A technology based on velocity ratio indices is described for application in the myocardium. Angle-independent Doppler indices, such as the pulsatility index, which employ velocity ratios, can be measured even if the ultrasound beam vector at the moving target and the motion vector are not in a known plane. The unknown plane situation is often encountered when an ultrasound beam interrogates sites in the myocardium. The velocities employed in an index calculation must be close to the same or opposite directions. The Doppler velocity ratio indices are independent of angle in 3D space as are ratio indices based on 1D strain and 1D speckle tracking. Angle-independent results with spectral Doppler methods are discussed. Possible future imaging techniques based on velocity ratios are presented. By using indices that involve ratios, several other sources of error cancel in addition to that of angular dependence for example errors due to less than optimum gain settings and beam distortion. This makes the indices reliable as research or clinical tools. Ratio techniques can be readily implemented with current commercial blood flow pulsed wave duplex Doppler equipment or with pulsed wave tissue Doppler equipment. In 70 patients where the quality of the real-time B-mode looked suitable for the Doppler velocity ratio technique, there was only one case where clear spectra could not be obtained for both the LV wall and the septum. A reproducibility study of spectra from the septum of the heart shows a 12% difference in velocity ratios in the repeat measurements.
Norman McDicken, Adrian Thomson, Audrey White, Iqbal Toor, Gillian Gray, Carmel Moran, Robin J Watson and Tom Anderson
Ewa A Konik, Merri Bremer, Peter T Lin and Sorin V Pislaru
A 67-year-old man with myelodysplastic syndrome, disseminated histoplasmosis, and mitral valve replacement presented with dyspnea and peripheral edema. Transthoracic echocardiography demonstrated abnormal pulmonic valve with possible vegetation. Color flow imaging showed laminar flow from main pulmonary artery into right ventricular outflow tract (RVOT) in diastole. The continuous wave Doppler signal showed dense diastolic envelope with steep deceleration slope. These findings were consistent with severe pulmonic valve regurgitation, possibly due to endocarditis. Transesophageal echocardiography demonstrated an echodense mass attached to the pulmonic valve. The mitral valve bioprosthesis appeared intact. Bacterial and fungal blood cultures were negative; however, serum histoplasma antigen was positive. At surgery, the valve appeared destroyed by vegetations. Gomori methenamine silver-stains showed invasive fungal hyphae and yeast consistent with a dimorphic fungus. Valve cultures grew one colony of filamentous fungus. Itraconazole was continued based on expert infectious diseases diagnosis. After surgery, dyspnea and ankle edema resolved. To the best of our knowledge, histoplasma endocarditis of pulmonic valve has not been previously reported. Isolated pulmonic valve endocarditis is rare, accounting for about 2% of infectious endocarditis (IE) cases. Fungi account for about 3% of cases of native valve endocarditis. Characterization of pulmonary valve requires thorough interrogation with 2D and Doppler echocardiography techniques. Parasternal RVOT view allowed visualization of the pulmonary valve and assessment of regurgitation severity. As an anterior structure, it may be difficult to image with transesophageal echocardiography. Mid-esophageal right ventricular inflow–outflow view clearly showed the pulmonary valve and vegetation.
- Identification and characterization of pulmonary valve abnormalities require thorough interrogation with 2D and Doppler echocardiography techniques.
- Isolated pulmonary valve IE is rare and requires high index of suspicion.
- Histoplasma capsulatum IE is rare and requires high index of suspicion.
Garvan C Kane, Arun Sachdev, Hector R Villarraga, Naser M Ammash, Jae K Oh, Michael D McGoon, Patricia A Pellikka and Robert B McCully
It is not well known if advancing age influences normal rest or exercise pulmonary artery pressures. The purpose of the study was to evaluate the association of increasing age with measurements of pulmonary artery systolic pressure at rest and with exercise.
Subjects and methods
A total of 467 adults without cardiopulmonary disease and normal exercise capacity (age range: 18–85 years) underwent symptom-limited treadmill exercise testing with Doppler measurement of rest and exercise pulmonary artery systolic pressure.
There was a progressive increase in rest and exercise pulmonary artery pressures with increasing age. Pulmonary artery systolic pressures at rest and with exercise were 25±5mmHg and 33±9mmHg, respectively, in those <40 years, and 30±5mmHg and 41±12mmHg, respectively, in those ≥70 years. While elevated left-sided cardiac filling pressures were excluded by protocol design, markers of arterial stiffness associated with the age-dependent effects on pulmonary pressures.
These data demonstrate that in echocardiographically normal adults, pulmonary artery systolic pressure increases with advancing age. This increase is seen at rest and with exercise. These increases in pulmonary pressure occur in association with decreasing transpulmonary flow and increases in systemic pulse pressure, suggesting that age-associated blood vessel stiffening may contribute to these differences in pulmonary artery systolic pressure.
Miriam Shanks, Lucas Valtuille, Jonathan B Choy and Harald Becher
Various Doppler-derived parameters of left atrial electrical remodeling have been demonstrated to predict recurrence of atrial fibrillation (AF) after AF ablation. The aim of this study was to compare three Doppler-derived measures of atrial conduction time in patients undergoing AF ablation, and to investigate their predictive value for successful procedure. In 32 prospectively enrolled patients undergoing the first AF ablation, atrial conduction time was estimated by measuring the time delay between the onset of P-wave on the surface ECG to the peak of the a′-wave on the pulsed-wave Doppler and color-coded tissue Doppler imaging of the left atrial lateral wall, and to the peak of the A-wave on the pulsed-wave Doppler of the mitral inflow. There was a significant difference in the baseline atrial conduction time measured by different echocardiographic techniques. Most (88%) patients had normal or only mildly dilated left atrium. At 6 months, 12 patients (38%) had recurrent AF/atrial tachycardia. The duration of history of AF was the only predictor of AF/atrial tachycardia recurrence following the first AF ablation (P=0.024; OR 1.023, CI 1.003–1.044). A combination of normal left atrial volume and history of paroxysmal AF of ≤48 months was associated with the best outcome. Predictive value of the Doppler derived parameters of atrial conduction time may be reduced in the early stages of left atrial remodeling. Future studies may determine which echocardiographic parameter correlates best with the extent of left atrial remodeling and is most predictive of successful AF ablation.
Dimitris Klettas, Emma Alcock, Rafal Dworakowski, Philip MacCarthy and Mark Monaghan
The role of transoesophageal echocardiography in cardiac interventional structural procedures is well established and appreciated. However, the need for general anaesthesia (GA) throughout the procedure remains a controversial issue. The aim of the present study is to assess the feasibility and imaging quality of using a transnasal microrobe that allows the usage of conscious sedation in patients who undergo cardiac structural interventional procedures without missing the benefits, guidance and navigation of conventional trans-procedural TEE.
We analysed the trans-procedural images of 24 consecutive patients who underwent TAVI, TMVI or ASD/PFO closure, using a transnasal 2D microprobe (PHILIPS) and then we compared them with images taken by using a conventional 3D TEE probe (PHILIPS). In particular, we compared the imaging quality of the two probes regarding: (1) The anatomy, visualisation of valvular calcification and transvalvular colour Doppler of the aortic and mitral valve; (2) the imaging quality of PFO, ASD and interatrial communication colour flow; (3) the imaging of left ventricle systolic function and pericardial space and (4) transgastric imaging.
All images were graded with a scale from 5 to 1. The average grade of imaging quality in the mitral valve was: anatomy, 4.3; calcification, 3.8; colour Doppler, 4.2. The average grade of imaging quality in the aortic valve was: anatomy, 4.3; calcification, 3.7; colour Doppler, 4.3. The average grade of imaging quality in PFO/ASD was 4.3. The average grade of imaging quality in LV/pericardial space was 4.2. The average grade of imaging quality in transgastric imaging was 4.1.
These results suggest that transnasal TEE can provide good anatomical image quality of relevant cardiac structures during cardiac structural interventions and this may facilitate these procedures being performed during conscious sedation without having to lose TEE guidance.
Stephan Stoebe, Dietrich Pfeiffer and Andreas Hagendorff
The aim of this study was to test the feasibility of the visualisation of 3D4D coronary flow in detectable segments of coronary arteries. Regarding the feasibility of this new approach, the hypothesis was proposed that the flow signals of the course of detectable coronary arteries can be better visualised by 3D4D echocardiography than by the conventional 2D approach. A total of 30 consecutive patients with sinus rhythm, in whom the distal left anterior descending artery (LAD) was visualised by 2D colour-coded Doppler echocardiography, were selected for 3D4D scanning procedures. All measurements were performed using a Vivid 7 or E9. All segments visualised by 2D colour-coded Doppler echocardiography were also examined by 3D4D echocardiography. Using defined settings, the width of the colour-coded flow signal differs significantly between 2D- and 3D4D echocardiography. The length of larger segments of the visualised colour-coded flow signal of the coronary flow could be better detected with 2D imaging. Small segments of coronary artery flow (<11 mm), however, could be significantly better visualised by 3D4D echocardiography. The main advantage of 3D4D echocardiography of the coronary artery flow is the visualisation of the proportions of vessels with complex morphology. 3D4D echocardiography of LAD flow by colour-coded Doppler echocardiography raises new possibilities for the direct flow visualisation of the detectable segments of coronaries. With its sufficiently high spatial and temporal resolution, this new method has the potential to be implemented in clinical scenarios. The possible application to the quantification of stenoses by the flow visualisation has to be evaluated in further studies.
Charles L Brassard, Claudia Viens, André Denault and Pierre Couture
We present a case of mitral valve (MV) replacement that resulted in multiple complications, as diagnosed by transesophageal echocardiography (TEE), including left ventricular outflow tract obstruction, aortic dissection and left ventricular rupture. We also describe that identification of bleeding originating from the posterior aspect of the heart by the surgical team should trigger a complete TEE evaluation for adequate diagnosis. An 84-year-old woman underwent a MV replacement. Weaning from cardiopulmonary bypass (CPB) revealed a late-peaking gradient of 44 mmHg over the left ventricular outflow tract caused by obstruction from a bioprosthetic strut. After proper surgical correction, TEE evaluation showed a type A aortic dissection that was subsequently repaired. After separation from CPB, the surgical team identified a major bleed that originated from the posterior aspect of the heart. Although the initial suspicion was injury to the atrioventricular groove, a complete TEE evaluation confirmed a left ventricular free wall rupture by showing the dissecting jet using colour-flow Doppler. TEE is an essential component in cardiac surgery for assessment of surgical repair and potential complications. Posterior bleeding should trigger a complete TEE examination with assessment of nearby structures to rule out a life-threatening pathology. Left ventricular free wall rupture can be identified using colour-flow Doppler.
- Multiple complications may occur after MVR.
- TEE is an essential component in the evaluation of surgical repair and its potential associated complications, including LVOT obstruction, aortic dissection and LV rupture.
- Posterior bleeding, from the region of AV groove, should trigger a complete TEE examination with assessment of nearby structures such as the atria, coronary sinus and myocardium to rule out a life threatening pathology.
- The diagnosis of a LV rupture can be confirmed with 2-D imaging and colour-flow Doppler demonstrating a dissecting jet through the myocardium.
Emily Worley, Bushra Rana, Lynne Williams and Shaun Robinson
The left atrium (LA) is exposed to left ventricular pressure during diastole. Applying the 2016 American Society of Echocardiography left ventricular diastolic function (LVDF) guidelines, this study aims to investigate whether left atrial ejection fraction (LAEF) and left atrial active emptying fraction (LAAEF) are markers of diastolic dysfunction (LVDD).
Retrospective cohort of consecutive patients (n = 124) who underwent transthoracic echocardiography were studied. Doppler peak velocities of passive (MV E) and active filling (MV A) were measured and ratio E/A calculated. Tissue Doppler imaging parameters of peak early (e′) of the septal and lateral mitral annulus were measured, and average E/e′ ratio (E/e′) was calculated. Tricuspid regurgitation velocity, left atrial maximum volume, left atrial minimum volume and LA volume pre-contraction were measured, allowing calculation of LAEF and LAAEF. Subjects were assigned LVDF categories.
Binomial logistic regression model (X 2(2) = 48.924, P < 0.01) determined that LAEF and LAAEF predicted diastolic dysfunction with sensitivity 85.5% and specificity 78%. ROC curves determined good diagnostic accuracy for LAEF and LAAEF to predict LVDD, AUC 0.826 and 0.861 respectively. Logistic regression model (X 2(2) = 39.525, P < 0.01) predicted those patients with E/e′ ≥14 using LAEF and LAAEF with sensitivity 51.6% and specificity 92.4%. Moderate correlations were found between E/e′ and log derivatives of LAEF and LAAEF.
A decline in LAAEF and LAEF is associated with worsening LVDD.
The advancement of echocardiography in the past two decades is more than downsizing of the machines and improvement of image quality, but introduction of new imaging modalities leading to the ability of performing quantitative analysis. This function is greatly facilitated by the integration of echo machines with high performance computers, software programming and establishment of workstation for offline analysis. Today, echo examination is more than estimation of ejection fraction (EF) and patterns of left ventricular (LV) diastolic dysfunction. Echosonographers are facing a large number of quantitative parameters for interpretation. In newer imaging modalities such as tissue Doppler imaging, speckle tracking, 3-dimensional echocardiography and 3D-transoesophageal echocardiography, quantitative echocardiographic assessment has important roles. These have brought many opportunities but also challenges in our echo practice.
Malgorzata Wamil, Sacha Bull and James Newton
Despite significant advancements in the field of cardiovascular imaging, transoesophageal echocardiography remains the key imaging modality in the management of valvular pathologies. This paper provides echocardiographers with an overview of the modern role of TOE in the diagnosis and management of valvular disease. We describe how the introduction of 3D techniques has changed the detection and grading of valvular pathologies and concentrate on its role as a monitoring tool in interventional cardiology. In addition, we focus on the echocardiographic and Doppler techniques used in the assessment of prosthetic valves and provide guidance for the evaluation of prosthetic valves. Finally, we summarise quantitative methods used for the assessment of valvular stenosis and regurgitation and highlight the key areas where echocardiography remains superior over other novel imaging modalities.