Importance of pulse pressure at low systolic blood pressure

This commentary refers to ‘On cerebrotoxicity of antihypertensive therapy and risk factor cosmetics’, by F.H. Messerli et al., https://doi.org/10.1093/eurheartj/ehaa971 and the discussion piece ‘How to identify which patients should not have a systolic blood pressure target of <120 mmHg’, by J. D. Spence et al., https://doi.org/10.1093/eurheartj/ehab552.

Drs. Spence et al. rise an important point regarding diastolic BP.¹ In their unwavering resolve to lower systolic BP to values below 120 mmHg, many clinicians tend to overlook the dire consequences of too low a diastolic BP in some patients. Not only does a diastolic BP below 60 mmHg increase the risk of type 2 MI since coronary is exclusively perfused during diastole² but as Spence et al. point out, it also compromises the cerebral circulation.¹ Could it be possible that some of the ‘cerebrotoxic effects’ observed with antihypertensive therapy in the UK Biobank Cohort Study of Wartolowska and Webb were actually resulting from an inappropriately low perfusion pressure in the cerebral cortex secondary to too low a diastolic BP? If so, their principal conclusion that lowering diastolic BP to below 70 mmHg in patients younger than 50 will lower WMH burden would become questionable.

The Lancet recently lamented that the NICE Hypertension Guidelines made a ‘pragmatic compromise’ by keeping the definition of hypertension at 140/90 mmHg or greater and instead advised that ‘Updating so that all patients with an SBP above the 120 mmHg ideal and a cardiovascular risk score of 10% or higher would be offered treatment would have shown true grit’.³ In contrast, we arbitrarily suggested that optimal SBP levels for most adult patients should be about 100 plus 1/2 the age.⁴ This would correspond to an SBP of 120 mmHg for patients aged 40 years, 130 mmHg for patients aged 60 years, and 140 mmHg for patients aged 80 years.⁴ Bringing everybody’s systolic BP to 120 mmHg or below may be true grit for The Lancet but as Spence et al. emphasize perhaps less so for patients with an increased pulse pressure. We respectfully dared to consider this 120 m mmHg proposal absurd rather than true grit and hope that physicians still will continue to treat patients rather than mmHg only.⁵ However, we wholeheartedly agree with Spence et al. that a pulse pressure above 60 mmHg should preclude lowering systolic BP to 120 mmHg or below particularly in older patients.

Conflict of interest: none declared.

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