NEW YORK (Reuters Health) – Transcatheter aortic-valve replacement (TAVR) is associated with an improvement in kidney function, which in turn is tied to lower two-year mortality, according to a new retrospective study.
“These findings validate the conclusions of prior randomized clinical trials in a nonrandomized, all-comers setting,” writes the author of a commentary published with the study in JAMA Network Open.
And they “suggest that TAVR can arrest cardiorenal syndrome and lead to long-term improved kidney function in patients with” chronic kidney disease (CKD), notes Dr. Benjamin Galper of Mid-Atlantic Permanente Medical Group, in McLean, Virginia.
For the new study, Dr. Guy Witberg of Rabin Medical Center in Petach Tikva, Israel, and his colleagues pulled data on all patients who underwent TAVR at their institution between 2008 and 2019.
For each patient, they calculated the estimated glomerular filtration rate (eGFR), first at a baseline defined as less than two days before the procedure, then another two days afterward, again at discharge and finally one month after TAVR. Mortality was assessed at two years.
Significant improvement or worsening of a patient’s renal function was defined as any value greater than or equal to a 10% change in their eGFR at the one-month mark.
“Three months would have given a more accurate assessment,” Dr. Witberg told Reuters Health by email, “but we also need to consider that the longer we wait to assess the change in renal function we introduce more survival bias.”
Patients who died within that 3-month timeframe, for example, would not be included in such a later assessment, Dr. Witberg said. “And many of these are probably those with deterioration in renal function post-TAVR.”
The cohort was composed of low-to-intermediate-risk patients, half were women and the mean age was 82 years. The patients’ mean Society of Thoracic Surgery (STS) score was 5.2% and their mean eGFR 65.1 mL/min/1.73 m2.
Patients who required chronic hemodialysis in the year before their TAVR, as well as those who did not survive one month after TAVR, were among those excluded from the analysis. Patients whose serum creatinine measurements were unavailable at the 48-hour and one-month marks were also excluded.
Of the 894 TAVR patients included, renal function had improved for 36.8% and either improved or remained stable for 80.6% at the one-month point following their procedure.
Among this group, patients who showed a resolution of their chronic kidney disease status (defined as eGFR improvement to >60 mL/min/1.73m2 after TAVR) had a similar two-year mortality as those whose baseline eGFR was greater than 60 mL/min/1.73m2.
One hundred and fifteen patients (11.1%) suffered acute kidney injury within the first 48 hours after TAVR; 73 of those cases (63.5%) had resolved by hospital discharge. These patients, however, had more than twice the mortality risk at two years compared with patients who did not experience AKI, with significant risk regardless of the timing of their AKI resolution.
Compared with all other patients, those whose kidney function had deteriorated by their one-month follow-up had a two-fold increased risk of death at two years after multivariate adjustment (hazard ratio, 2.16; P=0.04), with a significant 19.3% mortality increase for every 10% reduction in eGFR.
Only five patients (0.97%) progressed to stage-5 CKD one month after undergoing TAVR.
Given the many advancements in TAVR over the decade under review, Dr. Witberg and his colleagues also analyzed the data by date of the procedures.
“There was no association between the time period and the change in renal function post TAVR,” the researchers told Reuters Health.
Dr. John Blair, a University of Chicago Medicine cardiologist who was not involved in this study, said the findings were consistent with earlier research.
“The strengths of this paper come from the large sample size and good follow-up on these patients,” Dr. Blair told Reuters Health by email. “It is a single-center study so broader application to other hospital systems or patient populations should be done with caution.”
SOURCE: https://bit.ly/3dlRF5s JAMA Network Open, online March 26, 2021.
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