Need for Permanent Pacemaker Uncommon After Sapien Valve Implantation

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Although some form of conduction disturbance is fairly common after transcatheter aortic valve replacement (TAVR), fewer than 5% of patients receiving a Sapien valve require permanent pacemaker implantation, according to an observational study published online July 9, 2012, ahead of print in the American Journal of Cardiology.

For the retrospective analysis, investigators led by Ron Waksman, MD, of the Medstar Washington Hospital Center (Washington, DC), examined electrocardiographic evidence of conduction system injury in 125 patients at their center who participated in the randomized PARTNER trial, 91 from the cohort of surgical high-risk patients and 34 from the cohort of inoperable patients. An electrocardiogram was recorded before and serially after the procedure. The mean age of patients was 84.2 years.

Left Anterior Hemiblock, Transapical Connection

Overall, 19 patients (15.2%) met the study definition of a new conduction defect, exhibiting the following indications (table 1).

Table 1. New Conduction Abnormalities after TAVR

Permanent Pacemaker Implantation

4%

Left Bundle Branch Block

4%

Left Anterior Hemiblock

7%


Interestingly, of the 38 patients who underwent TAVR via the transapical approach, 12 patients (31.6%) developed a conduction abnormality compared with 7 of 87 (8.0%) who received transfemoral TAVR (P = 0.002). The difference was driven by the greater incidence of left anterior hemiblock with the transapical approach.

Five patients (4%) developed an advanced atrioventricular block lasting more than 24 hours and required permanent pacing (placed 5 ± 1.41 days after the procedure). Of these, 2 had a right bundle branch block before the procedure. After 30 days, 2 patients still needed the pacemaker, and 1 patient had atrial fibrillation and right bundle branch block.

Clinical characteristics were similar in patients with and without new conduction defects except for higher rates of diabetes (P = 0.05) and peripheral vascular disease (P = 0.03) and more common use of ACE inhibitors or angiotensin II receptor blockers (P = 0.02) in patients with conduction defects. Baseline echocardiographic parameters also were similar.

Unanswered Questions

According to the authors, although theoretically the size of the predilation balloon or the implanted prosthesis could be important in the development of conduction disturbances, the current data do not support that hypothesis.

“Moreover, we could not demonstrate a relation between the occurrence of conduction defects and the ratio of the valve size to the echocardiographically determined size of the left ventricular outflow tract,” they write.

As to the observed relationship between an increase in left anterior hemiblock with the transapical approach, the authors say this suggests “the possibility that placement of the valve itself within the aortic valve ring by either approach threatens the proximal bundle branches but that the more distal branches of the left bundle branch, represented by the anterior fascicle, might more often be jeopardized by an approach to the valve from the ventricular side.”

Finally, Dr. Waksman and colleagues note that results from the current case series should not be generalized to TAVR procedures performed with the CoreValve (Medtronic, Minneapolis, MN) device, which have shown a higher rate of permanent pacemaker implantation.

 


Source:
Laynez A, Ben-Dor I, Barbash IM, et al. Frequency of conduction disturbances after Edwards SAPIEN percutaneous valve implantation. Am J Cardiol. 2012;Epub ahead of print.

 

 

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Disclosures
  • The paper contains no statement regarding conflicts of interest.

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