BNP Levels Help Predict Negative Outcomes Following TAVR

July 15, 2020

An analysis of major trials examining TAVR suggests BNP levels could help predict patients at a greater risk of negative outcomes.

New research suggests elevated B-type natriuretic peptide (BNP) levels could help predict risk of adverse outcomes following transcatheter aortic valve replacement.

Results of the analysis suggest every 1 unit increase in BNP ratio at 30 days was associated with an 11% increase in risk of all-cause mortality and a 16% increase in risk of cardiovascular death, even after adjustment for confounding factors.

While transcatheter aortic valve replacement has revolutionized care of patients with aortic stenosis, clinicians still lack effective predictors of adverse events for patients undergoing such procedures. With this in mind, investigators sought to determine whether elevated BNP levels after valve replacement could serve as a predictor for increased mortality and hospitalization risk.

Using the PARTNER IIA, PARTNER IIB, AND SAPIEN 3 studies, investigator identified a cohort of patients with severe symptomatic aortic stenosis at intermediate, high, or prohibitive risk for aortic valve replacement. Using the data from these studies, investigators obtained BNP levels from baseline, discharge, 30 days, and 1-year post-TAVR.

Of note, BNP ratio was calculated using measured BNP level divided by the upper limit of normal for the assay used. Additionally, landmark analyses evaluated outcomes of interest out to 2 years. The primary outcomes of interest in the trial were ill-use death, cardiovascular death, hospitalization, and the combined end point of cardiovascular death or hospitalization.

In total, 3391 patients were identified for inclusion in the study. The mean age of this group was 82 (7.5) years and 58.1% were male. Of the 3391 subjects, 859 were obtained from PARTNER IIA, 1000 were obtained from PARTNER IIB, 594 were obtained from the SAPIEN 3 intermediate-risk registry, and 938 were obtained from from the SAPIEN 3 high-risk registry.

In regard to data on BNP levels, 3018 had data related to baseline levels, 2836 had data related to levels at discharge, 2128 had data related to levels at 30 days, and 2316 had data related to levels at 1 year. Investigators pointed out patients in higher quartile of 30-day BNP ratio had more comorbidities, higher Society of Thoracic Surgeons scores, worse left ventricular function, and a lower rate of transfemoral transcatheter aortic valve replacement.

Results of the analysis indicated every 1-point increase in BNP ratio at 30 days, which was equivalent to an increase of 100 pg/mL in BNP, was associated with an increased hazard of all-cause death, cardiovascular death (aHR, 1.16; 95% CI, 1.11-1.21), and rehospitalization (aHR, 1.08; 95% CI, 1.03-1.14) between 30 days and 2 years post-procedure.

In patients with a BNP ratio of 2 or greater at discharge, each 1-point decrease in BNP ratio between discharged and 30 days was associated with an 8% decrease in hazard of all-cause mortality between 30 days and 2 years post-procedure (aHR, 0.92; 95% CI, 0.88-0.96).

In a related editorial, JAMA Cardiology editors Robert Bonow, MD, and Patrick O’Gara, MD, underline the potential prognostic values of BNP levels but cautioned against overinterpretation without considering limitations of the analysis.

“Interpretation of the findings from O’Leary et al must account for several limitations, including incomplete BNP sampling, nonstandardized BNP assays, survival bias, and generalizability. Use of the BNP ratio to overcome the lack of assay standardization was an acknowledged compromise. Prospective studies using uniform methodology would be the next step to determine whether these data can be applied more broadly,” wrote the pair.

This study, “Association of Natriuretic Peptide Levels After Transcatheter Aortic Valve Replacement With Subsequent Clinical Outcomes,” was published in JAMA Cardiology.