麻豆传媒

CHICAGO -- Newer devices don't mean that the maturing transcatheter aortic valve replacement (TAVR) field has completely solved its problem with conduction disturbances requiring permanent pacemaker (PPM) implantation, according to an updated analysis from the TVT Registry.

The incidence of in-hospital and 30-day PPM placement fell from 12.8% in 2016 to 9.7% in 2020, for an overall rate of 11.3% across the nearly 700 hospitals in the U.S. that performed TAVR in more than 250,000 people during this period, reported Amit Vora, MD, MPH, of UPMC Heart and Vascular Institute in Harrisburg, Pennsylvania.

The decrease in PPM rates over time may be attributed to newer-generation technology, novel implantation techniques, and operators progressing in their learning curves.

Although variation across sites decreased somewhat, there was enough of it that PPM rates ranged from 0% to 36%, Vora said in a presentation at the Transcatheter Valve Therapeutics (TVT) conference hosted by the Cardiovascular Research Foundation.

He emphasized that a pacemaker implant is "not benign" as it opens the door to complications, higher cost, and poor outcomes.

"As TAVR becomes the dominant therapy across risk strata, the potential risk of a pacemaker can have long-term implications," he said, adding that pacemakers can have an outsized impact on the increasingly younger, lower-risk TAVR patients who may not have persistent pacing requirements.

Vora reported that his group observed wide variation in PPMs when taking into account annualized TAVR volumes. Outlier sites were 34 hospitals above the 95% percentile and 28 below the 5th percentile, adjusted for valve type.

Ultimately, two similar patients would have had a 40% difference in their odds of needing a PPM after TAVR at one site versus another, according to Vora.

Nevertheless, it's clear that low rates are achievable with both CoreValve and Sapien platforms available commercially in the country, he said.

TVT panelist Tom Cahill, MD, PhD, of New York-Presbyterian Hospital/Columbia University Irving Medical Center in New York City, said he was struck by how much variability remains in practice between centers. "How can we standardize and bring everyone to the level of the best?" he asked.

Vora suggested the importance of high-performing centers disseminating best practices to lower-performing ones. Emerging techniques to mitigate PPM risk include cusp overlap and the Cleveland Clinic group's high deployment technique.

Session discussant Tamim Nazif, MD, also of New York-Presbyterian and Columbia University, added that there are recent reports that membranous septum length and calcium burden and location are predictors of conduction disturbances after TAVR. He recommended "careful attention to modifiable predictors of conduction disturbances and safe, appropriate post-TAVR patient management."

But "until we get the evidence, it's going to be tough," said John Forrest, MD, of Yale New Haven Hospital. He shared his occasional experiences with patients who get TAVR only to die 20 days or 45 days later at home. "That's what keeps me up, that we don't know what happened," he said.

During his report, Vora noted that the decrease in PPM rates over time was "much more pronounced" with current-generation self-expanding valves than balloon-expandable valves. Nevertheless, from approximately February 2019 to February 2020, the PPM rates were 15.6% and 9.29%, respectively, between these two device types, apparently favoring the balloon-expandable ones.

Higher annual TAVR site volumes did not correlate with lower PPM after adjustment.

However, higher operator case numbers did. The learning curve was more obvious for self-expanding valves, for which it took an operator around 100 procedures to achieve a consistently low PPM rate, Vora found.

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