Echocardiographic Guidance of Procedures

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26 Echocardiographic Guidance of Procedures

Stuart J. Hutchison, Deborah Isaac, Mark Johnson, Robert Moss, Brad Munt

Jugular Venous Cannulation

Rationale and Role

To simplify jugular venous access by direct visualization and guidance

To minimize complications such as hematomas due to jugular venous transfixion, carotid artery puncture, jugular venous to carotid arterial fistula, pneumothoraces, multiple puncture, and failed procedures

Sequence

Place the patient in Trendelenburg position to increase the size of the neck veins.

With the skin cleaned and sterile, introduce the probe into a sterile plastic sheath.

Image from the anterior neck in the mid-portion, which overlies the internal jugular vein and the common carotid artery. The jugular vein, depending on the central venous pressure, may be (usually is) larger than the common carotid artery, but in volume-contracted or dehydrated patients, the vein may be smaller than the artery. The vein may lie to the side of, anterolateral to (this is its usual location in the mid-neck), anterior but slightly lateral to, or completely anterior to the artery.

The most desirable site for cannulation is where the vein is substantially at least lateral to the artery, so that inadvertent transfixion of the vein runs little risk of inadvertently puncturing the common carotid artery. Avoid locations where the jugular vein is directly anterior to the artery.

The vein is identified by the following:

• Distention with a partial Valsalva maneuver

• Compressibility and anterior flattening by slight pressure application with the probe

If the vein is generously full, the needle is inserted carefully through the taut anterior wall of the vein until the tip is a few millimeters into the lumen.

If the vein is full but limp, have the patient make a partial Valsalva maneuver to distend the vein, providing a larger target for the needle puncture and a more taut anterior wall.

It is easiest if the patient is told to take a breath (inspire) before he or she is told to strain (perform a Valsalva maneuver). Guiding the patient in practicing the performance of a Valsalva maneuver before the procedure is helpful for patients who are not familiar with it.

Visualize the wire extending from the needle.

Visualize the sheath within the lumen following its insertion.

Be aware of the presence of jugular venous valves, a normal aspect of anatomy. Insertion beneath the valves may simplify the procedure.

Be aware of the appearance of jugular venous thrombus, a common residua of prior catheter and wire insertions

Pro

With practice and experience, a high degree of proficiency can be achieved.

Cons

Some dexterity and proficiency with the technique of direct ultrasound imaging guidance are needed, resulting in a learning curve (Figs. 26-1 to 26-3).

Endomyocardial Biopsy

To reliably diagnose heart transplant rejection, right ventricular endomyocardial biopsy (percutaneous procurement of endomyocardial samples from the right ventricle ^1,²) remains the gold standard. Right ventricular endomyocardial biopsy also is a valuable way to assist with diagnosis and management of suspected myocarditis, infiltrative cardiomyopathy, or other unexplained ventricular dysfunction.

Percutaneous right ventricular endomyocardial biopsy most commonly is performed using cannulation of the right internal jugular vein. In circumstances where this vessel is not usable, the femoral vein can be used for this purpose. Cardiologists traditionally have relied on fluoroscopic guidance for placement of the bioptome. Using frontal-plane fluoroscopic guidance, the bioptome is directed toward the right ventricular septum to obtain right ventricular samples. Bioptome contact with the right ventricular septum is confirmed by the presence of ventricular ectopic beats, and samples are taken from that site. Typically at least four biopsy samples are obtained, because a minimum of three adequate biopsy samples are required for histologic diagnosis. The use of fluoroscopy to guide right ventricular endomyocardial biopsy has a number of drawbacks: it provides only approximate bioptome placement information; exposes both the patient and physician to radiation; and requires use of the cardiac catheterization laboratory—a facility in high demand. Using fluoroscopic guidance, the complication rate ranges from 6% to 14%,^3,⁴ with possible complications including myocardial perforation, tricuspid valve apparatus disruption, arrhythmias, coronary artery to right ventricular fistula, and inadvertent arterial punctures. A significant limitation of fluoroscopic guidance for right ventricular endomyocardial biopsies is that the bioptome placement and subsequent sampling area are limited due to inability to place the bioptome precisely, leading to repeated sampling from the same area. This contributes to biopsies that consist predominantly of scar from previous biopsy sites, which are inadequate for histologic assessment, and to reduced sensitivity due to the potentially focal nature of rejection or other cardiac histologic processes.

Rationale and Role

Real-time visualization

Of venipuncture to lessen access complications

Of bioptome placement/biopsy sampling

• To lessen complications

• To increase diagnostic yield

Sequence

Echocardiographically guided endomyocardial biopsy usually is performed in the echocardiography laboratory, with the assistance of an echosonographer and a nurse.

The person performing the biopsy procedure stands at the head of the bed, with the echosonographer and echocardiography machine to the patient’s left and the nurse and sterile tray to the patient’s right.

Echocardiographic images are obtained prior to venous cannulation to determine the optimal window and views for visualization of the right atrium and ventricle; to briefly assess left and right ventricular systolic function, the presence and amount of pericardial fluid present, and the presence and degree of tricuspid regurgitation; and to estimate right ventricular systolic pressure. Preprocedure imaging also determines the ideal patient positioning. In many cases supine imaging is adequate, but patients may be moved into the left lateral lying position after initial insertion of the jugular venous sheath to optimize visualization of the right-sided cardiac structures. Ultrasound assessment of the right internal jugular vein may be done at this time, to assist in venous cannulation.

Venous access is obtained using standard Seldinger technique via the right internal jugular vein, with a sheath left in place.

The bioptome is then inserted through the venous sheath into the right atrium.

Using echocardiographic imaging to visualize the right-sided chambers and tricuspid valve and apparatus, the bioptome is then passed across the tricuspid valve into the right ventricle. The endocardial surfaces of the right ventricle are visualized, and the sonographer “follows” the advancement of the bioptome, keeping the forceps head of the bioptome clearly imaged throughout the procedure. The operator maneuvers the bioptome to the desired location, avoiding the moderator band and tricuspid apparatus. Once the bioptome is approximated next to the endomyocardial surface in the desired position, the jaws of the bioptome are opened, and the bioptome is advanced gently against the endomyocardium. Once in place, the jaws are closed and, with a very gentle tug, the biopsy sample is obtained. The bioptome is removed, the sample is placed in sterile saline, and the procedure is repeated until an adequate number of samples have been obtained.

Samples may be taken from the mid to distal right ventricular septum, apex, and free wall in post–cardiac transplant patients, but are usually restricted to the mid- to distal right ventricular septum in non–transplant patients.

Post-procedure echocardiographic imaging assesses for changes in the presence or degree of tricuspid regurgitation and/or pericardial fluid.

Two decades ago, Miller published his successful results using echocardiographic guidance for right ventricular endomyocardial biopsy.⁵ Despite this and other reports of reduced costs and an improved safety profile using echocardiography to guide right ventricular endomyocardial biopsy in adults and children,⁶^–¹⁰ this technique has not gained widespread popularity.

Pros

Echocardiographic guidance of right ventricular endomyocardial biopsy affords considerable benefits over traditional fluoroscopic guidance.

Improved safety

• As well as elimination of radiation exposure, there is less likelihood of cardiac damage caused by poor visualization—such as inadvertently entering the coronary sinus or damage to tricuspid apparatus—because of the superior means to identify anatomic cardiac landmarks. Intracardiac leads and catheters can be easily visualized and avoided for bioptome placement.

• The uncommon complication of pericardial effusion development can be immediately identified and addressed if endomyocardial biopsy is performed under echocardiographic guidance.

• Ultrasound guidance can be used to assist with difficult venous cannulation, which affords both a safety and convenience advantage by reducing inadvertent carotid artery punctures and repeated/multiple access attempts.

Provision of additional information

• A brief assessment of left and right ventricular systolic function, valvular regurgitation, right ventricular/pulmonary artery systolic pressure, and presence of pericardial fluid can be performed to provide current and additional structural and functional information.

• Although most patients will undergo right ventricular biopsy in the echocardiography laboratory, biopsies may be performed in the rooms of critically ill patients in the cardiac intensive care unit, saving staff time and eliminating the inconvenience of transporting the patient.

Improved sampling

• An expanded endomyocardial sampling area improves the sensitivity for the diagnosis of rejection, which may be a focal process. In adequate samples may be obtained in up to 8% of biopsies performed under fluoroscopy and as low as 0%⁶ under echocardiographic guidance.

• Using echocardiography, the bioptome can be directed away from scarred previous biopsy sites, and samples can be obtained safely from sites along the mid- to distal right ventricular septum and apex.

• In patients who are more than 6 to 8 weeks post–cardiac transplantation, biopsies may be safely obtained from the patient’s right ventricular free wall by experienced operators.⁵ Biopsy samples should be limited to the right ventricular septum in patients who are within 6 to 8 weeks after cardiac transplantation, and in those with native hearts.

Directed biopsies

• Echocardiographic biopsy guidance allows for targeted biopsy of intracardiac (i.e., within the right ventricle and right ventricular outflow tracts) masses due to the ability to clearly image the target area and the bioptome.

• Performance of right ventricular biopsy under echocardiographic guidance reduces costs up to 50%⁷ because it avoids the use of the cardiac catheterization laboratory, and it requires fewer staff resources—typically, one nurse and one echocardiography technician are needed, compared to the need for a scrub nurse, a circulating nurse, and a monitoring technician in the catheterization laboratory.

Despite valid and compelling benefits, there has been reluctance to adopt echocardiographically guided right ventricular biopsy. A typical argument against the technique is the perception that it is difficult to get adequate echocardiographic images in some patients. In 90% of patients, however, the standard apical four-chamber view can be used to view the bioptome head,⁶ although modifications of this view may be necessary to provide optimal imaging during bioptome manipulation.

Cons

Need for the operator to develop confidence (Figs. 26-4 to 26-10)

Pericardiocentesis

Rationale and Role

Echocardiography provides the most versatile means to guide pericardiocentesis by guiding access site selection and needle entry orientation, visual confirmation of needle entry into the pericardial space, avoidance of cardiac perforation, and verification of successful drainage.

Sequence

• Standard transthoracic study to establish the location and distribution of the pericardial fluid

• Determination of the site that provides shortest distance to enter the pericardial fluid and the best orientation to minimize needle trauma to the heart (by orienting into the fluid space away from the heart chambers)

During the procedure

• Visual identification of the needle orientation and entrance into the pericardial space

• Visual confirmation of the wire within the pericardial space, with or without visual confirmation of the injection of agitated saline within the pericardial space

• Visualization of reduction of the pericardial fluid

Unlike chest CT scan, real-time imaging by echocardiography of the heart’s motion within the pericardial space enables determination of the dimension of pericardial fluid throughout the cardiac cycle, which can vary considerably between diastole and systole.

During the procedure, use of a sterile sleeve to enable scanning immediately beside the site of puncture allows for real-time imaging.

Pros

Portability: can be performed at any bedside

Real-time imaging during the procedure maximizes procedural awareness.

Con

Learning eye–hand coordination to image the needle and wires requires willingness (Figs. 26-11 to 26-17).

Transseptal Puncture

Rationale and Role

Visual guidance by transesophageal echocardiography (TEE) of interatrial septal puncture to lessen risk of inadvertent puncture complications and identify any complications that do occur

Guidance of complex transseptal punctures in cases of kyphosis or scoliosis where the heart orientation (specifically that of the interatrial septum) within an abnormal chest cavity is unclear without imaging

Sequence

Visualization of the catheter and needle approaching the heart (inferior vena cava/bicaval view)

Visualization of the needle contacting the interatrial septum away from the margin of the septum

Visualization of the needle tenting the interatrial septum away from the margin of the septum

Visualization of the needle/catheter in the left atrium

Visualization of the catheter flush (small bubbles) in the left atrium

Pros

Straightforward

Identification of the presence of a patent foramen ovale alerts one that the interatrial septum may be inadvertently/quickly crossed.

Con

Performing TEE on a supine patient requires attention and measures to protect the airway (Fig. 26-18).

Catheter Mitral Balloon Valvuloplasty

Rationale and Role

TEE guidance of catheter balloon valvuloplasty affords a means by which to

• Guide atrial septal puncture in difficult cases

• Assess the degree of post–balloon inflation mitral insufficiency in cases of preprocedure moderate mitral regurgitation (MR) where there is concern about precipitating severe MR.

Sequence

As described for atrial septal puncture guidance

Color Doppler flow mapping and pulmonary venous sampling to determine the degree of mitral insufficiency incurred by balloon inflation

Pro

Useful when contrast sparing is desirable (e.g., renal insufficiency). Contrast ventriculography is otherwise used to assess the degree of mitral insufficiency post–balloon inflation.

Cons

Not needed for the average case

Performing TEE on a supine patient requires attention and measures to protect the airway (Figs. 26-19 to 26-22).

Percutaneous Aortic Valvuloplasty

Rationale and Role

Traditional aortic valve replacement is performed via median sternotomy, cardiopulmonary bypass, aortotomy, resection of the native aortic valve, and insertion of a prosthetic aortic valve. Approximately 60,000 aortic valve surgeries are performed per year in North America; however, many patients in need of aortic valve surgery never undergo it due to prohibitive and generally noncardiac risks.

Percutaneous aortic valve (PAV) replacement, as an alternative to open-chest aortic valve replacement, is emerging and is undergoing clinical investigation as an alternative to conventional surgery. Valves can be inserted percutaneously via retrograde aortic cannulation or anterogradely via a small thoracotomy.

Two PAV prostheses currently are in clinical use:

The CoreValve prosthesis (Fig. 26-23)

The Edwards-Sapien prosthesis (Fig. 26-24)

Echocardiography has an integral role in PAV implantation pre-, intra-, and post-procedurally, as two-dimensional imaging, especially by TEE, is generally very well-suited to delineate left ventricular outflow tract and aortic valve anatomy, and the hemodynamics of stenosis and insufficiency.

Sequence

Preprocedural Assessment

Severity/morphology of aortic stenosis

Routine transthoracic echocardiography (TTE) is done to assess for aortic stenosis, including ensuring that the stenosis is valvular and determining, at a minimum, the valve gradient and aortic valve area. (Other values such as the dimensionless index may be helpful in some situations.)

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