By Bianca Nogrady
People with peripheral artery disease (PAD) may be vulnerable to cardiovascular events if their blood pressure is lowered too much, a new Australian study has found.
Writing in the Journal of the American Heart Association, researchers reported the results of an observational cohort study in 2773 people with PAD.
Over a median follow up of 1.7 years, they saw that patients with a systolic blood pressure (SBP) at or below 120 mmHg had a significant 36% greater odds of a major cardiovascular event (myocardial infarction, stroke or cardiovascular death) compared with those with a SBP between 121 and 140 mmHg.
Participants with a SBP greater than 140 mmHg had a 23% higher risk of a major cardiovascular event, although this was only borderline significant.
The biggest impact was seen on myocardial infarction risk in the 2030 patients treated with antihypertensives. Those with a SBP at or below 120 mmHg had a significant 51% higher odds of myocardial infarction, while those with SBP above 140 mmHg had a 44% higher odds compared with individuals with a SBP between 121 and 140 mmHg.
In contrast, the researchers did not see an increased risk of stroke alone in either the SBP at or below 120 mmHg or the more than 140 mmHg group, but there was a significant increase in cardiovascular mortality in those with SBP at or under 120 mmHg.
Study coauthor and vascular surgeon Dr Bernard Bourke, from Gosford Vascular Services, said there had long been a concern among geriatricians about the risk of overtreating hypertension in patients with PAD, particularly older patients.
‘Some of those patients, because they get stiffer arteries as they get older, they actually need a higher blood pressure than a 30-year-old,’ said Dr Bourke, immediate past President of the Australian and New Zealand Society for Vascular Disease.
‘While blood pressure control is important in preventing the development of coronary disease or carotid artery disease or aneurysms, when they’ve actually got the disease they may, in certain situations, need a higher blood pressure.’
Dr Bourke told Cardiology Today that lower was not necessarily better, and that doctors should rethink lowering BP in these patients beyond 120 mmHg.
‘What the paper shows is that we are probably just scratching the surface in terms of identifying different blood pressure targets for different groups to find that benefit.’
JAHA 2019; 8: e010748; doi: 10.1161/JAHA.118.010748.