Peripheral vascular occlusion

Serotonin agonists G-protein coupled 5-HT receptors 5-HT3 ion channels cAMP (5-HT-,) t cAMP (5-HT4 7) t PLC (5-HT2) l Release of excitatory neuropeptides l Neurogenic inflammation f vasoconstriction Myocardial infarction, stroke, peripheral vascular occlusion... 

Alpha-receptor-blocking drugs do not seem to be effective in the treatment of peripheral vascular occlusive disease characterized by morphologic changes that limit flow in the vessels. Occasionally, individuals with Raynaud s phenomenon and other conditions involving excessive reversible vasospasm in the peripheral circulation do benefit from prazosin or phenoxybenzamine, although calcium channel blockers may be preferable for most patients. 

Currently, the two antiplatelet agents with proven efficacy are aspirin, which inhibits cyclooxygenase -dependent synthesis of thromboxane Aj (TXj ), and ticlopidine, wdrich blocks the ability of ADP to inhibit stimulated adenyl cyclase. Bodi of these drags have proven prophylactic uses in reducing the risk of thrombo -occlusive and thromboembolic complications for all major arterial beds in individuals with a previous history of such episodes. Controlled trials show that both aspirin and ticlopidine are indicated in the secondary prevention of stroke, myocardial induction and peripheral vascular occlusion. However, there are limitations to their efficacy. No net changes in vascular events are seen with primary prevention. Moreover, antiplatelet drugs do not alter thrombocytopenia or impairment... 

The natural history of the disease is determined by the onset and extent of chronic diabetic complications. Microangiopathic changes are diabetes-specific, causing retinopathy, nephropathy and alterations in the peripheral and autonomous nervous system. Macroangiopathy, which is more typical for Type-II diabetes, leads predominantly to cardiovascular complications with coronary heart disease, myocardial infarction and peripheral vascular occlusion. 

Adachi, H., Irie, T., Uekama, K. et al. Inhibitory effect of prostaglandin El on laurate-induced peripheral vascular occlusive sequelae in rabbits optimized topical formulation with (3-cyclodextrin derivative and penetration enhancer HPE-101. J. Pharm. Pharmacol. 1992, 44, 1033-1035. 

PVO peripheral vascular occlusion pulmonary venous occlusion... 

Gardner AW, Skinner JS, Smith LK. Effects of handrail support on claudication and hemodynamic responses to a single-stage and progressive treadmill protocols in peripheral vascular occlusive disease. Am J Cardiol 1991 68 99-105. 

For the relief of pain arising from spasm of smooth muscle, as in renal or biliary colic, morphine is frequently employed. Other measures including antispasmodics such as atropine, atropine substitutes, theophylline, nitrites, and heat may be employed first however, if they are ineffective, meperidine, methadone, or opiates must be used. Morphine relieves pain only by a central action and may aggravate the condition producing the pain by exaggerating the smooth muscle spasm. Morphine may also be indispensable for the relief of pain due to acute vascular occlusion, whether this be peripheral, pulmonary, or coronary in origin. In painful acute pericarditis, pleurisy, and spontaneous pneumothorax, morphine is likewise indicated. Carefully chosen and properly spaced doses of codeine or morphine may occasionally be necessary in pneumonia to control pain, dyspnea, and restlessness. Traumatic pain arising from fractures, bums, etc., frequently requires morphine. In shock, whether due to trauma, poisons, or other causes, morphine may be required to relieve severe pain. 

Falk E, Unstable angina with fatal outcome dynamic coronary thrombosis leading to infarction and/or sudden death autopsy evidence of recurrent mural thrombosis with peripheral embolization culminating in total vascular occlusion, Circulation 1985 71 699-708. 

Subsets of the hypertensive population The (3-blockers are more effective for treating hypertension in white than in black patients, and in young patients compared to the elderly. [Note Conditions that discourage the use of 3-blockers (for example, severe chronic obstructive lung disease, chronic congestive heart failure, severe symptomatic occlusive peripheral vascular disease) are more commonly found in the elderly and in diabetics.]... 

Tenderness of the branches of the external carotid artery (occipital, facial, superficial temporal) points towards giant cell arteritis. Tenderness of the common carotid artery in the neck can occur in acute carotid occlusion but is more Ukely to be a sign of dissection, or arteritis. Absence of several neck and arm pulses in a young person occurs in Takayasu s arteritis (Ch. 6). Delayed or absent leg pulses suggest coarctation of the aorta or, much more commonly, peripheral vascular disease. Other causes of widespread disease of the aortic arch are atheroma, giant cell arteritis, syphihs, subintimal fibrosis, arterial dissection and trauma. 

Vascular risk factors previous stroke, hypertension, diabetes, contralateral internal cerebral artery occlusion, peripheral vascular disease... 

TIA, transient ischemic attack Ml, myocardial infarction PVD, peripheral vascular disease Cl, confidence interval. Hazard ratios derived from the model are used for the scoring system. The score for the 5-year risk of stroke is the product of the individual scores for each of the risk factors present. The score is converted into a risk using Fig. 27.6. °ln cases of near occlusion, enter degree of stenosis as 85%. 

Peripheral arterial occlusion. Heparin may prevent extension of a thrombus and hasten its recanalisation it is commonly used in the acute phase following thrombosis or embolism. There is no case for treating ischaemic peripheral vascular disease with an oral anticoagulant (for prevention, see Antiplatelet drugs). 

Synthetic PGI2 has been used in arterial occlusive disease as an anti-aggregatory drug (23-28). Adverse effects are common (85%). Headache, fever, nausea, anorexia, diarrhea, pain at the infusion site, and arthralgia are the most prominent. A single study has suggested an increased risk of thromboembolism after the use of iloprost in peripheral vascular disease (29). 

Prinzmetal s vasospastic angina, bronchospastic chronic obstructive pulmonary disease (COPD), asthma, occlusive peripheral vascular disease, type I diabetes mellitus that is prone to hypoglycemia, heart block, and excessive bradycardia are contraindications to /3-blockers. The main side effects of /S-blockers are... 

Tlie fibroblast growtli factors (FGFs) are a large family of pleiotropic growth factors that promote survival, proliferation and differentiation of a variety of cell lines and tissues. Treatment with FGF induces formation of new blood vessels, and improves blood flow and organ function in animal models of peripheral vascular disease and myocardial ischemia. In addition, FGF heatment can reduce infarct size following experimental coronary and cerebral artery occlusion. 

PAOD (Peripheral Artery Occlusive Disease) VEGF gene (Vascular Endothelial Growth Factor) Plasmid DNA Muscle/ endothelial cells in vivo (i.m.) Improved blood flow... 

B. Epinephrine is relatively contraindicated in patients with organic heart disease, peripheral arterial occlusive vascular disease with thrombosis, or ergot poisoning (see p 189). 

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