Patient Traits Predict Need for Permanent Pacemaker After TAVR

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Patients undergoing transcatheter aortic valve replacement (TAVR) are more likely to need a permanent pacemaker if they are male, have abnormal baseline conduction, or experience atrioventricular block during the procedure, according to a meta-analysis published in the July 15, 2014, issue of the Journal of the American College of Cardiology.

Identification of TAVR candidates at high risk may help guide clinical decision making, though operators must also take into account the observed link between self-expandable devices and the need for permanent pacing, the authors say.

 
Several baseline and intraprocedural characteristics were associated with need for a permanent pacemaker after TAVR (table 1). 

Table 1. Predictors of Permanent Pacemaker After TAVR^a

Abbreviations: AV, atrioventricular; LA, left anterior; RBBB, right bundle branch block.

^a P < .01 for all.

Additionally, data from 9 studies showed a more than doubled risk of pacemaker need in those treated with CoreValve vs Sapien (RR 2.54; 95% CI 2.08-3.12). The same patient factors remained predictors of pacemaker implantation when considering only those who received CoreValve. Data on patients who received Sapien valves were limited and did not yield reliable predictors. 

There was a trend toward lower risk of permanent pacing with transfemoral vs subclavian access (RR 0.54; 95% CI 0.28-1.04; P = .07). Pacemaker need was not affected by baseline A-fib, LBBB, nor preserved LVEF.

Pacemakers Can Undermine Outcome  

“Identification of patients at increased risk of [permanent pacemaker] implantation after TAVR is of great clinical importance to prevent AV-block–related complications, including syncope, exercise intolerance, heart failure, and sudden death,” Dr. Windecker and colleagues write. “Patients with AV conduction disturbances after TAVR are prone to prolonged hospitalization and use of in-hospital continuous telemetry,” both of which increase cost, they say. 

Also, “there are concerns that patients who require [permanent pacing] may not derive the same benefit as patients without [pacemakers] because of loss of AV synchrony, lack of physiological rate control, and right ventricular stimulation,” they add. 

The authors observe that men more often need pacemakers than women because they have a higher burden of comorbidity and higher procedural risk overall. Men also receive larger bioprostheses, “which may have an impact on AV conduction,” they report.

“Future research should focus on collaborative efforts to validate previously identified predictors and to explore the role of others,” the authors conclude, adding that large-scale studies including different devices should concentrate on long-term outcomes.

‘Interesting Dynamic’ Between Devices, Risk  

In an accompanying editorial, Cynthia M. Tracy, MD, of George Washington University (Washington, DC), says that “it is not surprising that patients with preexisting [RBBB] or first-degree AV block would be at greater risk for heart block with device manipulation in the left ventricular outflow [tract]” since “the AV node and left bundle branch are located closer to the aortic root than previously believed.” 

Preexisting conduction abnormalities might also reasonably be expected at “a fairly high prevalence” in typical TAVR candidates such as elderly patients with calcific aortic stenosis, she adds. 

According to Dr. Tracy, there is an “interesting dynamic” between valve type and heart block. “It is conceivable that the full extent of potential risk may not be immediately apparent at the time of TAVR,” she writes, explaining that the duration of ‘watchful waiting’ before switching a patient from temporary to permanent pacing should depend on which valve the patient received. “The self-expanding [CoreValve] may not fully expand for 7 to 10 days,” she reports. 

Looking forward, development of future devices should focus on a lower profile and shorter height, Dr. Tracy writes, adding that modifying implantation technique could also reduce the need for permanent pacing. 

Ultimately, “these data underscore the importance of knowing the patient characteristics that confer risks for pacemaker implantation post-TAVR… and thereby taking steps to monitor patients appropriately,” she concludes. 

 Sources: 
1. Siontis GCM, Jüni P, Pilgrim T, et al. Predictors of permanent pacemaker implantation in patients with severe aortic stenosis undergoing TAVR: a meta-analysis. J Am Coll Cardiol. 2014;64:129-140.

2. Tracy CM. Pacemaker after transcatheter aortic valve replacement: unexpected, but not infrequent outcome [editorial]. J Am Coll Cardiol. 2014;64:141-143.

 
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