena contracta area (VCA), which is an approved parameter to quantify mitral regurgitation (MR). The aim of this study was to determine the VCA in the operative setting and to compare it to alternative 3D and standard 2D methods, with respect to different etiologies of MR.

METHODS

MR in 56 consecutive patients undergoing cardiac surgery was evaluated using 2D and 3D TEE. VCA, vena contracta (VC), and effective regurgitation orifice area (EROA) by 3D and 2D flow convergence methods were determined. The correlations among the methods and the determined areas were evaluated.

RESULTS

EROA determination using 3D flow convergence areas correlated strongly with VCA (r = 0.653), however the resulting areas were considerably smaller. VC measurements in the 3D data set correlated slightly less (r = 0.629). EROA, which was determined using 2D flow convergence areas, showed the strongest correlation among the 2D methods (r = 0.406). 2D VC measurements showed weak to no correlation with VCA. Although a correlation was detected when using the biplane method or the midesophageal long-axis view to measure VC, statistical significance was only reached in functional MR and MR due to simple prolapse.

CONCLUSIONS

Intraoperative 3D methods to determine MR were feasible and showed improved correlation with VCA compared to 2D measurements. The agreement of 2D methods with VCA declined from functional MR to MR due to prolapse. We recommend the utilization of 3D color Doppler for intraoperative evaluation of MR, especially in patients with complex mitral valve prolapses.

Mechanism and severity of mitral regurgitation by transesophageal echocardiography in patients referred for percutaneous valve repair

Percutaneous mitral valve repair with the MitraClip has been shown to decrease mitral regurgitation (MR) severity, left ventricular volumes, and functional class in patients with severe (3+ or 4+) MR. Determination of which patients are optimal candidates for MitraClip therapy versus surgery has not been rigorously evaluated. Transesophageal echocardiography was prospectively performed in 113 consecutive patients referred for potential MitraClip therapy under the REALISM continued access registry. MR severity was assessed quantitatively in all patients. Mitral valve anatomy and feasibility of MitraClip placement were assessed by transesophageal echocardiography and clinical parameters. MR was degenerative (mitral valve prolapse) in 60 patients (53%), functional (anatomically normal) in 44 (39%), and thickened with restricted motion (Carpentier IIIB classification) in 9 (8%). MR was mild in 19 patients (17%), moderate in 27 (24%), and severe (3 to 4+) in 67 (59%) by Transesophageal echocardiography. MitraClip placement was performed in only 17 of 113 patients (15%); all were successful. Surgical mitral valve repair was performed in 25 patients (22%), mitral valve replacement in 12 (11%). Most patients (59 of 113, 52%) were treated medically, usually because MR was not severe enough to warrant intervention. In conclusion, most patients referred for MitraClip therapy do not have severe enough MR to warrant intervention. Of those with clinical need for intervention, surgery is more often recommended for anatomic or clinical reasons. Three-dimensional transesophageal echocardiography with quantitative assessment of MR severity is helpful in evaluating these patients.

European Association of Echocardiography recommendations for the assessment of valvular regurgitation. Part 2: mitral and tricuspid regurgitation (native valve disease)

Mitral and tricuspid are increasingly prevalent. Doppler echocardiography not only detects the presence of regurgitation but also permits to understand mechanisms of regurgitation, quantification of its severity and repercussions. The present document aims to provide standards for the assessment of mitral and tricuspid regurgitation.

Intraoperative echocardiography in valvular heart disease: an evidence-based appraisal

Intraoperative (IO) transesophageal echocardiography (TEE) is widely used for assessing the results of valvular heart disease (VHD) surgery. Epiaortic ultrasonography (EAU) has been recommended for prevention of perioperative strokes. To what extent does high-quality evidence justify the widespread use of these imaging modalities? In March 2009, we searched MEDLINE (PubMed and OVID interfaces) and EMBASE for studies published in English using database-specific controlled vocabulary describing the concepts of IOTEE, cardiac surgery, VHD, and EAU. We found no randomized trials or studies with control groups assessing the impact of IOTEE in VHD surgery. Pooled analysis of 8 observational studies including 15,540 patients showed an average incidence of 11% for prebypass surgical changes and 4% for second pump runs, suggesting that patients undergoing VHD surgery may benefit significantly from IOTEE, particularly from postcardiopulmonary bypass IOTEE in aortic repair and mitral repair and replacement, but less so in isolated aortic replacement. Further available indirect evidence was satisfactory in the test accuracy and surgical quality control aspects, with low complication rates for IOTEE. The data supporting EAU included 12,687 patients in 2 prospective randomized studies and 4 nonrandomized, controlled studies, producing inconsistent outcome-related results. Despite low-quality scientific evidence supporting IOTEE in VHD surgery, we conclude that indirect evidence supporting its use is satisfactory and suggests that IOTEE may offer considerable benefit in valvular repairs and mitral replacements. The value of IOTEE in isolated aortic valve replacement remains less clear. Evidence supporting EAU is scientifically more robust but conflicting. These findings have important clinical policy and research implications.

Echocardiographic quantitation of mitral regurgitation

Mitral valve regurgitation is a common valvular problem, particularly in developing nations. It causes significant morbidity and mortality, especially if the severity of valve regurgitation is underestimated. Echocardiography plays a significant role in the diagnoses, serial follow-up and management of patients with valvular heart disease. However, precise quantitation of the severity of mitral regurgitation is a crucial element in the therapeutic decisions for managing mitral regurgitation. An accurate assessment of the severity of mitral regurgitation allows for optimal timing of surgical intervention, culminating in improved patient outcomes. This review provides a systematic approach to the quantitation of mitral regurgitation using the echocardiography and Doppler methodologies that are available in the modern noninvasive imaging and hemodynamic laboratory. Additional, novel and evolving noninvasive imaging modalities are reviewed briefly.

Diagnostic Value of Color Flow Mapping and Doppler Echocardiography in the Quantification of Mitral Regurgitation in Patients with Mitral Valve Prolapse or Rheumatic Heart Disease

OBJECTIVES

The objective was to analyze the diagnostic value of the echocardiographic methods used for quantification of mitral regurgitation (MR) in patients with mitral valve prolapse (MVP) or rheumatic heart disease (RHD).

METHODS

The study included 50 patients with MR (mean age of 46.1 years; 35 women), 27 (54%) with RHD and 23 (46%) with MVP. Quantification of the mitral valve regurgitation was obtained by regurgitant orifice area (ROA) and regurgitant volume (RV) by the flow convergence region (FCR) and two-dimensional Doppler echocardiographic methods, regurgitant fraction, jet area (JA), jet area/left atrial area ratio (JA/LAA), and vena contracta (VC). Patients were clinically followed to identify cardiovascular events. Data were analyzed by Pearson, kappa, and receiver operator characteristic curve tests; significance was defined as a P value less than .05.

RESULTS

The correlation between the two methods for ROA and RV were r = 0.79 and r = 0.80, respectively, and between these parameters and regurgitant fraction, VC, JA, and JA/LAA varied from r = 0.54 to r = 0.94 (P lt; .05); the agreement varied from kappa = 0.19 to kappa = 0.83. The highest accuracy to identify patients with clinically significant MR (events at follow-up) was 96% for ROA by FCR, 94% for VC, 86% for RV by FCR, and 86% for JA. No method showed a significant difference between MVP and RHD.

CONCLUSIONS

The methods analyzed had significant correlation and good agreement. ROA by FCR and VC had the best performance to identify severe MR; no significant difference between MVP and RHD was observed.

Valvular heart disease is associated with nonfocal neuropsychiatric systemic lupus erythematosus

BACKGROUND

Central nonfocal neuropsychiatric systemic lupus erythematosus (NPSLE) manifests as cognitive dysfunction, acute confusional state, seizures, and psychosis. Valvular heart disease (VHD) is currently not a causal consideration of nonfocal NPSLE.

OBJECTIVE

The objective of this study was to determine whether VHD is associated with nonfocal NPSLE.

METHODS

Twenty-eight patients with SLE underwent: 1) clinical and laboratory evaluations; 2) neuropsychiatric evaluation; 3) brain magnetic resonance imaging (MRI); and 4) transesophageal echocardiography (TEE). Their findings were compared with those of 28 age- and-sex matched healthy volunteers.

RESULTS

Eighteen patients (64%) had nonfocal NPSLE. Cerebral infarcts on MRI were more common in patients with than without NPSLE (50% vs 10%, P=0.048) and antiphospholipid antibodies (aPL) were associated with old cerebral infarcts (P=0.03). Valvular heart disease was detected in 20 patients (71%) of whom 20 (71%) had valve thickening, 17 (61%) had valve regurgitation, and 15 (53%) had valve vegetations (12 on the mitral valve). Mitral valve vegetations were more common in patients with than without nonfocal NPSLE and in those with old cerebral infarcts (61% vs 10% and 75% vs 30%, respectively, P<or=0.02 for both). The nonneurologic activity of SLE and mitral valve vegetations were the only independent predictors of NPSLE (odds ratio [OR], 1.27 per unit value; confidence interval [CI], 1.1-1.6; P=0.03; and OR, 16.5; CI, 1.26-217; P=0.03, respectively). Among controls, none had neuropsychiatric syndromes, 4 (15%) had MRI abnormalities, and 3 (11%) had VHD (all P<or=0.001 vs patients).

CONCLUSIONS

Nonfocal NPSLE, cerebral infarcts, and VHD were highly associated and mitral valve vegetations were independent predictors of NPSLE. Thus, VHD exacerbated by hypercoagulability may cause thromboembolic ischemic brain injury and nonfocal NPSLE.

Doppler Echocardiographic Assessment of Valvular Regurgitation Severity by Measurement of the Vena Contracta: An In Vitro Validation Study

BACKGROUND

Noninvasive quantitation of valvular regurgitation remains a difficult problem. Measurements of the vena contracta (VC) by color Doppler echocardiography have been proposed but limited data are available on the actual accuracy of this method.

METHODS

To evaluate how closely the color Doppler VC reflects the true fluid dynamic VC and the anatomic regurgitant orifice and whether this measurement is affected by flow changes, various models of valvular regurgitation were studied in an in vitro flow circuit. The VC diameter was measured with color Doppler using two different ultrasound systems (Agilent Sonos 5500; Agilent Technologies Inc, Palo Alto, Calif and Vingmed CFM 800; GE Healthcare, Chalfront St Giles, UK). Optical planimetry of the anatomic regurgitant orifice was performed, the true VC diameter was determined by laser particle flow visualization.

RESULTS

Because of flow contraction, the true VC diameter was consistently smaller than the anatomic regurgitant orifice diameter. Anatomic orifice and true VC only marginally changed with flow rate. The diameter of the color Doppler VC, however, not only overestimated the anatomic orifice diameter by 45% to 60% and the true VC diameter by 130% to 160%, but was also highly affected by the flow rate and the ultrasound system. Despite these limitations a color Doppler VC diameter of 0.77 cm or more (Agilent) and 0.89 cm or more (Vingmed) detected severe regurgitation with a sensitivity of 93% and 84% and a specificity of 96% and 79%, respectively.

CONCLUSIONS

Color Doppler estimates of the VC markedly overestimate regurgitant orifice and true VC. In contrast to the true VC, Doppler measurements are significantly affected by flow rate and by the ultrasound system used. Nevertheless, they allow semiquantitative assessment of valvular regurgitation separating severe from nonsevere regurgitation with acceptable accuracy.

Transthoracic and Transesophageal Echocardiographic Assessment of Mitral Regurgitation Severity: Usefulness of Qualitative and Semiquantitative Techniques

In this report, we review the advantages, limitations, and optimal utilization of various transthoracic and transesophageal echocardiographic (TTE and TEE) methods used for assessing mitral regurgitation (MR) as published in full-length, peer-reviewed articles since the color Doppler era began in 1984. In addition, comparison is made to other imaging modalities including catheter-based, magnetic resonance and surgical assessment of MR. Although left ventricular (LV) angiography has been traditionally used for validation of various TTE methods and is time-honored, its considerable limitations preclude it from being a real "gold standard." Based on the reviewed literature, no clear "gold standard" for the assessment of MR can be identified at present, but newly emerging TTE and TEE techniques, such as three-dimensional color Doppler, may have the potential to overcome some of the limitations of the two-dimensional methods.

Valvular heart disease as a cause of cerebrovascular disease in patients with systemic lupus erythematosus

Thirty-seven patients with systemic lupus erythematosus underwent complete clinical and laboratory evaluations, including antiphospholipid antibodies and lupus anticoagulant, magnetic resonance imaging of the brain, and transesophageal echocardiography. Cerebrovascular disease manifested as stroke, transient ischemic attack, or cerebral infarcts in patients with nonfocal neurologic deficits was detected in 19 patients (51%), and significant left-sided valvular heart disease in 25 (68%). Valve vegetations, valve thickening, valve regurgitation, and lupus anticoagulant antibody occurred 2 to 3 times more often in patients with than without cerebrovascular disease (all p < or =0.04) and were the only independent predictors of cerebrovascular disease (odd ratios 5.3 to 10.6, all p < or =0.03). Thus, valvular heart disease probably exacerbated by hypercoagulability appears to be a source of embolic ischemic brain injury and cerebrovascular disease.

[Quantification of valvular lesions in patients with left ventricular dysfunction]

Echocardiography is the preferred method for assessment of aortic and mitral valvular lesions. The pressure gradient in aortic stenosis may be misleading in patients with poor left ventricular function. Aortic valve area planimetry by transesophageal echocardiography results in a flow independent anatomic measurement. Low-dose dobutamine stress echocardiography provides important prognostic information. Quantitative Doppler echocardiography allows accurate assessment of mitral regurgitation severity. However, the definition of what is severe mitral regurgitation is different in patients with left ventricular dysfunction.

Assessment of the tricuspid valve in hypoplastic left heart syndrome

Hypoplastic left heart syndrome has provided the pediatric cardiology community one of its largest challenges. Until the mid-1980s, the mortality for this lesion was close to 100%. Through the pioneering work of Bill Norwood,1 Len Bailey,2 and the continued work of many pediatric cardiologists and surgeons, the current five-year survival for staged Norwood palliation and cardiac transplantation is now approximately 75%.3,4

Color flow imaging of the vena contracta in mitral regurgitation: technical considerations

Qualitative grading of mitral regurgitation severity has significant pitfalls secondary to hemodynamic variables, sonographic technique, blood pool entrainment, and the Coanda effect. Volumetric and proximal isovelocity surface area methods can be used to quantitate regurgitant orifice area, regurgitant volume, and regurgitant fraction, but have several limitations and can pose technical challenges. The vena contracta width method provides a rapid and accurate quantitative assessment of mitral regurgitation severity, but is clinically underused. This article is intended to generate an understanding of the flow mechanics of the vena contracta and the sonographic technique required to provide consistent and accurate measurements of vena contracta width in patients with mitral regurgitation.

Vena contracta width measurement: theoretic basis and usefulness in the assessment of valvular regurgitation severity

In patients with valvular regurgitation, the regurgitation jet can be observed by Doppler color flow imaging. Vena contracta is defined as the narrowest part of the jet, just distal to the regurgitant orifice. Vena contracta dimensions reflect the severity of regurgitation. Vena contracta diameter, usually easy to measure in clinical practice, is well correlated with the effective regurgitant orifice area and the regurgitant volume. Cutoff values have been determined to identify severe regurgitation for mitral, aortic, and tricuspid valves. In clinical practice, determination of vena contracta diameter is a useful and simple method for assessment of valvular regurgitation. In the future, assessment of complex jet regurgitations will probably benefit from the contribution of three-dimensional Doppler flow imaging, which should improve the performances of the method.

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.

Detection of mechanisms of immediate failure by transesophageal echocardiography in quadrangular resection mitral valve repair technique for severe mitral regurgitation

Residual mitral regurgitation (MR) after repair is a risk factor for late reoperation. The use of intraoperative transesophageal echocardiography (IOTEE) decreases the incidence of immediate repair failure. This study identifies the mechanisms of immediate failure by IOTEE in the quadrangular resection technique, a well-standardized mitral valve repair procedure to guide further repair procedures. Two hundred five consecutive patients underwent quadrangular resection due to prolapse or flail posterior leaflet. Twenty-four patients (11%) had immediate failure. Immediate reinstitution of cardiopulmonary bypass ("second pump run") was needed in 21 patients (10%) for further repair. The identified mechanisms of failure were residual cleft provoking interscallop malcoaptation into the posterior leaflet in 8 patients, residual prolapse of the anterior or posterior leaflets in 1 and 4 patients, respectively, residual annular dilation in 3, left ventricular outflow obstruction in 2, suture dehiscence in 2, and other mechanisms in another 2 patients. In 20 patients (95%), IOTEE guided further repair with resolution of the residual MR, whereas 1 patient underwent valve replacement due to pharmacologically untreatable left ventricular outflow obstruction. In conclusion, even if this type of valve repair technique is well standardized, the incidence of immediate failure is not negligible. IOTEE identified the mechanisms of the immediate failure and guided further repair procedures, thus reducing the incidence of valve replacement (0.5%) without increasing perioperative mortality and morbility.

Evaluación de la severidad y decisiones quirúrgicas en las valvulopatías

A better knowledge of the natural history of valvular disease and the advances in surgical techniques are allowing to improve the prognosis of patients with valvular heart disease. At present, imaging techniques, particularly Doppler-echocardiography, is the main tool to determine the diagnosis and prognosis of patients with valvular heart disease. Consequently, decision making in valvular heart disease is now days based on a combination of symptomatic status and echocardiographic findings. The main applications of Doppler-echocardiography with this purpose are summarized in this article. Therapeutic algorithms for patients with valvular heart disease are proposed, as well as the potential application of new imaging modalities appeared in the last years. The state of the art of clinical practice guidelines are also reviewed.

Echocardiographic evaluation of mitral regurgitation

Accurate evaluation of mitral regurgitation (MR) severity remains a challenging task in clinical cardiology. The importance of proper quantification of regurgitation cannot be underestimated because a delayed decision to replace or repair a defective valve may lead to worsening ventricular function and increased perioperative and long-term mortality. In this review we discuss both recent developments in the quantification of MR as well as new insights into the pathophysiology and progression of this lesion.

Magnetic resonance planimetry of the vena contracta as a new approach to assessment of stenotic heart valves: an in vitro study

Exact determination of the orifice area in stenotic valve disease is essential to guide therapy. With the standard imaging methods, the orifice area has to be calculated by empirically-derived formulas, which may be susceptible to changes in hemodynamic status, leading to wrong therapeutic decisions. We tested the ability of magnetic resonance imaging (MRI) to quantify the orifice area by planimetry of the proximal vena contracta (PVC) in an idealized, constant-flow model in a 1.0-T tomograph (Siemens Magnetom Expert). There was a close correlation of the PVC area in MRI and the true orifice area (r2 = 0.985), and agreement of the methods as measured by the Bland-Altman test was significant with a low systematic error of -0.02 cm2. We conclude that MRI planimetry of the PVC in stenotic valves in a constant-flow model may be used to reliably measure the orifice area.

Assessment of aortic regurgitation by transesophageal color Doppler imaging of the vena contracta: validation against an intraoperative aortic flow probe

OBJECTIVES

This study was performed to validate the accuracy of color flow vena contracta (VC) measurements of aortic regurgitation (AR) severity by comparing them to simultaneous intraoperative flow probe measurements of regurgitant fraction (RgF) and regurgitant volume (RgV).

BACKGROUND

Color Doppler imaging of the vena contracta has emerged as a simple and reliable measure of the severity of valvular regurgitation. This study evaluated the accuracy of VC imaging of AR by transesophageal echocardiography (TEE).

METHODS

A transit-time flow probe was placed on the ascending aorta during cardiac surgery in 24 patients with AR. The flow probe was used to measure RgF and RgV simultaneously during VC imaging by TEE. Flow probe and VC imaging were interpreted separately and in blinded fashion.

RESULTS

A good correlation was found between VC width and RgF (r = 0.85) and RgV (r = 0.79). All six patients with VC width >6 mm had a RgF >0.50. All 18 patients with VC width <5 mm had a RgF <0.50. Vena contracta area also correlated well with both RgF (r = 0.81) and RgV (r = 0.84). All six patients with VC area >7.5 mm2 had a RgF >0.50, and all 18 patients with a VC area <7.5 mm2 had a RgF <0.50. In a subset of nine patients who underwent afterload manipulation to increase diastolic blood pressure, RgV increased significantly (34 +/- 26 ml to 41 +/- 27 ml, p = 0.042) while VC width remained unchanged (5.4 +/- 2.8 mm to 5.4 +/- 2.8 mm, p = 0.41).

CONCLUSIONS

Vena contracta imaging by TEE color flow mapping is an accurate marker of AR severity. Vena contracta width and VC area correlate well with RgF and RgV obtained by intraoperative flow probe. Vena contracta width appears to be less afterload-dependent than RgV.

Transesophageal echocardiographic (TEE) evaluation of the mitral and tricuspid valves

In skilled hands, multiplane TEE provides a comprehensive assessment of the anatomy and function of the mitral and tricuspid valves. TEE is uniquely effective in the evaluation of the diverse pathophysiologic processes that cause valvular heart disease.

Effects of afterload reduction on vena contracta width in mitral regurgitation

OBJECTIVES

We used color Doppler flow mapping to determine whether vena contracta width (VCW) is a load-independent measure of the severity of mitral regurgitation.

BACKGROUND

VCW has been proposed to be a relatively load-independent measure of mitral regurgitation severity in flow models using a fixed orifice. However, in patients with mitral regurgitation, VCW may not be load independent because of a dynamic regurgitant orifice.

METHODS

VCW, effective regurgitant orifice area and regurgitant volume were measured by quantitative Doppler mapping in 31 patients with chronic mitral regurgitation at baseline and during nitroprusside infusion. Patients with rheumatic heart disease, annular calcification or endocarditis were considered to have a fixed regurgitant orifice, whereas patients with mitral valve prolapse, dilated cardiomyopathy or ischemia were considered to have a dynamic regurgitant orifice.

RESULTS

Systolic blood pressure (148 +/- 27 to 115 +/- 25 mm Hg) and end-systolic wall stress (121 +/- 50 to 89 +/- 36) decreased with nitroprusside (p < 0.05). Although nitroprusside did not significantly change mean values for VCW (0.5 +/- 0.2 to 0.5 +/- 0.2 cm), regurgitant volume (69 +/- 47 to 69 +/- 56 ml) or effective regurgitant orifice area (0.5 +/- 0.4 to 0.5 +/- 0.6 cm2), individual patients exhibited marked directional variability. Specifically, VCW decreased in 16 patients (improved mitral regurgitation), remained unchanged in 7 patients and increased in 8 patients (worsened mitral regurgitation) with nitroprusside. Also, the VCW response to nitroprusside was concordant with changes in effective regurgitant orifice area and regurgitant volume, and was not different between dynamic and fixed orifice groups.

CONCLUSIONS

Contrary to the results from in vitro studies, VCW is not load independent in patients with mitral regurgitation caused by dynamic changes in the regurgitant orifice. The origin of mitral regurgitation does not predict accurately whether the regurgitant orifice is fixed or dynamic. Finally, short-term vasodilation with nitroprusside may significantly worsen the severity of mitral regurgitation in some patients.