NEW YORK (Reuters Health) – Kidney function in patients with moderate or severe proteinuria may improve along with cardiac output after transcatheter aortic valve implantation (TAVI), an exploratory study suggests.
Dr. Jorn Brouwer of St. Antonius Hospital in Neuwegein, the Netherlands and colleagues conducted a prespecified substudy of the POPular TAVI trial, which investigated the addition of clopidogrel to aspirin or oral anticoagulants after TAVI.
As reported in Circulation: Cardiovascular Interventions, plasma and midstream urine specimens of 133 patients were collected on the day of the procedure and at six, 24, 48, and 72 hours after TAVI.
Proteinuria was quantified using the albumin/creatinine ratio when albumin was measured and protein/creatinine ratio when total protein was measured, and classified as none-to-mild and moderate-to-severe.
Most patients (81.9%), had moderate or severe proteinuria at baseline; the mean serum creatinine and eGFR were 101.7 micromol/l and 60.4 mL/min per 1.73 m2, respectively.
The rate of moderate and severe proteinuria decreased over time from 81.9% at baseline to 61.5% at 72 hours. Most patients (86.1%) had a stable eGFR at 72 hours; 10.2% had acute kidney recovery; and 3.7% had acute kidney injury.
By contrast, the mean level of serum creatinine, and corresponding eGFR, did not change significantly over time.
The authors conclude, “The overall rate of proteinuria in this study decreased over time (absolute reduction of moderate and severe proteinuria of 20.4 percentage points), which suggests that improving the cardiac output with TAVI reduces proteinuria within days after TAVI.”
Dr. Brouwer did not respond to requests for a comment; however, three experts commented in emails to Reuters Health.
Dr. Azeem Latib, Director, Interventional Cardiology, and Medical Director, Structural Heart Interventions at Montefiore Health System in New York City, said, “Our main concern has always been about not causing renal injury, because these patients are elderly with reduced renal function, and the actual TAVR procedure can also negatively impact renal function – mostly because of hypotension and the contrast used during the procedure.”
“Anecdotally, however, all of us have also seen improvement in renal function after TAVR, which we attributed to the increase in cardiac output,” he said.
“This study is unique because it suggests that there may be more subtle injury to the kidney from poor perfusion that is related to the decreased blood flow coming out of the heart because of the stenotic aortic valve,” he noted. “This is very interesting, exciting and plausible. We may now have an easy and cheap marker to evaluate improvement of renal function and cardiac output after TAVR.”
Nonetheless, he added, “This is a small substudy of a larger study that was designed to answer a different question. As this is only a research letter, we are lacking very important information. It would be important to understand the prevalence of diseases associated with kidney disease and proteinuria, such as hypertension, diabetes, etc. Also, it would be important to understand if there were predictors of the improvement in proteinuria.”
Dr. Sahil Khera, Interventional Director of the Structural Heart Program at The Mount Sinai Hospital in New York City, said, “Patients with severe aortic stenosis often have underlying type II cardio renal syndrome due to low cardiac output. This is an interesting exploratory analysis of the immediate post-operative effects of relief of outflow obstruction.”
“What I would like to see in the future studies is how this translates to clinical utility,” he said. “Two important questions are: Does improvement in proteinuria translate to better mid- and long-term outcomes? And, are patients without a change in proteinuria post-TAVR at a higher risk of readmissions due to acute kidney injury or congestive heart failure, and (do they) need closer monitoring?”
Dr. Sanjiv Patel, an interventional cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, California, added, “As is the case with the vast majority of conducted studies, further assessment is needed with a larger number of patients. However, we will likely continue to find that renal function does improve following TAVI.”
SOURCE: https://bit.ly/2U4nJ7O Circulation: Cardiovascular Interventions, online June 10, 2021.
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