New and Evolving Roles for Echocardiography - Guiding Percutaneous Cardiac Procedures

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Citation
US Cardiology, 2007;4(2):37-40

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Non-invasive imaging of the heart continues to evolve and improve. Cardiovascular ultrasound (echocardiography) continues to play an important role in the diagnosis and assessment of responses to therapy of many cardiac conditions. Even as the clinical applications of newer techniques such as cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMRI) increase, the role of echocardiography remains strong since it has unique capabilities. One of the strengths of echocardiography is that it can be brought to the patient’s bedside easily. In fact, features of ultrasound machines such as 3D, 2D and trans-oesophageal echo, spectral and colour Doppler imaging, strain rate imaging and even intra-cardiac imaging can be performed on devices that are increasingly portable. Thus, it is easier to provide echocardiography around the hospital, office or other environments.
Devices exist that enable many cardiovascular procedures to be performed that once required open-heart surgery, but now catheters can be used in a much less invasive manner. Percutaneous coronary interventions such as balloon angioplasty and coronary artery stent placement are the most common examples of this evolution in cardiovascular care, but many other treatment opportunities are now present in the catheterisation laboratory. Many of these new treatments require imaging of the heart in a manner different from fluoroscopy so that the position of the devices can be optimised. By virtue of its ease of use, safety, lack of radiation, low cost and portability, echocardiography has come to play a key role in selecting patients for and guidance of these procedures. This article will highlight echocardiography and its role in some of these new catheter-based treatments. Table 1 lists some of these representative procedures.

Percutaneous Mitral Valvuloplasty

One of the earliest interventions in the catheterisation lab utilising echocardiography was the treatment of mitral stenosis with balloon dilation or percutaneous mitral valvuloplasty (PMV). PMV has now replaced surgery as the initial therapy for this disorder. Trans-thoracic echocardiography is used to assess the mitral valve for degrees of thickening, calcification, regurgitation and other characteristics to determine patient suitability for the procedure. Typically, trans-oesophageal echo is performed to exclude thrombus in the left atrium as this is a contraindication to the procedure. Trans-thoracic echocardiography is often performed in the catheterisation laboratory during the procedure to ensure that as the valve is dilated it is not dilated so excessively that mitral regurgitation deteriorates to an intolerable degree (see Figure 1).

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