Permanent Pacemakers After TAVR: Model Helps Predict Individual Patient Risk With Sapien 3

A handful of nonmodifiable anatomic factors could help further pinpoint patients at high risk for needing a permanent pacemaker after TAVR with the Sapien 3 valve. In a single-center study, the risk factors were validated and used to form the basis of a model that attempts to refine prediction beyond implantation depth.

“The message is that each patient’s risk profile is different,” Hasan Jilaihawi, MD (NYU Langone Medical Center, New York, NY), the study’s senior author, told TCTMD. “Our risk model is basically a precursor to how we can modify patient care. The ultimate final step would be to know with utmost certainty that this patient is going to need a pacemaker and therefore preemptively put a pacemaker in. What we’ve tried to do is to develop a very robust predictive algorithm specific to [Sapien 3] that could be used as a framework for other devices as well . . . because each of these devices has a different spectrum of risk.”

While research indicates that the rate of permanent pacemaker is lower with the Sapien 3 (Edwards Lifesciences) than with first-generation TAVR devices, at about 10.2%, it is higher than both the original Sapien and the Sapien XT models (3.8% and 8.5%, respectively).

Cracking the Risk Factor Code

For the current study, published today in JACC: Cardiovascular Imaging, and led by Yoshio Maeno, MD, PhD (Cedars-Sinai Heart Institute, Los Angeles, CA), the researchers studied 240 patients who underwent TAVR with Sapien 3 between November 2013 and December 2015 at their institution. Following the procedure, 14.6% needed a permanent pacemaker, most for complete heart block.

On multivariate analysis, right-bundle branch block (RBBB), shorter membranous septum length, and non-coronary cusp device landing zone calcium volume all were independent predictors of needing a permanent pacemaker after the procedure. Neither baseline heart rate nor degree of oversizing was associated with new permanent pacemaker implantation.

Combining the three risk factors in their model with device depth resulted in a pre- and post-TAVR predictive probability area under the curve of 0.916, with sensitivity of 94.3%, specificity of 83.8%, positive predictive value of 49.3%, and negative predictive value of 98.8%. The model was validated in a cohort of 105 consecutive patients undergoing TAVR with Sapien 3 from January 2016 through April 2016, and yielded a consistent predictive pattern.

“We’ve pretty much cracked it with this model,” Jilaihawi observed. “The next step is using it clinically. What I think this paper helps us to further understand is that primarily the need for pacemaker after TAVR is anatomical. It’s about the interaction of the device with anatomy.”

Another important message from the paper, Jilaihawi added, is the emphasis that even in the presence of RBBB, landing the Sapien 3 valve as high as possible may eliminate need for permanent pacemaker in some patients.

“This is something I’ve seen born out in my own clinical practice,” he said. “In the past you would see someone with RBBB and you were almost guaranteed that they would need a pacemaker, but that’s not the case and even at follow-up they aren’t having late heart block, so this concept of landing as high as possible is clearly important.”

In an editorial accompanying the study, Samir R. Kapadia, MD (Cleveland Clinic Foundation, OH), and colleagues note that there is “tremendous variability” in the use of permanent pacemakers after TAVR. The risk factors identified in the study, they say, make sense in relation to the anatomy of the conduction system since valve implantation that overlaps the distal membranous septum may affect both the right and left bundles and result in complete heart block. Similarly, substantial calcification at the non-coronary cusp device landing zone may “exert uneven pressure either at the level of the [membranous septum] or at the left bundle that runs on the left ventricular side of the muscular septum,” they observe.

Kapadia and colleagues also point out that while predisposing anatomic features are uncontrollable, they “may inform the need for continued observation for conduction deficit. Ultimately, the only variable which can be controlled at time of procedure is the depth of implantation, and the current analysis demonstrates that [membranous septum] height helps to define the degree of ‘freedom’ for this depth.”

Moving Toward Personalized Medicine

The emergence of predictive risk models is of particular interest as TAVR moves into lower-risk patient populations. To TCTMD, Jilaihawi said adding these anatomical factors to other individual risk factors that a patient has allows the needle to move toward more personalized medicine.

“By knowing all the anatomical risks and sharing them with the patient you have more options. It may be that a patient doesn’t mind the risk of pacemaker . . . or it could be that they fear the complications of having to have a pacemaker,” he observed.

However, additional research is needed to understand the risk factors in the context of devices other than Sapien 3, as well as in populations beyond this single-center cohort.

“You can’t move this model from one device to another seamlessly. We have to better understand how [it] is applicable to [Medtronic’s] Evolut and the next generation [of devices],” Jilaihawi noted. “But the goal is that instead of telling patients that their risk of pacemaker is between 5% and 15% with Sapien and perhaps higher with Evolut, we can instead [quote an individual number] in a reliable fashion that isn’t just a blanket statistic for everyone undergoing TAVR.”