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In 2008, the US had an estimate of 16 million atherosclerotic heart disease and 5.8 million strokes. Cardiovascular diseases that were caused by arteriosclerosis also caused almost 812,000 deaths in 2008, more than any other cause, including cancer. About 1.2 million Americans are predicted to have a heart attack each year.
Risk factors contributing to PAD are the same as those for atherosclerosis:
- Smoking – tobacco use in any form is the single most important modifiable cause of PAD internationally. Smokers have up to a tenfold increase in relative risk for PAD in a dose-response relationship. Exposure to second-hand smoke from environmental exposure has also been shown to promote changes in blood vessel lining (endothelium) which is a precursor to atherosclerosis. Smokers are 2 to 3 times more likely to have lower extremity peripheral arterial disease than coronary artery disease. More than 80%-90% of patients with lower extremity peripheral arterial disease are current or former smokers. The risk of PAD increases with the number of cigarettes smoked per day and the number of years smoked.
- Diabetes mellitus – causes between two and four times increased risk of PAD by causing endothelial and smooth muscle cell dysfunction in peripheral arteries. The risk of developing lower extremity peripheral arterial disease is proportional to the severity and duration of diabetes.
- Dyslipidemia – a high level of low-density lipoprotein (LDL cholesterol) and a low level of high-density lipoprotein (HDL cholesterol) in the blood) - elevation of total cholesterol, LDL cholesterol, and triglyceride levels each have been correlated with accelerated PAD. Correction of dyslipidemia by diet and/or medication is associated with a major improvement in rates of heart attack and stroke.
- Hypertension – elevated blood pressure is correlated with an increase in the risk of developing PAD, as well as in associated coronary and cerebrovascular events (heart attack and stroke). Hypertension increased the risk of intermittent claudication 2.5- to 4-fold in men and women, respectively.
- Risk of PAD also increases in individuals who are over the age of 50, male, obese, heart attack, or stroke or with a family history of vascular disease.
- Other risk factors which are being studied include levels of various inflammatory mediators such as C-reactive protein, fibrinogen, hyperviscosity, hypercoagulable state.
Arteriosclerosis is the thickening, hardening and loss of elasticity of the walls of arteries. This process gradually restricts the blood flow to one's organs and tissues and can lead to severe health risks brought on by atherosclerosis, which is a specific form of arteriosclerosis caused by the buildup of fatty plaques, cholesterol, and some other substances in and on the artery walls.
Peripheral arterial disease is more common in the following populations of people:
- All people who have leg symptoms with exertion (suggestive of claudication) or ischemic rest pain.
- All people aged 65 years and over regardless of risk factor status.
- All people between the age of 50 to 69 and who have a cardiovascular risk factor (particularly diabetes or smoking).
- Age less than 50 years, with diabetes and one other atherosclerosis risk factor (smoking, dyslipidemia, hypertension, or hyperhomocysteinemia).
- Individuals with an abnormal lower extremity pulse examination.
- Those with known atherosclerotic coronary, carotid, or renal artery disease.
- All people with a Framingham risk score 10%-20%
- All people who have previously experienced chest pain
The prevalence of Mönckeberg's arteriosclerosis increases with age and is more frequent in diabetes mellitus, chronic kidney disease, systemic lupus erythematosus, chronic inflammatory conditions, hypervitaminosis D and rare genetic disorders, such as Keutel syndrome. The prevalence of Monckeberg's arteriosclerosis in the general population has been estimated as 1.5; however the validity of this criterion is questionable.
Often Mönckeberg's arteriosclerosis is discovered as an incidental finding in an X-ray radiograph, on mammograms, in autopsy, or in association with investigation of some other disease, such as diabetes mellitus or chronic kidney disease. Typically calcification is observed in the arteries of the upper and lower limb although it has been seen in numerous other medium size arteries. In the radial or ulnar arteries it can cause "pipestem" arteries, which present as a bounding pulse at the end of the calcific zone. It may also result in "pulselessness." Epidemiological studies have used the ratio of ankle to brachial blood pressure (ankle brachial pressure index, ABPI or ABI) as an indicator of arterial calcification with ABPI >1.3 to >1.5 being used as a diagnostic criterion depending on the study.
Risk factors for thromboembolism, the major cause of arterial embolism, include disturbed blood flow (such as in atrial fibrillation and mitral stenosis), injury or damage to an artery wall, and hypercoagulability (such as increased platelet count). Mitral stenosis poses a high risk of forming emboli which may travel to the brain and cause stroke. Endocarditis increases the risk for thromboembolism, by a mixture of the factors above.
Atherosclerosis in the aorta and other large blood vessels is a common risk factor, both for thromboembolism and cholesterol embolism. The legs and feet are major impact sites for these types. Thus, risk factors for atherosclerosis are risk factors for arterial embolisation as well:
- advanced age
- cigarette smoking
- hypertension (high blood pressure)
- obesity
- hyperlipidemia, e.g. hypercholesterolemia, hypertriglyceridemia, elevated lipoprotein (a) or apolipoprotein B, or decreased levels of HDL cholesterol)
- diabetes mellitus
- Sedentary lifestyle
- stress
Other important risk factors for arterial embolism include:
- recent surgery (both for thromboembolism and air embolism)
- previous stroke or cardiovascular disease
- a history of long-term intravenous therapy (for air embolism)
- Bone fracture (for fat embolism)
A septal defect of the heart makes it possible for paradoxical embolization, which happens when a clot in a vein enters the right side of the heart and passes through a hole into the left side. The clot can then move to an artery and cause arterial embolisation.
Arterial stiffness occurs as a consequence of biological aging and arteriosclerosis. Inflammation plays a major role in arteriosclerosis development, and consequently it is a major contributor in large arteries stiffening. Increased arterial stiffness is associated with an increased risk of cardiovascular events such as myocardial infarction and stroke, the two leading causes of death in the developed world. The World Health Organisation predicts that in 2010, cardiovascular disease will also be the leading killer in the developing world and represents a major global health problem.
Several degenerative changes that occur with age in the walls of large elastic arteries are thought to contribute to increased stiffening over time, including the mechanical fraying of lamellar elastin structures within the wall due to repeated cycles of mechanical stress; changes in the kind and increases in content of arterial collagen proteins, partially as a compensatory mechanism against the loss of arterial elastin and partially due to fibrosis; and crosslinking of adjacent collagen fibers by advanced glycation endproducts (AGEs).
When the heart contracts it generates a pulse or energy wave that travels through the circulatory system. The speed of travel of this pulse wave (pulse wave velocity (PWV)) is related to the stiffness of the arteries. Other terms that are used to describe the mechanical properties of arteries include elastance, or the reciprocal (inverse) of elastance, compliance. The relationship between arterial stiffness and pulse wave velocity was first predicted by Thomas Young in his Croonian Lecture of 1808 but is generally described by the Moens–Korteweg equation or the Bramwell–Hill equation. Typical values of PWV in the aorta range from approximately 5 m/s to >15 m/s.
Measurement of aortic PWV provides some of the strongest evidence concerning the prognostic significance of large artery stiffening. Increased aortic PWV has been shown to predict cardiovascular, and in some cases all cause, mortality in individuals with end stage renal failure, hypertension, diabetes mellitus and in the general population. However, at present, the role of measurement of PWV as a general clinical tool remains to be established. Devices are on the market that measure arterial stiffness parameters (augmentation index, pulse wave velocity). These include the Complior, CVProfilor, PeriScope, Hanbyul Meditech, Mobil-O-Graph NG, BP Plus (Pulsecor), PulsePen, BPLab Vasotens, Arteriograph, Vascular Explorer, and SphygmoCor.
70% of patients with carotid arterial dissection are between the ages of 35 and 50, with a mean age of 47 years.
According to the United States Renal Data System (USRDS), hypertensive nephropathy accounts for more than one-third of patients on hemodialysis and the annual mortality rate for patients on hemodialysis is 23.3%.
Haemodialysis is recommended for patients who progress to end-stage kidney disease (ESKD) and hypertensive nephropathy is the second most common cause of ESKD after diabetes.
Patient prognosis is dependent on numerous factors including age, ethnicity, blood pressure and glomerular filtration rate. Changes in lifestyle factors, such as reduced salt intake and increased physical activity have been shown to improve outcomes but are insufficient without pharmacological treatment.
An arterial embolism is caused by one or more emboli getting stuck in an artery and blocking blood flow, causing ischemia, possibly resulting in infarction with tissue death (necrosis). Individuals with arterial thrombosis or embolism often develop collateral circulation to compensate for the loss of arterial flow. However, it takes time for sufficient collateral circulation to develop, making affected areas more vulnerable for sudden occlusion by embolisation than for e.g. gradual occlusion as in atherosclerosis.
The incidence of hypertensive nephropathy varies around the world. For instance, it accounts for as many as 25% and 17% of patients starting dialysis for end-stage kidney disease in Italy and France respectively. Contrastingly, Japan and China report only 6 and 7% respectively. Since the year 2000, nephropathy caused by hypertension has increased in incidence by 8.7% In reality, these figures may be even higher, as hypertension is not always reported as the specific cause of kidney disease.
It has been recognized that the incidence of hypertensive nephropathy varies with ethnicity. Compared to Caucasians, African Americans in the USA are much more likely to develop hypertensive nephropathy. Of those who do, the proportion who then go on to develop end-stage renal failure is 3.5 times higher than in the Caucasian population. In addition to this, African Americans tend to develop hypertensive nephropathy at a younger age than Caucasians (45 to 65, compared to >65).
Once considered uncommon, spontaneous carotid artery dissection is an increasingly recognised cause of stroke that preferentially affects the middle-aged.
The incidence of spontaneous carotid artery dissection is low, and incidence rates for internal carotid artery dissection have been reported to be 2.6 to 2.9 per 100,000.
Observational studies and case reports published since the early 1980s show that patients with spontaneous internal carotid artery dissection may also have a history of stroke in their family and/or hereditary connective tissue disorders, such as Marfan syndrome, Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease, pseudoxanthoma elasticum, fibromuscular dysplasia, and osteogenesis imperfecta type I. IgG4-related disease involving the carotid artery has also been observed as a cause.
However, although an association with connective tissue disorders does exist, most people with spontaneous arterial dissections do not have associated connective tissue disorders. Also, the reports on the prevalence of hereditary connective tissue diseases in people with spontaneous dissections are highly variable, ranging from 0% to 0.6% in one study to 5% to 18% in another study.
Internal carotid artery dissection can also be associated with an elongated styloid process (known as Eagle syndrome when the elongated styloid process causes symptoms).
The thrombi may dislodge and may travel anywhere in the circulatory system, where they may lead to pulmonary embolus, an acute arterial occlusion causing the oxygen and blood supply distal to the embolus to decrease suddenly. The degree and extent of symptoms depend on the size and location of the obstruction, the occurrence of clot fragmentation with embolism to smaller vessels, and the degree of peripheral arterial disease (PAD).
- Thromboembolism (blood clots)
- Embolism (foreign bodies in the circulation, e.g. amniotic fluid embolism)
Traumatic injury to an extremity may produce partial or total occlusion of a vessel from compression, shearing or laceration. Acute arterial occlusion may develop as a result of arterial dissection in the carotid artery or aorta or as a result of iatrogenic arterial injury (e.g., after angiography).
Pseudohypertension, also known as pseudohypertension in the elderly, noncompressibility artery syndrome, and Osler's sign of pseudohypertension is a falsely elevated blood pressure reading obtained through sphygmomanometry due to calcification of blood vessels which cannot be compressed. There is normal blood pressure when it is measured from within the artery. This condition however is associated with significant cardiovascular disease risk.
Because the stiffened arterial walls of arteriosclerosis do not compress with pressure normally, the blood pressure reading is theoretically higher than the true intra-arterial measurement.
To perform the test, one first inflates the blood pressure cuff above systolic pressure to obliterate the radial pulse. One then attempts to palpate the radial artery, a positive test is if it remains palpable as a firm "tube".
It occurs frequently in the elderly irrespective of them being hypertensive, and has moderate to modest intraobserver and interobserver agreement. It is also known as "Osler's maneuver".
The sign is named for William Osler.
Thrombosis prevention is initiated with assessing the risk for its development. Some people have a higher risk of developing thrombosis and its possible development into thromboembolism. Some of these risk factors are related to inflammation. "Virchow's triad" has been suggested to describe the three factors necessary for the formation of thrombosis: stasis of blood, vessel wall injury, and altered blood coagulation. Some risk factors predispose for venous thrombosis while others increase the risk of arterial thrombosis.
Most commonly, intermittent (or vascular or arterial) claudication is due to peripheral arterial disease which implies significant atherosclerotic blockages resulting in arterial insufficiency. It is distinct from neurogenic claudication, which is associated with lumbar spinal stenosis. It is strongly associated with smoking, hypertension, and diabetes.
The main causes of thrombosis are given in Virchow's triad which lists thrombophilia, endothelial cell injury, and disturbed blood flow.
Arterial insufficiency ulcers (also known as Ischemic ulcers or Ischemic wounds) are mostly located on the lateral surface of the ankle or the distal digits. They are commonly caused by peripheral artery disease (PAD).
The prognosis of pulmonary arterial hypertension (WHO Group I) has an "untreated" median survival of 2–3 years from time of diagnosis, with the cause of death usually being right ventricular failure (cor pulmonale). A recent outcome study of those patients who had started treatment with bosentan (Tracleer) showed that 89% patients were alive at 2 years. With new therapies, survival rates are increasing. For 2,635 patients enrolled in The Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL Registry) from March 2006 to December 2009, 1-, 3-, 5-, and 7-year survival rates were 85%, 68%, 57%, and 49%, respectively. For patients with idiopathic/familial PAH, survival rates were 91%, 74%, 65%, and 59%. Levels of mortality are very high in pregnant women with severe pulmonary arterial hypertension (WHO Group I). Pregnancy is sometimes described as contraindicated in these women.
The epidemiology of IPAH is about 125–150 deaths per year in the U.S., and worldwide the incidence is similar to the U.S. at 4 cases per million. However, in parts of Europe (France) indications are 6 cases per million of IPAH. Females have a higher incidence rate than males (2–9:1).
Other forms of PH are far more common. In systemic scleroderma, the incidence has been estimated to be 8 to 12% of all patients; in rheumatoid arthritis it is rare. However, in systemic lupus erythematosus it is 4 to 14%, and in sickle cell disease, it ranges from 20 to 40%. Up to 4% of people who suffer a pulmonary embolism go on to develop chronic thromboembolic disease including pulmonary hypertension. A small percentage of patients with COPD develop pulmonary hypertension with no other disease to explain the high pressure. On the other hand, obesity-hypoventilation syndrome is very commonly associated with right heart failure due to pulmonary hypertension.
These ulcers are difficult to heal by basic wound care and require advanced therapy, such as hyperbaric oxygen therapy or bioengineered skin substitutes. If not taken care of in time, there are very high chances that these may become infected and eventually may have to be amputated. Individuals with history of previous ulcerations are 36 times more likely to develop another ulcer.
CREST syndrome can be noted in up to 10% of patients with primary biliary cirrhosis.