A study published ahead-of-print in the Journal of the American College of Cardiology suggests that higher blood pressure levels in very old patients do not predict mortality or major cardiovascular events but low pulse pressure amplification (the ratio of brachial/carotid pulse pressure, which calculates the percentage of increase of pulse pressure from the central to the peripheral arteries) in this population does predict such events.
Athanase Benetos, Department of Geriatrics, University Hospital of Nancy, Vandoeuvre les Nancy, France, and others wrote that the association between blood pressure and mortality and morbidity in frail, very elderly patients (those aged over 80 years) living in nursing homes is controversial as they report that there are “several studies showing a lack of such a relationship or even an inverse relationship.” Thus, they commented, it is “logical to seek alternative approaches” to estimating cardiovascular risk in the very elderly population. The aim of the PARTAGE (Predictive values of blood pressure and arterial stiffness in institutionalised very aged population) study was to evaluation the prognostic values of arterial mechanical parameters such as pulse pressure amplification and pulse wave velocity (the speed of the transmission of the pressure waves), as well as blood pressure on total mortality and cardiovascular events in the very elderly individuals living in nursing homes.
Of the 1,126 patients enrolled in the study, the mean age was 88±5 years, the majority (78%) were women, and 839 completed the two-year follow-up (of those who did not complete the follow-up, 247 died and 40 were lost to follow-up). Benetos et al found that a lower pulse pressure amplification (the non increase in pulse pressure towards the peripheral arteries is a sign of excessive arterial ageing and arterial stiffness) was associated with both higher total mortality (p=0.003) and more major cardiovascular events (p=0.004). They reported: “The higher the pulse pressure amplification was, the lower the total mortality and major cardiovascular events. In this multivariate model, a 10% increase in pulse pressure amplification was associated with a significant 24% decrease in total mortality and 17% decrease in major cardiovascular events.”
However, pulse wave velocity, another marker of arterial stiffness, was not associated with major cardiovascular events or total mortality.
Paradoxically, a 10mmHg increase in systolic blood pressure, diastolic blood pressure, or mean arterial pressure was associated with a significant decrease in the risk of total mortality (by 9%, 16%, and 15%, respectively). However, no relationship between blood pressure levels and major cardiovascular events were observed. Benetos et al explained that, in very elderly frail individuals, “low systolic blood pressure may not be simply a sign of so-called good arterial health but often of malnutrition and comorbidities, such as heart failure, neurological disorders, and other comorbidities associated with poor prognosis.”
According to the authors, irrespective of why there appears to be an inverse relationship between blood pressure levels and mortality in this population, their results “indicate that high blood pressure levels in very elderly frail individuals are evidently not very reliable in order to select subjects at high risk and define those that will be treated, whereas pulse pressure amplification provides more pertinent information about the patient’s prognosis.” Benetos told Cardiovascular News that the “superiority” of pulse pressure amplification is explained by the fact that the ratio brachial/carotid pulse pressure is independent of the absolute blood pressure levels, which are dependent on comorbidities.
The authors reported that their study raised the issue of the use of blood pressure levels as an indicator of protection in a frail, very elderly population. Benetos explained: “We may have to reconsider the clinical criteria for treating old frail people for hypertension. This is of major interest because in this polymedicated subjects (more than seven different drugs per day per person in the PARTAGE study) iatrogenic-induced problems are also a major issue.”