Christchurch Heart Institute

The Christchurch Heart Institute (CHI) is a research centre based at the University of Otago, Christchurch, New Zealand. CHI was initially named Christchurch Cardio- endocrine Research Group by Professor Richards when he recruited researchers from multiple disciplines to form a cohesive group in the 1990s. Over the past 35 years, CHI has been internationally recognised for its discovery and validation of B-type Natriuretic Peptide (BNP) and NT-proBNP (NT-proBNP) as diagnostic and prognostic biomarkers for heart failure, which have since become standard tools used in clinical practice worldwide. This discovery led to faster and more accurate diagnosis of heart failure, resulting in shorter hospital stays, fewer readmissions, and a reduction in mortality rates.

Heart Failure

Heart failure is a chronic disease that occurs when the heart muscle doesn’t pump blood as well as it should. When this happens, blood often backs up, and fluid can accumulate in the lungs, causing shortness of breath. Heart failure develops over time as the heart is damaged or placed under strain. To compensate, the heart may enlarge, thicken, or beat faster; however, these changes often exacerbate the condition. Heart failure usually develops after health conditions, such as coronary artery disease, cardiomyopathy, high blood pressure and congenital heart defects. Early diagnosis improves the chance of managing it with medications and lifestyle changes. It cannot be fully cured, but its symptoms can be managed and improved with treatment. It is the leading cause of hospitalisation in adults over 65. More than 180,000 people in New Zealand are currently living with heart disease. During 1997, 7472 people died caused by ischaemic heart diseases in New Zealand. ³

Christchurch Heart Institute’s research on BNP as a biomarker for heart failure

BNP is a protein hormone that helps to regulate blood circulation throughout the body. It is secreted within the heart ventricles in response to stretching caused by increased ventricular blood volume. BNP was first discovered in 1988 by Japanese scientists. Soon after, CHI researchers developed a method of measuring BNP in blood plasma. CHI research found that patients with congestive heart failure and recent myocardial infarction (heart failure), had higher levels of BNP in the blood compared to healthy individuals. In heart failure patients, blood tests show high BNP levels, but most of it is an inactive precursor, not the active hormone. Heart failure patients have both active BNP and its larger inactive precursor; the precursor is almost twice as abundant. In contrast, healthy patients only have the active BNP form. This means that high BNP levels in heart failure are mostly caused by a buildup of the precursor form. When the heart is under extra pressure, it releases proBNP into the blood. This splits into BNP and an inactive fragment. BNP helps relax blood vessels and makes the body remove more salt and water, which lowers blood volume and eases the strain on the heart.

Through further investigation into natriuretic peptide isoforms and refinement of the testing method, the team proposed measuring NT-proBNP (the inactive fragment split from the proBNP) as a potential biomarker for heart failure. Their groundbreaking work led to the development of the NT-proBNP diagnostic test. CHI researchers began trialling BNP testing for patients presenting with breathlessness in the Christchurch emergency department in 1993. Dr. Mark Davis and the team found that patients with heart failure had significantly elevated BNP levels compared to those without cardiac conditions.

Biomarkers That Saved Lives: The Global Impact of CHI’s Work on BNP and NT-proBNP

In 2004, CHI researchers and Professor James Januzzi from the Harvard Medical School formed the International Collaborative of NT-proBNP research study. The study confirmed that NT-proBNP testing was highly valuable for diagnosing acute heart failure and predicting outcomes in patients with shortness of breath. CHI also identified cut-off values that are now embedded in international guidelines, proving NT-proBNP as a key tool in heart failure management

In 2014, a global meta-analysis of nine randomised clinical trials with 2,000 patients led by a CHI researcher confirmed that using BNP or NT-proBNP as a clinical guide significantly reduced all-cause mortality in patients under 75 years old and led to fewer hospitalisations related to heart failure and cardiovascular disease.² Compared to standard care, natriuretic peptide-guided therapy reduced overall deaths by 38%. These biomarkers are not only valuable for diagnosis but also essential for guiding effective, life-saving treatment worldwide.

‍

In 2025, Our Health Journeys continued our partnership with Saint Kentigern College in Auckland to challenge a number of students to conduct research into an aspect of the medical history of Aotearoa New Zealand. The students, ranging from Years 8-13, produced their research in written, oral, or video format and the top projects were chosen for publication to Our Health Journeys.