Reference: Buellesfeld y colaboradores (JACC in press).
Percutaneous aortic valve replacement (AVR) is an innovative technique for the treatment of severe aortic stenosis (SAS); this technique has been incorporated with great enthusiasm in clinical practice, particularly for patients with excessive surgical risks. Due to the proximity of the aortic valve, AV node and His bundle, there is a possibility of altering myocardial conductivity during AVR. One of the most commonly used valves is CoreValve®, a self-expanding prosthesis valve (Medtronic, Minneapolis, Minnesota). Patient AV conduction disorders are not uncommon after implantation of this valve and require Permanent Pacemaker Insertion Periprocedural (PPM). However, it is unknown whether the need for PPM is associated with a worse outcome in patients after AVR. This hypothesis was recently evaluated in a retrospective study involving 353 high-risk patients, (mean age 82 years, logistic EuroSCORE of 25), who underwent AVR. In this study 40% of patients required pacemaker implantation. At 12 months follow-up, the total mortality rate of patients was 19.4% with PPM and 18% without PPM.
Comments: The periprocedural need of PPM does not appear to be a risk factor in patients undergoing AVR. This information is not a trivial issue because of the high rate of implants, especially with self-expanding valves. Differences in the design of the devices as an extension deeper into the outflow tract of the left ventricle and the carrying out of a constant force on the aortic annulus and subendocardial tissue, (due to its self-expanding properties), partly explain the changes in myocardial conduction observed with the CoreValve ® valve. Besides valve characteristics, patient characteristics such as severe septal hypertrophy, valvular calcification and right bundle branch block, as well as factors related to implantation technique of the valve (> 6 mm below the ring, predilation and relation between prosthesis and valve annulus size), increase the risk of changes in myocardial conduction tissue. Furthermore, there is no criteria consistency as regards the necessity of PPM, a fact which often depends on the threshold of each treating physician or institution.
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