Advances in Healing C A R D I OVA S C U L A R I N N OVAT I O N S
VOLUME 1
A N E WS L E T T E R F O R R E F E R R I N G P H Y S I C I A N S
2 Implementing Risk Reduction 4 Coronary Intervention through Radial Artery 4 Women & Heart Disease
Transcatheter Aortic Valve Replacement:
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An Innovative Treatment for High-Risk Patients with Aortic Stenosis
ABSTRACT: Aortic stenosis typically is a disease of the elderly, many of whom are poor candidates for open heart surgery with valve replacement. Transcatheter aortic valve replacement (TAVR) is a minimally invasive, catheter-based procedure for implanting a prosthetic tissue valve inside a stenotic native aortic valve. TAVR has been shown to be superior to medical therapy in the treatment of inoperable patients with aortic stenosis, and that it was equivalent to standard surgical valve replacement in high operative risk patients. Transcatheter aortic valve replacement (TAVR) is a minimally invasive, catheter-based procedure for implanting a prosthetic tissue valve inside a stenotic native aortic valve. For over 40 years, the treatment standard for severe, symptomatic aortic stenosis (AS) has been open heart surgery with valve replacement. While this approach yields excellent results, many older patients are poor candidates for major surgery and have thus been limited to largely palliative measures, including medication or balloon valvuloplasty. TAVR provides another option for selected high-risk elderly patients. ABOUT AORTIC STENOSIS In AS, a buildup of calcium restricts the normal functioning of the aortic valve. Ultimately, the size of the valve opening can shrink from the size of a quarter down to a size that may be as small as a pencil eraser, severely limiting the flow of blood into the aorta. AS can have an insidious onset, with patients remaining asymptomatic or experiencing vague, generalized symptoms such as reduced energy, strength, and activity levels. As the valve opening narrows down significantly, the patient may begin to complain of chest pain, shortness of breath, or syncope. More than 50% of patients with medically managed, severe AS will die within 2 to 3 years. AS typically occurs in the elderly, more commonly in men, with a prevalence of 2% to 9% in individuals older than 75 years. For persons with a congenitally bicuspid valve, about 1% to 2% of patients, symptomatic AS may develop as early as middle age. HOW TAVR WORKS AS can be treated very effectively with open heart surgery that includes excision of the diseased valve and replacement with a tissue or mechanical valve. However, AS is most common in an elderly
C A R R O L LT O N
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DALLAS
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DENTON
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FORT WORTH
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GARLAND
population where significant comorbidities (e.g., chronic obstructive pulmonary disease, vascular or cerebrovascular disease, or renal disease) may contraindicate major surgery. Nearly a quarter of elderly patients with symptomatic AS fall into this category and, until recently, there was no other good option for them. In TAVR, a new tissue valve is delivered by a variety of catheter-based approaches and implanted inside the native valve. Most commonly, a catheter is inserted through the femoral artery. (If the artery is diseased or too small, a transapical, transaortic, or subclavian route can also be used.) The prosthetic valve is compressed or “crimped” and delivered by fluoroscopic and echo guidance to the aortic valve, where it is balloon-expanded, pushing the diseased native valve leaflets aside. In this country, the procedure is typically done under general anesthesia on a beating heart, so there is no need for cardiopulmonary bypass. Currently, there are two FDA approved TAVR devices in the US. The Edwards SAPIEN® valve and the Medtronic CoreValve®. The Edwards SAPIEN® valve was approved by the US Food and Drug Administration in 2011 for patients who are not good candidates for surgical aortic valve replacement. The Medtronic CoreValve® received FDA approval in January 2014 and has the ability to be delivered through smaller delivery systems (14Fr.-18Fr.). Recent international trials have shown that both the Edwards SAPIEN® valve and the Medtronic CoreValve® are superior to medical therapy in the treatment of inoperable patients with AS, and that it was equivalent to standard surgical valve replacement in high operative risk patients. An ongoing trial is testing whether the procedure will be appropriate for intermediate-risk patients.
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