CHRONIC ARTERIAL ISCHEMIA

A. VAYDA

department of surgery with urology and anesthesiology

CHRONIC ARTERIAL ISCHEMIAAtherosclerosis Obliterating endarteritis (obliterative thromboangitis, thrombangiitis obliterans) Aorto-arteritis (Takayashu arteritis )Diabetes mellitusRaynaud's disease Group of hypersensitive angiites, autoimmune angiopathy (mixed cryoglobulinemia, arteritis as a result of collagenous diseases: nodular periarteritis, dermatomyositis, systemic scleroderma) Acute and blunt trauma with artherothrombosis

Peripheral arterial disease generally results from atherosclerotic occlusion of the lower-limb arteries.

ATHEROSCLEROSIS OBLITERANS

Atherosclerosis obliterans of the inferior extremities is a widespread disease, with a specific lesion of arteries of elastic and muscular-elastic types as a focal growth of connecting tissue with a lipid infiltration of intima. It results in disturbances of a circulation in tissues.

EpidemiologySymptomless peripheral arterial disease is very common, with a prevalence on non-invasive testing of up to 25 % in men older than 50 years.Population surveys have reported a prevalence of intermittent claudication between 1 % and 7 % for men aged 50-75 years. Symptomatic peripheral arterial disease is two to five times more common in men than in women.

The incidence of chronic critical ischaemia is around 50-100 per 100000 per year, which translates to about 20000 patients presenting per year in the UK.

Natural course As a result of the generalised nature of the arterial disease, patients with intermittent claudication have a mortality rate 2-3 times higher than age-matched, sex-matched controls. Men with intermittent claudication have 5-year cumulative mortality rates of around 15 %. 70 % of patients dye in 5-year period after the amputation. Among prognostic factors which associate with increasing of mortality, consider the severity of lower-limb ischaemia, presence of coronary or cerebrovascular disease, hypertension, and diabetes mellitus.

Natural courseCritical ischaemia is associated with a high rate of death and limb loss. Very poor outcomes have been reported for patients with chronic critical ischaemia treated conservatively. In one report of more than 100 patients with critical ischaemia, unsuitable for reconstruction, only 28 % of patients were alive without amputation at 1 year.

Etiology (risk factors)

•Smoking•Obesity •Hyperlipidemia•Diabetes mellitus•Hypertension

Risk factorsLow density lipoproteins modification

Damage of endothelium

Increase of lipid peroxidationIncrease of inflammatory

mediators

Block of creation and biologic properties of NO Monocyte and macrophag activation

IL-1, IL-6, growth factors release

Migration and proliferation of smooth muscle cells in intima

Exudation, proliferation, fibrosis, calcinosis

Arterial stenosis

Collateral compensation

Decreasing of intravascular pressure

Microcirculatory disturbances

Tissue acidosis Capillary atony

Hypoxia

Arterio-venous fistula

Increase of blood coagulation

Edema Pain Trophic changes

Necrosis and gangrene

Pathogenesis

І stage – complete compensation (coldness, fatigue, paresthesias); ІІ stage –functional circulatory insufficiency (a leading sign - intermittent claudication);

•II A st. - intermittent claudication 200-500 m•II B st. - intermittent claudication less than 200 m

ІІІ stage – ischemia of extremity at rest (a leading sign – rest or night pain);

•III A st. - ankle pressure less than 50 mm Hg•III B st. - ankle pressure less than 30 mm Hg

ІV stage – considerably expressed destruction of tissues of the distal parts of extremity (ulcers, necrosis, gangrene).

Classification(according to A. Fountain, 1954)

Symptomatology and clinical course

•Coldness•Intermittent claudication•Color changes of skin•Impaired pulsation•Trophic changes•Edema •Ulceration and gangrene

Lerishe’s syndrome •Absence of pulsation•Intermittent claudication•Impotence

•Severe pain at rest •Ulceration or gangrene •A low ankle arterial pressure (<50 mm hg)•Permanent sitting position for pain relief•Ortostatic edema of lower leg.

Patients with critical ischaemia inevitably require amputation if treated conservatively, whereas more than 25 % of those with subcritical ischaemia retain the leg without intervention.

Critical ischaemia

Diagnostic

•Complaints, anamnesis •Examination of extremities. •Palpation, auscultation of vessels. •Coagulogram. •Biochemical analysis of blood (cholesterol, triglycerides, lipids). •Rheovasography. •Dopplerography of vessels. •Arteriography.

Duplex imaging

Measurement of the sphygmomanometer cuff pressure at which blood flow becomes detectable by doppler in the posterior tibial artery and dorsalis pedis artery gives a valuable guide to the severity of arterial disease. Readings are commonly expressed as the ankle/brachial pressure index (ABPI). This index allows comparison between patients and, more importantly, sequential recordings can monitor disease progress. Intermittent claudication is commonly associated with an ABPI of between 0.5 and 0.9. Critical ischaemia is usually associated with an ankle pressure of less than 50 mm Hg.

Doppler ankle pressure

Traditionally, surgical or endovascular intervention has been considered only after intra-arterial angiography. By means of digital subtraction, high-quality images are obtained and small volumes of contrast are required. However, angiography is an invasive procedure, associated with complications, and bed rest is required after the procedure. Common practice in some vascular units is now to plan angioplasty and even peripheral revascularisation on the basis of duplex imaging alone. Intraoperative angiography may be useful to visualise calf arteries in patients with severe proximal disease since the flow in these vessels is difficult to detect with duplex.

Angiography

•Magnetic resonance angiography•Spiral computed tomographic angiography

Newer imaging methods

•Magnetic resonance angiography•Spiral computed tomographic angiography

Newer imaging methods

Differential diagnosis

•Endarteritis obliterans•Ishioradiculitis•Diabetic angiopathy•Nonspecific aorto-arteriitis

Complications

•Arterial thrombosis•Aneurysm•Gangrene

Arterial thrombosis

AneurysmPulsating elastic formation with systolic murmur over it

Gangrene

Conservative therapyThe goal of the treatment of obliterating endarteriitis consists of the renewal or improvement of capillary circulation. This problem could be solved by: 1) improving of blood rheology; 2) improving of peripheral macrohemodynamics, particularly by reducing of the arterio-venous dumping of blood (thus the application of spasmolytics is categorically contraindicated); 3) normalization of interaction between endothelium and formed elements of blood.

•Prostaglandins•Antiaggregants•Stimulators of metabolism•Stimulators of rheology

Surgery

•Endarterectomy

Surgery•Autovenous bypass

Surgery•Prosthetic graft repairing

Surgery

•Plastic of deep femoral artery

Surgery

•Rotation osteoperforation of tibial bone