Back to square one: what is a normal blood pressure and for whom?
Published Jun 21, 2018 · T. Lüscher
European heart journal
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Abstract
High blood pressure was one of the first recognized risk factors, but the level at which hypertension can be diagnosed varied hugely over time. Indeed, in the old days it was 100 mmHg plus age in the systolic range, then the experts settled at 160/95 mmHg just to set it at 140/90 mmHg a few years later. Now, the US Guidelines have defined truly normal blood pressure at levels below 120 mmHg systolic. If any of the readers are confused at a higher level they are ready to read The Editors Page ‘What is a normal blood pressure?’ There they will learn that our ancestors had blood pressures in the range of 110/70 mmHg or lower throughout their life, if they survived war, hunger, and infections. The rather emotional transatlantic debate about the new US recommendations must thus be interpreted in a wider context. We must rethink target values in a personalized fashion and consider global and life time risk when deciding treatment strategies for an individual patient. This view is challenged by Franz Messerli from the Inselspital University Hospital Bern in Switzerland in his Viewpoint ‘Changing definition of hypertension in guidelines: how innocent a number game?’ He is concerned about the fact that as of November 2017, with the publication of the new US Guidelines on Hypertension, there would now be millions more hypertensives at age 60 and above in the USA alone, and he expresses his hope that despite those recommendations, physicians will continue to treat them and not mm of Hg only. Things are even more complicated than that. Indeed, not only blood pressure as such, but blood pressure variability is associated with increased cardiovascular risk. In their article entitled ‘Blood pressure variability and risk of cardiovascular events and death in patients with hypertension and different baseline risks’, Eivind Berge and colleagues from the Oslo University Hospital in Norway evaluated this in the VALUE trial enrolling 13 803 patients of which 11.3% had a cardiovascular event. Patients in the highest quintile of standard deviation of blood pressure had a 2.1-fold increased cardiovascular risk. A 5 mmHg increase in standard deviation of systolic blood pressure was associated with a 10% increase in the risk of death. The effects were stronger in younger patients and in those with lower systolic blood pressure. Thus, higher visit-to-visit systolic blood pressure variability is associated with increased risk of events, irrespective of baseline risk, particularly in younger patients and those with lower systolic blood pressure. These novel findings are further discussed in an Editorial by Stephane Laurent from the Hôpital Européen Georges Pompidou in Paris. As in the hypertensive population at large, optimal blood pressure remains uncertain in patients with type 2 diabetes mellitus, especially as they have been excluded in the landmark SPRINT trial. Also, there is concern for increased risk with low diastolic blood pressure. In their article entitled ‘Blood pressure and cardiovascular outcomes in patients with diabetes and high cardiovascular risk’, Brian Allan Bergmark and the SAVOR-TIMI 53 Investigators analysed the association between blood pressure and cardiovascular outcomes in 12 175 high-risk patients with type 2 diabetes mellitus. Adjusted risk of the composite endpoint of cardiovascular death, myocardial infarction, or ischaemic stroke showed U-shaped relationships with baseline systolic blood pressure and diastolic blood pressure, with nadirs at systolic blood pressure 130–140 mmHg or diastolic blood pressure 80–90 mmHg (Figure 1). Diastolic blood pressure below 60 mmHg was associated with a 2.3-fold increased risk of myocardial infarction. Thus, in patients with diabetes and elevated cardiovascular risk, even after extensive adjustment for underlying disease burden, there was a persistent association of low diastolic blood pressure with subclinical myocardial injury and risk of myocardial infarction. The obesity epidemic is a big threat for the Western world, and increasingly so also in developing countries. Indeed, more and more children are obese, putting them at an enormous life time risk. In their article ‘Distinct child-to-adult body mass index trajectories are associated with different levels of adult cardiometabolic risk’, Marie-Jeanne Buscot and colleagues from the University of Tasmania Menzies Institute for Medical Research in Hobart in Australia investigated body mass index trajectories from