The J-curve of cardiovascular disease risk and how it relates to isolated systolic hypertension

Abstract

Controversy persists regarding the presence and significance of the “J-curves” of increased cardiovascular disease (CVD) risk as they relate to older people with isolated systolic hypertension (ISH). A recent Framingham primary outcome study showed that of the 4 blood pressure (BP) components [diastolic BP (DBP), systolic BP (SBP), pulse pressure (PP), and mean arterial pressure (MAP)] only DBP showed non-linear tendencies, which presented as a J-curve of increased CVD risk. The reduction in DBP was associated with an increase in PP, the latter of which serves as a marker of increased arterial stiffness. On the other hand, when primary CVD events result in poor cardiac function, the presence of combined SBP and DBP J-curves serve as predictors of secondary CVD events—so called “reverse causality”; thus, risk is associated with decreased rather than by increased SBP. Lastly, treatment-induced cardiac risk is a potential third explanation for J-curves that occur in the presence of hemodynamically significant coronary artery stenosis. This review is directed at a better understanding of causes and consequences of the J-curve phenomena.