Tuesday, November 27, 2007

Pulse pressure

If you're a little stiff from aging--in an arterial sense--new data from the Baltimore Longitudinal Aging Study suggests that you are at increased risk of memory troubles.

Here's one more vital sign to add to your life list: pulse pressure. This is the difference between the top and bottom numbers of your blood pressure. The top number or systolic blood pressure is that pressure generated by your heart as it squeezes blood from the left ventricle into the aorta and from there to the rest of your body. The diastolic pressure on the bottom represents the residual pressure in your vascular system as the heart relaxes and refills with blood in preparation for the next beat. Whether the top or the bottom value is more relevant to your health and length of life has been a matter of some debate through the years, but the systolic one is now generally accepted as most important. That said, not only is diastolic hypertension also of interest, but the gap between systolic pressure is increasingly noted as relevant to future stroke risk.

So, ideal blood pressure is less than or equal to 115/75. The difference, 115-75 or 40, is the pulse pressure. As people age and get all sorts of fat-laden schmutz in the walls of their arteries, this difference widens. Interestingly, while 170/110 (pulse pressure 60) would make your doctor pale, 170/70 (pulse pressure 100) is even worse yet.

Maryland docs studying Maryland old folks as part of the Baltimore Longitudinal Aging Study looked for a correlation between memories lost and pulse pressure. Sure enough, increasing pulse pressures and higher pulse wave velocity* were directly correlated with decreasing memory and concentration functions in aging individuals.

No more of those "at least your bottom number's okay" sort of reassurances of yore. The current goal is to keep the arteries pliable from the get-go by jumping all over cardiovascular risk factors such as blood pressure and cholesterol values. Those strategies that keep the arteries elastic--such as exercise and eating oatmeal--and those meds that directly promote endothelial cell health (those are the little hummers that line your blood vessels) such as ACE inhibitors are top of our A-list.

*The mountainous curve which can be traced graphically from the pulse in your wrist as a wave of pressure goes by with each beat of the heart; the steeper the mountain, the bigger the difference between systolic and diastolic.


Ruth said...

Interesting! I have never heard of this before and will have to share it with our team...and check a few BPs.

kenju said...

When me husband finally consented to let me take him to the hospital after his recent stroke, his pressure was 245 over 127.The ER doc said he had never seen someone (alive) with pressure that high before.

Femail doc said...

Ruth, I'm delighted that your part of the medical care team would get involved in BP checks. Do you see a lot of stroke patients?

Kenju, what scary high blood pressure in an otherwise scary experience. I hope your husband is making a good recovery. I will be speaking about blood pressure control to some post stroke patients early next year--any tips about what you and your husband wish you'd known before his stroke or now as he recovers?