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Understanding Pulse pressure in clinical settings. Info from web.
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  Ref: Mayo Clinic, others Pulse pressure: Blood pressure readings are given in two numbers. The top number is themaimum pressure your heart eerts while beating !systolic pressure , and the bottom number isthe amount of pressure in your arteries between beats !diastolic pressure . The numeric difference between your systolic and diastolic blood pressure is called your pulse pressure. #or eample, if your resting blood pressure is $%&'(& millimeters of mercury !mm )g , your pulse pressure is *& + which is considered a normal and healthy pulse pressure. high pulse pressure may be a strong predictor of heart problems and, especially for older adults,if your pulse pressure is greater than -& it is considered a ris factor for cardiovascular disease./enerally, a pulse pressure greater than *& mm )g is abnormal.  pulse pressure lower than *&may mean you have poor heart function, while a higher pulse pressure may mean your heart0svalves are leay !valve regurgitation .The most important cause of elevated pulse pressure is stiffness of the aorta, the largest artery inthe body. The stiffness may be due to high blood pressure or fatty deposits on the walls of thearteries !atherosclerosis . The greater your pulse pressure, the stiffer and more damaged thevessels are thought to be. 1ther conditions + including severe iron deficiency !anemia andoveractive thyroid !hyperthyroidism + can increase pulse pressure as well.Treating high blood pressure usually reduces pulse pressure.The ris of coronary event associated with a PP of 2& or more was actually significantly higher than that associated with hypertension. Thus, PP may be a stronger predictor of ris than ishypertension.3t also appears to be an independent ris factor. 3n other words it addsris to the other factors./enerally, this phenomenon was not seen at less than 4& years of age, visible at 4&546, andstrongest after -&.3n these three age groups: diastolic is more predictive in less than 4&. t 4&546 systolic is most predictive and after -& the pulse pressure is most important. s one ages there is a gradual shift inthe strength of prediction of ris from diastolic to systolic to PP.Results of several longitudinal studies in older patients with hypertension indicate that a high PP isa sensitive marer for carotid artery stenosis !narrowing , which increases the ris of stroe,coronary heart disease, and sudden death.7hile the mean arterial pressure should be about the same in all regions, notice how the pulse pressure changes. #or eample, compare the two arteries used for the anle'brachial inde. The posterior tibial artery in the anle is smaller with a lower compliance. Therefore, you epect ahigher pulse pressure.  higher pulse pressure implies a higher systolic pressure, assuming themean arterial pressure is about the same. This is one reason why the normal anle'brachial inde is$.$ to $.8. !nother reason is that the posterior tibial artery is 9ust before where the artery branchesinto many small vessels in the foot. s discussed below, this causes a reflected wave, which in the posterior tibial artery adds to the systolic pressure.   Consider a patient with claudication due to a constriction in the femoral artery as a result of atherosclerosis. #low through this region is reduced, and distal to the contriction the mean arterial pressure and other pressures are reduced. This would give an anle'brachial inde below &.6,which is abnormal. nd it is not uncommon in patients where atherosclerosis develops in the legarteries for the inde to be much lower than &.6.ffect of Branching of rteries#inally, let0s go a further step and loo at how adding branching to the arterial system affects the pulse pressure. 7hen a discontinuity is added to an elastic system, a propagating wave tends tohave a reflection. The branching of the aorta into the common iliac arteries is an especiallyimportant place for this.3n a healthy, young aorta the reflection tends to arrive during diastole, which increases thediastolic pressure somewhat. The reflected wave increases the diastolic pressure. ;ow consider a stiffer, less compliant aorta, This would be typical in an older person. Both wavestravel faster in this stiffer system. 1bserve that the initial wave creates a somewhat higher pulse pressure because the artery is stiffer. ;et, note that the reflected wave occurs earlier, since ittravels faster. Thus, now it mainly occurs during systole and not diastole. ;ow observe theaddition of the initial wave and the reflected wave. The reflected wave here increases the systolic pressure, but not the diastolic pressure, as in the more compliant artery shown to the left. ;ow, theaddition of the initial wave and the reflected wave gives a higher systolic pressure and a lower diastolic pressure. This situation is why older people tend to develop a higher pulse pressure. 3ngeneral, both a higher pulse pressure and a high mean arterial pressure are ris factors for cardiovascular disease.1ne disadvantage of the lower diastolic pressure during aging is that it affects coronary bloodflow. The small coronary vessels are s<uee=ed shut during systole, so that coronary blood flowoccurs only during diastole. Thus coronary blood flow is driven by the diastolic pressure. 3f this islower, there is a reduction in the supply of oygen to the heart and thus a reduced maimumeercise level. This is not a huge issue, but is one reason the maimum eercise tolerance on theaverage tends to decrease with age.
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