BNP Levels May Not Be Effective Prognostic Tool for Patients With Cardiogenic Shock Using VADs

B-type natriuretic peptide (BNP) has long been considered a crucial biomarker in the diagnosis and prognosis of heart failure (HF). However, research conducted by physician-scientists at the University of Alabama at Birmingham's Marnix E. Heersink School of Medicine has cast doubt on its effectiveness as a prognostic tool for patients using ventricular assist devices (VADs).

Their findings, recently published in the American Journal of Cardiology, reveal that while BNP levels remain high in patients with end-stage HF with cardiogenic shock, these levels lose their prognostic value in patients who use VADs.

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BNP, a marker present in the blood, is widely recognized for reflecting the severity of cardiac dysfunction and is often linked to adverse clinical outcomes in patients with HF. In this study, researchers focused on patients with end-stage HF and cardiogenic shock—a condition where the heart's pumping ability is severely impaired, leading to insufficient blood circulation in the body.

Due to a lack of comprehensive data on this specific subset of patients, the relationship between BNP levels and their prognostic significance had not been well-defined until now.

“End-stage heart failure represents the end of the clinical spectrum of heart failure where patients require a heart transplant or a device like a VAD that assists with the pumping function of the heart,” explained Naman S. Shetty, MD, clinical research fellow in the UAB Division of Cardiovascular Disease and lead author of the study. “Considering that there is a shortage of hearts for transplantation, there is a significant increase in the number of patients being implanted with a VAD.”

He further explained that predicting outcomes following VAD implantation is of paramount importance for efficiently allocating health care resources and providing optimal patient care. Typically, a combination of clinical evaluations, medical imaging, and biomarker data is used to assess patient suitability and predict post-implantation outcomes. Because of these factors, there is a critical need for a definitive biomarker to aid health care decisions for patients with end-stage HF.

Shetty and his research team analyzed data from approximately 7000 VAD recipients enrolled in the INTERMACS database, a comprehensive repository of clinical information on VAD recipients across the United States hosted at UAB. The study found that BNP levels among patients with end-stage HF and cardiogenic shock were similar to those in patients in earlier stages of HF.

It was previously hypothesized that in end-stage HF, the heart's capacity to produce and release BNP might become impaired due to the weakening of the heart muscle and overall cardiovascular dysfunction.

However, contrary to this belief, this study provides evidence that refutes this assumption.

“Furthermore, the study showed that factors influencing BNP levels in healthy individuals continued to act even in patients with end-stage heart failure with cardiogenic shock, said Pankaj Arora, MD, associate professor in the UAB Division of Cardiovascular Disease and senior author of the manuscript. “Previously, we have shown that BNP was lower in males and Black individuals compared with their counterparts. We noted a similar pattern even in end-stage heart failure with cardiogenic shock.”

Arora urged future research to explore the prognostic potential of biomarkers representing alternative pathophysiological pathways, such as fibrosis, to guide clinical decisions in end-stage heart failure. He also suggested that machine learning models incorporating multiple factors could be developed and implemented to estimate the mortality risk in this patient population.

“Currently, BNP levels are being routinely measured in patients with end-stage heart failure,” said Arora. “Given the lack of prognostic value of this marker, the study questions the need for this practice. Machine learning models that incorporate several factors to estimate the risk of mortality may be developed and implemented in this patient population to guide clinical decision-making.”

Reference

Shetty NS, Patel N, Parcha V, et al. Clinical correlates and prognostic value of B-type natriuretic peptide in left ventricular assist device recipients with cardiogenic shock: insights from INTERMACS. Am J Cardiol. 2023;205:451-453. doi:10.1016/j.amjcard.2023.07.177