MedicalResearch.com Interview with:
Professor Kazem Rahimi, FRCP MD DM MSc FES
Deputy Director, The George Institute for Global Health UK
Associate Professor of Cardiovascular Medicine, University of Oxford
Honorary Consultant Cardiologist, Oxford University Hospitals NHS Trust
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Mitral regurgitation, the most common heart valve disorder in high-income countries, has until now been considered a degenerative disorder, which results from damage over time due to ‘wear and tear’. As a result, the focus of medical practitioners has been on treating the disorder – by repairing or replacing the valve – rather than preventing it. This is partly because there has been a lack of large-scale, longitudinal studies investigating the effect of risk factors on the condition.
We set out to analyse data on 5.5 million patients in the UK over 10 years. Our findings show, for the first time, that elevated blood pressure is an important risk factor for mitral regurgitation. Consistent with prior evidence on blood pressure associations with other cardiovascular disease – such as stroke and heart attacks – we found an association with mitral regurgitation that is continuous across the whole spectrum of blood pressure. More specifically, every 20 mmHg higher baseline systolic blood pressure is associated with a 26% increased risk of mitral regurgitation, with no threshold below or above which this relationship is not true.
The association we found was only partially mediated by conditions that are established causes of secondary mitral regurgitation, which suggests that high blood pressure has a direct and independent effect on valve degeneration.
MedicalResearch.com: What should readers take away from your report?
Response: The main take-away for readers should be that our research suggests mitral regurgitation, a common and disabling valve disorder, is not an inevitable consequence of ageing as previously assumed, but may be preventable.
This condition leads to a backflow of blood into the heart and makes it less efficient at pumping blood around the body. The disorder can cause symptoms such as shortness of breath, tiredness, dizziness and palpitations. In severe cases it can lead to heart failure, and may be associated with a greater risk of mortality.
Given the large and growing burden of mitral valve disease, particularly among older people, we believe these findings are likely to have significant implications for medical policy and practice around the world.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Effective and affordable preventative measures are needed to tackle the growing burden of mitral valve disease. Future research should establish the causality of the association we found between high blood pressure and mitral regurgitation, and test whether lowering blood pressure – for example, through exercise, diet or blood pressure-lowering drugs – could reduce the risk of the disorder occurring.
Disclosures: I receive a stipend as a specialty consulting editor for PLOS Medicine and serve on the journal’s editorial board.
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These findings were published in PLOS Medicine: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002404
Rahimi K, Mohseni H, Otto CM, Conrad N, Tran J, Nazarzadeh M, et al. (2017) Elevated blood pressure and risk of mitral regurgitation: A longitudinal cohort study of 5.5 million United Kingdom adults. PLoS Med14(10): e1002404. https://doi.org/10.1371/journal.pmed.1002404
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