TAVR Valves Fail Fast in ESRD, Study Shows

PHOENIX -- End-stage renal disease (ESRD) patients often had rapid deterioration of their transcatheter aortic valve replacement (TAVR) prostheses, although reintervention wasn't common, a single-center study showed.

Structural valve degeneration occurred in 26.3% of patients over 4 years of follow-up, with average time to degeneration of 1.16 years and most occurring within the first 2 years, Samuel Gregerson, DO, of Henry Ford Hospital in Detroit, Michigan, reported at the Society for Cardiovascular Angiography and Interventions meeting here.

The mode of degeneration was aortic stenosis in 11.6% and aortic regurgitation in 15.8%.

"That's very high," compared with a rate of valve degeneration in the low single digits in the pivotal clinical trials, noted session moderator George Hanzel, MD, of Emory University in Atlanta.

But ESRD patients were excluded from the pivotal trials, as a group at high risk of complications and death.

"ESRD patients are predisposed to the development of calcific valvular disease," noted Gregerson. "The exact etiology is not overtly known, but it's suspected to be a heterogeneous driver, everything from calcium deposits to inflammation affecting the valve."

These data add to evidence from other small registries and Transcatheter Valve Therapies registry data on mortality and complication outcomes, Hanzel noted. "I think having more data, hopefully long-term, would help us maybe stratify which patients to be aggressive in and which not ... It's important to gather more data about this to figure out, could we put together risk models in dialysis patients in terms of who is it reasonable to treat and who's too sick?"

Gregerson's study included all 95 consecutive ESRD patients who had TAVR for aortic stenosis at his institution from 2012 to the present. In this group, more than 10 had valve events within 6 months of TAVR placement, with structural valve degeneration of stage 2S or 2R (moderate regurgitation or stenosis) as defined by the standards introduced by the VIVID group. Cases of infective endocarditis, valve thrombosis, and patient-prosthesis mismatch were excluded.

However, only 3.2% of patients had aortic valve reintervention, "in line with previously reported reintervention rates of 2-7% after SAVR [surgical aortic valve replacement]," Gregerson noted.

But while the rate of structural valve degeneration rose over with follow-up duration post-TAVR, the reintervention rate remained fairly stable.

Regarding that "large discrepancy," Gregerson said: "We postulated that it could be due to a few things. One, maybe the patient was too high-risk to undergo another intervention, so even though they had degeneration, reintervention was not sought. Two, on the flip side, actually they met degeneration criteria, but clinically, there wasn't a need for reintervention. And then third, if degeneration went unrecognized, then a reintervention wouldn't happen."

One factor in low reintervention rates, said Molly Szerlip, MD, of Baylor Scott & White The Heart Hospital-Plano in Texas, commenting from the audience at the presentation, could be that "a lot of these patients develop really bad peripheral vascular disease and there is no [vascular] access. And if you use any kind of secondary access or alternative access, they have a much higher mortality as well."

In-hospital and long-term major adverse cardiovascular event rates "were high" in the cohort, Gregerson acknowledged. "However, when looking at baseline STS [Society of Thoracic Surgeons] scores, these rates were close to expected."

He expressed hope that the retrospective cohort study "will help set up a prospective study where we can get more uniform follow-up at the 6-month, 1-year, and 2-year marks, because that was really a limiter in our data. It's all retrospective, so getting more uniform follow-up would be something we look for in a prospective study."

He noted a 5% attrition rate in the study over time.

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