Transcatheter aortic-valve replacement (TAVR) offers an alternative to surgical repair in patients with end-stage renal disease (ESRD) but carries substantial risks of its own, a large registry study confirms.
Dialysis was one of the strongest predictors of 1-year mortality (adjusted hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.17 – 1.41) in the study, which was published June 11 in the Journal of the American College of Cardiology.
“Although procedural outcomes appear acceptable, a 1-year survival in only one-half of the treated patients raises concerns regarding the benefit of treatment in this patient population,” write Molly Szerlip, MD, Baylor Scott and White Health, Plano, Texas, and colleagues. “Further analysis is necessary to delineate the patients with ESRD who are likely to have favorable procedural and functional outcomes.”
Determining who these patients are is something the team consistently wrestles with in clinical practice, Szerlip observed.
“When we see dialysis patients, we really take into account why they are on dialysis,” she told theheart.org | Medscape Cardiology. “The person who has polycystic kidney disease and is on dialysis is very different than the person who has diabetes, peripheral vascular disease, and hypertension. So we really look at the cause of their dialysis and try to assess what the 1- or 2-year mortality is without aortic stenosis.”
Although small series have shown mostly worse outcomes in patients with ESRD and chronic kidney disease, the benefit of TAVR remains unclear because patients with ESRD have been excluded from pivotal TAVR randomized trials.
To examine how TAVR is affecting outcomes including mortality, the investigators examined the first 72,631 participants with severe symptomatic aortic stenosis in the Transcatheter Valve Therapies registry from November 2011 to June 2016.
The 3,053 patients with ESRD (4.3%) were younger (78 years vs 84 years), but more likely to have more baseline comorbidities leading to a higher Society of Thoracic Surgeons–predicted risk of mortality (14.4% vs 6.8%).
Most procedures were elective, although the ESRD group had a higher prevalence of urgent procedures (17.2% vs 8.9%; P < .01). A transfemoral approach was less common in the ESRD group (76.4% vs 78.4%; P = .01), although device success was similar (92.4% vs 93.0%; P = .17).
Procedural complications led to longer hospital stays for patients with ESRD (mean 6 days vs 5 days; P < .001). VARC major bleeding events also were more common in those with vs without ESRD (1.4% vs 1.0%; P = .03), although there were no differences in vascular site complications, unplanned vascular procedures, and stroke.
The ESRD group had significantly higher in-hospital mortality (5.1% vs 3.4%; P < .001) but the observed/expected mortality rate was lower (0.32 vs 0.44; P < .01), with the authors arguing that use of in-hospital rather than the more standard 30-day mortality may have led to an artificially low O:E ratio.
Building on prior research reporting a progressive mortality risk as renal function worsens, the presence of renal dysfunction incrementally increased the risk for 30-day, 6-month, and 1-year mortality, the authors report. When patients were stratified by serum creatinine, 1-year mortality rates were higher in patients on dialysis compared with those with a creatinine of at least 2 mg/dL or less than 2 mg/dL (36.8% vs 30.6% vs 17.9%; P < .01).
The message from this study is that “TAVR is a high-risk procedure for anyone with ESRD on dialysis or even approaching the need for dialysis,” George Bayliss, MD, Brown University, Providence, Rhode Island, writes in an accompanying editorial.
Questions outside the scope of the paper include (1) what separates dialysis patients who undergo successful TAVR from those who do not; and (2) what the alternatives and outcomes are for dialysis patients with critical aortic stenosis who don’t receive TAVR vs those who do, he noted.
If valve repair improves symptoms enough to allow a kidney transplantation to go forward, then there certainly would be value, Bayliss writes. However, another option for these patients would be to continue medical management.
“If there is no significant difference in outcomes with careful selection of ESRD patients or between aggressive care (TAVR) and conservative care (no TAVR), then it would be reasonable to recommend against the procedure for a patient on dialysis and instead shift the discussion to staying comfortable in whatever time he or she has left,” Bayliss suggests.
Asked about the remark, Szerlip said. “I hate to say it, but this is a very expensive technology. So are we using it for morbidity reasons or for mortality? Can we afford to use TAVR as, you know, comfort care? So, I think they bring up a very good question and that’s kind of why we did the study.”
Commenting further, she said, “Again, when we look at end-stage renal disease patients, we look at why they have end-stage renal disease to help us. If they’re going to live longer than 2 years, then we’d do it but if they’re not, it does beg the question, should we be doing this?”
Szerlip said there’s no reason to think the results would be different with newer-generation TAVR valves. She also joined Bayliss in saying more research is needed, and called for dialysis patients to be allowed in randomized trials as a separate cohort, so “we can get a true idea of how these people do.”
Although patients with ESRD made up less than 5% of the cohort, the issue will become increasingly important because as the population ages, there will be more kidney disease and more patients living longer with diabetes and hypertension. “We’re going to have more patients on dialysis,” observed Szerlip.
Szerlip has served as a speaker for Edwards Lifesciences and Medtronic. Her coauthors’ conflicts of interest are listed in the paper. Bayliss has disclosed no relevant financial relationships.