Diastolic blood pressure, aortic atheroma, and prognosis in hypertension: New insights into a complex association

Abstract

ObjectivesOur study aimed at determining the interaction between the prognostic value of diastolic blood pressure (DBP) and aortic atherosclerosis (ATS). BackgroundWith aging, equal systolic blood pressures (SBPs) become associated with low DBPs; i.e., high pulse pressures (PPs) become associated with a high risk of cardiovascular death. This association is usually ascribed to aortic stiffening with age but the precise impact of low DBP per se is yet uncertain. Methods938 hypertensive patients recruited in the seventies had an aortic ATS score at pretreatment aortography. All-cause and cardiovascular deaths were assessed 20 years later. The prognostic values of DBP and SBP were assessed by a multivariate Cox regression model and their interactions with ATS examined. ResultsIn the presence of ATS, an increase of 10 mmHg in DBP was associated with a protective effect: hazard ratios 0.84 [0.72–0.99] for cardiovascular death and 0.88 [0.78–1.00] for all-cause death. However, in the absence of ATS, DBP had no prognostic value: hazard ratios 1.05 [0.89–1.23] for cardiovascular death and 0.99 [0.88–1.11] for all-cause death (p for interaction: 0.061 and 0.087, respectively). No interaction was found between SBP and ATS (p for interaction > 0.40). ConclusionsThe prognostic values of DBP and aortic atheroma are not superimposable; yet, they are tightly connected: a low DBP is disadvantageous only in the presence of a pathologic aorta. Aortic atherosclerosis may explain, at least partly, in some high risk populations, the J-shape of the already reported DBP-outcome relationship.