Pulse pressure
Encyclopedia
Pulse Pressure is most easily defined as being the amount of pressure required to create the feeling of a pulse. Measured in millimeters of mercury (mmHg), the pressure difference between the systolic and diastolic pressures give you the amount of pressure change to create the pulse, which is the pulse pressure. If your resting blood pressure is (systolic/diastolic) 120/80 millimeters of mercury (mmHg), your pulse pressure is 40 — which is considered a normal and healthy pulse pressure.
Theoretically, the systemic pulse pressure can be conceptualized as being proportional to stroke volume
, or the amount of blood ejected from the left ventricle during systole and inversely proportional to the compliance of the aorta.
The aorta
has the highest compliance in the arterial system due in part to a relatively greater proportion of elastin fibers versus smooth muscle and collagen. This serves the important function of dampening the pulsatile output of the left ventricle, thereby reducing the pulse pressure. If the aorta becomes rigid in conditions such as arteriosclerosis
or atherosclerosis
, the pulse pressure would be very high.
In trauma a low or narrow pulse pressure suggests significant blood loss (insufficient preload leading to reduced cardiac output).
If the pulse pressure is extremely low, i.e. 25 mmHg or less, the cause may be low stroke volume, as in Congestive Heart Failure
and/or shock.
A narrow pulse pressure is also caused by aortic stenosis and cardiac tamponade
.
pressure in healthy adults, sitting position, is about 40 mmHg. The pulse pressure increases with exercise due to increased stroke volume, healthy values being up to pulse pressures of about 100 mmHg, simultaneously as total peripheral resistance
drops during exercise. In healthy individuals the pulse pressure will typically return to normal within about 10 minutes. For most individuals, during aerobic exercise, the systolic
pressure progressively increases while the diastolic remains about the same. In some very aerobically athletic individuals, for example distance runners, the diastolic will progressively fall as the systolic
increases. This behavior facilitates a much greater increase in stroke volume
and cardiac output
at a lower mean arterial pressure
and enables much greater aerobic capacity and physical performance. The diastolic drop reflects a much greater fall in total peripheral resistance of the muscle arteriole
s in response to the exercise (a greater proportion of red versus white muscle tissue). Individuals with larger BMIs due to increased muscle mass (body builders) have also been shown to have lower diastolic pressures and larger pulse pressures.
), arteriovenous malformation
(an extra path for blood to travel from a high pressure artery to a low pressure vein without the gradient of a capillary bed), hyperthyroidism
or some combination. (A chronically increased stroke volume is also a technical possibility, but very rare in practice.) While some drugs for hypertension have the side effect of increasing resting pulse pressure irreversibly, other hypertension drugs, such as ACE Inhibitors
, have been shown to lower pulse pressure. A high resting pulse pressure is harmful and tends to accelerate the normal aging of body organs, particularly the heart, the brain and kidneys. A high pulse pressure combined with bradycardia
and an irregular breathing pattern is associated with increased intracranial pressure
and should be reported to a physician immediately. This is known as the Cushing reflex
and can be seen in patients after head trauma related to intracranial hemorrhage or edema.
Examples: (these are examples of WIDENING pulse pressure causes)
. The authors of the meta-analysis suggest that this helps to explain the apparent increase in risk sometimes associated with low diastolic pressure, and warn that some medications for high blood pressure may actually increase the pulse pressure and the risk of heart disease.
).
Calculation
Formally it is the systolic pressure minus the diastolic pressure.Theoretically, the systemic pulse pressure can be conceptualized as being proportional to stroke volume
Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. SV is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume...
, or the amount of blood ejected from the left ventricle during systole and inversely proportional to the compliance of the aorta.
The aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
has the highest compliance in the arterial system due in part to a relatively greater proportion of elastin fibers versus smooth muscle and collagen. This serves the important function of dampening the pulsatile output of the left ventricle, thereby reducing the pulse pressure. If the aorta becomes rigid in conditions such as arteriosclerosis
Arteriosclerosis
Arteriosclerosis refers to a stiffening of arteries.Arteriosclerosis is a general term describing any hardening of medium or large arteries It should not be confused with "arteriolosclerosis" or "atherosclerosis".Also known by the name "myoconditis" which is...
or atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
, the pulse pressure would be very high.
- Systemic pulse pressure = Psystolic - Pdiastolic = 120mmHg - 80mmHg = 40mmHg
- Pulmonary pulse pressure = Psystolic - Pdiastolic = 25mmHg - 10mmHg = 15mmHg
Low (Narrow) Pulse Pressure
A pulse pressure is considered abnormally low if it is less than 25% of the systolic value. The most common cause of a low (narrow) pulse pressure is a drop in left ventricular stroke volume.In trauma a low or narrow pulse pressure suggests significant blood loss (insufficient preload leading to reduced cardiac output).
If the pulse pressure is extremely low, i.e. 25 mmHg or less, the cause may be low stroke volume, as in Congestive Heart Failure
Congestive heart failure
Heart failure often called congestive heart failure is generally defined as the inability of the heart to supply sufficient blood flow to meet the needs of the body. Heart failure can cause a number of symptoms including shortness of breath, leg swelling, and exercise intolerance. The condition...
and/or shock.
A narrow pulse pressure is also caused by aortic stenosis and cardiac tamponade
Cardiac tamponade
Cardiac tamponade, also known as pericardial tamponade, is an emergency condition in which fluid accumulates in the pericardium ....
.
High values during or shortly after exercise
Usually, the resting pulsePulse
In medicine, one's pulse represents the tactile arterial palpation of the heartbeat by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed against a bone, such as at the neck , at the wrist , behind the knee , on the inside of the elbow , and near the...
pressure in healthy adults, sitting position, is about 40 mmHg. The pulse pressure increases with exercise due to increased stroke volume, healthy values being up to pulse pressures of about 100 mmHg, simultaneously as total peripheral resistance
Total peripheral resistance
Vasculature throughout the entire body can be thought of as two separate circuits - one is the systemic circulation, while the other is the pulmonary circulation. Total peripheral resistance is the sum of the resistance of all peripheral vasculature in the systemic circulation...
drops during exercise. In healthy individuals the pulse pressure will typically return to normal within about 10 minutes. For most individuals, during aerobic exercise, the systolic
Systole (medicine)
Systole is the contraction of the heart. Used alone, it usually means the contraction of the left ventricle.In all mammals, the heart has 4 chambers. The left and right ventricles pump together. The atria and ventricles pump in sequence...
pressure progressively increases while the diastolic remains about the same. In some very aerobically athletic individuals, for example distance runners, the diastolic will progressively fall as the systolic
Systole (medicine)
Systole is the contraction of the heart. Used alone, it usually means the contraction of the left ventricle.In all mammals, the heart has 4 chambers. The left and right ventricles pump together. The atria and ventricles pump in sequence...
increases. This behavior facilitates a much greater increase in stroke volume
Stroke volume
In cardiovascular physiology, stroke volume is the volume of blood pumped from one ventricle of the heart with each beat. SV is calculated using measurements of ventricle volumes from an echocardiogram and subtracting the volume of the blood in the ventricle at the end of a beat from the volume...
and cardiac output
Cardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
at a lower mean arterial pressure
Mean arterial pressure
The mean arterial pressure is a term used in medicine to describe an average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.-Calculation:...
and enables much greater aerobic capacity and physical performance. The diastolic drop reflects a much greater fall in total peripheral resistance of the muscle arteriole
Arteriole
An arteriole is a small diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries.Arterioles have muscular walls and are the primary site of vascular resistance...
s in response to the exercise (a greater proportion of red versus white muscle tissue). Individuals with larger BMIs due to increased muscle mass (body builders) have also been shown to have lower diastolic pressures and larger pulse pressures.
Consistently high values
If the usual resting pulse pressure is consistently greater than 40 mmHg, e.g. 60 or 80 mmHg, the most likely basis is stiffness of the major arteries, aortic regurgitation (a leak in the aortic valveAortic valve
The aortic valve is one of the valves of the heart. It is normally tricuspid , although in 1% of the population it is found to be congenitally bicuspid . It lies between the left ventricle and the aorta....
), arteriovenous malformation
Arteriovenous malformation
Arteriovenous malformation or AVM is an abnormal connection between veins and arteries, usually congenital. This pathology is widely known because of its occurrence in the central nervous system, but can appear in any location. An arteriovenous malformation is a vascular anomaly. It is a...
(an extra path for blood to travel from a high pressure artery to a low pressure vein without the gradient of a capillary bed), hyperthyroidism
Hyperthyroidism
Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
or some combination. (A chronically increased stroke volume is also a technical possibility, but very rare in practice.) While some drugs for hypertension have the side effect of increasing resting pulse pressure irreversibly, other hypertension drugs, such as ACE Inhibitors
ACE inhibitor
ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...
, have been shown to lower pulse pressure. A high resting pulse pressure is harmful and tends to accelerate the normal aging of body organs, particularly the heart, the brain and kidneys. A high pulse pressure combined with bradycardia
Bradycardia
Bradycardia , in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their heart...
and an irregular breathing pattern is associated with increased intracranial pressure
Intracranial pressure
Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...
and should be reported to a physician immediately. This is known as the Cushing reflex
Cushing reflex
Cushing reflex is a physiological nervous system response to increased intracranial pressure that results in Cushing's triad of widening pulse pressure, irregular breathing, and a reduction of the...
and can be seen in patients after head trauma related to intracranial hemorrhage or edema.
Examples: (these are examples of WIDENING pulse pressure causes)
- AtherosclerosisAtherosclerosisAtherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
- Arteriovenous fistulaArteriovenous fistulaAn arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm....
- Chronic aortic regurgitation
- Thyrotoxicosis
- FeverFeverFever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
- Anaemia
- PregnancyPregnancyPregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
- AnxietyAnxietyAnxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
- Heart blockHeart blockA heart block can be a blockage at any level of the electrical conduction system of the heart .* Blocks that occur within the sinoatrial node are described as SA nodal blocks....
- Aortic dissectionAortic dissectionAortic dissection occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta and force the layers apart. The dissection typically extends anterograde, but can extend retrograde from the site of the intimal tear. Aortic dissection is a medical...
- EndocarditisEndocarditisEndocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves . Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or even on intracardiac devices...
- Raised intracranial pressureIntracranial pressureIntracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...
Relationship to heart disease
Recent work suggests that a high pulse pressure is an important risk factor for heart disease. A meta-analysis in 2000, which combined the results of several studies of 8,000 elderly patients in all, found that a 10 mm Hg increase in pulse pressure increased the risk of major cardiovascular complications and mortality by nearly 20%. Heightened pulse pressure is also a risk factor for the development of atrial fibrillationAtrial fibrillation
Atrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...
. The authors of the meta-analysis suggest that this helps to explain the apparent increase in risk sometimes associated with low diastolic pressure, and warn that some medications for high blood pressure may actually increase the pulse pressure and the risk of heart disease.
Self measurement
Pulse pressure readings can be taken on a home monitoring blood pressure device. Most home monitoring blood pressure devices display systolic and diastolic blood pressure and pulse pressure readings. Monitoring at home will measure true pulse and blood pressure and provide a doctor with a log of readings over time.Treatment
If the patient suffers from elevated pulse pressure, treatment may include medications that address this factor, such as an angiotensin-converting enzyme inhibitor (ACE inhibitorACE inhibitor
ACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure...
).
Effect of folic acid
A 2005 study found that 5 mg of folate daily over a three-week period reduced pulse pressure by 4.7 mm of Hg compared with a placebo, and concluded that folic acid is an effective supplement that targets large artery stiffness and may prevent isolated systolic hypertension.See also
- Blood pressureBlood pressureBlood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
- Mean arterial pressureMean arterial pressureThe mean arterial pressure is a term used in medicine to describe an average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.-Calculation:...
- Cold pressor testCold pressor testThe cold pressor test is a cardiovascular test performed by immersing the hand into an ice water container, usually for one minute, and measuring changes in blood pressure and heart rate. Its response is clinically indicative concerning vascular response and pulse excitability.Other measures can...
- HypertensionHypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
- PrehypertensionPrehypertensionPrehypertension is an American classification for cases where a person's blood pressure is elevated above normal but not to the level considered to be hypertension . The seventh report of the Joint National Committee proposed a new definition of blood pressure values below 140/90 mm Hg...
- AntihypertensiveAntihypertensiveThe antihypertensives are a class of drugs that are used to treat hypertension . Evidence suggests that reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from...
- Patent ductus arteriosusPatent ductus arteriosusPatent ductus arteriosus is a congenital disorder in the heart wherein a neonate's ductus arteriosus fails to close after birth. Early symptoms are uncommon, but in the first year of life include increased work of breathing and poor weight gain...