medwireNews: Analysis of the SEAS study participants pinpoints the blood pressure (BP) range that physicians should target for best outcomes in patients with asymptomatic aortic stenosis (AS).
Over 4 years of the SEAS study, the risk of most outcomes was lowest among patients with “[n]ormal to mildly elevated BP,” report Olav Nielsen (Copenhagen University Hospital of Bispebjerg, Denmark) and colleagues in Circulation.
SEAS originally reported no effect of lipid-lowering medication in its 1873 patients with asymptomatic mild-to-moderate AS. But editorialist Patrick O’Gara (Brigham and Women’s Hospital, Boston, Massachusetts, USA) says: “Although historically viewed as a ‘negative’ trial, the SEAS study has proven a robust source of information on the natural history and assessment of AS.”
The latest findings “now provide the clinician with reasonable blood pressure boundaries within which to manage this challenging group of patients”, he says.
Mortality, heart failure, cardiovascular death, myocardial infarction and aortic valve replacement were all least frequent among patients in the middle two quartiles of systolic and diastolic BP during follow-up: 120–195 and 70–89 mmHg, respectively.
O’Gara says that these U-shaped patterns “are consistent with the notion that critical reductions in coronary perfusion pressure can have deleterious consequences in vulnerable patients with pre-existing large or small vessel [coronary artery disease], abnormal coronary flow reserve, and altered myocardial properties.”
The one exception was stroke, which occurred less frequently among patients with BP below these ranges.
Diastolic BP over 90 mmHg remained significantly associated with all outcomes after accounting for gender, age, history of hypertension, left ventricular hypertrophy and AS severity, while diastolic BP below 70 mmHg was associated with heart failure. In addition, systolic BP below 120 mmHg was associated with myocardial infarction and all-cause and cardiovascular mortality.
The researchers refined the systolic BP estimate further by looking at average BP over time, finding that patient survival was best when systolic BP was between 130 and 139 mmHg, as long as diastolic BP was between 60 and 90 mmHg.
They stress that randomised trials are needed to properly define optimal BP management, but say: “Until such studies emerge, our observational study indicates that, in asymptomatic AS, target diastolic BP should be 80 mmHg, while at the same time aiming for a systolic BP from 130 to 139 mmHg.
“We advocate that patients with BP lower than 120 mmHg systolic or 70 mmHg diastolic are carefully examined for reversible conditions that could lead to a low BP and worse prognosis.”
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