Author + information
- ↵∗Address for correspondence:
Dr. George Bayliss, Rhode Island Hospital and Alpert Medical School, Brown University, Medicine, Renal Division, APC 9, Rhode Island Hospital, 593 Eddy Street, Providence, Rhode Island 02903.
Patients with end-stage renal disease (ESRD) on dialysis have a high risk of developing aortic stenosis. They tend to develop the disease earlier than the nondialysis population (1) and at a faster pace (2). Mortality is high for dialysis patients who undergo surgical aortic valve repair (3). That leaves aortic valvuloplasty and transcatheter aortic valve replacement as the only other possible interventions. But, as is too often the case with patients on dialysis, there is little data to answer the question of whether transcatheter aortic valve replacement (TAVR) is a safer alternative, because dialysis patients were excluded from the initial trials and small trials offered mixed results (4).
To provide data, in this issue of the Journal, Szerlip et al. (5) sought to determine whether TAVR offered a safer alternative to surgical valve repair for dialysis patients with aortic stenosis (AS). The results of their retrospective analysis of registry data are sobering and should give pause to physicians considering TAVR as an alternative to surgical repair for their dialysis patients with AS.
They reviewed data on 3,053 patients with ESRD on dialysis who were among the first 72,631 patients with severe AS treated with TAVR enrolled in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) TVT (Transcatheter Valve Therapies) registry. ESRD patients, who represented only 4.2% of the total, were compared with patients who were not on dialysis for demographics, risk factors, and outcomes. ESRD patients were younger, mostly male, and predominantly African American. Medically, ESRD patients were more likely to have diabetes, hypertension, history of myocardial infection, peripheral vascular disease, and worse heart failure symptoms than the non-ESRD patients. There was no difference between the 2 groups in terms of previous coronary revascularization, stroke, or atrial fibrillation. Dialysis patients, who were more likely to be considered too high risk for surgical repair, were significantly more likely to need the procedure urgently or under emergency circumstance.
Dialysis patients had a significantly higher in-hospital mortality than nondialysis patients (5.1% vs. 3.4%) and had a significantly higher 1-year post-procedure mortality rate (36.8% vs. 18.7%). The ratio of observed to expected mortality for dialysis patients was lower than expected (0.32 vs. 0.44). But the authors noted that this is the case only because the numerator represents in-hospital mortality while the denominator represents expected 30-day mortality. Dialysis patients had a similar rate of major vascular complications (4.5% vs. 4.6%), as did nondialysis patients, but were more likely to need alternative access to the standard femoral artery approach and have a higher rate of major bleeding (1.4%, vs. 1.0%). Interestingly, there was no increased risk of stroke.
The data on in-hospital mortality are similar to those by Gupta et al. (6), who found that inpatient mortality was higher for patients with chronic kidney disease (CKD) or ESRD undergoing TAVR than for patients without CKD, with a relative risk of 1.39 and 2.58, respectively. CKD and ESRD patients undergoing TAVR had a higher risk of the composite outcome of death, myocardial infarction, or stroke than those without CKD (6).
It is not surprising that the relative risk of death at 1 year is higher for dialysis patients undergoing TAVR, because it is already high for patients with reduced kidney function. Hansen et al. (7) looked at data from the same STS/ACC TVT registry and found that pre-existing CKD, with an estimated glomerular filtration rate (eGFR) below 60 ml/min/1.73 m2 (stage III) was associated with a higher risk of death, and mortality increased significantly when the eGFR fell below 30 ml/min/1.73 m2 (stage IV CKD). They concluded that that hazard ratio for a composite of death and need for dialysis at 30 days was 1.43 in stage III CKD, 2.986 in stage IV CKD, and 6.734 in stage V CKD. At 1 year, the hazard ratios were 1.318, 2.187, and 4.274, respectively. Interestingly, the hazard ratio for death alone in stage V was not significant at 30 days or 1 year, but the authors argued that this may be due to relatively small numbers.
Is ESRD a marker of futility for TAVR? Some have argued not (8). One small study of 85 dialysis patients with severe AS showed improved 1-year mortality for dialysis patients with surgical or transcatheter aortic valve repair compared with balloon aortic valvuloplasty (9).
Szerlip et al. (5) rightly note that the mortality risk of TAVR in ESRD patients increases with the number of comorbid conditions, while the need for alternative access to the femoral approach increases the risk of vascular access complications. Thus, they suggest the need to carefully select patients. The message one may take from their work is that TAVR is a high-risk procedure for anyone with ESRD on dialysis or even approaching the need for dialysis.
In deciding whether to send a dialysis patient for a TAVR, physicians need to know more than the outcome for ESRD patients compared to patients without ESRD. What separates dialysis patients who undergo successful TAVR from those who do not? What are the alternatives and outcomes for dialysis patients with critical AS who do not receive a TAVR compared to those who do? These questions are outside the scope of this paper, but knowing how to answer them is crucial.
The subgroup that would conceivably benefit is the one with few other comorbidities and in whom intervention is made just in time. Patients with ESRD already have a fatal disease, but are kept alive by an artificial organ. Kidney transplantation is the only renal replacement alternative to dialysis. Dialysis patients with critical AS are unlikely to be candidates for kidney transplantation before repair. Transplantation after TAVR is very rare (10). If valve repair improved symptoms enough to allow a transplant to go forward, then there certainly would be value.
The third option for a dialysis patient with severe AS is 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. As it stands, the data provided by Szerlip et al. (5) show that TAVR is a risky procedure for dialysis patients with AS.
Although ESRD may not be an absolute contraindication to TAVR, just because we can replace the valve does not mean we should in every dialysis patient with severe AS. More data is needed to identify a probably small subset of ESRD patients with AS who are too sick to undergo surgical repair, yet who would benefit from a TAVR. Even then, those patients and their families need to know that the procedure carries high risk and may, at best, only buy a little more time.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Bayliss has reported that he has no relationships relevant to the contents of this paper to disclose.
- 2019 American College of Cardiology Foundation
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