Low BP may flag cardiac risk in diabetes patients
medwireNews: Analysis of the SAVOR-TIMI trial supports a relationship between low blood pressure (BP) and cardiovascular (CV) risk in patients with type 2 diabetes.
In line with studies of patients without diabetes, the results show a U-shaped relationship between baseline systolic (S)BP and major adverse cardiovascular events (MACE) and CV death, as well as hospitalization for heart failure.
For example, the lowest risk for MACE was observed at SBPs of around 130 to 140 mmHg. The risk was elevated by around 20% among patients whose SBP was 110 mmHg or below or greater than 150 mmHg, relative to patients in the reference SBP category of greater than 120 mmHg to 130 mmHg.
Diastolic (D)BP also had a U-shaped association with MACE, and with myocardial infarction (MI), the researchers report in the European Heart Journal.
For this analysis, Deepak Bhatt (Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA) and study co-authors excluded patients with pre-existing heart failure, which could account for the increased CV risk at low BP. This left 12,175 patients, who between them had 407 CV deaths, 426 MIs, and 224 ischemic strokes during the 2.1 years of follow-up.
The team found clear linear relationships between BP and ischemic stroke, which they say “provides assurance that low blood pressure was not simply a marker of overall frailty in this population.”
The associations were independent of multiple variables including medical history, diabetes duration, glycated hemoglobin levels, receipt of saxagliptin versus placebo, and the cardiac biomarkers N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin-T (hsTnT).
SBP and DBP also had U-shaped relationships with patients’ odds for having hsTNT levels of 14 ng/L or higher, as a marker of subclinical cardiac damage.
Bhatt and team highlight the association of DBP with both clinical (MI) and subclinical (hsTNT) myocardial damage, saying that there is a “compelling physiologic explanation” for this relationship, which has “potential clinical importance.”
They explain: “Coronary filling is dependent on central aortic pressure, largely during diastole, and this observation may support concern for low DBP as a cause of insufficient coronary perfusion, subclinical myocardial injury, and MI.”
However, they stress that although their observational data offer support for such a causative effect, they do not prove it.
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