Jiefen Yao

Variation of anatomic valve area during ejection in patients with valvular aortic stenosis evaluated by two-dimensional echocardiographic planimetry: comparison with traditional Doppler data ☆

OBJECTIVES Flow variations can affect valve-area calculation in aortic stenosis and lead to inaccuracies in the evaluation of the stenosis. Knowing that transvalvular flow varies normally within one beat, we designed this study to assess the response of the valve to intrabeat variation of flow during systole. Results were compared with flow-derived measurements. BACKGROUND Technological improvements now allow us to evaluate aortic valve area directly by short axis planimetry. This offers the possibility to perform serial planimetries during one ejection phase and analyze the intrabeat dynamic behavior of the stenotic-aortic valve and compare these measurements with flow-derived measurements. METHODS Forty echocardiograms displaying different degrees of aortic stenosis were analyzed by frame-by-frame planimetry of the valve area from onset of opening to complete closure. Maximal-mean area, opening and closing rates and ejection times were obtained and compared with Doppler-derived data. RESULTS Valve area varied during ejection. Stenotic valves opened and closed more slowly than normals and remained maximally open for a shorter period. Mean area by Doppler data corresponded more closely to maximal than to mean-planimetered area. Duration of flow was shorter than valve opening in severely stenotic valves. Discrepancies between Doppler-derived and two-dimensional (2D) measurements decreased in less stenotic valves. CONCLUSIONS Our observations reveal striking differences between the dynamics of normal and stenotic valves. Surprisingly, Doppler-derived mean-valve area correlated better with maximal-anatomic area than with mean-anatomic area in patients with aortic stenosis. Discrepancies between duration of flow and valve opening could explain this phenomenon.

Three-Dimensional Echocardiographic Estimation of Infarct Mass Based on Quantification of Dysfunctional Left Ventricular Mass

BACKGROUND Two-dimensional echocardiography is useful for estimating the extent of infarct-related wall motion abnormalities. Such estimation, however, is based on a few selected views and extrapolated for the whole left ventricle (LV). This approach does not provide us with the actual amount of dysfunctional myocardium. Volume-rendered three-dimensional echocardiography (3DE) might overcome these limitations. In this study we explored (1) how well volume-rendered 3DE delineates regional dysfunction of the infarcted LV and (2) how well dysfunctional myocardial mass quantified by 3DE reflects the actual anatomic infarct mass. METHODS AND RESULTS 3DE was performed before and 3 hours after coronary occlusion in 16 dogs. With the LV viewed in equidistant short-axis slices, the region of dysfunction was demarcated, and the dysfunctional myocardial mass was derived from this. With triphenyltetrazolium chloride staining, anatomic infarct regions were delineated, dissected, and weighed. The anatomic infarct mass was 16.3+/-7.7 g (mean+/-SD) (range, 6.4 to 31.4 g); the dysfunctional mass estimated by 3DE was 17.4+/-9.1 g (range, 5.2 to 39.0 g). The mean difference was 1.0 g. The correlation between dysfunctional mass (y) and infarct mass (x) was y=l.lx-0.6, r=.93 (P<.0001). The percentage of LV involved in infarction was 18.2+/-5.8% (range, 9.1% to 26.1%); the percentage of LV involved in regional dysfunction was 18.3+/-6.9% (range, 7.9% to 31.2%). The mean difference was 0.1%. The correlation between percentage of LV involved in infarction (x) and percentage of LV involved in dysfunction (y) was y=1.0x-1.1, r=.92 (P<.0001). CONCLUSIONS Volume-rendered 3DE crisply displays regional dysfunction of infarcted LV. 3DE-measured dysfunctional mass accurately reflects the anatomic infarct mass.

Diagnostic Accuracy of Transthoracic and Multiplane Transesophageal Echocardiography for Valvular Perforation in Acute Infective Endocarditis: Correlation with Anatomic Findings

We evaluated the diagnostic accuracy of transthoracic and multiplane transesophageal echocardiography (TTE and TEE, respectively) for assessing valvular perforation during active infective endocarditis by correlating the results of TTE and TEE with anatomic findings of 88 valves examined at surgery or autopsy. Compared with TEE, TTE has a low diagnostic sensitivity in the detection of this complication and, in the presence of hemodynamic instability, multiplane TEE should be performed directly.

Clinical application of transthoracic volume-rendered three-dimensional echocardiography in the assessment of mitral regurgitation

Two-dimensional echocardiography (2-DE) and Doppler methods are generally used for assessing mechanisms and severity of mitral regurgitation (MR). Recently, 3-dimensional echocardiography (3-DE) has been applied successfully in various cardiac disorders, but its value in evaluating the mechanism and the severity of MR are not known. We studied 30 patients with MR using 2-DE and 3-DE. Volume-rendered gray-scale 3-DE images of the mitral valve apparatus and MR jets were reconstructed. Maximal volume of the MR jet by 3-DE was compared with mitral regurgitant volume and fraction, regurgitant jet area and the ratio of jet area to left atrial area, and semiquantitative grading derived from 2-DE methods. Our results demonstrated that 3-DE aided in a better depiction of the mitral apparatus and its abnormalities in 70% of the patients. The origin, direction, and morphology of the MR jet were better delineated in 3-DE volumetric display. Quantitative analysis, however, showed only a weak to moderate correlation between 3-DE maximal MR jet volume and 2-DE mitral regurgitant volume (y = 0.5x + 11.4, r = 0.7), regurgitant fraction (y = 0.5x + 8.2, r = 0.65), mitral regurgitant jet area (y = 0.2x + 5, r = 0.51), jet area to left atrial area ratio (y = 0.53x + 7.6, r = 0.54), and semiquantitative grading of MR (y = 9.1x - 1.8, r = 0.74). In conclusion, 3-DE aids in a better understanding of the mechanisms of MR and morphology of the regurgitant jets. Its quantitative ability, when reconstruction of the jet alone is used, may be limited.

Three-dimensional echocardiography: clinical relevance and application

Three-dimensional (3D) echocardiography has recently become a practical reality. It is now practicable to perform 3D echocardiography using transthoracic and transesophageal acoustic windows both in adults and children. The unique image projections that 3D echocardiography yields appear to have enormous potential for displaying intracardiac anatomy in exquisite detail. An important aspect of 3D echocardiography is its ability to supply accurate quantitative data without the use of geometric assumptions. In particular, coupled to contrast ultrasound agents, 3D echocardiography could be valuable in the assessment of myocardial perfusion abnormalities. Early clinical experience suggests that 3D echocardiography is likely to play a valuable role in the evaluation of various cardiac disorders, especially in cardiac surgery. In this section, we will review the use of volume-rendered 3D echocardiography in the diagnosis and assessment of cardiac disorders with particular emphasis on the clinical application of this new methodology.

Mitral Regurgitation: Comprehensive Assessment by Echocardiography

Two‐dimensional and Doppler echocardiography have become the major modalities for the assessment of mitral regurgitation. The combined use of these techniques provides information regarding the morphology of the valvular apparatus as well as the severity of regurgitation. Transesophageal and three‐dimensional echocardiography provide a more‐detailed evaluation of valve morphology, which can be valuable in determining suitability for valve repair. In patients with severe mitral regurgitation, echocardiographic assessment of ventricular size and function plays a critical role in determining the optimal timing of surgery.

Determination of left ventricular mass by three-dimensional echocardiography: In vitro validation of a novel quantification method using multiple equi-angular rotational planes for rapid measurements

Measuring left ventricular mass by m-mode echocardiography or two-dimensional echocardiography is limited by the fact that calculations are based on assumptions, which describe left ventricular shape by simple geometric figures. The ability of three-dimensional echocardiography (3-DE) to accurately assess left ventricular mass has been shown previously, but 3-DE approaches to quantitative analysis of ventricular mass required multiple tomographic sectioning, manual tracing in various cut planes and were time consuming and laborious. We investigated the accuracy of a novel, rapid method of 3-DE mass quantification using multiple rotational planes in left ventricles in vitro. Methods: Three-dimensional data sets of 10 fixed pig hearts were obtained using a TomTec 3-DE system. For 3-DE mass calculations, a rotational axis in the center of the ventricle (apical–basal orientation) was defined and 3, 6 and 12 equi-angular rotational planes were created. The endocardial and epicardial contour of the left ventricle was traced in each cut plane and the volume of the corresponding myocardial wedge was automatically calculated. Mass was calculated by multiplying the resulting myocardial volume by the specific weight of myocardial tissue. The measurements were performed by two investigators blinded to the anatomic true mass and were analyzed for interobserver and intraobserver variability. Results: The anatomic left ventricular mass was measured 73–219 (168 ± 50) g. 3-DE mass ranged from 88–247 (207 ± 51) g (three planes), 84–250 (205 ± 52) g (six planes) and 86–241 (202 ± 50) g (12 planes) respectively. The correlation between 3-DE mass and anatomic LV mass measurements (r = 0.92) and between two observers (r = 0.97–0.98) was good. True mass was slightly overestimated by 3-DE measurement (SEE = 22–23 g). The intraobserver and interobserver variabilities were ≤4 and ≤7% respectively for all measurements. Conclusion: This new 3-DE method of left ventricular mass quantification with rotational approach provides accurate and reproducible measurements. In normal shaped left ventricles even three planes were sufficient to provide accurate mass measurements in vitro.

Three-Dimensional Transesophageal Echocardiography (TEE) and Other Future Directions

As faster imaging systems enter the market, three-dimensional echocardiography is gearing up to become a useful tool in assisting the clinician to image the heart in many innovative projections. What started out as a novel idea of displaying a three-dimensional anatomic picture of the heart now provides a multitude of views of the heart and its structures. Information gained from anatomic and dynamic data has helped clinicians and surgeons in making clinical decisions. In the future, this imaging modality may become a routine imaging modality for assessing cardiac pathology and may serve to increase understanding of the dynamics of the heart.

A Head‐to‐Head Comparison of Infusion and Bolus Doses of Adenosine for Stress Myocardial Contrast Echocardiography

Background: This study was a head‐to‐head, intraindividual comparison of the diagnostic accuracy and side effect profile of bolus and infusion administration of adenosine for stress myocardial contrast echocardiography (MCE). Methods: Adenosine MCE was performed in 64 subjects, referred for stress thallium‐201 single‐photon emission computed tomography (SPECT) for known or suspected CAD. Each patient received adenosine by multiple boluses (6–12 mg/bolus) and infusion (140 μg/kg per min for 6 min) forms in random order, given at least 20 minutes apart. Results: No prolonged or serious adverse events occurred during either adenosine bolus or infusion. Compared to SPECT imaging, the sensitivity, specificity, and concordance for the diagnosis of CAD were 77%, 87%, and 82% for adenosine infusion MCE and 81%, 90%, and 86% for adenosine bolus MCE, respectively. Conclusions: Both adenosine infusion and adenosine bolus protocols are safe for MCE in humans and can be used for the diagnosis of CAD.

Identification of Viable Myocardium by Perfusion Imaging with Intravenous Contrast Echocardiography After Acute Myocardial Infarction

Myocardial perfusion contrast echocardiography is evolving into an effective method for the evaluation of myocardial blood flow after acute coronary events. The direct injection of ultrasound contrast agents into the aortic and coronary circulation has been shown to accurately identify areas of viable myocardial tissue. Recently, intravenous ultrasound contrast has been found to be useful in detecting microvascular blood flow after the restoration of blood flow in patients with myocardial infarction. We present the case of a patient in whom intravenous ultrasound contrast assisted in the detection of viable myocardial tissue after an acute ischemic syndrome.