Transcatheter aortic valve replacement

WikiDoc Resources for Transcatheter aortic valve replacement
Articles
Most recent articles on Transcatheter aortic valve replacement Most cited articles on Transcatheter aortic valve replacement Review articles on Transcatheter aortic valve replacement Articles on Transcatheter aortic valve replacement in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Transcatheter aortic valve replacement Images of Transcatheter aortic valve replacement Photos of Transcatheter aortic valve replacement Podcasts & MP3s on Transcatheter aortic valve replacement Videos on Transcatheter aortic valve replacement
Evidence Based Medicine
Cochrane Collaboration on Transcatheter aortic valve replacement Bandolier on Transcatheter aortic valve replacement TRIP on Transcatheter aortic valve replacement
Clinical Trials
Ongoing Trials on Transcatheter aortic valve replacement at Clinical Trials.gov Trial results on Transcatheter aortic valve replacement Clinical Trials on Transcatheter aortic valve replacement at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Transcatheter aortic valve replacement NICE Guidance on Transcatheter aortic valve replacement NHS PRODIGY Guidance FDA on Transcatheter aortic valve replacement CDC on Transcatheter aortic valve replacement
Books
Books on Transcatheter aortic valve replacement
News
Transcatheter aortic valve replacement in the news Be alerted to news on Transcatheter aortic valve replacement News trends on Transcatheter aortic valve replacement
Commentary
Blogs on Transcatheter aortic valve replacement
Definitions
Definitions of Transcatheter aortic valve replacement
Patient Resources / Community
Patient resources on Transcatheter aortic valve replacement Discussion groups on Transcatheter aortic valve replacement Patient Handouts on Transcatheter aortic valve replacement Directions to Hospitals Treating Transcatheter aortic valve replacement Risk calculators and risk factors for Transcatheter aortic valve replacement
Healthcare Provider Resources
Symptoms of Transcatheter aortic valve replacement Causes & Risk Factors for Transcatheter aortic valve replacement Diagnostic studies for Transcatheter aortic valve replacement Treatment of Transcatheter aortic valve replacement
Continuing Medical Education (CME)
CME Programs on Transcatheter aortic valve replacement
International
Transcatheter aortic valve replacement en Espanol Transcatheter aortic valve replacement en Francais
Business
Transcatheter aortic valve replacement in the Marketplace Patents on Transcatheter aortic valve replacement
Experimental / Informatics
List of terms related to Transcatheter aortic valve replacement

Editors-in-Chief: Roger Laham, M.D., C. Michael Gibson, M.S., M.D.; Jeffrey J. Popma, M.D.

Assistant Editor-In-Chief: Saleh El Dassouki, MD [1]

Please Join in Editing This Page and Apply to be an Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Synonyms and keywords: TAVI, Edward's valve, Edward's SAPIEN transcatheter heart valve, CoreValve, percutaneous aortic valve replacement, PAVR

Overview

Untill recently, aortic valve replacement (AVR) was the only effective treatment to severe symptomatic aortic stenosis. However, over the past decade percutaneous treatment of aortic valve disease with implantation of a stent-based valve prosthesis has been introduced as a new treatment in patients considered inoperable because of severe co-morbidities. In Transcatheter Aortic Valve Implantation (TAVI) also known as Percutaneous Aortic Valve Replacement (PAVR), a synthetic valve is transported to the heart through a small hole made in groin. This procedure can be compared to that performed when placing a stent, or performing balloon angioplasty. Traditional aortic valve replacement is an invasive surgical procedure, with considerable mortality and morbidity, especially in more fragile patients. In the newly developed TAVI procedure, the dysfunctional aortic valve is replaced percutaneously, which removes the need for open heart surgery.

Valve types

CoreValve

The CoreValve device was first inserted in 2005.It consists of three leaflets of bioprosthetic pericardial tissue valve mounted on a self-expendable nitinol stent, which expands from the left ventricular outflow tract (LVOT) to the ascending aorta. Initially the device had a 25F profile, but it rapidly evolved to the current 18F device which lead to easier percutaneous insertion and better handling of the device. A third generation device is currently available, which measures 50 mm in height that is divided into 3 sections:

1. An inflow portion designed to fix the valve to the annulus.
2. An outflow portion designed to attach the frame of the device to the ascending aorta to stabilize it.
3. A central portion designed to prevent the obstruction of the coronaries.

Procedure

The diseased valve is moved aside by the inflation of a balloon Aortic balloon valvuloplasty, than the Corevalve prosthesis is loaded in a specialized delivery catheter and advanced to the stenosed aortic valve. Once correctly positioned, the external part of the delivery system is progressively retracted, deploying the Corevalve Prosthesis. The delivery catheter is then closed and retrieved.

Techniques

Two major catheter based techniques for replacing the aortic valve have been investigated : retrograde percutaneous implantation and direct apical puncture. An antegrade transseptal approach has also been studied but not fully adopted.

• Retrograde approach: After a routine Aortic balloon valvuloplasty, a 22F or 24F sheath is advanced from the femoral artery to the aorta. The manipulation of the prosthesis around the aortic arch and through the stenotic valve is facilitated by a steerable, deflectable catheter. Rapid ventricular pacing is used to decrease cardiac output while the delivery balloon is inflated to deploy the prosthesis within the annulus.

• Transapical antegrade approach: An alternate catheter based method consists of a direct left ventricular apical puncture and antegrade aortic valve implantation via a small anterolateral thoracotomy without the need of cardiopulmonary bypass or sternotomy. This technique is used in patients with severe peripheral arterial disease and heavily calcified ascending aorta and arch (porcelain aorta) who have an increased risk of stroke and other embolic events using other approaches.

Complications

Following CoreValve implantation:

• QRS duration: In one observational study of 270 patients, the QRS duration increased from 105±23 milliseconds at baseline to 135±29 milliseconds following TAVI. (P<0.01).
• Left Bundle Branch Block (LBBB): The incidence of left bundle-branch block increased from 13% at baseline to 61% following TAVI (P<0.001).
• Permanent pacemaker implantation: Approximately one third of patients will require a permanent pacemaker be implanted by 30 days with a median time to insertion of 4 days (interquartile range, 2.0 to 7.75 days).
• Multivariate predictors of permanent pacemaker implantation included:

1. Periprocedural atrioventricular block (odds ratio, 6.29; 95% confidence interval, 3.55 to 11.15)
2. Balloon pre-dilatation (odds ratio, 2.68; 95% confidence interval, 2.00 to 3.47)
3. Use of a larger 29 mm CoreValve prosthesis (odds ratio, 2.50; 95% confidence interval, 1.22 to 5.11)
4. The interventricular septum diameter (odds ratio, 1.18; 95% confidence interval, 1.10 to 3.06)
5. A prolonged QRS duration (odds ratio, 3.45; 95% confidence interval, 1.61 to 7.40)