Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prerequisite in establishing the indication for coronary arteriography is low mortality and morbidity of the procedure. Mortality is about 1%, major complications are myocardial infarction (1.5 to 2%) and cerebral embolism (less than 1%). These low complication rates are generally achieved only in institutions which perform at least 400 procedures per year. Coronary arteriography is indicated in the following groups of patients: patients with angina pectoris aged below 45; patients over 45 with sudden worsening of angina, angina pectoris uncontrolled by medication (impaired quality of life) and cases where there is objective evidence of severe ischemia on exercise though angina is mild; recurrence of angina or positive stress ECG after myocardial infarction; following an episode of unstable angina; following resuscitation due to ventricular fibrillation; suspected Prinzmetal angina; postinfarction aneurysm with signs of heart failure; candidates for valve surgery aged over 45. Coronary arteriography is also performed to evaluate the result of bypass surgery, in patients with unclear diagnosis exposed to occupational hazards, and in acute myocardial infarction (thrombolysis, ventricular septal rupture, acute mitral regurgitation). The main indications for radioisotope studies (Tl-201 myocardial scintigraphy and radionuclide angiography during dynamic exercise) are detection and localization of ischemic zones and scars in patients with known coronary disease, and evaluation of the result of coronary artery bypass surgery. Less frequent indications are, today, atypical chest pain and uninterpretable ECG, and asymptomatic patients with abnormal stress ECG. 2-d echocardiography is the most widely used noninvasive technique for qualitative assessment of regional wall motion disorders at rest. 3800 coronary arteriographies are performed yearly in the public hospitals of Switzerland.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Indications for coronary angiography and other special studies]. 660 28

To examine the angiographic features of vasospastic angina associated with ST segment depression, we attempted to analyze the coronary arteriograms of 12 patients who exhibited ST segment depression during the ergonovine provocative test. Right and left coronary arteriograms were obtained successively within a short period when the ergonovine administration revealed ST segment depression. Eight out of 12 patients showed non-total spastic obstructions in one of the major coronary arteries. Among them, a collateral augmentation was found only in one patient. Two cases exhibited the well-developed collateral channels during non-anginal periods and in one case a collateral blood supply was reduced by the spasm occurred in the donating artery. In another one, the collateral circulation did not change during anginal period. Three out of 4 patients who showed total spastic obstructions demonstrated transiently augmented collateral circulation which was supplied by the non-spastic artery. These findings may indicate that ST segment depression during coronary artery spasm could attribute to a subendocardial ischemia caused by an incomplete occlusion of large coronary artery and transient reduction or augmentation of collateral blood flow.
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PMID:Arteriographic features of angina pectoris associated with ST segment depression during coronary arterial spasm. 665 93

Alternans of the ST segment is frequent in Prinzmetal's angina and is referred to a dyshomogeneity of myocardial refractoriness during ischemia. Reports of this phenomenon in myocardial infarction are, on the contrary, extremely rare. A case of alternans of the ST segment in a man with myocardial infarction is described. Based on the previous experimental reports, the hypothesis is advanced that delayed and blocked electrical activity of the ischemic area may be responsible for the event observed. This phenomenon is probably not infrequent in myocardial infarction.
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PMID:[ST segment alternams in myocardial infarct: apropos of a case]. 666 16

M-mode echocardiograms were recorded in 12 patients with Prinzmetal's angina during 29 episodes of transient myocardial ischemia at rest (18 spontaneous and 11 ergonovine-induced). At peak ST segment elevation a regional mechanical impairment was observed in the interventricular septum during 23 episodes of angina and in the posterior wall during six episodes. In the 18 spontaneous episodes the left ventricular ischemic wall, when compared to the basal state, was found to have a significant reduction in motion (-76.3 +/- 9.1%) (mean +/- SEM), in diastolic thickness (-11.7 +/- 2.5%), and in percent systolic thickening (-88.0 +/- 5.6%). Increase in left ventricular end-diastolic diameter (+13.1 +/- 2.1%) and decrease in percent fractional shortening (-38.1 +/- 3.7%) were also observed. When ST segment was back to the isoelectric line, a transient overshoot in regional left ventricular function was observed. In induced episodes statistically significant changes could be detected by M-mode echocardiography even before appearance of ST segment elevation and anginal pain. No significant difference was found in type or degree of mechanical impairment between induced and spontaneous episodes. Therefore, in patients with Prinzmetal's angina: (1) M-mode echocardiography allows detection of mechanical changes due to transient myocardial ischemia; and (2) mechanical impairment occurs earlier than clinical (pain) and electrocardiographic (ST segment elevation) signs of transmural ischemia.
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PMID:Transient changes in left ventricular mechanics during attacks of Prinzmetal's angina: an M-mode echocardiographic study. 669 89

Because ergonovine appears to produce coronary contractions by a serotonergic (5-HT) mechanism, we attempted to prevent ergonovine-induced ischemia in patients with vasospastic angina by pretreatment with ketanserin, a new selective 5-HT blocker. We studied seven patients with consistently positive results of ergonovine testing (ST segment elevation in three and ST segment depression in four). Ergonovine testing was performed before and after a bolus of 10 mg of ketanserin (all patients) and infusion of 2 to 4 mg/hr for 8 hr (six patients). To assess 5-HT blockade during ketanserin infusion, the constrictor response of hand veins to 5-HT was tested before and after ketanserin. Despite evidence of 5-HT blockade in hand veins, ergonovine-induced ischemia was not prevented by ketanserin in any patient, and there was no significant change in the dose of ergonovine required to provoke ischemia. In one patient, four spontaneous episodes of ST segment elevation occurred during infusion of ketanserin. The plasma concentrations of ketanserin at the time of ergonovine testing ranged from 61 to 127 ng/ml (mean 102) and were well above those that completely inhibit canine coronary 5-HT contractions in vitro. Although human coronary arteries may differ in their responsiveness to 5-HT or ketanserin, these data suggest that ischemia from ergonovine-induced coronary vasospasm is not mediated by 5-HT receptors.
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PMID:Ergonovine-induced myocardial ischemia: no role for serotonergic receptors? 673 73

The induction of alkalosis has been proposed as provocative test of coronary spasm in patients affected by vasospastic angina. We submitted to the test 43 patients, affected by angina with a previous documentation of spontaneous ischemia (19 patients with ST elevation and 24 patients with ST depression at the EKG registered during pain). Twelve patients had normal coronary arteries; in 14 patients a significant stenosis of a single vessel was present; in 15 patients 2 vessels were involved and in 2 a 3-vessel disease was demonstrated. The test induced ischemia in 17 patients (39.6%). The positivity of the test was strictly dependent on the period of time elapsed between the last documented crisis of angina and the provocative test: it induced ischemia in 75% of the patients who underwent the test in the acute phase: on the other hand it was constantly negative in patients who had not complained of anginal pain for more than 6 months. In the screening of patients with chest pain at rest, the test of alkalosis does not seem, therefore, useful as a diagnostic tool.
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PMID:[The alkalinization test in the diagnosis of spontaneous angina]. 673 5

The results of coronary bypass surgery are generally not as good in Prinzmetal angina as in classical angina pectoris. The percentage of myocardial infarction, recurrent angina and death is much higher. One reason for these failures could be the persistence of coronary spasm. In order to prevent this, denervation of the pre-supra and retro aortic nerve plexuses was carried out in 56 patients (54 male, 2 female) with Prinzmetal angina and operable coronary arterial lesions. Forty patients had documented coronary spasm mainly of the left anterior descending (20 cases) or the right coronary artery (13 cases). Surgery consisted of cardiac denervation associated with direct myocardial revascularisation by implantation of I (37 cases), 2 (13 cases) or 3 (6 cases) aorto coronary bypass grafts. Two deaths were observed in the perioperative period (one low output syndrome and one severe arrhythmia) and one myocardial infarction in the postoperative period. Of the 54 survivors, 49 are asymptomatic and 2 have recurrent spontaneous angina. Exercise electrocardiography in 44 patients was negative in 40 cases. Continuous electrocardiographic recordings (Holter method) in 33 patients was negative for ischemia and of 25 bypass grafts controlled, 24 were patent. Seventy five methylergometrine provocation tests were performed: only 2 were positive, both in patients with recurrent attacks. Therefore, with respect to the total numbers of recurrent angina (2), post operative infarction (I), peri and post operative deaths (3), the percentage of poor results was only 10,7 p. 100, almost three times lower than in previously reported series. In conclusion, we can say that the association of cardiac denervation with coronary bypass surgery significantly improves the percentage of good results (89,3 p. 100 of patients presenting with Prinzmetal angina).
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PMID:[Surgical treatment of Prinzmetal's angina pectoris by plexectomy associated with aortocoronary bypass. Apropos of 56 cases]. 681 Jul 89

To examine the possible existence of collateral circulation during coronary artery spasm, we attempted to visualize the transient appearance of collateral vessels that could serve to salvage otherwise jeopardized ischemic areas. In three patients with vasospastic angina, total spastic obstruction of a major coronary artery was associated with transient collateral augmentation, which was supplied by the nonspastic artery during anginal period associated with ST-segment depression. These collateral vessels disappeared when the angina and ST changes resolved after nitroglycerin administration. These findings suggest that the collateral blood supply could transiently occur through preexisting vessels to perfuse the ischemic area during coronary artery spasm and that such collateral flow could have a role in preventing transmural myocardial ischemia, resulting in a lesser degree of ischemia associated with ST-segment depression.
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PMID:Transient collateral augmentation during coronary arterial spasm associated with ST-segment depression. 682 15

Hyperventilation Thallium-201 imaging was evaluated for the examination of the existence of ischemia in the cases of diffuse vasoconstriction under the ergonovine maleate provocative test for coronary artery. Transient myocardial perfusion defect (PD) was demonstrated in 14 patients with ergonovine induced vasospasm (group S), and 13 of these patients also demonstrated redistribution (RD) (92.4%). In 14 patients with diffuse vasoconstriction (group D), nine demonstrated PD, and all of them revealed RD. On the other hand, only one of ten (10%) patients demonstrated PD and RD in a group of patients without spasm or diffuse vasoconstriction (group N). In addition, the left ventricular myocardium was divided into nine segments on a SPECT image, and the mean minimum washout rate (WOR) of each segment was evaluated. These values were compared with the percent change of the lung/heart ratio between early and delayed images (delta L/H%). Both the mean minimum WOR mean and delta L/H% of group D were significantly smaller than that of group N (p < 0.001), and only approximated to group S. Thus, the possibility of myocardial ischemia of diffuse vasoconstrictive coronary artery is implicated and such patients are supposed to be treated medically as vasospastic angina.
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PMID:[Clinical significance of diffuse vasoconstriction of coronary arteries--a study using hyperventilation thallium-201 myocardial imaging]. 759 68

The peptide hormone endothelin was initially discovered in endothelial cells. However, it has recently been shown that endothelin is produced by cardiomyocytes too. Endothelin is the most potent of all known vasoconstrictors. The coronary circulation is highly sensitive to endothelin, and intracoronary infusion may lead to lethal coronary spasm. Patients with variant angina pectoris have a higher plasma concentration of endothelin. Moreover, exposure to cold leads to a further increase in endothelin. Therefore increased production of endothelin may be an important mediator of vasospasm. Acute myocardial infarction is followed by an increase in circulating endothelin. Remaining high endothelin levels after myocardial infarction are associated with poor prognosis. Cardiomyocytes increase their production of endothelin during ischemia, and this increase may be harmful, either through an effect on the coronary circulation or by acting directly on the cardiomyocytes. Blockade of endothelin receptors has been shown to reduce the size of an infarction. Thus, intense research is directed towards discovering therapeutical agents that either inhibit production or block the effects of endothelin. Recently, an orally active endothelin receptor antagonist was discovered, and clinically useful therapeutical agents will most probably be available in the near future.
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PMID:[Endothelin--an important factor in coronary heart disease]. 799 52


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