January 31st, 2012
Guiding TAVR into Clinical Practice
The ACC, AATS, SCAI, and STS have issued a critical consensus document to guide the use of transcatheter aortic valve replacement (TAVR) as it enters clinical practice in the U.S. (see also our CardioExchange news coverage here). CardioExchange Interventional Cardiology moderators Rick Lange and David Hillis posed the following questions to writing committee member Steven R Bailey, the Janey Briscoe Distinguished Professor of Medicine and Radiology and Chief of the Division of Cardiology at the University of Texas Health Science Center at San Antonio.
Rick Lange and David Hillis (RL and DH): Consensus guidelines are nothing new. Why are these getting so much publicity?
Steven Bailey: Guidelines now address two levels of clinical practice. The multisociety Clinical Practice Guidelines are based specifically upon peer reviewed studies that provide evidence on how to treat specific conditions or how to use specific modalities (STEMI, stable angina, echo, etc.). These recommendations are often population-based.
The Appropriate Use Criteria (AUC) are designed to provide assistance not only to specialists but also to the general physician who wants to understand how to use testing and procedures in specific patient scenarios. The AUC recommendations fall into three categories: Appropriate, when we have published information to support practice; Uncertain, when the procedure is commonly used in clinical practice but we do not have clear-cut information about its use in a specific scenario; and Inappropriate, when published data indicates possible harm. These guidelines serve as guideposts in areas that require further investigation.
The current document is an Expert Consensus statement, described by the ACC as follows:
Expert consensus documents are intended to inform practitioners, payers, and other interested parties of the opinion of the ACCF concerning evolving areas of clinical practice and/or technologies that are widely available or new to the practice community…These documents are evidence-based whenever possible but tend to be shorter than guidelines, as they are developed around a topic that is more narrowly focused, that is new or emerging, and for which a smaller body of evidence is available.
The interest is also driven by external groups (patients, payers, and other agencies) who have interests in how we provide care and what choices can be selected.
RL and DH: Transcatheter aortic valve replacement (TAVR) is heralded as “transformational.” Isn’t this a bit over the top?
Bailey: TAVR has transformed delivery of care for patients with valvular heart disease in two major ways. First, the proof of efficacy, in high-risk surgical patients as well as in patients who are not surgical candidates, sets the stage for evolution of this technology to smaller, more effective devices. This is similar to the evolution of surgical valves from the Hufnagel valve to the tissue valves we us today.
But perhaps the most important “transformation” has been in the development of a multidisciplinary team (cardiology, cardiothoracic surgery, echo, imaging, anesthesia, and geriatrics) to make decisions regarding the best care for individual patients.
RL and DH: Are you concerned that “real world” TAVR results won’t be as good as those reported in the PARTNER studies?
Bailey: We should expect that outcomes in “real world” patients may not be the same as in highly selected patients at the few experienced centers who participated in this pivotal study. The current process of only allowing the procedure at a limited number of centers, with state-of-the-art facilities and multidisciplinary teams who are actively assisted with patient selection and the initial procedures, will be very important in enabling the selection of those patients who are most likely to have outcomes similar to those seen in the PARTNER nonsurgical arm.
RL and DH: The data from all TAVR patients are supposed to be entered into a national database. Do you think this will be effective in assuring that TAVR is used appropriately?
Bailey: Follow-up of patients who receive TAVR is critically important to allow centers to compare their results to those seen regionally and nationally. It will not be the sole method for assuring appropriate use, but it is critical to ensuring accountability for outcomes.
RL and DH: The transcatheter valve alone will cost ≈$30,000. Is TAVR cost effective, especially since it is being used in an elderly population?
Bailey: The current cost analysis by Cohen et al. does suggest that the costs of TAVR, even in this elderly population, are consistent with costs that our society accepts for lifesaving and life-prolonging therapy such as dialysis. This becomes an important decision in each individual patient. Experience shows that these costs will likely decrease over time, resulting in a more favorable cost-effectiveness analysis.