Color Doppler Echocardiography

Color Doppler echocardiography assesses blood flow based on changes in the ultrasonographic signal due to the movement of erythrocytes relative to the transducer.

From: Pulmonary Vascular Disease , 2006

Aortic Regurgitation

Catherine M. Otto MD , in Practice of Clinical Echocardiography , 2022

Color Doppler Echocardiography

Color Doppler echocardiography is the key method for the diagnosis and quantification of AR in clinical practice. 16 The regurgitant color Doppler flow pattern has three components: the proximal flow convergence or proximal isovelocity surface area (PISA), the vena contracta, and the distal jet. 16 Color jet area correlates only weakly with the degree of AR, mainly in cases of acute or subacute AR that are particularly affected by the aortic-to-LV diastolic pressure gradient and LV compliance. 17

Despite the limitations, the difference between mild and significant chronic AR may be estimated whenever the same instrument settings are employed and complete visualization of the jet extension using different apical projections is used 23 (Fig. 23.3). In our experience, 18 in cases of chronic AR, a jet area of less than 4 cm2 or more than 7 cm2 was specific for mild or significant regurgitation, respectively. However, because of high intermachine variations, 18 , 19 the use of color flow area of the regurgitant jet is not recommended and should be used only for a visual assessment of AR.

Semiquantitative Methods

Vena contracta width is one of the best methods for grading AR severity. 16 The vena contracta represents the smallest flow diameter at the aortic valve level, immediately below the flow convergence region. The vena contracta is measured in the parasternal long-axis view (Fig. 23.4). A narrow color sector scan and zoom mode are recommended to optimize this measurement. Using a Nyquist limit of 50 to 60 cm/s, a vena contracta width of less than 3 mm correlates with mild AR, whereas a width greater than 6 mm indicates severe AR. 20

The vena contracta method is limited when the regurgitant orifice is elliptical or irregular. 3D echocardiography permits better vision and analysis of the real vena contracta (Fig. 23.5). With 3D echocardiography, vena contracta areas smaller than 20 cm2 and larger than 60 cm2 have been proposed to define mild and severe AR, respectively. 21

Proximal regurgitant jet width and its ratio to LVOT diameter are obtained from the long-axis views measured immediately below the aortic valve (at the junction of the LVOT and the aortic annulus). A ratio of less than 25% is consistent with mild AR, whereas a ratio greater than 65% indicates severe AR. 22 However, the absolute value of the jet width has similar accuracy and better reproducibility than this ratio, indicating that jet width alone may be sufficient and more practical for follow-up of patients. A jet width greater than 10 mm indicates severe AR, and one less than 7 mm indicates nonsignificant AR 18 (seeFig. 23.4).

Arterio-venous Fistulas and Related Conditions

Shakeel A. Qureshi , John F. Reidy , in Paediatric Cardiology (Third Edition), 2010

Investigations

The electrocardiogram shows left ventricular hypertrophy in the majority of patients. Cross sectional and colour Doppler echocardiography usually confirms the diagnosis. In the occasional patient in whom the diagnosis is difficult, magnetic resonance imaging or cardiac catheterisation may be helpful.97 Angiography in the aortic root usually confirms the diagnosis, although this should be rarely required nowadays. There may be gross dilation and distortion of the aortic sinus, ascending aorta, and the left ventricle. Angiography may also show normal origin of the coronary arteries, thus differentiating the tunnel from a fistula from the coronary artery to the left ventricle. The anterior location of the abnormal tunnel, and the demonstration of a normal aortic sinus of Valsalva, distinguishes the tunnel from ruptured aneurysm of a sinus of Valsalva into the left ventricle.

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Percutaneous balloon mitral valvuloplasty and mitral valve repair

BERNARD D. PRENDERGAST , ... ALEC VAHANIAN , in Essential Interventional Cardiology (Second Edition), 2008

Anatomical aspects

The evaluation of candidates for the procedure requires a precise assessment of valve morphology and function for advance planning of balloon dilatation and subsequent follow-up. Subsequent to clinical examination, two-dimensional colour Doppler echocardiography is currently the best and most widely used non-invasive technique for assessing the suitability of the mitral valve for balloon dilatation, allowing evaluation of the anatomical characteristics of the valve and subvalvular apparatus, and the size of the valve annulus (Table 31.1).

In rheumatic mitral stenosis the valve leaflets are characteristically thickened (and often calcified) at echocardiography with evidence of commissural fusion. The degree of commissural fusion is usually best assessed using transthoracic echocardiography in the parasternal short axis view. Cusp mobility is reduced and bowing of the leaflets occurs in diastole. Associated features such as left atrial enlargement and/or thrombus, pulmonary hypertension and mitral regurgitation may also be apparent. Transthoracic imaging is satisfactory in most patients, but the valve is better defined by transoesophageal imaging. The aims of echocardiographic assessment prior to balloon valvuloplasty are to identify features predictive of a poor outcome, such as extensive valvular calcification, marked thickening and scarring of the subvalvular apparatus and the presence of associated mitral regurgitation. In addition, it is important to exclude the presence of left atrial thrombus, which increases the risk of systemic thromboembolism during or following the procedure. Since transoesophageal echocardiography allows more accurate assessment of the degree of leaflet involvement and subvalvular disease and is better at visualising left atrial and appendage thrombus, it is now considered mandatory in all patients prior to balloon valvuloplasty. The presence of thrombus within the left atrium (either floating or localised), particularly on the inter-atrial septum, is a contraindication to balloon valvuloplasty. A number of small series have reported that the procedure is feasible in patients with thrombus restricted to the left atrial appendage, but this remains controversial. Unless there is a need for urgent intervention or anticoagulation is contraindicated for other reasons, the patient can be treated with oral anticoagulants for at least 1 month, after which a follow-up transoesophageal echocardiographic examination often shows disappearance of the thrombus. Spontaneous echo contrast, an echocardiographic marker of blood stasis within the left atrium, is a frequent finding in mitral stenosis and does not prohibit balloon valvuloplasty (Figures 31.1 & 31.2).

The valve area can be assessed using a combination of planimetry of the valve orifice in early diastole and measurement of the pressure half-time (the time interval for the velocity of flow across the valve to fall from its peak value to the peak value divided by the square root of 2, normal <100 ms) from which valve area can be calculated as follows:

Mitral valve area ( cm 2 ) = 220 pressure half - time ( ms )

Generally speaking, it is not advisable to define an arbitrary threshold valve area above which balloon valvuloplasty should not be performed, since overall assessment should also take account of functional disability and the presence of pulmonary hypertension. In practice, however, it is unusual to undertake the procedure in patients with a valve area greater than 1.5 cm2 (or 1 cm2/m2 body surface area if the patient is unusually large).

Coexistent mitral regurgitation can be quantified using Doppler techniques. Severe regurgitation (Sellers grade 3 or 4) contraindicates balloon valvuloplasty whereas mild regurgitation (Sellers grade 1) is acceptable. Patients with moderate mitral regurgitation (Sellers grade 2) present a dilemma and an overall decision should be made in the light of other clinical and echocardiographic variables. In cases where mitral stenosis is combined with severe aortic stenosis, the need for surgery is obvious. Tricuspid regurgitation is usually present to some degree and measurement of the velocity of the jet allows estimation of the pulmonary artery pressure. Reports in relatively small numbers of patients have suggested that balloon valvuloplasty can be performed safely and effectively in patients with severe pulmonary hypertension, though long term outcome may be inferior in this group.

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Pericardial Disease

Peter von Homeyer , in Intraoperative Echocardiography, 2012

Pericardial Cysts and Tumors

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Pericardial cysts are congenital abnormalities but, in some cases, can be acquired after cardiothoracic surgical procedures.

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The typical position is the cardiophrenic angles; they contain water-like fluid and are variable in size.

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These cysts are usually incidental findings, but some patients develop symptoms that are caused by cardiac chamber compression.

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2D echocardiography is the best noninvasive method for diagnosis of pericardial cysts. Color Doppler echocardiography can help to delineate cysts from blood vessels and cardiac chambers.

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Differentiation among pericardial cysts, effusion, and epicardial fat can be challenging in some cases.

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Pericardial tumors are rare. The most common primary tumors are mesotheliomas.

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The diagnosis is often made in advanced disease when tumor compression of cardiac chambers or significant PE is present.

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In this setting, 2D echocardiography can be used to both detect a PE as well as the actual tumor. In some cases, TEE might be more useful depending on the tumor location.

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Cysts and tumors causing clinical symptoms can be treated surgically with a pericardial window or a pericardiectomy.

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Aortic Regurgitation

Issam A. Mikati MD , ... Muhamed Saric MD, PhD , in ASE's Comprehensive Echocardiography (Second Edition), 2016

Role of three-dimensional echocardiography

Current advancements in 3D echocardiography now make it possible not only to visualize the aortic valve anatomy better but also to measure the vena contracta area (Fig. 105.4) and proximal isovelocity surface area without the need for geometric assumptions. 23–25 Recent studies 26, 27 have demonstrated that vena contracta area measurement using 3D color Doppler echocardiography improved quantitation of aortic regurgitation when compared with 2D vena contracta area or conventional echo-Doppler methods when magnetic resonance imaging was used as the gold standard. The difficult challenge of quantitation in case of multiple AR jets can likely be addressed by adding vena contracta areas, similar to the methods shown for multiple jets of mitral regurgitation. 28 Similar to vena contracta, real-time 3D color Doppler PISA methods also improve AR quantitation. 29 Real-time 3D peak and integrated PISA 30 measurement improved quantification of mitral and tricuspid valvular regurgitation when compared with 2D methods, which can be adapted to AR as well. 25 With rapid dissemination of technology, better operator experience, and novel solutions to technological limitations related to 3D echocardiography such as frame rates and stitch artifacts, it is expected that in the very near future, quantitation of AR will be much improved.

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Acute Coronary Syndromes and Acute Myocardial Infarction

Steven Werns , in Critical Care Medicine (Third Edition), 2008

Echocardiography

Echocardiography may be a useful diagnostic tool under a variety of circumstances. A transesophageal echocardiogram may be useful to differentiate STEMI from aortic dissection. Both transthoracic and transesophageal echocardiography are useful in patients with congestive heart failure (CHF) or hypotension to evaluate left and right ventricular function, to rule out cardiac tamponade, and to diagnose ventricular septal rupture or mitral regurgitation (MR). Mitral regurgitation is frequent among patients with uncomplicated MI. Color Doppler echocardiography was performed within 48 hours of admission in a series of 417 consecutive patients with acute MI. 92 Mild mitral regurgitation was present in 121 patients (29%), moderate mitral regurgitation in 21 (5%), and severe mitral regurgitation in 4 (1%). 92 Patients with any mitral regurgitation had higher 30-day and 1-year mortality rates, and mitral regurgitation was independently associated with increased 1-year mortality. 92 Echocardiography performed within 30 days after acute MI revealed mitral regurgitation in 50% of a cohort of 773 patients. 93 A murmur was not detected by cardiac auscultation in 54% of patients with mild and 31% of patients with moderate or severe mitral regurgitation. 93 Among 30-day survivors of an MI, during a mean follow-up period of 4.7 years moderate or severe mitral regurgitation detected by echocardiography within 30 days of MI was associated with a 55% increase in the relative risk (RR) of death independent of age, gender, left ventricular ejection fraction (EF), and Killip class. 93

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Harvesting the gastroepiploic artery

Tohru Asai , in Technical Aspects of Modern Coronary Artery Bypass Surgery, 2021

Postoperative course and follow-up

The anterior opening part of the diaphragm and the peritoneum are closed with the same continuous heavy silk suture to leave a small loophole for the GEA route, and the chest is closed in the usual fashion. Most patients with GEA grafting can take soft diet from postoperative day one, like other heart surgery patients. For use of the skeletonized GEA, calcium channel blockers have not been found necessary in the postoperative protocol for these patients, whereas they may be needed for maintenance of RA conduit size. In our practice, early graft patency is checked by CT angiography prior to discharge, as shown in Fig. 7.9 . Transcutaneous color Doppler echocardiography is also reported effective for noninvasive assessment of the GEA [29,30].

Figure 7.9. GEA sequential grafting by CT angiography. GEA, Gastroepiploic artery.

During the postoperative follow-up period, should abdominal surgery become necessary, it can be done with awareness and care. Sakai et al. [31] reported 14 various abdominal surgeries among their 278 CABG cases with an in situ GEA. When they found rerouting of the GEA necessary in the course pancreaticoduodenectomy, the surgeries was nevertheless performed safely without complications.

Diaphragmatic hernia after CABG using the GEA occurs very rarely. Shimamura et al. [32] reported a case and reviewed 11 previously reported cases, from 7 days to 9 years after CABG. Superiority of the anterior route in prevention of diaphragmatic hernia has been proposed but not proven. Risk factors are the creation of a large diaphragmatic orifice and conditions that increase intraabdominal pressure. Once herniation is diagnosed, prompt surgery is recommended to prevent impairment of the GEA and visceral organs. Careful closure of the diaphragmatic opening and increased awareness for this complication are mandatory precautions.

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Imaging of Mitral Regurgitation

J.B. Strom , ... C.W. Tsao , in Encyclopedia of Cardiovascular Research and Medicine, 2018

Trans-Thoracic Echocardiography

The most common imaging modality used to identify mitral regurgitation is trans-thoracic echocardiography (TTE). Two-dimensional imaging or M-mode may identify abnormalities in left ventricular global or regional systolic function, atrial size and function, and abnormalities with the mitral valve or valvular apparatus, including valvular vegetations, congenital abnormalities, and commissural thickening, which may indicate the likely etiology for regurgitation. Furthermore, color Doppler echocardiography permits detection of the mitral regurgitation jet, assessment of jet direction, and evaluation of the severity of disease including jet area and vena contracta ( Fig. 6 ). Continuous and pulse wave Doppler may be used to calculate several markers of degree of regurgitation such as EOA, regurgitant fraction, and regurgitant volume. Additionally, examination of flow patterns may reveal alterations consistent with severe disease such as blunting or reversal of systolic flow in the pulmonary veins or significant pulmonary hypertension ( Fig. 7 ). Stress echocardiography using TTE can additionally identify patients with inducible pulmonary hypertension with exercise, stress-induced ischemic mitral regurgitation, and latent left ventricular systolic dysfunction (Nishimura et al., 2017). Echocardiography can suggest concomitant valvular lesions, mitral stenosis, and underlying problems with left ventricular filling that may contribute to regurgitant severity. While evaluation of regional or global changes in left ventricular deformation using tissue Doppler or speckle-tracking strain imaging holds promise for better defining subclinical left ventricular dysfunction, lack of intervendor standardization on normal values for strain has impaired more widespread adoption of this technology (Collier et al., 2017). Furthermore, while 3D echocardiography has been shown to more accurately define left ventricular ejection fraction compared to 2D echocardiography and thus may predict impairment in left ventricular ejection at an early disease stage, there has not been widespread adoption of this technology for TTE use at the current time (Zoghbi et al., 2017).

Fig. 6. Color flow doppler representation of severe mitral regurgitation. This zoomed-out apical four chamber view of a transthoracic echocardiogram in a patient with an underlying cardiomyopathy demonstrates severe functional mitral regurgitation (arrow) directed into the right pulmonary veins. The jet of mitral regurgitation has a large area on color flow Doppler and extends to the back wall of the left atrium, suggesting a large degree of regurgitant volume.

Fig. 7. Continuous wave Doppler of mitral regurgitation. This continuous wave spectral Doppler image of a patient with mitral regurgitation demonstrates high velocity flow during systole consistent with mitral regurgitation (arrow). Both the density and shape of the continuous wave jet can be used to help quantify the severity of mitral regurgitation. Moreover, the peak velocity and integral of the observed velocities is used in the calculation of the effective regurgitant orifice using the PISA method.

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Physiological Adaptations of the Heart in Elite Athletes

A. D'Andrea , ... R. Calabrò , in Encyclopedia of Cardiovascular Research and Medicine, 2018

Exercise Stress Echocardiography

Exercise stress echocardiography (SE) is a feasible, low cost, widely available, and safe technique and is better accepted than pharmacological stress echocardiography by athletes. It gives information about cardiac function, reserve, exercise capacity, and arrhythmias.

SE exercise in athletes may have three different clinically relevant targets besides assessment of ischemia: intraventricular gradients (detected by Continuous Wave (CW) Doppler examination of the Left Ventricular Outflow Tract (LVOT)), pulmonary hemodynamic (Systolic Pulmonary Arterial Pressure (SPAP), LV filling pressure), and evolution of mitral regurgitation (by color Doppler echocardiography), lung sonography for detection of pulmonary congestion (as B-lines). An exercise SE test in athletes can give valuable information about cardiac function, reserve, exercise capacity, and arrhythmias ( Lancellotti et al., 2016).

Exercise stress echo is of particular interest in endurance-trained athletes with EF <   45%–50% at rest to test if there is contractile reserve (EF increase >   5%) during exercise; a considerable EF increase suggests low EF at rest to be related to low preload, and not to LV systolic dysfunction (Galderisi et al., 2015).

SE performed in athletes with LV hypertrophy complaining of shortness of breath or tendency to syncope; a suggestive finding could be an LVOT gradient >   50   mmHg during or immediately after exercise in the presence of symptoms. The development of a gradient during exercise in symptomatic athletes is, however, a frequent finding and might help link the reported symptoms (postexercise dizziness or syncope) to a potential cause (the development of an intraventricular gradient) (Cotrim et al., 2010).

Finally stress lung ultrasound (B-lines detection during or immediately postexercise) is useful in two separate settings, HF and extreme physiology.

In healthy elite apnoea, high-altitude trekkers, scuba divers, and extreme athletes involved in sports such as triathlon or marathon, B-lines can be detected in the absence of symptoms of pulmonary oedema (Fagenholz et al., 2007).

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Mechanical Complications of Acute Myocardial Infarction

Kanu Chatterjee , ... Edward McNulty , in Cardiac Intensive Care (Second Edition), 2010

Diagnosis

The ECG most frequently reveals recent inferior or inferoposterior MI (55%); however, location of the index infarction is anterior (34%) and posterior (32%) in patients with severe mitral regurgitation and cardiogenic shock. 34 In occasional patients, only ST-T abnormalities of "shell infarct" are present .Radiographic evidence of acute severe pulmonary edema is invariably present.

Doppler and transthoracic echocardiography should be performed in all patients. Transthoracic echocardiography is less sensitive than transesophageal echocardiography for visualization of the disrupted mitral valve (45% to 50% versus 100%), 43-45 but it is 100% sensitive for the detection by color Doppler echocardiography of the resultant severe mitral regurgitation ( Fig. 19-1A). 43,46

Echocardiography shows the underlying regional left ventricular wall motion at the site of ischemia/infarction and excludes ventricular septal or free wall rupture. 43,47 A partial papillary muscle rupture may be detectable by two-dimensional echocardiography. A complete rupture is diagnosed when the head of the papillary muscle is seen as a freely moving mobile mass attached to the mitral valve chordae ( Fig. 19-1B ). 44,46,48-50

Right heart catheterization with the use of balloon flotation catheters is unnecessary for the diagnosis of severe mitral regurgitation. If it is undertaken, however, it reveals giant v waves in the pulmonary capillary wedge pressure tracing (Fig. 19-2). Giant v waves may also be present in patients with ventricular septal rupture. In ventricular septal rupture, increased pulmonary venous return owing to the large left-to-right shunt to a left atrium with normal size and compliance is associated with an accentuated v wave. The presence of a reflected v wave in a pulmonary artery pressure tracing is diagnostic of acute or subacute severe mitral regurgitation. 51 For the diagnosis of left-to-right shunt, step-up in oxygen saturation in the pulmonary artery is detected. In some patients with severe acute mitral regurgitation, reflux of the oxygenated pulmonary venous blood occurs in the distal pulmonary artery branches. For the diagnosis of ventricular septal rupture, oxygen saturation should be determined in the proximal pulmonary arteries.

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