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Higher SBPs linked to lower mortality in CHF

Monday, December 08, 2008

Heart 2008; 95: 56-62

MedWire News: Meta-analysis findings demonstrate an inverse relationship between systolic blood pressure (SBP) levels and mortality in patients with chronic heart failure (CHF).

The study’s authors say the apparent paradoxical benefit of higher SBP levels in this population could have an application in optimizing cardiac resynchronization therapy.

Claire Raphael (Imperial College London, UK) and colleagues conducted a meta-analysis of studies in CHF patients with sufficient data to calculate mortality hazard ratios for changes in SBP, and in which SBP was measured at baseline.

They report in the journal Heart that a higher SBP was associated with a better prognosis in all 10 trials meeting their inclusion criteria.

Dividing patients according to 10-mmHg SBP increments revealed that the degree of benefit varied across trials. Overall, each 10-mmHg increase in SBP was associated with a 13% decrease in mortality, while in those studies with SBPs falling in the lowest tertile (mean 109 mmHg) mortality fell by 18% with each 10-mmHg increment.

Raphael and co-authors report that the relationship was unaffected by dose or type of medication, or ischemic or nonischemic etiology, and was not due to heterogeneity between studies.

The authors contrast their findings with those from numerous meta-analyses in patients without HF, in whom a higher SBP is associated with poorer prognosis.

“A close relationship between SBP and mortality in CHF might be expected from consideration of cardiac physiology,” write Raphael and team, however.

They explain that mean arterial BP reflects the ejection fraction and cardiac output; thus CHF patients with higher BP levels have better cardiac function than those with lower BP levels, and therefore a more favorable prognosis.

Commenting on the study, Vinay Thohan and William Little, of Wake University School of Medicine in Winston-Salem, North Carolina, USA, recommend monitoring frequent patient-acquired home BPs when caring for patients with CHF.

“A BP target of 110/70 mmHg is a reasonable goal until we have additional information from additional observations or formal clinical trials,” they write in a related editorial.