Заболевания периферических артерий: диагностика, лечение и профилактика.

When narrowing occurs in the heart, it is called coronary artery disease (CAD), and in the brain, it is called cerebrovascular disease. Peripheral artery disease (PAD) is a form of peripheral vascular disease. Vascular refers to both the arteries and veins within the body. PAD differs from peripheral veinous disease. PAD means the arteries are narrowed or blocked—the vessels that carry oxygen rich blood as it moves away from the heart to other parts of the body. Peripheral veinous disease, on the other hand, refers to problems with veins—the vessels that bring the blood back to the heart. The classic symptom is leg pain when walking, which resolves with rest and is known as intermittent claudication. Complications may include an infection or tissue death, which may require amputation; coronary artery disease; or stroke. Up to 50% of people with PAD do not have symptoms. The greatest risk factor for PAD is cigarette smoking. PAD is typically diagnosed by finding an ankle brachial index (ABI) less than 0.90, which is the systolic blood pressure at the ankle divided by the systolic blood pressure of the arm. Duplex ultrasonography and angiography may also be used. Angiography is more accurate and allows for treatment at the same time; however, it is associated with greater risks. For those with intermittent claudication from PAD, stopping smoking and supervised exercise therapy may improve outcomes. Aspirin, which helps with thinning the blood and thus improving blood flow, does not appear to help those with mild disease but is usually recommended for those with more significant disease due to the increased risk of heart attacks. Anticoagulants (blood thinners) such as warfarin show no definitive scientific evidence of benefit in PAD. Surgical procedures used to treat PAD include bypass grafting, angioplasty, and atherectomy. In 2015, about 155 million people had PAD worldwide. It becomes more common with age. In the developed world, it affects about 5.3% of 45 to 50 year olds and 18.6% of 85 to 90 year olds. In 2015, PAD resulted in about 52,500 deaths, which is an increase from the 16,000 deaths in 1990.

Peripheral arterial disease is considered to be a set of chronic or acute syndromes, generally derived from the presence of occlusive arterial disease, which causes inadequate blood flow to the limbs. As previously mentioned, the most common etiology of peripheral artery disease, especially in patients over 40 years old, is atherosclerosis. Additional mechanisms of peripheral artery disease include arterial spasm and fibromuscular dysplasia. The symptoms of claudication ensue when the artery spasms, or clamps down on itself, creating an obstruction. Similar to atherosclerosis, this leads to decreased blood flow to the tissue downstream of the obstruction. Thrombosis, or the formation of a blood clot, usually occurs due to stasis or trauma. An ABI range of 0.90 to 1.40 is considered normal. A person is considered to have PAD when the ABI is ≤ 0.90. However, PAD can be further graded as mild to moderate if the ABI is between 0.41 and 0.90, and severe if the ABI is less than 0.40. These categories can provide insight into the disease course. Individuals with noncompressible arteries have an increased risk of cardiovascular mortality within a two year period. Individuals with suspected PAD with normal ABIs can undergo exercise testing for ABI. A baseline ABI is obtained prior to exercise. The patient is then asked to exercise (usually patients are made to walk on a treadmill at a constant speed) until claudication pain occurs (for a maximum of 5 minutes), after which the ankle pressure is again measured. A decrease in ABI of 15%–20% would be diagnostic of PAD. As such, CT may be considered as an alternative to invasive angiography. An important distinction between the two is that, unlike invasive angiography, assessment of the arterial system with CT does not allow for vascular intervention. Magnetic resonance angiography (MRA) is a noninvasive diagnostic procedure that uses a combination of a large magnet, radio frequencies, and a computer to produce detailed images of blood vessels inside the body. The advantages of MRA include its safety and ability to provide high resolution, three dimensional imaging of the entire abdomen, pelvis, and lower extremities in one sitting.

A guideline from the American College of Cardiology and American Heart Association for the diagnosis and treatment of lower extremity, renal, mesenteric, and abdominal aortic PAD was compiled in 2013, combining the 2005 and 2011 guidelines. For chronic limb threatening ischemia, the ACCF/AHA guidelines recommend balloon angioplasty only for people with a life expectancy of 2 years or less or those who do not have an autogenous vein available. For those with a life expectancy greater than 2 years or who have an autogenous vein, bypass surgery is recommended.

Individuals with PAD have an "exceptionally elevated risk for cardiovascular events and the majority will eventually die of a cardiac or cerebrovascular etiology". Prognosis is correlated with the severity of the PAD as measured by an ABI. Of patients with intermittent claudication, only "7% will undergo lower extremity bypass surgery, 4% major amputations, and 16% worsening claudication", but stroke and heart attack events are elevated, and the "5 year mortality rate is estimated to be 30% (versus 10% in controls)". 70%–80% of affected individuals are asymptomatic; only a minority ever require revascularization or amputation. Peripheral artery disease affects one in three diabetics over the age of 50. In the US, it affects 12–20 percent of Americans age 65 and older. Around 10 million Americans have PAD. Despite its prevalence and implications for cardiovascular risk, there are still low levels of awareness of risk factors and symptoms, with 26% of the population in the US reported to have knowledge of PAD. In 2000, among people aged 40 years and older in the United States, rates of PAD were 4.3%. Rates were 14.5% for people aged 70 years or over. Within age groups, rates were generally higher for women than men. Non Hispanic blacks had a rate of 7.9% compared to 4.4% in Non Hispanic whites and 3.0% (1.4%–4.6%) in Mexican Americans. The Diabetes Control and Complications Trial and the UK Prospective Diabetes Study trials in people with type 1 and type 2 diabetes, respectively, demonstrated that glycemic control is more strongly associated with microvascular disease than macrovascular disease. Pathologic changes occurring in small vessels may be more sensitive to chronically elevated glucose levels than atherosclerosis occurring in larger arteries.

Research is being done on therapies to prevent the progression of PAD. In those who have developed critically poor blood flow to the legs, the benefit of autotransplantation of autologous mononuclear cells is unclear. Only one randomized controlled trial has been conducted comparing vascular bypass to angioplasty for the treatment of severe PAD. The trial found no difference in amputation free survival between vascular bypass and angioplasty at the planned clinical endpoint, but the trial has been criticized as being underpowered, limiting endovascular options, and comparing inappropriate endpoints. As of 2017, two randomized clinical trials are being conducted to better understand the optimal revascularization technique for severe PAD and critical limb ischemia (CLI), the BEST CLI (Best Endovascular Versus Best Surgical Therapy for Patients With Critical Limb Ischemia) Trial and the BASIL 2 (Bypass Versus Angioplasty in Severe Ischaemia of the Leg – 2 )Trial. In 2011, pCMV vegf165 was registered in Russia as the first in class gene therapy drug for the treatment of PAD, including the advanced stage of critical limb ischemia.