Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0151744 (myocardial ischemia)
 31,282 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the presence of regional myocardial ischemia, a 20% decrease in systemic arterial pressure following nitroprusside caused a 25% decrease in coronary perfusion pressure in animals with normal left ventricular end-diastolic pressures. This pressure decrement resulted in a significant decrease in the shortening of the regionally ischemic segment during the ejection phase of systole. A comparable arterial pressure drop of 21% with nitroprusside infusion during ischemia in the animals with elevated diastolic pressures caused a similar 28% decrease in coronary perfusion pressure, but resulted in a simultaneous increase in regional shortening. For the entire group there was no significant change in stroke volume. Even in the 11 animals where stroke volume increased, systolic regional shortening increased in only 4. An increase in stroke volume cannot be used to infer a parallel increase in the performance of a regionally ischemic segment. Nitroprusside appears to improve regional performance only in the presence of severe failure.
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PMID:Effects of sodium nitroprusside on function of regional ischemic myocardium. 75 85

Cafergot is a combination of ergotamine tartrate and caffeine and may cause symptoms of peripheral vascular insufficiency. Iatrogenic ergotism should be suspected in any patient exhibiting ischemic symptoms while receiving this medication. Progression to fulminant necrosis and gangrene can occur. Two cases are presented and the management reviewed. This effect of ergotamine tartrate and caffeine may be an idiosyncratic hypersensitivity reaction with therapeutic doses or may result from excessive medication. Iatrogenic ergotism occurs most often in women in their mid-thirties with migraine syndrome. By alpha-adrenergic agonism, as well as by possible interactions with prostaglandins, calcium, and serotonin, ergotamine causes vasoconstriction of both arteries and veins. The angiographic pattern of spasm, collateral formation, and intravascular thrombi is typical. Treatment of ergotism depends on the severity of the symptoms and the possibility of gangrene. Discontinuation of ergotamine, cigarette smoking, and caffeine may be all that is necessary in most patients. Nitroprusside is the drug of choice in the treatment of acute vascular insufficiency from ergotism, but in a less urgent situation, prazosin has also been effective. Intra-arterial balloon dilatation has also been helpful. Other forms of therapy have been supportive and the results inconsistent. Cafergot should be used with extreme caution in patients with renal or hepatic failure, peripheral vascular disease, or pregnancy. Relative contraindications include hypertension, ischemic heart disease, and Raynaud's phenomenon.
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PMID:Recognition and treatment of arterial insufficiency from cafergot. 372 91

Hypertension following aorta-coronary bypass operations can contribute to myocardial ischemia. Nitroprusside therapy will reduce afterload, preload, and coronary perfusion pressure. Since both hypertension and its treatment can result in ischemic injury, nitroprusside must be carefully titrated to optimize cardiac function and metabolism. Thirty-one patients undergoing elective coronary bypass grafting were studied during a hypertensive episode (mean arterial pressure [MAP] = 119 +/- 18 mm Hg) and during nitroprusside therapy at an MAP of 97 +/- 11 mm Hg and at an MAP of 80 +/- 11 mm Hg (normotension). Nitroprusside also produced a significant (p less than 0.05) decrease in left atrial pressure (LAP), left ventricular end-diastolic volume index (EDVI) (stroke index divided by ejection fraction by nuclear angiography), stroke index, and stroke work index (SWI). Cardiac lactate extraction (LEx) and the ratio LEx/SWI increased (p less than 0.05) with the initial nitroprusside therapy, but lactate production resulted when the MAP was lowered to 80 mm Hg. Volume loading studies were performed during hypertension in four patients and during nitroprusside therapy in 15 patients. Neither performance nor compliance was significantly altered at an MAP of 97 mm Hg, but compliance decreased at normotension. Both hypertension and its treatment can result in inadequate myocardial metabolism. Nitroprusside should be titrated to maintain MAP between 90 and 100 mm Hg.
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PMID:Effects of postoperative hypertension and its treatment. 660 14

Hypertensive crisis is a rare condition with increased blood pressure and evidence of new or progressive severe end-organ damage. The patients should be admitted to hospital, and the blood pressure reduced gradually. Blood pressure should not be normalized, but a reduction in mean arterial pressure of 20-25% or to a diastolic blood pressure > 100-110 mmHg should be achieved. Patients at particular risk for further complications are elderly, patients with hypovolaemia, renal insufficiency, ischaemic heart disease and patients with neurological deficits. The ideal antihypertensive drug for any form of hypertensive crisis does not exist. If the patient can cooperate with oral treatment, nifedipine may be used, usually administered as capsules of 10 mg orally, producing a rapid and safe reduction in blood pressure of 25% within 10-15 minutes with a maximal action after 30-60 minutes. The dose may be repeated after 30 minutes in case of insufficient blood pressure response. Hypotension is rare. Nifedipine in combination with nitroglycerine is of special benefit in hypertensive pulmonary oedema. In cases of treatment failure or if the patient cannot cooperate with oral treatment, the choice of drug lies between labetalol and sodium nitroprusside. Nitroprusside is administered as continuous intravenous infusion, the drug is safe to use and is recommended in conditions where reduction of blood pressure must be performed with extreme caution such as in cases of cerebral infarction and intracranial hemorrhage. Infusion of nitroprusside for more than 48-72 hours is inexpedient because the metabolites of nitroprusside need monitoring as well. Parenteral drug therapy with labetalol is more simple than treatment with nitroprusside, but at the same time somewhat more difficult to titrate. Nitroglycerine is very suitable in moderate hypertension and ischaemic heart disease, but in severe hypertension with heart disease nitroprusside is the treatment of choice. Loop diuretics should not be used as first-line drugs, but only in conditions with evidence of volume-overload. Patients with hypertensive crisis most often show volume depletion which is aggravated by loop diuretics, therefore they should not be used routinely. When the blood pressure has been stabilized, an oral antihypertensive drug should be started concomitantly to a gradual reduction of the initial parenteral drug therapy.
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PMID:[Hypertensive crises. 2. Treatment]. 875 95

Nitroglycerin and the long-acting nitrates have been used in cardiovascular medicine for >100 years. Nitrates are widely utilized for the various anginal syndromes and are also used in congestive heart failure and patients with left ventricular dysfunction. The potential mechanisms for relief of myocardial ischemia with nitrates are multiple. The nitrovasodilators are a related group of drugs that result in the formation of nitric oxide (NO) within vascular smooth muscle cells. NO stimulates the enzyme guanylate cyclase, which results in increases in cyclic guanosine monophosphate and vasodilation. In the presence of atherosclerosis, endothelial dysfunction is ubiquitous and associated with decreased NO availability, probably due to increased destruction of NO by free radical anions. Nitrovasodilators, including the nitrates, supply exogenous NO to the vascular wall and improve the vasodilator state. When nitrates are administered, endothelial-dependent stimuli cause relaxation rather than constriction in the setting of endothelial dysfunction. Nitrates also have antiplatelet effects, and recent evidence confirms that these drugs decrease platelet aggregation and thrombosis formation. This may play an important role in the therapy of acute unstable myocardial ischemia, including unstable angina and myocardial infarction. Nitrate hemodynamic effects have been long known. They are primarily modulated through a decrease in myocardial work that results from smaller cardiac chambers operating with lower systolic and diastolic pressures. These changes are caused by a redistribution of the circulating blood volume away from the heart to the venous capacitance system, with a fall in venous return to the heart. The afterload or arterial effects of nitrates are also useful in decreasing myocardial oxygen consumption. Considerable evidence confirms a variety of mechanisms whereby nitrates increase coronary blood flow, including epicardial coronary artery dilation, stenosis enlargement, enhanced collateral size and flow, improvement of endothelial dysfunction, and prevention or reversal of coronary artery vasoconstriction. These effects help increase nutrient coronary blood flow to zones of myocardial ischemia. Recent data with the nitroglycerin patch confirm that myocardial ischemia is decreased after nitrate administration. Nitroprusside, another nitrovasodilator, is a commonly used intravenous agent for lowering arterial pressure and left ventricular filling pressure. This drug is highly effective for the treatment of acute or severe hypertension and congestive heart failure. However, there are data suggesting that nitroprusside may be deleterious in the presence of acute myocardial ischemia, perhaps by shunting blood away from zones of jeopardized myocardial blood flow. Therefore, nitroprusside cannot be recommended to treat myocardial ischemia; intravenous nitroglycerin should be used in this context.
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PMID:Beneficial actions of nitrates in cardiovascular disease. 863 24