September 1, 2009 – Echocardiography with Doppler is the method of choice for the noninvasive evaluation of prosthetic valves, according to a new guideline document in the September issue of the Journal of the American Society of Echocardiography (JASE).
The document offers a review of echocardiographic and Doppler techniques used in the assessment of prosthetic valves, and provides recommendations and general guidelines for evaluation of prosthetic valve function, based on the scientific literature and consensus of an international panel of experts. The guidelines have been endorsed by five prominent health organizations, including the American Heart Association, American College of Cardiology, European Association of Echocardiography, Japanese Society of Echocardiography, and the Canadian Society of Echocardiography.
“Over the last 40 years, a large variety of prosthetic valves have been developed with the aim of improving blood flow function, increasing durability and reducing complications,” said Dr. William A. Zoghbi, of Methodist DeBakey Heart and Vascular Center, Houston, Texas, and a lead author of the article. “Nevertheless, there is no ideal valve and all prosthetic valves are prone to dysfunction. The guidelines are critical to handling the evaluation of prosthetic valves and emphasize the importance of echocardiography.”
In patients with significant valvular stenosis or regurgitation, an intervention on the valve with either repair, valvuloplasty or valve replacement is inevitable. While valve repair is now frequently performed, especially for mitral and tricuspid regurgitation, valve replacement remains common, particularly in adults. This enlarging cohort may be difficult to assess. Symptoms may be nonspecific making it difficult to differentiate the effects of prosthetic valve dysfunction from ventricular dysfunction, pulmonary hypertension, pathology of the remaining native valves or noncardiac conditions.
“Although the physical examination can alert the clinician to the presence of significant prosthetic valve dysfunction, diagnostic methods are often needed to assess the function of the prosthesis,” said Dr. Zoghbi.
The recommendations outline the importance of a comprehensive evaluation for optimal assessment of prosthetic valve function. This includes obtaining pertinent clinical information such as date of valve replacement; type and size of the prosthetic valve; height/weight/body surface area; symptoms; and related clinical findings, blood pressure and heart rate.
Additionally, imaging of the valve from multiple views is recommended with particular attention to motion of leaflets or occluder, presence of calcification on the leaflets or abnormal echo density on the various components of the prosthesis, and valve sewing ring integrity and motion.
The guidelines stress the importance of Doppler echocardiography of the valve to evaluate some of the following parameters:
• Contour of the jet velocity signal
• Peak velocity and gradient
• Mean pressure gradient
• Velocity-time integral of the jet
• Doppler velocity index
Finally, the guidelines offer considerations for the intraoperative patient, other techniques for assessing replacement heart valves and considerations for early versus late complications of prosthetic valves.
The full ASE Guideline Document, “Recommendations for Evaluation of Prosthetic Valves with Echocardiography and Doppler Ultrasound” is available at www.asecho.org.
